*2Sti Prof. J. Emerson-Reynolds on Franklandite, 



pnre oil of vitriol was then added, and the liquid diluted with 

 twenty volumes of strong alcohol. Calcic sulphate and most 

 of the sodic sulphate separated out; the* filtrate when evapo- 

 rated, after addition of an excess of pure potassic hydrate, was 

 treated with pure hydrofluoric acid, the mixture evaporated to 

 dryness, and the insoluble salts washed away from the result- 

 ing potassic boro-fluoride by solution of potassic acetate (1 to 

 4 of water) followed by alcohol. Estimation of boric oxide 

 by means of the boro-fluoride is always unsatisfactory, owing 

 to the solubility of the body, and to the large volume of po- 

 tassic acetate solution required for the removal of the saline 

 impurities ; nevertheless it is useful as a check on the indirect 

 determination of the boron compound. The numerical value 

 obtained by the latter method is much more worthy of confi- 

 dence, though probably slightly in excess of the true amount. 



Experiment. 



■ A — - > 



Theory. I. II. III. 



B*0 3 43 * (51 43-76 (by diff.) 41*81 (direct) 



CaO 11-63 12*10 ... 11-94 



Na 2 12-87 12*37 



H 2 28*04 27*92 ... 27*66 



(Na, K)C1 = \ 



0aS0 4 +2aq! \ '" 3 ' 85 



= 1*44 ...J 



96*15 100-00 



If we exclude the impurities present and deal with the 

 residue only (96*15), the analytical data (I.), when discussed 

 in the usual way, lead well to the empirical formula which 

 may be stated thus, according to the custom amongst minera- 

 logists :- 2Na2 ^ 2Ca0 ^ 6Bg Q ^ 15H2 a 



Our insight into the constitution of compound borates is so 

 limited that it is scarcely safe to assign to a new member of 

 the class, as I believe this body to be, a " rational " formula ; 

 nevertheless it is possible to express the composition of the 

 compound in such a way as to exhibit very clearly its probable 

 relationship to Ulexite ; for the two minerals may be thus 

 represented : — 



Ulexite, 

 [2(Na'B0 3 ) + 2 H3 B0 3 ] + 2[Ca"(BO s ) 3 + 2 H 3 B0 3 ] + 9 H 2 0. 



Franklandite, 

 [2Na'B0 2 + 2 Na' B0 2 ] + 2[Ca"(B0 2 ) 2 + 2 H 8 B0 3 ] + 9 IT 2 O. 



1 have ventured to assign to the new mineral the name 



