NEW CONCEPTIONS IN SCIENCE 



His ideas were simple, his methods rigorous and 

 direct. 



When a chemical combination takes place, when, 

 for example, the two gases, hydrogen and oxygen, 

 are exploded to form water, there is an evolution 

 of heat. A few singular and perplexing excep- 

 tions require explanation ; they seem to be due to 

 changes of the physical state, to condensation, for 

 example, where the amount of heat absorbed out- 

 values the heat evolved by the purely chemical 

 effect. This, at least, is M. Berthelot's idea, and 

 it is to be said that unless some such view be 

 accepted, these curious anomalies would bowl over 

 all our mechanical conceptions of the material 

 world. This deviation remarked, the rule holds 

 good. 



The quantity of heat generated can be measured. 

 For this the calorimeter was invented. M. Ber- 

 thelot's calorimetric bomb has been a device of 

 great value. There have been other workers in 

 this field, but their labors seem slight beside the 

 thirty years of uninterrupted toil of this inde- 

 fatigable man. His work was summed up in two 

 massive volumes which appeared in 1879, bearing 

 the title of Chemical Mechanics, Based on Thermo- 

 chemistry. A year or so ago, a second two volumes 

 of yet more monumental proportions saw the day. 

 It is an encyclopaedia of the subject. 



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