The discourse was completed at the latest by 1675 but not printed until 1703. Presumably this manuscript is one of those distributed by Shere to his friends (Pepys being one) and possible patrons. There are frequent variations between this manuscript and the printed version.

In 1675, Shere's observations were welcomed by the Royal Society as the solution to a problem which had baffled thinkers from the earliest times: why the level of the Mediterranean never rises in spite of currents from the Atlantic and the Black Sea, 150 disgorging rivers, not to mention rainfall. His theory, which turned out to be wrong, was the equilibrium of the Mediterranean was maintained by evaporation. However, his efforts to determine the rate of evaporation were original and valuable.

There is included a page of diagrams provided at the end of the discourse.

Administrative / biographical background
Henry Shere was an engineer who had worked on the Mole during the British occupation of Tangier and superintended its destruction in 1683. He was knighted in 1685 and made surveyor of the Ordnance about the same time. He was also a member of the Royal Society and his printed works include translations of Polybius and some dialogues of Lucian.