071 some Modifications of Recording Apparatus. 349 



parts — 6 in., 4^ in., and 2J in. in diameter respectively. 

 This pulley is attached to a collar and pinching-screvv, by 

 which it can be fixed at any point on the spindle. The 

 spindle is cupped at both ends, and turns between two 

 bearing-points. The lower one is fixed to the horizontal base 

 of a strong wooden stand, and the upper is borne by a strong 

 brass arm, which projects from the upright part of the stand. 



The stand is made of two pieces of thoroughly seasoned 

 mahogany, If in. thick. The upright part measures 12 J in. 

 by 8J in., and the base is of the same breadth, and 7 in. from 

 before backwards. The two are fastened together by strong- 

 screws, and are rendered still more rigid by means of two 

 iron knees. 



As already stated, the base carries a bearing-point for the 

 lower end of the spindle. This is fixed to a brass disc, which 

 is screwed down to the wood, and is set 3 in. from the front 

 and the same distance from the right side of the base. This 

 brings the side of the drum to be flush with these sides of 

 the base. The upper bearing is carried by a heavy brass 

 knee, 1\ in. broad and IJ in. thick, firmly screwed by its 

 perpendicular part to the upright. The horizontal arm 

 carries the pointed bearing- screw. This screw is similar to 

 that in the frame of the clock already described, and is fixed 

 in the same way. 



The distance between the two points is 16 J in. This 

 length of spindle enables the drum to be moved considerably 

 more than twice its height in a vertical direction. The 

 pulley on the spindle is adjusted so as to be on a level with 

 the pulley on the clockwork, when the latter is on the 

 bracket at the end of the table. A soft cotton cord, forming 

 an endless band, passes round one or other groove on the 

 pulley of the clock to one of the pulleys on the spindle of 

 the drum ; and it will be seen that a considerable variety of 

 speeds can be obtained by changing the cord from one groove 

 to the other. There being three sizes of pulleys on the 

 spindle and two on the drum, we have six different speeds 

 with each speed of the clock, thus giving twelve different 

 speeds by this means. If we include the two speeds avail- 

 able when the drum is driven directly by clockwork, we 



