OBITUARY NOTICES. 211 



the abstruse investigations in which, he took so much interest: — 

 "The Spherical Ellipse referred to Trilinear Co-ordinates;" 

 " Cubics of the Third Class with Triple Foci, both Plane and 

 Spherical;" "Spherical Class Cubics with Double Foci and 

 Double Cyclic Arcs;" "On Sphero-Cyclides ;" "On the 

 Greneralised Problem of Contacts;" "On the Converse of 

 Stereographic Projection, and on Contangential and Coaxal 

 Spherical Circles;" and "On the Genesis of Binodal Quartic 

 Curves from Conies." To the investigation of class-cubics, both 

 plane and spherical, Mr. Jeffery devoted his intervals of leisure 

 for four years (1876-1880), and published the instalments, as 

 they were completed, in the "Quarterly Journal of Mathem.atics." 

 Mr. Jeffery had a strong desire to prepare a text-book on his 

 favourite subjects, and he had made some progress in the work ; 

 but alas ! the copy is far too incomplete to be of use, excepting 

 as a record of the studious activity of his life to the end, and 

 of his great mathematical talents. As a proof that his mental 

 powers were as active as ever, I have been informed that only a 

 few weeks before his illness, he forwarded to the London 

 Mathematical Society an important paper on the classification of 

 binodal quartics, which was read at the monthly meeting of that 

 Society, on November 12th, nine days after his death. This 

 communication closes the long line of Mr. Jeffery's papers, most 

 of which have appeared in the " Quarterly Journal of Pure and 

 Applied Mathematics," the " Proceedings of the London Math- 

 ematical Society," the "Reports of the British Association," 

 the " Proceedings of the Royal Society," and other Scientific 

 Journals. 



In addition to the non-mathematical writings of Mr. Jeffery 

 contained in the "Journal" of the Royal Institution of Cornwall, 

 he contributed to three classical works of Dr. Humphreys ; 



(1) sixty short introductory exercises to " Exercitationes 

 lambicse, or progressive exercises in Greek Iambic verse ; and 



(2) Appendixes to "Lyra Hellenica, or translations in Greek," 

 and "Manual of Greek and Latin prose composition." At the 

 Social Science Congress held at Cheltenham in 1878, Mr. Jeffery 

 read a paper "On the best means of connecting Primary and 

 Intermediate Education ;" and in 1890 he privately printed 

 "Extracts from the Religious Diary of Miss Lydia Grenfell," in 



