CONTENTS. 
VOL. XVIII. 
The Conductivity of Hatremely Dilute Acid and Alkali Solutions. By 
| 4H. Parns, M.A., B.Sc. and G. T. R. Evans, B.Sc. (Five figs. 
in Text) : : : : ; : 5 : 5 
Studies in Synthetic Logic. By Norpert WIENER, Ph.D. (Com- 
municated by Mr G. H. Harpy) . : : : : 
| eI 3: : ‘ 
The Determination of the Prime or Composite Nature of Large Numbers 
by Fermat's Theorem. By H. C. Pocxuineton, M.A. . 
Auperiment on the harmonic motion of a rigid body. By G. F. C. 
SEARLE, Sc.D., F.R.S. (Four figs. in Text) . 
Some Insect Flagellates introduced into Vertebrates. By H. B. Fantuay, 
 D.Se., B.A., and Anniz Porter, D.Sc. (Plate I) 
The Cuticula of Insects as a means of defence against Parasites. By 
_ Witi1am R. Tompson. (Communicated by Mr F. A. Porrs) . 
The Shortest Line Dividing an Area in a Given Ratio. By NorBert 
| Wiener, Ph.D. (Communicated by Mr G. H. Harpy) 
| 
‘The Colour Variations of the Fauna associated with Crinoids. By 
| F. A. Porrs, M.A. (One fig. in Text) . 
Preliminary notes on some Problems connected with Respiration in 
Insects generally and in Aquatic forms in particular. By G. L. 
_ PurseR. (Communicated by Mr F. A. Ports.) (One fig. in Text) 
On the Conditions of Instability of Electrified Drops, with Applications 
to the Electrical Discharge from Inguid Points. By JoHN ZELENY, 
B.A., Ph.D. (Communicated by Professor Sir J. J. THomson.) 
(Three figs. in Text) : : : : 3 : , 
5 
f 
The Origin of the ‘ Wolf-note’ in Bowed Stringed Instruments. By G. W. 
Wuire. (Communicated by Professor Sir J. J. THomson.) (Plates 
i111) 
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