SECTIONAL TRANSACTIONS.— B, C. 345 



Law 4. Crushed sand coming from a grinding mill is comfosed of homogeneous grades 

 of crushed sand, in which the distribution of the numbers of the particles with their 

 diameters cannot be altered, no matter how often we regrade the sand. 



These statistically homogeneous grades of sand may be considered as the 

 unalterable elements which compose a given mixture of sand particles. In such 

 a homogeneous grade the distribution of the particles follows the probability law. 



This was proved by separating out the sand coming from a tube-mill (and whose 

 particles follow the compound-interest law, N=ae-''-r) into separate grades by 

 repeated air elutriation. 



One of these grades was then air-elutriated some eight or nine times without in 

 any way altering the distribution of the particles therein, which was found to follow 

 the probability law, N=«e''-'^ , where N is the number of particles of a given diameter 

 X ; a and b are constants. 



9. Dr. E. S. Semmens. — Hydrolysis by Light Polarised by Colloidal 



Particles : Contribution to the Study of Enzyme Action. 



The undoubted selective effect of polarized light in biochemical reactions, which 

 lias been abundantly confirmed during the past three years, together with the fact 

 that enzymes, being colloidal, exhibit the Tyndall polarizing effect very strongly, 

 suggests that the polarization of incident radiation is an important factor in enzyme 

 action. 



To demonstrate this, the following experiments were made : — 



A small, flat-bottomed, thin-walled flask, containing a suspension of well-washed 

 potato-starch grains in distilled water, was irradiated on its base by light, polarized 

 %y colloidal particles of a strong taka-diastase solution contained in an outer beaker. 

 In the control, the flask was waxed and the outer beaker held plain tap-water. 



At intervals of two or three days, a few drops from each flask were examined on 

 a microscope slide and the results were briefly as follows : — 



(a) After bright illumination, the grains in the first flask were found to be 

 breaking down rapidly, those in the control being practically intact. 



(b) After feebler light, the grains were seen to be hollow, hydrolysis commencing 

 from within and extending by canals to the exterior. 



On heating with Fehling solution, reduction was observed and particles of cuprous 

 oxide were seen revolving inside the grains. 



(c) With longer exposure, on slowly drying, crystals were seen forming within 

 the grain or exuding from it. The liquid became viscous and, after several weeks, 

 bundles of needle-shaped crystals slowly formed in the liquor. 



(d) Under certain conditions, a fatty film was seen, together with hexagonal or 

 rhomboidal crystalline plates, produced apparently from the broken-down shells of 

 the grains. 



As in all these cases the enzyme was outside the vessel containing the substrate, 

 these visible signs of hydrolysis point strongly to the conclusion that the orientation 

 of the light (or heat) vibration is at least one of the factors of enzyme activity. 



SECTION C.-GEOLOGY. 



(For references to the publication elsewhere of communications entered in the 

 following list of Transactions, see page 445.) 



Thursday, August 5. 



1. Presidential Address by Prof. S. H. Eeynolds on Progress in the 



Study of the Lower Carboniferous {Avonian) Rocks of England 

 and Wales. (See p. 65.) 



2. Prof. W. J. SoLLAS, F.R.S.— TAe Geology of the Oxford District. 



