Natural Philosophy. — -Meteorology. SS5 
not the means of determining the exact position of these spots. 
On the evening of the 29th November, the large spot was fully 
as bright as before, two others were nearly invisible, and the 
small brilliant spot had disappeared. — See Phil. Trans, 1822, 
Part I. p. 237, 238. 
6. Comet ^1822. — M. Gambart first discovered this comet at 
Marseilles, on the 12th May 1822. - It was observed at Paris 
on the 18th May, and from these observations M. Nicollet has 
computed the following elements of its orbit. 
Passage of the perihelion 6th May 1822, at - 5' 11" a. m. 
Perihelion distance, - - - - - 0.504220 
Inclination of its orbit, , - - - 53“^ 34' 3" 
Longitude of ascending node, - - - 177 30 50 
Longitude of perihelion on orbit, - - - 192 48 45 
Heliocentric motion retrograde. 
This comet is very small, and has no appearance of a tail. It 
has no resemblance in its elements to the comet that is expect- 
ed, nor to any other. 
7. Accowit of Mieussec’s Chronograph for noting small in- 
tervals of Time. — This instrument has the form and size of a 
large pocket chronometer. The dial-plate is moveable on an 
axis passing through its centre. This dial makes a revolution 
in a minute, and each of its divisions corresponds to a second 
of time. When the observer wishes to mark the precise instant 
when any phenomenon takes place, he presses a button, and a 
small pin or metallic point, traversing the summit of a cone fill- 
ed with printers’ ink, and placed opposite the fixed zero of the 
moveable dial, marks on the circumference, divided into seconds^ 
a very fine point, which indicates the second, or fraction of a se- 
cond, which corresponds to the beginning and end of the inter- 
val of time which it fs wished to measure. The instantaneous 
contact of the point has no influence on the motion of the dial, 
and the fineness of the point enables us to estimate the fourth 
part of one of the divisions of the dial-plate. — Bib. Univers. 
June 1822, p. 158. 
METEOROLOGY. 
8. Depression of the Barometer in England^ on the 9>5th 
December 1821. — Mr Luke Howard made the following ob- 
servations on the barometer on the 24th and 25th December 
1821, at Tottenham Green : 
