The subject of windmills and weather vanes opened up a field that seemed inexhaustible, and for a while there was a perfect furore of designing and experimenting. As usual, Harry wanted to try great schemes that Ralph knew were impracticable, and it required all his diplomacy to keep the boy down to earth, on something simple and within his power to do successfully.

One of his earliest attempts was a scheme to make a windmill on the principle of a water-wheel, placed horizontally to catch the wind.

Ralph knew that it would not work, but after arguing for some time, he decided to let the youngster learn by experience. While Harry was working at his project, Ralph sketched out and made a vane which he considered an improvement on the first one. It is shown in Fig. 95; and it was made without a mill and composed of four pieces. The horizontal piece had an arrow head at the forward end. At the rear end, two pieces of ¹/₄-inch pine were fastened with two small bolts. From the point where they were bolted they curved outward as shown in the top view, and were held in that position by two small strips nailed on with brads, one on the upper and one on the lower side. The centre of gravity was found as before, and the vane pivoted to its standard.

In the meantime, Harry had found out to his own satisfaction that his water-wheel windmill would not work.

"What have you curved those ends out for?" he exclaimed on catching a sight of Ralph's vane.

"Why, to make it more sensitive to the slightest breeze. Those curves catch the wind quicker than flat surfaces; have you never noticed that on the weather bureau vanes they are always curved out like that?"

"No," said Harry. "By the way, do you know why my mill doesn't work?""I have told you about six times that a water-wheel receives the water on one side only, while your mill receives the same pressure on both sides of the centre. The two forces balance, so your mill can't very well turn. If you could cut off the wind from one side, it would go all right."

"Well, why can't I box in one side?"

"You can, but then you will have to shift it every time the wind changes. You could construct a combination mill and vane, and arrange it so that the box would be shifted by the vane, but honestly, I don't think it worth the trouble. It would be clumsy, top-heavy, and hard to balance. I have a scheme for a horizontal mill, but we will take it up later. In the meantime, let's make a happy jack windmill!"

"Happy jack?"

"That's what they call them, but we will try to be original and I propose an Indian with war clubs."

"Whew! That sounds interesting!"

Ralph's sketch of the Indian is shown in Fig. 96. The figure was sawed out of ¹/₂-inch pine, a ³/₈-inch hole bored for the arms, and a ¹/₄-inch hole bored for the dowel pivot at the feet. The arms were made of a piece of dowel, six inches long, with ³/₁₆-inch holes bored near the ends to receive the "clubs." These were whittled out of pine, each club being a propeller blade. When fastened into the dowel they formed a complete two-bladed propeller, but this was not done until the dowel had been inserted through the Indian's shoulders, and a brad driven through on each side of the body to keep the arms in place.

Harry was so anxious to see it work that he came near spoiling it, and had to be restrained by the older boy, as in making these toys a well balanced figure is very important. When it was finally finished, and placed out in the wind, the antics of the Indian made Harry laugh till the tears ran down his cheeks.

"That's the finest thing we ever made," he said. Ralph smiled. It seemed that he had heard something like that several times before.

An athlete was suggested, and a bold figure with outstretched arms was sketched, as shown in Fig. 97.

The Indian clubs he is supposed to be swinging were propeller blades, and to give them more uniform motion than in the case of the Indian, the hands were drilled and a piece of ¹/₄-inch dowel inserted. At each end of the dowel was fastened a blade which had been drilled to fit. Brads were driven through the dowel on each side of the hand to keep the clubs swinging freely.

The body and arms were cut from a piece of ¹/₂-inch pine and halved together across the chest, and after the joint was made the form of the body and the arms whittled out with a knife. The two parts were then fastened together with brads.

It was important that this figure face the wind, so into the space between the ankles was fitted the small end of a wind vane and the figure securely fastened to it with brads. The centre of gravity was then found and the whole combination pivoted on a generous piece of ¹/₄-inch dowel.

This athletic weather vane is painted in bright colours, the clubs being gilded to make them realistic Indian clubs.

"What was that scheme of yours for a horizontal windmill?" asked Harry after he had watched the athletic club swinger until he was satisfied.

"Why, to make one on the principle of the anemometer," replied Ralph.

"How do you spell it?""Never mind the spelling, it's like this," and Ralph rapidly sketched out Fig. 98.

"This is the wind gauge of the weather bureau," he explained, "and I figure we can use ordinary tin cups for the buckets. You go down to the hardware store and buy four small round bottomed tin cups while I start the woodwork."

