1816.] _ . during the Year 1815. 33 
5. Zinc.—Vogel has published a set of experiments on zinc. The 
following are the results which he obtaiued. The black powder 
which remains when zinc is dissolved in sulphuric acid consists of 
charcoal, iron, and sulphate of lead. He could not obtain any 
more than one oxide of zinc, and therefore denies the existence of 
the supposed protoxide of zinc obtained by Clement and Desormes 
and by Berzelius. ‘The flowers of zinc of the apothecaries always 
contain less or more carbonic acid. There exists a subsulphate of 
zine, which is sparingly soluble in boiling water. 
6. Arsenic.—A great number of experiments have been lately 
made on the solubility 6f white oxide of arsenic in water. Those 
of Klaproth have been published in a preceding volume of the 
Annals of Philosophy. A still more complete set of experiments 
were afterwards published by Professor Bucholz.- But the most 
elaborate of all are those of Mr. Fischer, a public teacher in the 
University of Breslau. They occupy no less than 40 pages in 
Schweigger’s Journal (vol. xii. p. 155). The results at which he 
arrived are as follows. 
White oxide of arsenic is insoluble in water. Its solution takes 
place only when it is changed into an acid by combining with a 
greater proportion of oxygen, which it absorbs at the expense of 
the undissolved portion. Hence the reason why the undissolved 
portion loses its white colour, and becomes of a dirty yellow. This 
change takes place at all temperatures between that of the common 
temperature of the atmosphere and that of boiling water. 12'343 
parts of boiling water dissolve one part of this substance ; between 
-the temperatures of 122° and 144°, 22 parts of water are necessary 
to dissolve one part of this substance ; between the temperatures of 
66° and 77°, 50 parts of water are necessary; while between the 
temperatures of 45° and 50°, 66°6 parts of water are necessary to 
produce this solution. ‘To obtain the solutions in these proportions, 
a very long action of water upon white arsenic is necessary. 
7. Tungsten.—A set of experiments on tungsten by Bucholz, 
made some years ago, but promised in the historical introductory 
discourse of last year, have been published in the Annals of Philo- 
sophy (vol. vi. p. 198). He shows that the methods hitherto fol- 
lowed to obtain tungstate of ammonia do not furnish that salt in a 
state of purity, and,that the impure salt does not yield the metal 
when smelted in the usual way, but runs into a slag. This is pro- 
hably the reason why so few chemists have succeeded in obtaining 
tungsten in the metallic state. Bucholz obtained it in that state. 
He was not able to fuse it; but he confirmed the previous experi- 
ments of the Elhuyarts and Allen and Aiken respecting the great 
specific gravity of this metal. He found its specific gravity 17-4, 
which is a mean between the results obtained by the Elhuyarts 
(17°6) and Allen and Aiken (17-2). 
8. In a late number of the Annals of Philosophy (vol. vi. p.'75) 
it was stated that Brugnatelli had formed an amalgam by exposing 
Vou. Vil. N° I, 2 
