METEOROLOGICAL TABLES.
The tables which follow are those which are now in use by the United States Weather Bureau. They were first published in the Instructions for Voluntary Observers issued in 1892, and were reprinted in 1897. The following instructions will be found of service in the use of the tables:—
Table I.—Dew-Point.
The figures in heavy type, arranged in vertical columns at each side of the page, are the air temperatures in degrees Fahrenheit, as recorded by the dry-bulb thermometer. The figures in heavy type, running across the page, denote the differences, in degrees and tenths of degrees, between the dry-bulb and wet-bulb readings, or, technically, the depression of the wet-bulb thermometer. The figures in the vertical columns denote the dew-points. Make your observation of the wet and dry-bulb thermometers and note the difference between the two readings. Find, in the vertical columns of heavy type, the temperature corresponding to your dry-bulb reading, or the nearest temperature to that. Then look along the horizontal lines of figures in heavy type for the figure which corresponds exactly, or most nearly, with the difference between your wet and dry-bulb readings. Look down the vertical column under this latter figure until you reach the horizontal line corresponding to your dry-bulb reading. At this point the figures in the vertical column give the dew-point of the air at the time of your observation.
Example: Air Temperature (dry bulb), 47°; Wet Bulb, 44°; Difference, 3°. On page 148 will be found the table containing both 47° (dry bulb) and 3° (depression of the dew-point). In the twenty-eighth line of this table and in the seventh column will be found the dew-point, viz., 41°.
Example: Air Temperature, 61.5°; Wet Bulb, 55.5°; Difference, 6°.
In this case 61.5° is not found in the vertical columns of dry-bulb readings, but 61° and 62° are found. The dew-point, with a difference between wet and dry-bulb readings of 6°, for an air temperature of 61°, is 50°; for an air temperature of 62°, it is 52°. Evidently, then, for an air temperature of 61.5° the dew-point will be 51°, i.e., halfway between 50° and 52°. This method of determining dew-points at air temperatures or with depressions of the wet-bulb thermometer which are not given exactly in the tables, is known as interpolation.
Example: Air Temperature, 93°; Wet Bulb, 90.5°; Difference, 2.5°. Our table gives no dew-points for wet-bulb depressions of 2.5°, with air temperature 93°, but we find (on page 152) that for air temperature 93° and depression of wet bulb of 2°, the dew-point is 91°, while for a wet-bulb depression of 3°, the dew-point is 89°. By the method of interpolation we can readily determine the dew-point in the special case under consideration as 90°, i.e., halfway between 89° and 91°.
Table II.—Relative Humidity.
The general plan of this table is the same as that of Table I. The figures in the vertical columns are the relative humidities (in percentages) corresponding to the different readings of the wet and dry-bulb thermometers.
Table III.—Reduction of Barometer to 32°.
The figures in heavy type, arranged in vertical columns at the left of the page, refer to the temperature in degrees Fahrenheit, as indicated by the attached thermometer. The figures in heavy type, running across the top of the page, are the barometer readings in inches and tenths. Make a reading of the attached thermometer and of the barometer. Find in the vertical column the temperature corresponding to the reading of the attached thermometer, and in the horizontal line of heavy figures the reading corresponding to the height of the barometer. The decimal in the vertical column, under the appropriate barometer reading, and in the same horizontal line with the appropriate thermometer reading, is to be subtracted from the height of the barometer as observed, thus correcting the reading to freezing. When the attached thermometer reads below 28°, the correction is additive.
Example: Attached Thermometer, 69°; Barometer, 30.00 inches; Correction, -.110; Corrected reading, 29.890 inches.
Example: Attached Thermometer, 73°; Barometer, 29.75 inches; Correction = ?
We do not find any column corresponding to a barometer reading of 29.75 inches. We do find, however, that with a barometer reading of 29.50, and an attached thermometer reading of 73, the correction is -.118 inch, and with a barometer reading of 30.00, the correction is -.120. By interpolating, as in the case of the humidity table above, we find the correction for a barometer reading of 29.75 inches, and an attached thermometer reading of 73°. The correction is -.119, and the corrected reading is 29.75 - .119 = 29.63 inches.
Table IV.—Reduction of Barometer to Sea Level.
The figures in heavy type, in the left-hand vertical columns, are the heights, in feet, of the barometer above sea level. The figures in heavy type at the top of the columns, running across the page, are the readings of the ordinary thermometer. The numbers of inches and hundredths of inches to be subtracted from the barometer reading (corrected for temperature by Table III), for the different heights above sea level, are given in the vertical columns.
The altitude above sea level of the city or town at which the observation is made should be ascertained as accurately as possible from some recognized authority, as, e.g., from a railroad survey; from Government measurements, or from some engineer’s office. The correction to be made is determined by a simple inspection of the table or by the method of interpolation.
Example: Altitude of Barometer above sea level, 840 feet; Temperature of the air, 40°; Correction, +.931 inch.
Example: Altitude of Barometer above sea level, 205 feet; Temperature of the air, 45°; Correction = ?
Here 205 feet and 45° are neither of them found in the table. Hence a double interpolation is necessary. For 200 feet and 40° the correction is +.224 inch. For 200 feet and 50° the correction is +.220 inch. Hence for 200 feet and 45° the correction is +.222 inch. For 210 feet and 40° the correction is +.235 inch. For 210 feet and 50° the correction is +.231 inch. Hence for 210 feet and 45° the correction is +.233 inch. Now for 205 feet we should have a correction midway between +.235 inch and +.233 inch or +.234 inch.
Table I.—Temperature of the Dew-Point, in Degrees Fahrenheit.
| t | Difference between the dry and wet thermometers (t-t') | t |
| (Dry ther.) | 0°.2 | 0°.4 | 0°.6 | 0°.8 | 1°.0 | 1°.2 | 1°.4 | 1°.6 | 1°.8 | 2°.0 | 2°.2 | 2°.4 | 2°.6 | (Dry ther.) |
| -40 | -52 | | | | | | | | | | | | | -40 |
| -39 | -50 | | | | | | | | | | | | | -39 |
| -38 | -49 | | | | | | | | | | | | | -38 |
| -37 | -48 | | | | | | | | | | | | | -37 |
| -36 | -46 | | | | | | | | | | | | | -36 |
| -35 | -44 | | | | | | | | | | | | | -35 |
| -34 | -43 | -58 | | | | | | | | | | | | -34 |
| -33 | -42 | -55 | | | | | | | | | | | | -33 |
| -32 | -40 | -52 | | | | | | | | | | | | -32 |
| -31 | -38 | -49 | | | | | | | | | | | | -31 |
| -30 | -36 | -47 | | | | | | | | | | | | -30 |
| -29 | -35 | -44 | | | | | | | | | | | | -29 |
| -28 | -33 | -42 | -56 | | | | | | | | | | | -28 |
| -27 | -32 | -40 | -52 | | | | | | | | | | | -27 |
| -26 | -30 | -37 | -48 | | | | | | | | | | | -26 |
| -25 | -29 | -35 | -45 | | | | | | | | | | | -25 |
| -24 | -28 | -34 | -43 | -58 | | | | | | | | | | -24 |
| -23 | -27 | -32 | -40 | -53 | | | | | | | | | | -23 |
| -22 | -26 | -30 | -37 | -49 | | | | | | | | | | -22 |
| -21 | -25 | -29 | -35 | -45 | | | | | | | | | | -21 |
| -20 | -23 | -28 | -33 | -41 | -55 | | | | | | | | | -20 |
| -19 | -22 | -26 | -31 | -38 | -50 | | | | | | | | | -19 |
| -18 | -21 | -25 | -29 | -35 | -45 | | | | | | | | | -18 |
| -17 | -20 | -23 | -27 | -32 | -41 | -55 | | | | | | | | -17 |
| -16 | -19 | -22 | -26 | -30 | -37 | -49 | | | | | | | | -16 |
| -15 | -17 | -20 | -24 | -28 | -34 | -44 | | | | | | | | -15 |
| -14 | -16 | -19 | -22 | -26 | -31 | -39 | -52 | | | | | | | -14 |
| -13 | -15 | -18 | -21 | -25 | -29 | -35 | -46 | | | | | | | -13 |
| -12 | -14 | -17 | -20 | -23 | -27 | -32 | -41 | -55 | | | | | | -12 |
| -11 | -13 | -16 | -18 | -21 | -25 | -30 | -36 | -48 | | | | | | -11 |
| -10 | -12 | -14 | -17 | -20 | -23 | -27 | -33 | -42 | -58 | | | | | -10 |
| -9 | -11 | -13 | -15 | -18 | -21 | -25 | -30 | -37 | -48 | | | | | -9 |
| -8 | -10 | -12 | -14 | -17 | -20 | -23 | -27 | -33 | -42 | -58 | | | | -8 |
| -7 | -9 | -11 | -13 | -15 | -18 | -21 | -25 | -30 | -36 | -48 | | | | -7 |
| -6 | -8 | -10 | -12 | -14 | -16 | -19 | -23 | -27 | -32 | -41 | -56 | | | -6 |
| -5 | -7 | -8 | -10 | -12 | -15 | -17 | -21 | -24 | -29 | -35 | -47 | | | -5 |
| -4 | -6 | -7 | -9 | -11 | -13 | -16 | -19 | -22 | -26 | -31 | -39 | -54 | | -4 |
| -3 | -4 | -6 | -8 | -10 | -12 | -14 | -17 | -20 | -23 | -28 | -33 | -44 | | -3 |
| -2 | -3 | -5 | -6 | -8 | -10 | -12 | -15 | -18 | -21 | -24 | -29 | -36 | -48 | -2 |
| -1 | -2 | -4 | -5 | -7 | -9 | -11 | -13 | -16 | -18 | -22 | -26 | -31 | -39 | -1 |
