57 
features of the floor of Plato had been made, and thirty-six of the 
small craterlets, and thirty light streaks discovered. A large number 
of interesting phenomena had been noted and a very complete know- 
ledge of its varying states registered. The British Association voted 
asum of money for computers’ assistance to forward the work under 
Mr. Birt’s direction, and among the results of his most elaborate dis- 
cussion of the observations might be mentioned that intermittent 
visibility of the minute craterlets was proved ; and, further, that this 
variation was not in accordance with the angles of illumination and 
vision. Another result was, that the varying tints of the floor were 
as the solar altitude at the spot. 
It might be briefly stated that both the idea of a present Lunar 
_ activity in the smaller features, and the other idea of a possible lunar 
atmosphere seemed supported by the investigation so far as the floor of 
Plato is concerned. Whether what was true of one locality was true 
of the whole Lunar’surface was a question requiring the aid of other 
observers. But, perhaps, enough had been adduced to prove the 
position assumed at the commencement of the lecture, that, whatever 
we did know of our satellite, there was too much left still unexplained 
to admit of our replying in a positive manner to the question ‘* What 
is the Moon ?” 
A large plan of the floor of Plato, on the scale of four miles to 
the inch, from Mr Pratt’s observations, was shown ; also, some stereo- 
: scopic photographs of the moon, taken by Dr. De La Rue ; and Mr. G. 
Nash exhibited some Lunar photographs by means of his oxy-hydrogen 
lantern. 
APRIL, 
MICROSCOPICAL MEETING, — DR. HALLIFAX ON 
CERTAIN FACTS IN THE ANATOMY OF THE 
CUTTLE FISH. 
Those present at the last meeting would (said Dr. H.) recollect that 
_ adifficulty arising respecting a subject, it was suggested that he should 
introduce the cuttle-fish, as there were several points in its anatomy 
