ADVEKTISEMENT. 
rjlHE present volume contains 93 papers numbered 706 to 798, published, 
with the exception of one series, for the most part in the years 1878 
to 1883. This series is constituted by the articles which Professor Cayley 
wrote for the Encyclopedia Britannica between the years 1878 and 1888 ; 
it seemed desirable to place these together in the same volume, in spite 
of the departure from the chronological arrangement which governs the 
sequence of the papers in the volumes generally. The Syndics of the 
University Press desire to acknowledge their obligation to Messrs Adam 
and Charles Black, Publishers of the ninth Edition of the Encyclopedia 
Britannica, for their courteous consent in allowing these articles to be 
included in the Collected Mathematical Papers. Exact references to the 
volumes, from which the articles are extracted, will be found in the Table 
of Contents. 
The frontispiece to the present volume is a reproduction by Mr 
A. G. Dew-Smith, of Trinity College, of a photograph of Professor Cayley 
which he made in the year 1885. The Syndics of the Press desire to 
acknowledge their obligation to Mr Dew-Smith.