346 C. Barus — Effect of Temperature, etc. 



nuclei. The degree of ionization is here independent of the 

 sign of the charge. 



If the phosphorus grid is not preliminarily quite dry, traces 

 of moisture are apt to escape with the emanation and produce 

 permanent conduction in the condenser. Considerable varia- 

 tion of the electrical coefficients may thus ensue, though the 

 color results are, relatively speaking, but slightly affected. As 

 the electrical discrepancy seems to be out of proportion with 

 the quantity of moisture present, it is probable that the ema- 

 nation escapes in some combination with it. The whole 

 phenomenon vanishes on thorough desiccation both of the 

 phosphorus and the apparatus. Grids frequently treated in 

 this way show a gradually decreasing ionizing intensity, prob- 

 ably due to the continued consumption of phosphorus or to a 

 removal of effective surface. Throughout the experiments the 

 relation of the color curves to the electrical curves remains 

 practically unchanged, in spite of the different degrees of satu- 

 ration (ionization). 



The relatively enormous conductions associated with non- 

 desiccated phosphorus are without a color effect when tried in 

 the steam tube. They rather give evidence of an abstraction 

 of nuclei. Moreover such reciprocal properties are manifest in 

 other instances. § 18. Air passed over damp paper behaves 

 similarly to the emanation from non -desiccated phosphorus, 

 with a difference of intensity in favor of the latter. Desicca- 

 tion over calcic chloride removes the incidental conduction 

 entirely. The emanation may thus be dried to a limiting 

 degree of ionization which is not then further reduced on dry- 

 ing. In practice all operations should be made with desiccated 

 phosphorus ; otherwise the baffling discrepancies encountered 

 in the case of plate and spherical condensers may be antici- 

 pated. 



By using freshly cut fuming phosphorus in excess in the 

 ionizer, it was possible to increase the radial currents in the 

 condenser to nearly twice their usual value, remembering that 

 the emanation within the condenser is in all parts essentially 

 unsaturated. Hence the low concentrations formerly found 

 for tubular condensers (2X10 4 nuclei per cubic centimeter) is 

 made to approach the value found from plate and spherical 

 condensers (4X10 4 ), more nearly. 



Brown University, Providence, E.I. 



