Vili Contents. 
Notes on the Breeding of Forficula auricularia. By H. H. BRINDLEY 
The comparison of nearly equal electrical resistances. By G. F. C. SEARLE. 
(Five figures in Text) 
The Distribution of the Stars in relation to Spectral Type. By Professor 
A. 8S. EDDINGTON : : : : ; : 
The oxygen content of the river Cam before and after receiving the Cam- 
bridge sewage effluent. By J. E. Purvis and E. H. Brack. (Three 
figs. in Text) : é ‘ : § ; 3 
On Root Development-in Stratiotes aloides L. with special reference to 
the occurrence of Amitosis in an embryonic tissue. By AGNES ARBER. 
(Communicated by Dr ArBER.) (Plates VIII and IX) . 
Amitosis in the Parenchyma of Water-Plants. By R. C. M°Lman. 
(Communicated by Professor SzEwarRD.) (One fig. in Text) . 
The History of the occurrence of Azolla in the British Isles and in Europe 
generally. By A.S. Marsa. (Communicated by Professor SEwarD) 
A Simplification of the Logic of Relations. By N. WIENER. (Com- 
municated by Mr G. H. Harpy) . : : : 5 : 
A Double-Four Mechanism. By G. T. Bennert. (Two figs. in Text.) 
(Plate X) . : 
On the Nature of the Internal Work done during the Evaporation of a 
Tnqud. By R. D. Kureman. (Two figs. in Text) . 
The Work done in the Formation of a Surface Transition Layer of a 
Liquid Mixture of Substances. By R. D. KiuEEMAN 
The ionisation produced by certain substances when heated on a Nernst 
filament. By Frank Horton. (Two figs. in Text) 
Fluctuations of sampling in Mendelian Ratios. By G. Upny YULE 
A Case of Repulsion in Wheat. By F. L. ENcLEDOw. (Communicated 
by Professor BIFFEN) — 
The determination of the best value of the coupling-ratio from a given set 
of data. By F. L. ENauEpow and G. Upny YtLe . 
A Contribution to the Theory of Relative Position. By Noreert 
WIENER. (Communicated by Mr G. H. Harpy) . 
On an Application of the Molecular Field in Diamagnetic Substances. 
By A. E. OxnEy 
Thompsonia, a little known Crustacean Parasite. (Preliminary Note.) 
By F. A. Ports, M.A., Trinity Hall. (Two figs. in Text) . 
The gall-forming Crab, Hapalocarcinus. (Preliminary Note.) By 
F, A. Porrs, M.A., Trinity Hall. (One fig. in Text) . : 
