OF ARTS AND SCIENCES I OCTOBER 13, 1868. 63 



To hold dissolved 1 part of sulphate of lead in the dilute alcohol 

 charged with sulphate of ammonium, there was consequently required 

 110 c. c. of a tolerably strong solution of acetate of ammonium. 



Still another experiment with sulphuric acid was made by mixing 

 10 c. c. of an entirely new preparation of acetate of ammonium with a 

 similar quantity of the standard solution of acetate of lead, and drop- 

 ping the standard sulphuric acid into the mixture. No persistent pre- 

 cipitate was produced in this case until 5 c. c. of the acid had been 

 added. This quantity of the standard acid contained 0.049 grm. of 

 sulphuric acid corresponding to 0.1515 grm. of sulphate of lead ; 

 hence only 33 parts of the solution of acetate of ammonium were re- 

 quired to dissolve 1 part of sulphate of lead. It is to be observed that 

 the insolubility of tartrate, citrate, and succinate of lead in alcohol pre- 

 vents the application of this modified form of the experiment in the 

 examples given below.. With the exception of the acetates of am- 

 monium and sodium, none of the salts experimented with can be mixed 

 with the acetate of lead and subsequently tested with sulphuric acid or 

 sulphate of ammonium. 



Acetate of Sodium, whether mixed with the normal sulphuric acid ? 

 with sulphate of ammonium, or with acetate of lead, seemed to have 

 no solvent action upon sulphate of lead. 



Neither Oxalate of Ammonium nor normal Oxalate of Potassium 

 exerted any solvent action either in presence of the sulphuric acid or 

 the sulphate of ammonium. 



Tartrate of Ammonium. — Normal, crystallized tartrate of ammonium 

 was dissolved in alcohol of 18%, in such proportion that 500 c. c. of 

 the solution contained -^ of an equivalent, 18.4 grms. of the salt. 25 

 c. c. of the solution was mixed with an equal volume of the normal 

 sulphuric acid, and normal acetate of lead was added to the mixture 

 until a permanent precipitate was produced. To effect this result, there 

 was required of the standard solutionof acetate of lead 2 c. c. or 

 0.0758 grm. of the acetate, corresponding to 0.0606 grm. of sulphate 

 of lead. The 25 c. c. of the solution of tartrate of ammonium contained 

 0.92 grm. of the dry salt. Hence, something more than 15 parts of 

 tartrate of ammonium are required to hold 1 part of sulphate of lead 

 dissolved in dilute alcohol containing free sulphuric acid. 



In two other experiments where the tartrate of ammonium solution 

 was mixed with the sulphate of ammonium instead of with free sulphuric 

 acid, 3 c. c. of the acetate-of-lead solution had to be added before a 

 permanent precipitate could be formed. 



