 Though born in Vlieland, he moved to Delft a few years after he was born and it is there in 1705 that he started his first weather observations.In 1717 at the age of 39, though firmly established as a respected surveyor, he moved to the family farm in Rijnsburg outside Leiden and chose to study in Leiden under Herman Boerhaave, at that time the most famous scientist in the Netherlands.He signed himself in as "Krukius, medical student, born in Delft".