508 report— 1878. 



FRIDAY, ATJGUS1 16, 1878. 

 The following Papers were read : — 

 1. Notes on Aluminium Alcohols. By Dr. Gladstone and Alfred Tribe. 



In 1876 the authors described the joint action of aluminium and iodine on 

 alcohol, and two aluminium ethylates which resulted from it. They now showed 

 that a similar reaction takes place with methylic alcohol, especially when the 

 aluminium is rendered more powerful by conjunction with deposited platinum ; arid 

 that an analogous aluminium compound is still more readily formed from amylic 

 alcohol. These two substitution products had not yet been prepared in a pure con- 

 dition, but the authors had succeeded in preparing the butylic compound in a satis- 

 factory manner. This aluminic butylate is a solid body at the ordinary tempera- 

 ture, but melts when heated, and is capable of distillation. It is very soluble in 

 anhydrous ether or benzole, from which it separates on evaporation, but without 

 crystallising. It is decomposed by water, butylic alcohol and alumina being pro- 

 duced. Its composition was found to be Al 2 (C 4 H O) ci . ' There is also evidence of 

 an intermediate compound, soluble in water, which is probably homologous with 

 the aluminic iodo-ethylate, A1 3 I 3 (0.,II 5 0)3. 



2. On the TSsti/niation of Mineral Oil or Paraffin Wax when mixed with 

 other Oils or Fats.* Bij William Thomson, F.R.S.E. 



Mixed oils are now often used for lubricating purposes, and a common mixture 

 composed of mineral oil with some animal, vegetable, or fish oil is extensively 

 used, and it is an important point to be able by analysis to determine the amount 

 of mineral oil which such mixtures contain ; and as I could find no published pro- 

 cess to effect this, I devised, after much work, the following, which I found by 

 repeated tests to give accurate results : — Some of the sample is boiled with an 

 alcoholic solution of caustic soda, which converts all the animal, vegetable, or fish 

 oils into soap. This is then mixed with sand, evaporated to dryness on the steam 

 bath, the residue placed in a bottle and washed with petroleum spirit, which has 

 been previously distilled at a temperature not exceeding 190° Fahr. This dissolves 

 out the mineral oil, leaving the soap insoluble. The spirit is now distilled off from 

 the spirit solution in a large flask, and after thus evaporating off the bulk of the 

 spirit, the concentrated solution is transferred to a smaller flask with a hole blown 

 in its side, into which is fitted a cork carrying a thermometer and a glass tube ; 

 the thermometer should touch the liquid, going nearly to the bottom of the flask, 

 which is placed on a sand bath and heated at a temperature not exceeding 

 220° Fahr., and dry air blown into the flask through the tube in the cork, to 

 remove the last trace of spirit, and the residue of mineral oil weighed and cal- 

 culated on the weight of original mixed oil taken. A small correction must be 

 allowed for an amount of unsaponifiable oil which so-called saponifiable oils always 

 contain, but this is about 0"6 per cent, of the saponifiable oil found. 



* 'Chemical News,' Vol. XXXVIII., No. 984, Oct, 4, 1878. 



