204 Lord Rayleigh. On the Densities of Carbonic 



VII. " On the Ref inactivities of Air, Oxygen, Nitrogen, Argon, 

 Hydrogen, and. Helium." By Professor William Ramsay, 

 Ph.D., LL.D., Sc.D., F.R.S., and Morris W. Travers, B.Sc. 



" On the Densities of Carbonic Oxide, Carbonic Anhydride, and 

 Nitrons Oxide," By Lord Rayleigh, F.R.S. Received 

 October 12 —Read December 9, 1897. 



The observations here recorded were carried out by the method 

 and with the apparatus described in a former paper,* to which 

 reference must be made for details. It must suffice to say that the 

 globe containing the gas to be weighed was filled at 0° 0., and to a 

 pressure determined by a manometric gauge. This pressure, nearly 

 atmospheric, is slightly variable with temperature on account of 

 the expansion of the mercury and iron involved. The actually 

 observed weights are corrected so as to correspond with a tempera- 

 ture of 15° 0. of the gauge, as well as for the errors in the platinum 

 and brass weights employed. In the present, as well as in the 

 former, experiments I have been ably assisted by Mr. George 

 Gordon. 



Carbonic Oxide. 



This gas was prepared by three methods. In the first method a 

 flask, sealed to the rest of the apparatus, was charged with 80 grams 

 recrystallised ferrocyanide of potassium and 360 c.c. strong sulphuric 

 acid. The generation of gas could be started by the application of 

 heat, and with care ib could be checked and finally stopped by the 

 removal of the flame with subsequent application, if necessary, of 

 wet cotton wool to the exterior of the flask. In this way one charge 

 could be utilised with great advantage for several fillings. On 

 leaving the flask the gas was passed through a bubbler centaining 

 potash solution (convenient as allowing the rate of production to be 

 more easily estimated) and thence through tubes charged with frag- 

 ments of potash and phosphoric anhydride, all connected by sealing. 

 When possible, the weight of the globe full was compared with the 

 mean of the preceding and following weights empty. Four experi- 

 ments were made with results agreeing to within a few tenths of a 

 milligram. 



In the second set of experiments the flask was charged with 

 100 grams of oxalic acid and 500 c.c. strong sulphuric acid. To 

 absorb the large quantity of C0 2 simultaneously evolved a plentiful 



* " On the Densities of the Principal Grases," ' Boy. Soc. Proc.,' vol. 53, p. 134, 

 1893. 



