298 British Association for the Advancement of Science. 



investigations are, that this substance is not a homogeneous salt, a 

 true sesquicarbonate, as Mr. Philhps 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. Experi- 

 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 Arendahl in Norway, and the other 

 from an unknown locality. 



Mr. Thomas Exley read a paper on the specific 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, Ars. = 5.2777, Ph. =2.2222. Mr. E. conclu- 

 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 239° ; 100 parts of water dissolve 108 parts of it. 

 Boiling water dissolves 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. = 38.09' 



Hydrogen, 7.07, or 13 " = 1.625 = 6.88 

 Oxygen, 55.70, or 13 " = 13. = 55.03 



100.00 23.625 100.00 



