. Journal . ion for formaldehyde was often (d>taincd with ethylalcohol alone or with distillates containing no methylalcohol. Jt was not possible to detect small amounts withcertainty. Tlie bichromate methods were found to bethe most i-eliable, under certain conditions, though, atbest, they are neither simple nor rapid. Since the bichromale-sulphuiic acid mixture w iU not onlyproduce methylal and formaldehyde, but w ill oxidise methylalcohol completely (»•) to carbon dioxide and water, the use of a weak solution of chromic acid suggested it«iTrials were made with its solutions of varj-ing c
. Journal . ion for formaldehyde was often (d>taincd with ethylalcohol alone or with distillates containing no methylalcohol. Jt was not possible to detect small amounts withcertainty. Tlie bichromate methods were found to bethe most i-eliable, under certain conditions, though, atbest, they are neither simple nor rapid. Since the bichromale-sulphuiic acid mixture w iU not onlyproduce methylal and formaldehyde, but w ill oxidise methylalcohol completely (»•) to carbon dioxide and water, the use of a weak solution of chromic acid suggested it«iTrials were made with its solutions of varj-ing conccntition and without the customary sulphuric acid. Tlresults were encouraging. Digestion at (iU° C. was at fir])racti8ed, but was later found unnecessary. The mtlhod.—In the method finally devised, oxidati>is made with a weak solution of chromic acid, free acid. The acid is mixed with a small volumethe 8ami)le and the liquid at once distilled. The distillais tested for air condenser. Tlie nearly horizontal f^ertionR are 16 ins. to 181ns. long; the nilddlr. 14 ins.; tubing, ] in. It was thought that an air condenser which of a wooden test tube hohler secured in a small mclamp. Of the numerous tests for formaldehyde, the niodifitHehners test was selected, and when tised as here directsgave complete satisfaction. laqiuds containing otli>substances should, of course, be distilled direct or afterdilution with water. By using another air cnnden-this distillation is ])erformed with expedition, only •l.*) driqis of the distillate being requirid. liiiujinis Chromir ncid solution, in distill)water, containing 0-8 i)er cent, of CiOj, free from sulnhuracid. Albumin solution.—The white of one fresh e(is mixed with .50 of distilled water, filtered, and prserved with
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
