. 
1825.] 
tained by the solution of iron in sulphuric 
acid, being made to pass into pure alcohol, 
nearly loses its smell. Water, added to the 
alcohol, renders it milky, and, after some 
hours, a‘volatile oil separates, which is the 
cause of. the, smell... But an amalgam of 
potassium being mixed with pure water, 
the gas is obtained without smell; if an 
acid, or sal-ammoniac, be added to the 
water to accelerate the development of the 
gas, it will partake of the smell, during the 
solution of zine in weak sulphuric acid.— 
Ann. de.Chim. 
_ Thermometrical.—M. Avago, in an ar- 
ticle in the ‘‘ Annales de Physiques,”’ dis- 
cusses the question of the temperature of 
the globe at its surface, and arrives at the 
conclusion, that in Europe generally, and 
particularly in France, the winters have, for 
centuries, been ascold as now. This opi- 
nion is grounded on the fact of the 
frequent notices of the freezing of rivers 
and seas, at very remote dates. Having 
given a table of the extremes observed in 
the temperature of Paris, M. A. gives the 
observations of Captains Parry and Frank- 
lin, and the dates of the natural congela- 
tion of Mercury, together with tables of 
the maximum temperatures on land and 
on the open sea. His contemporary, 
M. le Baron Fourier, has published a 
memoir, which induces the Editors of the 
*€ Bulletin Universel”’ to congratulate them- 
selves at being able to support, by learned 
mathematical theories, which are only the 
expression of observed facts, the opinion 
they have long maintained of the depres- 
sion of the temperature of the earth’s sur- 
face—a change to which has been attributed 
the modifications which life has undergone, 
proclaiming an inevitable return to the prin- 
cipal geological principles of Count Buffon. 
According to the learned Baron, the heat 
of the earth arises from three sources : — 
Ist. The solar rays; the inequality of the 
distribution of which occasions the diversity 
of climates:—2nd. The earth partakes of 
the common temperature of the planetary 
spaces, being exposed to the irradiation of 
the stars, which surround the solar system : 
—3d. ‘It has preserved, in the interior of 
its mass, a part of the heat it. contained, 
when the planets were originally formed. 
‘These three causes, and theresulting pheno- 
mena, are examined separately: and M.F. 
says, the opinion, that internal fire has caused 
the continual recurrence of great. pheno- 
mena, his been constantly received. The 
form of the terrestrial spheroid, the regular 
disposition of the strata manifested by pen- 
diulum observations, the density and depth 
of these, and many other considerations 
coneur to prove, that intense heat has pene- 
trated the globe throughout. ‘This heat has 
been dissipated by irradiation into surround- 
ing space, the temperature of which is below 
that ‘of fréezing water. The law. of refri- 
geration, mathematically expressed, shows 
that the original heat, contdined ina sphe- 
j 
Spirit of Philosophical Discovery. 
437 
rical mass, of dimensions equal to the 
earth's, diminishes much more rapidly at 
the surface than at the parts situated at a 
great depth below it. These long preserve 
a large portion of heat; and, calculation 
shows, that the results have not been. mis= 
apprehended: hence, adds. our. author, 
having shewn that the heat increases (by in~ 
dubitable laws) as the depth,—it is easy to 
conclude, that the increase of temperature, in 
direction of the depth, cannot result from the 
prolonged action of the sun’s rays; this 
heat is accumulated in the interior of, the 
globe, but) its progress has now almost 
ceased ; for if it continued, we should. ob- 
serve the increase in a directly contrary di- 
rection. The higher temperature of .the 
deeper bed is therefore attributable to internal 
constant, or variable heat. Hence, the tem- 
perature of the earth’s surface is higher 
than would arise from the influence of the 
sun’s rays only. But this has become al- 
most insensible; and we are only assured 
of the fact by mathematical relations of mea- 
sure and excess: for the various observa- 
tions of the earth’s figure being attentively 
examined, according to the principles of the 
Dynamic theories, we cannot longer doubt: 
that this our planet received a very ele- 
vated temperature at its formation, while, 
on the other hand, thermometrical obser- 
yations clearly show that the actual distri- 
bution of heat, on the earth’s surface, is 
precisely what would haye taken place, 
that having been the case, and the globe, 
since, been. constantly cooling. —Bulletin 
Universel. 
Barometer.—Baron Humboldt has con- 
structed a set of tables to show the horary 
vibrations of this instrument, from the leyel 
of the sea to the height of 1,400 toises, 
about 8,952 feet. 
Venus, when viewed through a teles- 
cope, is rarely seen to shine with a full face, 
but, like the moon, increasing, decreasing, 
horned, gibbous, &c. : her illuminated part 
being constantly turned toward the sun, or 
directed toward the east, when a morning, 
and toward the west, when an evening star. 
These phases of Venus were first’ dis- 
covered by Galileo ; who thus fulfilled the 
prediction of Copernicus: for when this 
excellent astronomer. revived the ancient 
Pythagorean system, asserting that the earth 
and planets moved round the sun, it was 
objected that, in such a case, the phases of 
Venus should resemble those of the moon; 
to which Copernicus replied, that, some 
time or other, that resemblance would be 
found. Galileo sent an account of the dis- 
covery of these phases, in a letter, written 
from Florence in 1611, to William de Me- 
dicis, the duke of Tuscany’s ambassador at 
Prague, desiring him to communicate it 
to Kepler. The letter is extant in’ the 
preface to Kepler’s Dioptrics, and-a-trans- 
lation of it in Smith’s Opties.. ‘Having 
recited. the observations he had’ made, he 
adds, 
