Hydrographical Observations from the Danmark Expedition. 295 



In the summer of 1906 both the water-bottles worked excel- 

 lently. After the mnter 1906 — 07 there were difficulties to begin 

 with, partly because the rubber of the valves had been frozen in the 

 winter, partly from the salt on the rods. 



The water-bottles were then washed in tepid freshwater and the 

 rods rubbed a little with oil ; the whole then worked excellently. 



To test the insulation of the water-bottles the following experi- 

 ments were undertaken in the summer of 1907. 



The water-bottles were filled with freshwater from a pool on land 

 and the temperature was read for some time, whilst the water-bottle 

 hung in the air, then it was let down to 5 m. in the cold water at 

 the place. It was hauled up to the surface at short intervals and 

 the temperature taken. 



"/б 1907. Water-bottle No. 39. Thermometer No. 23507. 



Air temperature + 4°. Temp, of the water — 1*75°. 



Air readings Difference 



3-^^ +3-57 



4-00 +3-64 -1-ou/ 



4-05 -f 3-74 + 0-10 



4-11 +3-87 + 0-13 



4-15 + 3-98 + 0-11 



4*20 water-bottle let down and s^vung regul- 

 arly backwards and forwards. 



Water readings Difference 



4-26 + 4-27 



4-31 + 4-37 + и iu 



4-36 + 4-32 - 0-05 



water-bottle hauled up into the air. 



4-41 -f4-17 -0-15 



4-46 + 3-88 - 0-29 



4-51 + 3-60 - 0-28 



4-56 + 3-37 - 0-23 



The difference between the air and water temperature was 5' 7°, 

 and cold water made its influence felt in the innermost cylinder of 

 the water-bottle after about 9 minutes. 



21/б 1907. Water-bottle No. 86. Thermometer No. 23507. Air 

 temperature -f IOC. Water temperature — 1-7. 



Air readings Difference 



2-25 + 9-63 



2.30 + 9-83 + III 



2-35-5 +10-12 I If 



2-40 + 10-36 + It; 



2-45 + 10-59 "^ 



Water-bottle let down and swung forлvards and backwards. 



