The Hydrography of the Faeroe- Shetland Channel 77 



chlorine titrations were carried out for me by Mr. J. J. Manley, 

 Magdalen College Laboratory, Oxford, and my best thanks are due to 

 him for his assistance. The salinities were originally obtained from 

 the chlorines by the use of the table which I published in the ' Report 

 of the Fishery Board for Scotland ' (No. 12, 1S93, p. 381). They have 

 since been compared with Knudsen's authoritative tables, issued 

 recently ; the differences were insignificant. 1 I am indebted to my 

 friend, Mr. 0. J. R. Howarth, for assistance in reducing, tabulating, 

 and plotting the results. 



In arranging the material for discussion and comparison with other 

 observations, the first point to be noted was that the most important 

 series (and the only ones dealt with here) consist of nearly parallel 

 double lines of soundings, one line starting from near the north end of 

 the Shetlands, and another from near the south end, and both extending 

 to the Faeroes. An examination of all the Walwins observations, of 

 the observations made by the Jackal in the cruise of 1893, and again by 

 the Jackal in 1902 (see Helland- Hansen in Nature, vol. lxvi., p. 654), 

 indicated that these lines were so close together that they could for 

 all practical purposes be regarded as one and the same. Two points, 

 in positions (approximately) Lat. 59° 56' N., Long. 1° 24' W., and 

 Lat. 61° 45' N., Long. 6° 48' W., were accordingly selected, and joined 

 on the chart by a straight line to which perpendiculars were drawn 



1 In his paper on hydrographical investigations in the Faeroe-Shetland Channel, 

 etc., in the year 1902 (Report Cd. 2612, 1905), Helland- Hansen says: 'Dickson's 

 calculations of the salinities are partially based upon Pettersson's tables. I have 

 found that these give the salinities higher by almost 008 per cent, than Knudsen's 

 tables. 1 I am unable to understand this, a comparison of my table with Knudsen's 

 giving the following results : 



Salinity. 



CI. 



Knudsen. 



Dickson. 



Difference. 



17-5 



31-62 



31-65 



+ 0-03 



ISO 



32-52 



32-54 



+ 002 



18-5 



33-42 



33-44 



+ 0-02 



19-0 



34-33 



34-33 



000 



19-5 



35-23 



3523 



000 



200 



3613 



36-12 



-o-oi 



20-5 



37-03 



37-01 



-0 02 



H. 



N. D. 



