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INFORMATION, ART, SCIENCE, MECHANICS, CHEMISTRY, AND MANUFACTURES. A WEEKLY JOURNAL OF PRACTICAL Vol. XXX.-No. 11. ] ['3 per Annum, [NEW SI!:RIES.j NEW YORK, MARCH 14, 1874. ADVANCE. NEW AND GIGANTIC TELESCOPE. nicest engineering skill. In brief, it may be safely asserted tbe exact form necessary. But little labor, comparatively Among the many ideas which have been elicited by the that a metallic mirror, of the large size above noted. suppos­ speaking, will here be required, as an approximateIN or very discussion in these columns regarding a gigantic or " million ing it. could be successfully constructed, would, from its great nearly true curve will, it is believed, be taken by the glass dollar " telescope, we bave recently had submitted to our weight but far more on account of its conse'luent flexure,be in fitting itself to the mold. The reflecting face is, lastly, examination one which seems to us quite novel, ingenious, practically useless. silvered by Dr. Draper's process, a solution of Rochelle and. although untried, not unpractical. It is a scheme for Mr. Daniel C. Chapman, of tl>is city, who is the originator salts and nitrate of silver being applied, which very quick­ a huge instrument, to be built on either the Gregorian or of the plan we are about to describe, suggests both a mod., ly dllposits a fine uniform metallic surface. It will be Cassegrainian system, in which the image is firstreceived on of making a mirror of light weight, and also a method of noted that the inventor thus obtains a reflector of light a large parabolic mirror located in a position diametrically supporting the same. The reflector, he says, may be con­ plaster and glass, the weight of which is necessarily quite opposite to the objective in a refracting telescope, thence re­ structed of glass. A mold of clay, metal, or cement, of the small. flected back to a secondary mirror, which, in accordancewith required .hape, is carefully formed and placed in a suitable Next, for its suspension, and this will be rendered clear the respective systems, is either concave or convex, nnd by furnace, cavity upward. Over the latter a huge plate of glass by the large engraving on our front page: On the rear of the last re·reflected to the eyepiece, the tube of which passes is disposed, and the heat applied. At a certain temperature, the plaster backing are made a number of projections, ar­ through an orifice in the center of the large glass. It is the glass begins to Boften, and in such state may be bent, ranged with sockets to receive the ends of any number of hardly requisite to explain the immense labor and, in fact, fitted into tbe mold, and subsequently annealed. The whole braces. Tbe lat:er are of wood, strong and well seasoned, almost insuperable difficulties which would be encountered is then removed and placed on a plane. The glass is taken and covered with some preserving material. These, ex­ in constructing a reflector of the proposed size-ten or fifteen from its bed, disposed convex side up, and a backing of ce­ tending from various points on the back, meet at the cen­ feet in diameter-of metal, and mounting the same. The ment or plaster, tbe composition of wbich is previously de­ ter of a huge copper sphere, which incloses the entire ap. great mirror in the telescope in Melbourne, Australia, though termined by experiment so tbat it shall bave the same co­ paratus except the mirror, and tben, intersecting, spread but 3'8 feet in diameter and weighing 3,498 pounds, required efficient of expansion as the glass, is applied, to several inch. again to abut against the interior periphery of the globe. 1,270 hours of continuous labor to bring it into the last pol­ es in thickness. The mirror is next inverted, placed on a The mode of arranging these stages is, of course, a matter ishing stage, while its adjustment and mounting exacted the turning table, and carefully ground or finished within, into of engineering detail, and will depend greatly upon 10ebl NEW AND GIGANTIC TELE3COPE. DESIGNED BY DANIEL C. CHAPMAN. © 1874 SCIENTIFIC AMERICAN, INC 160 [MARCH 14. 