Account of seme remarkable Hail- 8 tones. 329 
by laws of fracture in crystallised bodies, which interfering cir- 
cumstances at the surface of the earth prevent us from observ- 
ing clearly. The probable cause of fracture may be found in 
the expansion of air in the opaque nucleus, in electricity, or in 
centrifugal force. The first of these I should think perfectly 
equivalent to the force required, if it be assumed that a small 
degree of heat may be transmitted by the solid surface from 
without..” 
Art. XV . — Analysis of the Radiated Celestine^ from Norten , 
near Hanover. By Edward Turner, M. D. Member of 
the Mineralogical Society of Jena, Fellow of the Royal Col- 
lege of Physicians, and Lecturer on Chemistry, Edinburgh. 
rp 
JL HE subject of this analysis was examined a few years ago 
by M. Gruner of Hanover *, who found it to differ from all other 
known species of celestine, in containing a large quantity of the 
sulphate of baryta. M. Gruner, who has given an account of its 
geognostical relations, describes it as occurring in a coarse- 
grained floetz limestone, in which it forms three distinct parallel 
beds. In the first bed, the mineral is fresh ; in the second, it 
has a weathered appearance ; and, in the third, though the ra- 
diated texture is still visible, it is in a state of such complete 
disintegration, as to fall into an earthy, chalky powder, from the 
least pressure. M. Gruners analysis gives for a result, in round 
numbers, 
Sulphate of Strontian, ... 73 
Sulphate of Baryta, ... 26 
The weathered variety, on the contrary, was found to contain. 
Sulphate of Baryta, . . . 74- 
Sulphate of Strontian, ... 24- 
The unusual peculiarities of this celestine induced me to sub- 
ject it to analysis, not as doubting the accuracy of M. GrunePs 
observation, but with the desire of investigating the process of 
* See Gilbert’s Annalen, voL lx. ; or Annals of Philosophy for 1820. 
