Page:Popular Science Monthly Volume 90.djvu/263

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Popular Science Monthly


��the slightest knowledge of checkers can understand the game as it is played upon the board. There are one thousand nine hundred and twenty lamps displayed upon the board and one thousand and twenty- four lamps in the checker squares.

The board is placed in a perpendicular position. It can be seen at a considerable distance when illumi- nated at night. The squares upon which the checkers move

have a circular opening or ring, behind which the lamps project. When in play each lamp has the appearance of a disk to conform to the size of a checker in relation to the checker square.

In all checker games the opening move goes to the black. The first move is con- sidered an advantage, and checkers are reversed after each game. On the auto- matic board this rule is followed out. The green checker represents the black and moves first, playing from the bottom of the board the first game and from the top of the board the second game, reversing each game.

The board may be used for other games, or for advertising purposes.






As the cylinder re- volves the runners engage grooves on the record. This raises or lowers the switch arms and makes or breaks the circuit connection to the board lamps



��The games or records are first worked out on sheet brass and then placed on a cylinder which revolves slowly. On the under side of the switch arms needles, placed on a slant, drag on the surface of the revolving cylinder

��Conveying Music by Wireless — A Modern Miracle

THERE is more fact than fancy in that old song, "There is music in the air." You can lie in your comfortable berth on a liner speeding out to sea and hear the clear, limpid notes of Caruso as he sihgs to an opera audience on land, many miles away. In the seclusion of your own home you can hear the world's greatest artists and catch the spirit of the audiences to which they are singing, even to the minutest d^ails of applause, although the opera house may be in a distant city. These are modern wonders wrought by wireless.

Not long ago the passengers on a steamer far out on Long Island Sound had the inter- esting experience of hearing musical selec- tions colne in through their receivers. Only recently a group of wireless engineers and musicians held sensitive receivers to their ears and heard music which was conveyed to them by wireless from a distant part of the city.

Briefly, this demonstration was made as follows: From the sound-box of a talking machine the music was led into the trans- mitter of a wireless sending station. Here it was transformed into an electric current which changed its direction several hundred thousand times a second. Then it was transformed into electromagnetic waves which traveled in all directions away from the aerial wires at the rate of 186,000 miles a second — the speed of light. The waves which reached the aerial wires of the re- ceiving station were then absorbed and converted back again into an electric cur- rent. The music was then led into the telephone receivers worn by the audience.

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