Emanations of Phosphorus through Air and other Media. 397 



Table III. gives the distance apart, x, of the condenser- 

 plates, the current time (date), and the constant c' is computed 

 from V = V 10 — c '*, for the time, t, given in minutes. The 

 values of V and t themselves are suppressed for brevity. 



Table III. 



Transmission of the Phosphorus Emanation in Air. Summary. 



c / = cloge=-(^V/^)/Vln 10. 



Distance 

 apart, x. 



Mean Time. 



c' computed 

 directly. 



c", cotempo- 



raneous * 



values for 



a?=l'7. 



c', corrected. 



cm. 

 17 



h m 

 11 18 



•200 





200 



•200 



5-7 



22 



•023 





196 



•024 



25 



32 



•120 





187 



•128 



Ho 



43 



•002 





178 



•002 



1-8 



12 3 



•130 





160 



•162 



37 



14 



•033 





150 



•044 



17 



25 



•140 



•140 



•200 



* Time correction made linearly. At a?=l"7 cm., the value of c' fell from 

 •20 to *14 in 67 minutes, i. e., "0C0y per minute. This result is referred to 

 above in relation to Table I., § 4. 



It will be noticed, however, that the value of c' at #=1"7 

 centim. has fallen off considerably during the course of the 

 experiment. Its probable value at the successive times and 

 a?=l*7 is given under c". For any values of x, the observed 

 value, c', is to be referred to the value c" (x = l'l centim.), 

 corrected for the apparent decreased intensity of the phos- 

 phoric ionization above referred to. 



8. It will be seen in my next paper that the current 

 removes a relatively insignificant number of particles. Hence 

 in the condenser (fig. 2) tbe loss of ions is due either to their 

 mutual destruction or decay in the space x between the plates, 

 or to their escape laterally out of this space into the sur- 

 rounding atmosphere. 



Let n be the number of particles per cubic centim. at a 

 distance x from the phosphorus grid P (fig. 2). Let A be 

 the area of the condenser of air-space x, and let ax be the 

 circumferential area terminating in the edges of the condenser 

 (mantel of the cylinder of air). Let k be the (absorption) 

 velocity of the ions in the absence of an electric field, when 

 passing from a nearly saturated region either into free air, 



