56 PROGRESS OF SCIENCE. 



which was to become the ultimate object of future research. 

 As a chemist, he separated gold from silver (in a mixture of 

 the two metals) by means of nitric acid ; pointed out that 

 air feeds a flame. As a physician, he applied new remedies 

 (laudanum and antimony amongst others), and discovered the 

 general law of nutrition. His follower Libavius (1550 1616) 

 continued his chemical work, and discovered the process of 

 making red glass by the oxide of gold. His Alchymia 

 Recognita contains valuable descriptions of old, and new, 

 processes. 



1494 1555. Agricola was the founder of modern metal- 

 lurgy, removing it from the alchemist's laboratory to the 

 foundry an immense stride in practical chemistry. He was 

 also the discoverer of bismuth (1529). 



14971558. Fernel measured a DEGREE by the revolu- 

 tion of a wheel in 1527, ascertaining thereby the earth's 

 circumference to be 24,480 Italian miles nearly the same 

 result as Al Mamun's. 



1500 155- Tartaglia caused mechanics to progress in 

 several ways ; may be called the father of ballistics, having 

 been the first to explain the laws governing the flight of 

 projectiles, which Leonardo had understood sixty years 

 before, but without fully explaining them. 



15011576. Cardan, the inventor of "the CARDAN 

 RULE/' also advanced theoretical and practical mechanics. 



1510 1590. Palissy explained the origin of springs and 

 of FOSSILS, and improved the ceramic art. Glazed pottery 

 for domestic use is due to him. 



1512 1594. Mercator, after Prince Henry, contributed 

 most to revive GEOGRAPHY on scientific principles (Tabulae 

 Geographic), constructing marine Charts on what is called 

 Mercator's Projection representing latitudes and longitudes 

 by lines; he also revived astronomical chronology, and 

 restored hydromechanics, at least partially. 



1522 1565. Ferrari greatly improved ALGEBRA, and 

 resolved algebraic equations of the third and fourth degrees. 



1526 1594. Palestrina made music AN ART as well as 

 A SCIENCE. His compositions have remained unsurpassed. 



1537 1619. Aquapendente (Fabricius ab), tutor of 



