Notices respecting New Books. | 137 
most secure: for explosions sometimes occur from the earth to 
the clouds ; and many instances are on record in which the lowest 
story of a building has been the only part which has sustained 
injury; hence it is absurd to take refuge in a cellar, or cave, &c. 
Chimneys are excellent, conductors, from the soot ‘or charcoal 
with which they are lined: consequently it is essential to avoid 
any approach to the fire-place : and the same caution is neces- 
sary with respect to gilt furniture, bell wires, and extensive sur- 
_ faces cf metal of every description. In a carriage, the precaution 
of keeping at some distance from its back and sides is also. ad- 
¢ visable. The several varieties of the thunder-storm are shown 
to be closely imitated by a proper use of the electrical apparatus; 
r and the source of the vast accumulations of electricity by whieh 
. these phenomena are produced, is traced to the circulation of wa- 
Px 
ter in the atmosphere: hence thunder occurs most frequently in 
summer, and storms are most tremendous in all situations where 
» the sun’s influence operates to the greatest extent. The exact 
nature of these natural processes cf excitation is at present far 
from being clearly understood ; but the- analogy between them 
and many of our artificial methods is clearly described in the 
following observation of our author :-—* The diferent electrical 
state of different parts of the atmosphere, obtains principally im 
the masses of vapour or clouds that float in it; and the origin 
of this electricity, as well as the cause of its various changes, is 
probably to be traced to the mutability of these masses ; for it 
has been seen, that change of form, heating and cooling, fric- 
tion, and the contact of dissimilar bodies, are the ar tificial sources 
of electrical excitation, and the clouds experience in succession 
the operation of all these causes.” The opinions of Volta, 
» Saussure, De Luc, &c. are given with great impartiality, and 
as fully as is consistent with the nature of the work. 
. The phenomena of the northern lights, and other luminous ap- 
pearances of the atmosphere, are also treated at some length ;: 
and this section deserves notice for the clearness with which the 
various facts are stated. The author shows a marked distinction 
between the larger and smaller meteors. “He considers the lat- 
teras very analogous to the appearances of electricity ; but the 
Jarger meteors he regards as incapable of explanation in the pre- 
sent state of our knowledge. 
In describing the means of observing atmospherical electricity, 
an account is given of a very remarkable apparatus for that pur- 
pose, which has been recently constructed by our corr espondent 
Mr. Crosse of Broomfield. It is described as ¢ consisting of 
copper wire, one-sixteenth of an inch thick, stretched and insu- 
lated between stout upright masts of from 100 to 110 feet in 
ight, The most unwearied exertion has been employed to 
give 
; 
L: 
\ 
