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Archives of an email list on the history of binoculars. - page 11 / 150





11 / 150

A transcription of the two articles:

English Mechanic, vol. 60, #1558, Feb. 1, 1895, p546:

  The New Binoculars.  It might interest your readers to know that, since my letter on "Zeiss' New Patent Binoculars" appeared in the "E.M." on Nov. 30th,  1894, a friend has kindly sent me for examination a monocular telescope constructed on precisely the same plan - viz, an astronomical telescope whose image was erected by two right-angled prisms.  The maker's name was J. G. Hofmann, of Paris, and the telescope was supposed to be three-quarters of a century old.  The lenses of the Huyghenian eyepiece were separable by a spiral adjustment, which enabled the power to be varied from 10 to 15 diams.  I have also been informed that Mr. Ahrens made a binocular on the same principle some twenty-five years ago.     Edward M. Nelson."

English Mechanic, vol. 61, #1561, Feb. 22, 1895, p13:

  The New Binoculars.  In your issue of Feb. 1, p546, a further short notice by Dr. Nelson appeared respecting Zeiss' new patent binoculars, following his description and criticism in No. 1549, of Nov. 30, 1894.  In this second notice Dr. Nelson states that a friend had sent him a monocular telescope constructed on precisely the same plan as Zeiss' binoculars.  The maker's name was F.G. Hofmann, of Paris, and the instrument was supposed to be three-quarters of a century old.  With reference to this, it may be of interest to state that Messrs. Zeiss very distinctly declare, on the first page of their prospectus of the new telescopes, that the principle of these telescopes -  viz., the use and arrangement of the prisms for total reflection and for the erection of the image -  was not their conception, but was first invented by Porro.  This is stated in a still more emphatic manner in the patent specifications - for instance, in the English Patent Specification No. 7942, from page 1, line 31, to page 3, line 4.  This specification, further, most clearly shows the novelty of construction of the Zeiss telescope, and where it differs from those of Porro.  It would, therefore, have been an easy thing for Mr. Nelson to have obtained full information about this matter.

  With reference to the instrument manufactured by Mr. Hofmann, it might be of interest to your readers to learn that the latter was at one time a foreman to Mr. Porro.  He afterwards established himself in business, and he obtained a considerable reputation for his manufacture of spectroscopes.  He also made Porro telescopes of superior construction, and offered them for sale.  This, however, was not three quarters of a century ago, but about 25 years since - i.e., about one quarter of a century.  I was not aware that Mr. H. Ahrens had also manufactured straight-sided telescopes with a system of reflecting prisms.  The principle of the Porro telescope, has been, however, repeatedly invented by others since Porro.  This is fully explained in a report by Dr. Czapski on these telescopes, which will be published in a few days.   --J.W. Measure.


Subject: Kelsey Hayes.

I asked about a binocular marked 'Kelsey Hayes'.

From: WIta057@___m

Kelsey- Hayes makes automobile brake systems and components.  I believe they are now part of TRW.  Aloha, Wayne.

From: "Preston Cook" <sdp45@___ink.net>

This company has been active for many years in the automotive industry.  Their primary products are brake system and suspension components.

Preston Cook


Subject: Image Stabilized Binoculars

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