THE following is an explanation of a graphic method for calculating the theoretical efficiency of gas-engines. The specific heats and other data are taken from a Paper by Mr. Leonard Bairstow.1 From general thermo-dynamic relations d H = k , d t + p d @ , where H denotes heat added (in foot-lbs.). kv ,, specific heat a t constant volume (in foot-lbs.). t ,, absolute temperature in degrees Centigrade. P ,, absolute pressure in pounds per square foot. V ,, volume in cubic feet. I n adiabatic expansion or compression d H = 0, and the equation becomes k , d t =-p d~, but for a gas p V = R t, therefore by substitution for y and integrating R. If v1 and 2r2 be any particular values of W, and t , and t, the corrcsponding temperatures, log c may be eliminated, and l R t!2 t l log 'U1log u2 =-p, d (log t)d (log t). . (1) K. to to Where to is any convenient value of t which may be chosen as the starting point.
CORRESPONDENCE ON PORT IMPROVEMENTS [Xinutes ofMr. Farrow. loading of ordinary vessels, having no special provisions for t,he selftrimming of coal were given :-S.S. " Saros" loaded with 3,645 tons in 1 2 hrs. 36 min. by 3 cranes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.