26 CHEMISTRY. 
for chlorine a greater affinity than is exhibited by aluminum: this meta 
will thus be left separate, and resembling iron in general appearance. First 
of all, then, to replace the oxygen of the alumina by chlorine. For this, as 
well as many other purposes, we employ the apparatus represented in 
pl. 31, fig. 10, where A indicates a small furnace on which the matrass B 
is heated. In this is placed a mixture of powdered oxyde of manganese 
and hydrochloric acid, which, when heated, will generate chlorine for some 
hours: c is a safety-tube to prevent the bursting of the matrass by any 
obstruction in the tube ee. The chlorine developed passes through the glass 
tube, d, into the cylinder C, half filled with water, in which it deposits the 
impurities brought from B, and thus purified goes into the porcelain tube, 
ee. Into this tube have previously been introduced small cylindrical pieces 
of alumina, prepared by mixing with a solution of sugar or paste, and baking 
in a covered crucible until the sugar or paste is completely carbonized. 
The furnace, D, which, after being filled with coal, and fired up, is covered 
with its top, I, is intended to bring the alumina in the tube to a red heat. 
At this temperature the former affinities are suspended, and the oxygen of 
the alumina combines with the carbon of the carbonized sugar, forming 
carbonic acid; the aluminum being left in a metallic condition, is 
immediately seized by the chlorine. The chloride of the aluminum being 
liquid at a red heat, flows into the cooled receiver, f, attached to the end of 
the porcelain tube, ee; the gaseous carbonic acid likewise escapes 
through the tube g. 
V. Cuemican Examination or Oreanizep Bopizs, AND THE APPARATUS 
NeEcESsSARY FOR THIS PuRPOSE. 
The material forming the bodies of plants and animals is known as 
organized or organic, in contradistinction to the inorganic matter found in 
the mineral kingdom. Excepting the hard parts of the animal, as the 
bones, teeth, &c., and the ashes of the plant, which latter form a very 
slight percentage of its mass, the principal part of the animal body consists 
of but four elements: nitrogen, oxygen, carbon, and hydrogen; and of the 
vegetable, but three: oxygen, carbon, and hydrogen. The method of 
manipulation by means of which we may ascertain the amount of the 
individual elements in an animal or vegetable body, will be briefly 
described, and may serve as an example of the complicated and laborious 
investigations necessary for the purpose. Let the problem be, carefully to 
ascertain the proportions in which the four elements enter into a portion of 
animal matter, or the three into a part of a plant. The first requisite in 
solving this problem is a very accurate weighing of the amount of the 
substance to be subjected to analysis. All substances, however, in contact 
with the air, absorb a certain amount of watery vapor through their pores, 
which necessarily requires a careful drying of the body as an absolutely 
necessary preliminary to this weighing, else we should be in error by 
the weight of the water contained, which would be dissipated in the course 
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