420
NOTES.
(4) Nuclei appear to be the principal exciting cause of crystal formation when other conditions are favorable. These nuclei are soap crystals or particles and possibly other substances. Experiments are now in progress in regard to this point. ( 5 ) S o t too great viscosity or this may overcome the crystallizing forces. Iiapid desiccation may entirely prevent crystal formation. ( 6 ) Shock produced b~7 blows or pressurc act favorably on crystal Formation in many cases. In conclusion, crystal formation, while it does not reduce in any degree the detergent poiwr of a soap, renders it more or less unsalable to i i public which buys according to the appearance of goods. 'l'he experimental work det:tiled above was undertaken it1 order to examine systcmaticall!- the causes of crystal forniation in transparent soap and to provide a remedy. I'III:\IIC.AI.
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NOTES. Rupitl l l c f r i nun,utioiL oJ Ptdrolezim Nahlatha in :'urpenlinc----To dett,rrnine thc :+mount of pctroleuni naphtha in a suspected sample of ttirpentine, i o cc. are carefully ineasurcd into a 50 cc. carbon tube, which is graduated into tenths of a cubic centimeter. Thirty citbic centimeters of aniline are xiow added and the mixture violently s1i:ikcn for f i \ ~ : minutes, and left to settle until the liquid has become perfectly clear, when, if there is aiiy petroleum naphtha present iii the turperitinc, it irill bc throlvn out of solution and Coat in a layer on top, and the percentage can be readily ascertained. I get escellcrit results from this method, but care must be exercised that the aniline does not contain any water. HENRY C. FREY. L S 2 I KEYSOI.DS
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Dcdcrim'viution o j Sodiuiiz tznd Potassium in .Silicntes.-\i;e have found the following. method of determilling sodium and potassium in clay and silicates which call he decomposed by sulphuric and hydrofluoric acids, r'ipid and satisfactcjry. One gram of clay is deconiposed by nieans of sulphuric and hydrofluoric acids, and the escess of sulphuric acid expelled in a hot air bath. TIN: resitl~ir is then dissolyed in water and' powdered barium hydroxide added to the boiling liquid to alkaline reaction. 'l'he solution is decanted a ~ i dfiltered am! tlic resitluc boiled a,vairi with water and thoroughly w,ishccl. Carbon dioxide is passed into the filtrate in excess, the solution e\-,iporated to ,jO cc., ?,< ec. of alcohol (96 per cent.) added.
