The Amsterdam burgomaster Johannes Hudde was born in 1628 and died in 1704. He started his career as a promising mathematician, which he later gave up for his municipal activities. He was also noted for his work as an optician.
Hudde was the first Dutchman to use blown lenses for microscopes. It is fairly certain that, by 1663, he blew small globules of lenses by heating a little piece of glass at the point of a needle over a flame. The globules were later mounted on wood. This method had a defect: the interference by the needle-point created a not perfect sphere, and some iron-oxydes could contaminate the glass surface. The French traveler Monconys left us a description of this method:
… M. Hudde estimé tres habil dans l’Algebre, et qui a trouvé la façon des petits microscopes à une seule lentille, dont il en donna un à M. un à moy, et à mon fils. Il nous dit la maniere de laquelle il tailloit ces petites lentilles. Il faisoit simplement fondre à la lampe du cristal bien pur de soy, d’où il oste le sel qui est dedans, en le faisant rougir, car alors ce sel vient tout à la superficie du verre, dont on l’oste apres avec facilité: le verre donc estant bien pur, il en prend un peu au bout d’une petite verge de fer rouge, où il s’en attache la quantité qu’on veut, et lors le faisant fondre à la lampe, et tournant la verge de fer, au bout de laquelle il est, il s’arrondit de lui mesme parfaitement, Quelquefois, au lieu de crystal, il prend un petite vessie de verre pleine d’eau qui fait le mesme effet.
Mr. Hudde, judged very skilled in Algebra, found a way of making small microscopes with only one lens, of which he gave one to M., one to myself, and one to my son. He told us the way how he produced these small lenses. With a lamp he simply melted some crystal free of spot, from which he purged the salt that was inside by heating it, because this salt comes completely to the surface of the glass from which it can be taken away easily. Now the glass being pure, he takes a bit of it and puts it at the end of a small rod of red iron, on which he attaches the quantity that he desires and while melting it at the lamp, and rotating the iron rod, at the end of which the glass is, it becomes perfectily round. Sometimes, instead of crystal, he uses a small part of a plain water glass that has the same effect.
Hudde introduced microscopy to some other important Dutch microscopists. He worked with the excommunicated Jewish philosopher Baruch Spinoza, and corresponded with Christiaan Huygens and Jan Swammerdam.