| ±0 | -1 | -3 | -4 | -6 | -7 | -9 | -11 | -14 | -16 | -19 | -23 | -27 | -33 | 0 |
| +1 | -0 | -2 | -3 | -4 | -6 | -8 | -10 | -12 | -14 | -17 | -20 | -24 | -28 | +1 |
| 2 | +1 | -1 | -2 | -3 | -5 | -6 | -8 | -10 | -12 | -15 | -17 | -21 | -25 | 2 |
| 3 | 2 | +1 | -1 | -2 | -3 | -5 | -7 | -8 | -10 | -13 | -15 | -18 | -21 | 3 |
| 4 | 3 | +2 | 0 | -1 | -2 | -4 | -5 | -7 | -9 | -11 | -13 | -16 | -19 | 4 |
| 5 | 4 | 3 | +1 | 0 | -1 | -2 | -4 | -5 | -7 | -9 | -11 | -14 | -16 | 5 |
| 6 | 5 | 4 | 3 | +1 | 0 | -1 | -3 | -4 | -6 | -7 | -9 | -12 | -14 | 6 |
| 7 | 6 | 5 | 4 | 3 | +1 | 0 | -1 | -3 | -4 | -6 | -8 | -10 | -12 | 7 |
| 8 | 7 | 6 | 5 | 4 | 3 | +1 | 0 | -1 | -3 | -4 | -6 | -8 | -10 | 8 |
| 9 | 8 | 7 | 6 | 5 | 4 | 3 | +1 | 0 | -1 | -3 | -4 | -6 | -8 | 9 |
| 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | +1 | 0 | -1 | -3 | -4 | -6 | 10 |
| 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | +2 | 0 | -1 | -3 | -4 | 11 |
| 12 | 11 | 10 | 9 | 9 | 8 | 7 | 5 | 4 | 3 | +2 | 0 | -1 | -2 | 12 |
| 13 | 12 | 11 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 3 | +2 | +1 | -1 | 13 |
| 14 | 13 | 12 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 2 | +1 | 14 |
| 15 | 14 | 13 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 15 |
| 16 | 15 | 15 | 14 | 13 | 12 | 11 | 10 | 10 | 9 | 8 | 7 | 5 | 4 | 16 |
| 17 | 16 | 16 | 15 | 14 | 13 | 12 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 17 |
| 18 | 17 | 17 | 16 | 15 | 14 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 18 |
| 19 | 18 | 18 | 17 | 16 | 15 | 15 | 14 | 13 | 12 | 11 | 10 | 10 | 9 | 19 |
| 20 | 19 | 19 | 18 | 17 | 17 | 16 | 15 | 14 | 13 | 13 | 12 | 11 | 10 | 20 |
| t. | 0°.2 | 0°.4 | 0°.6 | 0°.8 | 1°.0 | 1°.2 | 1°.4 | 1°.6 | 1°.8 | 2°.0 | 2°.2 | 2°.4 | 2°.6 | t. |
Table I.—Temperature of the Dew-Point, in Degrees Fahrenheit.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 2°.6 | 2°.8 | 3°.0 | 3°.2 | 3°.4 | 3°.6 | 3°.8 | 4°.0 | 4°.2 | 4°.4 | (Dry ther.) |
| -2 | -48 | | | | | | | | | | -2 |
| -1 | -39 | -54 | | | | | | | | | -1 |
| 0 | -33 | -43 | | | | | | | | | 0 |
| +1 | -28 | -35 | -46 | | | | | | | | +1 |
| 2 | -25 | -30 | -37 | -50 | | | | | | | 2 |
| 3 | -21 | -26 | -31 | -39 | -54 | | | | | | 3 |
| 4 | -19 | -22 | -27 | -32 | -42 | -60 | | | | | 4 |
| 5 | -16 | -19 | -23 | -28 | -34 | -45 | | | | | 5 |
| 6 | -14 | -17 | -20 | -24 | -29 | -35 | -47 | | | | 6 |
| 7 | -12 | -14 | -17 | -20 | -24 | -29 | -37 | -50 | | | 7 |
| 8 | -10 | -12 | -15 | -17 | -21 | -25 | -30 | -38 | -53 | | 8 |
| 9 | -8 | -10 | -12 | -15 | -18 | -21 | -25 | -31 | -39 | -55 | 9 |
| 10 | -6 | -8 | -10 | -12 | -15 | -18 | -21 | -26 | -31 | -40 | 10 |
| 11 | -4 | -6 | -8 | -10 | -12 | -15 | -18 | -21 | -26 | -31 | 11 |
| 12 | -2 | -4 | -6 | -8 | -10 | -12 | -15 | -18 | -21 | -26 | 12 |
| 13 | -1 | -2 | -4 | -5 | -7 | -9 | -12 | -14 | -17 | -21 | 13 |
| 14 | +1 | 0 | -2 | -3 | -5 | -7 | -9 | -11 | -14 | -17 | 14 |
| 15 | 3 | +1 | 0 | -2 | -3 | -5 | -7 | -9 | -11 | -14 | 15 |
| 16 | 4 | 3 | +2 | 0 | -1 | -3 | -4 | -6 | -8 | -10 | 16 |
| 17 | 6 | 5 | 3 | +2 | +1 | -1 | -2 | -4 | -6 | -8 | 17 |
| 18 | 7 | 6 | 5 | 4 | 2 | +1 | 0 | -2 | -3 | -5 | 18 |
| 19 | 9 | 8 | 7 | 5 | 4 | 3 | +1 | 0 | -1 | -3 | 19 |
| 20 | 10 | 9 | 8 | 7 | 6 | 5 | 3 | +2 | +1 | -1 | 20 |
| t. | 2°.6 | 2°.8 | 3°.0 | 3°.2 | 3°.4 | 3°.6 | 3°.8 | 4°.0 | 4°.2 | 4°.4 | t. |
| | | | | | | | | | | |
| t. | 4°.6 | 4°.8 | 5°.0 | 5°.2 | 5°.4 | 5°.6 | 5°.8 | 6°.0 | 6°.2 | 6°.4 | t. |
| 8 | | | | | | | | | | | 8 |
| 9 | | | | | | | | | | | 9 |
| 10 | -57 | | | | | | | | | | 10 |
| 11 | -41 | -60 | | | | | | | | | 11 |
| 12 | -31 | -41 | -59 | | | | | | | | 12 |
| 13 | -25 | -31 | -40 | -58 | | | | | | | 13 |
| 14 | -20 | -25 | -30 | -39 | -56 | | | | | | 14 |
| 15 | -16 | -20 | -24 | -30 | -38 | -53 | | | | | 15 |
| 16 | -13 | -16 | -19 | -23 | -28 | -36 | -50 | | | | 16 |
| 17 | -10 | -12 | -15 | -18 | -22 | -27 | -34 | -47 | | | 17 |
| 18 | -7 | -9 | -12 | -14 | -17 | -21 | -26 | -32 | -44 | | 18 |
| 19 | -5 | -7 | -9 | -11 | -14 | -17 | -20 | -25 | -30 | -40 | 19 |
| 20 | -2 | -4 | -6 | -8 | -10 | -13 | -16 | -19 | -23 | -29 | 20 |
| t. | 4°.6 | 4°.8 | 5°.0 | 5°.2 | 5°.4 | 5°.6 | 5°.8 | 6°.0 | 6°.2 | 6°.4 | t. |
Table I.—Temperature of the Dew-Point, in Degrees Fahrenheit.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 6°.0 | 6°.5 | 7°.0 | 7°.5 | 8°.0 | 8°.5 | 9°.0 | 9°.5 | 10°.0 | 10°.5 | 11°.0 | 11°.5 | 12°.0 | (Dry ther.) |
| 19 | -25 | | | | | | | | | | | | | 19 |
| 20 | -19 | -32 | | | | | | | | | | | | 20 |
| 21 | -15 | -24 | -47 | | | | | | | | | | | 21 |
| 22 | -11 | -19 | -31 | | | | | | | | | | | 22 |
| 23 | -8 | -14 | -24 | -45 | | | | | | | | | | 23 |
| 24 | -5 | -10 | -18 | -30 | | | | | | | | | | 24 |
| 25 | -2 | -7 | -13 | -22 | -42 | | | | | | | | | 25 |
| 26 | 0 | -4 | -9 | -17 | -28 | | | | | | | | | 26 |
| 27 | +3 | -1 | -6 | -12 | -20 | -37 | | | | | | | | 27 |
| 28 | 5 | +1 | -3 | -8 | -15 | -25 | -54 | | | | | | | 28 |
| 29 | 7 | 4 | 0 | -4 | -10 | -18 | -32 | | | | | | | 29 |
| 30 | 9 | 6 | +2 | -2 | -6 | -13 | -22 | -43 | | | | | | 30 |
| 31 | 11 | 8 | 5 | +1 | -3 | -8 | -15 | -27 | | | | | | 31 |
| 32 | 13 | 10 | 7 | 4 | 0 | -4 | -10 | -18 | -33 | | | | | 32 |
| 33 | 14 | 12 | 9 | 6 | +3 | -1 | -6 | -12 | -22 | -44 | | | | 33 |
| 34 | 16 | 14 | 11 | 8 | 6 | +2 | -2 | -8 | -15 | -27 | | | | 34 |
| 35 | 18 | 15 | 13 | 10 | 8 | 5 | +1 | -4 | -9 | -18 | -32 | | | 35 |
| 36 | 19 | 17 | 15 | 12 | 10 | 8 | 4 | 0 | -5 | -12 | -20 | -42 | | 36 |
| 37 | 21 | 19 | 17 | 14 | 12 | 9 | 6 | +3 | -2 | -6 | -14 | -25 | -52 | 37 |
| 38 | 22 | 20 | 19 | 16 | 14 | 11 | 9 | 6 | +2 | -2 | -8 | -16 | -29 | 38 |
| 39 | 24 | 22 | 20 | 18 | 16 | 14 | 11 | 8 | 5 | +1 | -4 | -10 | -18 | 39 |
| 40 | 25 | 23 | 22 | 20 | 18 | 16 | 13 | 11 | 8 | 4 | 0 | -5 | -12 | 40 |
| 41 | 26 | 25 | 23 | 21 | 20 | 17 | 15 | 13 | 10 | 7 | +4 | -1 | -6 | 41 |
| 42 | 27 | 26 | 24 | 23 | 21 | 19 | 18 | 15 | 12 | 10 | 7 | +3 | -2 | 42 |
| 43 | 29 | 27 | 26 | 24 | 23 | 21 | 19 | 17 | 14 | 12 | 9 | 6 | +2 | 43 |
| 44 | 30 | 28 | 27 | 26 | 24 | 22 | 20 | 18 | 16 | 14 | 12 | 9 | 6 | 44 |
| 45 | 31 | 30 | 28 | 27 | 25 | 24 | 22 | 20 | 18 | 16 | 13 | 11 | 8 | 45 |
| 46 | 32 | 31 | 30 | 28 | 27 | 25 | 24 | 22 | 20 | 18 | 16 | 13 | 11 | 46 |
| 47 | 33 | 32 | 31 | 29 | 28 | 26 | 25 | 23 | 22 | 20 | 18 | 15 | 13 | 47 |
| 48 | 35 | 33 | 32 | 30 | 29 | 28 | 26 | 25 | 23 | 21 | 20 | 17 | 15 | 48 |
| 49 | 36 | 34 | 33 | 32 | 31 | 29 | 28 | 26 | 25 | 23 | 21 | 19 | 17 | 49 |
| 50 | 37 | 35 | 34 | 33 | 32 | 31 | 29 | 28 | 26 | 24 | 23 | 21 | 19 | 50 |
| 51 | 38 | 37 | 36 | 34 | 33 | 32 | 31 | 29 | 28 | 26 | 24 | 22 | 21 | 51 |
| 52 | 40 | 38 | 37 | 36 | 34 | 33 | 32 | 30 | 29 | 28 | 26 | 24 | 23 | 52 |
| 53 | 41 | 39 | 38 | 37 | 36 | 34 | 33 | 32 | 30 | 29 | 28 | 26 | 24 | 53 |
| 54 | 42 | 41 | 40 | 39 | 37 | 36 | 34 | 33 | 32 | 30 | 29 | 27 | 26 | 54 |
| 55 | 43 | 42 | 41 | 40 | 39 | 37 | 36 | 34 | 33 | 32 | 30 | 29 | 28 | 55 |
| 56 | 44 | 43 | 42 | 41 | 40 | 39 | 37 | 36 | 34 | 33 | 32 | 30 | 29 | 56 |
| 57 | 46 | 45 | 44 | 42 | 41 | 40 | 39 | 37 | 36 | 35 | 33 | 32 | 30 | 57 |
| 58 | 47 | 46 | 45 | 44 | 42 | 41 | 40 | 39 | 37 | 36 | 35 | 33 | 32 | 58 |
| 59 | 48 | 47 | 46 | 45 | 44 | 43 | 41 | 40 | 39 | 38 | 36 | 35 | 33 | 59 |
| 60 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 41 | 40 | 39 | 38 | 36 | 35 | 60 |
| 61 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 39 | 38 | 36 | 61 |
| 62 | 52 | 51 | 50 | 49 | 48 | 47 | 45 | 44 | 43 | 42 | 41 | 39 | 38 | 62 |
| 63 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 45 | 44 | 43 | 42 | 41 | 39 | 63 |
| 64 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 43 | 42 | 41 | 64 |
| 65 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 43 | 42 | 65 |
| 66 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 66 |
| 67 | 57 | 56 | 55 | 55 | 54 | 53 | 52 | 51 | 50 | 48 | 47 | 46 | 45 | 67 |
| 68 | 58 | 57 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 47 | 46 | 68 |
| 69 | 59 | 58 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 69 |
| 70 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 70 |
| 71 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 55 | 54 | 53 | 52 | 51 | 71 |
| 72 | 63 | 62 | 61 | 60 | 59 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 72 |
| 73 | 64 | 63 | 62 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 73 |
| 74 | 65 | 64 | 63 | 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 74 |
| 75 | 66 | 65 | 64 | 64 | 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 56 | 75 |
| 76 | 67 | 66 | 65 | 65 | 64 | 63 | 62 | 61 | 61 | 60 | 59 | 58 | 57 | 76 |
| 77 | 68 | 67 | 67 | 66 | 65 | 64 | 63 | 62 | 62 | 61 | 60 | 59 | 58 | 77 |
| 78 | 69 | 68 | 68 | 67 | 66 | 66 | 65 | 64 | 63 | 62 | 61 | 60 | 59 | 78 |
| 79 | 70 | 69 | 69 | 68 | 67 | 67 | 66 | 65 | 64 | 63 | 62 | 61 | 61 | 79 |
| 80 | 72 | 71 | 70 | 69 | 68 | 68 | 67 | 66 | 65 | 64 | 63 | 62 | 62 | 80 |
| t. | 6°.0 | 6°.5 | 7°.0 | 7°.5 | 8°.0 | 8°.5 | 9°.0 | 9°.5 | 10°.0 | 10°.5 | 11°.0 | 11°.5 | 12°.0 | t. |
