T H E J O U R S A L OF I;t'DCSTKlAL A N D EAYGIAVEERIL'\'G CHEATISTRY.
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of very small quantities of carbon monoxide. The carbon dioxide formed b y the reaction between the
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1912
containing the iodine pentoxide and a special burette has been devised for holding the sample. The burette consists of eight superimposed bulbs, each having a capacity of r o o cc. The constriction between each bulb is calibrated so t h a t any number of bulbs up t o eight can be used for holding the sample. The gas is measured in the burette b y means of a level bottle, in the ordinary manner: a copper-Constantine couple is used for registering. the temperature, about I 5 0 O C., within the iodine pentoxide tube. These and other devices designed a t the Bureau of Mines for examining gases will be fully described in a forthcoming bulletin prepared by the author and his associate. F. M . Seibert.
AN IMPROVED EXTRACTION APPARATUS. By \Ir C RLASDALE Received December 18, 1911.
Fig. 10.-Portable apparatus for the determlnation of carbon dioxide in mine air. Capacity of burette, 20 cc. ; capacity of stem of burette, 3 cc.; capacity of bulb of burette, 17 cc. ; stem of burette graduated in 0.01 cc.
iodine pentoxide and the carbon monoxide is absorbed b y a standard solution of baryta water and the excess of same titrated with standard oxalic acid solution.
P.
Fig 11.-Portable
apparatus used in fighting mine fires and exploring mines after explosions, Capacity of burette, 100 cc., burette graduated in 0.1 cc.
The apparatus as used differs from other types in t h a t a n electrically wound jacket is used t o heat the tube
Many different forms cf cxtraction apparatus, which make i t possible to extract a number of samples with a low-boiling-point solvent siniuitaneously, have been described. .4 feature of all the more satisft-tory forms of such apparatus is the use of electrical energy in heating the flasks containing the solvent at the desired rate. The apparatus here described utilizes electrical energy obtained from a I Io-volt lighting circuit; i t provides for five units, t h a t is, for five separate heating plates and condensers. The general form of the rack used t o support the extraction tubes and condensers is the same as t h a t described b y Hopkins ( J . Ant. Cheiiz. SOC.,21, 645). It differs from the latter in Liint the energy of :he current is changed into heat by passing through resistance wire
instead of through incandescent lamps, the heat thus generated being imparted directly t o the five iron plates upon which the flasks rest. It differs further from any of the forms with which the writer is familiar in t h a t a condenser is attached directly t o the frame of the apparatus, which condenser can be easily connected with any or all of the flasks while still in position on t h e heating plates, thus rendering i t possible
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T H E J O U R N A L OF IiYD G S T R I A L il.\-D
t o distil off and collect the solvent after extraction has been completed and obviating the need of a separate apparatus for this purpose. The details of construction are represented in the three accompanying draw-figures, which represent transverse longitudinal and horizontal projections of the lower portion of the apparatus. The Bed of the Apparatus.-The bed (a of Fig. I ) which supports the five separate units consists of a board 5 x 3/, x 2 4 inches resting on metal cleats, fastened t o the vertical supports as shown in Fig. 2 . Two strips of wood ( b of Fig. I ) 1 3 / ~ x 2 4 inches are nailed t o the extreme edges of this support, and two wooden cleats (G of Fig. I ) 3/4 x I j 4 x 2 4 inches are fastened t o the base as shown in Fig. I . The space between the wooden cleats is covered with a strip of one-sixteenth inch asbestos board, and upon this are placed the five heating plates, which are held in position b y screws passing into the base. The wroden cleats support a copper plate (a’ of Fig. I ) 5 x 1 / 5 2 x 2 4 inches which is provided with five
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The latter was made of block-tin tubing a half inch in external diameter and provided with five lateral upright branches, each soldered in place with pure tin. It terminates in a worm condenser, which is enclosed in a cylinder of sheet copper three inches in diameter placed at the end of the vertical support. Connection between the different flasks and the lateral opposite them is easily made b y means of a glass tube fitted with cork stoppers as shown in Fig. I . The entire device takes u p b u t little room and in no way interferes with the use of the apparatus during extraction. Distillation and extraction can be carried on simultaneously on different heating plates provided the laterals of the condenser which are not in use are closed with cork stoppers. UNIVERSITY OF CALIFORXIA, BERKELEY.
NOTES ON A NEW FORM OF EXTRACTION THIMBLE.’ B y P. A.
BOECK.
Received January 2 , 1912.
circular openings of a diameter slightly greater than t h a t of the heating plates. This plate is not fastened in place and can be readily removed for the purpose of inspecting or repairing the heating device. The Heating Device.-The heating plates were made from the caps used t o close the ends of inch and a half water pipes b y cutting with a hack-saw t o a height of a half inch. These plates are heated b y the current carried b y a nichrome wire 0.01 inch in diameter which passes from a switch attached t o one of the vertical supports through a circuit which includes three complete turns around each of the heating plates. The wire is insulated from the plates b y means of strips of mica: it is held in its proper position b y means of brass clamps fastened t o the bed of the apparatus, each clamp holding two pieces broken from the stem of a Rose crucible, through which the wires are strung. The details of the wiring are best shown in Fig. 3. The total length of wire used was 1 5 0 inches and the total resistance offered was calculated t o be 7 2 ohms. An actual measurement of the current consumed gave one and one-half amperes. All the plates were found t o be uniformly heated and the heat generated was sufficient to cause ether t o boil violently after the switch had been closed for ten minutes. A high boiling-point liquid in one of the flasks attained a temperature of 1 2 5 O, but no difficulty was experienced in reducing this temperature b y interposing a thin piece of asbestos between the heating plate and flask. The Cundemiutg Apparatzts.-A strip of wood (e of Fig. 2 ) 3 / ( x x 26 inches, nailed to the back of the two vertical supports, sustains the condenser.
The following notes have been collected from the experiences of a number of different investigators, using the new type of inorganic extraction thimbles known as “Alundum.” A few words as t o the nature of these thimbles may be of interest: Alundum, the material from which these articles are made, is the product of the fusion of the mineral bauxite (a natural hydrate of aluminum carrying small percentages of iron oxide, silica and titanium oxide) in the electric furnace, in which process partial purification takes place so t h a t the resulting product is essentially pure fused alumina. This material has been used quite extensively for abrasive purposes, replacing emery and corundum, over which it has the advantage of being absolutely uniform and of easily controlled composition. I t can be made to yield an abrasive higher in crystalline alumina and consequently of higher abrasive efficiency than any other form of commercial, natural aluminous abrasive. I n the manufacture of laboratory Ftrticles of this material, the fused alumina is crushed, graded t o uniform mesh, mixed with a small amount of a suitable ceramic bonding material and burned a t a high temperature in an ordinary porcelain kiln, where the bond is caused to vitrify or mature, giving it the strength of an ordinary porcelain body, and a t t h e same time retaining its porous nature, which allows the penetration and filtration of liquids and gases. The porosity of the bodies can be controlled in several ways, which depend, t o a certain extent, on the other physical properties, such as strength thermal conductivity, texture, melting point, expansion due t o temperature changes, shrinkage, etc., which are desired. The three methods most generally used in obtaining bodies of different porosities are: ( I ) b y varying the size of the grain or particles of the alundum, thereby changing the size of the voids; 1 Presented at forty-fifth meetmg of the Amencan Chemical Society. at Washington. December, 191 1
