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POPULAR SCIENCE REVIEW. 
great expense, it becomes a question whether the addition of wood spirit to 
alcohol will any longer prevent its being employed in the manufacture of 
spirituous drinks, so that the ultimate result would seem to be disadvanta- 
geous rather than otherwise, for it will put a stop to the sale of methylated 
spirit, free of duty, for the manufacture of varnish and other commercial 
purposes. 
M. Regnault has described a method of recording the temperature and 
pressure in balloon ascents, without observation of the aeronaut. The 
apparatus consists of a series of tubular reservoirs, with capillary tubes 
proceeding from them ; at the end of each capillary tube a larger tube, 
filled with chloride of calcium is fixed, so that only dry air can enter the 
reservoir. These constitute the thermometric system. The barometric 
consists of a similar series, with their reservoirs immersed in melting ice. 
In order to insure the temperature of the ice remaining constant in the 
extreme cold of the upper regions, it is recommended to surround the 
vessel containing the ice with another vessel containing warm water at 
starting. The tubes are numbered to correspond in each series. To deter- 
termine the temperature and pressure at any moment, it is necessary to 
close the stop-cocks of one tube in each series simultaneously, the balloon 
not being in rapid motion at the time. The density of the air contained in 
the tubes is afterwards determined, from which both the temperature and 
pressure at the time of closing can be deduced. 
YEAR or two ago no geological doctrine was believed to be better 
demonstrated than that which declares granite to be a fire-formed 
rock. The generalization agreed well with the theory known as Laplace’s 
— really Sir W. HerschePs — of the consolidation and cooling of the 
earth from a fiery state, which most mathematicians and geologists 
accept ; and was submitted to such complete discussion in the famous 
war of Wernerians and Huttonians, that the possibility of the idea being 
imperfect or wrong was never suspected. In the days of its adoption, how- 
ever, and indeed till recently, the earth’s crust was regarded as a mere egg- 
shell of some ten miles thickness, which any Plutonic disturbance might 
pierce ; but latterly the central fluid mass has been placed at greater and 
greater depths, till now there is probably no one who regards it as likely that 
fluid rock is forced up to the surface of the earth from its centre. Then came 
the researches of Mr. Sorby on the microscopic structure of igneous and 
intrusive rocks ; and, as is well-known, the occurrence of cavities con- 
taining water and a bubble of air, in their constituent crystals, led him 
to conclude that the temperature at which granite was produced could not 
have been excessively high, and that water in a heated state was not absent 
from it when formed. And now Professor Harkness has added further to 
the evidence, and drawn a most important conclusion, destined we believe 
to be generally adopted. Whilst examining metamorpliic strata in the 
highlands of Scotland, he has found that the strike of the Plutonic masses 
corresponds with that of the metamorphic rocks, and accordingly infers 
GEOLOGY AND PALAEONTOLOGY. 
