TRANSACTIONS OF THE SECTIONS. SjT 



phate-of-magnesia solution shows a great tendency to precipitate tlie dibasic 

 phosphate, even if the tiibasic salt is in solution. Phosphate of magnesia-ammonia 

 IS decomposed when used in excess, so that dibasic phosphate of mao-nesia is left 

 in the residue. ° 



The phosphate of copper is less soluble. Tlie solution spontaneously deposits 

 mby-colouredcrystals, Cu^ SO,-f CuO SOj+SHO; but when rapidly heated to 

 the boiling-point, pure phosphate of copper is again formed. 



Phosphate of urauium is sparingly soluble in water charged with sulphurous acid ; 

 and when the solution is heated the phosphate is again precipitated, with its ori- 

 ginal composition. 



The crj'stals of tribasic phosphate of soda, 3NaO, PO,+24HO, absorb a current 

 of S02_with great energy, heat is liberated, and the phosphate melts. After cool- 

 ing, acid sulphite of soda crystallizes ; and the remaining oily liquor is separated, by 

 mixing with alcohol, into two layers, the lower being principally an aqueous solu- 

 tion of acid phosphate of soda, and the upper one an alcoholic solution of acid 

 sulphite of soda. If the crystals of the phosphate are mixed with a little M^ater 

 and then saturated hot with SOj, the clear solution separates, after standing', into 

 two distinct layers, which unite again by shaking. " 



_ The phosphates of baryta, lead, and silver are decomposed by sulphurous acid 

 into insoluble metallic sulphites and phosphoric acid, which is dissolved. 



No other compound of sulphurous acid with a phosphate like the lime com- 

 pound has been obtained. 



The phosphates of stannic oxide, metastannic oxide, and bismuthic oxide are not 

 acted on by sulphurous acid. 



Arsenite of lime, prepared by precipitating ammoniacal solutions of arsenious 

 acid and chloride of calcium, treated, when suspended in water, with sulphurous* 

 acid, gives a solution containing 3 eq. CaO and 1 eq. AsOg, and arsenious acid is left* 

 undissolved. By boiling, the solution is decomposed into sulphite of lime, and 

 arsenious acid remains in solution. 



Vanadiate of copper forms a solution with water and sulphurous acid, which 

 when boiled, forms beautiful yellow metallic scales, containing copper, a lower 

 oxide of vanadium, and sulphurous acid. They tarnish rapidly when exposed to 

 the air. ^ 



Oxalate of lime is very sparingly soluble in water charged with sulphurous acid, 

 and IS deposited unchanged when the latter is driven out by heat. 



Note on the Occurrence of Vanadium. By Dr. B. "W. Gerland. 



The author's friend, Mr. Jon. Donn, discovered a large deposit of a sandstone 

 the chemical analysis of which proved it to contain vanadiate of lead and copper' 

 beside a great number of other metals, also thallium in appreciable quantity! 

 The manufacture of vanadic acid from this ore is not difficult. The author has 

 preparedSJ lbs. of pure vanadic acid from 1 cwt. of picked pieces of the sandstone. 



Vanadic acid is likely to prove useful by its oxidizing property in both neutral 

 and acid solutions. As the lower oxide of vanadium formed in this process is apt 

 to take up oxygen from the air, the vanadic acid can play in solution the part of 

 nitrous acid in the vitriol-chambers. For instance, a solution of 30 grnis. of 

 aniline in hydrochloric acid, mixed with 2 grms. ammonium vanadiate and much 

 water, deposited, after some time, a deep-blue substance, which increased in quan- 

 tity until all aniline had disappeared. The vanadiate was left in solution. 



On Eecij>rocaJ Decomposition viewed ivith reference to Time. 

 By John H. Glabstone, F.R.8., F.C.S. 

 When solutions of two salts are mixed together, it has been foimd that they at 

 once begin to decompose one another; but if the new compounds are themselves 

 soluble in water, the decomposition is never complete, but the four salts remain 

 together in solution in certain proportions, dependent on the strengih of affinity of 

 ea«h base for each salt-radical, and on the actual amount of each. If, however 

 one of the new compounds is insoluble in water, it removes itself from the field of 



