Fig. 151.
THE MECHANICAL ÆROSTAT.
Make a “flyer” by attaching three vanes to a common centre, mounted perpendicularly on a pin. These vanes are segments of a circle of which the obliquity increases as they recede from the centre of motion.
Fig. 152.
A stand is made to hold it while a cord is wound round the spindle. On pulling the string, it will ascend.
The vanes must be adjusted angularly for the best effect.
ARTIFICIAL SNAKES.
String on three parallel threads a number of small wooden scales, somewhat thick in the middle, and rounded at the edges, to form a length tapering to a point, while the other end is furnished with a carved head as of a serpent. Fasten the threads so that they are moderately tight. When taken up by the middle horizontally the two ends have a tendency to sink, but being prevented by the connection, they move to one side or the other. They can also be made of flat pieces, with one thread running straight through all to form a length, and a thread to run through them all alternately on one side and the other, opposite each other. If turned, boxwood is better than ivory, which easily breaks.
