DEcEMBER 3, 1896] 
which have become permanent parts of our scientific literature. 
While carrying out this highly important original work in 
Geology, Sir Archibald has most materially contributed to the 
advancement and diffusion of scientific knowledge by his many 
educational works upon Geology and Physical Geography. His 
**Elementary Lessons on Physical Geography” has passed 
through several English and foreign editions; his ‘‘ Outlines 
of Field Geolagy ” is now in its fifth edition ; and his article 
on Geology—originally contributed to the ‘ Encyclopedia 
Britannica” in 1879—was afterwards expanded by him into his 
well-known ‘‘ Text-book of Geology,’’ which has become the 
acknowledged British standard of Geology in general. 
RoyaLt MEDAL. 
Prof. C. V. Boys. 
The other Royal Medal is awarded to Prof. Boys, who has 
given to physical research a method of measuring minute forces 
far exceeding in exactness any hitherto used, by his invention of 
the mode of drawing quartz fibres, and by his discovery of their 
remarkable property of perfect elastic recovery. 
Prof. Boys has himself made several very important researches 
in which he has employed these fibres to measure small forces. 
Using a combination of a thermo-junction with a suspended coil 
in a galvanometer of the usual D’Arsonval type, a combination 
first devised by D’Arsonval himself, Prof. Boys developed the 
idea in the microradiometer, an instrument rivalling the bolo- 
meter in the measurement of small amounts of radiation. Its 
sensitiveness and accuracy were obtained in part by the use of a 
quartz fibre to suspend the coil, in part by the admirable design 
of every portion of the instrument. Prof. Boys was the first to 
show its value in an investigation into the radiation received 
from the moon and stars. 
In this great research on the value of the Newtonian con- 
stant of attraction, Prof. Boys used quartz fibres to measure the 
gravitation forces between small bodies by the Michell- 
Cavendish torsion method. He redesigned the whole of the 
apparatus, and, calculating what should be the dimensions and 
arrangements to give the best results, he was led to the remark- 
able conclusion that accuracy was to be gained bya very great 
reduction in the size of the apparatus. -This conclusion he 
justified by a determination of the value of the Newtonian 
constant, which is now accepted as the standard. 
Prof. Boys has also made some remarkable studies by a photo- 
graphic method of the motion of projectiles, and of the air 
through which they pass. 
All his work is characterised by the admirable adjustment of 
the different parts of the apparatus he uses to give the best 
results. His instruments, are, indeed, models of beauty of 
design. 
RuMFORD MEDAL. 
Prof. Philipp Lenard and Prof. W. C. Réntgen. 
In the case of the Rumford Medal, the Council have adopted 
a course, for which there are precedents in the awards of the 
Davy Medal, but which is, as far as the Rumford Medal 
itself is concerned, a new departure. They have decided to 
award the Medal in duplicate. It has often happened in the 
history of science that the same discovery has been made almost 
simultaneously and quite independently by two observers, but 
the joint recipients of the Rumford Medal do not stand in this 
relation to each other. Each of them may fairly claim that his 
work has special merits and characteristics of its own, To-day, 
however, we have to deal not with points of difference, but with 
points of similarity. There can be no question that a great 
addition has recently been made to our knowledge of the pheno- 
mena which occur outside a highly exhausted tube through which 
an electrical discharge is passing 
Many physicists have studied the luminous and other effects 
which take place within the tube ; but the extension of the field 
of inquiry to the external space around it is novel and most 
important, There can be no doubt that this extension is chiefly 
due to two men—Prof. Lenard and Prof. Réntgen, 
The discussion which took place at the recent meeting of the 
British Association at Liverpool proved that experts still differ 
as to the exact meaning and causes of the facts these gentlemen 
have discovered. No one, I believe, disputes the theoretical 
interest which attaches to the researches of both ; or the practical 
benefits which the Rontgen rays may confer upon mankind as 
aids to medical and surgical diagnosis. But whatever the final 
verdict upon such points may be, the two investigators whom we 
NO. 1414, VOL. 55] 
NATURE 
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honour to-day have been toilers in a common field, they have 
both reaped a rich harvest, and it is, therefore, fitting that the 
Royal Society should bestow upon both of them the Medal 
which testifies to its appreciation of their work. 
