Published online by Cambridge University Press: 05 December 2011
A historical review of the physical and chemical data collected from the Suez Canal waters in the first 40 years (1867–1906) during and after its filling shows that it was the focus of interest of many explorers and scientists. From 27 successive observations (table) the waters were completely analysed seven times. The salinity (density) was measured along the canal on eight occasions, of which four were not previously known. The first observations along the Canal were made in May 1870 by the Admiralty Ship Blue Cross. Her results, together with the second set of observations (February 1872), were found in a small booklet printed in Alexandria (Tissot 1872). The data of two sections (Durand-Claye 1875a; Anonymous 1907) were found by the author as unpublished manuscripts and are revealed here for the first time.
A comment on the determination of salinity of sea water by evaporation to dryness was found in a handwritten manuscript by Durand-Claye (1873). This comment was eliminated in the published text (Durand-Claye 1874), and is reproduced here for its interest to the history of chemical oceanography.
The difficulties in making a comparative study of these old data are explored. It is suggested to start some sort of ‘practical historical oceanography’ by studying old hydrometers, thermometers and other oceanographic apparatus using modern equipments in order to reassess the data of old expeditions.