PROCEEDINGS 
OF THE 
ROYAL SOCIETY OF EDINBURGH. 
SESSION 1919-20 
Part I] 
YOL. XL. 
[Pp. 1-96 
CONTENTS. 
NO. 
I. Notices of Fellows, Honorary and Ordinary, 
deceased. By The General Secretary, 
{Issued separately January 31, 1920.) 
II. The Cooling of the Soil at Night, with Special Reference 
to Late Spring Frosts (II). By Captain T. Bedford 
Franklin, B.A. (Cantab.). Communicated by The 
General Secretary, 10 
{Issued separately February 3, 1 920.) 
III. Note on the Determinant whose Matrix is the Sum of Two 
Circulant Matrices. By Sir Thomas Muir, M.A., LL.D., 
F.R.S., 23 
{Issued separately February 3, 1920.) 
IV. Note on Mr Quilter’s Photographs of Mirage. By The 
General Secretary, ........ 33 
{Issued separately February 23, 1920.) 
V. The Absorption of X-Rays. By Dr R. A. Houstoun, Lecturer 
on Physical Optics in the University of Glasgow, . . 34 
{Issued separately February 23, 1920.) 
VI. Note on the Scattering of X-Rays. By Dr R. A. Houstoun, 
Lecturer on Physical Optics in the University of Glasgow, 43 
{Issued separately March 25, 1920.) 
[ Continued on page iv of Cover . 
EDINBURGH: 
Published by ROBERT GRANT & SON, 107 Princes Street, and 
WILLIAMS & NORGATE, 14 Henrietta Street, Covent Garden, London, W,C. 2. 
Price Eleven Shillings. 
