T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C B E M I S T R Y
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was t o avoid loss when boiling out the Br. T o this was then added, by means of a pipette, 20 or 25 cc. of a solution of pure NaBr of 7 t o I O per cent strength. A t the same time, using Ihe 5ame p i p e t t e , the same amount of NaBr solution was pipetted into a weighed dish t o serve as a blank. The beaker containing t h e Br was placed on the boiling water bath, and allowed t o remain there until the Br had all boiled off, and most or all of i t had been expelled from t h e solution, when the solution of mixed bromide and chloride was transferred t o another weighed dish, and both t h a t and t h e blank were evaporated t o dryness, the last traces of moisture expelled by heating in air bath a t about 130°, ignited gently and weighed. T h e salts obtained from the “mixed” is less than t h a t from the “blank” by an amount equivalent . t o the difference between the combining weights of CI and Br. I n other words, Blank - Mixed = Diff., and since
(Cl) 35.46
(Br) 7 9 . 9 2 -
= 44.46 44.46 : 35.46 = Diff. : Clpresent. For most purposes, 80 per cent of the difference in weights gives the CI. The contents of t h e dishes should be dissolved separately, and each diluted t o some convenient bulk (say 2 5 0 cc.), and aliquot portions tested by titration with standard AgNOa. The halogen equivalent in the two masses of salts should be the same if no losses have occurred. Applied t o the sample submitted the results were: Taken Wt. of ”Blank” Wt. of “Mixed” Din. = c1’ % CI 6.7249 7.2330 8.4340
1.5884
1.3206 1.1257 1.7434
1.3983 2.0737
0.2678 0.2726 0.3303
0.21364 0,21747 0,26349
3.18 3.06 3.12
Material from a dealer in laboratory supplies marked as Bromine C . P. was found t o contain 0.I q per cent CI. 159 Fsorrr STRBBT, NBW Y o s r CIN
A NEW TYPE OF EXTRACTOR JAMes B McN~ia Received M a y 22. 1916
By
The accompanying diagram illustrates an original type of extractor which has been used successfully in extracting plant material with 86” Bi.. gasoline. Like many other extractors. it consists of three main parts, vie.: a container for t h e solvent, a container for the material t o be extracted, B , and a condenser for the solvent C. This machine, however, has advantages (which the illustration makes apparent) over some other extractors; it is easily cleaned, lacks complications, retains almost all of the solvent, etc. The diagram is drawn proportionally for a machine which has been efficiently used with 86’ B6. gasoline. The use of another solvent, due to a different specific heat, etc., might necessitate a re-proportioning of the parts. e. g., a greater proportionate condensing area or the use of a different variety of substance in the condenser (in this case, copper). The container is a long copper cylinder with a water boiler gauge, ~. SG. attached t o its vertical side near the base. Surrounding the top of the
Vol. 8, No..q
cylinder is a gutter t o serve as a water or mercury seal. This water seal tends t o prevent explosions and the escape of the solvent. The bucket, B , for the material t o be extracted, has a siphon, B S , and an inside wire gauze bucket nearly the same size as B. The bucket i s suspended by chains t o hooks attached t o the lower part of the condenser, C . The condenser, C , consists of a series of truncated cones a t tached (as illustrated) t o a lid. The water inlet is a small pipe, W I , and t h e water outlet a shorter pipe, WO. In operating the machine the solvent is first poured into the container; then the condenser with its attached bucket is lowered into the container. Heat is applied a t the bottom of the container. The number of extractions may be observed by the variations in the level of the liquid in the solvent gauge, SC. RUDOLPII-SPRBCXBLS PHYSIOLOCLCAL L&noa~ronu. UNIVBRSITY oP C ~ l . r w o a N r A . BBXX(BLEY
A SIMPLE AUTOMATIC TIME RECORDER BY MAX MOPISB Received February 4. 1916
No one appreciates more than the laboratory worker any device which eliminates the personal responsibility when many determinations are running a t the same time. The accompanying figure concerns one such device, namely, an instrument which accurately keeps account of the recording of time of beginning experiments, the receipt of samples, etc. The clock, mounted in a nickel frame, operates a rubber dial on the back. Being rubber, there is little incentive to damage the clock, as happens sometimes with those bearing copper dies by jamming the works when making an impression, D i a 1 s are furnished either in 1 2 - or 24-hr. cycles. A key is furnislicd, operating the setting and winding, so that one may wear i t on his chain or bunch of keys and have sole access t o the clock as t o winding and setting, for the key is individual. The ION cost of the apparatus, as compared with the ordinary cumbersome, nonportable type of recording clock-a difference of $z7.5o-is an item for the budget. The clock has been used t o advantage in this laboratory.
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