SECTIONAL TRANSACTIONS.—M. ; 508 
Tuesday, September 18. 
11. Joint Discussion with Section K on Virus Diseases of Plants. 
(See p. 492.) 
12. Mr. G. P. Mitn.—The Commercial Value of Indigenous Strains 
of Pasture Grasses. 
Results obtained from pure line breeds of the pasture species of indigenous 
grasses as compared with ordinary commercial strains. 
Results of cultivated grass seeds in this country as compared with Denmark 
and other foreign countries. 
13. Dr. W. R. G. Arxins and Mr. E. W. Fenton.—The Hydrogen 
Ion Concentration of the Soil in Relation to the Distribution of 
Pasture Plants. 
Grasses and clovers sown to form pastures are frequently found to dis- 
appear, being ousted by species native to the particular soil type. Accordingly 
an investigation seemed advisable to ascertain the limits within which different 
species flourish naturally. It is noticeable that wild white clover may be found 
on soil as acid p.H. 5.6, whereas IJ/edicago maculata is found from p.H. 6.7—7.8. 
Holeus mollis, u. lanatus, and Cynosurus cristatus have been observed to occur 
from p.H. 5.4~7.2, whereas Agrostis vulgaris, Agropyrum repens, and Lolium 
perenne extend from p.H. 5.8-8.0. 
In the afternoon an excursion took place to Messrs. Garton’s at 
Warrington and to Col. Lyon’s Farm at Appleton. 
REFERENCES TO PUBLICATION OF 
COMMUNICATIONS TO THE SECTIONS 
AND OTHER REFERENCES SUPPLIED BY AUTHORS. 
Under each Section, the index-numbers correspond with those of the papers in 
the sectional programmes (pp. 424-503). 
References indicated by ‘ cf.’ are to appropriate works quoted by the authors of 
papers, not to the papers themselves. 
General reference may be made to the issues of Nature (weekly) during and sub- 
sequent to the meeting, in which résumés of the work of the sections are furnished. 
Section A. 
4. Cf. W. M. Smart, Navigation, Position Line Tables (J. D. Potter, shortly). 
10. Cf. T. Smith, ‘ On Balancing Errors of Different Orders,’ in Proc. Physical Soe. 
32, p. 141 (1919-20). 
11. Observatory, 46, No. 593, Oct. 1923. Cf. Monthly Notices, R.A.S., 82, pp. 170-1, 
Jan. 1922; 83, pp. 204-15, Jan. 19238. 
19. Nature, 112, No. 2816, p. 589, Oct. 20, 1923. 
22. Nature, Sept. 22,1923 (Summary); to be published in full in Phil. Mag. Cf. 
24, Cf.‘ Aninvestigation of the Angle of Contact between Paraftin Wax and Water,’ 
Phil. Mag., Ser. 6, 46, No. 272, pp. 244-256, Aug. 1923. 
