  MISCELLANEOUS SURVEYORS' AND ENGINEERS' INSTRUMENTS, APPLIANCES, AND ACCESSORIES—CROSS STAFF—MECHANICS' LEVELS AND CLINOMETERS—BONING RODS—FOOTNER'S RAILWAY GAUGE—GIRTH STRAP FOR TIMBER MEASUREMENT—GIRTH TAPES—TIMBER MARKER—SLASHING KNIFE—BILL-HOOK—RECONNOITRING GLASS—TELESCOPE—SUN SPECTACLES—WHISTLES—PIONEER TOOLS—SKETCH BLOCK BOOK—CAMERA—GEOLOGICAL TOOLS—WEALEMEFNA—OPISOMETER—BOUCHER'S CALCULATOR—SLIDE RULES—FULLER'S CALCULATOR—ENGINEERS' POCKET BOOKS—CHRONOMETER—OUTFITS. 846.—Cross Staff.—Those of Tycho BrahÉ and of Gunter were very elaborate affairs, consisting of a pair of notched cross-bars sliding on a divided rod which gave directions to form any angle in a quadrant from the eye by sliding the bars further from or nearer to it. The surveying cross staff, after better instruments were invented to take angles, became a cross at right angles, sawn upon a disc of wood and supported upon a staff which was pressed into the ground. This was used by looking along the saw cuts to take offsets to the chain, and for setting out buildings. The fixed cross-head was much improved by making it a cross of metal with turned-up ends, down the centre of which vertical saw cuts were made at right angles, Fig. 400. This, in the author's opinion, is still the best form. 847.—Cylindrical heads superseded the open cross-head. Fig. 400.—Open cross-head. Fig. 401.—French form. Fig. 402.—Adjustable cross staff head. Larger image 848.—Adjustable Cross Staff Head.—The cross staff head is sometimes made cylindrical, in two parts, Fig. 402. The upper part is centred upon the lower so that the upper series of sights move to any angle in relation to the lower. In this construction a wheel is cut about the axis of the upper part, which works into a pinion in the lower part, so that the upper part may be revolved horizontally by it. The meeting planes of the two cylinders are divided, the lower into degrees and the upper with a vernier. The vernier is almost an unnecessary refinement, as the sighting distance from slit to hair is only about three inches, and no very great exactness can be obtained in the sighting. This instrument has commonly a magnetic compass upon the upper surface. It is about as expensive as the semi-circumferenter, shown Fig. 232, p. 347, Many of the following articles, briefly described, may be beyond the direct province of this work; but the utility of these implements for completing the equipment of a surveyor or engineer for special work it is hoped will be sufficient apology for their introduction. The subject can scarcely be treated except in a desultory manner. 849.—Mechanics' Levels.—In crowded Eastern cities, in levelling through close passages, in many cases the surveyor has to resort to mechanical levelling to carry his levels through. Mechanics' levels are too well known to need much description. The ordinary good kinds are made from 6 inches to 18 inches long, generally of rosewood, as this wood is very hard and stands well. They have a brass plate at the top, and tips of the same metal at the base. The illustration, Fig. 403, is of a 12-inch level. The level tube, which is of blown glass, is fixed in plaster of Paris, and the upper plate screwed down over it. Figs. 403, 404.—Mechanics' Levels. Larger image 850.—The Author's Hand Level is shown Fig. 404—12 inch. This is made of a casting either of iron or brass. The level tube is ground to curvature and is somewhat superior to the ordinary run of this class of work. The level tube is fitted with ball socket at one end and stiff spring fitting These levels are commonly fixed upon a stout fir straight-edge of about 5 feet to 10 feet in length by the lugs at the ends. The level is taken by blockings upon the ground. Corrections of error, both in level and straight-edge, may be made for any considerable distance by reversing the forward and backward position of the level with its straight-edge alternately. 851.—Square Level—Circular Level.—Fig. 405 represents a very useful class of level for setting up some instrument stands, plane tables, etc., in which a pair of level tubes are placed at right angles to each other. It is generally made very small—1½ inches square only. A circular level, the upper surface of which is formed of a worked concave glass, was lately very popular, and is still used to a small extent. As the spirit cannot be hermetically sealed in, it evaporates, and this level soon fails. Mr. J. J. Hicks has taken out a patent for a hermetically sealed circular level, described p. 96, which appears to answer very well. Fig. 405.—Square level. Fig. 406.—Surface level and clinometer. Larger image 852.