PREFACE.

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...still unexplored, and even provided the Scholars original: "Sçavans"; the learned academics and members of scientific societies in the 18th century. with new subjects for exercising their sagacity. It would be only just that these latter, in their turn, should provide the former with maxims to allow them to act with greater precision. In whatever class one is placed, we must all work together for the good of Society; this is an indispensable duty which ought to be the primary quality of a good Citizen.

If one were entitled to accuse those who conduct the works that interest the State original: "l'Etat"; here referring to public infrastructure projects like bridges, canals, and fortifications funded by the crown. of a little negligence, this reproach should mainly concern the young men who—little moved by the duties of the path they have chosen—affect to exalt practice to the contempt of theory, hoping thereby to justify their lack of taste for study. But do they truly know this practice to which they wish to limit themselves? They can have only a confused sense of it; without experience and without making use of their judgment, do they know what course must be taken in the difficult cases that may arise? Occupied by frivolous objects, they maintain themselves in a state of mediocrity without making it their duty to acquire distinction, and without reflecting that one learns very slowly when one only learns things when necessity obliges us to consider them.

Furthermore, it would be a great abuse to take advantage of the example of their predecessors, who nonetheless made themselves commendable by such a long road; if they had had the same assistance as is available today, there is no doubt they would have made better use of it, and I want no other proof than the merit of having drawn almost entirely from their own resources what they acquired.

If many people think that Mathematics is of little use for rectifying practice, this comes from two causes. The first is that they wish to limit the extent of a Science they do not know. The se—