If extensive _usefulness_ be the object, science has the same advantage over politics. The greatest success in the latter seldom extends farther than one particular country, and one particular age; whereas a successful pursuit of science makes a man the benefactor of all mankind, and of every age. How trifling is the fame of any statesman that this country has ever produced to that of Lord Bacon, of Newton, or of Boyle; and how much greater are our obligations to such men as these, than to any other in the whole _Biographia Britannica_; and every country, in which science has flourished, can furnish instances for similar observations. Here my reader will thank me, and the writer will, I hope, forgive me, if I quote a passage from the postscript of a letter which I happen to have just received from that excellent, and in my opinion, not too enthusiastical philosopher, father Beccaria of Turin. _Mi spiace che il mondo politico ch'e pur tanto passeggero, rubbi il grande Franklin al mondo della natura, che non sa ne cambiare, ne mancare._ In English. "I am sorry that the _political world_, which is so very transitory, should take the great Franklin from the _world of nature_, which can never change, or fail." I own it is with peculiar pleasure that I quote this passage, respecting this truly great man, at a time when some of the infatuated politicians of this country are vainly thinking to build their wretched and destructive projects, on the ruins of his established reputation; a reputation as extensive as the spread of science itself, and of which it is saying very little indeed, to pronounce that it will last and flourish when the names of all his enemies shall be forgotten. I think it proper, upon this occasion, to inform my friends, and the public, that I have, for the present, suspended my design of writing _the history and present state of all the branches of experimental philosophy_. This has arisen not from any dislike of the undertaking, but, in truth, because I see no prospect of being reasonably indemnified for so much labour and expence, notwithstanding the specimens I have already given of that work (in the _history of electricity_, and of the _discoveries relating to vision, light, and colours_) have met with a much more favourable reception from the best judges both at home and abroad, than I expected. Immortality, if I should have any view to it, is not the proper price of such works as these.