THE ANALYST. 131 CRYSTALLIZED GLYCERIN. (Meeting, April 3, 1895.) Mr. Bevan exhibited some specimens of crystallized glycerin. He said that some time back a sample of glycerin had been submitted to him, which consisted of a mass of small crystals resembling soft sugar. He had found that by dropping a small quantity of the crystals into ordinary glycerin kept at a temperature of about 15" C., fresh crystals could be growii at a considerable rate. DISCUSSION. The Chairman (Mr. Otto Hehner) thought that, since commercial glycerin was not anhydrous, the glycerin above the crystals (unless the crystallized glycerin was a hydrate, which he believed was not the case) would become more and more dilute as the crystallization increased. I t was remarkable that glycerin should crystallize out of an aqueous solution, since it was only anhydrous glycerin that was supposed to crystallize.* This seemed to suggest that glycerin was a crystal- line substance in a state of supersaturation, the occasional upsetting of which showed the glycerin in its true state.He would like to know whether an actual crystal was absolutely necessary to start the crystallization, or whether anything else would serve 8s a nucleus. Mr. BEVAN said that the glycerin above the crystals, or mother-liquor, so to speak, was weaker than the original glycerin, and of course much weaker than the crystals. The case was different, however, from that, for instance, of water, which, when cooled down below its congealing point, crystallized in a solid mass the instant it was touched, whereas, in the case of glycerin, the process required a considerable time. He had never been able to obtain crystallization except by starting with an actual crystal. Professor Dewar had obtained glycerin in R solid mass resembling glass, by cooling with the aid of solid carbonic acid and ether. * Since speaking, I hare analysed both crystals and mother-liquor. The former are pure anhydrous glycerin ; the latter contains 6 per cent. of water.-O. H.132 THE ANALYST. ~ ~ _ _ _ _ _ _ _ _ Mr. BODMER said that a sample of glycerin existed some years back in the There was no mother- dispensary at Guy’s Hospital, which was absolutely solid. liquor at all, the material being exactly like a piece of ice.