Table I.—Temperature of the Dew-Point, in Degrees Fahrenheit.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | 25°.0 | 26°.0 | 27°.0 | 28°.0 | 29°.0 | 30°.0 | (Dry ther.) |
| 55 | -8 | | | | | | | | | | | | | 55 |
| 56 | -2 | -19 | | | | | | | | | | | | 56 |
| 57 | +2 | -10 | -48 | | | | | | | | | | | 57 |
| 58 | 6 | -3 | -22 | | | | | | | | | | | 58 |
| 59 | 9 | +1 | -12 | | | | | | | | | | | 59 |
| 60 | 12 | 5 | -5 | -25 | | | | | | | | | | 60 |
| 61 | 15 | 9 | 0 | -14 | | | | | | | | | | 61 |
| 62 | 18 | 12 | +5 | -6 | -28 | | | | | | | | | 62 |
| 63 | 20 | 15 | 9 | 0 | -14 | | | | | | | | | 63 |
| 64 | 22 | 18 | 12 | +4 | -6 | -32 | | | | | | | | 64 |
| 65 | 24 | 20 | 15 | 9 | 0 | -16 | | | | | | | | 65 |
| 66 | 26 | 22 | 18 | 12 | +4 | -7 | -34 | | | | | | | 66 |
| 67 | 28 | 24 | 20 | 15 | 9 | -1 | -16 | | | | | | | 67 |
| 68 | 30 | 26 | 23 | 18 | 12 | +4 | -7 | -37 | | | | | | 68 |
| 69 | 32 | 28 | 25 | 20 | 15 | 8 | 0 | -17 | | | | | | 69 |
| 70 | 33 | 30 | 27 | 23 | 19 | 12 | +5 | -7 | -39 | | | | | 70 |
| 71 | 35 | 32 | 29 | 25 | 21 | 16 | 9 | 0 | -17 | | | | | 71 |
| 72 | 37 | 33 | 31 | 27 | 23 | 18 | 13 | +5 | -6 | -39 | | | | 72 |
| 73 | 38 | 35 | 32 | 29 | 25 | 21 | 16 | 10 | 0 | -16 | | | | 73 |
| 74 | 40 | 37 | 34 | 31 | 28 | 24 | 19 | 13 | +6 | -6 | -37 | | | 74 |
| 75 | 42 | 39 | 36 | 32 | 30 | 26 | 22 | 16 | 10 | 0 | -16 | | | 75 |
| 76 | 43 | 41 | 38 | 34 | 32 | 28 | 24 | 20 | 14 | +6 | -6 | -34 | | 76 |
| 77 | 45 | 42 | 40 | 36 | 33 | 30 | 26 | 22 | 17 | 11 | +1 | -14 | | 77 |
| 78 | 47 | 44 | 41 | 38 | 35 | 32 | 28 | 24 | 20 | 14 | 7 | -4 | -30 | 78 |
| 79 | 48 | 46 | 43 | 40 | 37 | 34 | 31 | 27 | 23 | 18 | 11 | +2 | -13 | 79 |
| 80 | 50 | 47 | 45 | 42 | 39 | 36 | 32 | 29 | 25 | 21 | 15 | 8 | -3 | 80 |
| t | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | 25°.0 | 26°.0 | 27°.0 | 28°.0 | 29°.0 | 30°.0 | t |
Table I.—Temperature of the Dew-Point, in Degrees Fahrenheit.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 1°.0 | 2°.0 | 3°.0 | 4°.0 | 5°.0 | 6°.0 | 7°.0 | 8°.0 | 9°.0 | 10°.0 | 11°.0 | 12°.0 | (Dry ther.) |
| 80 | 79 | 77 | 76 | 74 | 73 | 72 | 70 | 68 | 67 | 65 | 63 | 62 | 80 |
| 81 | 80 | 78 | 77 | 75 | 74 | 73 | 71 | 70 | 68 | 66 | 65 | 63 | 81 |
| 82 | 81 | 79 | 78 | 77 | 75 | 74 | 72 | 71 | 69 | 68 | 66 | 64 | 82 |
| 83 | 82 | 80 | 79 | 78 | 76 | 75 | 73 | 72 | 70 | 69 | 67 | 65 | 83 |
| 84 | 83 | 81 | 80 | 79 | 77 | 76 | 74 | 73 | 71 | 70 | 68 | 67 | 84 |
| 85 | 84 | 82 | 81 | 80 | 78 | 77 | 75 | 74 | 72 | 71 | 69 | 68 | 85 |
| 86 | 85 | 83 | 82 | 81 | 79 | 78 | 76 | 75 | 73 | 72 | 71 | 69 | 86 |
| 87 | 86 | 84 | 83 | 82 | 80 | 79 | 78 | 76 | 74 | 73 | 72 | 70 | 87 |
| 88 | 87 | 85 | 84 | 83 | 81 | 80 | 79 | 77 | 75 | 74 | 73 | 71 | 88 |
| 89 | 88 | 86 | 85 | 84 | 82 | 81 | 80 | 78 | 76 | 76 | 74 | 72 | 89 |
| 90 | 89 | 87 | 86 | 85 | 84 | 82 | 81 | 79 | 78 | 77 | 75 | 74 | 90 |
| 91 | 90 | 88 | 87 | 86 | 85 | 83 | 82 | 80 | 79 | 78 | 76 | 75 | 91 |
| 92 | 91 | 89 | 88 | 87 | 86 | 84 | 83 | 82 | 80 | 79 | 77 | 76 | 92 |
| 93 | 92 | 91 | 89 | 88 | 87 | 85 | 84 | 83 | 81 | 80 | 78 | 77 | 93 |
| 94 | 93 | 92 | 90 | 89 | 88 | 86 | 85 | 84 | 82 | 81 | 80 | 78 | 94 |
| 95 | 94 | 93 | 91 | 90 | 89 | 87 | 86 | 85 | 83 | 82 | 81 | 79 | 95 |
| 96 | 95 | 94 | 92 | 91 | 90 | 88 | 87 | 86 | 84 | 83 | 82 | 80 | 96 |
| 97 | 96 | 95 | 93 | 92 | 91 | 90 | 88 | 87 | 86 | 84 | 83 | 81 | 97 |
| 98 | 97 | 96 | 94 | 93 | 92 | 91 | 89 | 88 | 87 | 85 | 84 | 83 | 98 |
| 99 | 98 | 97 | 95 | 94 | 93 | 92 | 90 | 89 | 88 | 86 | 85 | 84 | 99 |
| 100 | 99 | 98 | 96 | 95 | 94 | 93 | 91 | 90 | 89 | 87 | 86 | 85 | 100 |
| 101 | 100 | 99 | 97 | 96 | 95 | 94 | 92 | 91 | 90 | 88 | 87 | 86 | 101 |
| 102 | 101 | 100 | 98 | 97 | 96 | 95 | 93 | 92 | 91 | 90 | 88 | 87 | 102 |
| 103 | 102 | 101 | 99 | 98 | 97 | 96 | 94 | 93 | 92 | 91 | 89 | 88 | 103 |
| 104 | 103 | 102 | 100 | 99 | 98 | 97 | 96 | 94 | 93 | 92 | 90 | 89 | 104 |
| 105 | 104 | 103 | 101 | 100 | 99 | 98 | 97 | 95 | 94 | 93 | 91 | 90 | 105 |
| 106 | 105 | 104 | 102 | 101 | 100 | 99 | 98 | 96 | 95 | 94 | 93 | 91 | 106 |
| 107 | 106 | 105 | 103 | 102 | 101 | 100 | 99 | 97 | 96 | 95 | 94 | 92 | 107 |
| 108 | 107 | 106 | 104 | 103 | 102 | 101 | 100 | 98 | 97 | 96 | 95 | 93 | 108 |
| 109 | 108 | 107 | 105 | 104 | 103 | 102 | 101 | 99 | 98 | 97 | 96 | 94 | 109 |
| 110 | 109 | 108 | 107 | 105 | 104 | 103 | 102 | 101 | 99 | 98 | 97 | 96 | 110 |
| t. | 1°.0 | 2°.0 | 3°.0 | 4°.0 | 5°.0 | 6°.0 | 7°.0 | 8°.0 | 9°.0 | 10°.0 | 11°.0 | 12°.0 | t. |
Table I.—Temperature of the Dew-Point, in Degrees Fahrenheit.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 12°.0 | 13°.0 | 14°.0 | 15°.0 | 16°.0 | 17°.0 | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | (Dry ther.) |
| 80 | 62 | 60 | 58 | 56 | 54 | 52 | 50 | 47 | 45 | 42 | 39 | 36 | 32 | 80 |
| 81 | 63 | 61 | 59 | 57 | 55 | 53 | 51 | 49 | 47 | 44 | 41 | 38 | 35 | 81 |
| 82 | 64 | 62 | 61 | 59 | 57 | 55 | 53 | 50 | 48 | 45 | 43 | 40 | 37 | 82 |
| 83 | 65 | 64 | 62 | 60 | 58 | 56 | 54 | 52 | 50 | 47 | 44 | 42 | 39 | 83 |
| 84 | 67 | 65 | 63 | 61 | 59 | 57 | 55 | 53 | 51 | 49 | 46 | 43 | 41 | 84 |
| 85 | 68 | 66 | 64 | 62 | 61 | 59 | 57 | 55 | 53 | 50 | 48 | 45 | 42 | 85 |
| 86 | 69 | 67 | 66 | 64 | 62 | 60 | 58 | 56 | 54 | 52 | 49 | 47 | 44 | 86 |
| 87 | 70 | 68 | 67 | 65 | 63 | 61 | 59 | 57 | 55 | 53 | 51 | 48 | 46 | 87 |
| 88 | 71 | 70 | 68 | 66 | 64 | 63 | 61 | 59 | 57 | 55 | 53 | 50 | 48 | 88 |
| 89 | 72 | 71 | 69 | 67 | 66 | 64 | 62 | 60 | 58 | 56 | 54 | 52 | 49 | 89 |
| 90 | 74 | 72 | 70 | 69 | 67 | 65 | 63 | 62 | 60 | 58 | 56 | 53 | 51 | 90 |
| 91 | 75 | 73 | 72 | 70 | 68 | 67 | 65 | 63 | 61 | 59 | 57 | 55 | 53 | 91 |
| 92 | 76 | 74 | 73 | 71 | 69 | 68 | 66 | 64 | 62 | 60 | 58 | 56 | 54 | 92 |
| 93 | 77 | 75 | 74 | 72 | 71 | 69 | 67 | 66 | 64 | 62 | 60 | 58 | 56 | 93 |
| 94 | 78 | 77 | 75 | 73 | 72 | 70 | 69 | 67 | 65 | 63 | 61 | 59 | 57 | 94 |
| 95 | 79 | 78 | 76 | 75 | 73 | 71 | 70 | 68 | 66 | 64 | 63 | 61 | 59 | 95 |
| 96 | 80 | 79 | 77 | 76 | 74 | 73 | 71 | 69 | 68 | 66 | 64 | 62 | 60 | 96 |
| 97 | 81 | 80 | 78 | 77 | 75 | 74 | 72 | 71 | 69 | 67 | 65 | 63 | 61 | 97 |
| 98 | 83 | 81 | 80 | 78 | 77 | 75 | 73 | 72 | 70 | 68 | 67 | 65 | 63 | 98 |
| 99 | 84 | 82 | 81 | 79 | 78 | 76 | 75 | 73 | 71 | 70 | 68 | 66 | 64 | 99 |
| 100 | 85 | 83 | 82 | 80 | 79 | 77 | 76 | 74 | 73 | 71 | 69 | 67 | 66 | 100 |
| 101 | 86 | 84 | 83 | 82 | 80 | 79 | 77 | 75 | 74 | 72 | 71 | 69 | 67 | 101 |
| 102 | 87 | 85 | 84 | 83 | 81 | 80 | 78 | 77 | 75 | 73 | 72 | 70 | 68 | 102 |
| 103 | 88 | 87 | 85 | 84 | 82 | 81 | 79 | 78 | 76 | 75 | 73 | 71 | 70 | 103 |
| 104 | 89 | 88 | 86 | 85 | 83 | 82 | 81 | 79 | 78 | 76 | 74 | 73 | 71 | 104 |
| 105 | 90 | 89 | 87 | 86 | 85 | 83 | 82 | 80 | 79 | 77 | 76 | 74 | 72 | 105 |
| 106 | 91 | 90 | 89 | 87 | 86 | 84 | 83 | 81 | 80 | 78 | 77 | 75 | 74 | 106 |
| 107 | 92 | 91 | 90 | 88 | 87 | 85 | 84 | 83 | 81 | 80 | 78 | 76 | 75 | 107 |
| 108 | 93 | 92 | 91 | 89 | 88 | 87 | 85 | 84 | 82 | 81 | 79 | 78 | 76 | 108 |
| 109 | 94 | 93 | 92 | 90 | 89 | 88 | 86 | 85 | 83 | 82 | 80 | 79 | 77 | 109 |
| 110 | 96 | 94 | 93 | 92 | 90 | 89 | 87 | 86 | 85 | 83 | 82 | 80 | 79 | 110 |
| t. | 12°.0 | 13°.0 | 14°.0 | 15°.0 | 16°.0 | 17°.0 | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | t. |
Table I.—Temperature of the Dew-Point, in Degrees Fahrenheit.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 36°.0 | 37°.0 | 38°.0 | 39°.0 | 40°.0 | 41°.0 | 42°.0 | 43°.0 | 44°.0 | 45°.0 | 46°.0 | 47°.0 | 48°.0 | (Dry ther.) |
| 89 | -28 | | | | | | | | | | | | | 89 |
| 90 | -10 | | | | | | | | | | | | | 90 |
| 91 | 0 | -22 | | | | | | | | | | | | 91 |
| 92 | +7 | -7 | -16 | | | | | | | | | | | 92 |
| 93 | 12 | +2 | -4 | | | | | | | | | | | 93 |
| 94 | 16 | 8 | +4 | -37 | | | | | | | | | | 94 |
| 95 | 20 | 13 | 10 | -12 | | | | | | | | | | 95 |
| 96 | 24 | 15 | 15 | -1 | -25 | | | | | | | | | 96 |
| 97 | 26 | 21 | 19 | +7 | -8 | | | | | | | | | 97 |
| 98 | 29 | 25 | 23 | 12 | +2 | -18 | | | | | | | | 98 |
| 99 | 32 | 28 | 26 | 17 | 9 | -4 | -42 | | | | | | | 99 |
| 100 | 34 | 30 | 29 | 21 | 14 | +5 | -12 | | | | | | | 100 |
| 101 | 37 | 32 | 32 | 24 | 18 | 11 | 0 | -25 | | | | | | 101 |
| 102 | 39 | 35 | 34 | 27 | 22 | 16 | +7 | -7 | | | | | | 102 |
| 103 | 41 | 38 | 34 | 30 | 26 | 20 | 13 | +3 | -16 | | | | | 103 |
| 104 | 44 | 40 | 37 | 32 | 29 | 24 | 18 | 10 | -2 | -38 | | | | 104 |
| 105 | 46 | 43 | 39 | 35 | 31 | 27 | 22 | 15 | +6 | -10 | | | | 105 |
| 106 | 48 | 45 | 42 | 38 | 34 | 30 | 25 | 20 | 12 | +1 | -22 | | | 106 |
| 107 | 50 | 47 | 44 | 40 | 37 | 32 | 28 | 24 | 17 | 9 | -5 | | | 107 |
| 108 | 52 | 49 | 46 | 43 | 39 | 35 | 31 | 27 | 21 | 14 | +5 | -13 | | 108 |
| 109 | 54 | 51 | 48 | 45 | 42 | 38 | 34 | 30 | 25 | 19 | 12 | 0 | -28 | 109 |
| 110 | 55 | 53 | 50 | 47 | 44 | 41 | 37 | 33 | 28 | 23 | 17 | +8 | -7 | 110 |
| t. | 36°.0 | 37°.0 | 38°.0 | 39°.0 | 40°.0 | 41°.0 | 42°.0 | 43°.0 | 44°.0 | 45°.0 | 46°.0 | 47°.0 | 48°.0 | t. |
Table II.—Relative Humidity, per cent.
