The Tendencies of Chemistry 



which determined it. The first is also said to 

 cause molecular modification, whereas the 

 second leaves the molecule intact; this view 

 is equally risky, because it would place under 

 the heading of chemistry the modifications 

 of the physical state of water and its anomalies 

 near its point of maximum density. It is thus 

 really impossible to discover an accurate defini- 

 tion at the present day. 



To sum up, chemistry sees its fundamental 

 laws losing their character of absolute necessity 

 and rigorous exactitude. The belief in the 

 existence of simple bodies not transmutable 

 into each other, the law of the conservation 

 of matter and the law of simple ratios, formed 

 the foundations of the structure erected by 

 Lavoisier and his successors. We have seen 

 that for us the last of these laws has lost its 

 originally imperative character. The law of 

 the conservation of matter has, in its turn, been 

 the object of attacks, regarding which it is 

 difficult to form an opinion. Landolt, after 

 weighing with the most minute precautions 

 chemical systems before and after reactions, 

 thought he noticed a systematic variation of 



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