A COLLECTOR FOR DISTILLATION OF AMMONIA FROM WATER. BY F P. D C X X I S G T O S Receired F e b r ~ a r i2, ,898
I
N the familiar process of making a determination of free and albuminoid ammonia in water, the close attention which is demanded to change the receptacle as each of the several portions of fifty cc. is collected, is soniewhat engrossing to anyone when conducting other analytical work. To avoid this embarassment I have devised the following simple apparatus, which, for lack of a better name, is called a collector.
The figure presents a section of one-fourth size. From this the arrangement and working of the apparatus may be understood. I t is made as follows : I n a block of dry poplar or other light wood, A, 43 X 53 X 150 mm., a hole of three mm. diameter is made at B for the pivot, and the l a w e hales. CC. for Nessler tubes. are alaced a t the
COLLECTOR FOR DISTILLATION.
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same distance from the center of the block and equally inclined, a s indicated. When the Nessler tubes are twenty-nine mm. in diameter, these holes should be about thirty-one mm. and be lined with a strip of woolen cloth to afford a snug fit for the tubes. T h e pivot B is a knife edge, made by grinding at its ends, a piece of a double three-inch saw file about fifty-five mm. long, and is merely hammered into the small hole cut for it. T h e knife edge is supported by a pair of plain two-inch angle irons (such as are kept in stock a t a hardware store); in each of these, the hole in the upright limb is bored out and filed to the shape shown in the figure. These irons, D, arescrewed to the wooden base, E, 170X 170x20mm. T h e motion of the block, A , is checked by two round-head screws fastened into the under side of A, and by two flat-head wood screws partly screwed into the block E. By screwing the latter up or down you may adjust the apparatus so that when one tube is empty and the other is being filled, as soon as the latter collects fifty cc. of water, it topples over and immediately brings the other tube under the point P, to collect the distillate. While the second tube is being filled, you may hold the block A , remove the first tube and empty or replace it by another tube of same size and weight ; when the second tube has collected fifty cc. it will topple over and again bring the mouth of the empty tube under P. T h e screw which serves to fasten each angle iron in place also passes through one end of a slip of thin sheet brass 15x30 mm., the other end of which is bent up a t right angles, so serving to keep the pivot from shifting to one side, but not binding upon. it. T h i s piece of brass is not shown in the figure, since it would cover the pivot end. T h e Nessler tubes used are 29 mm. in diameter and 195 mm. long, and weigh 49 grams; should the tubes be heavier, it would be necessary to bore the hole for the pivot a t a point a little higher up on the center line of the block A. I t is easy to adjust this apparatus so that the amount required to topple the tubes will not vary a s much as one-half cc. from the fifty cc. UNIVERSITYOF VIRGINIA,February a, 1898.
