264 



JAKOB SCHETELIG. 





Depth 



I 



II 





Station 



in 



17-5° 0. 

 « 17-5° C. 



17-5° c. 

 '^ 17-5° C. 



Difference 





Metres 





9 



600 



102662 



1-02663 



0-00001 



10 



20 



2690 



2691 



1 



18 



1300 



2665 



2666 



1 



n 



1500 



2664 



2666 



2 



■ 29 



800 



2665 



2666 



1 



„ 



1000 



2664 



2666 



2 



n 



1500 



2666 



2666 







34 



500 



2667 



2668 



1 



The mean difference here is O'OOOOU. If thé necessary 

 correction for evaporation be apphed, it may safely be asserted 

 that the Hmit of error in the determinations Hes below + 0"000005. 



There would be no great difficulty, I believe, in attaining 

 to still greater accuracy by this method. 



With a hydrometer of total immersion with a volume of 

 about 120 c. cm. and a specific gravity at 175° C. of I'OOOO, in 

 which an additional weight of 1 mgr. answers to an increase of 

 O'OOOOl in the specific gravity — , further, with the weight 

 always determined with an accuracy of 1 mgr., the bath arranged 

 with constant temperature, and the sample kept covered as much 

 as possible during operations, it would be possible to determine 

 the specific gravity of sea- water at ^° C. (the constant temper- 

 ature) with an accuracy which my experience would lead me to 

 put at ± 0-000002. 



Kristiania, June, 1901. 



Jakob Schetelig. 



Trykt 27 juni 1901, 



