168 annual kepokt smithsonian institution, 1908. 



Fundamental Differences Between the Old and New Wireless 



Schools. 



The ditferences between the two methods are shown in tabuhited 

 form : 



The history of these two antithetical lines of development will be 

 treated of separately. 



Development and Perfecting of Sustained Oscillation-non- 

 MicROPHONic Receiver Method (Period 1898-1902). 



the current-operated receiver. 



The first essential for the development of the system was, of 

 course, a quantitatively responsive receiver. Several forms of this 

 were tried, including the modification of the Boys' radio-micrometer 

 (consisting of a light thermo couple suspended in the field of a per- 



