Astronomical Society. 221 
selves, than that arising from the accident of their being lodged 
in cavities produced in them, by causes wholly unconnected with 
the animals, that appear for a certain time to have taken pos- 
session of them as their habitation. 
Feb. 28. Communication of a curious Appearance lately ob- 
served upon the Moon, by the Rey. Fearon Fallows, in a Letter 
addressed to John Barrow, Esy. 
On the difference in the Appearance of the Teeth and the 
Shape of the Skull in different Species of Seals. By Sir Everard 
Home, Bart. 
March 7. Experiments and Observations on the Dev aopaitae 
of magnetical Properties in Steel and Iron by Percussion. By 
William Scoresby, Jun. Esq. Communicated by the Presntete 
ASTRONOMICAL SOCIETY OF LONDON, 
March 8. A letter was read from M. Gauss, respecting a 
very simple contrivance for a signal, in geodetical operations, 
which may be seen at an immense distance. This contrivance 
is nothing more than the common reflecting speculum of a sex- 
tant; being about two inches long, and an inch and a half broad; 
and mounted in such a manner that it may always reflect the 
solar rays to the given distant point, notwithstanding the motion 
of the sun. The instrument, thus mounted, he calls a heliotrope: 
and the reflected light was so powerful that, at 10 miles distant, 
it was too bright for the telescope of the theodolite, and it was 
requisite to cover a part of the mirror. At 25 miles distant, 
the light appeared like a beautiful star, even when one of the 
stations was enveloped in fog and rain: and at 66 miles distant, 
it was still sufficiently powerful as a signal. In fact, the only 
limit which appears to the use of this beautiful instrument, is 
that which arises from the curvature of the earth. 
This Society has just announced the publication of the first 
volume of their Memorrs: which must be highly interesting to 
every lover of Astronomy. With a true zeal for the science, they 
have resolved to present copies to all their AssociareEs, and to 
most of the scientific Societies and Academies in Europe, Asia, 
and America: whereby their labours will be more genpeally 
known, and duly appreciated. 
L. Intelligence and Miscellaneous Articles, 
EXPLOSION OF A GASOMETER, 
Ox the 15th of March, about fonr o’clock P. M., one of the 
gasometers in Friar-street burst with a dreadful explosion. 
: this 
