ON A CONSTANT INDICATOR FOR STEAM-ENGINES. 



309 



gistering the work done by a team of horses dragging a loaded carriage at 

 any given velocity over any length of road. 



I G N O and E H K in the figure represent two separate pieces, wliich may 

 be made to move upon one another in the directions H K and G I. Two 

 springs shackled together at their extremitie.^, and represented in a subsequent 

 figure, are severally inserted in the apertures G and H, and fixed there by 

 their middle points. 



The separation of the two in the direction G I and H K, supposes there- 

 fore a deflection of these springs. Tlie piece G I is connected with the 

 carriage to be moved by means of the bolt I, and to the piece E H K the 

 horses are attached by means of the shank K. Thus the pressure of traction is 

 transmitted from the horses to the carriage through the system of springs, 

 and by the well-known property of elastic bodies a separation is thus pro- 

 duced in these springs, which (so long as it does not exceed a certain limit) is 

 always directly proportioned to the amount of this pressure. B D represents 

 a flat circular disc, and A L a pulley or sheave, both fixed upon the same 

 vertical axis F C. The sheave A L receives its motion by means of a band 

 from a sheave revolving with the wheel of the carriage, so that the motion of 

 the circumference of A L bears always a constant ratio to the space traversed 

 by the carriage. To tlie piece E H K is attached (by means of a joint or 

 hinge) the box M, containing certain mechanism intended to register the 

 number of revolutions made by a certain wheel. 



This wheel is represented at F; it rests by its edge upon the disc, its plane 

 is at right angles to the line of traction ; and its position on the box is such. 



