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ers of suitable size, I proceeded to build withdrawing the kites. them.

The lifting of an eight to ten pound outfit into the air is but a matter of using a sufficient number of parakites to produce the needed lifting energy, indicated by the number of pounds pull on the dynamometer at the earth, but it was economy of energy and labor to produce a camera which would reduce the labor to the minimum. The

details of my first camera

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ascertained ratio
being eight
one pound
this out-
re-

The of pull pounds to of weight. fit therefore quires a pull of about forty pounds; but, as that is the minimum, fif

ty pounds

pull has been

found to

14

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gaff and other details, weighs as follows:

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lbs. ozs.

3 ΙΟ

5

I

afford a steadier support. My latest camera, of the same capacity as the above, is made of eight united layers of heavy buff 7 wrapping paper, formed on a mold. The camera is held pendent from the trolley I by aluminum telescoped tubing, by which the lens may be turned in any direction. The trolley is also of aluminum. This camera loaded with two 62 × 81⁄2 glass plates, with all accessories, weighs just three pounds. The illustration [p. 625] shows it in the air ready to be snapped. The view over New York City was taken by this apparatus, flown from the roof of

3

4 15

By the use of the trolley the camera
can be sent out and brought back,
and a number of ex-
posures made without

Reel and Spools of Twine of Various Sizes.

the New York University, Washington Square [p. 622].

The lens used in both cameras was made by Alvan G. Clark. Its details are: rapid rectilinear angle. fifty-five degrees; symmetrical wide angle, ninety five degrees; ize, 61⁄2 x 81⁄2 inches; diameter, 11⁄2 inch; back focus, 1038 inches; equivalent focus, 11 inches.

The spool on the reel contains 1,250 feet of long staple Irish flax twine, tested to a breaking strain of one hundred pounds. One revolution of the large gear wheel winds three feet of twine.

The triplex shutter, with rotary diaphragm, in which aluminum was used as far as practicable and serviceable, was made specially for the

purpose, under the supervision of Mr. George E. Henshaw, an expert amateur photographer of New York City.

A cam-like bit of wood, weighing four grains troy, is placed over the junction of the spring with the trigger, when set ready for an exposure in the air. The tripping of the trigger by a thread from the operator on the ground tips and upsets this cam, to which is pendant just below the camera a bright red celluloid sphere two inches in diameter. This ball, attached to a thread, drops a length of four feet, and is readily discerned at great altitudes and indicates that

an exposure has been made. The shutter

cannot be

snapped

without

the ball drop

ping; the ball cannot be dropped without the shutter having been snapped both open and shut.

Some of the views taken with this camera cover the width of the lower part of the business portion of New York City, and from Washington Square southward to Staten Island in the Harbor of New York.

The unique conditions under which aërial photographs are taken present special difficulties and new problems that can be overcome only by repeated trials. High up in the air the camera is completely immersed in an intensity of light that searches out its every cranny, and it will be often found that a box

trees and other objects will show as the eye is accustomed to see them. If in taking a picture directly downward the swing-back be adjusted at a large angle of divergence from the camera's line of vision, parts of the resulting picture will be out of focus.

The effect of

perspective,

so familiarly called to mind by the converging tracks of a railroad, is evident in the horizontal

lines of an aërial picture and also in the apparent tendency, when the photograph is taken directly downward, of the walls of high buildings to come together at the bottom. There is really a double perspective somewhat confusing to the eye.

Distortions so familiar to everyone who has used a fixed camera can be minimized by directing the camera at an acute angle with the plane of the

landscape, and, of course, the greater the altitude at which an exposure is made the farther away will be the foreground.

The smoky and dusty haze that overhangs our great cities is a pronounced hindrance in successful picture-taking, especially in the early part of the day when the sunlight is deflected as if

that has long been thought Camera Suspended from a Tele- passing edgewise through a

scoping Aluminum Rod At-
tached to Trolley.

absolutely light-tight is surprisingly and disappointingly vulnerable. Foggy plates and those that reveal "ghosts" of a most weird and unaccountable character show that "absolutely light-tight" applies to ordinary conditions only.

