Prof. Miller on the Forms of Sulphur et of Nickel, Sfc, 105 



by these lines, or 90° — OT, being measured, the resulting 

 value of O T was between 48° and 49°. In the same man- 

 ner the angle between the axis of the prism and the intersec- 

 tion of T T, was found to be nearly 61°. By a number of 

 observations made with the reflective goniometer, O R was 

 found equal to 20° 50'. Now, 3 tan 20° 50' = tan 48° 47', 

 and 4 tan 48° 47^ = cotan 61° 17'. Hence it appears that 

 the value of O T was measured with sufficient accuracy to be 

 used in finding the symbol of T. 



O (1, 1, 1), Q(l, 1, 0), R (1, 0, 0), S(2, 2,-1), M (1,1, -2), 

 T(4,4,— 5), V (-1,— 1,4), L (4,1, -5). 



2'4S2 grains of the mineral weighed 2*012 grains in distilled 

 water at 15° C. In a second experiment 2*431 grains were 

 found to weigh 1*969 grains in water at the same temperature. 

 The resulting specific gravities are 5*280 and 5*262. 



Sulphate of Oxide of Copper and Ammonia. 



Cu S + 3 H N S + 7 H. 



Oblique prismatic. A(1;0;0), C(0;0;1), P(l;l;l), 

 Q(l;-l;l), H (0; 1 ; 1), M(1;1;0), T(2;0;l). 



AT = 41°12i' <^ P — a^f^oQi-lf 



TC = 64 54 



CA =73 534 



MM =108 56 



AM = 35 52 



PP =139 37 



HH =127 39J 



QQ =140 16^ 



AQ = 48 13^ 



CH = 26 lOi 



AH = 75 35 



When yellow light is refracted through the faces T C, the 

 Third Sei'ies, Vol. 6. No. 32. Feb. 1835. P 



