SECTIONAL TRANSACTIONS.! 
SECTION A.—MATHEMATICAL AND PHYSICAL 
SCIENCE. 
(For references to the publications elsewhere of communications entered in 
the following list of transactions, see p. 503.) 
Thursday, September 13. 
1. Joint Discussion with Sections B and G on Cohesion and 
Molecular Forces, opened by Sir Wiri1am Brace, F.R.S. 
2. Prof. 0. G. Darwin, F.R.S.—The Recent Work of Prof. A. H. 
Compton on ihe Scattering of X-rays. 
3. Prof. C. G. Barxua, F.R.S.—X-ray Absorption and the J Discon- 
tinuities. 
4. Dr. W. M. Smarr.—Lecture on Navigation. 
Friday, September 14. 
5. Senatore Viro Vourerra, For. Mem. R.S.—Liquid Jets. 
Hitherto the case considered has been that of movements parallel to a plane, 
using the theory of functions. In the present research several cases are solved 
of symmetrical and unsymmetrical movements which are not plane movements. 
6. Sire Outver Lopez, F.R.S.—Matter and Radiation. 
Speculations as to the relation between radiation and matter and the possible 
generation of electrons by otherwise waste radiation. The momentum of a 
wave-front and some photo-electric phenomena are responsible for the sugges- 
tion, which has probably occurred to others. The velocity with which all 
matter is moving may also be taken into consideration. 
In the theory of relativity, matter and energy are closely related, and an 
expression is forthcoming for the absolute energy of a moving body; whereas 
what has been always hitherto dealt with is the energy of relative motion. The 
absolute term in the expression for energy must be energy of constitution, and 
its form suggests a specialised portion of a turbulent ether circulating with the 
‘velocity of light. Turbulence confers upon an incompressible massive fluid the 
power of transmitting tranverse waves. 
All ordinary motions could then be regarded as only local modifications of 
this general ethereal circulation, in the same sort of way as.a wind is a modifi- 
cation of mclecular motion. Ordinary motion would be equivalent to change 
of mass, and might be expressed as a slight addition to the individualised 
and specific portion of ethereal circulation which constitutes the original mass. 
What we call matter would be the way in which this kind of localised ether 
motion appeals to our senses. In the case of an electron, the absolute term in — 
the expression for energy exhibits itself to us quantitatively as the energy of 
its electrostatic charge. 
* Excursions which were arranged as part of the programmes of certain 
Sections, for the purpose of field work, &c., are recorded in these transactions. — 
In addition, other items in the general programme of excursions were arranged 
with reference to the interests of particular Sections. 
