1(52 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



the small wheels, G and H, crossing between them and the 

 great wheel, D. On the upper end of the axis of the wheel 

 (T, above the frame, is fixed by a screw the bearer, M. On 

 the axis of the wheel, H, is fixed the bearer, N T Z : and it 

 is easy to see, that when the winch, B, is turned, the wheels 

 and bearers are put into a whirling motion. 



Each bearer has a wire fixed and screwed tight into it by 

 nuts on the outside. And when these nuts are unscrewed, 

 the wires may be drawn out in order to change balls U 

 and V, which slide upon the wires, thus keeping the balls 

 up from touching the wood below them. A strong silk 

 line goes through each ball, and is fixed to it at any length 

 from the centre of the bearer to its end, as occasion requires, 

 by a nut-screw at the top of the ball ; the shank of the 

 screw goes into the centre of the ball, and presses the line 

 against the under side of the hole that it goes through. The 

 line goes from the ball, and under a small pulley fixed in 

 the middle of the bearer ; then up through a socket in the 

 round plate, see S and T, in the middle of each bearer ; then 

 through a slit in the middle of the frame at the top, and 

 P, of each tower, and going over a small pulley on the top, 

 comes down again the same way, and is at last fastened to 

 the upper end of the socket fixed in the middle of the above 

 mentioned round plate. These plates, S and T, slide up 

 and down upon the pillars supporting the tower. The balls 

 and plates being thus connected, each by its particular line, 

 it is plain, that if the balls be drawn outwards, or towards 

 the ends, M and N, of their respective bearers, the round 

 plates, S and T, will be drawn up to the top of their re- 

 spective towers, and P. 



There are several brass weights, some of two ounces, 

 some of three, and some of four, to be occasionally put 

 within the towers, and P, upon the round plates, S and T : 

 each weight having a round hole in the middle of it, for 

 going upon the sockets or axes of the plates, and is slit 

 from the edge to the hole, for allowing it to be slipt over 

 the aforesaid line, which comes from each ball to its respec- 

 tive plate. 



The experiments to be made by this machine are as fol- 

 lows : 



1. The propensity of matter to keep the state it is in. Take 

 away the bearer, M X, and fasten on the round board (Fig. 

 169, opposite page), and the ivory ball, a, to' which the line 



