CHAPTER IV 

 THE CHEMICAL AND NATURAL SCIENCES 



1. CHEMISTRY 



IN the sciences which we have hitherto considered, 

 observation and practice have, up to a certain 

 point, guided theory. It was not the same with 

 chemistry, the theories of which were closely connected 

 with metaphysics and had no great influence on the 

 technical processes. The first gropings of chemical 

 technique are very ancient. They seem to go back to a 

 prehistoric epoch, to the time when metals were first 

 used for manufacturing weapons, and when certain 

 alloys were perceived to be advantageous. Amongst 

 these alloys, that of tin and copper was specially 

 important. From the most remote antiquity Egypt 

 was an important centre of the trade in tin ; which in 

 later times was supplied by Phoenician traders. 1 Other 

 metals were afterwards discovered and alloyed. In 

 Egypt, the method of treating them was preserved by 

 tradition in the form of short and probably mysterious 

 receipts whose secret was jealously guarded by the 

 priests. Certain hieroglyphic signs, completed by oral 

 instructions, were sufficient to ensure the transmission 

 of the methods of manufacture. 



As to the Greeks, the sum of their practical know- 

 ledge amounts approximately to the following : " They 

 knew how to prepare certain salts of copper, of 



X M. Delacre, Histoire de la Chimie, Gauthier-Villars, Paris, 

 1920, p. 16. — J. de Morgan, L'Humanitd prihistorique, Renais- 

 sance du Livre, Paris, 1921, p. 119. 



203 



