94 
NATURE 
{ NOVEMBER 26, 1903 
Pror. Witi1aM F. Duranp, professor of marine engineer- 
ing, has been appointed acting director of Sibley College, 
Cornell University, in succession to the late Prof. Thurston. 
Dr. Morris W. Travers has been appointed professor of 
chemistry in University College, Bristol, in succession to 
Prof. Sydney Young, F.R.S. Dr. F. E. Francis, lecturer 
in chemistry, has been promoted to the rank of assistant 
professor in the college. 
SPEAKING at Limerick last week in distributing prizes to 
the pupils of the Municipal Technical, Science and Art 
Schools, Sir Horace Plunkett remarked that the whole 
country had now taken up the work of technical education 
with a quickness, receptivity, and responsiveness which he 
was told by educational experts had not been witnessed 
in any country under similar economic conditions, and in 
so short a time. There was now scarcely a corner of 
Ireland where the people were not showing an anxiety and 
practical interest to take up a scheme which had been in- 
troduced under the auspices of the Department of Agri- 
culture and Technizal Instruction. 
In the course of an address at Liverpool on Saturday last 
Sir Philip Magnus remarked that our very existence as a 
nation depended upon our continued educational advance. 
There was a startling contrast between the liberal expendi- 
ture in America and Germany upon specialised university 
research and the small sums spent here. This country had 
little to learn from the method of teaching in American 
schools, but what we could and must learn if we were to 
recover lost ground was a changed attitude towards educa- 
tion itself. Few manufacturers in this country yet realised 
the economy and industrial advantages of attaching to their 
works intelligence departments staffed with scientific ex- 
perts. He was glad to say, however, even in this respect 
the outlook was improving, and there were many signs of 
brighter days in store. 
SOCIETIES AND ACADEMIES. 
Lonpon. 
Royal Society, November 19.—‘‘ The Sensation of Light . 
produced by Radium Rays, and its Relation to the Visual | 
Purple.’’ By W. B. Hardy and H. K. Anderson. 
When a few milligrammes of radium bromide are brought 
near the head in the dark a sensation of diffuse light is 
produced. The authors find that this is not due to any 
direct response on the part of the retina, the optic nerve, or 
the brain, but to a fluorescence of the tissues of the eye- 
ball, notably of the lens and of the retina itself, excited by 
the 8 and y rays. 
The visual purple of the retina is not bleached by any 
of the radium rays. 
The authors point out in passing the peculiarly high 
opacity of the eyelid to the rays, as compared with the skin 
of other parts of the body. 
=¢Physical Society, November 13.—Dr. R. T. Glazebrook, | 
F.R.S., president, in the chair.—Sir Oliver J. Lodge read a | 
paper on means for electrifying the atmosphere on a large 
scale. Twenty years ago the author was engaged with Mr. 
J. W. Clark on an investigation of the dark spaces seen 
near hot bodies placed in illuminated smoke. The existence 
of these dust-free spaces was discovered by Tyndall, and the 
phenomenon had been investigated by Lord Rayleigh. 
Tyndall worked with high temperatures, and attributed the 
effect to the burning of the dust near the hot body. Such, 
however, cannot be the case, as the spaces exist when in- 
organic dust, such as oxide of magnesium, is used. The 
conclusion at which Messrs. Lodge and Clark arrived (see 
Phil. Mag., 1884) was that the result was due to an aérial 
bombardment from the hot wire which drove the particles 
away, and they tried the effect of electrifying the hot body 
to see if there was any modification of the dark space. A 
new phenomenon was discovered, the whole of the dust 
being driven to the sides of the containing vessel. This 
experiment was shown by the author at the British Associ- 
ation meeting in Montreal in 1884, and subsequently, on a 
larget scale, at the Royal Institution. In the latter experi- 
ment two pieces of wire gauze, connected to the terminals 
NO. 1778, VOL. 69] 
of an electric machine, were placed opposite each other in 
a smoke-filled chamber, through which a current of smoke 
was slowly passing. Upon electrifying the plates the smoke 
ceased passing, the dust particles cohered, hovered in the 
air, and were either driven to the sides of the chamber or 
fell to the bottom. In the case of mist, electrification of 
steam in a bell jar converted it into fine rain. It seems 
therefore possible that rain might be produced by the elec- 
trification of a cloud. Sir Oliver Lodge has tried at Liver- 
pool to disperse fogs by discharging electricity into them. 
