Intelligence and Miscellaneous Articles. 405 



ON THE TEMPERATURE OF SEA-WATER. 

 BY M. CHARLES MARTTNS*. 



I have read with great interest M. Edlund's Note on the Forma- 

 tion of Ice in the Sea, published in the Archives des Sciences Natu- 

 relles of July 20. His observations render it difficult not to admit 

 that ground-ice may be formed in salt water as well as in fresh. 

 The fact that, in nature, the temperature of sea-water descends 

 below zero without ice being formed can no longer be contested. 

 In the two voyages made in 1838 and 1839 by the corvette ' La 

 Recherche ' to Spitzbergen, I determined the temperatures at the 

 bottom of the sea in the neighbourhood of the glaciers, which, in 

 that region, often descend to the sea, and even advance, overhang- 

 ing the surface of the water, to some distance from the coast. In 

 these experiments, published fifteen years ago in the Voyages de la 

 corvette ' la Recherche,' vol. ii. p. 279, and in the Annates de Chimie 

 et de Physique, 3 e ser. vol. xxv. p. 172, I used, for temperatures 

 above zero, Walferdin's overflow-thermometers with arbitrary scales. 

 For temperatures below zero, I employed thermometrographs with 

 indexes unprotected from pressure ; but I took care to correct their 

 indications by means of coefficients obtained from comparative ex- 

 periments made with overJiow-instruments, protected from pressure 

 by tubes of crystal : besides this, I always took the precaution (in- 

 dispensable in experiments of this kind) to employ several thermo- 

 metrographs at the same time, in order that their indications might 

 rectify each other. 



Most of the experiments were made in August 1839, opposite the 

 great glacier at the bottom of Magdalena Bay, on the east coast of 

 Spitzbergen, in latitude 79° 34', and longitude 8° 49' east of Paris. 

 The temperature of the surface was always a little above zero ; it 

 varied, in fact, from 0°'l to 1°'2. Nevertheless twice a day, at low 

 water, enormous masses of ice fell down into and cooled the sea. 

 The temperature of the air at the surface of the sea varied from 0°'7 

 to 6°'0. From the surface of the water down to a depth of 70 metres 

 I never found the temperature to be below zero ; but beyond this 

 depth, and down to the bottom of the sea, the temperature was 

 always below zero, its mean value being about — 1°-75. The lowest 

 temperature was found at a depth of 110 metres, and at a distance 

 of 1350 metres from the glacier at the bottom ; it was — 1°*91. The 

 most elevated of these low temperatures was found at the less con- 

 siderable depth of 73 metres, and amounted to — l° - 29. It would 

 be wrong, however, to conclude that the temperature sinks regularly 

 as the depth increases, for at 136 metres I only found it depressed 

 to -l°-78. 



In the open sea I never observed a temperature lower than zero 

 at any depth whatever. For instance, on the 20th of July 1839, in 

 73° 36' north latitude, and longitude 18° 32' east of Paris, I lowered, 

 to a depth of 870 metres, four of Walferdin's thermometers protected 

 from pressure by tubes of crystal soldered by the blowpipe. Their 

 indications agreed wonderfully well with each other, and showed a 



* From a letter to M. E. Plantamour, published in the Bibliotkeque 

 Universelle, Archives des Sciences Phys. et Nat. vol. xxi. p. 'AJ (1864). 



