THE STRUCrUHE OK THE NUCLEUS. 



of about 2 [ler ceut. [wv fall of 1 C. Tli-' niaximum activity occurs at about 13°, 

 and is iipwarils of 25 per cent, greater than at 30". Between 12" and 13^ however, 

 the emanation is (juencheil at an enormously rapid rate, falling just sliort of sudden- 

 ness. Practically, therefore, the reaction begins at about 13', with full if not 

 greatest intensity. 



Helow 12-, the emanation is insignificant an<l the ma.xinuim permanent colors 

 obtainable are faint blue grays, even when the gasometer flow is forced to, say, 400 



JiO 



dY/di 



/5_ 



o \. 



10 





5 



dt/dV 



FUj.4. 



JO 



W 



■V) 



40 



Fiy.S. 







'-^ 



^ 



=>^ 



I 



X 



■30 



■36 



10 J', M) -'•' 



Fig. 3. — UEi'h.NUKNCE oi- THE KecU'Rocai. Nl'Ci.kaho.n Kaie \i(t idi) O.N Temperaukk. 1-10.4. — IJEI'END- 



F.NCE OF THE Ni.cLEATio.N Rate (aV/i/F) O.N Temperature. Fig. 5.— Co.mparison of the Rates of Electrical 

 Discharge and of Volume Efflux. 



liters/minute. There are no opaques. Below 10° there are no [lermanent colors 

 discernible. 



5. Here, however, and slightly above and below this temperature, definite 

 puffs of color or of darkness are obtained immediately after oi)ening the faucet 

 suddeidv. Tiie [thenomenoii may be repeated indefinitely by closing the faucet for 

 a period of 2-5 seconds (longer at the lower temperature), and then suddenly 

 opening it again. The puffs are at fii'st vaguely recognized at about 8°, or even 

 below. They become more marked as temperature rises. They are still markeil at 

 even 12", when the fainter colors are beginning to be permanent. They show a 

 ma.ximum degree of darkness depending on temperature, beyond which they ilo not 

 inciea.se even if the cock is closed indefinitely. 



From a theoretical point of view this result is noteworthy. Below the reaction 

 temperature (say 12.5"), what may be called the va[)or prcssme of the reaction is 

 a definite quantity, but decreases with temperature at an enormously rapid rate; 



