H. Wurtz’ Contributions to Analytical Chemistry. 81 
fourth of that present) appear to be expelled; but as Professor 
Dana has observed in his comments upon allophane analyses,* 
this cag arg of 100° as the temperature sways separating 
essen non-essential water is quite arbitrary, and it ap- 
pers giatetore desirable for the present to consider minerals of 
this class in their natural (air-dried) state. It would perhaps be 
possible to make, without great delay, such a series of experi- 
ments at very gradually i increasing temperatures as should ren- 
der evident some real separation of the bison oe into two 
= more portions, facilitating the escape of w by first reduc- 
ing the mineral to powder. The formula iol by faa 
melsbergt+ for Schrétter’s mineral, (Al5i+12H)+24IH,, brings in 
ao as a proximate constituen 
Ala 
his ama mineral is remarkable as containing a little 
oxyd of zine, Pic rae in Schrétter’s specimens oxyd of copper was 
resent. quantities of oxyd of copper also occur in 
almost all the ‘published analyses of allophane, and would seem 
Rctio acid, which may have afterwards t taken part in the pro- 
Schriitierite speed itherto Seat x0 reported m but a single 
F Es an in Styria—it is shaneating’ again to find it, 
now in this coun am . unable to refer to the original paper 
form 
University of labora, March 6; 1858, 
Arr. XII.—Contributions to Analytical Cheeses; by i. 
4 Wurtz, of New York City. 
(Read before the American —, for pon Advancement of Science, at =e 
Investigation of the action ohh nitrie acid on the metallic hte. 
(Continued from vol. xxv, p. 384.) 
‘ 29. Cerium.—Chlorid of cerium,§ which had a faint pink 
fs tinge due to contamination with chlorid of didymium, and prob- 
: ably con contained also a little: chlerid. of lanthanum, but was other- 
o cited pees ae 131. ¢ Handw.d.chem. Th. d. Min, 8. 18. 
c Proe. porcrhys aber io, ee 
The cerium, um compounds used were 
extremely beauti HINY spect spoctsiens of hig’ ly erytallized ae 
s nerosity of Mr. T. cg unt of the = 
. sulphate if ws oe especially, —— oe early i of an 
SECOND SERIES, Vor. XXVI, No. 76.—JULY, 1858. 
11 
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