CONTENTS. 



PAGE 



Note on some Physical Properties of Sodium Vapour. By P. V. Bevan . 129 



A Null Method of Measuring Small Ionisatiom. By Norman R. 



Campbell , , , . 132 



On the Reflection of Sound at a Paraboloid. Part II. By The fee*. 



H. J. Sharpe . . . ' . 133 



The Abortive Development of the Pollen in certain Sweet-Peas (Lathyrus 



odoratus). (With Plates I. and II.) By R.- P. Gregory . . 148 



The seed-bearing habit in the Lyginodendrece. By E. A. Newell Arber 158' 



Experiments on Penetrating Radiation. By H. L. Cooke . . .160 



A suggestion as to the nature of the " walnut " comb in Fowls. By 



W. Bateson and R. C. Punnett 165 



The Absence of Isomerism in substituted Ammonium Compounds. By 



H. 0. Jones . . ... . . . . . . .369 



The rate of recombination and the size of gaseous ions. By Professor 

 J. J. Thomson . . . . . 



Proceedings at the Meetings held during the Session 1904 — 1905 . .174 



