Trans. N. V. Ac. Set. 32 A'ov. 13^ 



Solubility of Willemite. 



Specimen. Locality. Amount Dissolved. 



No. I Mine Hill 22.53 P^*" cent. 



No. 2 Franklin 32.23 " 



No. 3 Mine Hill 28.43 



No. 4 Franklin 34.08 " 



Average 29.32 " 



Time i hr. 30 min. 50 per cent, acid ; 50 per cent, water. 



Comparing these various solubilities, we arrive at the following con- 

 clusions: 



1st. That Frankliniie, if pure, is practically insoluble. 



2d. That Red Oxide of Zinc is entirely soluble. 



3d. That Rhodo7iite is slightly soluble. 



4th. That Willemite is partially soluble. 



5th. That the Carbonates, etc., are almost totally soluble. There- 

 fore in the solution from the treatment with acetic acid, there would be : 

 silica, from the Willemite and Silicate of Manganese, oxide of man- 

 ganese, in small quantities, and oxide of zinc, from the Red Oxide and 

 Willemite, provided a definite method of treatment be adopted, and all 

 contact with the acid be avoided, as soon as examination shows that 

 the red particles in the ore are dissolved. 



The following method of analysis was therefore adhered to : 



A. Sampling. — Crushing and quartering through three successive 

 stages, until the sample was sufficiently fine for analysis. 



B. Method. — Weigh out two grms. and treat with a mixture of 

 acetic acid and water (fifty per cent. No. 8 acetic acid, and fifty per 

 cent, of water). Allow to stand approximately one and one-half 

 hours, examining occasionally under a powerful magnifying glass ; 

 heat gently, if any red particles are visible, a-nd continue the treatment 

 until no red oxide is contained in the residue. Filter and wash. 



Residue A. Solution A. 



Dry and weigh on Acidify with HCI, and evaporate to 



weighed filter. dryness; take up with HCI and 



water ; warm, filter and wash. 



Residue B. Solution B. 



Silica — dry, ignite Neutralize wiih NaoCOs, acidify with 



and weigh. acetic acid, and precipitate with H3S 



gas. 



