Career
He describes himself in his work as Hugo Sempilius Craigbaitaeus, probably making him the Hew Sempill of Craigbait and Langside found in local genealogies, where his birth is given as 1590. He also served as procurator of the Royal Scots College in Madrid (now located in Salamanca). Sempill"s work was essentially a compilation and many pages consist of little but a list of names of writers in various scientific genres.
Sempill also wrote Experentia Mathematice.
De compositione et divisione numerum, linearum, quadratorum. (Madrid, 1642). The crater Simpelius on the Moon is named after him.
The name was originally assigned by Riccioli in 1651.