536 Royal Astronomical Society. Anniversary, 1 84*4?. 



Wallace's aid and recommendation were of essential service ; and if 

 anything was wanting to complete the satisfaction which he felt at 

 the result, it was to see the observatory placed under the care of his 

 friend Professor Henderson, of whose distinguished merits as an as- 

 tronomer it would be superfluous to speak to those who are in the 

 habit of attending our meetings, or reading our Memoirs. 



Although the works whicli Mr. Wallace has left behind him assure 

 him a high place as an original and inventive mathematician, the ta- 

 lents with which he was endowed by nature were, doubtless, ren- 

 dered less productive than they would have been by his want of early 

 education, his residence during the best years of his life in the coun- 

 try at a distance from congenial society, and, perhaps, still more 

 from the circumstance of so much of the time which his laborious 

 public duties left at his disposal having been consumed in the prepara- 

 tion of his numerous treatises for the Encyclopaedias. These treatises 

 being mostly of an elementary kind, and composed for the purpose 

 of explaining the principles of the various branches of mathematical 

 science, afforded little scope for originality. They possess, however, 

 all the qualities which give value to the class of writings to which 

 they belong ; being remarkable for lucidity and precision of style, 

 perspicuity of arrangement, elegance of demonstration, and admira- 

 ble adaptation for self-instruction. The article " Conic Sections" 

 in the last edition of the Encyclopaedia Britannica has been translated 

 into Russian, and used as a text-book in some of the schools for the 

 instruction of naval cadets in that empire. It has also been pub- 

 lished as a separate work, and is one of the most elegant geometrical 

 treatises on the subject in existence. Some of his other articles, 

 besides their intrinsic value, had the accessory merit of being the 

 first which were published in this country on the model of the French 

 school, when the French mathematics were greatly superior to our 

 own. His article " Fluxions," in Brewster's Encyclopaedia, was the 

 first systematic treatise in our language in which the differential no- 

 tation was used. The date of the publication is 1815 ; but, as a 

 point of history, it may be worth remarking, that this notation had 

 been adopted several years previously, both by himself and his illus- 

 trious colleague, Mr. Ivory, in their contributions to the Mathema- 

 tical Repository ; and some instances of its use occur in an English 

 work of much older date, Harris's Lexicon Technicum. 



Mr. Wallace had made himself intimately acquainted with every 

 department of mathematical knowledge, but the branch which he 

 cultivated with the greatest affection was the ancient geometrical 

 analysis. Of this subject he was a perfect master. His taste having 

 been formed by the writings of Simson, Stewart, and Playfair, lie 

 had an unbounded admiration of the elegance and correctness of the 

 Greek geometry ; and he took credit to himself for having introduced 

 the Elements of Euclid to the Military College, and restored them, 

 as a class-book, to the University of Edinburgh. Another branch 

 in which he excelled was the angular calculus, which he enriched 

 with various new series and methods of considerable importance to 

 the computer. All his memoirs exhibit ingenuity and fertility of in- 