—Incline Level.—For laying railway rails and drainage works the bubble is frequently made adjustable by the tube in which it is contained being hinged at one end and fitted in slides to rise with a screw at the other end, as shown Fig. 406. A scale of percentage of inclination S is commonly divided upon the adjustable end. The tube is raised or Fig. 407.—Stanley's sight for mechanics' levels. Larger image Fig. 408.—Section. Larger image 853.—Sighted Levels.—A mechanic's level is commonly made with a hole longitudinally through it of about ½ inch diameter, closed at one end, except a small hole of 1/30 inch or so, and a cross upon a piece of glass at the other end. This plan permits a sight to be taken through it which gives an approximate level. Occasionally the same form of sight as that described is hinged on the top surface at each end of the level. The author has found a better plan of sighting to be given by a pair of sights placed on a centre upon the ends of the level to turn up when required for use, as shown Fig. 408, P S one of the pair of points. This, when turned up, shoulders on the stop-piece A B. The stop-piece is made of sufficient thickness to admit the point in the hole near B for protection when it is folded away out of use. The section of Fig. 409.—Boning-rod. Fig. 410.—Boning-rod with standard. Larger image 854.—Boning-Rods, Fig. 409. These are very commonly employed with mechanics' levels. They are made somewhat like a stout T-square of 3 feet to 4 feet in length, about 3 inches in width, and ¾ inch in thickness both of the stem and head. They are at first placed at a distance apart, 9 or 10 feet, and a straight-edge of this length is laid from one to the other, upon which the mounted level is afterwards placed, the boning-rod being tapped down in the ground till the bubble is in the centre of its run. A third boning-rod is then placed at the same distance as the first pair, and the straight-edge with the level upon it is reversed end for end. This, if the work be fairly down, leaves the two outer boning-rods level, however imperfect the straight-edge and level may be, if the run of the bubble be taken correctly. By removing the central boning-rod from the outer pair of rods, levels may be continued by sighting over them, or boning forward as it is termed. On the Continent boning-rods are commonly fixed by driving a separate standard into the ground, which has a pair of brass slings by its side to hold the rod, Fig. 410. This Fig. 411.—Footner's railway gauge and clinometer. Larger image 855.—Railway Gauge, combining level and clinometer. This high-class gauge, Fig. 411, is the invention of Mr. H. Footner, C.E., late of the London and North-Western Railway. It is formed of a bar of Spanish mahogany neatly shaped. The end fittings are of steel. The gauging part is formed of two turn-up steel flap-pieces with back stops. A spirit level is sunk in the end fitting, shown in the figure towards the left hand. The clinometer is formed by a gun-metal pin of ½ inch in diameter; 9 inches long. This slides perpendicularly in a spring fitting sufficiently stiff to support the gauge, and is made to fall on the centre of the rail. The pin is divided into inches and eighths. When it is out of use it slides up the end of the gauge and leaves the whole instrument smooth and portable to carry open or go into a leather case. Its use is implied. 856.—Timber Girth Strap.—The direction for removal and estimate of the value of timber often falls into the hands of the surveyor. The height of standing timber may be taken by a long rod, or a pair united by a link, art. 775, or by the apomecometer, art. 693. The girth is most conveniently taken Fig. 412.—Leather girth strap with throwing reel. Larger image Some surveyors prefer a hook instead of a weight, as being more convenient to measure close timber. This is shown Fig. 413. The hook is stuck into the bark and the tree is girthed by walking round until the hook is met. Fig. 413.—Leather girth strap with clutch hook. Larger image 857.—Girth Tapes, similar to measuring tapes, Fig. 349, p. 506, are occasionally used, but these are more convenient for felled timber. Tapes for the purpose are made from ¾ inch to 1 inch wide, and 6, 12, and 24 feet long. They It is customary to allow 1 or 1½ inches, and sometimes more for bark, according to the species of tree and the custom of the country. 858.—Marking off Timber.