Hill Locomotive Tests.
[Jour. Frank. lust.~ perature, while the other action can only occur by compression, with al~stra(;tion 1)y surrounding b,)dies of all he'~t due to such reduction of vohllne.
Hence, in all heat engines, so tar as we now know, there must be a rejection of unutilized (~lergy ti.om the working cylinder, the proportion of initial heat to that thus lost being determined by the working" temperatures adopted, and the absolute amount of waste per pound oF working substance being determined by its physical properties and the distance of the absolute zero. below minimum working level or" temperature.
TESTS OF A BALDWIN LOCOMOTIVE.
By JOH3" W. HrLL, ]~I. E., Member Americ'm Society of Civil Engineel.~.
(Continue,1 fi'om vol. lvii, page 272.) In tile ibllowing table ttle diagrams have been worked in l)ai~ tbr each engine (right aud lei~), and arc given with the boiler pre~ure, revolutions, and the track, for each s~.ries of cards. The series are numbered from 1 to 40, Cincinnati to Hamihon ; ii'om 1 to 20, Hamilton t~) Twin. Creek, and fi'om 1 to 21, Twin Creek to Dayton.
In columu 1 is given the order in which the diagrams were taken; column 2 giv~ the pre.ssure in the boiler taken simultaneously with the diagrams ; column 3 contains the revolutions corresponding with each seri~ of diagrams. As already explained, th'e engine counter failed after running a short dis 'tancc, and the revolutions are deduced from the observed time ii~ running between fixed stations. This method, although not as desirable as an aetsml record of the revolutions by speed counter, was the only means Iff which the speed could be noted after the counter broke and cannot be in error sutficientlv to aflt~ct the final r~sults. The dis-tanc~s between stations (of which there were nineU-six in a run of fiftynine miles) were carefully measured, aider the tests~ and the time in running t~om one station to the next was noted to seconds, and by the ob~rver entered in his note book.
Columns 4 and 12 contain the initial pressures averaged for each pail-(,f ~rds. This is the pressure at eonunencement of stroke and, '~s will be observed, is approximately the same tbr both engines during each 0f the thrt~ runs. C,)]umns 5 and 13 contain the eut-off.~ in fractions oi" May, 1879.] Hill--Locomotive l'e.~ts.