Having secured the cups for five cents each, they cut the handles with a pair of tinners' "snips." The cut was made next to the cup at the lowest point and the handle straightened out even with the top of the cup.

Two pieces of pine, 16 inches long, ⁷/₈-inch wide, and ⁵/₈-inch thick, were halved together at the centre, where a ¹/₄-inch hole was bored straight through the joint.

A block of wood cut to the shape a was fitted over the joint, and fastened to the four arms with 1-inch brads. The ¹/₄-inch hole was now continued almost through this cap to give a long bearing for the pivot—a ten-penny wire nail with the head filed off. Two ³/₁₆-inch holes were drilled through the handle of each cup and corresponding holes through the wooden arms. The cups were made fast by passing ³/₁₆-inch bolts through cup handles and arms and tightening the nuts.This made a very strong and rigid construction and on testing it by holding the pivot in the hand out in the breeze the instrument revolved rapidly.

Altogether it was one of the most substantial and satisfactory things that they had made, but Ralph was not yet satisfied.

"We might as well have a Coney Island of our own as not," he said. "You whittle out four propellers, 4 inches long and ¹/₂ inch across, and I'll show you something," he said.

While Harry was doing this, Ralph sawed out four wooden dirigibles shown at b, 8 inches long, 3 inches across at the widest part, and ¹/₄ inch thick.

A hole was drilled through the centre of each propeller and another in the flat stern of each air-ship. The pivots for the propellers were flat-head wire nails small enough for the blades to revolve freely, but driven securely into the air-ships.

These were now fastened at the ends of the arms of the anemometer by attaching two strips of basswood to each ship by wires. The strips were to hold the ships in the proper position facing in the direction of motion, which was always the same, no matter in which direction the wind was blowing.

The upper ends of these strips were brought together, and securely fastened under one of the bolts by wires.

As the anemometer revolved, centrifugal force sent the air-ships out as far as the basswood strips would allow.

It was a very interesting fair weather toy, but the first gale, while having no effect on the anemometer other than to make it spin around at terrific speed, nearly wrecked the ships by slamming them against the standard. So the boys always took the ships off at night, and put them on again when they wanted to give an exhibition.

The propellers were gilded and the ships painted in bright colours.

A very simple vane may be made to represent a Zeppelin air-ship (Fig. 99) by cutting out a piece of white pine 2 feet long and 2¹/₂ inches wide with the ends pointed to the shape of a Gothic arch. The hole for the pivot should be bored 2 inches deep and be placed well forward of the centre. To make the vane balance, the rear portion from the pivot to the stern should be planed thin and rounded with the spokeshave.

At the stern should be a small two-bladed propeller, pivoted on a flat-head wire nail. If the stern is still too heavy, the balance can be restored by driving into the forward point a round-headed screw, or by attaching another small propeller. In fact, if the hole in this propeller is made large enough, the screw can be used as the pivot; in any event, the vane must be balanced by adding some kind of weight at the bow.

These typical forms of wind vanes will suggest others and the young woodworker should try to be original, to design new forms, ships, submarines, air-ships, etc.

One form which the boys made was especially substantial and reliable. A six-bladed mill was constructed as follows:

First: a piece of ⁷/₈-inch pine was cut to the form of a hexagon 2 inches across the points.

Second: a ¹/₄-inch hole was bored in the centre of each of the six edges and a ³/₁₆-inch hole through the centre of the hexagon. (Fig. 100.)

Third: six blades were formed from ¹/₂-inch pine 8 inches long, 2 inches wide, tapering down to 1 inch at one end.

Fourth: in the small end a ¹/₄-inch hole was bored at the centre, about an inch deep.

Fifth: the blades were tapered in thickness from ¹/₂-inch at the small end to ³/₁₆-inch at the wide end, the tapering being done on one side only, that away from the wind, the side facing the wind being perfectly flat.Sixth: dowel pins were glued securely into the holes in the hexagonal block and into the blades, the latter being turned on the dowels at an angle of about 30 degrees—¹/₃ a right angle—from the front face.

Seventh: after the glue had hardened over night, the whole mill was painted, special attention being given to covering the joint where the glue held, to prevent the rain from loosening it.

Eighth: two pieces of ¹/₄-inch white wood were cut out to the form shown at b. These were fastened to the square piece c by two small bolts.

The wide ends of the vanes were spread and fastened by two small strips of white wood, by brads as shown.

Ninth: last came the locating of the centre of gravity, after the mill had been attached by a ten-penny flat-head wire nail. The pivot was made of a similar nail into the standard, as on previous wind vanes.