8 



times witli great care and attention—and frequently in 

 the presence of some judicious person. As the testi- 

 mony of the senses is not always sufficient, and tlie 

 most careHil observer is liable to eiT, I neither ex- 

 pect, nor even wisli, the conclusions should be adopt- 

 ed until tlie experiments shall have been repeated by 

 others ; and if it should be found tliat I have erred 

 in any part of them, I shall ever be ready to retract 

 the assertion— for the interest of truth and the wel- 

 fare of science are infinitely of more value than the 

 reputation of an individual. 



