1866.] Astronomy. 389 
eclipse of the sun, October 8, 1866, is partly visible at the 
Observatory, and 
Begins . . . . 4h. 19m. 39s. 
tester pins : LS Mean time at Greenwich. 
At Crumpsall the Sun will set at 5h. 27m. Magnitude of the eclipse 
(Sun’s diameter = 1). 0-480. 
x . 4 2 act, 43° . : ’ 
aan ee ead ne 3 : \ Towards the west for direct image. 
At the same meeting of this Society, Mr. Brothers, F.R.A.S., 
stated that, while observing the Moon with his five-inch achromatic 
telescope, at about eight o’clock on the evening of March 25, he 
observed a small dark body cross the disc diagonally, from left to right, 
a little below the spot Copernicus. ‘The motion was very rapid, and 
similar to the passage of a luminous meteor across the field of view. 
He conceived it might be a meteoric body passing through space at 
a distance considerably beyond the limits of the earth’s atmosphere. 
Mr. Daubrée has given to the Academy of Sciences a continua- 
tion of his ‘‘ Synthetical Researches relative to Meteorites.”’ In this 
part he shows that the siliceous constituents of meteorites are, for 
the most part, basic silicates, differing from the silicates constituting 
the superficial crust of the earth, but closely resembling the eruptive 
rocks. He supposes the masses to have been formed originally at avery 
high temperature, but for several reasons believes that they have crys- 
tallized at a lower temperature than in his own experiments to re- 
produce them. He supposes also that the fragments which reach our 
earth have been detached from much larger masses, probably at a far 
distant period of time. Butalthough long circulating in space, it is only 
when they reach our atmosphere that they suddenly become incan- 
descent, by which their exterior becomes vitrified, while the interior 
remains unchanged. The interior, therefore, represents the state of 
the mass as it circulated in space. It is clear, however, that oxygen 
has played an important part in the formation of meteoric stones, 
and the author also thinks in the formation of all planetary bodies. 
This part of M. Daubrée’s paper is very long, and we have only 
indicated the principal pomt. ‘The memoir is a valuable contribu- 
tion to chemical geology. 
PROCEEDINGS OF THE RoyAt ASTRONOMICAL SOCIETY. 
By desire of the Rev. R. Main, Director of the Radcliffe Obser- 
vatory, Oxford, Prof. F. Kaiser, Director of the Observatory at 
Leyden, has presented to the Royal Astronomical Society a brief 
account of his investigations of Airy’s double-image micrometer. 
The Astronomer Royal himself has given a complete theory and 
description of this micrometer. From that theory and description 
