Philosophical Transactions. 385 
These observations are valuable to the pharmaceutical chemist. 
We wish Dr. Davy would extend his inquiries to the influence 
of yarious agents upon emetic tartar, for the liquor antimonii 
tartarizati of the Pharmacopeeia, and several other solutions 
of that useful antimonial are prone toa decomposition, in which 
oxide of antimony is precipitated. 
9. On the State of Water and Aériform Matter in Cavities found 
in certain Crystals. By Sir H. Davy, Bt., P.R.S. 
It is assumed by geologists that much of the surface of our 
present globe must have once been in a fluid state, but different 
schools have assumed different causes as productive of this 
effect, some referring to aqueous, others to igneous, liquefaction, 
TI have often (says Sir H. Davy,) in the course of my chemical researches, 
looked for facts or experiments, which might throw some light on this in- 
teresting subject, but without success, till about three years ago, when, in 
considering the state of the fluid and aériform matters included in certain 
crystals, it appeared to me that these curious phenomena might be exa- 
mined in a manner to afford some important arguments as to the causes of 
the formation of the crystal. 
Sir Humphry then goes on to reason upon the state of the 
water contained in these crystals, which, if enclosed in them 
at a pressure and temperature not very unlike those of our 
existing atmosphere, ought to fill nearly the same space as 
when included ; if, on the contrary, it took place at a higher 
temperature, a certain vacuum might be expected in the cavity, 
from the contraction of the fluid, and if any air or gas were 
present, a considerable rarefaction of it. Upon examining 
several crystals containing cavities with included water, and 
not permeable to the atmosphere, the cavities were found to 
contain a more or less perfect vacuum; the aériform matter 
was azote, and the water was nearly pure, appearing only to 
have absorbed the chief part of the oxygen of the originally 
included atmosphere. It appears from these researches, that 
the existence of water in crystalline rocks is adverse to the 
Neptunian theory, which it has always been considered to justify. 
Tn an appendix, Sir Humphry describes the existence of a liquid 
resembling naphtha, in a crystal from the magnificent collection 
of C. H. Turner, Esq. He also describes an experiment upon 
a crystal in the collection of the Royal Institution, showing 
that in its cavities, which were very minute, the air, instead of, 
as in all the former cases, being rarefied, was compressed, so 
as to enlarge to 10 or 12 times its original yolume, upon drill- 
ing into the vesicles containing it. 
10. Some Experiments on the Changes which take place in the 
Fixed Principles of the Egg, during Incubation. By William 
Prout, M.D., F.R.S. 
These experiments (says the author,) demonstrate, orrender prokable, 
the following circumstances :— 
Vou, XIV. 22°C 
