INTRODUCTION TO THE AMERICAN EDITION. THAT the PRINCIPIA of Newton should have remained so gen erally unknown in this country to the present day is a somewhat remarkable fact ; because the name of the author, learned with the very elements of science, is revered at every hearth-stone where knowledge and virtue are of chief esteem, while, abroad, in all the high places of the land, the character which that name recalls is held up as the noblest illustration of what MAN may be, and may do, in the possession and manifestation of pre-eminent intellectual and moral worth ; because the work is celebrated, not only in the history of one career and one mind, but in the history of all achievement and human reason itself; because of the spirit of inquiry, which has been aroused, and which, in pursuing its searchings, is not always satisfied with stopping short of the foun tain-head of any given truth ; and, finally, because of the earnest endeavour that has been and is constantly going on, in many sections of the Republic, to elevate the popular standard of edu cation and give to scientific and other efforts a higher and a better aim. True, the PRINCIPIA has been hitherto inaccessible to popular use. A few copies in Latin, and occasionally one in English may be found in some of our larger libraries, or in the possession of some ardent disciple of the great Master. But a d^ad language in the one case, and an enormous price in both, particularly in that of the English edition, have thus far opposed very sufficient obstacles to the wide circulation of the work. It is now, how ever, placed within the reach of all. And in performing this la bour, the utmost care has been taken, by collation, revision, and otherwise, to render the First American Edition the most accurate and beautiful in our language. u Le plus beau monument que l? on puisse clever a la gloire de Newton, c'est une bonne edition de ses ouvrages :" and a monument like unto that we would here