UKNSITIKS Ul-' OXYUEN AM) IIVDKOCEN 



uitli iislit'sids, i<> pirveiit loss of fusible metal \>\ ]ii'(>jectinii wlieii ineltetl. / is a 

 giomiil joint by uliit-li tlii^ tube can be coiiiiec-tetl with otliei' apparatus. The tube 

 between </ ami the point I- is e.\liauste«l and then closed at k by fusion, and a notch 

 made between i and I: 



-%^J1 



^ 



Kh;. 2;. — I'nllailium tube with no Mo|icock. 



When tlif [);illailiiim is to l)e chai-ged with hydiogen, </ is t'uscil to tiie source uf 

 tlie ^as, and the [lalladiuui is heated. When the temperature is such tliat no absorp- 

 tion woidd take i)lace, hvdroi^fii is passcil through the tube from »/ to //, the tube 

 havin^'^ been l)n)ken oil' at lliis point. The heat is laiscd, ami tiic current 

 continued for halt" an lunir, wiicii 11 is closed by fusion, ami I he hetit withdrawn. 

 Hydrogen is admitted from an ajjparatus in which it is produced by electrolysis of 

 sidithuric acid in voltameteis, and then freed from oxygen, and compounds containing 

 o.xygen, by passing over heated coppei", potassium hydroxide, and phosphorus 

 pentoxide. When the pressure of the gas in the palladium tube becomes equal to 

 that of the atnios[)here, the point a is again Iji'oken olf, and the current continued 

 for three or four hours ; during pait of this lime, the gas is allowed to escape at f. 

 Bv this long-continued jiassage of the gas escaping at ii and /', it was lioped to 

 remove very nearly all the nitrogen whicli. if once present in the gas, woidil not 

 be renioveil bv the purifying train. Since the tension of the gas in the palladium, 

 cspecialiv when it is satiir.ite<l, is considerable, the icnioval of the nihdgen with 

 the ail-punip cannot i)e effected. 



When the charging with hydrogen is completed, the ends (f and f are closed 

 bv fusion, and the connection with the source of hydrogen at */ is closed in the 

 same way, when the palladium is ready for weighing. 



17. — MVI>KO(iKX ItV M;\V MKIUoK. II VI'i;osr.\TR' WlvK.IIINo o|- TIHK (ONTAINIXfi 



I'AI.I.ADirM. 



\N'lieii tlif tube was charged with hydrogen, and closed by fusion, its \..lnnie 

 was determined by hydrostatic weighing in a way which calls f(U- no remark. The 

 tube expo.sed nothing to the water but a continuous surface of glass. It was there- 

 fore not likely to suffer much change of weight by immersion. The tube was of 

 the common German glass; it would now be possible to construct it of one of the 

 new soits of (_d,iss whieh nsist the action of water in a much greater degree. But 



