Auu John B. Tait 



transport value of all in Table I, namely that of 1-4 km^/hr for the third week of 

 August 1927, and of the quite unique occurrence, so far as is known, of an iceberg 

 within the limits of the North Sea, sighted on 23rd October 1927 about 30 miles ESE 

 of the Outer Skerries of east Shetland (Marine Observer, 1928). 



Oppositely, it may here also be pointed out that the highest transport value in 

 Table I of almost 20 km^hr occurred during a summer which was outstanding 

 meteorologically over the greater part of the continent of Europe. 



Further as regards the higher transports, however, it is to be noted that not all of 

 these are recorded against the spring-summer months of May, June, and July, as 

 witness, for instance, the figures for September and November 1949, and also that for 

 November 1952. This feature of the results is considerably enhanced and extended 

 when further available material is added to that of Table I. Besides the paired 

 hydrographic sections there represented, no fewer than twenty-four single sections, 

 a number of them traversed by the Danish research vessel Dana, and one due to the 

 Norwegian vessel Armauer Hansen, embracing the same period of years, are available 

 for dynamic computation on the same lines as those adopted for the Scottish sections. 

 Single section computational results must, of course, lacking similar corroboration 

 to those of the paired sections, be regarded as probably somewhat less rehable on 

 that account. None the less, they are of no small value in extension of Table I, and 

 have accordingly been incorporated along with the means of the paired values, in 

 Table II, single section values being distinguished by an asterisk. 



In this table, the high figure of 13-3 km^hr for the month of June 1929 as derived 

 by Helland-Hansen (1934) clearly supports the mean value of 13-6 km^hr in respect 

 of the previous month; and the introduction of an additional year, namely 1934, on 

 the basis of single sections only, but in no fewer than three separate assessments, in 

 no way impairs the inference already tentatively made as regards the apparent suc- 

 cession of low summer oceanic transports between 1931 and 1936 inclusive. Like- 

 wise, the slightly high figure of 9-3 km^hr for May 1938 probably anticipates in truth 

 the subsequent increase to 11-2 km^hr some six weeks later, and the assessments for 

 June and July 1939 would appear to be very similarly related. 



It is only from the year 1949 onwards that autumn- winter transports are available, 

 and these, to 1952 inclusive, reveal conditions which, although hitherto perhaps 

 occasionally suspected on empirical circumstantial evidence, are here for the first 

 time given quantitative expression. In each of the four years concerned, the oceanic 

 volume transports through the Faroe-Shetland Channel were evidently of greater 

 intensity than the preceding spring-summer incursions. It is material also that the 

 years are consecutive, for, from the standpoint of long-term variations, it would 

 almost appear from the values given that the successive autumnal accessions to the 

 intensity of the oceanic influence in the Channel themselves increased annually to a 

 high maximum in December 1951. It can be taken as practically certain that the 

 phenomenon of greater autumn-winter than spring-summer oceanic transports is not 

 an annual occurrence, the combination of circumstantial with the factual evidence 

 of Table II and such assessments as are available for earher years (Helland-Hansen, 

 1905, and Robertson, 1905, 1907, 1909a, 1909b, 1913), suggesting that this oceano- 

 graphic feature, hke that of the succession of low summer transports between 1931 

 and 1936 inclusive, occurs in groups of years, and recurs only at more or less long- 

 term intervals of the order each of at least several years. Qualitative evidence in 



