Page:Popular Science Monthly Volume 91.djvu/385

This page needs to be proofread.


Popular Science Monthly

��369

��Target Practice with the Smaller Coast Defence Guns

WHEN practic- ing with the smaller land defence guns, the United States army often uses a self-propelling target which is im- provised by the handy men about the fort. The target is carried far out to sea by a launch; there it is set going at a speed of from eight to ten miles an hour, and the guns begin their maltreat- ing of it in true American fashion!

While these tar- gets are the simplest sort of craft, they afford about the best type of target known. Two pon- toons fourteen feet long and which stick only a few inches

���This Red Cross flag that adorns a New York city department store measures 100x75 feet

��above the water, carry a marking flag. Usually, both pontoons are armored with quarter-inch boiler-plate, which is covered with gray target cloth. One of the pontoons carries the small " motor-boat engine. By means of its rudders, the craft can be made to ma- neuver straight ahead or in a circle. A buoy and cable are attached to the motor so that it can be recovered from the bottom of the harbor should the pon- toon sink.

���The self-propelling target. Though the pontoons are almost invisible, the gunners riddle them

��The Biggest Red Cross Flag Ever— A New York Creation

ONE of the big New York city department stores has set the pace in Red Cross flags. Across the Fifth Avenue side of the store is a flag seventy-five by one hundred feet; the hundreds of thou- sands who daily go up and down the street never fail to marvel at it. The flag was made in the store. It is ten feet larger than an American flag which formerly occupied the position it now holds.

Note the con- gested traffic in the street. Fifth Avenue is rapidly becoming the most congested thoroughfare in the world despite its width. Traffic moves five blocks at a time and there are traffic police- men nearly every block for more than a hundred blocks of its length.

The Complexities Involved in Making Shrapnel

WERE the average layman able to grasp the staggering complex- ities of chemical and mechanical de- tails involved in the making of a shrapnel shell he would be amazed. For instance, one hundred and seventy gages are required to manufacture the combination time and percussion fuse for three quarter-inch shrapnel. The powder used must have the correct m burning time or the explosion will occur too soon or too late. It is im- possible to obtain two powders with the same burning time, hence the burning time has to be determined on each lot of powder. This formerly required one and one-half hours; now it takes five minutes. Likewise, the time consumed in blending powders has been reduced from sixteen hours to fifteen minutes.

�� �