On Franldandite, a new Mineral Borate. 285 



shown to be in the analysis given further on. The specimen 

 taken for this analysis was carefully picked by myself from the 

 best parts of the mass and the selected portions then mixed. 

 The analytical process was conducted in the following way : — 

 A weighed quantity of the borate was dissolved in pure 

 dilute nitric acid ; to the solution excess of silver nitrate was 

 added, and the precipitated chloride of silver filtered off and de- 

 termined. The excess of silver was then separated from the 

 filtrate by just sufficient hydrochloric acid ; a calculated excess 

 of pure oxalic acid was next added, and the solution then ren- 

 dered alkaline by ammonia. The calcic oxalate thus separated 

 was determined in the usual way. The filtrate from the oxa- 

 late precipitate was then acidulated with hydrochloric acid, and 

 a small quantity of sulphuric acid separated and estimated with 

 the aid of baric nitrate, the excess of the latter being in turn 

 removed by treatment with sulphuric acid. The solution was 

 now transferred to a platinum dish and evaporated to a small 

 bulk, some pure oil of vitriol added, and the heating con- 

 tinued in order to destroy any oxalic acid present. After 

 evolution of gas had ceased, the liquid was allowed to cool and 

 then treated with pure concentrated hydrofluoric acid, and 

 heat applied to volatilize the boric fluoride. The hydrofluoric- 

 acid treatment was twice repeated, and the heating then con- 

 tinued until the temperature ultimately rose to redness. The 

 residue, consisting of sodic and potassic sulphates, was weighed, 

 the potassium present determined with platinic chloride, and 

 from the data obtained the proportion of potassic and of sodic 

 sulphates then calculated. 



The total water was determined by ignition of a weighed 

 quantity of the mineral in a combustion-tube with pure dry 

 litharge ; the water was collected in a calcic-chloride-tube 

 and weighed, the whole operation being conducted as in the 

 ordinary process of organic analysis. 



In order to determine by difference the percentage of boric 

 anhydride in the mineral, the small quantity of sulphate pre- 

 sent was assumed to be in the form of calcic sulphate, while the 

 chlorine found was supposed to be combined with the whole of 

 the potassium and with its equivalent of sodium. The residual 

 sodium and calcium were then calculated into their oxides, in 

 accordance with the general practice of mineralogists. The 

 sum of the percentages of impurities, sodic oxide, calcic oxide, 

 and water, subtracted from the hundred parts, then gave the 

 percentage of B 2 3 by difference. This result was controlled 

 by a direct determination as potassic boro-fluoride, made in 

 the following way. The borate was dissolved in the least pos- 

 sible quantity of dilute hydrochloric acid ; a slight excess of 



