THE ANALYST. 97 NOTE ON THE DETERMINATION O F ALCOHOL I N E'fHElt AXD CHLOROFORN. By ALFRED H. ALLEN, F.C.S. Rend 7jt$ore the Society of Public AnaJysts, at Plymouth, 17th August, 1877. SEVERAL chemists have pointed out that crystallized fuchsine (acetate of rosaniline,) was insoluble in pure anhydrous ether or chloroform, but that it imparted more or less colour to these liquids when alcohol was present.On making the experiment 1 found that fuchsine readily coloured a sample of commercial ether. When thc same sample mas well agitated with dry chloride of calcium t o remove alcohol and water, it lost thc power of dissolving fuchsine, becoming tinged only very faintly, when shaken with the dye. To employ the above facts for the determination of alcohol in a sample of ether, I operate in the following manner :- A minute quantity of powdered fuchsine is placed at the bottom of a narrow test- tube, 10 C.C.of the sample of ether added, the tube corked and the whole agitated. If the ether be pure and anhydrous the coloration of the liquid mill he almost nil. If the coloration be considerable, 10 C.C. of ether which has been treated with chloride of calcium, is placed in another tube of the same bore as the first, adding fuchsine as before.25 C.C. of alcohol is then added t o it from a finely divided burette, and the whole is shaken. I f this quantity of alcohol is insufficient t o produce a coloration of the liquid equal to that of the sample to be tested, a further addition of alcohol must be made until the liquids have the same depth of colour.The tint is best observed by holding the two tubes side by side in front of a window and looking through them transversely. The use of a piece of wet filter paper behind them facilitates the observation. It is well to permit the alcohol to drop right into the ether, and not allow it t o run down the sides of the tube, as in the latter case it mill dissolve any adherent particles of fuchsine, forming a solution which will be precipitated on admixture with the ether.For a similar reason it is not convenient to dilute the sample with pure ether so as to reduce the colour to that of a standard tint. I n practice, each ?a C.C. of alcohol added from the burette may be considered as indicating 1 per cent. of impurity in the sample.Of course this assumption is not strictly correct, but the error introduced is insignificant when the percentage of alcohol is small. The method is very suitable fgr small proportions of alcohol, but becomes difficult to apply when the latter exceeds 5 Fer cent. of tho sample, owing to the intensity of the colour. The results are within 3 per cent. of the truth. Occasionally the tints of the two liquids are not readily comparable, but on placing the tubes for a few minutes in cold water, this difficulty is overcome.I n attempting to apply the above method to the determination of alcohol in chloro- form, I found that the latter liquid still dissolved fuchsine after treatment with chloride of calcium, By shaking with concentrated sulphuric acid it could be entirely purified from alcohol and water, but the product retained so much acid that it could not be directly tested with fuchsine. The acid could be got rid of by agitation with carbonate of potassium, but the chloroform so treated retained sufficient alkali to prevent the coloration by fuchsine.By employing dry precipitated carbonate of barium to eliminate the sulphuric acid, the chloroform was obtained so pure as to give only a very slight coloration with fuchsine, but the addition of a small proportion of alcohol readily caused98 THE ANALYST.solution of the dye with production of the characteristic colour.s The method commonly described for determining the proportion of alcohol in ether is the agitation of thc sample with Tvater, with subsequent observation of the diminution in the bulk of the ether.This method appeared very unpromising in presence of much alcohol, but on inrestigati3g it, I was agreetbly surprised to find that with certain precautions, it was possessed of considcrable accuracy. The following are the details of the procedure I have found preferable. A. small quantity of fuchsiiie is placed in a Mohr’s burette furnished with a glass tap, which is then filled with water and a small proportion of ether, n cork is next introduced, and the whole agitated. By this means a coloured etherized water is obtained, in which ether is quite insoluble, while al(aoho1 readily dissolves.10 C.C. of the etherized water are run into a glass tube holding about 25 c.c., and having divisions of &. c.c., 10 C.C.of the sample of ether arc next addcd, the tube corked, and the whole well shaken. Any reduc- tion in its volume is due t o admixture of alcohol. Thus each 0.1 C.C. lost, represents 1 per cent. of alcohol. If the proportion of alcohol in the sample did not excced 20 per cent., the ether will be colorless, and the result of the experiment is correct ; but if the proportion of alcohol is much above 20 per cent., thc layer of ether is COlOUred, and the result is below the truth.Thc absence of coloiir therefore indicatcs the accuracy of the experiment. I f the layer of ether be coloured, an accurate result can still be obtained by adding 5 C.C. of anhydrous ether, and again agitating. I t is better, however, t o dilute a fresh portion of the sample with an equal bulk of pure ether, and use the diluted sample instead of the original. By proceeding in this manner, the proportion of alcohol in mixtures of that liquid with ether can be ascertained within 1 or 2 per cent.with great facility. I n all cases the proportion of alcohol must be deducted from the reduction in the volume of the ether, and not from the increase in that of the aqueous liquid.Care must be taken to prevent any volatilization of the ether. On the ether rising t o the surface, its T-olume can be easily read off. The process has been verified up to 60 per cent. of alcohol. * I n attempting to find a coloring agent more suitable than fuchsinc for use with chloroform, methyl- aniline-violet was tried, with the curious discovery that this substance is cxceedingly soluble in chloroform, with intense yiolrt colour. So grcat is the affinity of methyl-aniline violet for chloroform, that this liquid readily removes it from its aqueous solution, when agitated with it, Mr. G. Jarmain informs me that he has obscrved the same fact, and has employed it for detecting the adulteration of indigo with methyl-aniline violet.