152 THE WONDERFUL CENTURY. CHAP. xv. 



comen to the powerful and economical engines of Boul- 

 ton and Watt. The principle, however, was known long 

 before, and had been practically applied in the previous 

 century by the Marquis of Worcester and by Savery; 

 and the improvements made by Watt, though very im- 

 portant, had a very limited result. The engines made 

 were almost wholly used in pumping the water out of 

 deep mines, and the bulk of the population knew no 

 more of them, nor derived any more direct benefit from 

 them, than if they had not existed. 



In the seventeenth century, the one great and far- 

 reaching invention was that of the Telescope, which, in 

 its immediate results of extending our knowledge of the 

 universe and giving possibilities of future knowledge not 

 yet exhausted, may rank with spectrum analysis in our 

 own era. The Barometer and Thermometer are minor 

 discoveries. 



In the sixteenth century we have no invention of the 

 first rank, but in the fifteenth we have Printing. 



The Mariner's Compass was invented early in the 

 fourteenth century, and was of great importance in ren- 

 dering ocean navigation possible and thus facilitating 

 the discovery of America. 



Then, backward to the dawn of history, or rather to 

 prehistoric times, we have the two great engines of 

 knowledge and discovery the Indian or Arabic 

 numerals leading to arithmetic and algebra, and, more 

 remote still, the invention of alphabetical writing. 



Summing these up, we find only five inventions of 

 the first rank in all preceding time the telescope, the 

 printing-press, the mariner's compass, Arabic numerals, 

 and alphabetical writing, to which we may add the 



