410 W. A. Norton on Ericsson’s Caloric Engine. 
can be set up of superiority on the part of the hot air engine over 
the steam engine, on the ground that the resistance incident to 
the movement of the engine is decidedly less. Also, on observ- 
ing that the horses-power given in Table IL. were used in making 
‘the calculations for the Washington, Fulton and 8S. America, it 
wi seen that the statement just made is still true if we in- 
clude among the several resistances in play in the steam engine, 
the excess of the reaction of the partially condensed steam in 
the cylinder over that of the same in the condenser. e may 
hence conclude that we were justified in making the statement 
that the comparative consumption of fuel by the two engines, 
in producing the same useful effect, is to be ascertained by taking 
the determinations of expenditure given in the last column of 
Table II, rather than the larger values to be found in Table IIL. 
5, Adaptation to the production of high velocities. 
At double the speed of the Ericsson on the trial trip, that is at 
14 to 15 miles per hour, the horse-power would be about eight 
times greater, or about 2400; and the quantity of coal consumed, 
deduced from the present capabilities of the engine, would be 
eight times greater, or 48 tons per day. This supposes the draft 
to remain the same, whereas it will be materially increased by 
the necessary augmentation of the weight of the engines. in 
fact the weight of the engines at the speed supposed would 
be about three times as great as their present weight. At her 
present draft, (viz., 17 feet,) an additional weight of 200 tons 
would sink the hull of the Ericsson one foot. ‘Taking the lowest 
estimate of the weight of the present engines (600 tons), the 
necessary addition of weight would not be less than 1200 tons; 
which would sink the hull nearly 6 feet, or increase the draft to 
about 23 feet, that is, make the draft after the 200 tons ballast 1s 
removed, 22 feet; which is from 1 to 2 feet deeper than the oe 
line. The midship section would thereby be enlarged to 7 0 
square feet, and therefore the power necessary for the production 
of the double velocity augmented in the proportion of 520 to 
720. If this be done, we find the required horse-power to be 
mika would 
produced by the engines and the necessary supply of coal woul 
still be below the load-line. Again, if it should be conjectured 
that the consumption of coal will not be augmented, 
of the caloric engine, in the same proportion as the 
