46 



REPORT — 1870. 



On an Attempt to determine the Boiling-point of the Saturated Solutions of 

 various Salts by boiling with Steam of 100° C By Peteb Spence, F.G.S. 

 The author stated that he had been engaged in a series of experiments with the 

 view of determining the boiling-points of the saturated solutions of various salts, 

 by blowing into these solutions steam of 100° C, and taking the highest point 

 of temperature attainable by this means as the boiling-point of the saturated solu- 

 tion of the salt operated upon. This was following out into practical results the 

 discovery brought by the author before the Exeter Meeting, that steam of 100° C. 

 gives mucli higher temperatures than its own in such solutions. Several difficulties 

 were alluded to ; but these the author hoped to overcome, and concluded by giving 

 a list of solutions that he believed are determined with an approach to accuracy. 



Nitrate of potash . . . 113-6 



Sulphate of ammonium . 108'6 



Nitrate of soda ... 1 18-8 



Chloride of ammonium . 114-1 



Chloride of sodium . . 109-4 



Chromate of potash . . 106-6 



Chloride of barium . . 105-0 



Sulphate of copper . . 105-2 



Sulphate of magnesia . 105-5 



Carbonate of potash . . 129-4 



Sulphate of soda . . . 104-4 



Chlorate of potash . . 105-5 



Sulphate of potash . . 102-7 



Oxalic acid 111-9 



Sulphate of alumina , 105 



Nitrate of lead . . . 104-7 



Bichloride of mercury . 100-5 



Chloride of potassium . 109-4 



o F- 

 236-5 

 227-3 

 246-2 

 237-5 

 229 

 224 

 221 

 221-5 

 222 

 205 

 220 

 222 

 217 

 233-5 

 221 

 220-5 

 213 

 229 



Chloride of manganese . 

 Acetate of barium . . 

 Chlorate of barium , . 

 Binoxalate of potash . . 

 Carbolic acid .... 

 Chromic acid .... 

 Nitrate of silver . . . 

 Phosphate of soda . . 

 Sulphate of zinc . . . 

 Nitrate of baryta . . . 

 Nitrate of strontia , . 

 Tungstate of soda . . . 

 Ferrocj^anide of potassium 

 Chloride of zinc . . . 

 Iodide of potassium . . 

 Sulphate of niclcel . , 

 Carbazotic acid . . . 



On the Discrimination of Fibres in Mixed Fabrics. By J. Spilleb, F.C.S. 



In the course of an experimental inquiry undertaken for the purpose of identify- 

 ing the fibres entering into the composition of mixed fabrics, the author was led to 

 the discovery of the fact that sillc alone, of all the materials ordinarily used in the 

 production of textile fabrics, is soluble in concentrated hydrochloric acid. The 

 chemical properties of the silk solution so prepared were described, and a photo- 

 graphic application pointed out by the author, who exhibited in this connexion a 

 matt-paper print, which was stated to have been produced in a much shorter time 

 than that commonly required for an ordinary print on a plain salted paper. A 

 hydrochloric-acid solution of silk was used, which, being made as concentrated as 

 possible, and neutralized by addition of ammonia, furnished a new organic chloride, 

 particularly suitable for salting paper intended for solar camera enlargements. For 

 the purpose of identifying wool in the presence of cotton, flax, jute, &c., it is re- 

 commended to immerse the fabric or loosened fibres in a warm aqueous solution of 

 picric acid, which dyes the wool of a bright yellow without imparting any colour to 

 cotton. Thus, by treating a mixed fabric successively with hydrochloric and picric 

 acids, valuable indications are aflbrded regarding its constitution. 



On Marbles from the Island of Tyree. 

 By Edward C. C. Stanford, F.C.S. 



The author exhibited some polished specimens of two kinds of marble from the 

 Island of Tyree, in Argyleshire. One of these is unknown elsewhere. It is a beau- 

 tiful pink marble with dark green spots, which are crystals of hornblende. The 

 pink colour is duo to peroxide of iron, which is scarcely soluble in dilute hydro- 

 chloric acid. The other is a white compact magnesian limestone, containing suffi- 



