Page:Popular Science Monthly Volume 91.djvu/41

This page needs to be proofread.


Popular Science Monthly

��How Fast Is Your Typist? This Inge- nious Machine Will Time Her

INVENTORS have tried for years to put a counter on the typewriter to estimate the speed of the typist, but the efforts have always been confined to a count of the words written. A recently patented device, called a cyclometer, counts every stroke which the typist makes on the keyboard. It is fastened to the escapement wheel of the typewriter. This wheel does not move when the carriage is shoved backward and forward.

One firm employing fifty typists found that its work was below nor- mal by cyclometer cou nt and later that it had some very rapid typists and; some very slow ones. The rate of pay had always been based on the number of years of service, and many of the slow ones were being paid for the work done by the rapid operators. This of course was quickly adjusted

���The timing device records not only the number of words written but the number of strokes made

��The Grave-Digger Beetle — Nature's Sanitary Policeman

WHEN an animal dies in a garden or in the woods and decomposition be- gins, carrion bugs come from far and near. A dead bird, a mouse or a harmless snake wantonly killed by some wanderer pro- vides a banquet for hundreds of insects. Among these the "grave-diggers" are found, embracing forty-three species, twelve of

�� ��The beetles dig the earth away from under the dead body so that it sinks into its grave. Then they cover it over

��25

which are found in Europe, the rest in America.

You can identify these beetles by the two jagged yellowish-red or reddish trans- verse bands upon their black wing-covers. Their scientific name (Necrophorus) means no more than "buriers of the dead." As undertakers, the insects have legs especially adapted for digging. A grave-digger beetle has a most extraordinary sense of smell. He can detect the peculiar odor of de- composition a long dis- tance away and flies to the dead thing as straight as an arrow. His remarkably keen nose is situated in his club-like feelers. As a rule several grave- diggers are found near a dead body. They crawl under it and scratch the supporting earth away, so that the body soon lies in a hollow. Gradually the body is lowered until it sinks below the surface. Then it is covered with earth. The female lays her eggs around the interred form, thus insur- ing for the newly hatched larvae a plentiful food supply.

It is interesting to note that these grave- diggers can produce a curious creaking noise, by rubbing the fifth abdominal ring, which has two longitudinal projecting bars, on the under edge of both wing-covers. This noise is only made when the bug is attacked; it has therefore been con- sidered an expedient to frighten away Nature further fortifies the beetle with a general musk- like odor and by a particu- larly strong smelling juice which it exudes like a skunk if touched. This odor serves as a protection from human beings, especially, as it is peculiarly unpleasant and penetrating. If the beetle is handled it requires several washings to remove the odor from the fingers.

The grave-diggers are among the most useful of beetles. They have been designated Nature's sanitary police. — Dr. E. Bade.

��its enemies.

�� �