The Eighteenth Century 171 



Several other early eighteenth-century writers on physics paid 

 particular attention to various luminescences. One o£ them was 

 Hermann Fredrick Teichmeyer (1685-1744), a German doctor of 

 medicine, who became successively professor of experimental physics, 

 medicine, botany, surgery, and anatomy at the University of Jena. 

 His Elementa Philosophiae Naturalis Experirnentalis first appeared 

 at Jena in 1717. Teichmeyer was a Cartesian and took pains to 

 explain in pars I, caput XVIII, " De Luce," how " Light is pure fire 

 or the material of the first element of Descartes which moves vio- 

 lently the unsteady material of the second element or the aetherial 

 globules." In the 1733 edition Teichmeyer explained how light 

 might be liberated from either liquid or solid bodies and mentioned 

 a surprising number of luminescences, including the mercurial 

 barometer, glass tubes on rubbing, the various experiments of Hauks- 

 bee, the Baldewinian, Bononian, and Hombergian phosphors, as 

 well as English phosphorus in solid and liquid form (phosphorus 

 dissolved in oil of cloves) . Bioluminescences were not discussed. 

 Bartholin's De Luce Animalium was mentioned in connection with 

 ignes fatui, and the various manifestations of the aurora borealis 

 were described in a chapter, " De Meteoris." Teichmeyer also wrote 

 a pharmacology, Institutiones Materiae Medicae (1737), in which 

 he recommended " English phosphorus " in kidney troubles, par- 

 ticularly for dissolving renal concretions. 



Another writer on physics, Georg Erhard Hamberger (1697-1755) , 

 at various times professor of medicine, physik, botany, anatomy, and 

 surgery at the University of Jena, published his Elementa Physices 

 (Jena, 1727) , a popular volume on a wide variety of physical phe- 

 nomena, which passed through many editions, the fifth in 1761. 

 Hamberger paid particular attention to the light of the barometer 

 and luminescences which appear from rubbing materials. He de- 

 scribed the various experiments of Bernoulli and others published 

 by the French Academy, regarding the phenomena as a kind of 

 fire. He thought that an air current moved toward the vacuum 

 because the surrounding glass of the barometer attracted light 

 bodies to it while the luminescence appeared.-^ 



Practically the same material is contained in the book of Johann 

 Melchior Verdries (1679-1735) , a professor of physics and medicine 

 at the University of Giessen. His Physica, sive in Naturae Scientiam 

 Introductio (Gissae, 1728) contained a chapter " De Qualitatibus 

 Visibilibus," in which a large number of luminescences were 

 discussed. 



^^ According to P. T. Riess, Die Lehre von der Reibungselektricitat 2: 149, Berlin, 

 1853. 



