408 W. A. Norton on Ericsson’s Calorie Engine. 
bilities to be in the proportion of 5 to 7:3, or 5 to 6; that is, to 
be in all probability, in a ratio lying between these two limits. 
If we make a comparison with the Washington and the Hum- 
_boldt, the highest admissible ratio is found to be ~ and the 
57 
lowest —. : 
We conclude therefore that the saving of fuel hitherto effected 
in comparison with the condensing steam engine, in its most eco- 
nomical operation, is not more than 2,* and may be as low as ;. 
At the same time it is to be observed that if the supposed in- 
herent capabilities of the new engine should be realized, the sa- 
ving effected might amount to no less than 70 per cent. 
2. Weight of the Engine. 
Calculation of the Weight of the Engines of the Ericsson.— 
Weight of hull, from 1200 to 1300 tons, as deduced from the 
weight of the hull of the Arctic; displacement, at 17 feet draft, 
2200 tons, as calculated by the builders of the ship; ballast, 200 
tons of pig iron; weight of masts and rigging, coal, &c., 00 
tons, at the outside: hence weight of the engines and paddle 
wheels, = 2200 — 1300 —200—100=600 tons, or 2200-1200 
— 200 — 100=700 tons. ee 
I find that the same rule for the calculation of the displace- 
ment, from the length, breadth, and depth, which gives the dis- 
placement of the Arctic correctly, and a near approximation to 
that of American steamships generally, makes that of the Erics- 
son at 17 feet draft, about 2600 tons, which is 400 tons above 
the estimate made by the builders of the ship; a fact which 4s 
to be attributed, doubtless, to the peculiar model of the ship. 
self pod 
Horse- power. Weight. Rates of weight to borse-powers 
Mississippi, ....| 539 (developed) 494 tons. ool 
issouri,......./ 600 (estimated) 500 0 
eae A Se 367 061 
ichigan, ...... ae 160 0-48 
iagara,.......| 1440 (developed) 150 _ gee 
t 800 ‘“s 600 $20 
Se 300... * 700 2:33 
OS Sam 600 (estimated) 600 1:00 
ee en be made with the Ohio and Georgia, the saving may be 
t This shows the horse-power of the Mississippi developed in its average 
DRESS re ean be no doubt that its full power is 
i . eee oF the weight to the horse-power is as low as 0°82. 
would be deemed @ sufficient allowance. Reducing the total weight hoa ca 
f we take the lowest determination of the horse-power of the Ericsson, on, Viz, 248, 
the ight t > it 2°82. : : 
the norse 
