Marcu 12, 1914] 
intermediate stratum of air that we must ascribe 
(exempli gratia) the doubt whether Kinchinjunga or 
K, is to hold the honourable position of second in 
altitude to Everest amongst the world’s highest 
peaks. eer. He 
REPORTS OF MUSEUMS, 
“T’HE report of the Bristol Museum for the year 
ending September 30, 1913, records praiseworthy 
activity, especially in the department of vertebrate 
zoology. Three plates show how attractively some of 
the more important specimens are displayed. A tiger 
shot by the King in Nepal, and presented by his 
Majesty, has been set up by Messrs. Rowland Ward, 
in a crouching attitude among bamboo stems, while 
the background, painted by Mr. Stanley Lloyd, shows 
the shooting-party approaching on elephants in the 
distance. Three springboks are placed near the 
margin of a veldt, on which other animals are brows- 
ing; this background was painted by Mr. G. E. 
Butler. The picturesque group in which pheasants 
are feeding (harmlessly) in the stubble, is backed by 
a view of Ashton Park, with the Clifton Suspension 
Bridge in the distance, composed by Mr. A. Wilde 
Parsons. This utilisation of really competent artists 
is an example to be followed. The geological depart- 
ment has not shared in the general progress, and 
considering the recent work of Vaughan and others 
in the west of England, this fact is rightly deplored 
by the committee. 
With the aid of local naturalists, the small staff 
of the Hancock Museum at Newcastle-upon-Tyne has 
during the past two years accomplished some excel- 
lent work. From a 45-ft. Rorqual (Balaenoptera 
borealis) cast ashore near Amble, the complete 
skeleton, including ear-bones, hyoids, and rudimentary 
hip-bones, was obtained. The larger bones have been 
satisfactorily prepared in a sand-pit; but the smaller 
bones which were macerated as usual in water made 
so little progress that they have now been transferred 
to sand. <A promising beginning was made with 
classes from the elementary schools, each of which 
went through a definite course of six lessons, given 
by the teachers, who were first rehearsed in the lesson 
by the curator, Mr. E. L. Gill. Unfortunately this 
regular system could not be followed in the second 
year, owing to the overcrowded curriculum of the 
schools, and the visits are now of small educational 
value. Perhaps the committee recently appointed by 
the British Association may devise some scheme that 
will overcome this difficulty. 
The report of the Manchester Museum for the year 
1912-13 bears witness to plenty of hard work, but 
contains nothing of outstanding interest. It is, how- 
ever, worth reading in order that one may admire 
the healthy spirit of cooperation as regards museum 
matters that breathes in Manchester. Representatives 
of the University, of the City Council, and of sub- 
scribers among the outer public, constitute the com- 
mitte of management. The City Council has in- 
creased its grant from 4ool. to 8001. per annum. 
Professors of the University supervise and aid the 
museum staff. In the transference of the Egyptian 
antiquities to the new building, which, with its cases, 
was provided by Mr. Jesse Haworth, valuable help 
was given by a number of ladies and gentlemen. 
Several ladies have maintained a supply of fresh 
flowers, and at least four other names are mentioned 
in connection with solid pieces of work of more expert 
character. To a museum combining so many forces 
there naturally flow considerable donations, -both in 
money and in kind. 
NO. 2315, VOL. 93]| 
NATURE 43 
RADIATION OF GAS MOLECULES 
MNGLLED BY LIGHT: 
ieee = first Guthrie lecture of the Physical Society 
was delivered on February 27, at the Imperial 
College of Science, South Kensington, by Prof. R. W. 
Wood, of Johns Hopkins University, Baltimore. The 
lecture has been established in memory of Prof. F. 
Guthrie, who was professor of physics in the Royal 
College of Science, and was founder of the society, 
the first meeting having been held in his lecture 
theatre at the college in 1874. Before Prof. Wood’s 
lecture, Prof. G. Carey Foster gave a short biography 
of Guthrie, who was born in 1833 and died in 1886, 
and Sir Oliver Lodge recalled some personal remini- 
scences of him. Prof. Wood’s lecture is summarised 
in the subjoined abstract, published by the Physical 
Society. 
The emission and absorption of light by molecules 
and the allied phenomenon of dispersion have led us 
to the conception of something within the atom which 
is capable of responding to light waves in much the 
same way as a tuning-fork responds to sound waves 
of the same frequency as its own, and many mathe- 
matical treatments have been built up which explain 
more or less perfectly many of the phenomena in ques- 
tion. These still leave us very much in the dark as 
to what is going on. Helmholtz explained absorption 
by introducing a frictional term into his equations of 
motion for the atom, and though this led at once to 
an expression which represented anomalous dispersion, 
it left us ignorant of how the energy absorbed by 
the molecules was transformed to heat, or how the 
mean velocity of the molecules was increased by the 
excitation of vibrations within them. Planck avoided 
| this difficulty by considering that the energy abstracted 
from the beam of light is re-emitted, though at the 
time the only experimental evidence was to be found 
in selective reflection, which occurs only in liquids and 
solids. 
What becomes of the absorbed energy in the case of 
a gas? This was what he had been asking himself 
for many years. While he did not require a working 
model of the atom, he could not, however, be satisfied 
by an equation in which absorption was represented 
by a frictional term or selective reflection predicted 
by the occurrence of an imaginary quantity. 
The problem of the constitution of the atom is one 
which must be approached from many sides, as it is 
improbable that any single mode of attack will reveal 
the secret. The spectroscope alone has proved itself 
powerless, one great difficulty being that in all known 
methods of exciting spectra one got ‘tthe whole or 
nothing.” 
Flames, arcs, sparks, and vacuum-tube discharges 
set a host of vibrations simultaneously in operation 
within the atom, and resulted in a complex of lines 
which were difficult to interpret. 
His line of attack had been to maintain the mole- 
cules in as calm and tranquil a state as possible, by 
keeping them cool, and then to excite them to radia- 
tion by the application of an alternating electro- 
magnetic field of a definite frequency—usually called 
monochromatic light. That this method has in some 
degree simplified matters was proved by the fact that 
sodium vapour could be made to emit only one of the 
D lines instead of the usual two. 
The conditions necessary to stimulate radiation in 
this way varied considerably with the nature of the 
element studied. He would begin, however, with the 
simplest case, that of a vapour which exhibits a single 
, absorption line and emits radiations similar in every 
respect to the exciting radiations when stimulated by 
