the Brewsteritc of Scotland^ the StUhife and the Ileulandite, 115 
differences do not exceed 2°^ even those might have she^n that 
the primary form was not that which he had supposed. It is 
however possible, that he might not have measured these planes. 
To enable the reader to compare the Abbe Hally’s figures with 
mine, I have added on three of the planes of Fig. 7. in small 
letters, (scored under thus, 5 , T), the letters he has used to de- 
signate those planes. The measurements on the natural planes 
of this substance frequently disagree on large crystals ; those 
on which I have most relied, have been taken on small crystals 
with the reflective-goniometer, and are as follows : 
z on P, 
lir 15' 
M, 
146 SO 
T, 
148 
M — «, 
114 
T — a\ 
116 
M — T, 
130 
a — ?/, 
no 40 
From these measurements may be deduced the ratios of the 
edges Cjfl ch^ eg of the primary form, which are nearly as the 
numbers 160, 161, 16^. These ratios suppose the planes a 
and z to result from decrements by one row on the edge and 
angle of the primary form which they replace. 
The figures are drawn merely as diagrams, to render the de- 
scriptions intelligible, and with little regard to accuracy of 
form 
Art. ’^Observations on the Impregnation of Wood with 
Sea-Water^ and on the Fogs of the Polar Seas'\’. By Wil- 
liam ScoRESBY, Esq. F. R. S. E. M. W. S. &c. 
I. Impregnation of Wood with Sea-Water. 
It has been my privilege to make a number of experiments 
on the effect of enormous pressure on wood sent to great depths 
* Since I received the above paper from Mr Brooke, 1 have examined the Ra- 
diated Zeolite^ and find it to differ by the most palpable optical characters from 
the Foliated Zeolite which I had examined in 1817. See Phil. Trains. 1818, p. 230. 
— D. B, 
Read before the Wernerian Natural History Society, 17th Nov. 1821. 
