Page:Popular Mechanics 1928 11.pdf/36

 



Shaped like a fountain pen, a small container for gas fumes, to foil bandits, has a lever that shoots the vapors a distance of twelve feet and more. It is intended for the use of bank tellers, clerks and others, and is deceptive to an intruder as its appearance gives no indication of its purpose. The "pen" unscrews in the middle for the insertion of a gas cartridge.

 

The expression, "he is a man of iron nerves," may be more true literally than has been supposed, an interesting series of tests just concluded by Prof. Ralph S. Lillie, of the University of Chicago, indicates. His experiments have revealed a striking similarity between nervous action, particularly heart action. and the behavior of iron wire in a nitric-acid bath. A pure iron wire, one to five centimeters long, was immersed in a nitric-acid solution of sixty to eighty per cent. A colorless film immediately formed over the wire and, if one end was scratched, a wave traveled rapidly along the wire. When a glass tube was placed in the acid, around one end of the wire, rhythmical waves passed the length of the piece at the rate of fourteen to 120 times a minute, depending upon the strength of the solution, the temperature and the length of the wire. Dr. Lillie concluded that a sort of battery was formed. The film, only one molecule in thickness, acquired an electrical charge negative to that of the wire. When the film was scratched, a current was set up which dissolved the film next to the bare spot. This continued until the bare spot, which was seen as a wave, had passed the length of the wire. The film forms again after the wave has passed. The influence of temperature, electrical polarization, concentration of acid and length of the wire, have been shown to be the same as their influence on living nerves.

 

A sturdy crane picked up a house and floated it several miles across the water to a new location in Rotterdam recently. The crane was part of the equipment of a powerful harbor vessel, used in wrecking, dredging and other heavy tasks.



