364 PETTERSSON , SIBERIAN SEA. 



water. Unhappily there exists, as may be seen from the table, 

 no deepsounding from this place. ^ 



From Cape Irkaipij [on the 12'^'' Sept.] to the arrival at 

 Pitlekaj [on the 28*'' Sept.] the temperature of the sea was 

 found to be at its freezmg point and the progress of the 

 expedition was accompanied with a continual struggie against 

 the ice. The deep-soundings from this part of the voyage are 

 represented on diagram X. 



The depths of the sea are not expressly mentioned in the 

 tables 1 — 4, because the necessary information can be got most 

 easily from the hydrographic maps. The nature of the sea- 

 bottom - is registered in Dr. Stuxberg's paper: »Evertebrat- 

 faunan i Sibiriens ishaf;>, Vega-expeditionens vetenskaphga 

 iakttagelser, I. Some minor discrepancies between the anno- 

 tations in the meteorologic and the hydrographic journal 

 regarding the localities, from which the samples were taken, 

 the spec. gravity of the sea-water at the surface, the depths 

 and the occurrence of ice etc. . . I have tried to remove by 

 comparison with the log-book of the ship, the reports of Prof. 

 Nordenskiöld, the Italian description of the Vega-voyage 

 by Mr. Bo ve etc. . . 



* Vegas färd kring Asieu och Europa, page 405 (Swedish edition). 



■^ Regarding the coloiir of the water of the Siberian Sea I wish to call 

 attention to an important investigation entitled: ^La couleur des eaux», 

 recently published by Professor W. Spring, from which I borrow the fol- 

 lowing lines, which will be found to have a direct application on the obser- 

 vations of the Vega-expedition (see the maps, plate 24 & 25). 



sOn sait que Targile ou le silicate d'aluminium, sans éti'e soluble dans 

 l'eau, dans Tacception propre du mot, forme cependant avec elle une pseudo- 

 solution: de Teau d'un tieuve, roulant sur un limon gi"as, argileux, ne devient 

 jamais complétement limpide par le repos. L'argile, sans étre dissoute, est 

 comme emulsionnée dans le liquide. Mais si Ton vient ä ajouter ä Tean 

 une solution d'un sel, du chlorure de sodium, par exemple, alors le silicate 

 d'aluminiuni se précipitera rapidement. On observe ce fait, sur une échelle 



enorme ä Tembouchure des grands fleuves Le sel häte la précipitation 



du silicate d'aluminium, dont la présence dans Teau, sous la forme de 

 precipité naissant, contribue au développement de la couleur verte des eaux.^ 



