Mr. Holcomb's ability to manufacture telescopes 

 which should bear a comparison, on favourable terms, 

 with the best four and five feet achromatics now in the 

 country, having been established by the report of the 

 committee in May, 1834, their attention was chiefly 

 directed to ascertaining the degree of perfection to 

 which he has attained in his art, by his persevering 

 efforts during the past year. Accordingly, the remarks 

 which follow are made with reference to the larger 

 telescope, of about ten feet focal length, eight inches 

 aperture, and with a positive eye-piece, giving a power 

 of about 900, and the surface of the field of view- 

 nearly twice as great as that of a Gregorian, and one- 

 third greater than that of an achromatic telescope, 

 under similar circumstances. 



The view of the moon with its rugged surface, its 

 ridges of mountains, and the endless variety of indenta- 

 tions on its surface, was interesting beyond description, 

 and exceeded any thing of the kind the committee 

 have ever witnessed. 



Saturn's ring, though not in a favourable position, 

 was seen manifestly double, for the first time in this 

 country, as far as the information of the committee 

 extends. 



The companion of Polaris appeared as a star of the 

 fourth or fifth magnitude, to the unassisted eye. 



The double stars, Castor, ji Draconis, 4 and 5 

 e Lyrae, and 44 Bootes, were distinctly separated, and 

 the dark space between them made evident. The 

 last mentioned, consisting of two stars of the fifth mag- 

 nitude, distant 3" m.ade a fine appearance; they were 

 soft, and well defined, and there were no scattering 

 rays of light, as was the case with Castor, in both 

 instruments. 



A class of closer doubles stars, of which 6 Coronse, 

 distant 1".2., and f Bootes, distant 1".4,, m.ay serve 

 as examples, was acknowledged by the artist, last year, 

 to be too difficult for his telescope. This has furnished 

 a stimulus for his exertions, and the complete division 

 of the latter, as witnessed by the committee on the 

 present occasion, has been the reward of his disinter- 

 ested labours. The discs of the two stars in f Bootes 

 appeared to be tangent to each other. The commit- 

 tee have no evidence that the same has been effected 

 by any other telescope in the country. 



For the purpose of finding the limit to the power of 

 Mr. Holcomb's telescope, the committee called his 

 attention to a class of still closer stars; among them 

 were mentioned, f Cancri, ju^ Bootes, « Coronas, 36 

 Andromedae, and e Arietis, the last of which is only 

 divisible by two telescopes now in use, viz.: the Dorpat 



telescope, and the twenty foot reflector of Sir John 

 Herschel. These stars, distant from 0".6. to 1".0., 

 are made to appear with their discs tangent to each 

 other in those celebrated instruments, as appears by 

 their notes appended to the observations contained in 

 their printed catalogues. It is almost needless to add, 

 that Mr. Holcomb acknowledged these stars to be too 

 difficult for any telescopes he has yet made. 



It may seem presumptuous to compare the small 

 instrument of Holcomb with the chefs d'oeuvre of 

 British and German genius; but, thanks to the ad- 

 mirable labours of the Herschels, of Struve, and of 

 South, observers are enabled, through their printed 

 catalogues, to compare together the optical capacities 

 of their telescopes in distant regions. Accordingly 

 it appears from an examination of these catalogues, 

 and of Holcomb's instruments, that what the best 

 telescopes in Europe can do upon stars distant 0".6., 

 can be done upon stars distant 1".4., by instruments 

 which are the work of an unassisted, and alm_ost 

 neglected, American optician. 



Judging from the progress m^ade in his art, by 

 Mr. Holcomb, during the past year, the committee 

 look forward, with confident expectation, to the not 

 far distant period, when, should his health be spared, 

 the country will be in possession of a twenty feet re- 

 flector, of native workm.anship, rivalling the best 

 European instruments, and that, too, without the 

 patronage of any corporate institution, should all of 

 them be willing to waive the opportunity of sharing 

 with him the merit of such an enterprise. 



The committee have been led to enlarge upon this 

 subject, from a knowledge that one of our national 

 institutions has, within a few years, imported into the 

 country, at an expense of $2,500, a telescope which, 

 though excellent in its kind, is inferior to that exhibited 

 by Mr. Holcomb, which was made and mounted to 

 order for an individual in Georgia, at less than the 

 eighth part of the above m.entioned sum. It is not 

 probable that a twenty foot instrument from Mr. 

 Holcomb, would cost eight times as much as one of 

 the length of ten feet. 



The mode of mounting the instrument appears to 

 be original, and nothing can exceed it in simplicity, 

 or steadiness. Indeed, with a power of 900, no in- 

 convenience was perceived from resting with one 

 hand on the frame, and another on the tube, al- 

 though the same could not be done with the mounting 

 used by Mr. Holcomb last year, or with that of 

 common achromatics with a power of 200, without 

 serious inconvenience. 



PAPER 26: THREE 19TH-CENTURY AMERICAN TELESCOPE MAKERS 



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