36 POPULAR SCIENTIFIC KNOWLEDGE. 



be presented in language, grave, dignified, and yet animated ; 

 and that those who are able to escape occasionally from the 

 restricted circle of the ordinary duties of civil life, and regret 

 to find that they have so long remained strangers to nature, 

 may thus have opened to them access to one of the noblest 

 enjoyments which the activity of the rational faculties can 

 afford to man. The study of general natural knowledge 

 awakens in us as it were new perceptions wliich had long 

 lain dormant ; we enter into a more intimate communion 

 with the external world, and no longer remain without in- 

 terest or sympathy for that which at once promotes the 

 industrial progress and intellectual ennoblement of man. 



The clearer our insight into the connection of phsenomena, 

 the more easily shall we emancipate ourselves from the error 

 of those, who do not perceive that for the intellectual culti- 

 vation and for the prosperity of nations, all branches of 

 natural knowledge are alike important ; whether the mea- 

 suring and describing portion, or the examination of 

 chemical constituents, or the investigation of the phy- 

 sical forces by which all matter is pervaded. It has not 

 been uncommon presumptuously to depreciate investigations 

 arbitrarily characterised as "purely theoretic;" forgetting 

 that in the observation of a phenomenon which shall at first 

 sight appear isolated, may lie concealed the germ of a great 

 discovery. "When Galvani first stimulated the nervous fibre 

 by the contact of two dissimilar metals, his immediate contem- 

 poraries could not have foreseen that the voltaic pile would 

 discover to us in the alkalis, metals of a silvery lustre, easily 

 inflammable, and so light as to float in water ; that it would 

 become the most important instrument of chemical analysis, 

 and at the same time a therrnoscope and a magnet. When 



