THE BELFAST ADDRESS. 157 



with the steam-engine, he would have taken it, instead 

 of a fall of water, as his motive power. He would have 

 shown the perfect analogy which exists between the 

 oxidation of the food in the body, and that of the coal 

 in the furnace. He would assuredly have anticipated 

 Mayer in calling the blood which the heart diffuses, 

 * the oil of the lamp of life/ deducing all animal mo- 

 tions from the combustion of this oil, as the motions 

 of a steam-engine are deduced from the combustion of 

 its coal. As the matter stands, however, and con- 

 sidering the circumstances of the time, the boldness, 

 clearness, and precision, with which Descartes grasped 

 the problem of vital dynamics constitute a marvellous 

 illustration of intellectual power.* 



During the Middle Ages the doctrine of atoms 

 had to all appearance vanished from discussion. It 

 probably held its ground among sober-minded and 

 thoughtful men, though neither the church nor the 

 world was prepared to hear of it with tolerance. Once, 

 in the year 1348, it received distinct expression. But 

 retractation by compulsion immediately followed; and, 

 thus discouraged, it slumbered till the seventeenth 

 century, when it was revived by a contemporary and 

 friend of Hobbes of Malmesbury, the orthodox Catho- 

 lic provost of Digne, Gassendi. But, before stating 

 his relation to the Epicurean doctrine, it will be well to 

 say a few words on the effect, as regards science, of the 

 general introduction of monotheism among European 

 nations. 



' Were men/ says Hume, ' led into the apprehen- 

 sion of invisible intelligent power by contemplation 

 of the works of Nature, they could never possibly en- 

 tertain any conception but of one single Being, who be- 



*Soo Huxley's admirable 'Essay on Descartes.' 'Lay Ser- 

 mons' pp. 304, 365. 



