423 
18S5.J Analyses of Books. 
answering to our December, is the most inclement month, 
having a minimum temperature of 19 0 F. The mean annual is 
53 ° 34 ' F., or better by about 4 0 than that of the South of 
England. The maximum heat registered at Omeo is io5°F., so 
that the absolute range is 86°. By some clerical or typographical 
error it is made 128°. Here, as in the United States and in 
England, it has been observed that exotic plants often flourish 
on the ridges whilst perishing in the valleys, to which the cold 
air flows down. 
At Omeo it would seem that spontaneous evaporation is in 
excess of rainfall. 
The author — as well as Mr. Griffiths, and subsequently Dr. 
Von Lendenfeld — has detected evidence of a Glacial epoch in 
the colony of Victoria, probably in the Post-Miocene. On this 
subjedt the author announces a paper, which we hope to have 
the pleasure of noticing. 
On the Mechanical Characters of Lightning Strokes. By Col. 
the Hon. Arthur Parnell, late. Royal Engineers. 
In this pamphlet, the reprint of a memoir read before the Royal 
Meteorological Society, and inserted in their “ Quarterly Journal ” 
for January, 1855, the author argues from fadts that physical 
force, as manifested in mechanical work, is a principal charac- 
teristic of lightning strokes. Indeed, as far as his own observa- 
tions and the evidence which he has colledted go, mechanical 
work is their main effedt. It would appear that the more power- 
ful the stroke, the less heat effedt is produced. The cases 
tabulated show 1221 instances of mechanical work as against 
only 485 of heat work. Col. Parnell conceives of lightning as 
“ a luminous manifestion of the explosion caused by two equal 
forces springing towards each other simultaneously from the 
earth and the under surface of the inducing cloud, and coalescing 
or dying out nearly midway between the two plates of the elec- 
trical condenser formed by the earth and the cloud.” He also 
holds, upon the strength of a number of observations, that * of 
these two forces it is the “earth-sprung or upward force alone 
which injures persons, buildings, or other objedts on the Earth’s 
surface, and which constitutes tangibly what is rightly known as 
a lightning-stroke.” 
It is certainly, on the commonly-received view of lightning- 
strokes as coming from above, remarkable that history presents so 
few cases where the injury must necessarily have been inflidted, 
and so many where the force must almost beyond doubt have acted 
from beneath. It is much to be desired that, in future cases of 
