Mr. Genet’s Vindication. 89 
five quantities, formed by a complication of ares and circles, 
and who proves, by calculations which he is willing to lay be- 
fore the most scientific men, that the quantity of a circle, 
whose diameter is 1, and which had hitherto been considered 
to contain 78,5898, &c. contains more than 79, &c. These 
facts are sufficient to prove that the authority of Metius is not 
as conclusive as the editors of the Boston Journal make it; 
and that if so many errors, notwithstanding the extensive nse 
of the circle, have been committed by the most skilful men, 
an approximate proportion of 1 to 3 was not absolutely im- 
proper, in the rough description of a wheel, and did not de- 
serve the unmerited sarcasm of my having changed the rules 
of Metius. Ce n’est point mot Messieurs qui ai change tout 
_ cela, c'est, entre autres, un scavant de l’ Athenes @ Amerique. 
Next to this side blow, given to the wheel of my elevator, 
with the heavy volume of Metius, the Boston reviewers are 
not better pleased with the use [ make of the same wheel to 
recal down the balloon after its ascension, without consider- 
ing that a loss of gas, for which a valve or stop cock has been 
provided, is to aid the descent of the balloon after it has pers 
formed its ascension in the cupola, or tower, and that a new 
engine, or by a falling weight, as one Robert Fulton has 
proposed it a great while ago °” to whicl question I answer, 
that it would require the power of seven horses and one half 
power, to draw up a boat of 60 tons on a rise of 44 inches 
per chain, and twenty horses on a rise of one perpendicular 
foot to 15 horizontal, and that the primary cost and keeping of 
such a number of horses, or of a standing steam engine equal 
in power, would much exceed the smalj] expense attending the 
construction and keeping of an zrostat, as it may be seen by 
the calculations on that subject in my memorial, and as I 
could more particularly show if that information were requir- 
ed for actual experiment. With respect to the machine very 
concisely described by the reviewers as the falling weights of 
- Fulton, itis well known that his views on that subject, though 
applicable, and previously to Fulton effectively applied, to 
extraction of coal and other minerals in England, Scot- 
Jand; Germany, and other countries, have met with dif- 
ficulties and objections as to their applicability to canals 
