OCEANOGRAPHICAL RESULTS, MICHAEL SARS, 1900. 131 



Water-Bottles. For taking the temperature of the deeper 

 strata of the sea an insulated water-bottle of my construction 

 was much used (PI. 2, Fig. 1). This water-bottle (made by Mr. 

 Andersen of Christiania) was insulated by concentric water-jackets 

 upon the excellent principle introduced by Prof. Pettersson. There 

 were seven concentric water chambers with a diameter of 12'5 cm. 

 outside which there was a much larger concentric chamber, 

 filled with two layers of about 80 evacuated glass tubes, which 

 were coated inside with silver in order to prevent the emis- 

 sion of heat (PI. 2, Fig. 2). Between these two layers of glass 

 tubes was inserted a thin plate of ebonite^ to prevent circula- 

 tion In the lid and at the bottom, there were 7 plates of india 

 -rubber, placed horizontally at intervals so that 6 insulating water 

 layers were formed at each end. The arrangement for releasing 

 the lid when the bottle was set, was the same as that indicated 

 in my Memoir on 'The Oceanography of the North Polar Basin' ^. 



The cylinders when open, hung under the Hd. When 

 the lid was released and fell down on the cylinder in situ, two 

 excentric levers in the lid were released by a special arrange- 

 ment (PL 2, Fig. 3 and 4). As the lead was suspended under 

 these excentric levers (Fig. 4) they would, w^hen released, be tur- 

 ned down by the weight of the lead (Fig. 4), and the latter, with 

 a force 6 times multiplied, would now press the lid down against 

 the upper end of the cylinders, and the cylinders against the 

 bottom. Thus the water-bottle would be closed absolutely water- 

 tight, and not the shghtest trace of water could get out or in 

 during the hauling up. 



An essential point in the construction of this water-bottle 

 was the thermometei-. During my work with Petterson's insu- 

 lated water-bottle, I had experienced that it was a drawback to 

 have to insert a thermometer after the water-bottle arrived at 



^ The Norwegian North Polar Expedition 1893 — 1896, Scientific Results, 

 vol III, No. 9, p. 138. 



