20 



THE STRUCTURE OF THE NUCLEUS. 



dei>euik'iu-f uf the emanation itself on temperature. This could be done by 

 surround ing the condenser with a steam jacket (shown in figure 2,^, *•, s, being the 

 iiitinx and efflnx pi[tes) and noting the effect of the rise of temperature of nearly 

 100°. After repeated trials, however, I found that the high temperature so far 

 diminished the insulation of the hard rubber l»ushings of the condense!', that 

 no measurements would be trustworthy. On cooling the condenser, the insulation 

 again became perfect. Quartz iusulatois suggest themselves as probably alone 

 avaihible. 



23. Comparison of old and new grids. — Trial was made with freshly cut 

 phospliorus, the grids used in the above work being as much as a year old. The 

 results show a like order of values for l)oth, in spite of the intense fuming of the 

 new grids. Nevertheless, the latter is apt to be from 2 to 3 times sti'ouger thaa 

 the ohl <rrid. Thus after thoi-oughly drying the new grid over calcic chloride and 

 testiiifj it at 21.5° the data were : 



dV/iit = .42, (,u'i/V/)oAo = -2°. 



■43. — -^o- 



Exposure to the air of the room for about half an hour after desiccation was without 

 effect. 



The question as to the maximum number of nuclei producible by [diosphorus, 

 thoroughlv <lried over calcic chloride, under favorable conditions, was deemed 

 sufficiently important to justify the additional experiments detailed in table 11. 

 The data are oljtaiiied from an entirely new adjustment of apparatus, including the 

 electrometer; but they are nevertheless a corroboration t>f what has just been 

 stated. The attempt ti> prolong these experiments indefinitely was cut short by 

 spontaneous ignition. 



This experiment proves that the air in all the eai-lier experiments was under- 

 satui'ated, agreeing with an earlier paper from ^\ hich values are quoted in the next 

 paragi'ajth. 



T.\BLE II.— BEH.WIOR OF FRESH DRY PHO.SPHORUS IN EXCESS. E„ = 41 

 VOLTS, e = 2o^ INSUI..\TION PERFECT. DESICCATED 20'" OVER 



C.\CL.,. 



later. P in |)lace. 



755 



44 



44 



•5° 

 148 



20 

 20 



SiiontaiiLOus ignition on removing from water liath. 