| t | Difference between the dry and wet thermometers (t—t'). | t |
| (Dry ther.) | 0°.2 | 0°.4 | 0°.6 | 0°.8 | 1°.0 | 1°.2 | 1°.4 | 1°.6 | 1°.8 | 2°.0 | 2°.2 | 2°.4 | 2°.6 | (Dry ther.) |
| -40 | 46 | | | | | | | | | | | | | -40 |
| -39 | 49 | | | | | | | | | | | | | -39 |
| -38 | 51 | | | | | | | | | | | | | -38 |
| -37 | 54 | | | | | | | | | | | | | -37 |
| -36 | 56 | | | | | | | | | | | | | -36 |
| -35 | 59 | | | | | | | | | | | | | -35 |
| -34 | 61 | 22 | | | | | | | | | | | | -34 |
| -33 | 63 | 25 | | | | | | | | | | | | -33 |
| -32 | 65 | 30 | | | | | | | | | | | | -32 |
| -31 | 67 | 34 | | | | | | | | | | | | -31 |
| -30 | 69 | 38 | | | | | | | | | | | | -30 |
| -29 | 71 | 42 | | | | | | | | | | | | -29 |
| -28 | 72 | 45 | 17 | | | | | | | | | | | -28 |
| -27 | 74 | 48 | 22 | | | | | | | | | | | -27 |
| -26 | 76 | 51 | 26 | | | | | | | | | | | -26 |
| -25 | 77 | 53 | 31 | | | | | | | | | | | -25 |
| -24 | 78 | 56 | 34 | 12 | | | | | | | | | | -24 |
| -23 | 79 | 58 | 37 | 16 | | | | | | | | | | -23 |
| -22 | 80 | 60 | 40 | 20 | | | | | | | | | | -22 |
| -21 | 81 | 62 | 44 | 25 | | | | | | | | | | -21 |
| -20 | 82 | 64 | 47 | 29 | 11 | | | | | | | | | -20 |
| -19 | 83 | 66 | 49 | 33 | 16 | | | | | | | | | -19 |
| -18 | 84 | 68 | 52 | 36 | 20 | | | | | | | | | -18 |
| -17 | 85 | 70 | 54 | 39 | 24 | 9 | | | | | | | | -17 |
| -16 | 86 | 71 | 57 | 43 | 28 | 14 | | | | | | | | -16 |
| -15 | 86 | 73 | 59 | 46 | 32 | 19 | | | | | | | | -15 |
| -14 | 87 | 74 | 61 | 48 | 36 | 23 | 10 | | | | | | | -14 |
| -13 | 88 | 76 | 63 | 51 | 39 | 27 | 15 | | | | | | | -13 |
| -12 | 88 | 77 | 65 | 53 | 42 | 30 | 19 | 7 | | | | | | -12 |
| -11 | 89 | 78 | 67 | 56 | 45 | 34 | 23 | 12 | | | | | | -11 |
| -10 | 90 | 79 | 68 | 58 | 48 | 37 | 26 | 16 | 5 | | | | | -10 |
| -9 | 90 | 80 | 70 | 60 | 50 | 40 | 30 | 20 | 10 | | | | | -9 |
| -8 | 90 | 81 | 71 | 62 | 52 | 43 | 33 | 24 | 14 | 5 | | | | -8 |
| -7 | 91 | 82 | 73 | 63 | 54 | 45 | 36 | 27 | 18 | 9 | | | | -7 |
| -6 | 91 | 83 | 74 | 65 | 56 | 48 | 39 | 31 | 22 | 13 | 5 | | | -6 |
| -5 | 92 | 83 | 75 | 67 | 58 | 50 | 42 | 34 | 25 | 17 | 9 | | | -5 |
| -4 | 92 | 84 | 76 | 68 | 60 | 52 | 45 | 37 | 29 | 21 | 13 | 5 | | -4 |
| -3 | 92 | 85 | 77 | 70 | 62 | 55 | 47 | 40 | 32 | 25 | 17 | 10 | | -3 |
| -2 | 93 | 86 | 78 | 71 | 64 | 57 | 50 | 42 | 35 | 28 | 21 | 14 | 7 | -2 |
| -1 | 93 | 86 | 79 | 72 | 66 | 59 | 52 | 45 | 38 | 31 | 25 | 18 | 11 | -1 |
| 0 | 93 | 87 | 80 | 74 | 67 | 61 | 54 | 48 | 41 | 35 | 28 | 22 | 15 | 0 |
| +1 | 94 | 87 | 81 | 75 | 69 | 63 | 56 | 50 | 44 | 38 | 32 | 25 | 19 | +1 |
| 2 | 94 | 88 | 82 | 76 | 70 | 64 | 58 | 52 | 46 | 40 | 35 | 29 | 23 | 2 |
| 3 | 94 | 88 | 83 | 77 | 71 | 66 | 60 | 54 | 49 | 43 | 37 | 32 | 26 | 3 |
| 4 | 94 | 89 | 83 | 78 | 73 | 67 | 62 | 56 | 51 | 45 | 40 | 34 | 29 | 4 |
| 5 | 95 | 89 | 84 | 79 | 74 | 68 | 63 | 58 | 53 | 48 | 42 | 37 | 32 | 5 |
| 6 | 95 | 90 | 85 | 80 | 75 | 70 | 65 | 60 | 54 | 50 | 44 | 39 | 34 | 6 |
| 7 | 95 | 90 | 85 | 80 | 76 | 71 | 66 | 61 | 56 | 51 | 47 | 42 | 37 | 7 |
| 8 | 95 | 91 | 86 | 81 | 76 | 72 | 67 | 62 | 58 | 53 | 49 | 44 | 39 | 8 |
| 9 | 96 | 91 | 86 | 82 | 77 | 73 | 68 | 64 | 59 | 55 | 51 | 46 | 42 | 9 |
| 10 | 96 | 91 | 87 | 83 | 78 | 74 | 69 | 65 | 61 | 57 | 52 | 48 | 44 | 10 |
| 11 | 96 | 92 | 87 | 83 | 79 | 75 | 71 | 66 | 62 | 58 | 54 | 50 | 46 | 11 |
| 12 | 96 | 92 | 88 | 84 | 80 | 76 | 72 | 68 | 64 | 60 | 56 | 52 | 48 | 12 |
| 13 | 96 | 92 | 88 | 84 | 81 | 77 | 73 | 69 | 65 | 61 | 58 | 54 | 50 | 13 |
| 14 | 96 | 93 | 89 | 85 | 81 | 78 | 74 | 70 | 67 | 63 | 59 | 56 | 52 | 14 |
| 15 | 96 | 93 | 89 | 86 | 82 | 79 | 75 | 71 | 68 | 64 | 61 | 57 | 54 | 15 |
| 16 | 97 | 93 | 90 | 86 | 83 | 79 | 76 | 73 | 69 | 66 | 62 | 59 | 56 | 16 |
| 17 | 97 | 93 | 90 | 87 | 83 | 80 | 77 | 74 | 70 | 67 | 64 | 60 | 57 | 17 |
| 18 | 97 | 94 | 90 | 87 | 84 | 81 | 78 | 74 | 71 | 68 | 65 | 62 | 59 | 18 |
| 19 | 97 | 94 | 91 | 88 | 84 | 81 | 78 | 75 | 72 | 69 | 66 | 63 | 60 | 19 |
| 20 | 97 | 94 | 91 | 88 | 85 | 82 | 79 | 76 | 73 | 70 | 67 | 64 | 61 | 20 |
| t. | 0°.2 | 0°.4 | 0°.6 | 0°.8 | 1°.0 | 1°.2 | 1°.4 | 1°.6 | 1°.8 | 2°.0 | 2°.2 | 2°.4 | 2°.6 | t. |
Table II.—Relative Humidity, Per cent.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 0°.5 | 1°.0 | 1°.5 | 2°.0 | 2°.5 | 3°.0 | 3°.5 | 4°.0 | 4°.5 | 5°.0 | 5°.5 | 6°.0 | (Dry ther.) |
| 20 | 92 | 85 | 77 | 70 | 63 | 56 | 48 | 41 | 34 | 27 | 20 | 13 | 20 |
| 21 | 93 | 85 | 78 | 71 | 64 | 57 | 50 | 43 | 36 | 29 | 23 | 16 | 21 |
| 22 | 93 | 86 | 79 | 72 | 65 | 58 | 51 | 45 | 38 | 32 | 25 | 19 | 22 |
| 23 | 93 | 86 | 80 | 73 | 66 | 60 | 53 | 46 | 40 | 34 | 27 | 21 | 23 |
| 24 | 93 | 87 | 80 | 74 | 67 | 61 | 54 | 48 | 42 | 36 | 30 | 24 | 24 |
| 25 | 94 | 87 | 81 | 74 | 68 | 62 | 56 | 50 | 44 | 38 | 32 | 26 | 25 |
| 26 | 94 | 88 | 81 | 75 | 69 | 63 | 57 | 51 | 45 | 40 | 34 | 28 | 26 |
| 27 | 94 | 88 | 82 | 76 | 70 | 64 | 59 | 53 | 47 | 42 | 36 | 30 | 27 |
| 28 | 94 | 88 | 82 | 77 | 71 | 65 | 60 | 54 | 49 | 43 | 38 | 33 | 28 |
| 29 | 94 | 89 | 83 | 77 | 72 | 66 | 61 | 56 | 50 | 45 | 40 | 35 | 29 |
| 30 | 94 | 89 | 84 | 78 | 73 | 67 | 62 | 57 | 52 | 47 | 41 | 36 | 30 |
| 31 | 95 | 89 | 84 | 79 | 74 | 68 | 63 | 58 | 53 | 48 | 43 | 38 | 31 |
| 32 | 95 | 90 | 84 | 79 | 74 | 69 | 64 | 59 | 54 | 50 | 45 | 40 | 32 |
| 33 | 95 | 90 | 85 | 80 | 75 | 70 | 65 | 60 | 56 | 51 | 47 | 42 | 33 |
| 34 | 95 | 91 | 86 | 81 | 75 | 72 | 67 | 62 | 57 | 53 | 48 | 44 | 34 |
| 35 | 95 | 91 | 86 | 82 | 76 | 73 | 69 | 65 | 59 | 54 | 50 | 45 | 35 |
| 36 | 96 | 91 | 86 | 82 | 77 | 73 | 70 | 66 | 61 | 56 | 51 | 47 | 36 |
| 37 | 96 | 91 | 87 | 82 | 78 | 74 | 70 | 66 | 62 | 57 | 52 | 48 | 37 |
| 38 | 96 | 92 | 87 | 83 | 79 | 75 | 71 | 67 | 63 | 58 | 54 | 50 | 38 |
| 39 | 96 | 92 | 88 | 83 | 79 | 75 | 72 | 68 | 63 | 59 | 55 | 52 | 39 |
| 40 | 96 | 92 | 88 | 84 | 80 | 76 | 72 | 68 | 64 | 60 | 56 | 53 | 40 |
| 41 | 96 | 92 | 88 | 84 | 80 | 76 | 72 | 69 | 65 | 61 | 57 | 54 | 41 |
| 42 | 96 | 92 | 88 | 84 | 81 | 77 | 73 | 69 | 65 | 62 | 58 | 55 | 42 |
| 43 | 96 | 92 | 88 | 85 | 81 | 77 | 74 | 70 | 66 | 63 | 59 | 56 | 43 |
| 44 | 96 | 92 | 88 | 85 | 81 | 78 | 74 | 70 | 67 | 63 | 60 | 57 | 44 |
| 45 | 96 | 92 | 89 | 85 | 82 | 78 | 75 | 71 | 67 | 64 | 61 | 58 | 45 |
| 46 | 96 | 93 | 89 | 85 | 82 | 79 | 75 | 72 | 68 | 65 | 61 | 58 | 46 |
| 47 | 96 | 93 | 89 | 86 | 83 | 79 | 76 | 72 | 69 | 66 | 62 | 59 | 47 |
| 48 | 96 | 93 | 89 | 86 | 83 | 79 | 76 | 73 | 69 | 66 | 63 | 60 | 48 |
| 49 | 97 | 93 | 90 | 86 | 83 | 80 | 76 | 73 | 70 | 67 | 63 | 60 | 49 |
| 50 | 97 | 93 | 90 | 87 | 83 | 80 | 77 | 74 | 70 | 67 | 64 | 61 | 50 |
| 51 | 97 | 93 | 90 | 87 | 84 | 81 | 77 | 74 | 71 | 68 | 65 | 62 | 51 |
| 52 | 97 | 94 | 90 | 87 | 84 | 81 | 78 | 75 | 72 | 69 | 66 | 63 | 52 |
| 53 | 97 | 94 | 91 | 87 | 84 | 81 | 78 | 75 | 72 | 69 | 66 | 63 | 53 |
| 54 | 97 | 94 | 91 | 88 | 85 | 82 | 79 | 76 | 73 | 70 | 67 | 64 | 54 |
| 55 | 97 | 94 | 91 | 88 | 85 | 82 | 79 | 76 | 73 | 70 | 68 | 65 | 55 |
| 56 | 97 | 94 | 91 | 88 | 85 | 82 | 80 | 77 | 74 | 71 | 68 | 65 | 56 |
| 57 | 97 | 94 | 91 | 88 | 86 | 83 | 80 | 77 | 74 | 71 | 69 | 66 | 57 |
| 58 | 97 | 94 | 91 | 89 | 86 | 83 | 80 | 78 | 75 | 72 | 69 | 67 | 58 |
| 59 | 97 | 94 | 92 | 89 | 86 | 83 | 81 | 78 | 75 | 72 | 70 | 67 | 59 |
| 60 | 97 | 94 | 92 | 89 | 86 | 84 | 81 | 78 | 75 | 73 | 70 | 68 | 60 |
| 61 | 97 | 94 | 92 | 89 | 87 | 84 | 81 | 78 | 76 | 73 | 71 | 68 | 61 |
