BOOK VI. 



CHAPTER I. 



Air and Exercise. 



" If all the capacities of all ages should unite and transmit 

 their labours, no great progress would be made in learning by 

 anticipations ; because the radical errors, and those which occur 

 in the first process of the mind, are not cured by subsequent 

 means and remedies. An instauration must be made from the 

 very foundation, if we do not wish to revolve for ever in a circle, 

 making only some slight and contemptible progress." BACON. 



FROM the earliest periods of history the ancients 

 confounded air with heat, which they regarded 

 as the great spirit of the universe. For example, 

 the Greek word arjp, and the Latin aura, were 

 evidently derived from T)K aur* which, in the 

 Hebrew, Phoenician, Egyptian, and Chaldean 

 languages, signified light, fire, and spirit. In 

 the Treatise of Hippocrates on Air, he maintains 



* The " aura particula Divina " of Cicero, Adrian, and 

 other Roman philosophers, was certainly not gross air, but what 

 Pope very beautifully terms " vital spark of heavenly flame," 

 which was called aura, because it is obtained from the air by 

 breathing. The Latin word spiritus also means air or breath, 

 and inspire to breathe in air, from which the vital spirit is 

 derived. Hence the origin of our English words spirit and 

 inspiration. 



