Crowther, J. G.  1899- <br/><br/>
Discoveries and inventions of the 20th century / 
J. G. Crowther 
 - 4th ed., entirely rev. and rewritten. 
 - London :  Routledge & Paul,  1955. 
 - xvii, 432 p. :  ill. ;  23 cm. 
<br/><br/> Includes index  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Inventions.
<br/><br/><label>Dewey Class. No.: </label>608  / CRD 1955