40 
SCIENTIFIC SOCIETIES. 
to their influence—tlie number of skeletons seen lying about the valley, bleached 
to the whiteness of ivory—go far to furnish foundation for a dreadful tale : and 
such are the actual scenes visited and described by Mr. Loudon. This gentleman 
is inclined to impute the poisonous nature of the air in the valley rather to veget¬ 
able miasmata than to the emission of carbonic acid gas from the ground. Col. 
Sykes is of a different opinion, and assigned his reasons. 
HORTICULTURAL SOCIETY. 
Amongst the plants exhibited at a meeting of this Society, of the 7th of March, 
were the following :—Splendid specimens of Dendrohium fimhriatum D. Pieradi^ 
and D. pulchellum^ from Messrs. Loddiges ; a new species of Callistemon^ from 
W. Harrison, Esq.; Ipomsea Horsfallice, &c., from Mrs. Lawrence ; Andro- 
medajiorihunda^ &c., from Mr. Glenn y ; and a Rhododendron RusseUianum, from 
Mr. Gaines. Messrs. Loddiges obtained the Society’s large silver medal, and 
the other exhibitors respectively the silver Knightian medal. Many other beauti¬ 
ful plants were exhibited; and the usual distribution of grafts of esteemed and new 
varieties of fruit took place.—The following is the statement of the extreme con¬ 
ditions of the barometer and thermometer, and the amount of rain observed in the 
Society's garden since the 21st of February:— 
Barom. Highest, March 1..... 80.431. 
Lowest, Feb. 23... 29.324. 
Thermom. Highest, Feb. 21. 54° Fahr. 
Lowest, Feb. 25. 28° 
Total amount of rain. 0.21 in. 
LINNAEAN SOCIETY. 
Feb. 21.—A. B. Lambert, Esq., Y.P. in the chair.—Mr. Iliff exhibited part 
of an Oak tree, which had been blown down during the late hurricane at Wind¬ 
sor Forest, and which, upon being split, was found to be carved in the interior^ 
with the letters “ W. B. 1670.” This singular circumstance was ascribed to the 
growth of a new layer of alburnum in the part where the old wood had been cut 
out, which was subsequently formed into wood. The Chairman exhibited the 
leaves and flowers of a new species of Tamarisk, collected by Lieutenant Well- 
STED in Mount Sinai. The Secretary read a communication from Lieutenant 
W. on the Manna, Dragon's-blood, and Socotrine Aloe of Commerce. The author 
found the true Manna tree, Tamariscus mannifera., growing plentifully in 
Egypt, Nubia, and Mount Sinai, but only yielding manna in the latter locality; 
from which circumstance, as well as from its being produced by various vegetables, 
as several species of Oak, Fraxinus., and the shrub Gavan, he concludes that it is 
not a vegetable educt, but the deposition of an insect of the genus Coccus. It is 
collected by the natives early in the morning, and about 700 lb. weight is gene¬ 
rally procured during one season. The tree which yields the Dragon’s-blood 
(Sanguis draconis) grows on limestone rocks to the height of eighteen feet, and 
