Looking for an André Weil excerpt I just wasted the last hour on google looking in vain for an excerpt of Weil's writings describing the process of discovering mathematics.  I believe he once beautifully described the feeling of loss that accompanies the realization that the discovery you made seems, in retrospect, trivial.  Am I misremembering or just bad at googling?  Thanks for your help.
 A: You might have the following passage in mind:

It appears in A. Weil, De la métaphysique aux mathématiques, Science 60, p. 52–56 (see also Collected Papers II, p. 406–412). The excerpt and the reference are taken from a preprint of A. Borel on A. Weil, scan available here (from A. Knapp's homepage).
Edit: As Bill pointed out in his answer below, this preprint is published:


*

*In the Proceedings of the American Philosophical Society,
Vol. 145, No. 1 (Mar., 2001), pp. 107–114 (jstor-link, may be behind a paywall).

*Reprinted and freely available as Mathematical Perspectives — André Weil Bull. Amer. Math. Soc. 46 (2009), 661–666. 


Added: For further elaborations and context, I strongly recommend to read both, Borel's article I linked to and Weil's original, as well as Weil's 1940 letter to his sister Simone Weil.
While I'm at it, I cannot refrain from insisting that you read The Apprenticeship of a Mathematician—preferably in its French original Souvenirs d'apprentissage—in case you haven't done so already.
A: Having aleady OCRed Borel's article on Weil (see Theo's reply), I cannot resist posting a larger excerpt here, since it provides much further context that I suspect will help readers to better appreciate Weil's "search for elegance, beauty and hidden harmonies". Perhaps it will help motivate some readers to join in such fruitful endeavors. I too strongly endorse the literatured cited by Theo. It can prove highly inspirational to budding mathematical minds.
Edit: I just noticed that the AMS has a nicer typeset version of Borel's article from 2009 BAMS.

His output offers an extraordinary combination of foundational work, to secure a solid 
  basis in some area, of often decisive contributions at the cutting edge, solving old or new 
  problems, and of forays into unknown territory, in the form of problems or conjectures, 
  guided by a seemingly infallible sense for the directions into which one should forge ahead. 
Of course, I feel quite uncomfortable in making such a statement without backing it up 
  in any way, so allow me to turn to the mathematicians to give an idea of these facets of his 
  output in at least one area, algebraic geometry. The theorem he had proved in 1940 (see 
  above) relied on some facts of algebraic geometry for some of which there was no solid 
  reference. Moreover, the development of algebraic geometry, from "classical" (i.e. projective 
  or affine complex varieties) to "abstract" (varieties over arbitrary fields), was also crying out 
  for reliable foundations. It took him several years to supply them in a massive (and rather 
  arid) treatise "Foundations of algebraic geometry" (1946), the only comprehensive basis for 
  algebraic geometry for a number of years. Although dealing with a very general "abstract 
  situation", he developed it in part in analogy with the theory of differentiable manifolds in 
  differential geometry, and also with some constructions in algebraic topology. It was 
  followed, among other items, by a monograph proving in full his 1940 result, by foundations 
  for abelian varieties, fibre bundles in algebraic geometry, algebraic groups, the advocacy of 
  the use of analytic fibre bundles in several complex variables, and in 1949, in a short Note, 
  by a series of conjectures (soon called the Weil conjectures) which were to have an enormous 
  impact on algebraic geometry. In particular, he postulated the existence of a cohomology 
  theory in this set up, with properties allowing one to transcribe known arguments in algebraic 
  topology, such as the Lefschetz fixed point theorem, a bold idea, unique to him, way ahead of 
  its time. It was implemented some ten years later by A. Grothendieck (etale cohomology), 
  and it took twenty-five years before Deligne proved the last, and by far hardest, of these 
  conjectures, with far reaching consequences, not yet exhausted. 
So far, I have said little of what has arguably been Weil's most abiding interest in 
  mathematics: "Zeta functions". The first one was used by B. Riemann in 1857 to study the 
  distribution of prime numbers among positive integers. The "Riemann hypothesis" about the 
  zeroes of this function is still unproved and generally viewed as the Holy Grail of 
  mathematics. The introduction of this function to study the discrete (the integers) in a 
  continuous framework (real or complex numbers) was quite revolutionary and proved to be 
  immensely fruitful. Zeta functions, with corresponding Riemann hypotheses, have proliferated 
  in analysis, algebraic geometry and number theory, and have always been on Weil's mind. 
  (His 1940 theorem dealt with one kind and his 1949 conjectures with generalizations of it.) 
  He was convinced that the problem of the Riemann hypothesis, even in the original case, had 
  to be attacked broadly. How broadly can be only explained in mathematical terms of course, 
  but he drew an analogy with the Rosetta Stone, which seems to me so typical of his thought 
  processes and of the aesthetic component in his approach to mathematics that I cannot resist 
  trying to give an idea of it, as imprecise as it has to be. It is developed in a short article: De
  la metaphysique aux mathematiques, (From metaphysics to mathematics), Science 1960, 52-56; 
  Collected Papers II, 406-412. 
"Metaphysics", he explains, is meant here in the sense of the 18'th century 
  mathematicians, when they spoke of, say, "the metaphysics of the theory of equations": 

