DISCOVERIES OFTEN DIFFERENT FROM THOSE EXPECTED. 233 



substances, 1 one of which (gallium) has been since dis- 

 covered. 



As we are, however, only in a few cases completely 

 acquainted with all the essential conditions upon which a 

 phenomenon depends, our predictions of the results of 

 unmade experiments, observations, and calculations are 

 often wrong; but if we could in all cases predict the 

 results of research with certainty, experiment and obser- 

 vation would be unnecessary. 



Substances and their forces act and react upon each 

 other in an almost infinite variety of ways in accordance 

 with the laws of their nature ; and as those laws are 

 definite, every new combination or arrangement of bodies 

 must produce new results. Any person, therefore, who 

 combines or arranges substances and their forces in a new 

 mode, and observes their action, may reasonably expect to 

 make a discovery, provided he can obtain a sufficiently 

 conspicuous instance, or is able to detect the effect. 

 Probably nearly all new discoveries in physics and che- 

 mistry are made either by observing matter and its 

 powers under new conditions, or by the aid of new or 

 improved means of observation ; and as scientific inves- 

 tigators are almost the only persons engaged in observing 

 forces and substances under new conditions, or in employ- 

 ing new means of observation, and do so with the express 

 purpose of finding new truths, the great majority of dis- 

 coveries are not the result of accident, although many of 

 them are widely different from those expected. Probably 

 no one would say that the geographical discoveries made 

 by Dr. Livingstone in the interior of Africa were acci- 

 dental, although some of them were different from those 

 he expected. 



The following are examples of discoveries more truly 

 1 CJwmieal News, No. 839, Dec. 24, 1875. 



