92 Animadversions on Mr. Genet's Memorial, fyc. 



loon after it has ascended, is to be drawn down again ; I beg 

 pardon, " recalled down ;" and, I will here ask another ques- 

 tion ; how much less power will recall it down, than that 

 which it exerted in its ascent ? and why not use this power to 

 draw up another boat, without troubling the balloon ? 



In calculating the power requisite to draw a boat of sixty 

 tons, up a plane with a rise of one foot in fifteen ; Mr. Genet 

 estimates it at 3200 lbs. Now I had understood, though, to 

 be sure it was according to the exploded philosophy, that in 

 order to sustain a weight upon an inclined plane, the power 

 which sustains it, must bear the same proportion to the weight, 

 which the perpendicular height of the plane bears to its 

 length ; and that consequently in the contemplated plane, it 

 it must be equal to one fifteenth of the load of sixty tons, that 

 is 8,000 lbs. instead of 3,200. ; a trifling difference this, and 

 easily obviated by enlarging the house, the balloon and the 

 laboratory, to considerably more than double their capacity ; 

 but even then, the whole will be at rest, as we have yet to 

 overcome friction, and to give motion ; to effect which, an- 

 other addition must be made to the power, which shall in- 

 crease it to about four times the estimate. 



The foregoing is, comparatively, a slight deviation from 

 correctness, as will appear upon examining the operation of 

 the wheel thirty feet in diameter, and, in the round numbers 

 of Mr. Genet, ninety feet in circumference. The rope or 

 chain, which is to draw up the boat, is to pass over a drum 

 or drums, of twenty feet in diameter, or sixty in circumfer- 

 ence ; the large wheel is to drive a pinion on the drum shaft, 

 and give to them fifteen revolutions for one of the large 

 wheel so that the periphery of the drums will travel through 

 900 feet, whilst that of the large wheel travels 90, and of 

 course, if the balloon be allowed to ascend 90 feet, it must 

 draw the boat 900 feet. It is rather an inverted procedure in 

 mechanics, to drive a pinion, by a wheel of fifteen times its 

 size ; but the object to be gained is very great indeed ; no less 

 than to cause a power of 3236 lbs. moving through a space of 

 90 feet, to raise 60 tons to the perpendicular height of sixty 

 feet. According to the exploded philosophy, 80,000 lbs. or 

 twenty-five times the amount assigned in the Memorial, would 

 just balance the sixty tons. How mighty are the Upward 

 forces. 



For the mode of filling the aerostats, instantly, with the coal 

 gas, Dr. Pascalis refers to the Memorial : anxious to learn how 



