The Author of the Introduction, Robert P. Multhauf, is head curator of the department of science and technology in the United States National Museum, Smithsonian Institution.
Introduction
Robert P. Multhauf
The telescope was invented about 1600. It was brought to America about a half-century later, and within another century had become a commonplace appurtenance to the library of the cultivated gentleman.[1]
Throughout this period, from Galileo to Herschel, the telescope found use in scientific astronomy, although the possibility of contributing to the science of astronomy by simple observation diminished continuously after the time of Galileo. Herschel’s work had aimed at the advancement of scientific astronomy through increasing spectacularly our powers of vision, just as had that of Galileo in the 17th century and of Hale in the 20th. But even in Herschel’s time the monstrous size of the instrument required made the project something of a national effort. The telescopes of the 18th-century American gentleman were already toys, as far as the astronomer was concerned.
However, the telescope had another, if less glamorous, use in the 18th century. This was its use in positional astronomy, in the ever more precise measurement of the relative positions of objects seen in the heavens. Measurement had been the purpose served by pre-telescopic astronomical instruments, the sighting bars of the Ptolemaic observers of Alexandria and the elegant quadrants of Tycho Brahe. For a time after the invention of the telescope the professional astronomer resisted the innovation, but by the end of the 17th century the new optical instrument was being adapted to the quadrant and other instruments for the precise measurement of the positions of heavenly bodies in relation to the time-honored astronomical coordinates. By the late 18th century telescopes were found serving three relatively distinct purposes: the increased magnification of the sky in general (in which use Herschel’s 48-inch reflector had made all others obsolete): the more precise measurement of planetary and stellar positions (and, conversely, of the Earth’s shape) by means of the quadrant, vertical circle, zenith sector, and similar instruments; and the simple edification of the educated but not learned classes, who wished not only to see what the astronomer saw, but to have an instrument also useful for looking occasionally at interesting objects on earth.
Of these three purposes the second was the most unimpeachably scientific. It is remarkable that the earliest American-made telescopes of which we have knowledge were made for this purpose and not for the mere gratification of the curiosity of the educated layman. These are the telescopes of the remarkable Philadelphia mechanic, David Rittenhouse (1732-96). In an atmosphere not unlike the intellectual democracy that characterized the formation of the Royal Society a century earlier in London, Rittenhouse began as a clockmaker and ended as president of the American Philosophical Society, our counterpart of the Royal Society, in Philadelphia. He demonstrated not merely that an instrument-maker was capable of being a scientist, but also that the work of the instrument-maker, as it had developed by the late 18th century, was in itself scientific work. One of several observers assigned by the Society to the observation of the transit of Venus in 1769, he constructed instruments of the most advanced types, apparently employing European lenses, and used the instruments himself. Of these, a 1¾-inch refractor mounted as a transit instrument stands in the hall of the Philosophical Society. It is probably the oldest extant American-made telescope.
Rittenhouse made other telescopes which survive, notably two zenith sectors now in the U.S. National Museum of the Smithsonian Institution,[2] but he does not appear to have made them for commercial sale. In the history of telescope-making in America he seems to have been something of a “sport.” Not only were the instruments which still grace the desks of Washington, Jefferson, and others, of European manufacture, but the earliest observatories in the United States (eleven between 1786 and 1840) were outfitted exclusively (except for the Rittenhouse observatory) with European instruments.[3] In its endeavor to establish a permanent observatory even Rittenhouse’s own Philosophical Society seems to have thought exclusively in terms of instruments of European manufacture.
It must therefore have required some courage for Amasa Holcomb, 43-year-old Massachusetts surveyor, to approach Professor Silliman of Yale in 1830 with a telescope of his own construction. In the autobiography printed here, Holcomb states that all the telescopes used in this country before 1833 had been obtained in Europe, and indicates that thereafter “the whole market was in his hands during thirteen years,” a period which would fall, apparently, between 1833 and 1845. It should be mentioned, although it is no conclusive negation of Holcomb’s claim, that the New York instrument-maker Richard Patten in 1830 built a telescopic theodolite that was designed by Ferdinand Hassler for use on the Wilkes Expedition, and was subsequently used at the observatory of the Navy’s “Depot of Charts and Instruments” in Washington.[4] We do not know the source of Patten’s lenses.