532 Royal Astronomical Society : Anniversary, 1 844. 



tions were proposed, as Leybourn's Repository, the Gentleman's Ma- 

 thematical Companion, and others of the same class. To this circum- 

 stance he attributed an incident which had an important influence 

 on his future life. In 1803, he received a letter, under a feigned 

 name, in which he was informed that an instructor in mathematics 

 was wanted for the Royal Military College, then established at Great 

 Marlow ha Buckinghamshire, and recommended, if he thought of 

 being a candidate for the office, to make an immediate application. 

 Inquiry being made in the proper quarter, the information was found 

 to be correct, but he ascertained also that it would be necessaiy to 

 make his application in person. In matters affecting his own inter- 

 ests the disposition of his mind was not sanguine ; and, as in the 

 present case he had no influence to employ, and no other recommen- 

 dation to carry with him than his skill in mathematics, his chances 

 of success appeared so small that he would have been deterred by 

 the length and inconveniences of the journey from thinking more of 

 the subject, had he not been encouraged by his friend Professor 

 Playfair. On his arrival at the Military College he found there were 

 several competitors ; but the persons who had to decide on the re- 

 spective qualifications of the candidates gave their decision in his 

 favour, and he was accordingly appointed to the office. 



Mr. Wallace held this appointment upwards of sixteen years, 

 during which period the whole of his leisure time was unremittingly 

 devoted to scientific study and literary labour, the fruits of which 

 appear chiefly in his numerous contributions to the two great En- 

 cyclopaedias then publishing in Edinburgh. This species of writing, 

 which is not particularly well adapted to form the basis of a perma- 

 nent reputation, was in a manner forced upon him by the circum- 

 stances of his position. On his appointment to the Perth Academy 

 he had married, and after he joined the Military College his family 

 began to increase rapidly. The inconveniences he had suffered from 

 the defects of his own early education rendered him only more soli- 

 citous that his children should not labour under any disadvantages 

 in this respect, and, as they grew up, he placed them at schools in 

 Edinburgh. His official income being insufficient for this expense, 

 he was led to engage in the works now referred to, rather with a 

 view to add to his means, and to enable him to discharge a sacred 

 duty, than for the sake of any distinction he was likely to get by 

 them. No individual, perhaps, was ever less influenced by consi- 

 derations of a worldly nature, or more ready to bestow time and la- 

 bour upon objects from which he could neither receive nor expect any 

 remuneration whatever. 



In 1808 he contributed a paper to the Royal Society of Edin- 

 burgh, entitled " New Series for the Quadrature of the Conic Sec- 

 tions, and the Computation of Logarithms," and containing some 

 very remarkable formula; for the rectification of circular arcs, with 

 analogous expressions for the sectors of the equilateral hyperbola and 

 the logarithms of numbers ; all deduced from elementary principles, 

 and without the use of the differential calculus or any equivalent 

 method. At the time the paper was published, he believed the se- 