1874. circumstances. The shell of the sphere comes, as shown monuments which attest the �kill and magnificence of the baits as are offered by these swindling agencies. We are in the engraving, jU8t to the edge of the mirror, but. has Ineal!. There are also, as at Tiahuanaco and Silust.ani, the perfectly well aware that it is about as har.d to show an in. nothing to do with its support, the braces being solely for remains of burial towers and palaces, which antedate the ventor that his device, when once patented, is of small utility this purpose. The secondary mirror is held by two stays, crusades, and are therefore pre.incarial. and value, as to convince a mother that her baby is ugly, which ex tend from the circumference of the reflector·and Lake 'J'iticaca is about the size of our Ontario, IIhallow on and both individuals usually resent the imputation in about meet at a calculated distance from the same. It is not neces­ the west and north, deep towards the east and south. The the same manner. It is these very inventors, however, who, sary that the reflector be placed at the surface of the globe, eastern or Bolivian shore, being hacked by the lofty range of having exhausted every plan to dispose of their rights, snap but it may be placed at or near the center, leaving an opening Sorata, is very high and precipitous. The lake never freezes at the allurements artfully held out to them. and of course of the same size in the globe, with perpendicular sides, thus over, although the temperature of Puna is often 18° at sun­ are fleeced. The world gives little sympathy, for it laughs requiring little or no counterpoise. The standards and stays rise. Two little steamers of 100 tuns each do a triflingbusi­ at their verdancy in being so readily deceived ; but when the holding the small mirror may be attached to the extreme ness. Steam is generated by llama dung, the only fuel of trials, the labor, and expense, which these men incur to carry external surface of the globe, thus giving a larger base and the country ; for there are no trees ",ithin 150 miles. The out their cherished ideas, be reflected upon, the subject be­ greater steadiness. The stays toward the poles are so ar· steltmers actually cost their weight in silver; for their trims· comes more one for pit.y than for derision. ranged that the lower one is detache:l when nearing the portation (in pieces) from the coast cost as much as the origi­ We would once more warn the people against not only t.he horizon, in case it shoull be desirable. By this method nal price. A steamboat company has just asked from attempts to defraud, above exposed, but against every other there is nothing, as far as we can now see, to prevent the suc­ Bolivia the exclusive privilege of navigating Titicaca and the they may receive that even appears of similar nature, par cessful constructing and using of a telescope of very large size. Rio Desaguadero to Lago Pampa, with a guaranty of six ticularly against specious parties who, for a certain sum, Through the center of the large glass is made an opening,and per cent cost on the capital and a share in all new mines agree to sell a patent and advertise it.1nsome patent journal n this is a telescope tube, suitably jointed and terminating discovered. or other obscure circular or sheet. It is very rarely that n an eyepiece within the globe at the observer's seat. The sit­ Professor Orton, the latest traveler in that region, calls these men ever effect a sale ; and if they be swindlers, they nation of the latter is clearly shown in the illustration, and attention to the fact that Lake Titicaca is not so high as dare not announce the fact, if they have done so. Indeed, if it is suitably supported so as to be always vertical. By usually given in geographical works by about 300 feet. Its any of our readers desire to prove for themselves the genu­ this arrangement the observer is constantly located in the true attribute is 12,493 feet, and in the dry season it is four ineness of the offers of their correspondents, they have only right position ; and by placing a partition of some non-con feet less. This fact has been revealed by the CQp.�ecutive to write to the latter for the nalDes of reputable persons ducting material between him and the backing of the re­ levelings made in building the Arequipa railway just fin. whose patents have been sold through their agency ; and if flector, so as to leave an intermediate space of four or five ished, which reaches from the Pacific to Lake Titicaca. any be returl!ed personal investigation will soon determine inches, a warm room to work in may be gained, and a means The road rises from the sea to Arequipa,7,550 feet; thence to the question of authenticity. of keeping the braces dry provided. the summit, 14,660 feet ; and then descends over 2,000 feet, -------------.�.. .••� -- ----------- The great sphere pivots in a ring, the axis of which is in­ to Puno on the west shore of tbe lake,a distance by the track FAILURE OF THE NEW TELEGRAPH LINE BETWEEN clined to point to the pole, and is pivoted at one side in the of 325 miles from the ocean.

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