On the specific gravity, and temperature of Sea Waters, in different parts of the Ocean, and in particular seas" with some account of their saline contents. Read May 20, 1819.

(London, W. Bulmer and Co., 1819). 4to. No wrappers as issued in "Philosophical Transactions of the Royal Society of London for the Year MDCCCXIX", pp. 161-208 and 2 engraved plates, showing his invention of the samplin bottle aimd at getting samples from the depth of the oceans. First printing. Marcet undertook some of the first measurements of the concentration of different salts in sea water. He was an early marine chemist and a allround scientist and performed some of the first measures of the concentrations of the major salts in sea water. He found that all sea water contains the same salts in nearly the same concentrations. He invented the "Sampling Bottle".