THE REVIVAL OF SCIENCE 267 



As anatomy on the biological side, so astronomy 

 on the physical, led the way. Copernicus had 

 claimed that the sun was the centre of our system ; 

 but it was not until the following century, when 

 the truth of his views was mathematically proved, 

 that, first, men of science, and, later, the world at 

 large, abandoned the views of Ptolemy, which, like 

 those of Aristotle, of Galen and of Hippocrates, 

 had obsessed the learned world since classical 

 times. 



The great outburst of scientific inquiry which 

 occurred during the seventeenth century was 

 partly the result, and partly the cause, of the 

 invention of numerous new methods and innumer- 

 able new instruments, by the use of which advance 

 in natural knowledge was immensely facilitated. 

 Early in the century (1614), Napier of Merchiston 

 had made known his discovery of logarithms, and 

 logarithmic tables were first published in 1617. 

 Seven years later, the slide rule, which to-day 

 plays a large part in physical and engineering 

 science, was invented by Edmund Gunter. Deci- 

 mals were coming into use and, at the close of the 

 sixteenth century, algebra was being written in 

 the notation we still employ. William Gilbert, 

 physician to Queen Elizabeth, published his 