| 62 | 97 | 95 | 92 | 89 | 87 | 84 | 81 | 79 | 76 | 74 | 71 | 69 | 62 |
| 63 | 97 | 95 | 92 | 89 | 87 | 84 | 82 | 79 | 77 | 74 | 72 | 69 | 63 |
| 64 | 97 | 95 | 92 | 90 | 87 | 85 | 82 | 79 | 77 | 74 | 72 | 70 | 64 |
| 65 | 97 | 95 | 92 | 90 | 87 | 85 | 82 | 80 | 77 | 75 | 72 | 70 | 65 |
| 66 | 97 | 95 | 92 | 90 | 87 | 85 | 82 | 80 | 78 | 75 | 73 | 71 | 66 |
| 67 | 98 | 95 | 93 | 90 | 88 | 85 | 83 | 80 | 78 | 76 | 73 | 71 | 67 |
| 68 | 98 | 95 | 93 | 90 | 88 | 85 | 83 | 81 | 78 | 76 | 74 | 71 | 68 |
| 69 | 98 | 95 | 93 | 90 | 88 | 86 | 83 | 81 | 78 | 76 | 74 | 72 | 69 |
| 70 | 98 | 95 | 93 | 90 | 88 | 86 | 83 | 81 | 79 | 77 | 74 | 72 | 70 |
| 71 | 98 | 95 | 93 | 91 | 88 | 86 | 84 | 81 | 79 | 77 | 75 | 72 | 71 |
| 72 | 98 | 95 | 93 | 91 | 88 | 86 | 84 | 82 | 79 | 77 | 75 | 73 | 72 |
| 73 | 98 | 95 | 93 | 91 | 88 | 86 | 84 | 82 | 80 | 78 | 75 | 73 | 73 |
| 74 | 98 | 95 | 93 | 91 | 88 | 86 | 84 | 82 | 80 | 78 | 76 | 74 | 74 |
| 75 | 98 | 95 | 93 | 91 | 89 | 87 | 84 | 82 | 80 | 78 | 76 | 74 | 75 |
| 76 | 98 | 95 | 93 | 91 | 89 | 87 | 85 | 82 | 80 | 78 | 76 | 74 | 76 |
| 77 | 98 | 95 | 93 | 91 | 89 | 87 | 85 | 83 | 80 | 78 | 76 | 74 | 77 |
| 78 | 98 | 96 | 93 | 91 | 89 | 87 | 85 | 83 | 81 | 79 | 77 | 75 | 78 |
| 79 | 98 | 96 | 94 | 91 | 89 | 87 | 85 | 83 | 81 | 79 | 77 | 75 | 79 |
| 80 | 98 | 96 | 94 | 92 | 89 | 87 | 85 | 83 | 81 | 79 | 77 | 75 | 80 |
| t. | 0°.5 | 1°.0 | 1°.5 | 2°.0 | 2°.5 | 3°.0 | 3°.5 | 4°.0 | 4°.5 | 5°.0 | 5°.5 | 6°.0 | t. |
Table II.—Relative Humidity, per cent.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 6°.0 | 6°.5 | 7°.0 | 7°.5 | 8°.0 | 8°.5 | 9°.0 | 9°.5 | 10°.0 | 10°.5 | 11°.0 | 11°.5 | 12°.0 | (Dry ther.) |
| 19 | 10 | | | | | | | | | | | | | 19 |
| 20 | 13 | 6 | | | | | | | | | | | | 20 |
| 21 | 16 | 9 | 2 | | | | | | | | | | | 21 |
| 22 | 19 | 12 | 6 | | | | | | | | | | | 22 |
| 23 | 21 | 15 | 9 | 2 | | | | | | | | | | 23 |
| 24 | 24 | 17 | 11 | 6 | | | | | | | | | | 24 |
| 25 | 26 | 20 | 14 | 8 | 3 | | | | | | | | | 25 |
| 26 | 28 | 23 | 17 | 11 | 6 | | | | | | | | | 26 |
| 27 | 30 | 25 | 19 | 14 | 9 | 3 | | | | | | | | 27 |
| 28 | 33 | 27 | 22 | 17 | 11 | 6 | 1 | | | | | | | 28 |
| 29 | 35 | 29 | 24 | 19 | 14 | 9 | 4 | | | | | | | 29 |
| 30 | 36 | 31 | 26 | 22 | 17 | 12 | 7 | 2 | | | | | | 30 |
| 31 | 38 | 33 | 29 | 24 | 19 | 14 | 10 | 5 | | | | | | 31 |
| 32 | 40 | 35 | 31 | 26 | 21 | 17 | 12 | 8 | 3 | | | | | 32 |
| 33 | 42 | 37 | 33 | 28 | 24 | 19 | 15 | 10 | 6 | 2 | | | | 33 |
| 34 | 44 | 39 | 35 | 30 | 26 | 21 | 17 | 13 | 9 | 4 | | | | 34 |
| 35 | 45 | 41 | 37 | 32 | 28 | 24 | 19 | 15 | 12 | 7 | 3 | | | 35 |
| 36 | 47 | 43 | 38 | 34 | 30 | 26 | 22 | 18 | 14 | 10 | 6 | 2 | | 36 |
| 37 | 48 | 44 | 40 | 36 | 32 | 28 | 24 | 20 | 16 | 12 | 8 | 5 | 1 | 37 |
| 38 | 50 | 46 | 42 | 38 | 34 | 30 | 26 | 22 | 18 | 15 | 11 | 7 | 3 | 38 |
| 39 | 52 | 48 | 44 | 40 | 36 | 32 | 28 | 24 | 20 | 17 | 13 | 9 | 6 | 39 |
| 40 | 53 | 49 | 45 | 41 | 38 | 34 | 30 | 26 | 22 | 19 | 16 | 12 | 8 | 40 |
| 41 | 54 | 50 | 46 | 43 | 39 | 36 | 32 | 29 | 24 | 21 | 18 | 14 | 10 | 41 |
| 42 | 55 | 51 | 48 | 44 | 40 | 37 | 34 | 30 | 27 | 23 | 20 | 16 | 13 | 42 |
| 43 | 56 | 52 | 49 | 46 | 42 | 38 | 35 | 32 | 29 | 25 | 22 | 19 | 15 | 43 |
| 44 | 57 | 53 | 50 | 47 | 43 | 40 | 37 | 33 | 30 | 27 | 24 | 21 | 17 | 44 |
| 45 | 58 | 54 | 51 | 48 | 44 | 41 | 38 | 35 | 32 | 29 | 25 | 22 | 19 | 45 |
| 46 | 58 | 55 | 52 | 49 | 46 | 42 | 39 | 36 | 33 | 30 | 27 | 23 | 21 | 46 |
| 47 | 59 | 56 | 53 | 50 | 47 | 44 | 40 | 38 | 34 | 31 | 28 | 25 | 22 | 47 |
| 48 | 60 | 56 | 53 | 51 | 48 | 45 | 42 | 39 | 36 | 33 | 30 | 27 | 24 | 48 |
| 49 | 60 | 57 | 54 | 52 | 49 | 46 | 43 | 40 | 37 | 34 | 31 | 29 | 26 | 49 |
| 50 | 61 | 58 | 55 | 52 | 50 | 47 | 44 | 41 | 38 | 36 | 33 | 30 | 27 | 50 |
| 51 | 62 | 59 | 56 | 53 | 50 | 48 | 45 | 42 | 39 | 37 | 34 | 31 | 28 | 51 |
| 52 | 63 | 60 | 57 | 54 | 51 | 48 | 46 | 43 | 40 | 38 | 35 | 33 | 30 | 52 |
| 53 | 63 | 61 | 58 | 55 | 52 | 49 | 47 | 44 | 42 | 39 | 36 | 34 | 31 | 53 |
| 54 | 64 | 61 | 59 | 56 | 53 | 50 | 48 | 45 | 43 | 40 | 38 | 35 | 32 | 54 |
| 55 | 65 | 62 | 59 | 57 | 54 | 51 | 49 | 46 | 43 | 41 | 39 | 36 | 34 | 55 |
| 56 | 65 | 63 | 60 | 57 | 55 | 52 | 50 | 47 | 44 | 42 | 40 | 37 | 35 | 56 |
| 57 | 66 | 64 | 61 | 58 | 55 | 53 | 50 | 48 | 45 | 43 | 40 | 38 | 36 | 57 |
| 58 | 67 | 64 | 61 | 59 | 56 | 53 | 51 | 49 | 46 | 44 | 42 | 39 | 37 | 58 |
| 59 | 67 | 65 | 62 | 60 | 57 | 54 | 52 | 49 | 47 | 45 | 43 | 40 | 38 | 59 |
| 60 | 68 | 65 | 63 | 60 | 58 | 55 | 53 | 50 | 48 | 46 | 44 | 41 | 39 | 60 |
| 61 | 68 | 66 | 63 | 61 | 58 | 56 | 54 | 51 | 49 | 47 | 44 | 42 | 40 | 61 |
| 62 | 69 | 66 | 64 | 61 | 59 | 57 | 54 | 52 | 50 | 47 | 45 | 43 | 41 | 62 |
| 63 | 69 | 67 | 64 | 62 | 60 | 57 | 55 | 53 | 51 | 48 | 46 | 44 | 42 | 63 |
| 64 | 70 | 67 | 65 | 62 | 60 | 58 | 56 | 53 | 51 | 49 | 47 | 45 | 43 | 64 |
| 65 | 70 | 68 | 65 | 63 | 61 | 59 | 56 | 54 | 52 | 50 | 48 | 46 | 44 | 65 |
| 66 | 71 | 68 | 66 | 63 | 61 | 59 | 57 | 55 | 53 | 51 | 49 | 47 | 45 | 66 |
| 67 | 71 | 69 | 66 | 64 | 62 | 60 | 58 | 55 | 53 | 51 | 49 | 47 | 45 | 67 |
| 68 | 71 | 69 | 67 | 65 | 63 | 60 | 58 | 56 | 54 | 52 | 50 | 48 | 46 | 68 |
| 69 | 72 | 70 | 67 | 65 | 63 | 61 | 59 | 57 | 55 | 53 | 51 | 49 | 47 | 69 |
| 70 | 72 | 70 | 68 | 66 | 64 | 62 | 60 | 57 | 55 | 53 | 52 | 50 | 48 | 70 |
| 71 | 72 | 70 | 68 | 66 | 64 | 62 | 60 | 58 | 56 | 54 | 52 | 50 | 48 | 71 |
| 72 | 73 | 71 | 69 | 67 | 65 | 63 | 61 | 59 | 57 | 55 | 53 | 51 | 49 | 72 |
| 73 | 73 | 71 | 69 | 67 | 65 | 63 | 61 | 59 | 57 | 55 | 53 | 52 | 50 | 73 |
| 74 | 74 | 72 | 70 | 68 | 66 | 64 | 62 | 60 | 58 | 56 | 54 | 52 | 50 | 74 |
| 75 | 74 | 72 | 70 | 68 | 66 | 64 | 62 | 60 | 58 | 56 | 55 | 53 | 51 | 75 |
| 76 | 74 | 72 | 70 | 68 | 66 | 64 | 63 | 61 | 59 | 57 | 55 | 53 | 52 | 76 |
| 77 | 74 | 73 | 71 | 69 | 67 | 65 | 63 | 61 | 59 | 57 | 56 | 54 | 52 | 77 |
| 78 | 75 | 73 | 71 | 69 | 67 | 65 | 63 | 62 | 60 | 58 | 56 | 54 | 53 | 78 |
| 79 | 75 | 73 | 71 | 70 | 68 | 66 | 64 | 62 | 60 | 58 | 57 | 55 | 53 | 79 |
| 80 | 75 | 73 | 72 | 70 | 68 | 66 | 64 | 63 | 61 | 59 | 57 | 55 | 54 | 80 |
| t. | 6°.0 | 6°.5 | 7°.0 | 7°.5 | 8°.0 | 8°.5 | 9°.0 | 9°.5 | 10°.0 | 10°.5 | 11°.0 | 11°.5 | 12°0 | t. |
Table II.—Relative Humidity, per cent.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | 25°.0 | 26°.0 | 27°.0 | 28°.0 | 29°.0 | 30°.0 | (Dry ther.) |
| 55 | 6 | 1 | | | | | | | | | | | | 55 |
| 56 | 8 | 3 | | | | | | | | | | | | 56 |
| 57 | 9 | 5 | | | | | | | | | | | | 57 |
| 58 | 11 | 7 | 2 | | | | | | | | | | | 58 |
| 59 | 12 | 8 | 4 | | | | | | | | | | | 59 |
| 60 | 14 | 10 | 6 | 2 | | | | | | | | | | 60 |
| 61 | 15 | 11 | 7 | 3 | | | | | | | | | | 61 |
| 62 | 16 | 13 | 9 | 5 | 1 | | | | | | | | | 62 |
| 63 | 18 | 14 | 10 | 7 | 3 | | | | | | | | | 63 |
| 64 | 19 | 15 | 12 | 8 | 5 | 1 | | | | | | | | 64 |
| 65 | 20 | 17 | 13 | 10 | 6 | 3 | | | | | | | | 65 |
| 66 | 22 | 18 | 14 | 11 | 8 | 4 | 1 | | | | | | | 66 |
| 67 | 23 | 19 | 16 | 12 | 9 | 6 | 2 | | | | | | | 67 |
| 68 | 24 | 20 | 17 | 14 | 10 | 7 | 4 | 1 | | | | | | 68 |
| 69 | 25 | 22 | 18 | 15 | 12 | 8 | 5 | 2 | | | | | | 69 |
| 70 | 26 | 23 | 19 | 16 | 13 | 10 | 7 | 4 | 1 | | | | | 70 |
| 71 | 27 | 24 | 20 | 17 | 14 | 11 | 8 | 5 | 2 | | | | | 71 |
| 72 | 28 | 24 | 22 | 18 | 15 | 12 | 9 | 6 | 3 | 1 | | | | 72 |
| 73 | 29 | 25 | 22 | 19 | 16 | 13 | 10 | 8 | 5 | 2 | | | | 73 |
| 74 | 30 | 26 | 23 | 20 | 18 | 15 | 12 | 9 | 6 | 3 | 1 | | | 74 |
