I'ullcn. 



4 DEPTHS OF THE OCEAN 



During this expedition also some of the earhest attempts at 

 deep-sea sounding were made by Captain Phipps, the deepest 

 sounding being 683 fathoms, from which depth he brought up a 

 sample of Blue mud. 



In 1780 Saussure determined the temperature of the 

 Mediterranean at depths of 300 and 600 fathoms by protected 

 thermometers, and in 1782 Six's maximum and minimum 

 thermometer was invented, and subsequently made use of by 

 Krusenstern in 1803, by Kotzebue in 18 15, by Sir John Ross 

 accompanied by Sir Edward Sabine in 18 18, by Parry in 1819, 

 and by Dumont d'Urville 

 in 1826. Slow-conduct- 

 ing water - bottles were 

 used by Peron in 1800, 

 by Scoresby in 181 1, who 

 recorded warmer water 

 beneath the colder sur- 

 face layers in the Arctic 

 regions, and by Kotzebue 

 accompanied by Lenz in 

 1823. Protected thermo- 

 meters were used for 

 deep - sea temperatures 

 by Thouars in 1832, by 

 Martins and Bravais in 

 1839, and by Sir James 

 Clark Ross during his 

 Antarctic expedition from 

 1839 to 1843, the last- 

 mentioned making also 

 many observations on 

 the density of the water at various depths. In 1843 Aime- 

 introduced reversible outflow thermometers, and about 1851 

 Maury used cylinders of non-conducting material for taking 

 temperatures in deep water. But it was only when thermo- 

 meters with bulbs properly protected from pressure came into 

 use that oceanic temperatures could be recorded with precision. 

 The first thermometer of this kind seems to have been used in 

 1857 by Captain Pullen of H.M.S. "Cyclops," and shortly 

 thereafter improved forms of the Six pattern (Miller-Casella) 

 and of Negretti and Zambra's reversing pattern were introduced, 

 and have been largely used ever since, improvements and 

 modifications being incorporated from time to time. 



Captain James Cook. 



