John de, professor of natural philosophy and mathematics at Utrecht, was born at Gorcum in 1620. He had uncommon skill in dissecting animals, and was a great lover of experiments. He made also observations in astronomy. He published dissertations De vi attrici; De corporum gravitate et levitate; De cognitio Dei naturali; De lucis causa et origine, &c. He had a dispute with Isaac Vossius, to whom he wrote a letter printed at Amsterdam in 1693; wherein he criticises Vossius's book De natura et proprietate lucis; and strenuously maintains the hypothesis of Descartes. He died in 1675, after he had been professor 23 years; and his funeral oration was pronounced four days after by M. Graevius.