* 
clination, in reference to tl 
pointed out by General Sabine 
.Presented, i 
A. D. Bache on Declinometer Observaticns. 197 
has not yet been determined but it is certain that this influence is 
cally determined but they were undoubtedly similar in form to 
those before described and entirely different from the octahedral 
erystals noticed above. Is it not possible that all the prismatic 
crystals of zinc, which have been described, including those of 
Noggerath and Rose, may belong to the same crystalline system ? 
If so the apparent anomaly presented by the above facts would 
disappear, and as the observers themselves do not claim that the 
Cambridge, Nov. 14, 1860. 
oy” 
Art. XVII.— General Account of the Results of Part Il. of the ms 
of the Declinometer Observations made at the Girard ol 
6 
ry 
THE 
the am 
aa that 
an ie, . 
resented, is of the annual solar diurnal variation and its annual 
Ax. Jour. Sct—Szconp Sertms, Vor. XXXI, No. 92.—Manrcu, 1861. 
26 oe 
