( 437 ) 
are not equal to those of the corresponding year, as if 
something of a repressing nature were at work. Some of 
these differences are to be explained by the unequal move- 
ments of the moon, others perhaps by local causes. But 
as an unusual depression is, as a rule, followed by an 
unusual elevation, and vice versä, I am inclined to attri- 
bute these variations to inequalities in the moon’s daily 
motion. 
Another point worthy of consideration is that if the 
movements of the barometer slacken at one period of the 
moon’s course, they endeavour to make up the loss by 
increased activity, in order, as far as possible, to keep 
the months weather within its proper range — the 
month being, not a period from new moon to new moon, 
but from apogee to apogee, or rather from a certain lime 
after apogee to the same time after the next apogee. 
Indeed I find that ordinary monthly results are sometimes 
misleading. If they could be given in what f shail call 
apogee months, the matter would be much clearer, espe- 
cially as regards monthly means. 
As for thethermometric curves, an examination will show 
that they follow barometric curves in a very remarkable 
Way. 
I may say that the records for sixty-two years ago are 
those of the Royal Society, which are necessarily imper- 
fect, compared with those of the present day, being the 
mean of two readings, one at nine a. m., the other at 
three p. m. Yet with these imperfect records the similarity 
is so strong, that one cannot doubt for a moment that the 
cause which was at work sixty-two years ago is that 
which is at work now. 
In regard to the monthly means given in the tempera- 
5"° SÉRIE, TOME XINI. 
