GRADUM, AD, or GRADUS, AD. The Maritime Itin. of the south coast of Gallia makes it a distance of 16 M. P., a fossis ad gradum Massilitanorum fluvius Rhodanus;and then 30 M. P. a gradu per fluvium Rhodanum Arelatum.The Fossae are the Fossae Marianae ( Foz-les-Martigues), and ad gradummust be one of the old mouths of the Rhone. The site of ad gradumis supposed by some French writers to be Galejon. Ammianus Marcellinus (Ammian. 15.11) describes the Rhone as entering the sea per patulum sinum quem vocant Ad Gradus.There may have been several Gradus at the mouths of the Rhone, for gradusis a landing-place, or steps for getting in and out of ships (Valer. Max. 3.6); and D'Anville observes that the name Gradus is not limited to the mouths of the Rhone, but occurs on the coasts of Spain and Italy, where it is pronounced Graoand Grado. Ammianus places this sinus18 miles from Aries, which is a great deal too little. The word scala,a Latin word of the same meaning, adopted by the Greeks, is also used to signify a landing-place or maritime town in the eastern part of the Mediterranean.
[G.L]