a88 GiifroUs Oxyd of Carhon* 



of in tl>e prefent cafe; and therefore Mr. Cruickfliank iiifcrSy^ 

 with juliice, that the other^Mnull have been originally com- 

 bined with the gas, confiitiiting it a gafeousoxyd; and hence 

 it appears that this gas bears the fame relation to carbonic 

 acid, that nitrous gas does to the nitrous acid. 

 • This gafeous oxyd feems to owe its orrgin to a dccompofi- 

 tion of carbonic add at a high temperature ; for it may be 

 obtained from a mixture of iron filings and carbonat of lime 

 in (lead of gray oxyd and charcoal, and in more abundance* 

 Twenty parts of the gas fo obtained, freed from carbonic acid,, 

 mixed with eight parts of oxygen, and fired 6ver mercury by 

 the eleftric fpark, the whole was reduced to i8 or 19 parts, 

 which were found to be carbonic acid, being totally abforbed 

 by lime water ; it contains neither water nor the bafis of 

 water : that obtained by means of charcoal yields waler, ow- 

 ing to the hydrogen which enters more or lefs into the com- 

 polition of all common charcoal. 



None of the known hydrocarbonats are frmilar in their 

 properties to the gafeous oxyds of carbon, being much lighter 

 and yielding a far lefs proportion of carbonic acid when corn- 

 biped with oxygen. They conlift of carbonic acid united 

 U'ith or held in iblution by hydrogen ; but the gafeous 6x^ d:i 

 are nothinc; but carbon united with or held in folution bv 

 oxygen, and rendered gafeous by caloric. In their produ<Slion 

 from a metallic oxyd the metal is fotmd revived, its oxygen 

 having gone into the compofition of the gafeous oxyd and 

 acid; and from their pTodu£lion by the decompofition of the 

 fame acid, (as when chalk and iron filings are employed) it 

 would appear that carbonic acid, when at a high tempera- 

 ture, may be decompofcd by any fixed fubftanee which has 

 a ftrong affinity for oxygen. I'hus the objetkions to the new 

 fyfteni of chemiftrv advanced on this head by Dr. Pricllley 

 fcem to have been fnfficiently anfwered by Mr. Cruickfliank f 

 and the prefence of hydrogen or water feems by no means ne- 

 ceflfary to the production of thefe gafeous oxyd s *. 



'■'^ Thofe who wifli to perufe a full ncconnt of Mr. Cruickfhank's in- 

 rerefting experiments on this fubjc6l, arc referred to iVIr. Nicholllm'siiJ 

 Journ^, Vol. V. April iSoi. 



