WORK OF THE CHEMICAL LABORATORY 
By N. W. Lord. 
INTRODUCTION. 
The routine work of the laboratory and the general methods used in making the chemical 
and analytical tests on the samples of coal and other fuels tested at the fuel-testing plant, 
continue to be essentially the same as during the St. Louis Exposition and are described in 
the reports covering that period, a 
NEW EQUIPMENT. 
The temporary laboratory employed during the Exposition was very crowded and incon- 
venient owing to the limited space at the disposal of the fuel-testing plant for this work. 
Since that time the work has been done in a new laboratory fitted up in the foundry building 
left by the Exposition. This new laboratory is larger, more convenient, and better equipped 
in every way for the work, and materially facilitates accuracy and uniformity of results. 
Under the head of "New equipment " may also be mentioned, for the analytical work, two 
additional analytical balances, an extra combustion furnace for ultimate work, an extra 
steel bomb for calorimeter work, and two calcium-chloride drying ovens of special design 
for the moisture determinations; for the sampling work, an especially designed drying oven, 
for facilitating the drying of the samples to a nearly air-dry condition, and a four-jar labora- 
tory ball mill (manufactured by the Abbe Engineering Company), for final pulverization 
of the sample. These are mentioned more in detail under "Changes in methods." 
During the Exposition city gas was used as a laboratory fuel. After the close of the Expo- 
sition this was not available and, as a consequence, gasoline gas is at present used in the 
laboratory. The machine used for supplying the gas is furnished by the Federal Gas Com- 
pany, of St. Louis, Mo., and so far has proved satisfactory. 
CHANGES IN METHODS. 
Tn general the methods employed in the work have been only slightly changed from those 
in use during the Exposition. However, certain modifications have been introduced, fol- 
lowing out lines developed in the experimental work of the laboratory. One of the most 
important of these is in regard to the preliminary or air drying of the samples. The earlier 
method of exposing the sample to the air of the laboratory proved unsatisfactory owing to 
the extremely varying moisture conditions resulting from the general character of the 
weather; the air drying loss in different samples of the same coal varied greatly, though it was, 
of course, accompanied by corresponding changes in the residual moisture of the coal and 
therefore did not materially affect the final statement of the analysis of the sample as 
received. In order to make determinations of the loosely held moisture more uniform and 
definite, a special drying oven has been designed and introduced into the laboratory; in this 
oven samples of several pounds weight can be dried in a gentle current of air raised from 10° 
to 20° above the temperature of the laboratory. In this way the coal is air dried in an 
a Bull. U. S. Geol. Survey No. 261, 1905; Prof. Paper U. S. Geol. Survey No. 48, 1906. 
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