WIRELESS TELEGRAPHY. 59 



man knowingly would eat, and wliicli are undoubtedly harmful 

 to all. 



The knowledge gained by investigations in chemical and bac- 

 teriological 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 ques- 

 tionable 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 pre- 

 served by the addition of such agents as formaldehyde, it is time 

 that the public should demand some restrictive measures. 



WIRELESS TELEGRAPHY. 



By Prof. JOHN TROWBRIDGE, 



DIRECTOK OF JEFFEBSON 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, with- 

 out which telephony and wireless telegraphy would be impossible. 

 To my mind it is the most interesting skeleton there, and if physi- 

 cists marked the resting places of their apparatus laid to apparent 

 rest and desuetude, this merits the highest sounding and most sug- 

 gestive inscription. It is called a transformer, and consists merely 

 of two coils of w^ire 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, 



