7 Artisans, merchants and the use of small telescopes
For what purpose were these small telescopes manufactured? Two bone telescopes were found in cesspits in Amsterdam. Two wooden telescopes were found on board of ships. Because of the low magnification, the telescopes were probably not for astronomical but for terrestrial use. They were, however, not used for navigation; in navigation a different type of telescope with a higher magnification was used. This indicates that the small telescopes were a kind of pocket telescopes for personal use. They could, for example, be used as opera-glasses or for personal use on ships.
Little is known about the manufacturers of such telescopes. The manufacture of a bone tube and the grinding of lenses are different crafts and it is possible that the bone tubes and the lenses were made by different artisans. People with a scientific education, such as the famous Dutchmen Spinoza or Huygens, knew how to make lenses. But in the 17th and 18th centuries merchants in the Dutch Republic had the influence and money to require knowledge about optics, and some of them even made scientific instruments themselves (Zuidervaart 2004). In the Kalverstraat in Amsterdam telescopes could be bought, for example, at the knife-shop of Coenraad Metz. He sold all sorts of optical instruments (Gawronski 1994: 274-275).
Although the development of the telescope rapidly spread throughout Europe, the pocket telescope was still a luxury item. It is not surprising that these bone telescopes were found in Amsterdam. Amsterdam was an important trading town and a centre of craft. Telescopes were also manufactured in this city. Perhaps more undiscovered telescopes are yet to be found in museum and archaeological collections. Further research, both archaeological and historical, must be done to reveal more about the artisans and merchants and also about the use of these small telescopes.