In his own words in his Personal Narrative of Travels…. Humboldt carried "A three-foot achromatic telescope by Dolland, intended for observation of Jupiter's satellites." (Alexander von Humboldt. Personal narrative of travels to the equinoctial regions of the New continent, during the years 1799-1804, by A. von Humboldt and A. Bonpland. translated from the French by Helen Maria Williams, 1814, p 34.)
Selected on-line examples of early 18th and 19th-century achromatic telscopes that share similar features to Humboldt's at the Royal Museums, Greenwich, include:
This telescope is designed for astronomical as well as terrestrial observations. It closely reflects the design and capabilities of c. 1800 achromatic telescopes such as the three-foot achromatic telescope by Dolland used by Humboldt, as seen in the examples at Greenwich linked above.
The telescope is 38” long closed, with a 3” objective lens. It is displayed with a right angle eyepiece for celestial observations. Note the telescoping stabilizers (to reduce vibration) and boxwood and brass altitude and azimuth adjusting wands. There is rack and pinion focusing using the knurled knob on the right side of the main telescope tube near the eyepiece end. A small finder scope is attached on the opposite side of the tube. The telescope is engraved Widdifield & Co., Boston around the eyepiece mountThere are a variety of eyepieces, filters etc. not on display (see below). The original curved legs were cut short in the past, thus the ‘barrel’ display-mount.The slide-on objective cover is displayed on the box to the left of the telescope base while the two threaded protective caps for the right angle prism are displayed between the legs on the telescope base.There are two terrestrial erecting eyepiece tubes and five astronomical eyepieces. The terrestrial eyepiece assemblies are 16 3/4" and 16" long, respectively, each with a black brass annular disk on the end away from the eyelens. (see image) Each has a screw-on polished brass cap with pivoting cover (see image). The five celestial eyepieces are stamped 277, 475, 1333, 1666, and 2222. (see image of stamped 277) Each has an associated brass tube (277–2222 long to short) with annulus that the eyepiece may thread into. There are also four different density solar fillters that screw onto the eyepieces. (See image of four eyepieces, tubes, and solar filter, 1666 not shown.) Alternatively the eyepiece can be threaded into the right angle prism which in turn threads into the tube, as is shown in the image of the telescope above.
According to Allen Wissner of Antique Microscopes (website)*
"Daniel Brown Widdifield was born in Boston on May 26, 1800. He began his apprenticeship first with the optician Thomas Pons and later with John Peirce after which he commenced business in his native city. In the Columbian Centinel newspaper of Boston dated June 6, 1837, appeared an advertisement promoting Daniel B. Widdifield, Optician, located at No. 141 Washington Street opposite the Old South Meeting-house. The ad shows a pair of spectacles. According to the Websters Instrument Makers Database, the firm traded under the name D. B. Widdifield from 1828 to 1837. Thereafter, from 1838 to 1868, instruments were signed D. B. Widdifield & Co. or just Widdifield & Co. It is not certain exactly when the firm went out of business. Instruments that appear to postdate 1868 are known. Besides the microscope described here, it is known that the firm sold telescopes, thermometers, and barometers and it can be assumed that a variety of other scientific instruments as sold by other mid-century opticians were available from the shop. There are no indications that the firm manufactured any of the instruments sold, although further research would be needed to confirm this. The 1860 Boston directory places Widdifield & Co. (Daniel B. Jr, and George F. Widdifield) at 148 Wash. bds 26 West Cedar and indicates an association with J. L. Millar. In the 1883 edition of The Tech, the newspaper of the Massachusetts Institute of Technology, an advertisement appeared by Wm. K. Millar & Co. located at 38 West St. in Boston offering a variety of instruments to the students. This advertisement states that this firm is the " successors to Widdifield & Co." A floor-mounted telescope signed " Widdifield & Co., Boston”, assumed to be from C. 1890 (but probably pre-dating 1883), and described as a “Bardou type” is known to have been recently sold. In addition, another telescope signed “ Bardou et Fils a Paris Pour Widdifield & Co. Boston” is located at the National Maritime Museum in Dublin. It is dated mid to late 19th century."
* Downloaded 8 August 2013 from http://www.antique-microscopes.com/universal.html
© R. Paselk
Last modified 13 August 2013