- 76 — 



uncertain whether the Journal will be continued. I should have 

 been particularly interested in the memoir upon the circumscribed 

 developables^') and in your residts relating to the triple tangent 

 planes — the memoir miist I think be more closely connected 

 with the researches of M' Salmon^'-) than with anything in the 

 paper of mine to which you refer — besides his memoirs in the 

 Cambridge and Dublin and Quarterly Mathematical Journal, 

 J believe there will be shortly published in the Transactions 

 of the Royal Jrish aeademy an important memoir by him upon 

 the theory of Reciprocal surfaces. 



1 hope soon to have the pleasure of sending you my second 

 memoir upon Quantics — I have also written and presented to 

 the Royal society a third memoir upon the same subject but it 

 will be some time before that is pubhshed, it contains the system 

 of the Covariants and Contravariants of a ternary cubic, and 

 gives I think the materials for a complete discussion of the 

 theory of curves of the third order. I find that besides Steiners 

 curves Pp. Qo, Ro (Grelle t XLVII p. 4) which for a curve of 

 the third order reduce themselves to a single curve P U of the 

 third class, there is another curve Q U of the third class of 

 which I have not yet discovered the geometrical representation; 

 I hope to write something upon this for Grelles Journal. I shall 

 not fail to enquire after the memoirs you have kindly send me, 

 if I do not receive them in good time; I have however the 

 memoir upon Resultants/-^) which I read with thegreatest interest. 

 I was particularly delighted with the way in which you estabUsh 

 the degree in which a certain factor enters into the Resultant 

 I shall be at all times most happy to hear from you upon 

 mathematical subjects. I have the honor to be, Sir 



your obedient servant 

 A. Cayley. 



2 Stone Buildings 



London, 19. Mar. 1856. 



'') Diese Abhandlung scheint nie gedruckt worden zu sein. 



'-) Mit George Salmon ist L. Schlaefli meines Wissens nicht in 

 direkte Beziehung getreten. 



'») Über die Resultante eines Systems mehrerer algebraischer Glei- 

 chungen, ein Beitrag z. Theorie der Elimination. (IV. Band der Denkschriften 

 der math.-naturwiss. Klasse der Wiener Akademie 1852.) 74 S. in Folio. 



i 



