The name of the third river is Hiddekel
A river which ran by Shushan in Persia, and retained its name in the times of Daniel, ( Daniel 10:4 ) where it is called the great river; and it seems it bears the same name now among the Persians; at least it did an hundred and fifty years ago, when Rauwolff F13 travelled in those parts. The Targum of Jonathan here calls it Diglath, the same with the Diglito of Pliny F14; and according to him it is called Tigris, from its swiftness, either from the tiger, a swift creature, or from (arg) , "to dart", in the Chaldee language; and so Curtius F15 says, that in the Persian language they call a dart "tigris": and with this agrees the word "Hiddekel", which in the Hebrew language signifies sharp and swift, as a polished arrow is; and Jarchi says it is so called, because its waters are sharp and swift: though this is contradicted by some modern travellers F16 who say it is a slower stream than the Euphrates, and is not only very crooked, and full of meanders, but also choked up with islands, and great banks of stone:
that is [it] which goeth towards the east of Assyria:
a country which had its name from Ashur, a son of Shem, ( Genesis 10:11 Genesis 10:22 ) it became a famous kingdom and monarchy, Nineveh was the metropolis of it, which was built on the river Tigris or Hiddekel; and, as before observed, it ran by Shushan in Persia; and so, as Diodorus Siculus
and the fourth river [is] Euphrates:
or "Phrat", as in the Hebrew tongue. Reland F19 seems rightly to judge, that the syllable "eu", prefixed to it, is the Persian "au" or "cu", which in that language signifies "water"; so that "Euphrates" is no other than "the water of Phrat", so called from the fruitfulness of it; for its waters, as Jarchi says, fructify, increase, and fatten the earth; and who rightly observes that these names, and so those of other rivers, and of the countries here mentioned, are named by a prolepsis or anticipation, these being the names they bore when Moses wrote; unless it may be thought to be the Hebrew (awh) , "Hu, the, that Phrat"; and which the Greeks have made an "eu" of.
(After the global destruction of Noah's flood, it is doubtful that the location of these rivers could be determined with any degree of certainty today. Ed.)
F13 Travels, part. 2. c. 9. p. 159. ed. Ray.
F14 Nat. Hist. l. 6. c. 27.
F15 Hist. l. 4. c. 9.
F16 De la Valle & Thevenot, apud Universal History, vol. 4. p. 248.
F17 Bibliothec. l. 2. p. 99.
F18 Cartwright's Preacher's Travels, p. 91.
F19 Ut supra, (De Situ Paradisi) p. 45.