By using a camera with a swing-back adjusted so that the plate will be practically parallel with the vertical objects in the view, the landscape in the picture will appear horizontal, and church-spires, tall buildings,

VOL. XXII.-65

plate of glass, and in the late afternoon the lights and shadows are unpleasantly emphasized. The growing interest in and popularity of kite-flying, and the wide attention which new experiments with kites as a lifting power attracts, show plainly that it will be a matter of only a short time when the camera will be a part of the equipment of every kite-fleet. Aerial photographs may become as common as the snap-shots that now confront us on all sides.

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PHOTOGRAPHY has been for a number of years a most valuable help to astronomers in mapping the stars and making records of other celestial phenomena, and of late many interesting applications of the camera have been made in taking pictures of all sorts of luminous objects. Remarkable and realistic photographs of firework displays, foundry and rolling-mill interiors, blast furnaces, and other weirdly picturesque scenes have been accomplished, the best of them with the aid of the flash-light. The nonluminous details are taken with the flash, while fires and other brilliant lights make their own impressions.

Moonlight effects in photographs have long been admired by the uninitiated, and fully appreciated by both amateur and professional photographers for their beauty, and many plates, too, have been spoiled by snap-shotters who have accepted moonlight as the real illuminator of these views, and accordingly focused directly on this beautiful orb of night. Moonlights with the moon herself in evidence are really sun photographs, that is, pictures taken with a

rapid exposure, the camera pointed toward the sun generally in the late afternoon or early morning and with clouds between the lens and the direct rays.

Many charming so-called night-pictures are taken by making two exposures, a short one in the rapidly diminishing afternoon sunlight, to get an impression of buildings and other dark objects, and another longer one after dark to print in the gas and electric lights that line the long street or mark out the roads and winding pathways of a city park.

It is only within the past two or three years, however, that actual night-photographs have been attempted with any considerable degree of success. Mr. W. A. Fraser, of the New York Camera Club, especially noted for his beautiful lantern slides, following the lead of Mr. Paul Martin of London, has succeeded in taking a number of charming moonlight views by the moon's diffused light, not looking her in the face, with an exposure of ten minutes; and some remarkable park and street scenes on snowy and rainy nights show, with sur

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Photographed by Alfred Stieglitz. Taken at 9 P.M., in January, 1897. Time of exposure fifty seconds.

prising distinctness and truth, very picturesque and interesting after-dark aspects of New York.

Great care must be taken to have the camera-one with a tripod is essentialsolidly planted, and a watch must be kept to prevent the lights of any passing vehicle or belated bicycler from entering the field of vision. Moving objects not carrying lights make no impression. Mr. Fraser uses a double non-halation plate, which he backs as a further precaution. Halation (halo plus ation) is the milky-way-like haze so often seen in plates that have been exposed with the camera pointed toward a window or other direct source of light, and is caused by light being reflected from the back of the plate itself. Halation bothered photographers for a long time and has been the occasion of much learned discussion regarding the mysterious action of light. To prevent it, specially prepared plates are used having a double coating of the sensitive emulsion-one slow, the other fast. Backing is covering the back of the plate with some opaque substance; asphaltum,

or sheets of brown carbon tissue paper are often used. Where there are only gas-lights in the view the exposure is from eight to ten minutes; with electric-lights-those only which are enclosed in opal shades can be successfully included-from two and a half to three and a half minutes.

Mr. Alfred Stieglitz, another amateur and member of the Camera Club, whose notably artistic photographs have attracted attention and won many medals both in this country and in Europe, has also been experimenting for the past year with night-pictures. Realizing how much more interesting such scenes could be made by the introduction of a human element, Mr. Stieglitz has made a number of views with figures in them with an exposure of less than a minute. With regard to efforts to entirely eliminate halation, he uses non-halation plates, but without the backing, saying justly enough that a certain degree of halation naturally belongs to these night-pictures, especially when taken as he prefers to take them— during a storm. Everyone has observed. the fuzzy globes of light that surround a

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