—For this a special tool with a gouge point, Fig. 414, and strong buck-horn handle, termed a timber-marker, is used for standing timber intended to be felled. The contents of the tree are sometimes marked with the marker upon it if for sale, good bark allowance being made in cases of difficulty of extraction from the forest, etc. A plain knife is usually put with the marker, which is useful as a food knife. Fig. 414.—Timber marker, nearly full size. Larger image 859.—The author makes a very small, neat surveyor's knife, with marker, for the waistcoat pocket, Fig. 415, which combines—M tree marker (small); S screw-driver for small screws of instruments; P tommy-pin for turning capstan heads; F file for sharpening lead of pencil, when this is used for the field-book; and E R two penknife blades. The knife is similar to the author's architect's knife, which is well known. The tree marker is not strong enough for constant work. Fig. 415.—Surveyor's pocket knife. Larger image 860.—Slashing Knife—Bill-Hook—Axe.—In new countries where sight way has to be obtained for the survey through forests and jungles, one or more of the tools illustrated next is most valuable as a part of the surveyor's equipment. The slashing knife, Fig. 416, which is over a yard long, wielded by a strong man will remove light brushwood very quickly. Where the wood is close and of larger growth the bill-hook, Fig. 417, is better; and with thickset timber the axe becomes necessary. The well-known Canadian axe is found to be the best. Fig. 416.—Slashing knife. Fig. 417.—Bill-hook. Larger image 861.—Hedging Gloves—Iron Hooks for Climbing Trees.—For clearing land to avoid spines hedging gloves are generally used; these are made of soft horse-hide, and although pliable resist thorns to a great extent. Clutch hooks are also very convenient to climb trees, to look forward for the easiest direction for sight way. 862.—Rods for Measuring Standing Timber.—These are generally made 25 feet long, jointed in 5 feet lengths, similar to a fishing rod, but much stiffer. The rod is set by the side of a tree to be measured and observed from a distance where the first breech cuts its length. Fig. 418.—Reconnoitring glass, India pattern. Larger image 863.—Reconnoitring Glass.—At present it is customary to use a binocular field-glass in preference to a telescope. The telescope gives greater penetration from its Fig. 419.—Army telescope. Larger image 864.—Prism Binoculars.—These will be found a great improvement on the old form of field-glasses, as owing to the optical arrangement a high power is obtained combined with a larger field of view and good illumination. Fig. 420 shows the most modern form with all refinements; hinged body, central focussing and separate focussing to suit each eye. It has a very compact and strong body, and the size magnifying 8 diameters or about 64 times weighs only 13 ozs. Fig. 420.—Stanley's prism binocular. Larger image 865.—Dome Spectacles—Bogles.—Spectacles of neutral tint are most comfortable for general wear in sunny or snowy countries. The dome or globular form is generally preferred. Where there is hot dust gauze sides are to be preferred. There is a very cheap form with gauze sides, which holds on the head by an elastic band, termed bogles. These are rather hot to the face, and the band after a time becomes sticky. The spectacle form is much better. The glasses are made in various shades to choice: some very dark or even black, the latter being made for viewing and tending arc lights. 866.—Whistles made very powerful are much used in exploring abroad to bring the party together, and for signalling generally by sound, using the Morse signals, art. 803. 867.—Pioneers' Tools.—A small set of these is often very useful to the surveyor in new forest countries. The common set consists of a claw-hammer, wood-chisel, stone-chisel, pincers, screw-driver, gimlet, and brad-awl. The leather case is 8 by 4 by 2½ inches; it weighs 1¾ lbs. with strap. This may be supplemented by a small American saw, cutting both edges, about 20 inches long, and the axe previously described, with a few pounds of wire nails. The tools serve for marking trees or rocks, erecting signals, temporary covers, etc. 868.—Sketch Block Book—Pocket Book.—In reconnoitring no better information can be given of a track than forward sketches from commanding station to station. Sketch books about 7 inches by 5 inches are generally found sufficient. The drawing-paper should be thin, and the pocket large enough to contain all the separate sheets as they are taken off by the penknife after completion from the block. The sketches may be made with pencil, or a fine fountain pen; or if the surveyor be a colourist a light box of moist colours and a water bottle will often leave pleasing sketches as reminiscences. Pocket-books with section lines to 1/8 inch or 1/10 inch scale are sometimes used to give approximate plans to scale of buildings, etc., where required, as well as the ordinary field-book record. 