1819.] Scientific Intelligence. 381 
mixture under the receiver of an air-pump with sulphuric acid. 
When separated from water and concentrated as much as pos- 
sible, its sp. gr. is 1-417. It destroys or whitens all organic 
substances. When a drop of it is allowed to fall upon oxide of 
silver, the oxide is decomposed, with explosion, and often with 
emission of light. 
Ill. Wavellite. 
From Sir H. Davy’s analysis of this mineral, it has been con- 
sidered as a hydrate of alumina. The want of the usual ratio 
between the water and the alumina led Berzelius to suspect the 
presence of an acid in it. He accordingly subjected it to an 
analysis which he found attended with much greater difficulty 
than he had anticipitated. He succeeded, however, at last, and 
found it a subphosphate of alumina mixed with a little neutral 
fluate of alumina. The following is the result of an analysis : 
DRTEMMOTENS OA Bierce Se cesld aweldia &.a'6.6 oye 35°35 
TOG Tt Deena amas baa Bnet 30°40 
Pidaic acid), aia\n\h.4b% ose wat joe 2°06 
Bs hes Seca nis he ATER ey Le a rear 0°50 
Oxides of iron and manganese ...... 1:25 
Re er 8 be No feat Ta ... 26°90 
99-46 
IV. Plombgomme. 
A mineral, known by this name, which is found at Huelgéet, 
has been hitherto considered as'a compact wavellite. Berzelius 
subjected it to analysis, in order to ascertain whether it was also 
a phosphate of alumina. He found its constituents as follows : 
Atnminas 2) Ws EL SSS US EERO ct Uitaes 37:00 
Onde of leade +s... 05'S 306563. -.-. 40:14 
TAGE ast. \sconsta talents od o's Foie BEE OE Bates 19-90 
Sulphuric acid win. ies cc OS 0-20 
Oxides of manganese andiron...,... 1°80 
DMCA ok weuetinn CSN oO ee ted ¢ P2250°60 
99-64 
It is, therefore; an aluminate of lead with water of combina- 
tion, just as spinelle and gahnite are aluminates of magnesia and, 
of zinc, but without water. Sulphuric acid appears to have pene- 
trated it in small quantity during its formation, and appears to 
be equally united with the alumina and the oxide of lead. This 
is the first example of this acid occurring in a mineral not 
volcanic. 
V. Euclase. 
' The constituents of this rare mineral, according to a recent 
analysis of Berzelius, are as follows : 
