"It has lengthened life; it has mitigated pain; it has extinguished diseases; it has increased the fertility of the soil; it has given new securities to the mariner; it has furnished new arms to the warrior; it has spanned great rivers and estuaries with bridges of form unknown to our fathers; it has guided the thunderbolt innocuously from heaven to earth; it has lighted up the night with the splendor of the day; it has extended the range of the human vision; it has multiplied the power of the human muscles; it has accelerated motion; it has annihilated distance; it has facilitated intercourse, correspondence, all friendly offices, all despatch of business; it has enabled man to descend to the depths of the sea, to soar into the air, to penetrate securely into the noxious recesses of the earth, to traverse the land in cars which whirl along without horses, and the ocean in ships which run ten knots an hour against the wind."[299] The first was consumed in solving unsolvable enigmas, fabricating portraits of an imaginary sage, mounting from hypothesis to hypothesis, tumbling from absurdity to absurdity; it despised what was practicable, promised what was impracticable; and because it disregarded the limits of the human mind, ignored its power. The other, measuring our force and weakness, diverted us from roads that were closed to us, to start us on roads that were open to us; it recognized facts and laws, because it resigned itself to remain ignorant of their essence and principles; it rendered man more happy because it has not pretended to render him perfect; it discovered great truths and produced great effects, because it had the courage and good sense to study small things, and to keep for a long time to petty vulgar experiments; it has become glorious and powerful, because it deigned to become humble and useful. Formerly, science furnished only vain pretensions and chimerical conceptions, whilst it held itself far aloof from practical existence, and styled itself the sovereign of man. Now, science possesses acquired truths, the hope of loftier discoveries, an ever-increasing authority, because it has entered upon active existence, and has declared itself the servant of man. Let it keep to its new functions; let it not try to penetrate the region of the invisible; let it renounce what must remain unknown; it does not contain its own issue, it is but a medium; man was not made for it, but science was made for man; it is like the thermometers and piles which it constructs for its own experiments; its whole glory, merit, and office, is to be an instrument: