Copy letter from Edward Sabine, Foreign Secretary of the Royal Society; to Sir F [Francis] Beaufort Explains that Dr Forchammer is an eminent Danish philosopher based in Copenhagen [Denmark]. This work is in the levels of lime in sea water, which has widened to investigate how this level diminishes from the equator to the poles. Informs of a letter from Dr Forchammer asking for samples from the Mediterranean sea. The samples should be taken from six or eight different locations; from the surface; 100 fanthoms down; and as deep as can be conveniently possibly. The samples are to be labelled. 7 January 1850