ENGINE No. 36. 147 



Engine No. 36 is a cross-compound horizontal engine with 

 steam jacketed cylinders and a jet condenser operated by a 

 direct connected air-pump. The jacket spaces in each cylinder 

 form a thoroughfare through which the steam is supplied to the 

 respective steam chests, the steam first entering the bottom of 

 the jacket at a central point. During the test the drain-pipes 

 provided for carrying off the water of condensation were closed, 

 and all this water passed over into the cylinder. Whatever 

 effect the jackets might otherwise have produced was thus 

 nullified, and the engine may be considered as practically un- 

 jacketed. Steam is supplied from vertical water tube-boilers, 

 and a separator is provided in the main steam pipe. For a 

 short period during the test, water accumulated in the sepa- 

 rator, and its quantity was determined and allowed for. For 

 the balance of the test there was no accumulation, and the 

 steam is presumed to be commercially dry. The valves and 

 pistons of both cylinders were practically tight. The load- 

 consisted of dynamos supplying current for electric lighting. 



Engine No. 36 belonged to the same plant as Nos. 30 and 35. 



The behavior of the steam in its passage through the cylin- 

 ders which the analysis of the indicator diagrams reveals is of 

 unusual interest. The increase in the amount of steam shown 

 at release over cut-off is very large in both cylinders, and the 

 loss of steam which the low-pressure cylinder shows is a marked 

 feature. These actions may be attributed to the effect of the 

 jacket-water in the cylinders combined with the cooling action 

 which always takes place when steam passes from a high to a 

 low-pressure cylinder, where no means is provided for reducing 

 cylinder condensation. In this case the quantities are unaf- 

 fected by steam which leaked, all the valves and pistons being 

 practically tight. 



