The Unknown.—­I deny in toto the accuracy of what you are advancing.  I have already shown that real philosophers, not labouring for profit, have done much by their own inventions for the useful arts; and, amongst the new substances discovered, many have had immediate and very important applications.  The chlorine, or oxymuriatic gas of Scheele, was scarcely known before it was applied by Berthollet to bleaching; scarcely was muriatic acid gas discovered by Priestley, when Guyton de Morveau used it for destroying contagion.  Consider the varied and diversified applications of platinum, which has owed its existence as a useful metal entirely to the labours of an illustrious chemical philosopher; look at the beautiful yellow afforded by one of the new metals, chrome; consider the medical effects of iodine in some of the most painful and disgusting maladies belonging to human nature, and remember how short a time investigations have been made for applying the new substances.  Besides, the mechanical or chemical manufacturer has rarely discovered anything; he has merely applied what the philosopher has made known, he has merely worked upon the materials furnished to him.  We have no history of the manner in which iron was rendered malleable; but we know that platinum could only have been worked by a person of the most refined chemical resources, who made multiplied experiments upon it after the most ingenious and profound views.  But, waiving all common utility, all vulgar applications, there is something in knowing and understanding the operation of Nature, some pleasure in contemplating the order and harmony of the arrangements belonging to the terrestrial system of things.  There is no absolute utility in poetry, but it gives pleasure, refines and exalts the mind.  Philosophic pursuits have likewise a noble and independent use of this kind, and there is a double reason offered for pursuing them, for whilst in their sublime speculations they reach to the heavens, in their application they belong to the earth; whilst they exalt the intellect, they provide food for our common wants, and likewise minister to the noblest appetites and most exalted views belonging to our nature.  The results of this science are not like the temples of the ancients, in which statues of the gods were placed, where incense was offered and sacrifices were performed, and which were presented to the adoration of the multitude founded upon superstitious feelings; but they are rather like the palaces of the moderns, to be admired and used, and where the statues, which in the ancients raised feelings of adoration and awe, now produce only feelings of pleasure, and gratify a refined taste.  It is surely a pure delight to know how and by what processes this earth is clothed with verdure and life, how the clouds, mists, and rain are formed, what causes all the changes of this terrestrial system of things, and by what divine laws order is preserved amidst apparent