1018 DR. G. HERBERT FOWLER ON THE [Dec. 13, 



the condition of the paint and the small quantity of bottom-deposit 

 in the collecting- tin, that the net had not more than touched 

 bottom without dragging on it, I was able to get, from this 

 accident, data for the correction of the other deep-water hauls. 

 "While, therefore, the horizons of the Mesoplankton hauls may 

 perhaps be understated (if the net had rested long on the bottom 

 in haul 16 a i), the depth is certainly not exaggerated. 



That the calculation of the depth reached in this manner was 

 a very close approximation to the truth, can fortunately be shown 

 in another way. During the 1896 cruise, Captain Moore and the 

 other Officers were engaged in taking serial temperatures 1 ; and a 

 minimum thermometer was sent down on the locking-gear of my 

 net with every haul after 12 e. A comparison of the temperatures 

 thus recorded on the net, arid of the temperatures independently 

 observed or interpolated on a curve by the Officers, is given 

 below, where column I. shows the station number and haul letter ; 

 column II., the probable depth reached by the net (about 50 

 fathoms below the point at which it opened) as calculated from the 

 data furnished by Station 10 ai when the net struck bottom; column 

 III., the temperature recorded by the thermometer on the. net, after 

 correction ; column IV., the temperatures for the depth given in 

 column II., as independently observed or interpolated in the curves 

 in Captain Moore's Report. 



I. II. III. IV. 



13 a 180 47-0 47'0 



136 356 32-6 33-0 



13 d 445 32-0 31-25 



13 e 445 32-0 31-25 



13 </ 516 3075 31-0 



15 c 578 31-0 30-75 



16 a i 400 30-6 30-9 at 380 fath. 

 16 a ii 356 31-0 31-5 



18 1 578 31-0 31-0 at 600 fath. 



19 a 534 46-0 46-8 at 550 fath. 



Considering the different times of day, and the slightly different 

 positions owing to the ship's drift, at which the two sets of observa- 

 tions were made, their approximation is very close. 



With the net of the 1897 pattern, which presented less resistant 

 surface and less buoyancy than the other, no calculation of the 

 depth was required : the line hanging vertically to the surface, the 

 number of fathoms paid out indicated the depth sufficiently 

 accurately. As to the rate of travel of the messengers, had time 

 (i.e. weather) permitted, this would have been carefully worked into 

 a curve : as it Was, the impact could be felt at the less depths, and 

 had to be guessed (good margin being allowed) for the greater 

 depths. That the messengers travelled very rapidly was shown 

 by the deep dints that they received on striking the locking-gear. 



1 W. U. Moore : Eeports of Proceedings in connection with Investigations 

 into the Physical Conditions of the Water of the Faeroe Channel. Hydro- 

 graphic Department, Admiralty, 1896, 4to. 



