Notices respecting New Books. 303 
to separate by mechanical force. This observation has been re- 
peatedly verified upon carbonate of lime, selenite, fluor-spar, 
quartz, topaz, and other mineral bodies. 
“ The foregoing experitnents and observations are offered. in 
support of the ingenious theory of Dr. Wollaston, whose simple 
and satisfactory elucidation of the principles of crystalline ar- 
rangement has solved the difficulties, and remedied the incon- 
sistencies of all previous explanaticns of the phenomena. Former 
hypotheses, however laborious in their construction, were defec- 
tive, and unsatisfactory in the fundamental data of their arrange- 
ment, and were incompetent even to explain the solitary fact from 
which they originally emanated. 
** This, however, is found:to stand the test of experiment, as 
far as it is applicable from the nature of the subject ; and another 
analogy is thus opened to the admirers of the simplicity and 
beautiful connexion of the order of the universe, who will recog- 
nise, in the invisible and scarcely imaginable atoms of a crystal, 
the same forms which in incomprehensible magnitude roll their 
majestic courses in the planetary system.” : 
The other articles in the number before us are :—4. Ona sin- 
gular malformation of the human Heart; by N. L. Young, Esq. 
—®}. Some account of the external changes which take place in 
the Surinam Frog (Runa paradoxa Linn.) from its earliest stages 
till it becomes a perfect animal ; by W. M. Ireland, Esq.—6. An 
account of the physical properties of the Malambo Bark.—7. A 
new blow pipe.—This contrivance consists in employing a vessel 
containing compressed air, and furnished with a syringe to renew 
the supply. 
8. On Aqua regia, or Nitro-muriatic Acid: By Sir H. Davy. 
—Strong nitrous acid, saturated with nitrous gas, and mixed 
with a saturated solution of muriatic acid gas, produces no other 
effect than might be expected from the action of nitrous acid of 
the same strength on an equal quantity of water: the acid so 
formed has no action on gold or platina. Equal volumes of mu- 
riatic acid gas and nitrous gas being mixed over mercury, and 
half a volume of oxygen being added, the condensation will only 
- be what might be expected from the formation of nitrous acid 
gas; and when decomposed or absorbed by the mercury, the mu- 
riatic acid gas, unaltered, is found mixed with a portion of nitrous 
gas. ‘It appears then, that niérous acid and muriatic acid gas 
have no action on each other.”” The mixture of colourless nitrie 
acid and muriatic acid of eommerce is yellow, and dissolves gold 
and platinum. If gently heated, it gives off pure chlorine, and 
becomes deeper coloured; if the heat be continued, chlorine still 
rises, but mixed with nitrous acid gas, which may be separated 
from it by a small quantity of water, If heated till no more 
chlorine 
