( 504 ) 



The jet of lirpiefied ans lei in at a (plate I) is directed, hy means 

 of llie cock //,. and tlie liltci- /, a.uainsl a ,<;hiss wail fi'oin wliicli it 

 streams aloii.i;' llie dclixcry spoilt 1)^ into the l)alli, here a (h»id>h:! 

 beaker li,, />„, (Pis. 1 and 11). placed in the i)eak("rs />\, /A^, />'., of 

 PI. 1 ('oium. 51. 'i'h(> cock and tiller form part of a co\('i' wincli as 

 descrilx'd in ('onim. 51, may he remoxed togeliier willi ,\ and X, from 

 llie crvoslal and may also he rc|)laced hy a syphon or a caj)illai-v with 

 a cock onlside the ciyoslal. The spi-eadin.ü: of the jet ox'er the 

 wall mav he watched thronuh the windows Tj, and the height of 

 the li(pnd ill the hath thi-oni-h the windows T,. 'J'he liltcr /' serx'es 

 |)i-incipally to prevent (tpatpie dnsi from the lead (oxide of copper etc.) 

 from dcposilinii- jnst at the place whej-c the jet tonches (he glass. In 

 main cases, however, it hap|)ene(l in spite of the care taken in piu'ili- 

 catioii. that the li(pielied gas itself, while evaporating nnder i-ednced 

 pressure in the cryoslat, had deposited a snhstance, formerly dissolved 

 ill i( |)iii solid at the lower t(Mnperatiire, thus rendering the hath 

 opa(pie. 'i'herefore, dillering from Comin. 51, a glass beaker T^ (Pis. 

 1 and 11) with nnmerons openings in the bottom 6'i„ (PI. 1 1) and con- 

 taining some glass wool was suspended by the regenci-ator spiral A 

 (PI. 1 C'omin. 5J). This lilter may be lifted from the cryoslat together 

 with the ]>iece ;S,.. 



With th(^ arrangement as described in ('omin. 51 all the gas, formed 

 after the licpiid leaves the coek, goes in the direction indicated by 

 the arrows on PI. 1 ('oiiiin. 51. With the arrangement as described 

 here, however, the gas which is formed while the bath is being tilled 

 folhtws in the main a dilfeirnt direction to that which afterwards 

 evaporates from the bath. In fact, ditlering from ('oiiim. 51, a valve 

 /; with a spring />,., has been added, which almost (doses the o[)ening 

 of \\\o delivery s|)oiil JJ^ h)r gas, but allows li(piid to How through 

 a verv narrow opening 1),^, aloJig the gutter />,.,. The first consi- 

 derable (piantities llowing from the cock, serve to cool all the beakers 

 and the whole cryoslat in the way indicated in ( oniin. 51 (the arrows 

 of |»late 1 might be borrowed from |)lale I of (Nmim. 51), unless the 

 supply becomes so great that the valve D^^^ is opened and the gas 

 also Hows out through the opening /t,„ in the ring A'^, i)lale II. 

 The gas which later evai)oratcs from the beaker A',,^, linds the valve 

 D^^^ closed and escapes only through the oi)ening /^„, along the way 

 indicated by Ihe arrows on |.»late 11, so that it serves only to screen 

 the inunediate neighl)ourhood of Ihe bath from external heat. 



The ditference in form between the rings h\ and //, oji plate 11 

 and tli(»se on plate 1 (\)niin. 51 is very slight. This follows from the 

 wish to use the ])arts that served in the experimenls, refei-red to in 



