AMERICAN INSTITUTE. 651 



The object of a cut-off is not only saving of steam, but the en- 

 gine, by relieving the engine from the effect of the severe full 

 stroke of the piston, and giving a well governed stroke to the pis- 

 ton, an effect which is also gained by the action of expansive 

 steam below the piston, which also meeting the power above it, 

 neutralizes the shock or pounding, always otherwise felt and 

 heard. He illustrated Sickel's cut-off, which has recently at- 

 tracted tlie attention of engineers. This valvular arrangement 

 acts by upper and lower valves in a cylinder in which the steam 

 above and the steam below operate against each other, thus sud- 

 denly stopping the admission of steam to the main cylinder, at 

 such point of the stroke as the engineer may select — say at one- 

 eighth, one-fourth, or at half stroke. But Mr. Stetson thought 

 still that the stroke might be regulated in the cylinder, hy steam 

 admitted into it below the piston and acting expansively tofies 

 quoties — as often as desired — as by the slide valve, which may 

 be at will made to lap so as to cut off the steam at one-third of 

 the stroke, leaving what steam is already admitted above, the pis- 

 ton to act expansively, and also, if more expansion is required, 

 then by contracting the steam port, what is termed wire drawn 

 steam — that is a slender opening for it admits steam enough to 

 finish the expansive power above the piston, and thus complete 

 the force of the stroke Avithout shock. In the Cornish engine, 

 the steam is sometimes cut off at one-twelfth of the stroke. 



Mr. Roosevelt — The action of that engine is excellent. Its 

 down stroke slow, uniform to the bottom, and then a much more 

 rapid rise. It does not attempt its power to lift suddenly, but 

 most naturally begins with moderate and then increasing force to 

 overcome resistance. 



Mr. Meigs had examined the noble Cornish engine, in opera- 

 tion, at Belleville, New Jersey, where near the bank of the river, 

 it forces the water up for supply of the Jersey city aqueduct to 

 the summit of the hill near the city, above 100 feet high. John 

 D. Ward of Jersey city, superintended, directed and finished the 

 w^hole of that noble aqueduct, for less money than his original es- 

 timates on which that work was undertaken. 



