THE STRUCTURE Of THE NUCLEUS. 



that thf exlrcim- caution ii.td..l lu-foie siuli a i>ropeity can be iiredicated becomes 

 ap[>areiit. 



VOLU.MKTItK ( O.MI'ARISONS. 



2. Ajmanitui^. — The aiii)aratu.s to investigate tlie relation <>1 tht- emanating 

 activity of phosphorus to temperature is shown in figure 1, the thermal part con- 

 sisting of a coil of thin lead j.ipe (1/8 inch bore), X, submerged in a large water 



l);ith of c()p]ier, AB, 13 centims. high, 

 15 centims. broad, and 20 centims. long. 

 t There were 21 turns of lead pipe, each 



turn 6 centims. in diameter. The air 

 coming from the gasometer train by 

 ^ way of a desiccator beyond B, and a 



Jj stop-cock, F (fine screw valve), tra- 

 versed this considerable length of slen- 

 der tubing, fully taking the temi)erature 

 of the water bath, thereafter to be dis- 

 chai'ged into the central straight pipe 

 of brass, ab, 1.2 centims. in diameter, 

 containing the ionizers (not shown). 

 The charged air is finally conveyed into 

 the influx pipe of the color tube, O, by 

 the removable short neck, G. A ther- 

 '</ mometer, t, is placed in the water bath ; 

 another may be inserted into the end, 

 h, thi-ough a perforated cork, soas to be 

 in contact with the ionizers. 



Care was taken that all changes of 

 temperature should be slow. Thus it 

 took 3 liours foi' the temperature to rise 

 from 5^ to 1.") ill the following experiments, for instance. 



The ionizers, as usual, were strips of wire gauze, holding thin pellets of 

 phos[>horus between them. They were inserted into, or removed from tlie tul)e, <//-, 

 through h. If saturation is aimed at. an excess of freshly cut phosphorus surface 

 .should l)e used. This was only done when specially called for in the present woik, 

 where the form of the temperature function is the chief consideration. 



3. Method and data. — The method of experiment usual in my work wa-s 

 adopted, the liters per minute (dV/di) of saturated phosphorous air necessary to 

 produce the fiducial blue of the color tube being observed at different temperatures. 

 The data are triven in table 1. in tlie first part of which observations for falliiiir 

 temperature, and in the second for rising temperature, are recoi'ded. The pressure 

 of the steam jet was about ^>=: 4 to 6 ceiitim.s. The inflowing air showed a temper- 

 ature of 27° to 28°. The table contains some other colors (including opaque) for 

 orientation. 



(• 



A' 



^m 



.J 



Kli;. 1.— Al'I'ARAl'US FOR IlKAl'lNO NUCLEATKI) .\1K. 

 KlO. 2.— SkOTION of the TlMlUI.AR CoNDEXSKR SlIOWINC. 

 IIIK Vai-'jk Iacket. 



