“Having a kite of this kind, or even two and three, so that on a single wire he can keep sending them higher and higher into the atmosphere, a boy can begin what we were wont to call in Yeddo our ‘kite education.’  First, he can make himself his own weather prophet.  Self-registering thermometers are no longer very expensive.  He can wire one of these to his kite, and, by knowing the length of wire he has in hand and the amount he pays out while the kite is up, ascertain just what the air temperature is 200 feet, 500 feet, 1,000 feet, 3,000 feet above him.

[Illustration:  Box Kites]

“There are wind gauges of cheap construction, moisture gauges which will note the coming of rain, small cameras that will automatically take pictures while the kite is in the air, that may be attached to these kites, and from the work of which valuable information may be obtained.”

The following instruction for making a box kite was given in “The American Boy,” April, 1909.

“Any boy can make a box kite.  The material used may be any tough, light wood, such as spruce, cypress, bass-wood, or cedar.  Cut four pieces 42 inches in length, and sixteen pieces 18 inches in length.  The cuts show clearly how they are to be put together.  Use glue and small brads at every point.  The bridle cord is fastened 6 inches from each end of the box.  This is best done before the cloth is put on the kite.  Light cheese cloth may be used, and should be secured with glue and small brads at the last lap.  When the cloth is in place paint it with thin varnish or glue to fill up the meshes and stretch it.

“The reason why box kites made by boys have a tendency to lie down flat on the ground is that they are not proportioned correctly.  The proportions given here are correct.  The painting, decorating, and tinting are matters of personal taste and skill.”

The principle of kite flying is simple.  Air is a fluid like water, but on account of the many changes of temperature, to which it is subjected, it constantly changes its density and is found to consist of layers or strata.  These layers are not all flat and parallel, but take every variety of shape as the clouds do.  In flying a kite you simply pull it up one of those layers just as you would pull a sled or wagon up a hill.  Always run facing the wind.

Aeroplanes

Aeroplane season is now a calendar event in the boy’s life.  Many boys are engaged in building these fascinating little ships of the air.  “The Boy’s Book of Model Aeroplanes,” by Francis A. Collins, Century Co. ($1.20 net), gives complete directions how to build these marvellous new toys.  Form a club and conduct an “Aviation” meet during the season.  Spon and Chamberlain, 123 North Liberty Street, New York City, sell a complete full-sized set of drawings for building three model aeroplanes.  Price, 50 cents.

Parachutes

[Illustration:  A Parachute Idea]