420 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



shop. I have keen him leave the court room, return to his residence, and 

 immediately go to the Avork shop and resume his labors on a new rotary 

 eng-ine. In 1842, about the time of the introduction of slieet iron stoves, 

 there was considerable attention directed to their advantages, but it was 

 soon f<jund that without great care in the regulation of the drafts, they 

 would burn out, therefore attempts were made to devise some remedy to 

 obviate this evil. It was also found that the joints where the sheet iron 

 was fastened to the cast iron rings at the top and bottom would soon cor- 

 rode by the pyroligneous acid from the wood collecting at the joints. These 

 stoves would heat very quick. If the damper was left open after start- 

 ing the fire the combustion increased so rapidly that the stove became red 

 hot in a short time. Elisha Foot, Esq., a lawyer at Seneca Falls, invented 

 a self-acting damper for these stoves. It consisted of a brass rod, made of 

 sheet metal, and c(»iinected with a lever, which came through the centre of 

 the stove, :md moved a rock shaft, on which was a simple index plate, 

 coming out far enough to hang on a pendulum rod, moving to and fro 

 between two cogs on the damper. Tlie principle applied was the difference 

 between the expansion of a brass rod and an iron rod. When heat had 

 expanded the brass rod the motion was communicated to the pendulum 

 rod, which closed the damper and passed on, until the stove began to cool 

 and the brass to contract, when it would return and open the damper, 

 whicli remained open until the fire became too intense, when it was partly 

 closed- and in this way would alternately open and close the damper till 

 the fire would get just sufficient air to keep the heat at the point desired. 

 About that time it occurred to me that it would be better to regulate tho 

 draft from the outside of the stove, and I accordingly took out a patent 

 for what I called a thermostate, thus dispensing with Foot's rod. 

 It regulated a damper placed on the top of a stove, which was connected 

 with an air pipe placed on the inside and running nearly to the bottom of 

 the stove. By this arrangement there was no danger of coals or fire being 

 blown out upon the floor by the explosive mixture of gases and air, as is 

 sometimes the case where the damper is on the side and near the bottom of 

 the stove. The tlun-mostate consisted of a zinc ring surrounding the dam- 

 per, and resting upon the stove; on the upper side of the ring was a groove, 

 into which was placed a broken ring of steel, one end of which was fas- 

 tened to the zinc and the other left to play freely. As the zinc ring ex- 

 panded the ends of the steel ring moved from each other, and as the zinc 

 contracted they approached each other. The moveable end was connected 

 with a lover which moved the damper. The machine was too delicate and 

 expensive, and never came into public use. This principle, applied as a 

 tiiermometer, might be of some service, as the action of the steel, both for 

 increase and decrease of temperature, is a positive motion, depending con- 

 stantly on the expansion or contraction of zinc, which is the most sensi- 

 tive of the metals to heat. I afterwards found Dr. Ure, of London, had 

 made a h(;at regulator to which he had given nearly the same name, but in 

 his' the elasticity of the metal was made an element, and it could not be 

 reliable. For this reason the spiral thermometer of Breguet, described by 

 Mr. Beaumont, is really of no practical value. Experience has proved this. 

 Mr. Waahburn Bace, also of Seneca Falls, carried out this idea of regulat- 



