PHILOSOPHICAL TRANSACTIONS 
OF THE 
ROYAL SOCIETY OF LONDON 
Series A, VOL. 206, pp. 69-100. 
ON THE PERIODICITIES OF SUNSPOTS 
BY 
ARTHUR SCHUSTER, F.R.S. 
LONDON: 
PUBLISHED FOR THE ROYAL SOCIETY 
BY DULAU AND CO., 37, SOHO SQUARE, W. 
CONTINENTAL AGENTS, MESSRS. FRIEDLANDER AND SON, BERLIN. 
1906. 
A 403. 
Price One Shilling and Sixpence. 
6 . 6.06 
