SCIENTIFIC SUMMARY 
ASTRONOMY. 
A STRONOMY, in England at all events, has lately been taking holiday ; 
so that were it not for the British Association, we should not have much 
progress on this side the Channel to record ; as it is, the Luminous Meteor 
Committee and the Moon Committee have reported, and the latter has asked 
for and got <£120 towards the construction of the map of the moon, to which 
reference has been made on a prior occasion. The report of the former com- 
mittee is chiefly interesting from the fact that the spectroscope has been 
brought to bear on meteors for the first time. The coming November 
meteoric shower is expected to be a very interesting one, and the charts of 
radiant points will be completed in time for use on that occasion. The 
spectroscopes were directed towards meteors on the 10th of August last, 
and seventeen spectra were observed. For this purpose, Mr. Browning had 
constructed three binocular spectroscopes on a plan approved by the com- 
mittee. No difficulty was found in mapping the course of the meteors in 
the spectroscope by the stars, of which a whole constellation— as, for example, 
the seven stars of Ursa major — can be seen in the instrument at a glance. 
The spectra of the meteoric nuclei were seen distinctly in a few cases only. 
They were commonly hidden by the light of the streak when that was 
yellow, and presented highly-coloured and continuous spectra, like the 
spectrum of white-hot solid matter when the streak was greyish white. A 
better night for observing nucleus spectra will be the 12th of December, 
when meteors leaving no trains are for the most part very brilliant. The 
observations of the August meteors appear to indicate the existence of an 
extraordinary amount of sodium vapour. As it is difficult to suppose that 
the vapour of the metal sodium already exists in any sensible quantity at 
the confines of the atmosphere, it must manifestly be brought into the 
atmosphere by the meteors themselves from without, so as to be deposited 
by them in their flight in the luminous trains that mark their course. The 
nucleus is, therefore, probably a fragment of mineral matter, of which sodium 
is one of the chemical, ingredients. 
The report of the Moon Committee states that they have determined to 
use lunar photographs, and to construct a map of 100 inches in diameter. 
The only photograph available for laying down positions was taken by Mr. 
Warren De La Rue, October 4th, 1865. This has been enlarged to 10 inches 
in diameter, and employed for this purpose, as the measures taken from 
it are either without appreciable error, or require but a small correction. 
