The 1786 article Memoirs of Baron de Tott in The Monthly Review volume 73 says:
> Herodotus, in calling Egypt the Gift of the Nile *
and gives the original Greek text in a footnote at the bottom of page 246
There is a further explanation in Hecataeus and Herodotus on "A Gift of the River" _Journal of Near Eastern Studies_ Vol. 25, No. 1 (Jan., 1966), pp. 57-61
According to this article, which provides a much more complete quotation, the meaning is not the whole of Egypt, but the delta. The river created the land of the Nile delta.