412 Scientific Intelligence. [May 
part of a lofty dense Cumulostratus, which happened to present, in 
the N.E. at near five p.m. a surface directly opposed to the sun, 
which perceptibly reflected an image of the disk at the same appa- 
rent height from the horizon. In a few minutes, and almost as 
soon as I had satisfied myself of the fact, it was obliterated by a 
new protuberance in the cloud destroying the direct reflection. An 
Anthelion observed by Swinton near Oxford in 1762 is described, 
with a figure, in Vol. XI. of the Phil. Trans. Abridged, p. 532, 
to which the reader is referred; but in the present instance, the 
whole cloud being bright, the contrast between the general surface 
and the sun’s image was prebably less striking than in Swinton’s 
observation. 
Tottenham, Fourth Month, 22, 1817. 
XIV. New Earth. 
Professor Berzelius has just discovered a new earth, to which he 
has given the name of thorite, from the Scandinavian god Thor. 
I shall take a future opportunity of laying an account of its proper- 
ties before my readers. 
XV. New Method of Freexing Water. By Professor Leslie. 
(To Dr. Thomson.) 
SIR, 
My early experiments had proved that garden mould and decayed 
green-stone, which constitute the basis of our richest soils, acquire, 
when thoroughly dried, a power of absorbing moisture almost equal 
in intensity, though not in extent of action, to the energy exerted 
by the concentrated sulphuric acid itself. Circumstances recently 
drew my attention again to this curious subject. I directed my 
servant to gather some of the shivery fragments of porphyritic trap 
from the sides of the magnificent walk now forming round the 
Calton Hill, and having pounded it grossly, to roast it moderately 
before the kitchen fire under a tin oven, and then throw it into a 
wine decanter with a glass stopper. In this state of preparation, 
the powder was afterwards carried to the College; and, ata lecture 
some days since in the natural philosophy class (which, in addition 
to my own mathematical classes, I have been teaching this session 
during the absence of Professor Playfair in Italy), I took occasion 
to show the influence of its absorbing power on my hygrometer 
placed over it within a small receiver of an air-pump. ‘The liquor 
of the instrument fell from 90° to 150°, and rose again to 130, 
where it stood fora minute, while the lint covering the wetted ball 
was turning whiter, and evidently freezing, but again regularly 
descended to about 320°, the temperature of the room being only 
about 55° of Fahrenheit. A cold had thus been produced corres- 
ponding to 5° below the zero of that scale; and | did not hesitate 
to propose on the instant to employ this new agent in freezing a 
small body of water. I transferred the powder into a saucer about 
seven inches wide, and placed a shallow cup of porous earthenware 
