Miscellanies. 151 
much as the hard. ‘The author made numerous experiments of this 
description. ‘The absorbent nature of the leaves renders i. difficult 
to compare, with accuracy, waters differing little from each other. 
The effect of pure water, he says, is very near to that of any nat- 
ural water, containing carbonate of sdda, but the soda is supposed a 
little to increase the quantity taken up, as well as the sensibility of 
the palate—Jour. of Royal Inst. Vol. I. p. 42. 
6. On the limits of vaporization, by M. Farapay, F. R. S.— 
A series of experiments has been performed by this distinguished 
chemist to ascertain whether there are actually definite limits to the 
force of vaporization. Even when water becomes ice, the ice evap- 
orates, and there is no cold either natural or artificial, so intense as 
entirely to stop the evaporation of water, or in the open air to pre- 
vent a wet thing from becoming dry. é: 
The question which the ingenious author sought to determine was 
whether, as appears to be the opinion of Davy, Dalton, and others, 
every substance, (even the most solid) has an atmosphere of its own 
nature about it, and diffused in its own neighborhood. ‘This atmos- 
phere, in the case of fixed substances, as the earths and metals, might, 
twas thought, be so feeble as to be quite insensible even by extraor- 
dinary examination, and yet, rising into the atmosphere, may produce 
peculiar results, 
Some former investigations of the author induced him to suppose 
that we possess a great number of substances which are perfectly fixed, 
and no portion of whose substance rises into vapor under any ordina~ 
'Y Citeumstances of temperature. re 
In September, 1826, several stoppered bottles were made perfect- 
ly clean, and several wide tubes, closed at one extremity, so as to 
smaller vessels capable of being placed within the bottles, were 
Prepared. ‘Selected substances were then put into the tubes, and 
Solutions of other selected substances in the bottles; the tubes were 
Placed in the bottles so that nothing could pass from one substance to 
the other, except by vaporization. The stoppers were introduced, the 
€s tied over carefully, and put away in a dark safe cupboard, 
Where they remained undisturbed for four years. ‘The most impor- 
‘ant results were the following. 
.»% 1. Bottle—clear solution of sulphate of soda with a drop of 
mitre acid ; tube—crystals of muriate of baryta. One half the 
Water passed into the tube, and formed a solution of muriate of ba- 
ryta. No trace of sulphate of baryta in either. 
