Stories of Inventors: The Adventures of Inventors and Engineers

by Russell Doubleday

It was 4:45 in the afternoon. The photographer was all activity. The minute the race was over the motor above the great camera was stopped and the box was opened. From its dark interior another box about six inches square and two inches deep was taken: this box contained the record of the race, on a narrow strip of film two hundred and fifty feet long, the latent image of thousands of separate pictures.

Then began another race against time, for it was necessary to take that long ribbon across the city of Brooklyn, over the Bridge, across New York, over the North River by ferry to Hoboken on the Jersey side, develop, fix, and dry the two-hundred-and-fifty-foot-long film-negative, make a positive or reversed print on another two-hundred-and-fifty-foot film, carry it through the same photographic process, and show the spirited scene on the stereopticon screen of a metropolitan theatre the same evening.

That evening a great audience in the dark interior of a New York theatre sat watching a white sheet stretched across the stage; suddenly its white expanse grew dark, and against the background appeared "The Suburban, run this afternoon at 4:45 at Sheepshead Bay track; won by Alcedo, in 2 minutes 5 3-5 seconds."

Then appeared on the screen the picture of the scene that the thousands had travelled far to see that same afternoon. There were the wide, smooth track, the tower-like judges' stand, the oval turf of the inner field, and as the audience looked the starter moved his arm, and the rank of horses, life-size and quivering with excitement, shot forth. From beginning to end the great struggle was shown to the people seated comfortably in the city playhouse, several miles from the track where the race was run, just two hours and fifteen minutes after the winning horse dashed past the judges' stand. Every detail was reproduced; every movement of horses and jockeys, even the clouds of dust that rose from the hoof-beats, appeared clearly on the screen. And the audience rose gradually to their feet, straining forward to catch every movement, thrilled with excitement as were the mighty crowds at the actual race.

To produce the effect that made the people in the theatre forget their surroundings and feel as if they were actually overlooking the race-track itself, about five thousand separate photographs were shown.

It was discovered long ago that if a series of pictures, each of which showed a difference in the position of the legs of a man running, for instance, was passed quickly before the eye so that the space between the pictures would be screened, the figure would apparently move. The eyes retain the image they see for a fraction of a second, and if a new image carrying the movement a little farther along is presented in the same place, the eyes are deceived so that the object apparently actually moves. An ingenious toy called the zoltrope, which was based on this optical illusion, was made long before Edison invented the vitascope, Herman Caster the biograph and mutoscope, or the Lumiere brothers in France devised the cinematograph. All these different moving-picture machines work on the same principle, differing only in their mechanism.

A moving-picture machine is really a rapid-fire repeating camera provided with a lens allowing of a very quick exposure. Internal mechanism, operated by a hand-crank or electric motor, moves the unexposed film into position behind the lens and also opens and closes the shutter at just the proper moment. The same machinery feeds down a fresh section of the ribbon-like film into position and coils the exposed portion in a dark box, just as the film of a kodak is rolled off one spool and, after exposure, is wound up on another. The film used in the biograph when taking the Suburban was two and three-fourth inches wide and several hundred feet long; about forty exposures were made per second, and for each exposure the film had to come to a dead stop before the lens and then the shutter was opened, the light admitted for about one three-hundredth of a second, the shutter closed, and a new section of film moved into place, while the exposed portion was wound upon a spool in a light-tight box. The long, flexible film is perforated along both edges, and these perforations fit over toothed wheels which guide it down to the lens; the holes in the celluloid strip are also used by the feeding mechanism. In order that the interval between the pictures shall always be the same, the film must be held firmly in each position in turn; the perforations and toothed mechanism accomplish this perfectly.

In taking the picture of the Suburban race almost five thousand separate negatives (all on one strip of film, however) were made during the two minutes five and three-fifths seconds the race was being run. Each negative was perfectly clear, and each was different, though if one negative was compared to its neighbour scarcely any variance would be noted.

After the film has been exposed, the light-tight box containing it is taken out of the camera and taken to a gigantic dark-room, where it is wound on a great reel and developed, just as the image on a kodak film is brought out. The reel is hung by its axle over a great trough containing gallons of developer, so that the film wound upon it is submerged; and as the reel is revolved all of the sensitised surface is exposed to the action of the chemicals and gradually the latent pictures are developed. After the development has gone far enough, the reel, still carrying the film, is dipped in clean water and washed, and then a dip in a similar bath of clearing-and-fixing solution makes the negatives permanent—followed by a final washing in clean water. It is simply developing on a grand scale, thousands of separate pictures on hundreds of feet of film being developed at once.