860 Transactions of the American Institute. 



Regulating the Speed of Steam Engines. 



Mr. C. E. Emery gave a description of the method of regulating 

 the speed of engines by the usual governor. The pressure of steam 

 in the cylinder gives no indication of the power of the engine at the 

 time. Super-heating steam is a loss, because it entails disadvantage 

 at the end of the stroke. Yery late experiments go to show that the 

 ^' indicator," is an entirely useless article. The experiments were so 

 perfect that there was not a cubic foot of water from the condensed 

 steam to be collected in six hours. The power was measured by a 

 blower. The economy of steam engines vary with every pressure. 

 In experiments with the steam engine, much attention should be 

 given to the mechanical arrangements. The trials spoken of went to 

 show that the best way to regulate the power of an engine is by the 

 '' cut off." In his opinion, no engine should be worked with a 

 higher pressure of steam than one hundred pounds. 



Mr. T. D. Stetson said that careful experiments were made at the 

 Crystal Palace in this city, in relation to the speed of steam engines. 

 The trials were commenced on June -ith, 1858, and the report of the 

 committee was published in the London Mechanics^ Journal. . He 

 foimd that all governors were unsteady in their action. 



The chairman said the unsteadiness in power described by Mr. 

 Stetson is common to all self-regulating machines which operate 

 quickl3^ If a steam engine is suddenly relieved of its load, the 

 increased velocity of the piston gives increased centrifugal force to 

 the governor, which instantly moves the cut-off valve, but moves it 

 a little too far ; too little steam being admitted, the balls of the 

 governor descend below their normal height and again open the 

 valve, but open it little too wide ; the surplus steam again increases 

 speed of the governor ; but this oscillation of the revolving balls is 

 less and less until the required velocity of the piston is attained. 

 This oscillating action was beautifully shown by an ingenious inven- 

 tion of the Hon. Elisha Foote, the present commissioner of patents. 

 Many years ago, while still in the practic of the law, he invented a 

 seh'-regulating stove. His apparatus was applied to the ordinary 

 sheet iron stove for burning wood. The difference in the expansion 

 between a rod of brass and one of iron, placed within and near the 

 top of the stove, was communicated by means of levers to a pendu- 

 lum on the outside, the end of which moved between two teeth on 

 the damper, to close it and check the combustion, and then passed on 

 ;nntil the brass rod beo;an to contract, wlien the pendulum moved in 



