The 
sign, added by Chopin in a proofreading of FE, proves that at the last stage of shaping of the Etude's notation, the composer decided to consolidate this way of interpretation – at least here, for the second time – in spite of the fact that earlier (cf. bar 8) he did not seem to be so adamant. In addition, it is justified by the combination of this crescendo with the preceding it pair of hairpins, suggested by us for the first time, in bar 8. On the other hand, the sound image of the entire section embracing bars 39-53 is clearly different in FE than in FC – the only three dynamic signs appear in FE in bars 44-46. Taking this into consideration, we assume that in the main text, generally based on FC, a possibility of omitting the discussed in bar 46 should be left to the performers.
Compare the passage in the sources»
category imprint: Differences between sources; Corrections & alterations
issues: Authentic corrections of FE
notation: Articulation, Accents, Hairpins