of carbonic Oxide and Chlorine. 447 



idea, since I have found that bright sunshine is not essen- 

 tial, and that the combination is produced in less than 

 twelve hours by the indirect solar rays, light alone being 

 necessary. 



The formation of the new' gas may be very readily wit- 

 nessed, bv niakiuff a mixture of dry carbonic oxide and chlo- 

 rine in a glass tube over mercury : if light be excluded, the 

 chlorine will be absorbed by the mercury, the carbonic oxide 

 alone remaining ; but if bright sunshine be immediately ad- 

 mitted when tlie mixture first is made, a rapid ascension of 

 the mercury will take place, and in less than a minute the 

 colour of the chlorine will be destroyed, and in about ten 

 minutes the condensation will have ceased, and the com- 

 bination of the two gasses will be complete. 



It is requisite that the gasses should be dried for forming 

 this compound ; if this precaution is neglected, the new 

 gas will be far from pure ; it will contain a considerable 

 admixture of the carbonic and muriatic acid gasses, which 

 are produced in consequence of the decomposition of hy- 

 grouielrical water. Indeed there is considerable difficulty in 

 procuring the new gas tolerably pure ; a good air pump is 

 required, and perfectly tight stopcocks, and dry gasses, and 

 dry vessels. 



I have endeavoured to procure the gas, by passing a mix- 

 ture of carbonic oxide and chlorme through an earthenware 

 tube healed to redness ; but without success. 



The specific gravity of the gas may be inferred from the 

 specific gravities of its constituent parts jointly with the 

 condensation that takes place at their union. According to 

 Cruickshaiik, 100 cubic inches of carbonic oxide weigh 

 -29'6 grains, and acc-jrding to Sir Humphry Davy, 100 of 

 chlorine are equal to 76-37 grains : d ence, as equal volumes 

 of these gasses combine, and become so condensed as to 

 occupy onlv half the space they before filled, it follows that 

 100 cubic inches of the new compound gas are equal to 

 105-97 orains. Thus this gas exceeds most others as much 

 in its densilv as it does in its saturatmg power. 



To ascertain whether chlorine has a stronger affinity for 

 hydrogen than for carbonic oxide, I exposed a mixture of 

 the fhree gasses in equal volumes to light. Both the new 

 compound and muriatic acid gas were formed, and the affi- 

 nities werebo nicely balanced, that the chlorine was nearly 

 equally divided between them. And that the attraction of 

 chlorine for both these gasses is nearly the same, appears to 

 be confirmed by muriatic acid not being decomposed by car- 

 bonic oxide, or the new gas by hvdrogen. 



F f 4 ' The 



