Per Cent. 
Tin 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 at the same time, the mass stiffens like cement, and can be moulded into bricks or plates.  The best way to operate is to mix first a part of the ore and well pulverized chalk, and slake it with the necessary concentrated chloride of calcium solution; then to make up a lime dough, and mix the two, moulding quickly.  The loaves or moulds thus formed are partially dried in the air, then completely dried in a furnace at a moderate temperature, and finally baked,