OCEANOGRAPHICAL RESULTS, MICHAEL SAKS, 1900. 135 



rod, this water bottle can easily be attached to the souding- 

 line at any intermediate depth. The instrument worked satis- 

 factorily, and gave of course very trustworthy water-samples. 

 One draw-back, however, was, that the tubes were not tinned or 

 nickel-plated inside; the brass was therefore coroded by the 

 sea-water, and some of the water-samples were more or less 

 contaminated by copper salts. 



A similar water-bottle was also constructed, which had only 

 one tube with stop-cocks while the tube on the opposite side 

 of the central rod was replaced by a reversing apparatus for 

 Negretti and Zambra's thermometers. The tube of this water- 

 bottle was widest at the centre, and tapered off towards the 

 stop-cocks at both ends; the diameter of the aperture of the 

 latter was thus smaller than that of the central portion of the 

 tube. The tube inclosed more than half a litre of water 

 without any excessive length, the water was made to flow with 

 sufficient rapidity through the tube during the passage down; 

 by the conical mouth-piece at the lower end. I 



The determinations of the deep-sea temperatures were 

 chiefly made by the insulated water-bottles, described above, an4 

 the fixed deep-sea thermometers. These iustruments were made 

 of Jena Glass No. 59 HI, and had been very carefully tested at 

 the German 'Reichsanstalt' at Charlottenburg. Their zero points 

 were also tested several times during the voyage, with ice carried 

 for the purpose from Norway, and also with snow from the moun- 

 tains at Dyrafjord in Iceland. Their zero points underwent only 

 very slight changes. The thermometers were always read to 

 001° C. by a specially constructed lens or microscope, which 

 was placed perpendicular to the thermometer-scale and thus ex- 

 cluded the possibility of an error of parallax. 



All thermometers were also occasionally compared with a 

 standard thermometer of 'verre dur' from M. Baudin in Paris. 

 M. Guillaume of the 'Bureau International de Poids et Mesures' 

 had done me the great favour of examining this instrument very 



