PROCEEDINGS 
OF THE 
ROYAL SOCIETY OF EDINBURGH. 
SESSION 1907-8. 
Part IV.] YOL. XXVIII. [PP- 257-336. 
CONTENTS. 
NO. PAGE 
XVI. The Problem of a Spherical Gaseous Nebula. By Lord 
Kelvin, ....... 259 
( Issued separately May 6, 1908.) 
XVII. The Theory of Skew Determinants in the Historical Order 
of Development up to 1865. By Thomas Muir, LL.D., . 303 
{Issued separately May 13, 1908.) 
XVIII. Sunset and Twilight Curves, and Related Phenomena. By 
D. M. Y. Sommer ville. ( Communicated by Professor 
Dyson.) With Three Plates, . . . .311 
{Issued separately May 14, 1908.) 
EDINBURGH : 
Published by ROBERT GRANT & SON, 107 Princes Street, and 
WILLIAMS & NORGATE, 14 Henrietta Street, Covent Garden, London. 
MDCCCCVIII. 
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