Fig. 393.—How to operate the Pin-wheel.
To Operate the pin-wheel, hold the stick in the left hand as illustrated in [Fig. 393], and then, taking a coin in the right hand, rub it vigorously across the notches. The vibration produced by rubbing the stick causes the small pin-wheel to revolve about its pin axis. The funny part of the performance is the fact that you can have perfect control over the wheel, and change the direction of its course at will, if you but master one little trick performed with the first and second fingers of the right hand. In holding the coin between the thumb and first finger of the right hand, allow the end of the first finger to extend over the top of the stick and bring the second finger close to the side of it, as shown in the illustration ([Fig. 393]). To make the wheel revolve from left to right, allow the end of the first finger to rub along the top edge of the notches; then, to reverse the direction, relieve the pressure of this finger, and press the second finger against the other edge of the notches.
At first you may not be able to make the wheel obey your commands, but with a little practice you will find it a simple matter to make it change its direction without any one noticing how you perform the magical trick.
A Brass Tack driven into the stick a little below the notches, about the point where the thumb of your left hand will strike, will add to the mystic appearance of the pin-wheel. A person invariably notices this the first thing when he sees you operate the wheel (you can make it a point to press your left thumb against the tack), and thinks he has solved the trick. But when you let him have the toy, he will soon find out that all his pressing and pulling upon the tack will have no effect upon the wheel, and beg you to "put him on" to the trick.
A Wooden Chain and Rattle has long been one of the most interesting pieces of work a boy can make with his jack-knife, and, inasmuch as the making of one requires careful cutting, the exercise is a good test of a boy's skill with this handy tool.
Figs. 394-396.
Details of a Wooden Chain and Rattle.
In making the first chain and rattle, you had better use a pine block, as hard wood is not so easy for a beginner to handle. Therefore, for a first attempt, select a piece of sound pine free from blemishes, and plane it down to the dimensions, seventeen inches long, two inches wide, and two inches thick. With a lead-pencil mark off ten divisions one inch apart, running the lines around the four sides of the block (see [Fig. 394]). Then draw two lines lengthwise on each side of the block, as shown at AB and CD, making them one-half inch apart and three-quarters of an inch from each edge. With a chisel, cut out the four corners of the block down to the tenth line, as represented by the shading in [Fig. 394].