THE BORDERLAND OF CHEMISTRY AND ELECTRICITY. 
209 
In the fifteenth century chemical facts were increasing, but the old 
idea of what matter was, still held good. During this period medical 
chemistry began, various investigators being in search of the “ Elixir 
of life,” as a remedy for all disease. Basil Valentine describes the 
medical values of many of his compounds ; in his works the properties 
of antimony compounds were so well given that even at the beginning 
of this century they had not been improved on. At the beginning of the 
seventeenth century the same author proved that galena contained 
sulphur, and iron pyrites gold. Even so late as 1709 Homburg stated 
that pure silver melted with pyrites contained gold; other investigators 
meeting with similar results, it was supposed that pure silver did con¬ 
tain gold. 
Paracelsus (fifteenth century) discovered the link between chemistry 
and medicine, but he still held the transmutation of metals to be 
possible. Van Helmont (sixteenth and seventeenth centuries) was the 
first to upset the Aristotle theory of the four elements, and described fire 
as a force, not a material; he denied that earth was an element; he was 
also the first to use the term gas; his gas sylvestre was clearly shown 
to be different from the atmosphere, as he found it to be produced 
during fermentation, and also during combustion, and stated that it 
was present in the Grotto del Cane at Naples; he also mentioned a 
gas evolved from manure and decaying organic matter, which was 
inflammable, as against his gas sylvestre, which was not inflammable; 
the inflammable gas would be sulphuretted hydrogen, the gas sylvestre 
carbonic acid. 
Lemery (1675) first showed the distinction between inorganic and 
organic chemistry. Robert Boyle (1627-1691) overthrew Aristotle’s 
doctrine as well as that of Paracelsus; his book was entitled The 
Sceptical Chemist, or Chemico-physical Doubts and Paradoxes touch¬ 
ing the experiments whereby Spagyrists are wont to endeavour to 
evince their salt sulphur and mercury to be the true principles of 
things. The first edition was published in 1661; he was the first true 
scientific chemist and began a chapter of science, the aim of present 
scientists, which may be named the simple advancement of knowledge 
by the observation of facts; it was he who wrote “ On the Borderland 
of Chemistry and Physics, ” in his experiments and investigations on 
the elasticity of the air he discovered the great law which exists between 
volumes of gases and the pressures to which they are subjected, and 
which still bears his name, known as Boyle’s Law. 
Hooke (1665) and John Mayon (1681) wrote pamphlets on combus¬ 
tion which were more accurate than numerous other subsequent attempts; 
these two philosophers observed that when metals were calcined they 
increased in weight, which they pointed out as due to a certain spirit¬ 
uous nitro-aenus, another name for what we now call oxygen. 
Mayon undoubtedly proved that air was a mixed compound, for he 
stated that when a portion of it was absorbed by the process of cal¬ 
cination an inactive gas remained, and came to the conclusion 
that the act or breathing and combustion were allied phenomena. 
