AUTOBIOGRAPHY OF FRANCIS ARAGO. 147 



the next day, that IM. Eaynal read with advantage the " Hydraulic Archi- 

 tecture" of Prony, the " Mecanique Analytique," and the " Mecauique 

 Celeste." This excellent man often gave me useful advice ; but I must 

 say that I found my real master in the cover of M. Garnier's " Treativse 

 on Algebra." This cover consisted of a printed leaf, on the outside of 

 which blue paper was pasted. The reading of the page not covered 

 made me desirous to l^now what the blue paper hid from me. 1 took oft" 

 this paper carefully, having first damped it, and was able to read under- 

 neath it the advice given by d'Alembert to a young man who communi- 

 cated to him the difliculties which he met with in his studies : " Go on, 

 sir, go on, and conviction will come to you." 



This gave me a gleam of light; instead of persisting in attempts to 

 comprehend at first sight the propositions before me, I admitted their 

 truth provisional!}'. I went on farther, and was quite surprised, on the 

 morrow, that I comprehended perfectly' what over-night appeared to me 

 to be encompassed with thick clouds. 



I thus made myself master, in a year and a half, of all the subjects 

 contained in the i^rogramme for admission, and I went to Montpellier 

 to undergo the examination. I was then sixteen years of age. M. Monge, 

 jr., the examiner, was detained at Toulouse by indisposition, and wrote 

 to the candidates assembled at Montxiellier that he would examine them 

 in Paris. I was myself too unwell to undertake so long a journey, and 

 I returned to Perpignan. 



There I listened for a moment to the solicitations of my family, who 

 pressed me to renounce the prospects which the Polytechnic School 

 opened. But my taste for mathematical studies soon carried the day. 

 I increased my library with Euler's "Introduction a I'Analyse Infinitesi- 

 male," with the " Eesolution des Equations Numeriques," with Lagrange's 

 " Theorie des Fonctions Aualytiques," and " Mecanique Analytique," and 

 finally with Laplace's " Mecanique Celeste." I gave myself up with great 

 ardor to the study of these books. From the journal of the Polytechnic 

 School, containing such investigations as those of M. Poissou on Elimi- 

 nation, I imagined that all the pupils were as much advanced as this 

 geometer, and that it would be necessary to rise to this height to suc- 

 ceed. 



From this moment I prepared myself for the artillery service, the 

 aim of my ambition ; and as I had heard that an officer ought to under- 

 stand music, fencing, and dancing, I devoted the first hours of each day 

 to the cultivation of these accomplishments. 



The rest of the time I was seen walking in the moats of the citadel of 

 Perpignan, seeking by more or less forced transitions to pass from one 

 question to another, so as to be sure of being able to show tlie examiner 

 how far my studies had been carried.* 



* Mdchain, iiicmber of the Academy of Sciences aud of tlie lustitntc, was charged 

 in 1792 with the piolongatiou of the measure of the arc of the mcx-idian iu Spaiu, as I'ar 

 as Barcelona. 



Duriug his operations iu the Pyrenees, iu 1794, he had known my father, who was 



