Page:Popular Science Monthly Volume 88.djvu/57

Popular Science Monthly

GERMAN has invented a breathing apparatus for divers which does away with the cumbersome hand pump and tubes.

A diver can descend in the water with no other impediment than a safety rope and telephone wires, and these can be dispensed with if desired. The feature of most unusual interest in connection with the equipment is the means of refreshing the air. Vitiated air from the lungs is forced into a tank containing several layers of potash through which it percolates. The potash cartridge absorbs the carbon dioxide. The oxygen supply is re plenished from a small oxygen tube as it is required.

Caustic potash has been found to be the most satisfactory chemical for absorption purposes. In this new device it is placed in a number of shallow trays one upon the other; so that the air passes through each layer.

OME years ago, when archeological researches were going on at Capua, Italy, the excavators came upon an ancient tomb. Upon opening it they found it to contain a rather unusual relic of the past. A skeleton was found, and with it were numerous objects supposed to have been associated with the living personage of whom this was the sepulchre. One of the objects, as to the use of which there was no doubt, was an artificial leg. One of the leg bones of the skeleton was missing, indicating that the leg had been interred with the wearer. The artificial limb, a creditable mechanical contrivance, was made of a combination of bronze, wood and iron.

Fortunately, the tomb also contained some evidence as to the age of its contents and the period in which the wearer of the wooden leg might be supposed to have been walking on it. Three vases were found which were decided upon as being representative of the period which had ended some three centuries before the birth of Christ.

With this remote date practically fixed as a time when very advanced forms of artificial limbs were in use, an interesting light is shed on the antiquity of their intention. It is natural that there should be a considerable period of development between the first crude effort and a fairly well-finished combination of wood and two different metals.

The artificial leg here mentioned may still be seen, preserved in the museum of the Royal College of Surgeons in London. It is an evidence that archeology may teach even the surgeon.