(289 ) 



l<'is. T. 



Even small quantities of liydrogon, added to the carbonic acid 

 cause a great increase ut' pressure when the latter gas is condensed. 

 In order that the end of the condensation can be reached without 

 danger to the glass tube, the experiments were made with a mixture 

 containing 5 mol. h3'drogen on 100 mol. 



The volumes of the mixture were measured in a m.anometer-tube 

 of about 0,05 c.m.^ in section, on which a graduated scale in m.m. 

 had been etched tested carefully by a kathetometer. The calibration 

 Avas made by filling the tube with mercury and by causing this 

 liquid to flow out in small quantities; the columns of mercury thus 



