Specific gravity (density) measurements taken from the HMS Challenger and SMS Gazelle in the global ocean from 1873-02-15 to 1876-06-05 (NCEI Accession 0228229)

Data were digitized by W. John Gould and Stuart A. Cunningham from cruise reports. The 1870s specific gravity (SG) measurements were used to calculate equivalent salinities under the assumption that the SG measurements corresponded directly to density, using the reference value for water of 1.0 gram/cm3. The temperatures to which the 1870s data were standardized: 15.56°C for the Challenger data and 14°Réaumur (17.5°C) for Gazelle. Data are in the comma separated value (csv) files, one for each cruise.