t 5 8 On the ORIGIN and 



done very early, and long before the publication of the Loci 

 Plant in 1749- The account he gives of his progrefs, and of 

 the obftacles he encountered, will be always interesting to ma- 

 thematicians. " Poftquam vero apud Pappum legeram Porif- 

 " mata Euclidis colle&ionem fuifTe artinciofiihmam multarum 

 " rerum. quae fpectant ad analyfin difficiliorum et generalium 

 " problematum, magno defiderio tenebar, aliquid de iis cognof- 

 " cendi; quare faepius et multis variifque viis turn Pappi propofi- 

 " tionem generalem, mancam et imperfeclam, turn primum lib. i. 

 " Porifma, quod folum ex omnibus intribus libris integrum ad- 

 " hue manet, intelligere et reftituere conabar ; fruftra tamen, 

 " nihil enim proliciebam. Cumque cogitationes de hac re 

 " multum mihi temporis confumpferint, atque molefta? admo- 

 " dum evaferint, firmiter animum induxi hasc nunquam in 

 " pofterum inveftigare ; praefertim cum optimus geometra 

 '• Halleius fpem omnem de iis intelligendis abjeciiTet. Un- 

 " de quoties menti occurrebant, toties eas arcebam. Poftea 

 " tamen accidit, ut improvidum et propofiti immemorem in- 

 " vaferint, meque detinuerint donee tandem lux quaedam efful- 

 " ferit, qua? fpem mihi faciebat inveniendi faltem Pappi pro- 

 " poiitionem generalem, quam quidem multa inveftigatione 

 " tandem reftitui. Haec autem paulo poft una cum Porifmate 

 " primo lib. i. imprefia eft inter Tranfactiones Phil, anni 1723,. 

 " No. 177 *." 



The propofitions here mentioned, as inferted in the Philo- 

 fophical Tranfaclions for 1723, are all that DrSiMsoN publish- 

 ed on the fubjecl of Porifms during his life, though he conti- 

 nued his investigations concerning them, and fucceeded in re- 

 storing a great number of Euclid's propofitions, together with 

 their analyns. The propofitions thus reftored form a part of 

 that valuable edition of the pofthumous works of this geometer 

 which the mathematical world owes to the munificence of the 

 late Earl Stanhope. 



6. The 



* R03. Simson Op. reliqua, p. 319. 



