Conditions under which discoveries are made. 3 



London. It was noticed on testing a cable by 

 means of a voltaic battery (the cable being sub- 

 merged in water) that discharges of electricity 

 flowed from the cable after the battery was removed ; 

 this circumstance was investigated by Faraday, and 

 led to improvements in submarine telegraphy. In 

 each of these instances the same general method as 

 that used by scientific discoverers was however 

 employed, viz., new experiments were made (though 

 not intentionally) by putting matter and its forces 

 under new conditions, and new results were 

 observed. 



Nearly all great modern scientific discoveries have 

 been made by teachers of science and others, who 

 spend a large portion of their lives in experimental 

 investigation, searching for new truths, and not by 

 persons who have hit upon them by accident. The 

 greatest discoveries in physics and chemistry in 

 modern times, were made chiefly' by such men as 

 Newton, Cavendish, Scheele, Priestley, Oersted, 

 Volta, Davy and Faraday : all great workers in 

 science. 



It is either by observing matter and its forces 

 under new conditions or from a new aspect, that 

 nearly all discoveries are made; thus Priestley 

 placed some oxide of mercury in an inverted glass 

 vessel, and heated it by means of the Sun's rays and 

 a lens, and discovered Oxygen. This substance was 

 nearly discovered by Eck de Sulsbach three hundred 

 years before ; he heated six pounds of an amalgam 



