IV 
CONTENTS. 
No. page 
VII. An Unnoticed Point in the Theory of Newton’s Rings. By 
J. Marshall, M.A., B.Sc., University College, Nottingham. 
Communicated by Professor W. Peddie, D.Sc., ... 51 
(Issued separately March 25 , 1920 .) 
VIII. The Effect of Weather Changes on Soil Temperatures. By 
Captain T. Bedford Franklin, B.A. (Cantab.), ... 56 
(Issued separately March 25 , 1920 .) 
IX. On the Quaternionic System as the Algebra of the Relations 
of Physics and Relativity. By Professor W. Peddie, . 80 
(Issued separately May 29 , 1920 ). 
X. Note on Pfaffians with Polynomial Elements. By Sir Thomas 
Muir, M.A., LL.D, F.R.S., 83 
(Issued separately May 29 , 1920 .) : 
XI. The Daily Temperature Curve. By L. Becker, M.A., Ph.D., 
Professor of Astronomy in the University of Glasgow, . 89 
(Issued separately , 1920 .) 
The Poppers published in this part of the Proceedings may be 
had separately , on application to the Publishers, at the follow- 
ing Prices : — 
No. I . 
. Price Is. 
No. VII 
. Price 
Is. 
No. II . 
„ Is. 8d. 
No. VIII : . 
• }) 
2s. 8d. 
No. Ill 
,, Is. 4d. 
No. IX , t 
Is. 
No. IV . 
>> 
No. X 
• ») 
Is. 
No. V . 
. „ Is. 
No. XI . « . 
>> 
Is. 8d. 
No. VI . 
. „ is. 
* 