869.—Camera.—Recently the camera has been much used for reconnoitring. These are now made very light and portable to take ¼ plate or 3 × 3 inch films, either on rollers or in separate films. 870.—Cement Testers are made in various manners, generally to test the cohesion of the cement as a homogeneous hard body. Mr. Mann's cement tester, Fig. 421, goes on another principle—it tests the adhesion of the cement to Fig. 421.—Mann's cement tester. Larger image 871.—Watson's Improved Vicat Needle is a most refined and accurate instrument for determining the time taken by cement in setting. The cement is placed in the circular container shown in the illustration, and the weighted needle is Fig. 422.—Watson's vicat needle. Larger image 872.—Geological Tools.—Acid-bottle—Blow-pipe—Touch-stone.—Where countries are prospected for railways it often becomes important to examine the rocks, both to detect the softer rocks for cutting and to find limestone suitable for mortar. A geological hammer, weight about 2 lbs. to 3 lbs., is the ordinary tool. This, with a chisel and sailcloth bag with strap, is all the necessary appliance. In searching for limestone a small bottle of sulphuric acid sewn up in a leather case is useful. A dipper is blown on the stopper of the bottle, and a single drop of acid will detect limestone by the bubble of froth it produces. Where minerals are to be examined, a small blow-pipe apparatus is necessary. This should be accompanied by a book of instructions. Where the surveyor has not been trained to use the blow-pipe, one with constant blast should be employed. For examination for precious metals a touch-stone and two-acid bottle—sulphuric and nitric—for silver and gold, are useful. The metal is merely rubbed on the stone and the acid applied. If the metal is base the acid removes it from the surface of the stone. If precious it removes other matter and leaves it visible. 873.—Wealemefna—Opisometer.—The wealemefna is a very neat form of space runner invented by Mr. E. R. Morris, which is found a very convenient instrument for measuring distances on maps in prospecting. It is very small and light, and may be, if desired, attached to the watch-chain. It gives distances run over in inches and eighths, to be afterwards calculated to the scale of the map, Fig. 423. The opisometer for the same purpose, Fig. 424, is formed of a spur wheel at the end of an ivory handle running upon a screw. This instrument gives measurement by reversing its run upon the scale of the map. Fig. 423.—Wealemefna. Fig. 424.—Opisometer. Larger image 874.—Boucher Calculator, the invention of M. Alex. E. M. Boucher, engineer, of Paris. Fig. 425.—Boucher's calculator. Fig. 426.—Stanley-Boucher calculator. Larger image Multiplication, using the second circle of divisions from the outside of the front dial:—Bring the first factor under the fixed index, set the movable index to 1, then bring the second factor under the movable index, and the product will be found under the fixed index. Division is performed on the same scale as follows:—Bring the dividend under the fixed index, set the movable index to the divisor, then bring 1 to the movable index, and the quotient will be found under the fixed index. For proportion the second circle is also used:—Set the first factor under the fixed index and set the movable index to the second one, then the proportionate equivalent of any number brought under the former will be found at the movable index. Square roots, using the same scale:—Bring the number under either of the indices, and the square root will be found upon one of the two inner circles of the same dial. Cube root:—In this case it is necessary to first bring the 1 on the front dial under the fixed index, then set the movable index to the number, and the cube root will be found on one of the inner circles of the back or fixed dial. To use the trigonometrical dial:—Bring the needle of this dial over the angle of which the sine or tangent is required, and read upon the other dial (indicated by the needle) the natural trigonometrical line upon the inner circle, or its logarithm upon the outer circle. The book of instructions supplied with the instruments, written by Professor George Fuller, C.E., for the author, gives all directions for working and also gauge points from which calculations are made as with the slide rule. 875.