Mental Power extended by Inventions. 87 



belief has thus been the forerunner of Science. 

 Dogma and empiricism are indispensable agents of 

 civilization ; they cannot be dispensed with by the 

 great mass of mankind, who have not the time at 

 command, nor possess the other means, necessary for 

 acquiring verified knowledge. They afford rough and 

 ready guides and useful " rule of thumb " methods, 

 though less certain and less accurate than those 

 afforded by verified and definite science. 



That various inventions, based upon scientific 

 discoveries, have greatly aided and extended our 

 mental powers is quite certain. The discovery of the 

 properties of a mixture of solution of nutgalls and 

 green vitriol, has, through the invention of ink, ex- 

 ercised an immense influence in promoting the mental 

 developement of mankind ; and the discovery of the 

 properties of esparto grass and other materials for 

 making paper has contributed to this result. Every 

 discovery also resulting in inventions which facilitated 

 the transmission of intelligence has had a similar 

 effect. Amongst these are magnetism, which, in the 

 mariner's compass greatly assisted navigation and the 

 conveyance of letters by sea ; and the steam engine 

 which facilitated the transmission of letters by land 

 and by water ; the electric telegraph, the telephone, 

 and other contrivances for transmitting ideas, have 

 also greatly promoted mental advance. The steam 

 engine, by largely abolishing physical drudgery, gave 

 time for study and mental and moral improvement. 

 It has been said that " it is impossible to lay down a 



