been that the genius of
invention and improvement in Europe seems to be absolutely taking a
nap. We have nothing to communicate to you but of the small kind, such
as making the axletree turn with the wheel, which has been proposed
here, adopted by some, and thought to be proved best by experiment,
though theory has nothing to urge in its favor. A hydrostatic waistcoat
is lately announced, which a person puts on either above or below his
clothes in a minute, and fills with air by blowing with the mouth in
twelve seconds. It is not yet shown, however, so I cannot tell you
either the manner or matter of its construction. It may be useful when
the loss of a vessel is foreseen. Herschell's discovery of two
satellites to his planet, you have heard of ere this. He first saw them
in January last. One revolves round its principal in about a week; the
other in about a fortnight. I think your conjecture that the periodical
variation of light in certain fixed stars proceeds from Maculae, is more
probable than that of Maupertius, who supposes those bodies may be
flat, and more probable also than that which supposes the star to have
an orbit of revolution so large as to vary sensibly its degree of
light. The latter is rendered more difficult of belief from the
shortness of the period of variation. I thank you for the shells you
sent me. Their identity with marine shells and their vicinity to the
sea, argue an identity of cause. But still the shells found in the
mountains are very imperfectly accounted for. I have lately become
acquainted with a memoire on a petrification mixed with shells by a
Monsieur de La Sauvagere, giving an exact account of what Voltaire had
erroneously stated in his questions Encyclopediques, article Coquilles,
from whence I had transferred it into my notes. Having been lately at
Tours, I had an opportunity of enquiring into de La Sauvagere's
character, and the facts he states. The result was entirely in his and
their favor. This fact is so curious, so circumstantially detailed, and
yet so little like any known operation of nature, that it throws the
mind under absolute suspense. The memoir is out of print. But my
bookseller is now in search of it, and if he can find it I will put a
copy of it into a box of books I shall send by the September packet,
addressed to Mr. Wythe. In the same box I will put for you the
Bibliotheque Physico-economique, for 1786, 1787, the connoissance des
tems, Fourcroy's Chemistry, whe