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directed towards himself, and the photographer manipulating it and looking at him through it, he got excited, and with one blow of his trunk he smashed the apparatus, and was ready to deal a second blow at the photographer, when some of the staff of the menagerie rushed to his assistance, and succeeded in restoring the animal to his normally docile condition. On being assured that the elephant would now keep perfectly quiet, the photographer commenced his work again with another camera, and, after several attempts, succeeded in obtaining a good negative. People who essay to take pictures in a wild beast show will do well to provide themselves with a wrought-iron elephant-proof camera. The ordinary makes are too fragile.— Sportsman. Success OF the AMERICAN Eclipse Expedition.—Professor E. S. Holden, of the Washington Observatory of Madison, Wisconsin, with his party of observers, who were sent out by the United States Government to the Caroline Islands to make Observations on the total eclipse of the sun of May 6, has arrived at San Francisco in good health. Professor Holden reports that the weather on the day of the eclipse was favourable, and that a number of excellent photographs were taken showing good views of the corona. Some fine observations of the spectra were made. The supposed planet Vulcan was not, however, discovered. The party went from New York city to Lima, last March, thence in the United States sloop of war Hartford to the Caroline Islands. The duration of the eclipse was comparatively long, and opportunities for observation good. — Sclentijic American. The Luminosity of Non-Illuminating Gas Flames.—As the illuminating power of gaseous flames is known to be due to the presence of incandescent solid or even liquid particles, it has been customary to say that the feebly luminous flame of gases which do not contain such particles is the effect of the incandescence of the gas itself at a high temperature. Dr. Werner Siemens had an idea that pure gases, however highly heated, did not emit light; and he has recently carried out a series of experiments to determine this question. In order that an experiment of this nature should be decisive, the observed temperature should be higher than that produced by luminous combustion. Dr. Werner Siemens therefore had recourse to the regenerative furnace used by his brother, Friedrich Siemens, of Dresden, in the manufacture of hard glass. The furnace stands in a separate room, which can be made perfectly dark. In the walls of the furnace are two openings opposite each other, thus allowing free vision through. A heat of 1,500° or 2,000° C. (or beyond the melting temperature of steel) can easily be obtained. Before the sight-holes were placed a series of smoke-blackened screens, with central openings so proportioned to the holes in the furnace that the observer could look through the latter without receiving any rays from the heated walls. If, under these con ditions, dampers were closed, and all light excluded from the room, it was found that not the least light came to the eye from the highly-heated air in the furnace. For the success of the experiment it was necessary to avoid any combustion in the furnace, and then wait until the enclosed air was as free from dust as possible. Any flame in the furnace—even when not in the line of sight—or the least quantity of dust in it, illuminated the field of vision. As a result of these experiments, Dr. W. Siemens considers the view hitherto held, that highly-heated gases are self-luminous, is not correct. In the furnace were, in this instance, the products of the previous combustion of the fuel with atmospheric air ; or a mixture of oxygen, nitrogen, carbonic acid, and aqueous vapour. If only one of these gases had possessed the property of being self-luminous, the field of vision must have been always illuminated. The weak light of burning gases, wherein there is no separation of solid particles, cannot, therefore, be considered as a phenomenon of the glow of the gaseous products alone. It further occurred to Dr. W. Siemens as probable that heated gases do not emit heat rays. After again convincing himself and Dr. Herr Frohlich, of Dresden, that the heated gases were perfectly dark, Dr. W. Siemens’s thermopile experiments for the investigation of the other hypothesis failed. By the aid of a common lamp, how ever, it was found that heated gases do radiate some heat, but much less than some solid bodies at the same temperature. Dr. W. Siemens does not yet say what he believes to be the cause of the feeble light of so-called non-luminous gases.— Journal of Gas Lighting. Photographic Club.