XIII 



INSTRUMENTS OF PRECISION IN THE AGE OF 

 NEWTON 



DURING the Newtonian epoch there were numerous 

 important inventions of scientific instruments, as 

 well as many improvements made upon the older ones. 

 Some of these discoveries have been referred to brief- 

 ly in other places, but their importance in promoting 

 scientific investigation warrants a fuller treatment of 

 some of the more significant. 



Many of the errors that had arisen in various scien- 

 tific calculations before the seventeenth century may 

 be ascribed to the crudeness and inaccuracy in the 

 construction of most scientific instruments. Scientists 

 had not as yet learned that an approach to absolute 

 accuracy was necessary in every investigation in the 

 field of science, and that such accuracy must be ex- 

 tended to the construction of the instruments used in 

 these investigations and observations. In astronomy 

 it is obvious that instruments of delicate exactness are 

 most essential; yet Tycho Brahe, who lived in the 

 sixteenth century, is credited with being the first 

 astronomer whose instruments show extreme care in 

 construction. 



It seems practically settled that the first telescope 

 was invented in Holland in 1608; but three men, 

 Hans Lippershey, James Metius, and Zacharias Jansen, 



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