On Aérial Navigation. 323 
ration, and therefore the expense would not be considerable.— 
But as no more than 6800 pounds, the unconsumed power of 
this balloon, can be allowed for the weight of the engine, its wa- 
ter and fuel, besides that of an extensive surface for wafting, it 
appears upon estimating the weight of these things*, that 
this balloon, extensive as it is, is, as L-before said, only the long- 
boat of its species, and not quite large enough to take advantage 
of the saving power of the steam-engine at so great a velocity 
as twenty miles per hour: though it will answer the purpose of 
a first experiment at fifteen miles per hour with a proportionate 
saving of fuel. 
Upon larger constructions, however, it will appear that aérial 
navigation will be performed much cheaper in a_ horizontal 
path by the steam-engine, than upon the ascending and de- 
scending plan with the inclined plane. Several years ago I made 
many estimates of the application of first movers to these long 
balloons ; but 1 always found that the enormous size required to 
‘be successfully driven by them, placed the proper scale of ex- 
periments quite out of the reach of any individual, and unfor- 
tunately of such magnitude as to render the public of that day, 
if appealed to, more ‘neredulous than ever upon the subject. My 
own experiments were therefore confined to the inclined plane, 
which offers a good result upon a smaller construction. The 
introduction of the steam-boat, together with “the steady march 
of the human mind” during so many years of unexampled 
scientific discovery, attended by practicable results im the rapid 
‘improvement of almost every art, will now enable me to state 
my ideas upon this subject, without stepping beyond the limits 
of many an inguiring mind. My former paper showed that the 
Montgolfier balloon there described was only the long-boat of 
this class of vessels; yet I felt obliged to pave the way for the 
introduction of so huge an infant obtruded upon the civilized” 
world, by leading the unprepared mind from the contemplation 
of a hundred-gun ship of ninety yards in length, to -a balloon 
of a hundred; and although in the course of this paper I shall 
be obliged to point out objects in reserve upon a larger scale, 
yet as a matter of experiment, I have nothing to add to the bulk 
of the balloon already described, It would be a great advantage 
to that vessel if the greater portion of its long chimney, from 
about twenty feet above the fire, were made of flexible materials 
well coated with the mixture of brick-dust, &e. with which the 
firework-makers protect their materials :—this would allow of 
* Coals for one hour -—— = 360 pounds 
Waterfordo.- - - 3540 
Weight of the wing or waftage 1000 
Leayingonly - - 7~ _1900 for the weight of the engine, 
6800 
Ke proper 
