AND RATIO OF THEIR ATOMIC WEIOMTS. 101 



off while it was enclosed in a tube wliicli delivered dry air. The grouud joints 

 Avliieli fitted e, c, I'oiined the ends of two drying tubes filled with phosphorus pent- 

 oxide. One of these tubes was now [)ut on c. Tiie other jioint e was broken 

 off and the other diying tube also put in [)lace ; both Joints were of course made 

 tight with paraffin. The object of these tubes was, to prevent the admission to 

 the weighed tube of any moisture produced in the glass-blowing operations required 

 in putting the apparatus together. It is now seen that the manipulation might 

 have been made simple)' ; but not more accurate. 



The combustion a])paratus with the addition of the phosphorus pentoxide 

 tubes was now [ilaced in the condenser h, h, Fig. 37. This consisted of a cylindei- 

 of dass, havinir a bi-ass bottom with two tubulatures; into one of them the com- 

 bustion apparatus was placed, and made tight with a rubber tube. 



7, SYNTHESIS OF WATER. "MANIPULATOR FOR REGULATING THE PROGRESS OF TIIE 



COMBUSTION. 



The condenser with its contents is next placed in the manipidator shown in 

 Fig. 37. At i and h are the tubes by which oxygen and hydrogen are to be in- 

 troduced ; I leads to the Toepler air pump. The stopcocks m and n serve to con- 

 trol the admission of the gases into the combustion chamber. The tubes o imdj>, 

 which are connected directly to the tubes / and I; show the pressure of the oxygen 

 and hydrogen at tlieir sources. The tube g, interposed between the stopcock m and 

 the combustion chamber, shows the pressure of the gas therein. The ends ;■ and s 

 are now fused to the somewhat flexible connections t and u. As said before, the 

 drying tubes x and y pi'event the entrance into the weighed drying tubes of the 

 water formed in this pi'ocess. 



The globes containing oxygen are uaw fitted into the corresponding ground 

 joints, and these are fused to the branches leading from the tube i, as shown in 

 Fig. 38. The point of the palladium tube is broken oft" and a joint is fitted on and 

 connected by fusion to the tube ?<;. 



The five stopcocks m, n, 1, 2, 3, being open, the apparatus is exhausted to one 

 part in ten thousand, and the pump is shut off by ^closing the stopcock £. The 

 stopcock 3 is opened, when mercuiy fills the tubes 4, 5, closing all connection 

 between the hydrogeu and the oxygen sides of the apparatus. The stopcocks 1 and 3 

 ai-e now closed, preventing disturbance of the level of the mercury in these tubes. 

 The stopcocks m and n ai-e next closed, and the stopcock of one of the globes of 

 oxygen is opened, when the gauge o shows the pressure of the oxygen in it ; the 

 other globe is also opened. The fusible metal plug is then fused, when the gauge 

 p shows the pressure of the hydrogeu from the palladium. 



