INDUSTRIAL A N D ENGINEERIATG CHEMISTR.Y
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charges and the resulting combination of the chromium and the collagen. But, as has been shown, all chrome liquors capable of tanning do not contain this negatively charged chromium complex, and consequently this theory cannot hold generally, if indeed at all. That a negatively charged chromium complex exists in certain basic chromium sulfate solutions is established, but that it is responsible for tanning has not yet
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been proved. It is proposed to investigate the chemical nature and the tanning properties of the chromium-containing, negatively charged complex, as time and opportunity permit. ACKNOWLEDGMENT The writer's thanks are due to Prof. Arthur W. Thomas for his kind advice and criticism in the course of this investigation.
A New Absorption Bottle for Carbon Dioxide and Moisture' By William E.Morgan COLUMBIA UNIVERSITY, NEW YORK, N. Y.
HE SUBJOINED sketch illustrates an absorption bottle for moisture and carbon dioxide determinations, which has been found very convenient in organic chemistry work a t Columbia University. The dominant aim in designing this new bottle was to retain the advantage of employing a solid absorbing agent, such as soda lime, without undue complication of manufacture and consequent high-selling price, or excessive weight of container and consequent inconvenience and inaccuracy in weighing. The simplicity of the design is manifest. The weight empty is somewhat under 50 g., which permits filling two-thirds with moist soda lime and one-third with calcium chloride without exceeding generally a filled weight of 80 g.; filled with calcium chloride it is generally less than 70 g. I n order to charge the bottle for carbon dioxide absorption, it is set, bottom up, on its flat top, the requisite amount of soda lime is introduced, a cotton or perforated rubber diaphragm is inserted, if desired, and the calcium chloride added. The ground joint a t the base is greased, the cup base adjusted, and the bottle, when inverted, is ready for use. The gas current is led in a t the top, and passes out through the long tube embedded in the charge. Two combustions can always be made with such a filling, and checks may be obtained even when the charge materials have remained in contact for several days. For example, on the same filling the following results were obtained a t this laboratory:
T
Date November 21 November24
the soda lime rather than inside a tube surrounded by soda lime,, tends t o minimize temperature fluctuations in the absorption efficiency of the calcium chloride corresponding to the temperature changes of the reacting soda lime. With ordinary care the bottle is more durable than other heavier vessels, since the small diameter and absence of protuberant stopcock handle on the top permit a firm grasp of the sidearms while attaching rubber connections, thus obviating breakage a t the seal-in of the side arms-a frequent accident with beginners. The full bottle may be handled by the upper half without danger of the cup base falling off, provided the ground-glass joint has been properly greased. The absence of external attachments facilitates wiping to constant weight. If stuck, all joints are conveniently accessible to the loosenIng action of warm water.
Found Calcd HnO Con H C H C Sample G. G. % % % % 0.1998 0.1039 0,4992 5.69 68.14)5.73 68,26 0.2700 0.1372 0.6760 5.69 68.28
And ' on another filling, three. successful combustions were made. as follows: Found Calcd. coz C C
Date December 12 December 14 December 16
Sample 0.2348 0.2249 0.2159
G. 0,4753 0.4191 0.4191
%
%
55.21 52.84 52.94
55 26 52.72 52.72
A cotton diaphragm divided the charge materials in these runs, Nothing could better illustrate the practical uselessness of introducing ground-glass valves, with their attendant weight, difficulty of fitting, and liability to sticking, for the purpose of separating calcium chloride and soda lime between runs. Special experimental work with a perforated-rubber septum also shows that the migration of water from soda lime to calcium chloride may be ignored. Other advantages of the simplified bottle may be briefly mentioned. The accessibility of every part of the container to vigorous mechanical action facilitates removal of the exhausted charge. The position of the calcium chloride, below 1 Received
January 23, 1923.
It is then believed that this bottle represents a distinct improvement over other existing designs with respect to ( a ) lightness of weight , combined with reasonable capacity of chamber, (6) simplicity of manufacture, (c) convenience in filling, emptying, wiping, and manipulating generally, and (d) durability under ordinary conditions of use. For continuous work involving the absorption of relatively large amounts of carbon dioxide, as in organic combustions, it has given entire satisfaction.
