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A bit. XXX I . — -Proceedings of the Cambridge Philosophical 
March 5. 1821.-— A. na lysis of Native Phosphate of Copper 
from the Rhine . By the 31 ev. F. Lunn, B. A. F,R.S. F.C.P.S. 
St John’s Coll. Camb. — Doubts have existed of the accuracy 
of Klaproth’s analysis (the only one yet given,) of this exceed- 
ingly rare mineral, and these receive much confirmation, from a 
considerable quantity of combined water being entirely over- 
looked. In this paper, some analytical difficulties which occur 
in the separation of phosphoric acid are examined. The me- 
thod which appears to agree best with experiments of verifica- 
tion, is to obtain an insoluble phosphate, by the addition of per- 
fectly neutral nitrate of lead. The result obtained by Mr 
Lunn was, 
Experiment. Atoms. Theory. 
Phosphoric acid, - 21.687 1 22.222 
Per-oxide of copper, - 62.847 1 63.492 
Water, . - 15.454 2 14.285 
Hence its chemical symbol is, - C u P -f 2 A q 
and its mineralogjcal - - - C a P -{-% A q 
Dr E. D. Clarke, Professpr of Mineralogy, read a paper on the 
Crystallization of Water, as it was remarkably developed in 
Cambridge, January 3. 1821, and two following days; the crystals 
being of considerable magnitude, and of the rhomboidal form, 
measuring in their obtuse angles 120°. This form the Profes- 
sor considered as exhibiting the primitive form of hydrogen- 
oxide ; because the disposition of the laminae in those crystals 
was evidently parallel to the plane faces of the rhombi. 
March 19. — On Arragonite. By Dr E. D. Clarke. — This 
paper proposed to explain the cause of the different specific gra- 
vities of the several varieties of this mineral ; and proved, that 
the famous Egyptian Soros, discovered by Mr Belzoni in Up- 
per Egypt, which has been considered as of Oriental alabaster, 
is one integral mass of stalactitic arragonite. 
April 2. — A communication from Professor Leslie, F.K.S.E., 
and Hon. Mem. of the Cam. Phil. Soc., was read, detailing some 
experiments made upon Sound excited in hydrogen gas ; from 
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