M. Arago, in his brilliant eloge on Fourier, observes:—"The ancients had a taste, or rather a passion, for the marvellous, which made them forget the sacred ties of gratitude. Look at them, for instance, collecting into one single group the high deeds of a great number of heroes, whose names they have not even deigned to preserve, and attributing them all to Hercules. The lapse of centuries has not made us wiser. The public in our time also delight in mingling fiction with history. In all careers, particularly in that of the sciences, there is a design to create Herculeses. According to the vulgar opinion, every astronomical discovery is attributable to Herschel. The theory of the motions of the planets is identified with the name of Laplace, and scarcely any credit is allowed to the important labours of D'Alembert, Clairaut, Euler, and Lagrange. Watt is the sole inventor of the steam-engine, whilst Chaptal has enriched the chemical arts with all those ingenious and productive processes which secure their prosperity." To countervail this error, Arago continues: "Let us hold up to legitimate admiration those chosen men whom nature has endowed with the valuable faculty of grouping together isolated facts, and deducing beautiful theories from them; but do not let us forget that the sickle of the reaper must cut down the stalks of corn, before any one can think of collecting them into sheaves."