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SCIENCE-GOSSIP. 



NEW HAND BINOCULAR TELESCOPES. 



'""PHESE remarkable instruments have been 

 greatly improved, and produced for the 

 English market by the Carl Zeiss Company, of 

 Jena. Before describing the instruments it may 

 be well to say something about the manufacturers, 

 which will be found of more than passing interest. 

 The Carl Zeiss Optical Works are probably the 

 the most important of their kind in the world and 

 are quite exceptional in their constitution. The 



Fig. i. 



firm was established some years ago by a skilled 

 workman whose name it bears. He is no longer 

 living, neither is any member of his family connected 

 with the factory. Jena is a university city in Saxe- 

 Vv'eimar-Eisenach, one of the Thuringian states of 

 the German Empire. When Zeiss began to make 

 his way he found the necessity of the association 

 of some scientific adviser, and was fortunate enough 

 to obtain in that capacity the well-known Professor 

 Abbe. In consequence of the rule that only the 

 very best possible work should leave the factory, 

 the business grew with great rapidity. 



This institution is now a public trust, with the 

 Duke of Saxe-Weimar as Chairman. By public 

 trust it must not be supposed that a public company 

 in the ordinary sense is meant, for the profits 

 annually earned, which are large, do not benefit 

 individuals in the sense of shareholders. The pay- 

 ment of wages to the ordinary staff is liberal, 

 the scientific staff receiving no less a sum than 

 /5,ooo annually. In this division is still included 

 Professor Abbe, with whom is associated Dr. 

 Czapski, as advisers in the optical department, 

 and Dr. Pulfrich in a like capacity on instru- 

 ments for physical research, whilst Dr. Rudolph 

 advises on photographic objectives ; Mr. Fischer 

 being general business manager. To return to the 

 question of the profits, they are divided between 

 old-age pensions for the workmen and grants for 

 the encouragement of scientific research. The 

 University of Jena receives a portion of these 

 latter grants and more than one Englishman has 

 participated, if not actually in money, in the form 

 of scientific instruments. The invested pension 

 fund now exceeds £250,000. 



Some idea of the magnitude of the Carl Zeiss 

 Works may be gathered from the fact that it 

 requires three hours to pass through the various 

 wings and departments, without leaving much 

 leisure for inspection of details. Upwards of 500 

 workpeople are employed, a curious feature being 

 that there is no difficulty in obtaining skilled 

 workers in metals, but the optical hands have to 

 be trained within the works from boyhood. In 

 consequence of the frequent 

 addition of extra rooms to the 

 factory difficulty in trans- 

 mitting the power from a 

 central steam engine was 

 from time to time increas- 

 ing, the loss of power being 

 more than fort)" per cent. 

 This difficulty has been 

 overcome by making the 

 steam-engines drive large 

 electric dynamos, which are 

 connected to separate motors under each work- 

 man's bench, the loss has thus been reduced to 

 eighteen per cent. 



We figure two of the Zeiss instruments, fig. 1 

 being the Hand Binocular Telescope, and fig. 2 

 the Field Glass on the same principle. The 

 telescope was originally designed by an Italian 

 engineer, named Porro, for military purposes, but 

 has been much improved by Carl Zeiss. By the 

 aid of this instrument an officer in the trenches can 

 see what is going on with perfect accuracy, without 

 exposing his head above the edge of the trench. In 

 the same way a naturalist is able to watch the 

 habits of a bird or other animal from behind a rock, 

 a wall, or a bush, without being seen. This is 

 accomplished in consequence of the apertures for 

 the lenses being in the sides of the metal terminals 



and not at the ends, as is usual. Thus by spreading 

 out the two tubes from the vertical position to one 

 that is horizontal, an observer may stand behind a 

 tree and see round it, without being observed by 

 the object under examination. 



This effect is obtained by an ingenious arrange- 

 ment of prisms, which is fully explained and 

 illustrated in the specification of the patent which 

 was completed last 3 - ear, It would take up too 



