80 
and for purposes of correspondence, of telegraphy, and of 
short communications, it seems difficult to find an objection 
to its use. It has been tested, as I said, by Dr. Birch and 
others, and by them found to answer admirably, and if by its 
means the problem be eventually solved by which the vast 
gulf may be bridged which now separates those thinkers who 
do not know each other’s language, a very great gain will have 
been secured. Its inventor, at least, is hopeful enough, and 
has, I believe, in preparation a series of dictionaries in 
several languages ; of these I exhibit three which were dis- 
tributed at the late Oriental Congress, viz., the English, 
French, and German ones. 
“ On the Existence of a Lunar Atmosphere,” by David 
W iNSTANLEY, Esq. 
The non-existence of a lunar atmosphere is spoken of by 
many astronomical writers as confidently as if it were a 
demonstrated fact. It is certain, however, that it is not a 
demonstrated fact, and it is certain also that if a fact at all 
it is undemonstrable. 
The failure of any optical test, however delicate, to detect 
the existence of such an atmosphere still leaves another 
alternative open to us than the inference of atmospheric non- 
existence, namely, the existence of an atmosphere in quantity 
below the minimum discernible by the means employed. 
The non-existence of an atmosphere about the moon com- 
parable in density with that which surrounds the earth may 
indeed be regarded as an established fact ; but the total 
non-existence of such an atmosphere is certainly an un- 
warranted conclusion. 
I shall endeavour to show presently that the refraction 
of a ray of light is not the most delicate test which can be 
employed for the determination of the point in question. 
But even this test has yielded indications which astronomers 
of note have construed into evidence of a lunar atmosphere 
