J 4 \ Royal Society. 



containing many valuable series of investigations, and very important 

 discoveries. He first attacked the great problem of the determination 

 of the orbits of comets by general methods, which display all the re- 

 sources of his analysis ; though astronomers have not found it expe- 

 dient to make use of his methods in the actual calculation of their 

 elements, which is the only proper test of their practical value, though 

 it may not be decisive of their theoretical perfection. He was the 

 author of the method of the least squares of the errors, for the pur- 

 pose of determining the most probable mean amongst the results of 

 a great number of observations, of which such extensive use is now 

 made in practical astronomy : a celebrated and most useful theorem 

 in geodesy goes by his name ; and there are few departments of ana- 

 lysis or of dynamics which have not been benefited by his labours. 



M. LeGendre was associated with Mechain and Cassini in the 

 operations which were instituted in 17S7, and finished in 1790, for 

 the junction of the meridians of Paris and London. He was one of 

 the three Members of the Council nominated for the purpose of 

 introducing the new metrical system into France in 1795, and he 

 constructed the formula? employed for the calculation of the tables for 

 the centesimal division of the quadrant. He was nominated, both 

 during the Imperial and subsequent Government, to various public 

 employments, chiefly, however, of an honorary nature, requiring no 

 great sacrifice of time or attention, — a fortunate circumstance, when 

 it is considered to what important labours the leisure of his long life 

 appears to have been devoted. 



The next name which I feel called upon to notice is that of Fran- 

 cisco de Borja Garcao Stockler, Baron da Villa da Praia, a 

 Lieutenant- General in the Portuguese army, and formerly Secretary 

 of the Academy of Sciences of Lisbon : he was the author of several 

 Papers in the Transactions of the Lisbon Academy, chiefly on subjects 

 connected with the developement of functions, and also of a volume 

 of Poems. In 1795 he published his Methodo dos Limites, and in 1 824 

 his Methodo inverso dos Limites. In this latter work, written late in 

 life, he adopted the opinions of the well-known Hoene de Wronski, 

 which led to its rejection by the Academy of Lisbon, upon the report 

 of two Academicians, when it was offered to them for publication. 

 His works are not of a kind to exercise much influence upon the pro- 

 gress of science, and some of them are examples of the danger of deal- 

 ing with formulae of such great generality that their proper import and 

 derivation are not very clearly understood by those who use them. 



Of the five Foreign Members whose names appear in the lists of 

 the additions which the Royal Society has received during the last 

 year, it is with deep regret that I observe those of two of them also 

 in the record of its losses : the first is that of Professor Meckel of 

 Halle, the second that of M. Desfontaines of Paris. 



Dr. JohnFrederickMeckel, Professor of Anatomy in the Univer- 

 sity of Halle, was the third member of a family singularly illustrious 

 in the annals of physiological and anatomical science. His grand- 

 father, at the beginning of the last century, was probably the great- 

 est anatomist of his age, and was the founder of that collection which 







