114 
NATURE 
the munificence and public spirit of Sir George Baden Powell, 
who fitted up, at his own expense, and accompanied an ex- 
pedition in his yacht Ofaréo to Novaya Zemlya. The instru- 
ments employed were provided by our Fellows, Mr. Lockyer, 
and Mr. Stone, of the Radcliffe Observatory, Oxford ; and the 
observations were entrusted to Mr. Shackleton, one of the 
computers employed by the Solar Physics Committee. In bril- 
liant weather photographic observations were made, which 
promise to yield novel results of a highly important character. 
At the request of the President of the Board of Trade the 
Council nominated, in March, Profs. Kennedy and Roberts- 
Austen as two members of a Committee to investigate the loss 
of strength in steel rails. So far as I am aware, the Committee 
has not yet made its report. More recently, in July, the 
Council, at the request of H.M. Secretary for Colonial Affairs, 
appointed a Committee to consider, and if necessary to inves- 
tigate, in conjunction with Surgeon-Major Bruce, who has made 
important researches in the matter, the disease caused in cattle 
in Africa by the Tsetse fly. The Committee is still engaged on 
the inquiry. 
We believe that the Council, in cordially responding to 
requests like the above, and in freely placing at the disposal of 
H.M. Government its scientific knowledge and its acquaintance 
with scientific men, is performing one of its most important 
functions. The Council of the Royal Society is again and 
again called upon to approach H.M. Government on behalf of 
the interests of science, and when it does so always meets with 
a cordial reception and a respectful hearing, even on occasions 
when public necessities prevent a favourable reply being given 
to its requests. In return, the Council believes it to be its duty 
{when called upon to do so), not only to place its own time and 
labour ungrudgingly at the service of H.M. Government, but 
also to ask for the co-operation of other Fellows of the Society, 
or even other scientific men not Fellows of the Society, feeling 
confident that whenever the matter in hand has practical bear- 
ings beyond the simple advancement of Natural Knowledge, 
the value of a scientific man’s time and energy will be duly | 
considered. 
Some correspondence has taken place with the War Office 
relative to resuming the borings in the Delta of the Nile, which 
were carried on for a time some years ago, and which, though 
not completed, yielded valuable results. The Expedition to the 
Soudan has, however, prevented anything being done. The 
Council learn with pleasure that the old borings, undertaken 
for a purely scientific object, have indirectly been a valuable 
means of supplying certain districts of the Delta with sweet 
water. 
If anything had been needed to justify the meetings for dis- 
cussion recently established, it would have been supplied by the 
brilliant success of that held during the present session on 
Colour Photography. On that occasion, M. Lippmann gave us 
a demonstration of results of unprecedented beauty, obtained 
by extremely simple means, though based on profound mathe- 
matical reasoning. Such meetings can only prove fruitful when 
they are held in consequence of some theme needing such a 
discussion as is afforded by a special meeting ; and their occur- 
rence must therefore be uncertain and irregular. The purpose 
for which they were instituted would be frustrated if they were 
held at times fixed in any formal way, irrespective of whether 
they were needed or not. 
Three of the informal gatherings recently instituted, limited 
to Fellows of the Society, have been held during the session, 
and were judged to be very successful. 
The Council has had occasion during the past session to 
present an address of condolence to her Majesty, the Patron of 
the Society, on the lamented death of Prince Henry of Batten- 
berg, and to the Royal Academy on the occasion of the death 
of their President, Lord Leighton. In the absence of Council, 
during the recess, I sent another message of sympathy on the 
death of Sir J. Millais. 
I had the privilege of presenting, on behalf of the Council, an 
address of congratulation to our late President, Lord Kelvin, on 
the occasion of his Jubilee, nobly celebrated in Glasgow last 
summer, by a very remarkable concourse of scientific men from 
all parts of the world, assembled to do him honour. 
Addresses were also sent to our Foreign Member, Prof. 
Cannizzaro, on the celebration of his seventieth birthday, and to | 
the University of Princeton, New Jersey, U.S.A., on the occa- 
sion of its Sesquicentenary Anniversary. 
