n dioxide 0.0098
Grains per pound 0.6860
Equivalent to stannous chloride 0.8640
Minimum doses 13.6
Maximum doses 1.7

Can eroded

_Serial No. 593._--Sample of canned pineapples, bought of Mr. Brown,
Fifth Avenue, August 4, 1890. Labeled: Florida Pineapple, Oval Brand.
Extra Quality. A Booth Packing Co., Baltimore, Md.

Per Cent.
Tin dioxide 0.0158
Grains per pound 1.11
Equivalent to stannous chloride 1.40
Minimum doses 22.40
Maximum doses 2.80

Can eroded.

--_Jour. Amer. Chem. Soc_.

* * * * *

NEW PROCESS FOR THE MANUFACTURE OF CHROMATES.

By J. MASSIGNON and E. VATEL.

The ordinary method of manufacturing the bichromates consists in
making an intimate mixture of finely pulverized chrome ore, lime in
large excess, potash or soda, or corresponding salts of these two
bases. This mixture is placed in a reverberatory furnace, and
subjected to a high temperature, while plenty of air is supplied.
During the operation the mass is constantly puddled to bring all the
particles into contact with the hot air, so that all the sesquioxide
of chromium of the ore will be oxidized. After the oxidation is
finished, the mass is taken from the furnace and cooled; the
bichromate is obtained by lixiviation, treated with sulphuric acid and
crystallized. This method of manufacture has several serious
objections.

The authors, after research and experiment, have devised a new
process, following an idea suggested by Pelouze.

The ore very finely pulverized is mixed with chloride of calcium or
lime, or carbonate of calcium, in such proportions that all the base,
proceeding from the caustic lime or the carbonate of calcium put in
the mixture, shall be in slightly greater quantity than is necessary
to transform into chromate of calcium all the sesquioxide of chromium
of the ore, when this sesquioxide will be by oxidation changed into
the chromic acid state. The chloride of calcium employed in proportion
of one equivalent for three of the total calcium is most convenient
for the formation of oxychloride of calcium. If the mixture is made
with carbonate of lime (pulverized chalk), it will not stiffen in the
air; but if lime and carbonate of calcium are employed