8S 



DENSITIES OF OXYGEN AND HYDROOEN 



or ;uljuste<l. Then a current was passed loiii; iMi(>Ui,di to expel any air wliic-h miglit 

 liavc entered, wlien it was attain closed and weighed foi' the next experiment. 



10. HEXSITY <)K ELECTROIA'TIC GAS. EtJDIOMKTUIC ANALYSIS. 



In the earlier experiments, a Toepler pump was connected to the globes as 

 .shown in Fii;. 32. At a is the inclined tnlte leadinij to the crlobes, seen in its con- 

 nectioii with them in Fig. 28, page 77. The U tube filled with mciciiiv to >hut 

 off the pnm[) is also shown. To this was coimected the tube <•, leading to the 



Toe[>ler pump J. While the pressure 

 of the <o-is in the <flobes w.is measiirinir, 

 the tubes leading to the pum[i were filled 

 with mercury to the plug, and the mercury 

 in e rose thirty inches or more. After 

 tile pressure had been determined, the mer- 

 cury was lc>wered till the bottom of the 

 tube (■ was uncovered. Gas from the globes 



U|;:| 1/ I II el ^^'^'" P-'i^^t'd through the tube to the 



I I I 111 '' I Toepler pump, driving over the mercury 



'' I I ' It M '" ^''*' '^"^^^ '■' '^"*^ without doing damage. 



The [)unip body ha\ ing been filled with 

 ga.s, the volnnie withdrawn was determined 

 3 by a second I'eading of the [)ressurt' of 

 the remaining gas. 'J'hc mercury in the 

 pump was then raised so as to separate 

 this fraction from that left in the globes. 



A Bunsen eudiometer was filled with 

 mereviry and set at m, Fig. 32. A small 

 Toejder pump, having a capacity of, say, twenty cubic centimetres, had been con- 

 nected as shown at A, and was provided with a trap against the entrance of air 

 with the meicnry which actuated it. With this, the gas was transferred in suit- 

 able volumes to the eudiometer and ex])loded. Four explosions a minute was the 

 usual working rate, so that the 1.(3 litres which the pumj) held were exploded in 

 forty or fifty minutes. 



Krr., 32. — Toepler pump used to measure s.imple 

 for .Tiialysis ; small Toepler pump for trans- 

 ferrini; convenient quantity to eudiometer. 



11. — DK.N.snV OI' KLKCTUOI.VTIC OAS. Ill I- 1- ICII.rV ol' IMIKV K.N II N(. KMI.'ANCK OK All! 



INTO TIIK i;i;i»IOMlTKi;. 



The eudiometer stood in meicnry to the de]itli of about ten centimetres, but .-it 

 first nitrogen was always found in the residue after explo.sion. Increa.seil larc did 



