W. A. Norton on Ericsson's Caloric Engine. 405 
ent off to be at 12 (=-652) of the stroke, then the mean effect- 
We pressure, in each cylinder, would be 6:4 lbs.+165 Ibs. ; and 
the horse-power of both engines, calculated by the rule given 
on page 403, would be 311. If we take the cut off oe. Re 
it is stated to be in some accounts, then the mean effective press- 
wein the working cylinder we find to be 6-04 Ibs. +15 Ibs., 
While that in the supply cylinder remains at 64+15. With 
these data the result obtained for the horse-power is 259. 
For a mean effective pressure, in each cylinder, equal to 6 lbs. 
the result is 292; and for 64 Ibs., it is 316. 
The power developed by the engines on the trial trip, was un- 
ubtedly less than the determination above obtained (311), for 
reasons mentioned on page 403; we may safely conclude 
that & could not have exceeded 300 horses-power. It was probably 
less, This is but one-half of the full power of the engines, ac- — 
cording to Captain Ericsson’s estimate. his estimate supposes 
4 Working pressure of 12 lbs. to be employed, whereas, by reason 
of leakage, &c., but 8 lbs. could be obtained. In fact, making 
calculation on the supposition of a working pressure of 12 
°s., and taking the cut off at 3 stroke, neglecting also the clear- 
ance, which is not known, I find the horse-power of the two en- 
sites to be 640. The allowance for clearance, and other causes 
t teduction which have been indicated (see p. 403), may well 
“duce this determination to 600. : eee 
| _ The power, but for practical difficulties, may be indefinitely 
| * ive by enlarging both cylinders, keeping their relative size 
_ltis stated that Captain Ericsson has fixed upon 12 Ibs. as the 
highest limit likely to be practically reached in the working of 
‘lotic engines. "This must be regarded as an indication either 
at itis not expected the leakage will be entirely stopped, or 
that it is Supposed that it will not be regarded as safe and eco- 
homical, to work at the high temperature of 500°, and upwards, 
"<Ssary to double the expansive force of the air. ’ | 
Consumption of Fuel, on trial trip, 6 tons of anthracite coal 
et day, or 560 Ibs, per hour. This amounts to 1°07 ; 
'Se-bower per hour. If the full power of the engines (6U0) 
Were to be developed, the expenditure would be 0-93 Ibs. per 
Power per hour. On the other hand, if we allow that the 
a of pressure in the receiver over that in the working cylin- 
1) ON the trial trip, was se of a pound per square inch, and the 
pressure in the supply cylinder over that in the receiver 
the Same, we find that, with a cut off at 3, the horse-power de- 
Veloped could not have been more than 248. The expenditure 
f fuel, answering to this determination, would be 2-26 Ibs. per 
_ "ower per hour, 
