1876.] 



an Integrating Machine, 



265 



forward to that value of x. This, he has pointed out, may be effected 

 in practice by having ,a cylinder axised on the axis of the disk, a roll of 

 paper covering this cylinder's surface, and a straight bar situated parallel 

 to this cylinder's axis and resting with enough of pressure on the surface 

 of the primary registering or the indicating cylinder (the one, namely, 



SIDE ELEVATION. 



D, the Disk. 



A, the Axle of the Disk. 

 C, the Cylinder. 



E E, the Axle or the Journals of 

 the Cylinder. . 



B, the Ball. 



PLAN. 



which is actuated by its contact with the ball) to make it have sufficient 

 frictional coherence with that surface, and by having this bar made to 

 carry a pencil or other tracing point which will mark the desired curve on 

 the secondary registering or the recording cylinder. As, from the nature 

 of the apparatus, the axis of the disk and of the secondary registering or 

 the recording cylinder ought to be steeply inclined to the horizontal, and 

 as, therefore, this bar, carrying the pencil, would have the line of its 

 length and of its motion alike steeply inclined with that axis, it seems 

 that, to carry out this idea, it may be advisable to have a thread attached 

 to the bar and extending off in the line of the bar to a pulley, passing 

 over the pulley, and having suspended at its other end a weight which will 

 be just sufficient to counteract the tendency of the rod, in virtue of gravity, 

 to glide down along the line of its own slope, so as to leave it perfectly 

 free to be moved up or down by the frictional coherence between itself 

 and the moving surface of the indicating cylinder worked directly by the 

 ball. 



VOL. XXIY. 



