254 SCIENCE IN SHORT CHAPTERS. 



and have clearly distinguished between such hypotheses 

 and the established facts of universally admitted science. 

 Instead of doing this, he has so mixed up the actual dis- 

 coveries of indisputable facts with these mere mathematical 

 fancies as to give them both the semblance of equally au- 

 thoritative scientific acceptance, and thus, without any 

 intention to deceive anybody, must have misled nearly all 

 the outside public who have heard or read his address. 



As these letters are mainly intended for those who are 

 too much engaged in other pursuits to study science syste- 

 matically, and as most of the readers of such letters will, as 

 a matter of course, read the inaugural address of the Presi- 

 dent of the British Association, I have accepted the duty 

 of correcting among my own readers the false impression 

 which this address may create. 



As a set-off to the authoritative utterances of Sir "W. 

 Thomson on the subject pf atoms, I quote the following 

 from an Italian philosopher, who, during the present year, 

 is holding in Italy a position very similar to that of the 

 annual President of our British Association. 



Professor Cannizzaro has been elected by a society of 

 Italian chemists to act as this year's director of a Chronicle 

 of the Progress of Chemical* Science in Italy and abroad. 

 In this capacity he has published an inaugural treatise on 

 the history of modern chemical theory, in the course of 

 which he thus speaks of the over-confident atomic theorists: 

 " They often speak on molecular subjects with as much 

 dogmatic assurance as though they had actually realized 

 the ingenious fiction of Laplace had constructed a micro- 

 scope by which they could detect the molecules, and observe 

 the number, forms, and arrangements of their constituent 

 atoms, and even determine the direction and intensity of 

 their mutual actions. Many of these things, offered at 

 what they are worth that is, as hypotheses more or less 

 probable, or as simple artifices of the intellect may serve, 

 and really have served, to collocate facts and incite to 

 further investigations which, one day or other, may lead 

 to a true chemical theory; but, when perverted by being 

 stated as truths already demonstrated, they falsify the in- 

 tellectual education of the students of inductive science, 