Under the guidance of the Scientific Relief Committee, the 
NO. 1414, VOL. 55] 
[ DECEMBER 3, 1896 
Council has during the year granted 100/. to assist scientific 
persons or their relatives in distress. The Council desire to 
call the attention of the Fellows to the fact that, during the 
year, as during past years, the income of the fund has exceeded 
its expenditure, and that more aid could be given than has been 
given. With the view of increasing the usefulness of the fund, 
the Council has added to the list of those who can make repre- 
sentations to the Council concerning relief the Presidents of the 
| Mathematical, Physical, and Entomological Societies. 
I cannot but give expression to my deep regret, shared, I am 
sure, by every Fellow, that Lord Rayleigh, whose tenure of 
office as Secretary has been marked as much by faithful devo- 
| tion to the interests of the Society as by scientific brilliancy, 
has thought it right, in consequence of increasing pressure of 
other engagements, to retire. But I rejoice that the Council 
can submit to your suffrages a man well qualified to wear the 
mantle laid down by Lord Rayleigh. 
The Fellows will be pleased to learn that Mr. Rix, who was 
compelled, by the condition of his health a year ago, to resign 
the position which he had held for many years with such great 
advantage to the Society, has much improved under the lighter 
labour of the Clerkship to the Government Grant Committee. 
As his successor in the office of Assistant-Secretary, the 
Council, out of eighty-four candidates, unanimously selected 
Mr. Robert Harrison, who entered upon his duties on April 24 
last. 
The scientific work of the Society during the past year has 
been full of deep and varied interest. Early in the session the 
announcement of Rontgen’s great discovery burst upon the 
world. Its wonderful applications to medicine and surgery 
attracted universal attention to it ; and physicists everywhere 
have since been engaged in investigating the nature of the new 
rays. Perhaps no outcome of such inquiries has been more 
remarkable than the fact observed by our Fellow, Prof. J. J. 
Thomson, that the rays have the power of discharging electri- 
city, both positive and negative, from a body surrounded by a 
non-conductor ; a mass of paraffin wax, for example, behaving 
in their path for the time being like a conductor of electricity. 
It appears that Lenard had before observed the discharge of 
both kinds of electricity through air by the rays with which he 
worked. Lenard’s rays, however, differ from Réntgen’s in be- 
ing deflectable by a magnet, implying, in the opinion of most 
British physicists, that they are emanations of highly electrified 
particles of ponderable matter, while Rontgen’s are regarded as 
vibrations in the ether. The question naturally arises whether 
Lenard, in the observations referred to, may not have been 
working with a mixture of Réntgen’s rays and his own. While 
points like these are still under discussion by experts, we can- 
not but feel that the letter X, the symbol of an unknown 
quantity, employed originally by Réntgen to designate his rays, 
is still not inappropriate. 
I have before referred to Lippmann’s beautiful demonstration 
and discussion of colour photography in one of our meetings. 
Very important researches have been made both by Lord 
Rayleigh and by Prof. Ramsay into the physical properties of 
the new substance, helium, discovered by Ramsay in the previous 
session. Among their most striking results is the fact ascertained 
by Rayleigh that the refractivity ot helium is very much less than 
any previously known, being only 0°146 ; between three and 
four times less than that of hydrogen, the lowest that had before 
been observed, although helium has more than twice the density 
of hydrogen. And equally surprising is Ramsay's observation 
of the extraordinary distance through which electric sparks will 
strike through helium, viz., 250 or 300 mm. at atmospheric 
pressure, as compared with 23 mm. for oxygen and 39 for 
hydrogen. Such properties appear to indicate that in helium 
we have to do with an exceedingly remarkable substance. 
The density of helium appears to be really slightly different 
according to the mineral source from which it is obtained ; and 
this circumstance seems to give countenance to the opinion 
arrived at by Lockyer and also by Runge and Paschen, from 
spectroscopic investigation, that helium is not a perfectly pure gas. 
But whatever other gas or gases may be mixed with it, they must 
be as inert chemically as the main constituent ; for all Ramsay’s 
elaborate attempts to induce it, or any part of it, to combine 
with other bodies have entirely failed. 
Prof. Roberts-Austen, in the Bakerian lecture, brought before 
us astonishing evidence that metals are capable of diffusing into 
each other, not only when one of them is in the state of fusion, 
but when both are solid. We learned that if clean surfaces 
