\ 



KNOWLEDGE AND OPINION. 93 



to tlie Existence of Ntapoleon Bonaparte"; but 

 Biicli persons, if any there be, are properly consid- 

 ered by Her Majesty's Commissioners in Lunacy 

 as fit subjects for their polite inquiries. People 

 may be ignorant of these facts — a great many 

 people are ; but they are nevertheless facts, not 

 mere matters of opinion. Not to know them 

 is easy enough, but seriously to doubt them is 

 simply ridiculous. Though many estimable Chi- 

 nese are doubtless unaware of the very existence 

 of Regent Street, Regent Street is nevertheless a 

 genuine, a solid, and a sufficiently tangible reality. 

 Nobody who has ever been there can deny its 

 existence, unless he is either a confirmed lunatic 

 or a confirmed teller of untruths. 



It is just the same with the vast mass of scien- 

 tific knowledge. For science, as has well been 

 said, is nothing more than ordinary experience, 

 accurately observed and reduced to rules of pre- 

 cision. Everybody knows that wood burns; that 

 iron, if exposed to damp and air, soon rusts ; that 

 meat, kept too long, goes bad ; that quicklime, 

 wh«in wetted, steams and gets warm. Well, 

 chemistry is only a systematic collection of similar 

 facts about an immense number of natural and 

 artificial bodies. Everybody knows that in cold 

 weather water freezes ; that in hot weather ice 

 melts ; that, if 3'ou stretch India-rubber, it jumps 

 back again ; that, if you put mutton-fut upon the 