For this purpose a large mast was erected on the roof of the 
University College buildings. It terminated in a bundle of 
points, to which electricity was conveyed from a Wimshurst 
machine by a wire supported by specially constructed in- 
sulators. In order fo drive electricity from a point far re- 
moved from a surface a high potential is necessary, and 
sometimes a large gas flame was used to supplement the 
points. Upon one occasion the discharge of electricity from 
the flame was sufficient to keep a clear space of 50 or 60 
yards radius in a dense feg. The author had hoped to 
| induce the Mersey Dock Board to try the principle on a 
large scale, having a series of positive discharges on one 
side of the river and a series of negative discharges on the 
other ; but he felt a certain reluctance in recommending the 
method to practical men so long as it was necessary to 
derive the current from a Wimshurst machine. A dynamo 
would b2 a more suitable generator if it were possible to 
get a sufficiently high potential. The way out of the diffi- 
culty is to rectify a high-tension alternating current, and 
Sir Oliver Lodge has for some time been considering the 
possibility of doing this by utilising Cooper-Hewitt mercury 
lamps. A study of these lamps has led him to believe that 
their rectifying power is much assisted by the outside 
me.allic coating which surrounds the mercury electrode, 
and which is connected to the positive terminal of the lamp. 
Ia order to rectify an alternating discharge, four lamps are 
s» arranged in the form of a quadrilateral that, when the 
leads from the terminals of an alternating transformer are 
connected to two opposite corners, two unidirectional 
currents are obtained from the other corners. Experiments 
have been made at Birmingham by sending the current from 
a high-frequency alternator (3000 ~ per sec.) through the 
primary of an induction-coil and connecting the terminals 
of the secondary to the rectifiers. The length of the rectified 
spark can be increased by putting a number of lamps in 
series in each arm of the quadrilateral arrangement. Sir 
Oliver Lodge performed an experiment at the meeting to 
show the dissipation of fog by electrification. The current 
from an alternator was passed through the primary of a 
coil and the terminals of the secondary connected to the 
rectifiers, twelve lamps in all, three in series in each arm. 
This arrangement is capable of giving a rectified spark 2 or 
3 inches long, the unidirectional nature of which can be 
proved by passing it through a Crookes or a Rontgen tube. 
Some magnesium wire having been burnt under a large 
bell jar to fill it with a cloud of magnesium oxide, the jar 
was then illuminated by the light from an electric lamp. 
Passing through the base-piece upon which the bell-jar was 
placed was a conductor which terminated in a point inside 
the jar. When the terminals between which the rectified 
discharge was passing were separated and the other end 
of this conductor was joined to one of them, the electricity 
streaming from the point into the clouded atmosphere caused 
an immediate deposition of the magnesium oxide.—Sir 
Oliver Lodge also described an arrangement for driving 
mercury pumps, designed by Mr. B. Davies and himself. 
Chemical Society, November 5.—Prof. W. A. Tilden, 
F.R.S., president, in the chair.—The following papers were 
read :—The reduction of hydrazoic acid, by Mr. W. 
Cooke. The products were hydrazine and ammonia in 
place of the expected cyclic nitrogen hydride.—Preliminary 
note on the viscosity of liquid mixtures, by Messrs. A. E. 
Dunstan and W. H. C. Jemmett. The viscosity curve 
of a mixture of two non-associated liquids is a straight 
line, of a non-associated with an associated liquid, a line 
convex to the axes, and of two associated liquids, a line 
concave to the axes.—Contribution to the study of the 
reactions of hydrogen peroxide, by Mr. J. McLachlan. 
The evolution of oxygen induced by the addition of solutions 
of hydrogen peroxide to acidified solutions of potassium 
