A CENTURY OF CHEMISTRY. 113 



Bojle spoke of " one universal matter common to all 

 bodies ; " Dalton said, " We do know that any of 

 the bodies denominated elementary are absolutely 

 indecomposable ; '' Graham suggested as conceivable, 

 " that the various kinds of matter now recognised as 

 different elementary substances may possess one and 

 the same ultimate or atomic molecules existing in 

 different conditions of movement." * Many other 

 examples might be given, and we have already re- 

 ferred to the views of Prout, Meinecke, and Thomas 

 Thomson that there is an ultimate relation between 

 hydrogen and the other elements. 



In 1888-9 Sir William Crookes again raised the 

 question whether what are called elements may not 

 be compounds, and whether all may not have arisen, 

 by gradual condensation, from hypothetical primitive 

 material which he called protyle. 



Accepting the suggestion that substances now 

 thought to be elements may turn out to be com- 

 pounds, Lockyer has pictured the possible dissocia- 

 tion of the elements in the fervent heat within the 

 sun's atmosphere. It may be so, but there are no 

 certain facts as yet which alleviate the hypothetical 

 character of these imaginings ; and it seems well to 

 emphasise that Mendelejeff has expressly dissociated 

 his periodic law from speculations as to the deriva- 

 tion of the elements from one prime matter. 



CO-OPERATIOIS' OF CHEMISTRY AND PHYSICS. 



'No two sciences have entered into a co-operation so 

 close as that which now exists between chemistry and 

 physics. In a way the alliance is almost ancient, for 

 chemistry first became an exact science by adopting 



* See Sir Henry Roscoe's Pres. Address, Rep. Brit. Ass. 

 for 1887, p. 8, 



8 



