Page:Popular Science Monthly Volume 92.djvu/929

 Popular Science Monihhf

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���It is hard to realize that this remarkably life-like Dutch village scene is all sham and deceiving trickery, built to serve only a brief while until the camera has caught it

��to assume the appearance of paving stones. The roofs of the houses are made of tiling and shingles laid on loosely and easily removed. For next week this village may be in Siberia, with a roof of ice, and the canal will be the road before the dismal village inn!

��What the Twenty-Dollar Gold Piece Has Been Through

THE twenty-dollar gold piece has had an interesting career. Jewelers melt- ed it for their fine gold work, some forty years ago, and were very successful until the Government experts discovered the practice and stopped it in short order by "peppering" the gold with iridium. Fol- lowing this, unscrupulous persons at- tempted to gather scrap gold by "sweat- ing," or placing a number of coins in a bag and then shaking them violently, thus obtaining tiny particles of gold by friction. After these coins had been put through the "sweating" process it was

��an easy matter to pass them on unsus- pecting tradesmen and banks, provided, of course, that the victims did not weigh the coin. The amount of gold scrap obtained by the "sweating" process was so small that the bags had to be burned to recover it.

Another way was to "strip" a coin by putting it into an electro-chemical bath, getting thereby a slight residue of gold on a copper plate, which was afterward melted and the metals separated. Be- cause this method discolored the gold it was not very popular. One of the most successful schemes, however, was the use of a specially prepared male and fe- male die. The diameter of the die was about one one-thousandth of an inch smaller than the diameter of the coin. It was so made that after the resultant rim of metal was cut off the milled edges remained. From a single $20 coin the gold thus obtained was worth about fifty cents, and the coin, to all appearances, had not been tampered with.

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