396 



NATURE 



\Atigust 25, 1881 



and the same element or atomic molecale existing in different 

 conditions of movability. The essential unity of matter is an 

 hypothesis in harmony with the equal action of gravity upon all 

 bodies." I now come to Sir Benjamin Brodie, whom we have 

 so lately lost, the last of the great English triumvirate to whom 

 I mean to refer. His views I have already stated in his own 

 words, but I may here again state that as early as 1867, 



almost, we may say, before the spectroscope had been applied to 

 the sun, except in the general way, which was started by Fraun- 

 hofer and Kirchhoff, he prophesied that the solar facts would 

 be as I think we have found them. That is to say, he stated 

 his belief that at the solar temperature the constituents of our 

 elementary bodies would be found exi-.ting in independent forms. 

 The greatest chemical philosopher now living, M. Dumas, so 



Pedigree of the Indo-Germanic Languages. 



Anglo-Saxons. High-Germans. 



Ancient Prussians 



Letts, 



i 



Low-Germans. 



Ancient .'^axons. 



Baltic Races. Saxons. Fr 



1 I 



I 

 Sorbians. Scaiidinavi.ans. Low-Germans. 



I Goths. I 



West Sclaves. 



South 

 Sclaves, 



South-East Sclaves. 



Sclaves. 



I 



Germans. 



\ 



Primitive Germans. 



Sclavo-Letts. 



Ancient Scotch. 



Romans. 



Ancient British. 



Gauls. 



Sclavo-Germans. 



Albanese. Greelis. 



Primitive 

 Thracians. 



Indians. Iranians. 



Gr.Tco- Romans 



Indo-Germanic. 



long ago as 1836 published a series of lectures in which his views 

 were very clearly stated indeed, and any one who reads them 

 will see how convinced he was then of the considerable amount 

 of evidence that had already been accumulated in favour of the 

 non-elementary nature of a great number of substances then 

 classed as elements. 



Then again we can pass to another chemical philosopher, 

 Kopp. In his researches on specific heats he also gives evidence 



to show that that relationship is not to be depended upon to esta- 

 blish the received view. If, then, the three greatest English 

 chemists we can name, and the most eminent chemical philoso- 

 phers in France and Germany, give their opinion in behalf of 

 the compound nature of the chemical elements, can these simpler 

 forms be any other than those we detect by means of the spec- 

 troscope? By the conditions of the problem and the absence of 

 knowledge they are not decomposable in the laboratory ; if they 