Davy MEpat. 
Prof. Henrt Motssan. 
The Davy medal is given to Prof. Henri Moissan. 
Notwithstanding the abundant occurrence of fluorine in nature, 
the chemical history of this element and its compounds has until 
recently been scanty in the extreme, and, as far as the element in 
the free state is concerned, an entire blank. And yet from its 
peculiar position in the system of elements, the acquisition of a 
more extended knowledge of its chemical properties has always 
been a desideratum of the greatest scientific interest. 
The frequent attempts which have been made from time to 
time to clear up its chemical history have been constantly baffled 
by the extraordinary difficulties with which the investigation of 
this element is beset. 
Thanks to the arduous and continuous labours of M. Moissan, 
this void has been filled up. Tle has effected the isolation of 
fluorine in a state of purity, and prepared new and important 
compounds, the study of which has placed our knowledge of the 
chemical and physical properties of this element on a level with 
that of its immediate allies. 
During the last few years M. Moissan has turned his attention 
to the study of chemical energy at extremely high temperatures, 
and by the aid of the electric furnace, which he has contrived, 
he has succeeded in obtaining a large number of substances 
whose very existence was hitherto undreamt of. It is impossible 
to set bounds to the new field of research which has thus been 
opened out. The electric furnace of M. Moissan has now 
become the most powerful synthetical and analytical engine in 
the laboratory of the chemist. 
On studying the accounts which Moissan has given of his 
researches, we cannot fail to be struck with the originality, care, 
perseverance and fertility of resource with which they have been 
carried on. The Davy Medal is awarded to him in recognition 
of his great merits and achievements as an investigator. 
. Darwin MEDAL, 
Prof. Giovanni Battista Grasse. 
The Darwin Medal for 1896 is awarded to Prof. Grassi, of 
Rome (late of Catania), for his researches on the constitution of 
the colonies of the Termites, or White Ants, and for his dis- 
coyeries in regard to the normal development of the Congers, 
Murzenze, and Common Eels from Leptocephalus larvee. 
From a detailed examination of the nature and origin of the 
colonies of the two species of the Termites which occur in the 
neighbourhood of Catania, viz., Zermes luctfugus and Callo- 
termes flavicollés, he was able to determine certain important 
facts which have a fundamental value in the explanation of the 
origin of these and similar polymorphic colonies of insects, and 
are of first-rate significance in the consideration of the question 
of the share which heredity plays in the development of the re- 
markable instincts of ‘* neuters,” or arrested males and females, 
in these colonies. Prof. Grassi has, in fact, shown that the food 
which is administered by the members of a colony to the young 
larvee determines, at more than one stage of their development, 
their transformation into kings or queens, or soldiers or workers 
as the case may be, and the value of these researches is increased. 
by the observations. which he has made on the instincts of the 
different forms, showing that they do not in early life differ from 
one another in this respect, and are all equally endowed with the 
potentiality of the same instincts. These do not, however, all 
become developed and cultivated in all alike, but become 
specialised, as does the physical structure in the full-grown 
forms. 
A very different piece of work, but having a no less important 
bearing on the theory of organic evolution, is that on the Lepto- 
cephali. These strange, colourless, transparent, thin-bodied 
creatures, with blood destitute of red corpuscles, had been re- 
garded as a special family of fishes, but have been proved by 
Grassi’s patient and long-continued labours to be larval forms 
of the various Mureenoids. The most astonishing case is that 
of the Common Eel (Azguélla vulgaris), the development of 
which had been a mystery since the days of Aristotle. It had 
been long known that large eels pass from rivers into the sea 
at certain seasons, and that diminutive young eels, called in this 
country Elvers, ascend the rivers in enormous numbers. But, 
