94 



A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



R is a soft rubber cork which can be raised or suddenly lowered (in the latter 

 case by the blow of a swivelled hammer not shown in the figure) by actuating 

 the knob or handle at the upper end of the rigid rod r. There is a stuffing box 

 at S. The end of the tube p has been turned off smoothly and serves as a seat 

 for the plug, R. Stiff glycerin is used as a lubricant. All passageways and 

 pipes are wide, the latter at least one inch in diameter. The valve has retained 

 its efficiency after countless experiments, but it must be left open when not in use. 

 34. Results. — The results are given in table 18, on a plan similar to 

 the above tables, and the calculations are made in the same way. All 

 operations were strictly timed, and it was thought best to co.npute 5 fi^om 

 subsidence as 



S' = sl(i-'~{sU./si)). 



The corresponding n.^ is written »1. The result is 5'= 1.95. Computed from 

 the observations themselves, S=2.i, 1.7, for instance, in the first two parts of 

 the table, a difference which can only be explained on the ground of obser- 

 vational error. Ustially 3 minutes were consumed by the operations between 

 the exhaustions, while the fog was dissipated (by the influx) within 15 sec. 

 after the exhaustion. In the last series but 2 minutes are allowed between 

 the observations, but there seems to be no appreciable difference in the data so 

 far as this cause is concerned. 



Second Series. — O-- 



24°: barom. = 75.o8 cm.; (5/ = 3'"; >'=.767; 

 305000; w = 5.0X lo^'^g/cm'; 5=1.7; S'=i.95. 



■■ 21 2000; 



