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 also made observations in astronomy. He published dissertations De vi attrice; De corporum gravitate et levitate; De cognitione 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 twenty-three years; and his funeral oration was pronounced four days after by M. Gravis.