298 British Association for the Advancement of Science. 
investigations: are, that this substance is not a homogeneous salt, a 
true sesquicarbonate, as Mr. Phillips considered it, but a mechan- 
ical mixture of carbonate and bicarbonate. Mr. S. also read a 
paper on the blackening of Nitrate of Silver by Light. Esxperi- 
ments which he has made result in the conclusion previously as- 
serted by Dr. J. Davy and by-Mr. Fergusson, (although contra- 
_dictory to the statements of most books of chemistry, ) that pure 
nitrate of silver, is not blackened by continued exposure to sun- 
light, unless organic matter is present. 
Mr. Thomas Richardson ‘presented an examination of two spe- 
-cimens of Sphene, one from. 2 niagara in 2p and the other 
from an unknown locality. 
Mr. Thomas Exley read a paper on the apsnifc gravities of Ni- 
trogen, Oxygen and Chlorine, and of the Vapors of. Carbon, 
Sulphur, Arsenic and Phosphorus. By experiment and calcula- 
tion, he finds the following to be the true gravities of these sub- 
stances, viz. N.=.9722, O.=1.1111, H.=.0694, Chl. =2.5, C.= 
.8333, S. = 2.2222, ee ‘= 5.2777, Ph. 2.2222, Mr. E. conelu- 
ded by suggesting an opinion that there is another elementary 
_. body, yet undiscovered, having both an exceedingly small sphere 
of repulsion, and an exceedingly small atomic weight, or abso- 
lute force. This substance, he conceives, gives rise to the mi- 
asmata ‘of marshes, to infectious effluvia and other. concomitant 
exhalations ; chlorine, acids and other substances, owe their dis- 
infecting qualities to their power of absorbing this substance into 
their atmospheres. If its existence should be ascertained, Mi- 
crogen might be deemed an appropriate name. 
Dr. T. Thomson read a paper on Diabetic Sugar. This sugar 
has been commonly considered as isomeric with starch sugar. 
Taste, sweet ; color, snow-white ; gravity, after fusion 1.56 at 
65°: melts at 2399 100 parts of water dissolve 108 parts of it. 
Boiling water Lannion: any quantity. Soluble in alcohol. -It 
crystallizes, but so irregularly that the shape of the crystals has 
not been ascertained. After being dried in vacuo over sulphuric 
acid, it loses an additional atom of water if it be exposed to a 
heat of 212°, without losing weight» Analysis of it gave, 
_ Carbon, 37.23, or 12 atoms = 9.. se 38.09; 
Hydrogen, 7.07, or 13 “, = 1.625 = 6.88 
Oxygen, 55.70, or 13 is eee bBo + = BROS - 
100.00 - ~~ 93.695 100.00 
