344 ACROPHYSICS. 



and earth j and considered light as also a material substance. Aris- 

 totle maintained the idea of a series, or succession of elements ; the 

 highest being the lightest: and he regarded matter, form, and 

 privation, as the three great agents by which the world is con- 

 trolled, (p. 20.) 



We have now pointed out some of the errors of the ancient philo- 

 sophers ; reserving the truths which they discovered for the history of 

 the different branches of Acrophysics. We may add that Archimedes 

 thought it beneath the dignity of philosophy to write explanatory and 

 practical works on the sciences ; which, perhaps, was the greatest 

 error that this profound philosopher ever entertained : as it caused 

 the loss of much valuable information to succeeding ages. The 

 knowledge of the ancients, in this department of science, was pre- 

 served in part by the Arabians ; and by them transmitted to modern 

 Europe, with some important additions, (p. 289). Among the ear- 

 liest pioneers of modern science, we may mention Roger Bacon, an 

 English monk or Friar, whose discoveries in optics and chemistry 

 deserve an honorable mention. Still, the limits of physical truth 

 were confined, and its march impeded, in his time, by the metaphy- 

 sical subtleties and vagaries of the schoolmen, based on the high 

 authority of Aristotle. To Francis Bacon., Lord Verulam, whose 

 profound work, entitled "Novum Organum Scientiarum," in contra- 

 distinction from the Organon of Aristotle, first unfolded the right 

 method of studying nature, by observation, experiment, and a careful 

 induction of principles from numerous and well known facts ; to 

 him is modern science indebted, at least in a considerable degree, 

 for its rapid and continuous progress, among all enlightened nations, 

 down to the present time. 



Of the Acrophysical sciences, Astronomy was the first to emerge 

 from darkness, when Copernicus and Galileo revived the true solar 

 system ; the theory of which has since been developed by Newton 

 and La Place. Galileo also laid the foundation of Dynamics, or the 

 theory of variable motion, with which the ancients were slightly or 

 not at all acquainted : and his pupil, Torricelli, originated the science 

 of Pneumatics, by discovering the ponderability of the air. The 

 prismatic decomposition of Light, by Newton, gave a new impulse 

 to the study of Optics, which had previously been limited to a few 

 of the more common phenomena of reflection and refraction. The 

 discoveries of Dr. Gilbert, first elevated Magnetism to the rank of 

 a science ; and formed a nucleus on which has arisen the kindred 

 science of Electricity. Galvanism originated, in the last century, 

 with the discoveries of Professor Galvani ; and Electro-Magnetism, 

 in the present century, with those of Professor Oersted ; to which 

 Dr. Seebeck has since added a new class of phenomena, in those of 

 Thermo-Electricity. Chemistry first took a scientific form in the 

 hands of Beccher and Stahl ; though its true theory was more recently 

 made known by Lavoisier and Dalton. To Dr. Black we are indebted 

 for the initial discoveries in Pneumatic Chemistry, and some of the 

 most important laws of Calorics. 



Thus rapid and brilliant has been the modern progress of the 

 sciences included in the present department. We proceed to treat 



