COMPOUNDS OF CARBON WITH OXYGEN AND NITROGEN 403 



phuric acid, because the latter assists the decomposition by taking up 

 the water. On heating a mixture of oxalic and sulphuric acids a 

 mixture of carbonic oxide and carbonic anhydride is evolved. This 

 mixture is passed through a solution of an alkali in order to absorb 

 the carbonic anhydride, whilst the carbonic oxide passes on. 28 bij 



In its physical properties carbonic oxide resembles nitrogen ; this 

 is explained by the equality of their molecular weights. The absence 

 of colour and smell, the low temperature of the absolute boiling point, 

 140 (nitrogen, 146), the property of solidifying at - 200 

 (nitrogen, -202), the boiling point of - 190? (nitrogen, -203), 

 and the slight solubility (Chapter I., Note 30), of carbonic oxide are 

 almost the same as in those of nitrogen. The chemical properties of 

 both gases are, however, very difierent, and in these carbonic oxide 

 resembles hydrogen. Carbonic oxide burns with a blue flame, giving 

 2 volumes of carbonic anhydride from 2 volumes of carbonic oxide, just 

 as 2 volumes of hydrogen give 2 volumes of aqueous vapour. It 

 explodes with oxygen, in the eudiometer, like hydrogen. 29 When 

 breathed it acts as a strong poison, being absorbed by the blood ; 30 

 this explains the action of charcoal fumes, the products of the 



28 bis Greshoff (1888) showed that with a solution of nitrate of silver, iodoform, CHI 3 , 

 forms CO according to the equation CHI 3 + 8 AgNO 3 + H 2 O = 8 Agl + 8HNO 3 + CO. The 

 reaction is immediate and is complete. 



29 It is remarkable that, according to the investigations of Dixon, perfectly dry 

 carbonic oxide does not explode with oxygen when a spark of low intensity is used, bui 

 an explosion takes place if there is the slightest admixture of moisture. L. Meyer, 

 however, showed that sparks of an electric discharge of considerable intensity produce 

 an explosion. N. N. Beketoff demonstrated that combustion proceeds and spreads 

 slowly unless there be perfect dryness. I think that this may be explained by the fact 

 that water with carbonic oxide gives carbonic anhydride and hydrogen, but hydrogen 

 with oxygen gives hydrogen peroxide (Chapter VII.), which with carbonic oxide forms 

 carbonic anhydride and water. The water, therefore, is renewed, and again serves the 

 same purpose. But it may be that here it is necessary to acknowledge a simple contact 

 influence. After Dixon had shown the influence of traces of moisture upon the reaction 

 CO + O, many researches were made of a similar nature. The fullest investigation into 

 the influence of moisture upon the course of many chemical reactions was made by Baker 

 in 1894. He showed that with perfect dryness, many chemical transformations (for 

 example, the formation of ozone from oxygen, the decomposition of AgO, KC1O 3 under 

 the action of heat, &c.) proceeds in exactly the same manner as in the presence of 

 moisture ; but that in many cases traces of moisture have an evident influence. We may 

 mention the following instances : (1) Dry SO 3 does not act upon dry CaO or CuO ; (2) 

 perfectly dry sal-ammoniac does not give NH 3 with dry CaO, but simply volatilises ; (8) 

 dry NO and O do not react ; (4) perfectly dry NH 3 and HC1 do not combine ; (5) perfectly 

 dry sal-ammoniac does not dissociate at 350 (Chapter VH,Note 15 bis) ; and (6) perfectly 

 dry chlorine does not act upon metals, &c. 



50 Carbonic oxide is very rapid in its action, because it is absorbed by the blood in 

 the same way as oxygen. In addition to this, the absorption spectrum of the blood 

 changes so that by the help of blood it is easy to detect the slightest traces of carbonic 

 oxide in the air. M. A. Kapoustin found that linseed oil and therefore oil paints, are 

 Capable of giving off carbonic oxide while drying (absorbing oxygen). 



