I9I5- No. 2. SPITSBERGEN WATERS. 



mometer. On the afternoons of August 13th the second thermometer again 

 registered correctly, and after that time it showed no such appreciable 

 irregularities except on August 26th (Stat. 46, 100 metres» and 31st tStat. 

 52. 20 metresi when it gave — 1.09 *'C. and 0.20'' C instead of — 0.40" C. 

 and 0.36 "^ C. If only the one thermometer had been used on these occa- 

 sions there would hardly have been any reason to doubt the trustworthv- 

 ness of the readings, and the result would have been quite erroneous values 

 of temperature. It proves the great desirability of always using two ther- 

 mometers at each depth. 



Another peculiarity with this thermometer, No. P.T. R. 375 47, is that 

 it now and then seems to alter its correction about 0.03 '*C. In most cases 

 there was either no difference or a difference of about o.oi'^C. between 

 the temperature- values of this instrument and those of the first thermometer 

 of the same water-bottle, while frequently the former were about 0.03*' C. 

 higher than the latter. The cause of this variation is probably slight va- 

 riations in the manner in which the mercury thread is broken off. 



The observations taken with the two stop-cock water-bottles I 

 and II show an almost permanent difference of o.oi '^ C. between the tem- 

 perature-values obtained by the first and the second thermometer of each 

 bottle. This must be due to slight changes in the errors of freezing-point 

 of at least two of these thermometers which, however, were all of them 

 very trustworthy instrument as is also proved by the agreement between 

 their readings. 



The Salinities. All water-samples were preserved in glass-bottles 

 with porcelain stoppers, fitted with rubber washers and lever fastenings. 

 The bottles would hold about 200 c.cm. The salinities of the water-samples 

 have been determined with the interferometer, constructed by Dr. Löwe 

 (Carl Zeiss. Jenai. The double chambers of the interferometer used for 

 these investigations had been especially constructed for me by Zeiss, and 

 were made of glass. They had lengths of i and 2 cm., and gave very 

 satisfactory results. The readings of the interferometer were checked by 

 the ordinary standard water supplied by the Bureau of the International 

 Council at Copenhagen, and also by some other sets of water-samples with 

 various salinities, which had been carefully determined by several series of 

 titrations (Mohr's method I, carried out by Professor Helland-H.ansen and 

 his assistant, Mr. Torbjörx Gaarder. I wish to express here my sincere 

 gratitude for their valuable assistance. The determinations with the inter- 

 ferometer were made with great care and accuracy by my assistant, Cand. 

 Real. Jacob Helland, in the winter of 1912 — 1913. Now and then some 

 determinations were also made bv mvself as a control, but we nearlv al- 



