Il8 THE SEVEN FOLLIES OF SCIENCE 



lations with generally accepted physical facts, to be nebu- 

 lous and inaccurate. 



It does not follow, however, that because myself and 

 some others cannot form such a clear conception of a fourth 

 dimension as we can of the third, that, therefore, the theory 

 is erroneous and the alleged conditions non-existent. Some 

 minds of great power and acuteness have been incapable 

 of mastering certain branches of science. Thus Diderot, 

 who was associated with d'Alembert, the famous mathe- 

 matician, in the production of " L' Encyclopedic," and who 

 was not only a man of acknowledged ability, but who, at one 

 time, taught mathematics and wrote upon several mathe- 

 matical subjects, seems to have been unable to master the 

 elements of algebra. The following anecdote regarding 

 his deficiency in this respect is given by Thiebault and 

 indorsed by Professor De Morgan : At the invitation of 

 the Empress, Catherine II, Diderot paid a visit to the 

 Russian court. He was a brilliant conversationalist and 

 being quite free with his opinions, he gave the younger 

 members of the court circle a good deal of lively atheism. 

 The Empress herself was very much amused, but some of 

 her councillors suggested that it might be desirable to 

 check these expositions of strange doctrines. As Cathe- 

 rine did not like to put a direct muzzle on her guest's tongue, 

 the following plot was contrived. Diderot was informed 

 that a learned mathematician was in possession of an al- 

 gebraical demonstration of the existence of God and would 

 give it to him before all the court if he desired to hear it. 

 Diderot gladly consented, and although the name of the 

 mathematician is not given, it is well known to have been 

 Euler. He advanced toward Diderot, and said in French, 

 gravely, and in a tone of perfect conviction : " Monsieur, 



