SCIENCE OF THE SIXTEENTH CENTURY. 97 



motion, yet it would obviously remain at rest. And Stevinus reasons 

 that as the horizontal portion A c could not act by its weight to 

 draw the chain one way rather than the other, the remaining parts, 

 namely, that which lies on the incline, and that which hangs perpen- 

 dicularly, must balance each other. - Now, as the weights of these 

 parts are proportional to their respective lengths, it follows that the 

 power acting along the inclined plane will balance a weight to which 

 it has the same proportion as the height B c has to the length A B of the 

 inclined plane. When the principle of the action of oblique forces had 

 thus been established in this one case, various other instances of the 

 same kind of action were investigated by other authors, who employed 

 the principle established by Stevinus. The first suggestion of the fun- 

 damental principle of Hydrostatics, namely, that the pressure at any 

 point in a liquid is in proportion to the depth of the point below the 

 surface, is also due to Stevinus. 



The rise of Chemistry in the sixteenth century may be illustrated 

 by the labours of three persons, each of whom opened out a new and 

 unexplored field for the science. Paracelsus applied chemistry to medi- 

 cine ; Agricola founded the metallurgical department of the science ; 

 and Palissy showed how chemical truths might be utilized in extend- 

 ing the resources of technical art. 



PARACELSUS (1493 1 54 1 )> whose real name was AURELIUS PHI- 

 LIPPUS THEOPHRASTUS AB HOHENHEIM, was a native of Switzerland. 

 After having visited nearly every country in Europe as a student in 

 medicine, and having in many places practised the healing art with 

 great reputation, he was in 1526 appointed professor of surgery at 

 Bale. He there broke through all the established rules and prece- 

 dents by delivering his lectures to his students in their native German 

 tongue, and he is therefore entitled to the merit of being the first 

 savant who sought to popularize science. But at his first lecture 

 the students were still more astounded by his avowed contempt of 

 the. venerated medical authorities of that day, namely, Hippocrates, 

 Galen, and Avicenna. Paracelsus had tlie works of these authors 

 brought into the room, and there he deliberately committed them to 

 the flames, informing his audience that his beard, his hat, and his 

 shoes knew more of medicine than all the physicians of antiquity put 

 together. Our readers will perceive from this incident that Paracelsus 

 was not a man likely to fail in attaining his object through diffidence 

 in his own abilities, or modesty in proclaiming his own merits. Para- 

 celsus marks an era in the history of chemistry, because he showed 

 that this science was worthy of being pursued apart altogether from 

 such objects as the alchemists sought, and that it was capable of con- 

 ferring solid benefits on mankind by providing the physician with new 

 and potent drugs. Paracelsus is also a conspicuous figure in the his- 

 tory of medicine, as the earliest and boldest rebel against the tyranny 

 of ancient authority. He attacked the rival sects of Galenists and 



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