Page:Popular Science Monthly Volume 56.djvu/67

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59
WIRELESS TELEGRAPHY.

man knowingly would eat, and which are undoubtedly harmful to all.

The knowledge gained by investigations in chemical and bacteriological science have enabled the unscrupulous to take putrid liver and other disgusting substances and present them in such a form that the most fastidious palate would not recognize their origin. In this way the flesh from diseased animals and that which has undergone putrefactive changes may be doctored up and sold as reputable articles of diet. The writer does not believe that this practice is largely resorted to in this country, but that questionable preservatives have been used to some extent has been amply demonstrated by the testimony of the manufacturers of these articles themselves, given before the Senate committee now investigating the question of food and food adulterations. It is certainly true that most of the adulterations used in our foods are not injurious to health, but are fraudulent in a pecuniary sense; but when the flesh of diseased animals and substances which have undergone putrefactive decomposition can be doctored up and preserved by the addition of such agents as formaldehyde, it is time that the public should demand some restrictive measures.

 
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WIRELESS TELEGRAPHY.
By Prof. JOHN TROWBRIDGE,
DIRECTOR OF JEFFERSON PHYSICAL LABORATORY, HARVARD UNIVERSITY.

I NEVER visit the historical collection of physical apparatus in the physical laboratory of Harvard University without a sense of wonderment at the marvelous use that has been made of old and antiquated pieces of apparatus which were once considered electrical toys. There can be seen the first batteries, the model of dynamo machines, and the electric motor. Such a collection is in a way a Westminster Abbey—dead mechanisms born to new uses and a great future.

There is one simple piece of apparatus in the collection, without which telephony and wireless telegraphy would be impossible. To my mind it is the most interesting skeleton there, and if physicists marked the resting places of their apparatus laid to apparent rest and desuetude, this merits the highest sounding and most suggestive inscription. It is called a transformer, and consists merely of two coils of wire placed near each other. One coil is adapted to receive an electric current; the other coil, entirely independent of the first, responds by sympathy, or what is called induction,