—In reduction of factors of a calculation collectively Boucher's calculator may take more than one turn or less than unity. The author has added a central index to record the number of turns. This is said to be of great value for the perfection of the instrument, Fig. 426. 876.—Slide Rules, of which there are great varieties, are of too complex a nature to discuss, except very briefly, in our limited space, particularly as general descriptions have been often given. The ordinary logarithmical scales of Gunter (1619), known as Gunter's lines, are placed upon most slide rules. The arithmetical lines are lettered A, B, C, D, and E. A and B are alike: these are technically termed double radius log. lines. They are used for all processes of multiplication and division. C and D are also alike and are termed single radius log. lines. They are used together for ordinary multiplication and division, and in conjunction with A and B scales for squares and square roots. The E line, not originally a Gunter's line, but found early in the century on several rules, is termed a triple radius log. line. 877.—The Slide Rules in most general use are A. Nestler's and A. W. Faber's. Both these well-known firms make a very complete series, applicable to a great variety of technical calculations. 878.—The reviser has recently completed from the designs of the author an entirely automatic dividing engine for these rules, which is the only one in existence. A great number of slide rules are made for special purposes only: some of these are very useful to the civil engineer. 879.—Hudson's Slide Rules give strength of shafts, beams, and girders; pump duty; and computation of horse-power in engines. 880.—Honeysett's Hydraulic Slide Rule gives discharge of 881.—Tacheometrical Slide Rules with scale of sine2 and sine × cos. for calculating the horizontal equivalents and vertical heights from tacheometrical observations. These are made either for use with instruments divided sexagesimally to 360° or centesimally to 400. 882.—Sheppard's Slide Rule has duodecimal lines, double reading, for squaring and cubing timber. 883.—Young's Slide Rule is designed for squaring and valuing timber simultaneously, which operations it performs in a very expeditious manner. 884.—Essex's Slide Rule is the best for calculating the rates of velocity and discharge from sewers, water mains, channels, and culverts of different forms, as it works with all formulÆ. 885.—The Slide Rule of Prof. Geo. Fuller, C.E., Fig. 427, presents perhaps the highest present refinement of this class of rules, capable of greatly facilitating the numerous arithmetical calculations of the civil engineer. Its range is greater than most calculating machines, and besides the operations of multiplication and division, squaring and cubing, results requiring the reciprocals, powers, roots, or logarithms of numbers can be quickly and easily worked out by its use. Fig. 427.—Professor Fuller's calculating slide scale. Larger image The rule consists of an outer cylinder that can be moved up or down, and turned round upon the cylindrical axis which is held by the handle. Upon the outer cylinder a single spiral, Fig. 428.—Improved Fuller's slide rule. Larger image An additional improvement, as shown at Fig. 428, has now been effected in these instruments by adapting the case to support the rule when in use, thus overcoming the objection of being always obliged to hold it in the hand. The use of Professor Fuller's rule is, however, confined to arithmetical computations. The numerical solution of formulÆ comprising trigonometrical functions can only be performed by extracting, with considerable loss of time, the values of these functions from a book of tables. To do so requires a certain effort of mind with its consequent risk of mistakes. This limitation has restricted its use in a considerable body of calculations, such, for example, as in the computation of the co-ordinates of surveys from the lengths and bearings of their lines, a method of plotting which is very largely used by land surveyors at present; in astronomical computations; in civil and mechanical engineering, etc.; the use of logarithms being preferred on the score of speed, although the degree of accuracy attained with Professor Fuller's rule is amply sufficient in the large majority of cases. Fig. 429.—Barnard's co-ordinate spiral slide rule. Larger image 886.—The Co-ordinate Spiral Slide Rule has been designed to meet these requirements by Mr. H. O. Barnard, A.C.H., F.R.A.S., etc., Superintendent of Trigonometrical Fig. 430.—Thacher's slide rule. Larger image Although the co-ordinate spiral rule, as all varieties of slide rules, is based primarily upon the theory of logarithms, a knowledge of that theory is by no means essential to its practical use. 887.