TRANSACTIONS OF SECTION B. 599 



Quick, restless, imaginative, he sprang from discovery to discovery. With extra- 

 ordinary acuteness and powers of invention, he lacked the steady purpose of 

 Boyle, the calm judgment and completeness of Newton — his two great scientific 

 contemporaries. It might be said of Hooke, as was said of a great poet, he 

 touched nothing he did not strike fire from ; and some would add that his touch 

 had the same effect on persons as on things. We can hardly name a discovery 

 of this age which Hooke had not in part anticipated and claimed as his own. 

 Like a prospector in a newly discovered mining district, he hurried from spot to 

 spot, pegging in his claims and promising to return to work out the ore. And 

 what rich lodes he struck ! The particular claim we are concerned with here is 

 the discovery of the relation between air and flame. In 1665 Hooke published 

 in the ' Micrographia ' a description of flame and the phenomena of combustion 

 which in my judgment has never been surpassed. How far he was indebted to 

 Boyle will appear directly. 



Born in 1635, Hooke spent five years at Westminster School, then under 

 Dr. Busby, and proceeded to Christ Church in 1653. At school and college it is 

 related of him that he devoted his time to designing flying machines. These 

 mechanical inventions attracted the notice of Dr. Wilkins, Warden of Wadham, 

 and a leading member of the Philosophical Society. This led to his introduction 

 to Dr. Willis, to whom he became assistant in chemistry and natural philosophy. 

 Willis recommended him to Boyle, whose assistant he became. His first work in 

 Boyle's laboratory was the construction of the improved air-pump. In 1662 

 Boyle obtained for him the position of curator of experiments in the London 

 Society, soon to be known as the Royal Society. Hooke was thus Boyle's 

 assistant when those experiments on combustion I have described were being 

 carried on. Among other experiments made by Boyle were some on the dis- 

 tillation of wood in retorts. 



' Having sometimes distilled such woods as box, whilst our caput mortuum 

 [i.e., the residue] remained in the retort it continued black liije charcoal, though 

 the retort were kept red hot in a vehement fire; but as soon as ever it was 

 brought out of that vessel into the open air the burning coals would degenerate 

 or fall asunder into pure white ashes.' ^ Hooke saw the experiment and a new 

 light flashed on him. 'From the experiment of charring coals,' he writes, 

 ' (whereby we see that, notwithstanding the great heat, the solid parts of the 

 wood remain, whilst they are preserved from the free access of the air, undissi- 

 pated) we may learn that which has not been published or hinted, nay, not so 

 much as thought of by any ; and that in short is this : — 



' That the air is the imiversal dissolvent of all sulphurous [i.e., combustible] 

 bodies. . . . 



* That this action of dissolution produces a very great heat, and that which we 

 call fire. 



' That this action is performed with so great a violence, and does so rapidly 

 agitate the smallest parts of the combustible matter, that it produces in the 

 diaphanous medium of the air the action, or pulse oi Light. 



' That this dissolution is made by a substance inherent and mixed with the 

 air, that is like, if not the very same with, that which is mixed in saltpetre. 



' That the dissolving parts of the air are but few . , . whereas saltpetre is a 

 menstruum . . . that abounds more with these dissolvent particles. 



' It seems reasonable to think that there is no such thing as an element of 

 fire, . . . but that that shining transient body which we call flame is nothing 

 else but a mixture of air and volatile parts of combustible bodies, which are 

 acting upon one another whilst they ascend; which action , . . does further 

 rarifie those parts that are acting or are very near them, whereby they, growing 

 very much lighter than the heavy parts of that menstruum that are more remote, 

 are thereby protruded and driven upwards.' 



Hooke quotes no other experiments in support of his theory of flame. He 

 states that he has made many ; he has, however, only time * to hint an hypo- 



' The Sceptical Chemist. 



