TRANSACTI01>JS OF SECTION B. 589 



in acid. Should the time have been too short, particles of ore will be visible in the 

 bottom of the fused mass after removal from the crucible, and the mass must then 

 be replaced and agam heated. Unless the time of heating has been prolonged, it is 

 safer to dissolve all up in sulphuric acid, oxidise with a few drops of permanganate 

 solution any unoxidised chromium salt, and remove excess of permanganate by 

 sodium carbonate and alcohol. A temperature for fusion so high that the crucible 

 TDecomes attacked by the fluxes is quite unnecessary. 



8ATURDA Y, ' SEPTEMBER 3. 

 The Section did not meet. 



MONDAY, SEPTEMBER 5. 

 The following Papers were read : — 



1. On certain Points in Modern Progress in Chemical Knowledge. 

 By Professor H. B. Armstrong, Pli.B., F.B.8. 



2. On the alleged Decomposition of the Elements. 

 By Professor Dewar, M.A., F.B.S. 



3. On the Production of Crystals hy the Action of Metals in Carbon 

 Bisulphide in Sealed Tules. By Philip Braham, F.C.S. 



The mode in which the experiments were conducted was by sealing up fifteen 

 different metals in carbon disulphide, and carefully examining them with the 

 Tnicroscope. The tubes exhibited were put up on June 20, 1879, examined on 

 June 20, 1880, and in May, 1881, transparent crystals were found in those which 

 ■contained gold, antimony, and bismuth. 



4. On the Separation of Hydrocarhon Oils from Fat Oils} 

 By Alfred H. Allen, F.C.S. 



The extensive production of various hydrocarbon oils suitable for lubricating 

 purposes, together with their low price, has resulted in their being largely employed 

 for the adulteration of animal and vegetable oils. The hydrocarbons most com- 

 monly employed for such purposes are — 



1. Oils produced by the distillation of petroleum and bituminous shale, having 

 a density usually ranging between "870 and "915. 



2. Oils produced by the distillation of common rosin, having a density of "965 

 ■and upwards. 



3. Neutral coal-oil ; being the portion of the products of the distillation of 

 coal-tar boiling at about 200°C., and freed from phenols by treatment with soda. 



4. Solid -paraffin ; used for the adulteration of bees' wax and spermaceti, and 

 •employed in admixture with stearic acid for making candles. 



The methods for the detection of hydrocarbon oils in fat oils are based on 

 the density of the sample ; the lowered ^flashing and boiling points ; the fluorescent 

 ■character of the oils of the first two classes ; and the incomplete saponijication of 



' Published in full in the Chemical News, vol. xliv. p. 161. 



