AMERICAN INSTITUTE. 



*193 



Dome Spring Steam Gauge. 

 Boston Steam Gauge Co., E. G. Allen, agent, Boston, Mass. A> 

 is the case. B, the cylinder, that holds the moving power. B, 

 the dome, or closed top spring, consisting of closely wound steel 

 wire, held at the bottom by being screwed into cylinder B, thus 

 leaving the spring free from friction. C, is a tube or linicg of 

 vulcanized rubber inside of the spring D. F, connecting wire 

 from spring to rack, g, the rack, h, the strap which holds the 

 rack and pinion. G, the packing screw and coupling. 



[Ji silver medal awarded. 

 [Am. Inst.] 13 



