A naval mark II Bathythermograph, circa 1945.
Length: 77 cm.
Diameter: 16 cm.
Plate marked: 6655-99-923-8391 BATHYTHERMOGRAPH MK. 2. SER.R/75/HSJ145
MOD. RECORD plate.
Mounted on a later display stand.
Bathythermograph is an oceanographic instrument designed to continuously record temperature versus depth from a moving vessel. The origins of the instrument begin in 1935 when MIT Meteorology Professor Carl-Gustaf Rossby started experimenting with an early version of the instrument onboard the research vessel Atlantis. Rossby turned over development of the instrument to his graduate student Athelstan Spilhaus. By 1938, Spilhaus had developed a functioning instrument and coined the term “bathythermograph.” His invention immediately proved valuable for submarine warfare operations during WWII, and has provided a key tool for understanding the ocean’s temperature structure and its physics.