"Nile water had always played an important role in the cults of Sarapis-Osiris and Isis. Both he and Isis were believed to summon or have control over the Nile flood. Hellenistic sanctuaries to both deities, as well as a single Roman one, were outfitted with water crypts which functioned as Nilometers, meant to symbolically reproduce the Nile flood and thereby demonstrate the power of both gods. Yet during the 1st centuries B.C. as well as A.D., these Nilometers disappeared, to be replaced by Nile water pitchers, so-called Osiris Hydreios statues (depicting the god as a water-filled jar) and funerary inscriptions of devotees of the cult petitioning Osiris to give them ‘cool water’ in the afterlife."
- Stephan Penders (2012), Imperial waters. Roman river god art in context, Master's Thesis
Penders cites Wild (1981) "Water in the Cultic Worship of Isis and Sarapis".
The Egyptian tetradrachm that I am featuring today shows Osiris Hydreios on the reverse - similar to this statue from Hadrian's villa (Vatican inventory no. 22852). It is solid green basalt, and only symbolically carries water.
[Note: image linked from the Egypt Museum] compare with the coin:
An excellent article here from Carole Raddato's "Following Hadrian" that explains:
"The vase represents a form of the Egyptian god Osiris depicted as a jar topped by a human head known as Osiris-Hydreios, or commonly Osiris-Canopus because it was originally exclusively connected to the Canopic region of Egypt."
And here is a description of the Canopic jar at the Egypt Museum which explains:
"Osiris-Canopus was named after the ancient Egyptian town of Canopus, on the western bank at the mouth of the westernmost branch of the Delta known as the Canopic or Heracleotic branch – not far from Alexandria."
Hadrian visited nearly every province of Rome including Egypt in AD 130 and where Antinous died and was deified as Osiris-Antinous. The Vatican Museum is the current home of the jar shown above, and also of a status of Osiris-Antinous the deified companion of Hadrian who died in Egypt, and a room found in Hadrian's villa called, "Antinoeion, a “special” place of worship consecrated to the young man, and possibly also including his tomb, that emerges along the final stretch of the paved road that leads to the so-called Great Vestibule of Hadrian’s Villa".
Egypt, Alexandria, Hadrian, AD 117-138, BI Tetradrachm, dated RY 10 (AD 125/6)
Obv: Laureate, draped, and cuirassed bust right
Rev: Canopus of Osiris (canopic jar) right; L ΔE-KATOV (date) around
Ref: RPC III 5578; Dattari (Savio) 1325-6