430 MEMOIR OF THE LATE DR THOMAS CHARLES HOPE. 
the first on the 23d of January, the last on the 3d of April. The author, from 
the action of different re-agents on infusions of these flowers, established the 
existence in each of a distinct proximate principle, which, however, he had been 
unable to exhibit in a separate state; to these he gave the name of Camelline, 
Magnoline, and Chrysanthemine. He shewed, also, that notwithstanding the fine 
white of the petals of Camellia Japonica, they contained much iron. 
The second paper, his last communication, was read on the 1st of May 1843, 
the very last time that Dr Hore was ever at the meetings of our Society. It 
is styled “An Attempt to explain the Phenomena of the Freezing Cavern at . 
Orenburg.” 
This cavern is described by Sir Ropertck Murcuison, as one of several 
occurring in a low hill of Gypsum. In winter, the air of this cavern feels warm 
to those who enter it; but in summer an intensely cold air issues from it. This 
has been explained by Sir Jonn HERscHEL, as being produced by the long time 
the waves of heat and of cold take to penetrate to the interior of the cavern— 
each requiring six months to penetrate to that depth; just as SAussuRE found, 
that it required, at Geneva, six months for the heat of summer, or the cold of 
winter, to penetrate to the depth of 294 feet. While admitting this general ex- 
planation, Dr Hore considered that it would require something more to explain 
the forcible issue of such cold air during the summer months; and he makes an 
ingenious conjecture, on the part performed by the air cooled in the fissures, 
described as existing in the inmost recesses of the cavern, in producing that 
phenomenon. 
The subject is very interesting though obscure ; but I may observe that such 
streams of cold air are not peculiar to the Orenburg cave. Streams of air, cooled 
from 15° to 34° below the external air in the shade, are known to issue from the 
crevices of the small artificial hill at Rome, named Monte Testaccio ; from the 
limestone grottos of Cesz, in the Roman states, so well described by Saussure, in 
Journal de Physique for 1776; from the caves in the sandstone hill, on which is 
perched the miniature republic of San Marino ; from the Cantines in the potstone 
rock near Chiavenna; from the caverns of Caprio, on the Lake of Lugano; 
and from the calcareous caves of Hergisweil, at the base of Mont Pilate, nearly 
opposite to Lucerne. What is still more extraordinary, such cold caves exist in 
countries the seats of not yet extinguished volcanic fire. Sir Wir~1Am HAMILTON 
describes the cold winds issuing from the cave of Ottajano, at the base of Vesuvius; 
and in the Isle of Ischia, the air which issues from the Ventarola of Funera is as 
cold as 48° F., when a thermometer in the shade, without the cavern, is at 58°— 
(See Saussure, Voyages dans les Alpes, IIT. 1405.) 
Such are the chief contributions of Dr Hors to physical science. 
It has been alleged that they are fewer and less important than we had 
reason to expect, from the long period during which he filled the Chemical Chair, 