—Thacher's Slide Rule.—Fig. 430. This contains a shorter scale than Professor Fuller's, and the system is not quite so simple. Full printed instructions are given in the 888.—Pocket Sets of Chain Scales.—These are made 3, 4, 5, and 6 inch. Three of 6 inch form the ordinary set. The chain scales, if three only, are 10, 20, 30, 40, 50, and 60; if six they generally contain the same scales with feet equal to the links. An extra scale with the ordnance or other scale of the country is found also useful for measuring from maps or plans. Some civil engineers prefer the pocket scales made wide with quite square ends, to be used as offsets or for sketching. These scales are generally made in ivory and placed in a light morocco or Russia leather case. The numbers of divisions of the scales should be stamped on the ends to prevent the wrong scale being drawn from the case. Fig. 431.—Biram's anemometer. Fig. 432.—Lowne's anemometer. Larger image 889.—Anemometers are used by mining engineers for testing the ventilation of mines. The original and best known form is that of Biram, Fig. 431. This instrument is held in any current of air, and the velocity of the current is registered by the motion of oblique fans, by means of ordinary decimal gearwork on five dials giving feet and multiples by 10. Lowne's anemometer, with the author's improvements, Fig. 432, is of 890.—Books of Tables and FormulÆ.—Few British Surveyors are without Molesworth's pocket-book. This contains all the useful tables and notes of reference valuable to the civil engineer in his ordinary work—weight, 5 ozs. Many pocket-books have been written on the same plan. Hurst's pocket-book contains all matters of reference for the town surveyor among buildings. Trautwine's Civil Engineer's Pocket-book (American) is the most complete, but it is of double the weight of the Molesworth. Spon's Engineers' Tables for the Waistcoat Pocket—weight, little over ½ oz.—is a very useful little book. Of Traverse Tables both Gurden's and Boileau's are comprehensive and reliable. There are several pocket-books of Curve Tables, those of Cutler & Edge, Beazeley, and Kennedy & Hackwood being perhaps in the most general use. 891.—Technical Books—Ordnance Maps are published on special districts and subjects which are often relative to the country or the special conditions of work abroad and at home for minerals, etc. It is very useful to possess such of these as may be required, and the note is only made here as a reminder. 892.—Sling Case for Drawings.—The most convenient method of carrying maps or drawings for public works in execution is to have a solid leather case similar to a telescope case. This is best if made with the cap or lid of the same length as the body: it can then be drawn out any distance according to the length of the rolled drawing. If thought more convenient, and the map or drawings are heavy, a strap may be added to pass over the shoulder, Fig. 433. 893.—Chronometer.—This may be any form of watch with compensated escapement. At present the prices run high for this class of work; but from the simplicity and moderate certainty of compensation it does not appear that this should be necessary for the production of a fair working instrument useful for the surveyor in new countries to check his longitude. Where a good chronometer is used it is better to keep it to Greenwich time without alteration. If there is a gaining or losing rate this will most probably remain constant in equal times, so that corrections may be made pro rat for all observations until a check can be taken with certainty when arriving at a town which possesses an observatory. The quality of a chronometer is fully ascertained by having a certificate from one of our observatories, that of Kew being the most popular. Fig. 433.—Sling case for drawings. Larger image 894.—Chronograph.—For the observation of stars in transit for the purpose of taking longitude, a dead-stop watch or chronograph is most useful. This can now be had in combination with an otherwise fair going watch at a very moderate price. 895.—Outfit of a Surveyor for Work in a New Country.—The ordinary items of strong, dust-coloured woollen clothing, good boots, saddle, firearms, etc., do not come within the province of this work. The instruments he will require will depend partly upon the nature of the country and the kind of work to be done. If for prospecting only, light instruments are commonly selected—the sextant, |
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