Analysis of a Mangamsian Garnet, 155 



that pure oxygen was liberated ; and if it took the oxygen, 

 or a part of it, from the deutoxyde, already generated by 

 the union of carbon and oxygen in the formation of carbonic 

 acid, thereby leaving a compound of azote and oxygen in 

 the state of nitrous gas — it must have reduced it to the 

 protoxyde, or gazeous oxyde of azote, its first degree of 

 oxydizement. 



It is known that charcoal, especially when newly made, 

 has the property of absorbing sundry gases, and particular- 

 ly hydrogen. Might not the charcoal I used have contain- 

 ed hydrogen ? If so, might not the nascent hydrogen during 

 the action of the carbon, have combined with a part of the 

 oxygen of the nitric acid, and formed water ; whilst that 

 portion of the azote thus set at liberty, by combining with 

 the carbon, may have formed the carburet of azote ? 



The existence of cyanogene, however, is indisputable, in 

 whatever manner it may have originated. One atom of 

 azote and two atoms of oxygen form the deutoxyde of azote, 

 and two atoms of carbon with one atom of azote form cy- 

 anogene. I have not had leisure to repeat the experiment, 

 in order to determine the quantity of cyanogene thus gene- 

 rated. 



Art. IX — Analysis of a Manganesian Garnet, from Had- 

 dam, Connecticut, with a notice of Boric Acid in Tourma- 

 lines ^ i^ Henry Seybert. 



This mineral occurs imbedded in granite, associated 

 with Cymophane and Beryl. In mass it is blood red; the 

 powder is flesh coloured. Lustre, resinous. Small frag- 

 ments are transparent. The specimen made use of for 

 analysis was a portion of a large crystal. Fragments, inde- 

 terminate. Scratches glass and scintillates with steel. 

 Very frangible. Structure lamellar. Specific gravity 4.128. 

 Fusible, before the blowpipe, into an opake black bead. 



Analysis. 



s 



A. 3 grammes of this garnet, in the state of an impalpa- 

 ble powder, were exposed to a red heat in a platina cru- 

 cible ; after the calcination, the colour of the powder was 

 not sensibly altered, and it weighed 2.98 grammes, there- 



