THE EARLY DAYS OF CHEMISTRY 5 



taken from the writings of, those who lived at a very 

 remote time from the present day, but only six or seven 

 generations ago, that our great-great-great-grandfathers 

 differed from ourselves not merely in lack of knowledge, 

 but in the way they regarded the facts which they 

 observed. And it is consequently somewhat difficult for 

 us to adopt their point of view, and to think their 

 thoughts. But we must attempt to do so, if we are to 

 realise the progress of our science. 



The progress of the science of Chemistry, indeed, forms 

 one phase of the progress of human thought. The ideas 

 which have been held, however, run in certain channels. 

 They may all be referred to speculations on the nature 

 of matter ; but the speculations take different forms. 

 For it may be inquired : What forms is matter capable of 

 assuming ? Or, what is the minute structure of matter ? 

 Or, what changes does matter undergo ? These three 

 questions were for the ancients, as they are still for us, 

 fundamental; and it will be the aim of these essays to 

 endeavour to give the reader some idea of the history 

 of these three lines of thought. We shall see that 

 our present knowledge enables us in some measure 

 to connect these three lines of inquiry by virtue of 

 certain hypotheses ; but it will be convenient to treat 

 of each separately, at least up to a certain stage. 



THE ELEMENTS 



The word 'Element/ in the old days, had a meaning 

 different from that which we now ascribe to it ; or, to be 

 more exact, it had two meanings, which were frequently 

 confounded with one another. The suggested derivation 

 of the word indicates one of these meanings ; it is that 

 which we usually give it ; for, just as ' 1,' ' m,' and ' n ' are 



