80 Mr. Blake’s Reply to Mr. Hendricks. 
11th of February at 5- ‘AO a.m., barometer 29-067, oe 
38-5, wind E. by N., velocity 6:00 miles per hour; the wave 
came from the W. N. W. The barometer dontititied to fall until 
inch); the wind veared about noon by the N. to the W.S. W., 
and increased to a velocity maximum 30:57 miles per hour, which 
continued during the day following i wind W.N. 
Electrical state of the atmosphere.—The atmosphere has af- 
forded indications of electricity, varying in intensity on every day 
or nearly so, during the year, and was generally of a positive or 
vitreous character. "I'wo remarka e electr ical storms occurred 
on the 23d and 3ist of December, ates eh an intensity of 450° 
in terms of Volta’s electrometer, No. 1: sparks of th of an 
inch were constantly passing from the conductor to the discharger 
for several hours each day: it was of a positive character, with 
frequent and quick changes to negative electricity. An increase 
of intensity is always observed during the snow storms of our 
winter ; this increase generally possesses the character of positive 
electricity, although frequent signs of negative electricity have 
been observed here ; this change from positive to negative elec- 
tricity appears to be connected with change in the form of the 
pape of snow. rystals of snow in this climate during the 
very severe silat are ap ote e those described by Scoresby, 
aes figured from 16 to 20 in Kemtz’s Meteorology, also fig. 3; 
and plain hexagonal prisms have likewise been observed. 
St. Martin, Feb. 1, 1853. 
Art. X.—Mr. Blake’s Reply to Mr. Hendrick’s Review of his 
article on the Flow of Elastic Fluids. 
Tue following will be found to be a sufficient answer to the 
criticism of Mr. J. E. Hendricks, in the last number of this Jout- 
nal, upon my article on the flow of elastic fluids published i 
No. 12, vol. v, second series, of this Journal. 
When Mr. Hendricks expresses the pressure by Pé, he should. 
¥ 
so express the quantity discharged by VDS¢. He may then 
eliminate ¢ and obtain an expression identical with my ow®; 
whether the value of ¢ be cypher or unity or any other quantity: 
Hence there is no ground for the oe he would make be- 
tween “ momentary” and other fore 
I avail myself of this opportunity 16 direct attention to an error 
of the engraver of the plate which illustrates the results of my 
experiments on the flow of elastic fluids, at page 191, vol xil, 
second series, of this Journal. The figures at the left of the 
ae (18, 19, 20, &c.) should all be moved upward so as to bring 
umber 30 against the upper line of the plate. : 
Pi ee eee 