—The subject for discussion at the next meeting on July 11, will be the adjourned discussion on “The best lens for instantaneous landscapes, especially with regard to the angle desirable to be included.” o Gurresgondents. *,* We cannot undertake to return rejected communications. F. Gregory.—It is obviously impracticable for us to give you in this column such complete directions as you require; but we advise you to carefully study Mr. W. K. Burton’s “A. B. C. of Photography. Perhaps the light by which you work is not sufficiently safe. A SUBSCRIBER from 1863.—1. We have tried the formula you mention, but did not find it quite so satisfactory as the developer mixed in the old-fashioned way. 2. The first is citrate of soda, and the second is the protoxalate of iron (ferrous oxalate). Each of these salts can be obtained from a dealer in photographic chemicals. C. R. S.—Your experience corresponds with much of ours, and you must look on the case referred to as exceptional. W. A. C.—A rectangular satchel, made of leather sufficiently stiff to afford some protection to the camera, is usually made use of, and it is as well not only to have a division between the camera and the dark slides, but to leave room for lenses, focussing eye piece, &c. Your best way will be either to send the camera to a maker of photographic apparatus, and leave him to design the case ; or to make a rough model in cardboard, and to hand it over to a local saddler. JOSEPH Lewis.—Your suggestion is not a bad one, and we will see if we can carry it out. J. C. J.—1. An ordinary print on sensitive albumenized paper was referred to. 2. Cold water. We cannot give the exposure in minutes, as so many circumstances may cause it to vary. You may vary the method by inking the unsoaked plate as sug gested in a subsequent leader. This will give you a somewhat greater body of ink. H. T. W.—That you mention is, we believe, good value for the money. Russell Steel.—Write to Mr. England. T. R. Young.—1. Acid fumes would certainly tend to render it in soluble, but you can neutralize them by sprinkling a few drops of ammonia about the locality where you work. 2. The book is in German. Write again if any difficulty arises. E. J. Asser.—Many thanks for the block, which we shall probably use next week. R. Stewart.—Try Luckhardt’s medium, as given in the Formulary last week. Anxious.—They are often due to traces of greasy matter in the gelatine. S. TIMBERT.—1. It is quite impossible for us to form an opinion in such a case, unless after a very careful investigation of all the details. 2. The metal need not be more than one-eighth of an inch thick in ordinary cases. 3. Not unless a moderatpro) r - tion of alcohol is added. Beginner.—For such work, patent plate glass should always be used, as want of flatness will prevent that close contact upon which sharpness of definition depends. Manchester.—1. The sulphate is hardly soluble enough, so wo would advise you not to make any change. 2. Light petroleum or benzoline will answer very well. 3. Boil it in water until it becomes sufficiently soft. 4. It is due to the action of heat. F. T. Simpson.—1. According to Pizzighelli and Hubl, it is easy to influence the tone by varying the nature of the sizing material: a gelatinous preparation yielding a bluish-black tint, and a starch preparation yielding a brown-black tint. See page 128 of the Year-Book. 2. We do not understand your objections to gela tine as a mountant; explain your difficulties more fully. Will iam Purchase.—You dry the films at far too high a tempera ture. M. R. F.—You should certainly focus with an eye-piece in such a case, and if you render a small portion of the focussing screen transparent by means of a touch of varnish, you will find it easier to work with exactness. Amateur.—1. Few use it now, the old system having proved more convenient. 2. A cold saturated solution. 3. It is an indication that the whole of the silver is precipitated. 4. You might try the experiment, but unless you dry the film very completely, it 18 almost sure to undergo decomposition in a few days. Cambridge.—There is a special knife sold for the purpose, and 1 is probable that you will be able to obtain one from Hughes and Kimber, of East Harding Street, London. , John B .—It appears to us that yours is a case in which mu is to be said on each side; and it is probable that, if brought into court, it would lead to very prolonged litigation. How would 1 be for you to yield as regards the 4th aad 6th points, in order i see if the other party is inclined to come to terms ? . Beginner.—No wonder, as such a dark room as you describe is oy no means safe for gelatine work. One thickness of cherry iaor over the window will probably put matters right. Alex. Thomas.—As the process is not worked commercla-A. present, you will have some difficulty. Try some of the ° stock-houses.