— XLIII — REPORT 1902-03 APPEND. A 



A few of these thermometers have been distributed by the G. L. to different 

 expeditions of the participating states. The model is however still not finally 

 settled. 



The reversing thermometers sent out by the G. L. are tested there by a 

 determination of two points — the zero and one other point — and by calibra- 

 tion with a mercury thread of 4 or 5 degrees length. 



A water-bottle specially adapted for use with the reversing thermometers, 

 has been invented. The cylindrical bottle which carries the thermometer case is 

 reversed by its own weight ; and by an excentric mechanism the India rubber ends 

 are pressed tight against the two extremities of the cylinder. The bottle has been 

 found to work quite well. With a capacity of rather more than 500 cm^ it 

 weighs 4 or 5 kg and costs 100 or 120 Kr. It can be obtained adapted for 

 either propeller or messenger. 



VI. Gurrent meters. 



Several experiments have been made to find out a sensitive and reliable 

 current-meter. After some trials which were less successful, two instruments have 

 been constructed which it is expected will prove suitable for work on the regular 

 cruises. One of them is a pendulum apparatus according to a principle already 

 described*). The inclination of the pendulum is repeatedly recorded on a compass 

 disc covered with paraffin wax. This apparatus when hung on a tripod which is 

 then lowered to the bottom of the sea records very satisfactorily the slow move- 

 ments just above the sea-bottom. In this way the apparatus is made quite in- 

 dependent of swaying of the line etc., and it has been proved capable of recording 

 oscillations as well as steady currents, down to speeds of 1 cm per second, quite 

 reliably. 



The second kind of current-meter constructed by the G. L. gives the velo- 

 city by means of a propeller. The direction of the current is recorded repeatedly 

 by small shot dropping on to the centre of a magnetic needle thence along its 

 north end and so to the bottom of the compass box, which is divided into com- 

 partments corresponding to the points of the compass. It records the velocity and 

 direction of currents of 4 or 5 cm velocity and more. By kind permission of Dr. 

 JoHAN Hjort, the director and first assistant were enabled to test the instruments 

 which worked very satisfactorily, on board the "Michael Sars". A detailed de- 

 scription of these instruments will be published subsequently. As it seemed im- 

 probable that reliable measurements of weak currents could be made with an in- 

 strument suspended from an anchored ship, an arrangement was invented and 



*) V. Walprid Ekman: On a new current-meler invented by Prof. Fridtjof Nansen. Nyt Maga- 

 zin for naturvidenskab. XXXIX. Kristiania 1901. 