"... a collection of vague analogies, difficult to grasp and difficult to formulate, 
        which nevertheless appeared to them to play an important role at certain 
        moments in the research and discovery in mathematics". 

and then he elaborates. 

"Nothing is more fecund, all the mathematicians know it, than those obscure 
        analogies, the blurred reflections from one theory to another ... nothing gives 
        more pleasure to the researcher. One day the illusion drifts away, the 
        premonition changes to a certitude: the twin theories reveal their common 
        source before disappearing; as the Gita teaches it, knowledge and indifference 
        are reached at the same time. The metaphysics has become mathematics, ready 
        to form the subject matter of a treatise, the cold beauty of which cannot move 
        us anymore." 

Further: 

"Fortunately for researchers, as the fogs clear away on some point, they 
        reappear on another. A major part of the Tokyo Colloquium [1955] was 
        devoted to the analogies between number theory and the theory of algebraic 
        functions. There we are still fully in metaphysics..." 

"Algebraic functions" alludes here to a theory built up by Riemann by analytical, 
  transcendental means. To link it to number theory, guided by "obscure analogies", is a 
  problem which had fascinated Weil early on (as already hinted by the title of his Thesis), and 
  he felt that progress was still scant by 1960. Meanwhile, a third topic had appeared: 
  "algebraic curves over finite fields" (the subject matter of his 1940 theorem), which was 
  easier to relate to the other two and thus served as an intermediary. These items and many 
  generalizations or related results formed an enormous amount of mathematics naturally 
  divided into three parts, each with its own framework, (in brief, transcendental, arithmetic and 
  algebraico-geometric) and techniques. As Weil puts it, we are faced with a text in three parts 
  (he calls them columns), each written in its own language, called by him Riemannian, 
  arithmetic and Italian respectively, in analogy with the Rosetta Stone. However, there is an 
  huge difference: the latter contains the same text in the three languages (or rather, assuming 
  this, Champollion was able to decipher Egyptian hieroglyphic writing), while we have here 
  only in each column fragments of what is hoped to be similar texts, once completed. 
The task of the mathematicians, then, is to add translations of a given fragment into 
  the other columns, to transform those obscure analogies into mathematics, and eventually 
  build a dictionary which would allow one to pass from one column to the others. If it were 
  sufficiently complete, then the Riemann hypothesis would be proved, Weil 
  concludes, wondering how long mathematics will have to wait for a Champollion. 
As an illustration of his outlook, let me mention a paper ([1972], p. 249-64, in his 
  Collected Papers III), where he formulates a statement in "Riemannian" language, the truth of 
  which would imply that of the Riemann hypothesis (for many zeta functions), points out that 
  it has an analogue in "Italian" which, in view of his earlier work, is a proven theorem, and 
  comments that this provides for him, perhaps, the strongest evidence in favor of the original 
  Riemann hypothesis, one of many examples of his unshakable belief in the unity and harmony 
  of mathematics. 
Weil was indeed fluent in the three languages and many of his works can be 
  interpreted as contributions to the dictionary, but not all, though. In particular, as befits a 
  man with his cultural interests, he had a strong commitment to the history of mathematics, 
  which culminated in a history of number theory from 1800 B.C. to 1800 A.D. (from 
  Hammurapi to Legendre). Much earlier it had been at the origin of the Historical Notes in 
  Bourbaki, to which he was a main contributor until he retired. 
As a mathematician, his work shows him to be at the same time an architect, a builder 
  and a poet: an architect for fostering a global view of mathematics and striving to display its 
  fundamental unity, a builder by his specific, often decisive, contributions to a great variety of 
  topics and a poet by his search for elegance, beauty and hidden harmonies. 
ARMAND BOREL
  Professor Emeritus
  School of Mathematics
  Institute for Advanced Study
  Princeton, NJ 08540  

