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234 THE PHOTOGRAPHIC NEWS. [MARCH 20, 1891. to a forked joint secured to the other shaft, and with a movable cross-bar similar to the one before described. By connecting the shafts with a coupling constructed as described, they can be rotated without bevel wheels, with this advantage, the coupling will adapt itself, connect and rotate shafts placed at any angle within a range of 90° or thereabouts, whereas bevel wheels have to be made to suit the angle of the two shafts, Eorresponence. THE LIVERPOOL INTERNATIONAL PHOTOGRAPHIC EXHIBITION. Sib,—The reference to the portraits of Professor Herkomer is somewhat in error ; all are the work of Mr. F. Downer. I am aware this report was some oversight on the part of The Liverpool Daily Post, and for which your publication is not re sponsible. I thank you for the full and friendly words you have published. You will be glad to know that everything goes on most satisfactorily; 1,600 visitors on Saturday. Judges awards meet confirmation in every case, I think. T. S. Mayne, Hon. Seo. THE NEW YORK MAY EXHIBITION. Sir,—-It will be of interest, perhaps, to all amateurs and other photographers to know that arrangements are now in progress for a very large, select, and important exhibition of photographs, including specimens of the best foreign work, to be held in New York at the Fifth Avenue Art Galleries, between 34th and 35th Streets, May 25th to June 6th, under the auspices of the Society of Amateur Photographers of New York. It will be the fourth of the joint series of exhibitions undertaken with the aid of the Photographic Society of Philadelphia and the Boston Camera Club. The prospectus and entry forms have already been sent out, and the judges selected are, Thomas Moran, Will H. Low, and Edward Bierstadt—men well known in the respective branches of art which they represent. Medals are to be awarded instead of diplomas, the number being limited to twenty-five. Exhibitions of slides will be held four nights during each week, and in a separate room there will be an exhibit of new and novel apparatus. Foreign exhibitors may send pictures unmounted, which will be mounted and framed by the committee. Exhibits should be sent to the Galleries by May 11th to ensure attention. The committee prefers that the very choicest work be sent, rather than a large quantity of ordinary pictures. Exhibits are invited from all photographers, and, when received, will be carefully attented to. Entry forms will be sent on application, and all correspondence should be addressed to— F. C. Beach, Chairman of Committee of Arrangements, 113, West 33th Street, New York. FLUOROGRAPHY.—Fluorography is, according to a contem porary, a process of transferring lithographic or phototypie prints to glass by means of fluorated ink, which, in contact with sulphuric acid, disengages hydrofluoric acid, which eats into the glass. The phototype is inked with the following compound :— Soap Glycerine Tallow 50 grammes 200 „ 50 Water 100 Borax ... ... ... ... 25 Fluorspar 50 Lampblack 15 Negatives are taken and transferred to the glass. The latter is surrounded with a border of wax and covered with sulphuric acid of a density of 64° or 65° Beaume. After fifteen or twenty minutes the acid is poured off and the glass is washed with water and cleaned with a solution of potassa, then washed with water again, and dried with a cloth. Proceedngs of Soctettes. The Photographic Society of Ireland. A meeting was held at the Rooms, 15, Dawson Street, Dub lin, on the 13 th inst., when the chair was occupied by Mr. Herbert Bewley. A discussion on “ Hand-Cameras ” was introduced by Mr. J. White, who exhibited a number of different makes, but stated his preference for Bouch’s “Eureka,” the camera with which he had taken all his prize pictures. He stated that portability and simplicity were, in his opinion, the main features to be aimed at in the construction of a hand-camera. A large number of members exhibited different makes of hand-cameras, a great many of such were home-made. After the exhibition of hand-cameras ; a number of slides, the works of the members, were put through the lantern. A “ Parvenu ” flash-lamp was presented by Mr. Hedley for the use of members. The Lantern Society. March 9th.—Mr. E. W. Maunder on “Photography as Applied to Astronomy.” Mr. Maunder commenced by dealing with solar photography, the sun having, he said, been the first celestial object which was photographed for scientific purposes. Soon after the discovery of the Daguerreotype process, photographs were taken of the moon, and also of some stellar groups, but these views did not serve any scientific purpose, and it is from the sytematic use of the photo-heliograph for obtaining photographic records of the state of the solar surface that the application of photo graphy to astronomical purposes may be said to date. Mr. Maunder next spoke of the first photo-heliograph erected at Kew, and described in detail the later instrument now used at Greenwich, the work done by the instrument being illustrated by a series of slides showing portions of the solar surface. Other views were also exhibited prepared from the beautiful photographs taken by M. Janssen at Meudon, these being, as Mr. Maunder remarked, the finest solar photographs yet pro duced, showing as they do most admirably the details of the structure of the surface of the sun and the facula?. While dealing with solar photography, Mr. Maunder also pointed out the strong grounds for connecting the periods of maximum solar disturbance, as marked by the frequency and extent of sunspots with terrestrial magnetic disturbances, and he farther alluded to the manner in which the periods of maxima and minima were marked by variations in the latitude of spots occurring. The next portion of the subject treated was the application of photography to the observation of total solar eclipses, the instruments used being described, and a number of photographs shown illustrating the structure of the corona as seen at recent eclipses. Leaving the sun, Mr. Maunder next proceeded to treat of the photography of the planets, illustrating his remarks by slides of Jupiter and Saturn taken at the Lick observatory, and by Professor Picker ing, of Harvard. The task of photographing a planet was, he remarked, one of great difficulty, inasmuch as the very moderate light available did not admit of instantaneous ex posures such as sufficed in the case of the sun, while the rapid rotations of Jupiter and Saturn on their axes prevented recourse being had to the long exposures which could be employed when photographing fixed stars. Altogether, up to the present time, although remarkable progress had been made, photographs of the planets left much to be desired, and could not compare favourably with the records obtained by skilful draughtsmen. In illustration of this, there were thrown upon the screen reproductions of a number of the best drawings of the planets of which direct photographs had been shown. Dealing next with stellar photography and photographs of nebula?, Mr. Maunder remarked that in these departments photography left all records founded on visual observations far behind ; in fact, the details of structure of nebule, as shown by the magnificent photographs of Common and Roberts, had been a complete revelation, and had resulted in an extension of our knowledge of such bodies, the value of which it was difficult to over-
