IN THE ORDINARY AFFAIRS OF LIFE. 35 



necessities or his enjoyments. The mixture of two gases having 

 opposite properties, which forms the atmosphere, is essential to 

 conscious natural existence ; the chemical combination of one 

 of these gases with a third aeriform body forms the water 

 without the presence of which that atmosphere would be irre- 

 spirable, and the human body an inert mass : an affection of 

 matter perpetually excited by the sun, aud adapted to reception 

 in our visual organs, is the means by which the forms and 

 colours, and through them the distances and magnitudes, of 

 created objects are made known to our delighted perceptions. 



To be acquainted with this world of nature must therefore 

 be essential to human happiness. -Man does not possess the 

 instinctive perceptions of the brute creation, which would have 

 been incompatible with that analytical thought, by the exercise 

 of which he acquires his noblest distinctions. He must obtain a 

 rational knowledge of the beings which are subject to his use, 

 and of those, also, which, when uncontrouled, are destructive 

 of his comfort. And in fact the stock of knowledge which 

 every one, from the infant savage to the hoary chief of the 

 tribe, and from the unlettered peasant to the profound philo- 

 sopher, insensibly acquires, for self-protection, and as a ground 

 for the acquisition of knowledge of higher importance, is of 

 this kind. It is a part of the Knowledge of Nature. The know- 

 ledge which leads man to refrain from contact with fire, and 

 from precipitating himself into the waters ; that which induces 

 him to screen himself from the wind by the erection of a wall, 

 and to keep off' the rain by extending a roof from that wall ; 

 all this is a part of the knowledge of nature. 



But it is not this degree only of acquaintance with natural 

 things, which is required by man, when arrived at a state of 

 refined existence. It then becomes necessary, not merely for 

 his happiness as a refined being, but for his very existence in 

 that state, that he should acquire a knowledge of the intimate 

 nature and properties, not only of the objects of creation imme- 

 diately surrounding or affecting him, but of those also which 

 are remote and beyond his direct controul ; and in propor- 

 tion to his advancement in Civilization will be the extent and 

 the elevation of the " Knowledge " he will be required to pos- 

 sess, and to wield as " Power " over the boundless domain 

 which has been committed to his authority. 



To proceed, however, from argument to illustration. The 

 preservation of life is the first object with every man. But he 

 may be deprived of life, to review but a minute fraction of 

 the sources of that deprivation which surround him, either 

 when inhaling "the vital air," by a noxious quality imparted 

 to it by another gaseous substance, in undue quantity ; by 



D 2 



