ee 
caine eens 
Phosphorescence of Sub-resizs« 189 
thirteen stars, as en by seven different observers ; and 
finds that, pri speaking, the greatest di of = 
sults have occurred in those stars whose 
frangibility, i “4 Hcg greatest and the least ; and that the differ. 
ences of results have been the least in Capella and those 
stars = ei reffangiblity is nearest to the mean.» From nu- 
merous experiments Dr. F. concludes that the refractions-of 
Capella appear to equal the mean iene see | and those of 
Lyre, and Aldeburan ae two extremes, — 
29. On the effect of animal oer in in preventn the sae 
Faction o at water.—M..A. lier, of pier hav- 
ng been consulted PY: a gentleman oo the best methed 
of preventing a pond in his garden from putrefying, recom- 
mended . a em mployment of saan cbirceet. ines experi- 
ment was tried with perfect success. The small pond vor 
basin was about 9 feet in diameter and 3 deep. Tie water 
proceeded from a spring; but towards autumn it became pu- 
trid, and exhaled a mephitic odour.. On the 10th of August, 
1823, 45lbs of. animal. charcoal in powder were thrown into 
it, care being taken to spread it enn on the rea where 
it at first floated ; but afterwards. fell to the b - The 
effect of this was to remove all oinare smell pony the wa- 
ter; and M. Chevalier upon examining a bottle of it, found 
that it had neither an offensive smell nor taste, though it had 
been-out of the pond for § days.. M. Chevalier observes 
‘that the animal charcoal which has been thus used in a pond 
might when taken out be used as a manure, as it gives out 
by slow degrees to vegetable bodies, the substances which it 
has absorbed. See the Journal de Pharmacie for 1824, p. 
73.—Dr. Brewster's Journal. 
30. On the phosphorescence of several sub- eso Bobs 
tre who has made some interesting experiments on thiscabject, 
has given the name of sub-resins, to those which are entirey 
deprived of essential oil, which are deprived of acid, and 
whielr are soluble only in boiling alcohol, ether, or the vola- 
tile oils. ‘The property of phosphorescence, when they were 
pounded ina porcelain mortar with a glass pestle, he found in 
gum Elemi, gum Alonchi, and the gum Arbol-a-brea from 
Manilla. In gam Elemi the light was pale and feeble, and 
less than is shown in pounding sugar. In gum Alonchi well- 
