

— 
June 9, 1923] 
NATURE 
791 

cannot, therefore, be given to the activities of the | radiation of light was held to be due to the presence 
Colston Research Society in the city of Bristol, the 
object of which is the promotion of research in its 
University. This Society, under a slightly different 
name, was originally founded in 1899 for the purpose 
of promoting the cause of a university at Bristol, and 
it played a most influential part in securing the 
foundation of the University ten years later. It 
then turned its attention to the assistance of a 
specific branch of university activity and chose that 
of the promotion of research. 
The Society met for its annual dinner and collection 
on June.1 under the presidency of Mr. Claude B. Fry, 
with Prof. Flinders Petrie and Sir Richard Gregory 
as the principal guests. The collection, which 
amounted to 669/., brought the total sum collected 
since its inauguration twenty-three years ago up to 
nearly 12,000/. ; 
The annual sum of about 6o00/., which is thus 
available for research, is allocated to the various 
departments of the University of Bristol by a joint 
committee of the Society and the University. It is 
interesting to note that, while the greater part of the 
funds collected is provided by local merchants and 
industrial firms, the Society accepts the term research 
in its widest sense and has recently made awards to 
the arts faculty, which will be continued so far as 
funds permit. 
In addition to the collection, an important exten- 
sion in the activities of the Society was made by 
the president for last year, Mr. Ernest Walls, which 
seems likely more and more as years go on to cement 
the relationship between the University and local 
industries. This act was the foundation of a number 
of annual Colston research fellowships. These fellow- 
ships are post-graduate in character and are ear- 
marked to a particular faculty or branch of research, 
or to a particular research problem. In those cases 
in which the research problem is of an industrial 
character and carried out, with the consent of the 
supervising professor, at the wish of the firm, addi- 
tional funds for apparatus and material are also 
available. The donor of a fellowship has access to 
the research work and receives the results of the 
work twelve months prior to publication. During 
last year fellowships were provided by the Imperial 
Tobacco Co. (botany), Messrs. J. S. Fry and Sons 
(engineering), Christopher Thomas Bros. (chemistry), 
Messrs. Packer and Sons (chemistry), Mr. Frank 
' Cowlin (medicine), and Messrs. E. S. and A. Robinson 
(chemistry). That the scheme is an undoubted 
success is borne out by the fact that at the recent 
meeting of the Society it was stated that five of the 
above fellowships were being renewed for a second 
year and that two new fellowships had been promised, 
one from Messrs. Carsons, Ltd., and the other from 
Messrs. William Butler, both in chemistry. 
To those conversant with the relations between 
universities and industry in a country like the United 
States, this may seem to be a very small organisation ; 
but in the present depressed state of the finances of 
British universities, the existence of one Society 
rallying to the support of the most essential function 
of a university is exceedingly encouraging, and the 
scheme may be commended to the notice of other 
centres of learning. 

Radiation Theory. 
ON Monday, May 28, a lecture was delivered at 
the University of Edinburgh by Prof. H. A. 
Lorentz, of the University of Haarlem, on ‘“‘ Primary 
and Secondary Radiation.’’ In the course of his 
remarks, Prof. Lorentz said that in former times the 
NO. 2797, VOL. IIT] 
in the luminous source of small particles vibrating 
about positions of equilibrium ; in the electromagnetic 
theory of light this idea became more definite, in 
that the oscillating particles were supposed to be 
electrically charged. The progress made in the last 
few years has shown that, in many cases at least, 
this explanation of radiation can no longer be main- 
tained. 
In Bohr’s theory of spectral lines, the emission of 
light is due to the transition from one stationary 
state of an atom to another. The frequency of the 
emitted radiation is determined by the change in 
the energy of the atom, and is widely different from 
the frequency really existing in the atom, in which 
the electrons freely revolve around the nucleus. 
When light is emitted by a luminous body, and, in 
general, when we are concerned with the original 
production of waves, we can speak of a primary 
radiation, whereas the term secondary radiation can 
‘be applied to those cases in which particles that 
‘are struck by incident rays thereby become centres 
of emission. 
__ There is perhaps but one case of primary radiation 
for which the old theory still holds, namely, the 
emission of electromagnetic waves by an antenna. 
If, as has been shown by the experiments of Tolman 
‘and Stewart, an electric current in a metallic wire 
consists of a motion of electrons, then this must 
-also be true of the alternating currents in the antenna, 
‘so that here the oscillatory motion of the electrons 
is seen to produce waves. 
As to the secondary radiation, this appears in 
many cases to conform to the classical laws. This 
can be illustrated by the consideration of (1) Huygens’ 
principle and his construction for the progression of 
a wave front, (2) the propagation of light ina system 
of molecules, (3) the scattering of light by molecules 
(blue of the sky, Lord Rayleigh’s formula), (4) the 
scattering of X-rays (Barkla’s experiments), (5) the 
diffraction of X-rays by crystals, it being possible, 
as has been shown by W. L. Bragg and Bosanquet, 
to calculate in this case the intensity of the secondary 
beams by means of the old theory. 
Even for the primary radiation of light, the classical 
theories need not wholly be abandoned. 

Soil Acidity and Plant Distribution. 
N important series of studies on the hydrogen 
ion concentration of the soil and its relation to 
plant distribution has been published by Carsten 
Olsen (Compt. rend. Lab. Carlsberg, xv., 1923). These 
studies deal with the hydrogen ion concentrations 
_of a series of Danish soils covered by natural vegeta- 
tion, the observed range being from Py, 3°4 to 8:o. 
The composition of the vegetation is found to be 
very closely correlated with the hydrogen ion con- 
centration of the soil, and the author considers that 
the distribution of the more important species may 
be largely determined by this factor. The number 
and density of species in a given place are also found to 
be greatest when the soil reaction approaches neutral- 
ity. Olsen further points out that the vegetation 
of alkaline soils poor in mineral nutrients bears no 
resemblance to that of very acid soils poor in nutrients. 
This section of the paper is very impressive in its 
wealth of data, and it includes exhaustive tables 
showing vegetation composition in relation to P, 
and also a large number of partial soil analyses. Only 
those who have used the field methods employed by 
Olsen can really appreciate the extent and thorough- 
ness of his investigations. 
The author then deals with the growth of typical 