| 75 | 31 | 27 | 24 | 21 | 19 | 16 | 13 | 10 | 7 | 5 | 2 | | | 75 |
| 76 | 31 | 28 | 25 | 22 | 20 | 17 | 14 | 11 | 8 | 6 | 3 | 1 | | 76 |
| 77 | 32 | 29 | 26 | 23 | 20 | 18 | 15 | 12 | 10 | 7 | 4 | 2 | | 77 |
| 78 | 33 | 30 | 27 | 24 | 21 | 19 | 16 | 13 | 11 | 8 | 6 | 3 | 1 | 78 |
| 79 | 34 | 31 | 28 | 25 | 22 | 19 | 17 | 14 | 12 | 9 | 7 | 4 | 2 | 79 |
| 80 | 35 | 32 | 29 | 26 | 23 | 20 | 18 | 15 | 13 | 10 | 8 | 6 | 3 | 80 |
| t. | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | 25°.0 | 26°.0 | 27°.0 | 28°.0 | 29°.0 | 30°.0 | t. |
Table II.—Relative Humidity, per cent.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 1°.0 | 2°.0 | 3°.0 | 4°.0 | 5°.0 | 6°.0 | 7°.0 | 8°.0 | 9°.0 | 10°.0 | 11°.0 | 12°.0 | (Dry ther.) |
| 80 | 96 | 92 | 87 | 83 | 79 | 75 | 72 | 68 | 64 | 61 | 57 | 54 | 80 |
| 81 | 96 | 92 | 88 | 84 | 80 | 76 | 72 | 68 | 65 | 61 | 58 | 54 | 81 |
| 82 | 96 | 92 | 88 | 84 | 80 | 76 | 72 | 69 | 65 | 62 | 58 | 55 | 82 |
| 83 | 96 | 92 | 88 | 84 | 80 | 76 | 73 | 69 | 66 | 62 | 59 | 55 | 83 |
| 84 | 96 | 92 | 88 | 84 | 80 | 77 | 73 | 69 | 66 | 63 | 59 | 56 | 84 |
| 85 | 96 | 92 | 88 | 84 | 80 | 77 | 73 | 70 | 66 | 63 | 60 | 56 | 85 |
| 86 | 96 | 92 | 88 | 84 | 81 | 77 | 73 | 70 | 67 | 63 | 60 | 57 | 86 |
| 87 | 96 | 92 | 88 | 84 | 81 | 77 | 74 | 70 | 67 | 64 | 60 | 57 | 87 |
| 88 | 96 | 92 | 88 | 85 | 81 | 77 | 74 | 71 | 67 | 64 | 61 | 58 | 88 |
| 89 | 96 | 92 | 88 | 85 | 81 | 78 | 74 | 71 | 68 | 64 | 61 | 58 | 89 |
| 90 | 96 | 92 | 88 | 85 | 81 | 78 | 75 | 71 | 68 | 65 | 62 | 59 | 90 |
| 91 | 96 | 92 | 89 | 85 | 82 | 78 | 75 | 71 | 68 | 65 | 62 | 59 | 91 |
| 92 | 96 | 92 | 89 | 85 | 82 | 78 | 75 | 72 | 69 | 65 | 62 | 59 | 92 |
| 93 | 96 | 93 | 89 | 85 | 82 | 78 | 75 | 72 | 69 | 66 | 63 | 60 | 93 |
| 94 | 96 | 93 | 89 | 86 | 82 | 79 | 75 | 72 | 69 | 66 | 63 | 60 | 94 |
| 95 | 96 | 93 | 89 | 86 | 82 | 79 | 76 | 72 | 69 | 66 | 63 | 60 | 95 |
| 96 | 96 | 93 | 89 | 86 | 82 | 79 | 76 | 73 | 70 | 67 | 64 | 61 | 96 |
| 97 | 96 | 93 | 89 | 86 | 82 | 79 | 76 | 73 | 70 | 67 | 64 | 61 | 97 |
| 98 | 96 | 93 | 89 | 86 | 83 | 79 | 76 | 73 | 70 | 67 | 64 | 61 | 98 |
| 99 | 96 | 93 | 89 | 86 | 83 | 80 | 76 | 73 | 70 | 68 | 65 | 62 | 99 |
| 100 | 97 | 93 | 90 | 86 | 83 | 80 | 77 | 74 | 71 | 68 | 65 | 62 | 100 |
| 101 | 97 | 93 | 90 | 86 | 83 | 80 | 77 | 74 | 71 | 68 | 65 | 62 | 101 |
| 102 | 97 | 93 | 90 | 86 | 83 | 80 | 77 | 74 | 71 | 68 | 65 | 63 | 102 |
| 103 | 97 | 93 | 90 | 87 | 83 | 80 | 77 | 74 | 71 | 69 | 66 | 63 | 103 |
| 104 | 97 | 93 | 90 | 87 | 83 | 80 | 77 | 74 | 72 | 69 | 66 | 63 | 104 |
| 105 | 97 | 93 | 90 | 87 | 84 | 81 | 78 | 75 | 72 | 69 | 66 | 64 | 105 |
| 106 | 97 | 93 | 90 | 87 | 84 | 81 | 78 | 75 | 72 | 69 | 66 | 64 | 106 |
| 107 | 97 | 93 | 90 | 87 | 84 | 81 | 78 | 75 | 72 | 69 | 67 | 64 | 107 |
| 108 | 97 | 93 | 90 | 87 | 84 | 81 | 78 | 75 | 72 | 70 | 67 | 64 | 108 |
| 109 | 97 | 93 | 90 | 87 | 84 | 81 | 78 | 75 | 73 | 70 | 67 | 65 | 109 |
| 110 | 97 | 94 | 90 | 87 | 84 | 81 | 78 | 76 | 73 | 70 | 67 | 65 | 110 |
| t. | 1°.0 | 2°.0 | 3°.0 | 4°.0 | 5°.0 | 6°.0 | 7°.0 | 8°.0 | 9°.0 | 10°.0 | 11°.0 | 12°.0 | t. |
Table II.—Relative Humidity, per cent.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 12°.0 | 13°.0 | 14°.0 | 15°.0 | 16°.0 | 17°.0 | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | (Dry ther.) |
| 80 | 54 | 51 | 47 | 44 | 41 | 38 | 35 | 32 | 29 | 26 | 23 | 20 | 18 | 80 |
| 81 | 54 | 51 | 48 | 44 | 41 | 38 | 35 | 33 | 30 | 27 | 24 | 21 | 19 | 81 |
| 82 | 55 | 52 | 48 | 45 | 42 | 39 | 36 | 33 | 31 | 28 | 25 | 22 | 20 | 82 |
| 83 | 55 | 52 | 49 | 46 | 43 | 40 | 37 | 34 | 31 | 29 | 26 | 23 | 21 | 83 |
| 84 | 56 | 53 | 49 | 46 | 44 | 41 | 38 | 35 | 32 | 29 | 27 | 24 | 22 | 84 |
| 85 | 56 | 53 | 50 | 47 | 44 | 41 | 38 | 36 | 33 | 30 | 28 | 25 | 22 | 85 |
| 86 | 57 | 54 | 51 | 48 | 45 | 42 | 39 | 36 | 34 | 31 | 29 | 26 | 23 | 86 |
| 87 | 57 | 54 | 51 | 48 | 45 | 42 | 40 | 37 | 34 | 32 | 30 | 27 | 24 | 87 |
| 88 | 58 | 55 | 52 | 49 | 46 | 43 | 40 | 38 | 35 | 32 | 30 | 27 | 25 | 88 |
| 89 | 58 | 55 | 52 | 49 | 46 | 44 | 41 | 38 | 36 | 33 | 31 | 28 | 26 | 89 |
| 90 | 59 | 56 | 53 | 50 | 47 | 44 | 41 | 39 | 36 | 34 | 32 | 29 | 26 | 90 |
| 91 | 59 | 56 | 53 | 50 | 47 | 45 | 42 | 39 | 37 | 35 | 33 | 30 | 27 | 91 |
| 92 | 59 | 56 | 54 | 51 | 48 | 45 | 43 | 40 | 37 | 35 | 33 | 30 | 28 | 92 |
| 93 | 60 | 57 | 54 | 51 | 48 | 46 | 43 | 41 | 38 | 36 | 34 | 31 | 29 | 93 |
| 94 | 60 | 57 | 54 | 52 | 49 | 46 | 44 | 41 | 39 | 36 | 34 | 31 | 29 | 94 |
| 95 | 60 | 58 | 55 | 52 | 49 | 47 | 44 | 42 | 39 | 37 | 35 | 32 | 30 | 95 |
| 96 | 61 | 58 | 55 | 53 | 50 | 47 | 45 | 42 | 40 | 37 | 36 | 33 | 30 | 96 |
| 97 | 61 | 58 | 56 | 53 | 50 | 48 | 45 | 43 | 40 | 38 | 36 | 33 | 31 | 97 |
| 98 | 61 | 59 | 56 | 53 | 51 | 48 | 46 | 43 | 41 | 38 | 37 | 34 | 32 | 98 |
| 99 | 62 | 59 | 56 | 54 | 51 | 49 | 46 | 44 | 41 | 39 | 37 | 34 | 32 | 99 |
| 100 | 62 | 59 | 57 | 54 | 51 | 49 | 47 | 44 | 42 | 39 | 37 | 35 | 33 | 100 |
| 101 | 62 | 60 | 57 | 54 | 52 | 49 | 47 | 45 | 42 | 40 | 38 | 36 | 33 | 101 |
| 102 | 63 | 60 | 57 | 55 | 52 | 50 | 47 | 45 | 43 | 40 | 38 | 36 | 34 | 102 |
| 103 | 63 | 60 | 58 | 55 | 53 | 50 | 48 | 45 | 43 | 41 | 39 | 37 | 34 | 103 |
| 104 | 63 | 61 | 58 | 55 | 53 | 51 | 48 | 46 | 44 | 41 | 39 | 37 | 35 | 104 |
| 105 | 64 | 61 | 58 | 56 | 53 | 51 | 49 | 46 | 44 | 42 | 40 | 38 | 35 | 105 |
| 106 | 64 | 61 | 59 | 56 | 54 | 51 | 49 | 47 | 44 | 42 | 40 | 38 | 36 | 106 |
| 107 | 64 | 62 | 59 | 57 | 54 | 52 | 49 | 47 | 45 | 43 | 41 | 38 | 36 | 107 |
| 108 | 64 | 62 | 59 | 57 | 54 | 52 | 50 | 47 | 45 | 43 | 41 | 39 | 37 | 108 |
| 109 | 65 | 62 | 60 | 57 | 55 | 52 | 50 | 48 | 46 | 44 | 41 | 39 | 37 | 109 |
| 110 | 65 | 62 | 60 | 57 | 55 | 53 | 50 | 48 | 46 | 44 | 42 | 40 | 38 | 110 |
| t. | 12°.0 | 13°.0 | 14°.0 | 15°.0 | 16°.0 | 17°.0 | 18°.0 | 19°.0 | 20°.0 | 21°.0 | 22°.0 | 23°.0 | 24°.0 | t. |
Table II.—Relative Humidity, per cent.
| t | Difference between the dry and wet thermometers (t-t'). | t |
| (Dry ther.) | 36°.0 | 37°.0 | 38°.0 | 39°.0 | 40°.0 | 41°.0 | 42°.0 | 43°.0 | 44°.0 | 45°.0 | 46°.0 | 48°.0 | (Dry ther.) |
| 89 | 1 | | | | | | | | | | | | 89 |
| 90 | 2 | | | | | | | | | | | | 90 |
| 91 | 3 | 1 | | | | | | | | | | | 91 |
| 92 | 3 | 2 | 1 | | | | | | | | | | 92 |
| 93 | 4 | 3 | 2 | | | | | | | | | | 93 |
| 94 | 5 | 4 | 3 | 0 | | | | | | | | | 94 |
| 95 | 6 | 5 | 4 | 1 | | | | | | | | | 95 |
| 96 | 7 | 5 | 5 | 2 | 1 | | | | | | | | 96 |
| 97 | 8 | 6 | 6 | 3 | 1 | | | | | | | | 97 |
| 98 | 9 | 7 | 7 | 4 | 2 | 1 | | | | | | | 98 |
| 99 | 10 | 8 | 7 | 5 | 3 | 2 | 0 | | | | | | 99 |
| 100 | 10 | 9 | 8 | 6 | 4 | 3 | 1 | | | | | | 100 |
| 101 | 11 | 9 | 9 | 6 | 5 | 3 | 2 | 0 | | | | | 101 |
| 102 | 12 | 10 | 9 | 7 | 6 | 4 | 3 | 1 | | | | | 102 |
| 103 | 12 | 11 | 9 | 8 | 6 | 5 | 4 | 2 | 1 | | | | 103 |
| 104 | 13 | 12 | 10 | 8 | 7 | 6 | 5 | 3 | 2 | | | | 104 |
| 105 | 14 | 12 | 11 | 9 | 8 | 6 | 5 | 4 | 2 | 1 | | | 105 |
| 106 | 14 | 13 | 11 | 10 | 8 | 7 | 6 | 4 | 3 | 2 | 0 | | 106 |
| 107 | 15 | 14 | 12 | 11 | 9 | 8 | 6 | 5 | 4 | 3 | 1 | | 107 |
| 108 | 16 | 14 | 13 | 11 | 10 | 9 | 7 | 6 | 5 | 3 | 2 | | 108 |
| 109 | 16 | 15 | 13 | 12 | 10 | 9 | 8 | 7 | 5 | 4 | 3 | | 109 |
| 110 | 17 | 15 | 14 | 13 | 11 | 10 | 8 | 7 | 6 | 5 | 3 | 1 | 110 |
| t. | 36°.0 | 37°.0 | 38°.0 | 39°.0 | 40°.0 | 41°.0 | 42°.0 | 43°.0 | 44°.0 | 45°.0 | 46°.0 | 48°.0 | t. |
Table III.—Reduction of Barometer Reading to 32°.
