326 Remarks on AErostation. 
then, why is not the analogy perfect between a ship thus si- 
tuated and a balloon? The analogy fails in this point ; the 
balloon floats entirely in one medium, while the ship is divid- 
ed between two—and what difference does this occasion in 
the capacity to generate and apply power? The difference 
is this ; the power, in the case of the ship, is generated i ina 
rare and applied in a ie medium. There is little in so 
ium as air to impede the movement of limbs and 
‘gaachines, " while the inthe: strike with great force upon the 
dense medium, water, and thus produce a full effect. In the 
case of a balloon, the ace in which the movements gene- 
human muscles will soon be exhaus 
The navigation of submarine boats, is meectly -idvasbl 
{respiration aside) to that of balloons. In the submarine 
boats, if the hidden navigator can be supplied with air and 
can keep out the water, he can indeed move at pleasure by 
the impulse of oars or paddles, upon the same medium in 
which his machine floats, but he cannot moye rapidly, be- 
cause the medium is too dense for the free motion of his wings 
or oars, and they cannot be applied on a great scale, because 
there is not a equate power within, to overcome _ the resist- 
ance without.* Such machinest move therefore tardily, un- 
less impelled by the currents of the water, in which case they 
are acted upon precisely as the balloons are in the atmos- 
phere. 
Mr. Genet proposes to call in the aid of apr strength, 
= to work his balloons by horse power, applied to ma- 
e his drawings and descriptions Vol. XI. p. 346 
of this Journal.) 
This is a novel attempt—nothing beyond the power of hu- 
man muscles having been, as yet, applied for this purpose ; 
_and experiment alone can decide whether any very conside- 
table e eflect can be aoe even by horses, in modifyi ing 
the di: n of a balloo 
ig his case to te from that of the fishes 
very interesting account, by Charles Griswold, Esq. in the se- 
: of this Journal, p. 94, of the of Sergeant 
= ee, i New-York during the ie sibiethinary war. 
