SIMSON. 497 



successful cultivator of science, Earl Stanhope,* it 

 was, after his death, published, with his restoration of 

 Apollonius' treatise De Sectione determinata, a short 

 paper on Logarithms, and another on the Method of 

 Limits geometrically demonstrated, the whole forming 

 a very handsome quarto volume ; of which the 

 Porisms occupies nearly one-half, or 277 pages. 



This work is certainly the master-piece of its distin- 

 guished author. The extreme difficulty of the subject 

 was increased by the corruptions of the text that re- 

 mains in the only passage of the Greek geometers which 

 has reached us, the only few sentences in which any 

 mention whatever is made of porisms. This passage is 

 contained in the preface or introduction to the seventh 

 book of Pappus, which we have already had occasion 

 to cite. But this was by far the least of the difficul- 

 ties which met the inquirer after the hidden treasure, 

 the restorer of lost science, though Albert Girard 

 thought or said, in 1635, that he had restored the Po- 

 risms of Euclid. As we have seen, no trace of his 

 labours is left ; and it seems extremely unlikely that 

 he should have really performed such a feat and given 

 no proofs of it. Halley, the most learned and able of 

 Dr. Simson's predecessors, had tried the subject, and 

 tried it in vain. He thus records his failure : " Hac- 

 tenus Porismatum descriptio nee mihi intellecta nee 

 lectori profutura." These are his words, in a preface 

 to a translation which he published of Pappus's 

 seventh book, much superior in execution to that of 

 Commandini. But this eminent geometrician was 



* Grandfather of the present Earl. 



2 K 



