14 Papers from the Marine Biological Laboratory at Tortugas. 



The sounding-wire was 2.2 mm. in diameter and consisted of four 

 strands of eight wires each, made of high-tensile steel; the breaking strain 

 was given as 400 pounds, but in practice I have no hesitation in saying that 

 it far exceeded this figure. The wire was very difficult to kink, and did not 

 show any tendency to untwist or permanently stretch under a tension of 

 about 350 pounds; it proved in every way satisfactory. 



For measuring the length of wire run out, one of the fathom-measuring 

 sheaves made by the Telegraph Construction and Maintenance Company 

 of London was used. This consisted of a sheave containing a steel wheel 

 about 12 inches in diameter, grooved for and made especially to fit the wire; 

 the length of wire run out is measured by the number of turns of the wheel 

 indicated by a dial on the side of the sheave. The dial has two hands show- 

 ing fathoms and hundreds of fathoms; the hands revolve backwards on 

 winding in the wire, and so again register zero when the sounding is com- 

 pleted. The axle of the wheel revolves on simple bearings, avoiding thus the 

 slight inaccuracy if ball bearings are employed. 



Samples of the bottom were obtained with one of the "snapper rods" 

 disengaging an iron 30-pound weight on touching the bottom. This con- 

 sisted of two brass jaws closed by a strong spring, and kept apart by a 

 trigger; on touching the bottom the trigger was released and the jaws 

 closed on a sample of the bottom; at the same time the 30-pound weight, 

 which was only held in position through the tension of its own weight, was 

 disengaged as soon as the tension was relieved on touching the bottom, and 

 so was left behind as the wire was reeled in. 



In order to tell the depth at which bottom was sounded the wire was 

 led through a pulley connected with a spring balance, which accordingly 

 registered the tension of the wire. On touching the bottom the decrease in 

 tension due to the release of the weight was shown on the dial of the balance. 

 This arrangement was not satisfactory in rough weather, as the rolling of 

 the yacht caused such varying tensions on the wire that it was not always 

 possible to tell the exact depth at which the weight was disengaged. 



For obtaining samples of water for bacterial analysis a special water- 

 bottle was designed by Mr. D. J. Matthews. This apparatus is described 

 in detail by Mr. Matthews (12) in vol. ix, No. 4, of the Journal of the 

 Marine Biological Association of the United Kingdom, so only a brief 

 account of it will be given here. 



The apparatus employed by previous workers for obtaining samples of 

 water from the deep sea for bacteriological examination has either con- 

 sisted of some sort of water-bottle made of metal, or else of exhausted glass 

 bulbs with a neck drawn out into a capillary tube which could be broken 

 off at the depth from which a sample was desired. The use of exhausted 

 glass bulbs presents considerable difficulties for depths as great as 800 

 fathoms; the bulbs must be strong and very thoroughly annealed, as other- 

 wise the slight shock caused by breaking the capillary neck is liable under 

 the great pressure to make the bulb fly into small fragments; another 