| Inches. |
Temperature
°F | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 30.5 | 31.0 |
| 30 | -.003 | -.003 | -.003 | -.003 | -.003 | -.003 | -.003 | -.003 | -.003 | -.004 | -.004 | -.004 | -.004 | -.004 | -.004 |
| 31 | .005 | .005 | .005 | .005 | .006 | .006 | .006 | .006 | .006 | .006 | .006 | .006 | .006 | .007 | .007 |
| 32 | .007 | .008 | .008 | .008 | .008 | .008 | .008 | .008 | .009 | .009 | .009 | .009 | .009 | .009 | .009 |
| 33 | .010 | .010 | .010 | .010 | .010 | .010 | .011 | .011 | .011 | .011 | .012 | .012 | .012 | .012 | .012 |
| 34 | .012 | .012 | .012 | .012 | .013 | .013 | .013 | .013 | .014 | .014 | .014 | .014 | .015 | .015 | .015 |
| 35 | .014 | .014 | .014 | .015 | .015 | .015 | .016 | .016 | .016 | .016 | .017 | .017 | .017 | .018 | .018 |
| 36 | .016 | .016 | .017 | .017 | .017 | .018 | .018 | .018 | .019 | .019 | .019 | .020 | .020 | .020 | .021 |
| 37 | .018 | .019 | .019 | .019 | .020 | .020 | .021 | .021 | .021 | .022 | .022 | .022 | .023 | .023 | .024 |
| 38 | .020 | .021 | .021 | .022 | .022 | .022 | .023 | .023 | .024 | .024 | .025 | .025 | .026 | .026 | .026 |
| 39 | .023 | .023 | .024 | .024 | .024 | .025 | .025 | .026 | .026 | .027 | .027 | .028 | .028 | .029 | .029 |
| 40 | .025 | .025 | .026 | .026 | .027 | .027 | .028 | .028 | .029 | .030 | .030 | .030 | .031 | .031 | .032 |
| 41 | .027 | .027 | .028 | .029 | .029 | .030 | .030 | .031 | .031 | .032 | .033 | .033 | .034 | .034 | .035 |
| 42 | .029 | .030 | .030 | .031 | .032 | .032 | .033 | .033 | .034 | .034 | .035 | .036 | .036 | .037 | .038 |
| 43 | .031 | .032 | .033 | .033 | .034 | .035 | .035 | .036 | .036 | .037 | .038 | .038 | .039 | .040 | .040 |
| 44 | .033 | .034 | .035 | .035 | .036 | .037 | .038 | .038 | .039 | .040 | .040 | .041 | .042 | .042 | .043 |
| 45 | .036 | .037 | .037 | .038 | .039 | .039 | .040 | .041 | .042 | .042 | .043 | .044 | .045 | .045 | .046 |
| 46 | .038 | .038 | .039 | .040 | .041 | .042 | .043 | .043 | .044 | .045 | .046 | .046 | .047 | .048 | .049 |
| 47 | .040 | .041 | .042 | .042 | .043 | .044 | .045 | .046 | .047 | .048 | .048 | .049 | .050 | .051 | .052 |
| 48 | .042 | .043 | .044 | .045 | .046 | .047 | .047 | .048 | .049 | .050 | .051 | .052 | .053 | .053 | .054 |
| 49 | .044 | .045 | .046 | .047 | .048 | .049 | .050 | .051 | .052 | .052 | .054 | .054 | .055 | .056 | .057 |
| 50 | .046 | .047 | .048 | .049 | .050 | .051 | .052 | .053 | .054 | .055 | .056 | .057 | .058 | .059 | .060 |
| 51 | .049 | .050 | .051 | .052 | .053 | .054 | .055 | .056 | .057 | .058 | .059 | .060 | .061 | .062 | .063 |
| 52 | .051 | .052 | .053 | .054 | .055 | .056 | .057 | .058 | .059 | .060 | .061 | .062 | .064 | .065 | .066 |
| 53 | .053 | .054 | .055 | .056 | .057 | .058 | .060 | .061 | .062 | .063 | .064 | .065 | .066 | .067 | .068 |
| 54 | .055 | .056 | .057 | .058 | .060 | .061 | .062 | .063 | .064 | .065 | .067 | .068 | .069 | .070 | .071 |
| 55 | .057 | .058 | .060 | .061 | .062 | .063 | .064 | .065 | .066 | .068 | .069 | .070 | .071 | .073 | .074 |
| 56 | .060 | .061 | .062 | .063 | .064 | .065 | .067 | .068 | .069 | .070 | .072 | .073 | .074 | .075 | .077 |
| 57 | .062 | .063 | .064 | .065 | .067 | .068 | .069 | .070 | .072 | .073 | .075 | .076 | .077 | .078 | .080 |
| 58 | .064 | .065 | .066 | .068 | .069 | .070 | .071 | .073 | .074 | .076 | .077 | .078 | .080 | .081 | .082 |
| 59 | .066 | .068 | .069 | .070 | .072 | .073 | .074 | .075 | .077 | .078 | .080 | .081 | .083 | .084 | .085 |
| 60 | .068 | .070 | .071 | .072 | .074 | .076 | .077 | .078 | .079 | .081 | .082 | .084 | .085 | .086 | .088 |
| 61 | .070 | .072 | .073 | .074 | .076 | .077 | .079 | .080 | .082 | .083 | .085 | .086 | .088 | .089 | .091 |
| 62 | .073 | .074 | .076 | .077 | .079 | .080 | .082 | .083 | .085 | .086 | .088 | .089 | .091 | .092 | .094 |
| 63 | .075 | .076 | .078 | .079 | .081 | .082 | .084 | .085 | .087 | .088 | .090 | .091 | .093 | .095 | .096 |
| 64 | .077 | .078 | .080 | .081 | .083 | .085 | .086 | .088 | .090 | .091 | .093 | .094 | .096 | .097 | .099 |
| 65 | -.079 | -.080 | -.082 | -.084 | -.086 | -.087 | -.089 | -.090 | -.092 | -.093 | -.095 | -.097 | -.099 | -.100 | -.102 |
Table III.—Reduction of Barometer Reading to 32°.—Continued.
| Inches. |
| °F | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 30.5 | 31.0 |
| 65 | -.079 | -.080 | -.082 | -.084 | -.086 | -.087 | -.089 | -.090 | -.092 | -.093 | -.095 | -.097 | -.099 | -.100 | -.102 |
| 66 | .081 | .083 | .085 | .086 | .088 | .089 | .091 | .093 | .095 | .096 | .098 | .099 | .101 | .103 | .105 |
| 67 | .083 | .085 | .087 | .088 | .090 | .092 | .094 | .095 | .097 | .099 | .101 | .102 | .104 | .106 | .108 |
| 68 | .085 | .087 | .089 | .090 | .093 | .094 | .096 | .098 | .100 | .101 | .103 | .105 | .107 | .108 | .110 |
| 69 | .088 | .089 | .091 | .093 | .095 | .097 | .099 | .100 | .102 | .104 | .106 | .107 | .110 | .111 | .113 |
| 70 | .090 | .092 | .094 | .096 | .097 | .099 | .101 | .103 | .105 | .106 | .109 | .110 | .112 | .114 | .116 |
| 71 | .092 | .094 | .096 | .098 | .100 | .101 | .103 | .105 | .107 | .109 | .111 | .113 | .115 | .116 | .119 |
| 72 | .094 | .096 | .098 | .100 | .102 | .104 | .106 | .108 | .110 | .112 | .114 | .116 | .118 | .120 | .122 |
| 73 | .096 | .098 | .100 | .102 | .104 | .106 | .108 | .110 | .112 | .114 | .116 | .118 | .120 | .122 | .124 |
| 74 | .098 | .100 | .103 | .105 | .107 | .109 | .111 | .113 | .115 | .117 | .119 | .121 | .123 | .125 | .127 |
| 75 | .101 | .102 | .105 | .106 | .109 | .111 | .113 | .115 | .117 | .119 | .122 | .124 | .126 | .128 | .130 |
| 76 | .103 | .104 | .107 | .109 | .111 | .113 | .116 | .118 | .120 | .122 | .124 | .126 | .128 | .130 | .133 |
| 77 | .105 | .107 | .109 | .111 | .114 | .116 | .118 | .120 | .122 | .124 | .127 | .129 | .131 | .133 | .136 |
| 78 | .107 | .109 | .112 | .113 | .116 | .118 | .120 | .122 | .125 | .127 | .129 | .131 | .134 | .136 | .138 |
| 79 | .109 | .111 | .114 | .116 | .118 | .120 | .123 | .125 | .127 | .129 | .132 | .134 | .137 | .139 | .141 |
| 80 | .111 | .113 | .116 | .118 | .121 | .123 | .125 | .127 | .130 | .132 | .135 | .137 | .139 | .141 | .144 |
| 81 | .114 | .116 | .118 | .120 | .123 | .125 | .128 | .130 | .132 | .134 | .137 | .139 | .142 | .144 | .147 |
| 82 | .116 | .118 | .121 | .122 | .125 | .128 | .130 | .132 | .135 | .137 | .140 | .142 | .145 | .147 | .149 |
| 83 | .118 | .120 | .123 | .125 | .128 | .130 | .133 | .135 | .138 | .140 | .142 | .145 | .147 | .149 | .152 |
| 84 | .120 | .122 | .125 | .127 | .130 | .132 | .135 | .138 | .140 | .142 | .145 | .147 | .150 | .152 | .155 |
| 85 | .122 | .124 | .127 | .129 | .132 | .134 | .137 | .139 | .143 | .145 | .148 | .150 | .153 | .155 | .158 |
| 86 | .124 | .126 | .128 | .130 | .135 | .137 | .140 | .143 | .145 | .148 | .150 | .153 | .155 | .158 | .161 |
| 87 | .126 | .129 | .132 | .134 | .137 | .139 | .142 | .144 | .148 | .150 | .153 | .155 | .158 | .161 | .163 |
| 88 | .129 | .131 | .134 | .137 | .139 | .142 | .145 | .147 | .150 | .152 | .155 | .158 | .161 | .163 | .166 |
| 89 | .131 | .133 | .136 | .139 | .142 | .144 | .147 | .150 | .153 | .155 | .158 | .161 | .164 | .166 | .169 |
| 90 | .133 | .136 | .138 | .141 | .144 | .147 | .150 | .153 | .155 | .157 | .161 | .164 | .166 | .169 | .172 |
| 91 | .135 | .138 | .141 | .143 | .146 | .149 | .152 | .155 | .158 | .160 | .163 | .166 | .169 | .172 | .175 |
| 92 | .137 | .140 | .143 | .146 | .149 | .152 | .154 | .157 | .160 | .163 | .166 | .169 | .172 | .175 | .177 |
| 93 | .139 | .142 | .145 | .148 | .151 | .154 | .157 | .160 | .163 | .166 | .168 | .171 | .174 | .177 | .180 |
| 94 | .142 | .145 | .147 | .150 | .153 | .156 | .159 | .162 | .165 | .168 | .171 | .174 | .177 | .180 | .183 |
| 95 | .144 | .147 | .150 | .153 | .156 | .159 | .162 | .165 | .168 | .171 | .174 | .177 | .180 | .183 | .186 |
| 96 | .146 | .149 | .152 | .155 | .158 | .161 | .164 | .167 | .170 | .173 | .176 | .179 | .182 | .185 | .188 |
| 97 | .148 | .151 | .154 | .157 | .160 | .164 | .167 | .170 | .173 | .176 | .179 | .182 | .185 | .188 | .191 |
| 98 | .150 | .153 | .156 | .160 | .163 | .166 | .169 | .172 | .175 | .178 | .181 | .185 | .188 | .191 | .194 |
| 99 | .152 | .155 | .159 | .162 | .165 | .168 | .171 | .175 | .178 | .181 | .184 | .187 | .190 | .194 | .197 |
| 100 | -.154 | -.157 | -.161 | -.164 | -.167 | -.171 | -.174 | -.177 | -.180 | -.184 | -.187 | -.190 | -.193 | -.197 | -.200 |
Table IV.—For Reducing Observations of the Barometer to Sea
Level.—Continued.
