^i)Mch fill m Orldney mi the July 1818. BTl 
served to indicate S7;76. The mercurial column had sunk two 
inches; for in the register kept at the Start Point Light-house, 
about a mile from Lopness, the marking at 8 a. m. was 29-68. 
When the cloud had completely passed, Mr Lindsay, student 
of Divinity, ‘ having gone into the garden at Lopness, observed- 
that the ciabbages were perforated as if musket-bullets had 
been shot against them.*” — About an hour afterwards,” he 
adds, T picked up some that still remained uhdissolved, and 
found that they measured 1/^th inch in diameter. They were 
for the most part of a spheroidal form, consisting of a nucleus 
resembling common hail, , occupying about |d of the diameter, 
encrusted by a coating of transparent ice. Some of the stones, 
however, were • irregularly formed into a soft of crystallized 
mass.” 
Aet. Abstract of Mr Herschel's Experiments on 
Circular Polarisation 
In the Sd volume of this Journal, p. 897. we have already 
given a brief abstract of the important results contained in Mr 
Herschel’s paper on circular polarisation ; and our readers will 
find in Vol. II. p. 179? 180. a short notice of what had been pre- 
viously done on the same subject "I. 
Mr Herschefs memoir is limited to an examination of the 
properties of that variety of quartz to which Haiiy has given 
the name of plagiedre. One of these crystals is represented in 
Plate VII. Fig. 7., where the faces a-, a*, a*, and a^, a?', a^, pe- 
culiar to this variety, lean, as it were, in one uniform direction 
round the summit A, which is adjacent to them, the angle form- 
ed by these faces, and the adjacent sides of the prism, being 
greater on one side (the right, for instance,) than it is on the 
other. If the summit a is placed uppermost, by inverting the 
crystal, the plagiedral faces adjacent to this summit obey the same 
law, and turn in the same direction. 
* This ingenious paper, read April 17. 1820, will immediately appear in the 
Transactions of the Cambridge Philosophical Society, vol, i. 
•)- See also p. 4!21. of this ^Number. 
A a 
