158 PROCEEDINGS OF SECTION B. 



13.— ISO-RET'ENE. 



By Prof. T. H. EASTERFIELB and R. E. RUDMAN, M.A. 



[Abstract.] 



By heating sulphur with colophony, retene CigHis has been 

 obtained by various chemists, notably Kelbe, Tschirch, and Veslei'berg. 

 Other chemists have stated that another substance melting at 85'86 

 (Retene melts at 98'5) is produced, and have ascribed such formulae 

 as (CioH]^i)x and (C5Hg)y to the compound. 



Investigation has shown that the second substance to which the 

 authors ascribed the name iso-retene is produced if the sulphur be 

 present in large quantity, but that with the quantity of sulphur 

 mentioned in Kelbe's paper on resin oil retene is formed. 



Numerous analyses and moiecuiar weight determinations, carried 

 out with carefully purified material, have shown that iso-retene, like 

 retene, has the formula CigHig. It differs from retene in solubility, 

 melting point, and in the colour and melting point of its picrate and 

 the quinine which it yields upon oxidation. Like retene quinine the 

 quinine from iso-retene gives the orthodiketone reaction, so that it is 

 probable that it still retains the phenanthrene structure. 



14.— THE PHASES OF SULPHUE. 



By CLARA M. TAYLOR, M.A., Government Research Scholar in Victoria College, 

 Wellington, N.Z. 



[Abstract.] 

 A sample of commercial benzene handed to me for investigation 

 left a crystalline deposit on evaporation. On examination under the 

 microscope this residue was found to consist of two kinds of crystals. 

 The outer part of the deposit consisted of needles, while in the middle 

 the crystals were of octahedral form. The residue thus obtained from 

 the benzene proved on further investigation to be sulphur. It is a 

 well-recognisfcd fact that when crystallisation can occur in more than 

 one fonn, the inetastable phase is the first to appear. In this case, 

 apparently during the more rapid evaporation, the metastable mono- 

 clinic form is deposited, while during the slower evaporation the stable 

 octahedi'al form is the one produced. The fact that crystallisation had 

 occurred in the manner described suggested the possibility of devising 

 a lecture experiment in which the ciystallisation of sulphur in more 

 than one form from the same solution could be demonstrated. If a 

 cold saturated solution of sulphur in benzene or toluene be diluted with 

 its own volume of the solvent, a cubic centinjetre of this solution 

 placed on a watch glass gives a crystalline deposit of sulphur when 

 spontaneously evaporated. This deposit, when examined under the 

 microscope, is found to have the appearance indicated in the diagram. 



