A large vessel supported by twelve oxen is called “brazen sea”, “molten sea”, “cast metal sea”, or “copper sea”. It is mentioned in a few places in the Bible. It is a washing basin for priests. The image can be found on Ancient and Accepted Scottish Rite drawing for several degrees.
In the Mirecourt collection of degrees, the image is explained in the 13th degree called “Chevalier d’Orient” (‘Knight of the East’). First it is said that the Copper Sea was taken out of the rubble of the Temple by Nebuzaradan under order of Nebucadnezar. In the Baylot collection there is a text explaining so-called Scottish emblems”. Here the 12 oxen represent the 12 apostles who carried the Holy Water around the world.
Here we have an old one from 1765 France (Mutus Liber Latomorum).
In Les Plus Secret Mysteres (1820) the Brazen Sea is displayed from above.
The image is also displayed on contemporary French 15th degree AASR tracing boards.
First and second: Dąbrowski P. 212 (“Symbols of the Ancient and Accepted Scottish Rite”). Year and designer unknown.
Bottom: Mutus Liber Latomorum (1765)