VOL. XXXII.] PHILOSOPHICAL TRANSACTIONS. OSfif 



Tivo General Propositions of Pappus of Alexandria, in which many of Euclid's 

 Porisms are included^ restored by Rob. Simsoiij* Professor of Mathematics at 

 Glasgow^ from the Preface to the Seventh Book of Pappus's Mathematical 

 Collections. N° 377, P- 330. 



These two propositions were afterwards incorporated into the author's large 

 posthumous works, published in 1776 by Earl Stanhope, on the same subject, 

 and where they may be read by lovers of this science with more advantage. 



* Dr. Robert Simson, professor of mathematics in the university of Glasgow, was born at West- 

 Rilbridge, in Ayrshire, l687. He was entered a student of that university about 1701, where his 

 proficiency in several branches of literature was soon remarkable. Particularly botany and other 

 branches of natural history were his chief pursuits, which led his attention to the medical science, in 

 which he afterwards took a doctor" s degree, though he never practised. In prosecution of this object 

 he went to Leyden, were he studied for some time under the celebrated Boerhaave. 



On his return to Scotland, he was induced by his friends to relinquish medicine, and turn his views 

 to the church. About this time however mathematics began to engage his mind, and at length even 

 to the exclusion of his theological studies. And a prospect soon after fortunately opened of rendering 

 this study his peculiar profession. On the resignation of Dr. Robert Sinclair, he was elected pro- 

 fessor of mathematics by the university of Glasgow in 1711, at 24 years of age. 



Soon after this appointment he came to London, to acquire more enlarged views in regard to the 

 objects of his profession, for that purpose putting himself under the immediate direction of Mr. Ditton, 

 a mathematician of considerable reputation, and master of the mathematical school in Christ's 

 Hospital. Here he commenced an acquaintance with Dr. Halley, and other eminent men of the 

 R. S. by whose advice Dr. S. early directed his attention to the restoration of the works of the 

 ancient geometricians } yet the first specimen of his talents for this difficult study, was the above 

 paper in the Philos. Trans, for 1723 j though he proceeded from this time in compiling several other 

 similar works, which however were not published till many years afterj and he never communicated 

 more than one other paper to the Philos. Trans. After a long life, spent in the severe study of the 

 pure and ancient geometry, rather indeed to the neglect of the modern analysis, he died in 1768, 

 at 81 years of age. 



Dr. Simson's works published in his life time, were, 1. Conic Sections, in 1735. 2. The Loci Plani 

 of Apollonius, in 174-9- 3. Euclid's Elements, in 1756'. After his death. Earl Stanhope was at 

 the expence of a publication of several of his posthumous pieces; viz. 1 . ApoUonius's Determinate 

 Section : 2. A treatise on Porisms : 3. A tract on Logarithms : 4. On the Limits of Quantities and 

 Ratios : 5. Some Select Geometrical Problems. 



Besides the tracts published in those posthumous works. Dr. Simson's manuscripts contained a 

 great variety of geometrical propositions, and other interesting observations on ditferent parts of the 

 mathematics; though not in a state fit for publication. Among other things however, was an edition 

 of the works of Pappus, in a state of considerable advancement, and which, had he lived, he pro- 

 bably would have published. The copy of Pappus, with all Dr. Simson's notes and explanations, 

 it seems were, soon after his death, sent by his executor to the university of Oxford, with a view to 

 publication ; but which however it does not appear has yet been accomplished. It is true. Dr. 

 Simson's copy contains a large collection of materials, among which to make a proper selection would 

 probably require considerable labour, as well as judgment. 



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