30 



FXVI tMMKNTS WITH IONIZED AIR. 



directly into the open end of the tube, which is telescoped (not shown) so that the 

 lowei" section may be I'aised to facilitate access to the Jet. The mirror for 

 illumination is at m, n being the observation window cleared through a, and e the 

 escape steam pipe. 



The bottom of the spindle is joined by a thin tube, /, called absorption tube, 

 about 1 millimeter in diameter to the phosphorus ionizer, P, which here consists of a 

 tube about 30 cm. long and 1 cm. in diameter, charged in the manner described 

 above, i^is the screw stop-cock, D the desiccator, U the pressure gauge, (' the 

 volume flask, M the large Mariotte flask. 



Figure 9 is a slender tubular condenser by which the absorption tube t may 

 be re[)laced for correlative electrical raeasui-ements. See Chapter 5. 



11. liesults. — In table 7, I have given several series of results obtained 

 at different times. Different absorption tubes at t were u.sed, and hence the 

 i-esults can only be compared by putting the volume of charged air producing 

 the standard blue equal to one unit. Variations betweeu the series necessarily 

 remain, because it is impossible to select the same shade of blue from a continuous 

 series. The pressure of the steam Jet is given under/*; 8 is the air temperature, 

 and dP the pressure excess in the volume flask in cm. of mercuiy. Reduction to 

 standard pressure and temperature is superfluous. 



TABLE 7.— COLOR AND RELATIVE NUMBER OF PARTICLES IN CASE OF NEW 



JET (AXIAL INFLUX). "BLUE"= i. 



These observations are constructed in the chart figure 10, by representing as 

 abscissas the thicknesses of air-plates which would give the same color by New- 

 ton's interferences for normal incidence and transmitted light, as no better method 

 is immediately available. The ordiuates are the volumes per minute of charged air 

 producing the .same color in the tube. The curves are taken directly from the 

 chart, figure 3. 



