172 



PROCEEDINGS OF SECTION B. 



v.— Nickel Crucibles for the Lawrence Smith Method op 



DBTERMESriNG AxKALIES IN SiLICATES. 



These nickel crucibles, Fig. 5 (price 3s. each) were obtained 

 through Messrs. Gallenkamp and Co., of London. They are used by 

 students in place of expensive platinum ones (about £8 each), for the 

 determination of alkalies in silicates by decomposition with CaCOs 

 and NH4CI. The same Bunsen burner and stand are used as with 

 the platinum ones. 



ng.5. 



The crucibles are acted on by the CaCOs and NH4CI during the 

 heating, but all the nickel is removed in the first operation (dissolv- 

 ing in water and filtering), and causes no further trouble. 



Duplicate determinations, using the nickel crucible in one case 

 Rud the platinum crucible in the other, give the same results. 



