6386 REPORT—1899, 
5, Report on the Heat of Combination of Metals in the Formation 
of Alloys.—See Reports, p. 246, 
6. Report on Radiation from a Source of Light in a 
Magnetic Field,—See Reports, p. 63. 
7. On the Production, in rarefied Gases, of Luminous Rings in rotation 
about Lines of Magnetic Force. By C. E. 8, Putiuirs. 
The apparatus used in this investigation consisted of an approximately spherical 
glass bulb, the ends of which were left open for the purpose of inserting two soft 
iron electrodes, half an inch in diameter, through air-tight flanges which them- 
selves were cemented to the glass. The bulb was about 23 in. in diameter, and 
the electrodes were chosen of a sufficient length to enable them, while almost 
meeting at the centre of the bulb, to project outwards slightly beyond the rims of the 
flanges. A side tube was attached for the purpose of connecting the apparatus to 
a Sprengel air-pump and McLeod vacuum gauge. Two powerful electro-magnets 
were then adjusted, so as to strongly magnetise the electrodes when necessary. 
A low pressure having been produced in the bulb by the action of the air- 
pump, leading wires were attached to the iron electrodes to enable the discharge 
from the secondary of an induction coil to be passed through the rarefied gas. 
Under these conditions the effects produced in the usual glow-discharges by the 
magnetisation of the electrodes could be conveniently examined. It was seen that 
at @ pressure represented by ‘008 mm. of mercury, and with the discharge just 
able to pass in the bulb (the magnets meanwhile remaining unexcited), on shutting 
off the current from the induction coil and completing the magnet circuit, a 
luminous ring appeared within the bulb in a plane at right angles to the lines of 
force and in rotation about the magnetic axis. The number of such rings can be 
varied by special devices, and their brightness largely depends upon the electro- 
static condition of the outer surface of the glass bulb. The circumferential speed 
of the ring or rings rapidly dies down, and the sense of the rotation reverses when 
the magnetic polarity of the electrodes is reversed. The rings, when once formed, 
usually last for many seconds, sometimes for a minute; and they momentarily 
brighten before disappearing, when the electrodes cease to be magnetised. The 
appearance of the rings is greatly affected by bringing charged bodies up to the 
outside of the bulb. 
The effect also depends upon the manner of stimulation of the rarefied gas 
within the bulb, It is necessary to obtain a particular distribution of charged 
particles in order to get the best results when the magnet is excited. The shape 
of the magnetic field is also of importance. A single magnetic electrode projecting 
into the electrified gas shows the effect fairly well. Experiments with external 
magnetic electrodes have not given reliable results, the glow produced in such 
cases being generally irregular, An attempt will be made later on, when the 
experiments are more complete, to show that the formation of these luminous 
rings is associated with actions observed by the writer in connection with a 
separate research, the results of which were embodied in a note communicated to 
the Royal Society last June under the heading ‘Diselectrification produced by 
Magnetism.’ 
8. Note on Deep-Sea Waves, 
By VauGuan Cornisu, M.Sc., 2.CS., FR.GS. 
The following questions are raised or discussed:—(1) What is the amplitude 
H and the wave-length L for different distances A from the windward shore, the 
wind being supposed to blow with velocity V of say 30 knots until the sea has 
reached a steady state? (2) Can wind create waves of considerable amplitude, 
