Page:Popular Science Monthly Volume 90.djvu/852

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��Popular Science Monthly

Six Acres of

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��Washing the negatives in clear water after the develop- ing and fixing process. Two-hundred-foot lengths are handled at one time and afterward pieced together

��film an additional bath is required to clear the high lights and sharpen the detail; otherwise the method is the same as for the negative.

The two-hundred-foot lengths of film are then wound on reels, five lengths being cemented together to produce the standard length of one thousand feet.

In every picture "titles" and "sub- titles" are required to explain the action. These are photographed on the film when the other parts of the picture have been taken. The piecing together of the vari- ous sections of film requires the exercise of great care for never are the scenes of a play filmed from begin- ning to end exactly as they are planned by the scenario writer. If five different episodes take place in a d rawin g room, they will all be photographed at once, even though hun- dreds of feet of landscape film may ulti- mately in- tervene be- tween them.

���A typical coal boat. It is twenty-six feet wide and travels abreast of eleven others and a steamer

��Coal Floating on the Mississippi

NLY in the United States can such a sight be seen as six acres of coal floating down a river as a single unit. This is the area of coal boats which the well- known stern-wheel steamer Sprague is capable of handling as a single tow. Four across-stream rows of twelve boats each, make up the principal part. Back of the fourth row, however, eight boats find places together with two barges. Hence, there are fifty-six boats and two barges in the big fleet. The Sprague has her nose shoved in at the center of the fifth row. The fifty-nine vessels are lashed securely together by lines which run from boat to boat. Al- though the Sprague can push the fleet ahead, her chief duty is to hold back the load.

This great amount of coal is handled by a relatively small total of horsepower because the current of the onflowing river supplies a large part of the requisite energy.

The big efficient stern wheel of the Sprague stands forty feet high. When bends in the river have to be rounded, it controls the boats by suitable backing move- ments. If the steamer itself goes aground, this big stern wheel ma}^ be utilized to drive water in under the stern of the

boat to sup- ply a kind of miniature flood tide. When the sand bars, swift current and tortuous course down the Missis- sippi River, where the Sprague is principally engaged, are taken into consi dera- tion, it will be granted per- haps that the captain has a responsible, difficult task.

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