| Height, in feet. | Temperature of external air—degrees Fahrenheit. |
| -20° | -10° | 0° | 10° | 20° | 30° | 40° | 50° | 60° | 70° | 80° | 90° | 100° |
| 550 | .704 | .687 | .670 | .655 | .640 | .626 | .613 | .600 | .587 | .575 | .564 | .553 | .542 |
| 560 | .717 | .699 | .683 | .667 | .652 | .638 | .624 | .611 | .598 | .586 | .574 | .563 | .552 |
| 570 | .729 | .712 | .695 | .679 | .663 | .649 | .635 | .622 | .608 | .596 | .584 | .573 | .562 |
| 580 | .742 | .724 | .707 | .690 | .675 | .660 | .646 | .632 | .619 | .606 | .595 | .583 | .571 |
| 590 | .754 | .737 | .719 | .702 | .686 | .672 | .657 | .643 | .629 | .617 | .605 | .593 | .581 |
| 600 | .767 | .749 | .731 | .714 | .698 | .683 | .668 | .654 | .640 | .627 | .615 | .603 | .591 |
| 610 | .780 | .761 | .743 | .726 | .709 | .694 | .679 | .665 | .650 | .637 | .625 | .613 | .601 |
| 620 | .792 | .774 | .755 | .738 | .721 | .705 | .690 | .675 | .661 | .648 | .635 | .623 | .611 |
| 630 | .805 | .786 | .767 | .749 | .732 | .717 | .701 | .686 | .671 | .658 | .645 | .633 | .620 |
| 640 | .817 | .798 | .779 | .761 | .744 | .728 | .712 | .697 | .682 | .668 | .655 | .643 | .630 |
| 650 | .830 | .811 | .791 | .773 | .755 | .739 | .723 | .708 | .692 | .679 | .666 | .653 | .640 |
| 660 | .843 | .823 | .803 | .785 | .767 | .750 | .734 | .718 | .703 | .689 | .676 | .662 | .650 |
| 670 | .855 | .835 | .815 | .797 | .778 | .761 | .745 | .729 | .713 | .699 | .686 | .672 | .660 |
| 680 | .868 | .847 | .827 | .808 | .790 | .773 | .756 | .740 | .724 | .709 | .696 | .682 | .669 |
| 690 | .880 | .860 | .839 | .820 | .801 | .784 | .767 | .750 | .734 | .720 | .706 | .692 | .679 |
| 700 | .893 | .872 | .851 | .832 | .813 | .795 | .778 | .761 | .745 | .730 | .716 | .702 | .689 |
| 710 | .905 | .884 | .863 | .844 | .824 | .806 | .789 | .772 | .755 | .740 | .726 | .712 | .698 |
| 720 | .918 | .896 | .875 | .855 | .836 | .817 | .800 | .782 | .766 | .751 | .736 | .722 | .708 |
| 730 | .930 | .909 | .887 | .867 | .847 | .829 | .811 | .793 | .776 | .761 | .746 | .732 | .718 |
| 740 | .943 | .921 | .899 | .879 | .859 | .840 | .822 | .804 | .787 | .771 | .756 | .742 | .728 |
| 750 | .955 | .933 | .911 | .891 | .870 | .851 | .833 | .815 | .797 | .782 | .767 | .752 | .738 |
| 760 | .968 | .945 | .922 | .902 | .881 | .862 | .843 | .825 | .808 | .792 | .777 | .761 | .747 |
| 770 | .980 | .957 | .934 | .914 | .893 | .873 | .854 | .836 | .818 | .802 | .787 | .771 | .757 |
| 780 | .993 | .970 | .946 | .926 | .904 | .885 | .865 | .847 | .829 | .812 | .797 | .781 | .767 |
| 790 | 1.005 | .982 | .958 | .937 | .916 | .896 | .876 | .857 | .839 | .823 | .807 | .791 | .776 |
| 800 | 1.018 | .994 | .970 | .949 | .927 | .907 | .887 | .868 | .850 | .833 | .817 | .801 | .786 |
| 810 | 1.030 | 1.006 | .982 | .961 | .938 | .918 | .898 | .878 | .860 | .843 | .827 | .811 | .796 |
| 820 | 1.043 | 1.018 | .994 | .972 | .950 | .929 | .909 | .889 | .871 | .854 | .937 | .821 | .805 |
| 830 | 1.055 | 1.031 | 1.006 | .984 | .961 | .940 | .920 | .900 | .881 | .864 | .847 | .831 | .815 |
| 840 | 1.068 | 1.043 | 1.018 | .995 | .973 | .951 | .931 | .911 | .892 | .874 | .857 | .841 | .825 |
| 850 | 1.080 | 1.055 | 1.030 | 1.007 | .984 | .962 | .942 | .922 | .902 | .885 | .867 | .851 | .835 |
| 860 | 1.093 | 1.067 | 1.041 | 1.019 | .995 | .974 | .952 | .932 | .913 | .895 | .877 | .860 | .844 |
| 870 | 1.105 | 1.079 | 1.053 | 1.030 | 1.007 | .985 | .963 | .943 | .923 | .905 | .887 | .870 | .854 |
| 880 | 1.118 | 1.092 | 1.065 | 1.042 | 1.018 | .996 | .974 | .954 | .934 | .915 | .897 | .880 | .864 |
| 890 | 1.130 | 1.104 | 1.077 | 1.053 | 1.030 | 1.007 | .985 | .904 | .944 | .926 | .907 | .890 | .873 |
| 900 | 1.143 | 1.116 | 1.089 | 1.065 | 1.041 | 1.018 | .996 | .975 | .955 | .936 | .917 | .900 | .883 |
| 910 | 1.155 | 1.128 | 1.101 | 1.077 | 1.052 | 1.029 | 1.007 | .986 | .965 | .946 | .927 | .910 | .893 |
| 920 | 1.168 | 1.140 | 1.113 | 1.088 | 1.064 | 1.040 | 1.018 | .996 | .976 | .956 | .937 | .920 | .902 |
| 930 | 1.180 | 1.152 | 1.125 | 1.100 | 1.075 | 1.051 | 1.029 | 1.007 | .986 | .967 | .947 | .929 | .912 |
| 940 | 1.193 | 1.164 | 1.137 | 1.111 | 1.086 | 1.062 | 1.040 | 1.017 | .997 | .977 | .957 | .939 | .921 |
| 950 | 1.205 | 1.177 | 1.149 | 1.123 | 1.098 | 1.074 | 1.051 | 1.028 | 1.007 | .987 | .967 | .949 | .931 |
| 960 | 1.217 | 1.189 | 1.160 | 1.135 | 1.109 | 1.085 | 1.061 | 1.039 | 1.017 | .997 | .977 | .959 | .941 |
| 970 | 1.230 | 1.201 | 1.172 | 1.146 | 1.120 | 1.096 | 1.072 | 1.049 | 1.028 | 1.007 | .987 | .969 | .950 |
| 980 | 1.242 | 1.213 | 1.184 | 1.158 | 1.131 | 1.107 | 1.083 | 1.060 | 1.038 | 1.018 | .997 | .978 | .960 |
| 990 | 1.255 | 1.225 | 1.196 | 1.169 | 1.143 | 1.118 | 1.094 | 1.070 | 1.049 | 1.028 | 1.007 | .988 | .969 |
| 1000 | 1.267 | 1.237 | 1.208 | 1.181 | 1.154 | 1.129 | 1.105 | 1.081 | 1.059 | 1.038 | 1.017 | .998 | .979 |
| 1010 | 1.279 | 1.249 | 1.220 | 1.192 | 1.165 | 1.140 | 1.116 | 1.092 | 1.069 | 1.048 | 1.027 | 1.008 | .989 |
| 1020 | 1.292 | 1.261 | 1.232 | 1.204 | 1.177 | 1.151 | 1.127 | 1.102 | 1.080 | 1.058 | 1.037 | 1.018 | .998 |
| 1030 | 1.304 | 1.273 | 1.243 | 1.215 | 1.188 | 1.162 | 1.137 | 1.113 | 1.090 | 1.069 | 1.047 | 1.027 | 1.008 |
| 1040 | 1.317 | 1.285 | 1.255 | 1.227 | 1.199 | 1.173 | 1.148 | 1.123 | 1.101 | 1.079 | 1.057 | 1.037 | 1.017 |
| 1050 | 1.329 | 1.298 | 1.267 | 1.238 | 1.211 | 1.184 | 1.159 | 1.134 | 1.111 | 1.089 | 1.067 | 1.047 | 1.027 |
| 1060 | 1.341 | 1.310 | 1.279 | 1.250 | 1.222 | 1.195 | 1.170 | 1.145 | 1.121 | 1.099 | 1.077 | 1.057 | 1.037 |
| 1070 | 1.354 | 1.322 | 1.291 | 1.261 | 1.233 | 1.206 | 1.181 | 1.155 | 1.132 | 1.109 | 1.087 | 1.067 | 1.046 |
| 1080 | 1.366 | 1.334 | 1.302 | 1.273 | 1.244 | 1.217 | 1.191 | 1.166 | 1.142 | 1.120 | 1.097 | 1.076 | 1.056 |
| 1090 | 1.379 | 1.346 | 1.314 | 1.284 | 1.256 | 1.228 | 1.202 | 1.176 | 1.153 | 1.130 | 1.107 | 1.086 | 1.065 |
Table IV.—For Reducing Observations of the Barometer to Sea
Level.—Continued.
| Height, in feet. | Temperature of external air—degrees Fahrenheit. |
| -20° | -10° | 0° | 10° | 20° | 30° | 40° | 50° | 60° | 70° | 80° | 90° | 100° |
| 1100 | 1.391 | 1.358 | 1.326 | 1.296 | 1.267 | 1.239 | 1.213 | 1.187 | 1.163 | 1.140 | 1.117 | 1.096 | 1.075 |
| 1110 | 1.403 | 1.370 | 1.338 | 1.307 | 1.278 | 1.250 | 1.224 | 1.198 | 1.173 | 1.150 | 1.127 | 1.106 | 1.085 |
| 1120 | 1.416 | 1.382 | 1.350 | 1.319 | 1.289 | 1.261 | 1.235 | 1.208 | 1.184 | 1.160 | 1.137 | 1.115 | 1.094 |
| 1130 | 1.428 | 1.394 | 1.361 | 1.330 | 1.301 | 1.272 | 1.245 | 1.219 | 1.194 | 1.170 | 1.147 | 1.125 | 1.104 |
| 1140 | 1.440 | 1.406 | 1.373 | 1.342 | 1.312 | 1.283 | 1.256 | 1.229 | 1.204 | 1.180 | 1.157 | 1.135 | 1.113 |
| 1150 | 1.453 | 1.418 | 1.385 | 1.353 | 1.323 | 1.294 | 1.267 | 1.240 | 1.215 | 1.191 | 1.167 | 1.145 | 1.123 |
| 1160 | 1.465 | 1.430 | 1.397 | 1.365 | 1.334 | 1.305 | 1.278 | 1.251 | 1.225 | 1.201 | 1.177 | 1.154 | 1.133 |
| 1170 | 1.477 | 1.442 | 1.409 | 1.376 | 1.345 | 1.315 | 1.289 | 1.261 | 1.235 | 1.211 | 1.187 | 1.164 | 1.142 |
| 1180 | 1.489 | 1.454 | 1.420 | 1.388 | 1.357 | 1.327 | 1.299 | 1.272 | 1.245 | 1.221 | 1.197 | 1.174 | 1.152 |
| 1190 | 1.502 | 1.466 | 1.432 | 1.399 | 1.368 | 1.338 | 1.310 | 1.282 | 1.256 | 1.231 | 1.207 | 1.183 | 1.161 |
| 1200 | 1.514 | 1.478 | 1.444 | 1.411 | 1.379 | 1.349 | 1.321 | 1.293 | 1.266 | 1.241 | 1.217 | 1.193 | 1.171 |
| 1210 | 1.526 | 1.490 | 1.456 | 1.422 | 1.390 | 1.360 | 1.332 | 1.303 | 1.276 | 1.251 | 1.227 | 1.203 | 1.180 |
| 1220 | 1.539 | 1.502 | 1.467 | 1.434 | 1.401 | 1.371 | 1.342 | 1.314 | 1.288 | 1.261 | 1.237 | 1.212 | 1.190 |
| 1230 | 1.551 | 1.514 | 1.479 | 1.445 | 1.413 | 1.382 | 1.353 | 1.324 | 1.297 | 1.271 | 1.247 | 1.222 | 1.199 |
| 1240 | 1.563 | 1.526 | 1.491 | 1.457 | 1.424 | 1.393 | 1.364 | 1.335 | 1.307 | 1.281 | 1.257 | 1.232 | 1.209 |
| 1250 | 1.576 | 1.538 | 1.502 | 1.468 | 1.435 | 1.404 | 1.374 | 1.345 | 1.317 | 1.291 | 1.266 | 1.242 | 1.218 |
| 1260 | 1.588 | 1.550 | 1.514 | 1.479 | 1.446 | 1.415 | 1.385 | 1.356 | 1.328 | 1.302 | 1.276 | 1.251 | 1.228 |
| 1270 | 1.600 | 1.562 | 1.526 | 1.491 | 1.457 | 1.426 | 1.396 | 1.366 | 1.338 | 1.312 | 1.286 | 1.261 | 1.237 |
| 1280 | 1.612 | 1.574 | 1.538 | 1.502 | 1.469 | 1.437 | 1.407 | 1.377 | 1.348 | 1.322 | 1.296 | 1.271 | 1.247 |
| 1290 | 1.625 | 1.586 | 1.549 | 1.514 | 1.480 | 1.448 | 1.417 | 1.387 | 1.359 | 1.332 | 1.306 | 1.280 | 1.256 |
| 1300 | 1.637 | 1.598 | 1.561 | 1.525 | 1.491 | 1.459 | 1.428 | 1.398 | 1.369 | 1.342 | 1.316 | 1.290 | 1.266 |
| 1310 | 1.649 | 1.610 | 1.573 | 1.536 | 1.502 | 1.470 | 1.439 | 1.408 | 1.379 | 1.352 | 1.326 | 1.300 | 1.275 |
| 1320 | 1.661 | 1.622 | 1.584 | 1.548 | 1.513 | 1.481 | 1.449 | 1.419 | 1.390 | 1.362 | 1.336 | 1.309 | 1.285 |
| 1330 | 1.674 | 1.634 | 1.596 | 1.559 | 1.525 | 1.492 | 1.460 | 1.429 | 1.400 | 1.372 | 1.346 | 1.319 | 1.294 |
| 1340 | 1.686 | 1.640 | 1.608 | 1.571 | 1.536 | 1.503 | 1.471 | 1.440 | 1.410 | 1.382 | 1.356 | 1.329 | 1.304 |
| 1350 | 1.698 | 1.658 | 1.620 | 1.582 | 1.547 | 1.514 | 1.482 | 1.450 | 1.420 | 1.393 | 1.366 | 1.339 | 1.313 |
| 1360 | 1.710 | 1.669 | 1.631 | 1.593 | 1.558 | 1.524 | 1.492 | 1.461 | 1.431 | 1.403 | 1.375 | 1.348 | 1.323 |
| 1870 | 1.722 | 1.681 | 1.643 | 1.605 | 1.569 | 1.535 | 1.503 | 1.471 | 1.441 | 1.413 | 1.385 | 1.358 | 1.332 |
| 1380 | 1.735 | 1.693 | 1.655 | 1.616 | 1.581 | 1.546 | 1.514 | 1.482 | 1.451 | 1.423 | 1.395 | 1.368 | 1.342 |
| 1390 | 1.747 | 1.705 | 1.666 | 1.628 | 1.592 | 1.557 | 1.524 | 1.492 | 1.462 | 1.433 | 1.405 | 1.377 | 1.351 |
| 1400 | 1.759 | 1.717 | 1.678 | 1.639 | 1.603 | 1.568 | 1.535 | 1.503 | 1.472 | 1.443 | 1.415 | 1.387 | 1.361 |
| 1410 | 1.771 | 1.729 | 1.690 | 1.650 | 1.614 | 1.579 | 1.546 | 1.513 | 1.482 | 1.453 | 1.425 | 1.397 | 1.370 |
| 1420 | 1.783 | 1.741 | 1.701 | 1.662 | 1.625 | 1.590 | 1.556 | 1.524 | 1.492 | 1.463 | 1.435 | 1.406 | 1.380 |
| 1430 | 1.796 | 1.753 | 1.713 | 1.673 | 1.636 | 1.601 | 1.567 | 1.534 | 1.503 | 1.473 | 1.444 | 1.416 | 1.389 |
| 1440 | 1.808 | 1.765 | 1.724 | 1.685 | 1.047 | 1.612 | 1.577 | 1.545 | 1.513 | 1.483 | 1.454 | 1.426 | 1.399 |
| 1450 | 1.820 | 1.777 | 1.736 | 1.696 | 1.658 | 1.623 | 1.588 | 1.555 | 1.523 | 1.493 | 1.464 | 1.436 | 1.408 |
| 1460 | 1.832 | 1.788 | 1.748 | 1.707 | 1.670 | 1.633 | 1.599 | 1.565 | 1.533 | 1.503 | 1.474 | 1.445 | 1.418 |
| 1470 | 1.844 | 1.800 | 1.759 | 1.719 | 1.081 | 1.644 | 1.609 | 1.576 | 1.543 | 1.513 | 1.484 | 1.455 | 1.427 |
| 1480 | 1.857 | 1.812 | 1.771 | 1.730 | 1.692 | 1.655 | 1.620 | 1.586 | 1.554 | 1.523 | 1.493 | 1.465 | 1.437 |
| 1490 | 1.869 | 1.824 | 1.782 | 1.742 | 1.703 | 1.666 | 1.630 | 1.597 | 1.564 | 1.533 | 1.503 | 1.474 | 1.446 |
| 1500 | 1.881 | 1.836 | 1.794 | 1.753 | 1.714 | 1.677 | 1.641 | 1.607 | 1.574 | 1.543 | 1.513 | 1.484 | 1.456 |
