extraordinary depression of the barometer. 1 15 
p. 283.) Now, the two latter occurred during the dreadful 
earthquakes in Calabria, of which we have a record in the 
Transactions ; and I believe the barometer was noted to be 
extremely low, about that time, in various distant parts of 
England ; but a comparison of the Society's Register is here 
precluded by a chasm of several years continuance. I have 
no doubt, however, from the general appearance of the means 
in the Lyndon Register, that the barometer there stood com- 
monly some tenths lower than that at Somerset house. With 
respect to my own, I found yesterday, when the quicksilver 
was but little above 30 in., that my portable barometer ex- 
ceeded that at Somerset House, when placed by its side, by 
0.05 in., which was likewise, as nearly as I could judge, the 
difference in excess from my clock barometer. The latter 
therefore agrees very nearly, in this part of the scale at 
least, with the barometer registered in the Transactions. 
I annex to this paper a diagram, traced from the variation 
on the face of my clock, for the two latter months of 1821, 
the scale being three quarters to an inch, (PI. XIII.) placing 
at bottom the amount of rain in each successive five days, 
and the winds, so far as may serve to show their succession. 
It will be seen that this great depression was preceded by 
abrupt changes, fluctuating for 30 days, chiefly between 29.5 
and 30 inches, during a continuance of stormy weather; and 
that the depression itself was 14 or 15 days in progress, from 
the point of 30 inches, to that from which it finally rose in 
three days. 
The rain for these two months is 10.10 inches, a quantity 
without precedent in the same space of time at London: that 
is to say, without one on record. Barker gives, however, 
