Analyses of Books. 
157 
coal which hare been long burning, but the results have been merely baked clay and 
schists, and it has produced no results similar to lava.” 
“ If the idea of Lemery were correct, that the action of sulphur on iron may be 
a cause of volcanic fires, sulphate of iron ought to be the great product of the 
volcano, which is known not to be the case ; and the heat produced, by the 
action of sulphur on the common metals, is quite inadequate to account for the 
appearances. When it is considered that volcanic fires occur and intermit with all 
the phenomena that indicate intense chemical action, it seems not unreasonable to 
refer them to chemical causes. But, for phenomena upon such a scale, an immense 
mass of matter must be in activity, and the products of the volcano ought to give an 
idea of the nature of the substances primarily active. Now what are these products ? 
mixtures of the earths in an oxydated and fused state, and intensely ignited ; water 
and saline substances such as might be furnished by the sea ; and air altered in such 
a manner as might be expected from the formation of fixed oxydated matter : but it 
may be said, if the oxydation of the metals of the earths be the causes of the 
phenomena, some of these substances ought occasionally to be found in the lava, or 
the combustion ought to be increased at the moment the materials passed into the 
atmosphere. But the reply to this objection is, that it is evident that the changes 
which occasion volcanic fires take place in immense subterranean cavities; and that 
the access of air to the acting substances occurs long before they reach the exterior 
surface.” 
“ The same circumstances, which would give alloys of the metals of the earths 
thepower of producing volcanic phenomena, namely, their extreme facility of oxyda- 
tion, must likewise prevent them from ever being found in a pure combustible state 
in the products of volcanic eruptions ; for before they reach the external surface they 
must not only be exposed to the air in the subterranean cavities, but be propelled by 
steam, which must possess, under the circumstances, at least the same facility of oxy- 
dating them as air. Assuming the hypothesis of the existence of such alloys of 
the metals of the earths as may burn into lava in the interior, the whole 
phenomena may be easily explained from the action of the water of the sea and air 
on those metals ; nor is there any fact, or any of the circumstances which I have 
mentioned in the preceding part of this paper, which cannot be easily explained ac- 
cording to that hypothesis." 
The hypothesis of a central fire is alluded to in the conclusion, as also sufficient 
to account for the phenomena ; and Sir Humphry Davy thinks the increasing tempe- 
rature of the earth, as we descend, affords some probability of the existence of such 
a central heat. 
A7. Abstract of a Meteorological Journal kept at Benares, during the years 1824, 
•825, and 1826. By James 1‘rinsep, Esq. Assay Master of the Mint at Benares, 
communicated by Peter Mark Rnget, M . Z>. Sec. R. S. 
A great deal of useless trash is annually, quarterly, monthly, and occasionally, in- 
flicted on the public under the title of Meteorological Registers. Every one wishes 
to be a meteorologist, every one observes and records ; but no one wdl submit to the 
labour of reducing his observations, and extracting from them any useful results. 
The present paper is an example of what a meteorological register ought to be. In 
a single page are comprised the mean results of observations made twice a day for a 
whole year. Three pages then contain the three years' results. 
From these we learn that the annual mean of the several particulars is as follows. 
Year. 
Barometer. 
Ther- 
mometer. 
Mean comp, 
tension. 
Hair hygro- 
meter. 
Evapora- 
tion. 
Rain. 
1824 
_ 1825 
Inches. 
29,593 
29,620 
77°, o 
78°, 1 
87 
60,4 
67 
Inches. 
38,3 
46,9 
’Die observations, it is to be regretted, were not made at the same hours ; they 
varied from 9 A. M. to 101, and from 5 P. M. to C|. The mean temperature of the 
atmosphere for those hours was in 1824, 2", 5. above the mean of the extremes ; in 
1825 only T.84. The greatest monthly excess is 5' ,2. By Dr. Brewster’s paper in 
the Transactions of the Royal Society of Edinburgh, in which he gives the registered 
temperatures for every liour during two years, as observed m Leith Fort, it appears 
that the mean of 1(1 A. M, and 6 P. M, for two years is 1°,4, above the mean tem- 
