64 PLANTS, SEEDS, AND CURRENTS 



Islands. Had the bottle missed these islands, it would have been 

 borne north-east in the same current, and, getting within the influence 

 of the Brazilian Current, as it is deflected eastward, would have 

 entered the circulation of the South Atlantic. 



The Difficulties Connected with the Drifting Rates of 

 Bottles across the Atlantic — We come now to the discussion of 

 the time occupied by the drifting bottles in crossing the Atlantic, 

 either from the American or from the European and African side of 

 the ocean. In the charts the average drift per day is calculated up 

 to the date of the recovery of the bottle. This, as is pointed out by 

 the compiler of the American charts, must be in most cases less than 

 the actual drift-rate, since " no allowance is made for the time, 

 probably often considerable, during which the bottle lay undisturbed 

 on the beach." So also Schott observes (p. 10) that the calculated 

 velocities are merely minimum values, which could only in the rarest 

 cases correspond approximately to the true rate. This naturally 

 introduces an element of great uncertainty; but, if we assume that 

 20 or 25 per cent, of the bottles were recovered without great delay, 

 it is likely that we shall obtain an approach to the average drift-rate. 

 The results here employed have been calculated on this basis. As 

 before observed, the Prince of Monaco adopted a similar method in 

 estimating the mean velocity of his floats, usually taking the average 

 of the fastest fourth or third, except when the data were few, when 

 he selected the most rapid example. 



After handling the data during a long period it is not difficult to 

 recognise sets of results which possess a critical value. One of these 

 is given below in connection with five bottles dropped at the same 

 date into the sea in the vicinity of Cape Hatteras. Here it is not 

 hard to distinguish between the bottles that were quickly recovered 

 and those that had been lying a long time on the shore. It rarely 

 happens that we can exclude the element of uncertainty altogether. 

 But it is manifest, when the bottle is picked up afloat off a coast by 

 fishermen, or when the finder remarks that as it lay on the sand it 

 had all the appearance of having been washed up by the last tide, 

 that we are on relatively safe ground. Instances of both these 

 occurrences are mentioned in the following pages. As an example 

 of the great range of the periods elapsing between the start and the 

 recovery of the bottles I will cite the case of nine bottles which 

 crossed the Atlantic from the Florida region to the coasts of Europe. 

 Since the periods varied between eleven months and three years, it 

 is obvious that a year and more may be spent by a stranded bottle 

 before it is found. However, in the case of some of these belated 

 " finds " one may suspect that there has been a long sojourn in the 

 still waters of the Sargasso Sea, the notable gathering-place of the 

 wreckage of the North Atlantic. As in the instance of some bottles 

 cast up on the Azores, where an interval of several years elapsed, 

 one may seek here for an explanation of the great delay in the re- 

 covery. Such a case as is mentioned by Purdy in the Columbian 

 Navigator for 1839, where a bottle dropped overboard off Madeira in 

 June 1825 was picked up ten years after on the Turks Islands, may 

 be placed in this category. The table subjoined is intended to illus- 



