346 Mr. H. F. Newall. [Feb. 21, 



quantity of water in the bottom of the jar it was noticed that the 

 electrification did not commence to be perceptible generally till about 

 the end of the first minute ; and that it went on augmenting per- 

 ceptibly for a minute or more after the bubbling was stopped. The 

 following experiment was therefore tried several times. One of 

 ns stood leaning over the jar, with the head about 10 ins. above it, 

 and the mouth so partly closed that breathing was effected sideways ; 

 another blew the bellows ; and another took the readings of the 

 electrometer. After bubbling had been going on for some minutes, 

 and the readings were rising gradually (4 volts per 10 minutes, as in 

 18), blowing was stopped. As soon as the bubbling ceased, the 

 first-mentioned observer, without moving his head or his body (see 

 7, regarding the necessity to have the electrometer screened from 

 outside influences) blew into the jar to displace the negatively 

 electrified air in it. In every case the electrometer reading showed 

 instantly a small rise in the positive direction. 



In the carrying out of these experiments we have received much 

 valuable help from Walter Stewart, M.A., and Patrick Hamilton, 

 B.Sc. 



33. The very interesting experiments described by Lenard, in his 

 paper on the Electricity of Waterfalls,* and by Professor J. J. 

 Thomson, on the Electricity of Drops, f show phenomena depending, 

 no doubt, on the properties of matter to which we must look for 

 explanation of the electrical effects of bubbling described in our 

 present communication, and of the electrification of air by drops of 

 water falling through it, to which we have referred as having been 

 found in previous experiments which were commenced in 1890 for the 

 investigation of the passage of electrified air through tubes. J 



II. " Note on the Spectrum of Argon." By H. F. NEWALL. 

 Communicated by LORD HAYLEIGH. Received February 

 14, 1895. 



In the course of a spectroscopic investigation in which I have been 

 for some time past engaged, a line spectrum, which so far as I was 

 able to make out was unknown, has frequently presented itself upon 

 my photographs. It appeared in May and June, 1894, under condi- 

 tions which led me to call it, for the sake of convenience, " the low- 

 pressure spectrum." After their announcement at the Oxford 

 meeting of the British Association, it seemed for many reasons 



* ' Wiedemann's Annalen,' 1892, vol. 46, pp. 584636. 

 f ' Phil. Mag.,' April, 1894, vol. 37, pp. 341358. 



J " Electrification of Air by a Water Jet." By Magnus Maclean and Makita 

 Goto, 'Phil. Mag.,' August, 1890, vol. 30, pp. 148 1S2. 



