1 6 MATTER, LIVING FORCE AND HEAT, 



velocity and living force. When, again, by the application 

 of cold we condense the steam into water, and by a further 

 abstraction of heat we bring the water to the solid condition 

 of ice, we witness the repetition of similar phenomena in 

 the reverse order. The particles of steam, in assuming the 

 condition of water, fall together through a certain space. 

 The living force thus produced becomes converted into heat, 

 which must be removed before any more steam can be 

 converted into water. Hence it is always necessary to 

 abstract a great quantity of heat in order to convert steam 

 into water, although the temperature will all the while 

 remain exactly at 21 2° ; but the instant that all the steam 

 has been condensed, the further abstraction of heat will 

 cause a diminution of temperature, since it can only be 

 employed in diminishing the velocity of revolution of the 

 atoms of water. What has been said with regard to the 

 condensation of steam will apply equally well to the con- 

 gelation of water. 



" I might proceed to apply the theory to the phenomena 

 of combustion, the heat of which consists in the living force 

 occasioned by the powerful attraction through space of the 

 combustible for the oxygen, and to a variety of other 

 thermo-chemical phenomena ; but you will doubtless be 

 able to pursue the subject further at your leisure. 



"I do assure you that the principles which I have very 

 imperfectly advocated this evening may be applied very 

 extensively in elucidating many of the abstruse as well as 

 the simple points of science, and that patient inquiry on 

 these grounds can hardly fail to be amply rewarded." 



In order to duly appraise work, it is necessary to realise 

 the obstacles overcome, and this may be very difficult. To 



