THE FIELD OF DISCOVERY. 65 



compass and quadrant ; the steam-engine, and the 

 apparatus by means of which it opens and shuts its 

 own valves ; printing in all its forms, and with all 

 its improvements ; chronometers that keep correct 

 time in spite of the changes of heat and of cold ; 

 and, indeed, all the more wonderful and useful appli- 

 cations that have been made of the properties of 

 matter generally, or of the particular properties of 

 particular kinds or combinations of matter, have 

 almost all been the result of what we, in common 

 language, are in the habit of calling chance : that is, 

 they have been made by those who, as we say in 

 common language, were not u the most likely per- 

 sons to make them." But when we say that, we 

 are wrong; and the discoveries are not owing to 

 chance, any more than any thing else is so owing. 

 They are the effects of causes, just as certainly as 

 burning is the effect of throwing a lighted brand 

 among dry straw or chips of wood, or as pain in 

 the fingers is the consequence of taking hold of a 

 live coal with them; and the persons who made 

 those discoveries every discovery that has been 

 hitherto made, as well as all those who shall make 

 future ones, have done so, not by any thing that can 

 in any way be called chance, but simply because 

 they were in the right road to the discovery a road 

 which all the rest of mankind had missed. No man 

 can go a determinate way to the discovery of that 

 which is not known, because, before he can go to 

 it he must know both what and where it is ; but, 

 where all is unknown, no man can tell what he may 

 not discover, if he has but field enough. The field for 

 all discovery is nature ; and, therefore, he whose 

 observation commands the most of that, is the man 

 most in the way of useful discovery, whatever that 

 discovery may be. 



Now the man who has it in his power to make 

 useful discoveries is placed in the very highest and 

 happiest situation in which a man can be placed 

 F2 



