68 PLANTS, SEEDS, AND CURRENTS 



than a year, though the shortest period would be rather over ten 

 months. In Note 16 of the Appendix reference is made to a derelict 

 which drifted from Baltimore Bay to the Hebrides in a little over 

 ten months, but about half the time was spent drifting about within 

 a small area in mid-ocean. A critical value belongs to a rate of 

 eight miles which is given by Schott (p. 11, map ii.) for a bottle that, 

 after being thrown into the sea about 350 miles north-east of Cape 

 Race, was recovered on the Isle of Skye. According to the finder, it 

 appeared to have been thrown up at the last flood-tide. 



The uniformity in the average daily rate of eight to nine miles across 

 the North Atlantic is remarkable, and this brings us to record that 

 the average rates computed by the Prince of Monaco for his floats 

 in the eastern half of this ocean are only half this amount. His 

 observations, as we have seen, were made on a line drawn from the 

 Azores to the Banks of Newfoundland, as well as in localities to 

 the east and north of that line; and he places the average drifting 

 rate to the shores of Europe, ranging from Norway to Portugal, 

 at four to five miles a day. This discrepancy, however, is capable 

 of explanation, and I imagine that it may be largely discounted. 

 It is evident that the Prince of Monaco mainly based his rates on 

 the experiments made between June and July 1887, between New- 

 foundland and the Azores and to the north of that group. On the 

 other hand, the data tabulated above for this traverse are supplied 

 by records that cover a long period of years, and in this manner the 

 disturbing influences retarding the eastward flow of the surface- 

 currents during a particular year or season have been eliminated. 

 To such retarding influences experiments made in the same season 

 might be exposed. It is noteworthy that in the experiments of the 

 Prince of Monaco in 1886, when the floats were cast overboard at 

 distances ranging from 400 to 700 miles from the Portuguese and 

 French coasts, more rapid velocities were obtained. The five fastest 

 rates of eleven bottles stranded on the coasts of Portugal and West 

 Spain gave a mean of 7*15 miles a day. So, again, the mean of the 

 seven quickest rates for twenty-four bottles recovered on the west 

 coast of France was 6*67 miles a day. The Prince of Monaco's floats 

 were as a rule deeply submerged, and were thus much less likely to 

 be influenced directly by the wind than the ordinary floating bottle. 

 Yet the retarding effect of contrary winds might be counterbalanced 

 by the acceleration produced by fair winds. 



The Drifting Rates from off the Coasts of Europe to the 

 West Indies. — In making this traverse bottle-drift seems to travel 

 at about the same average speed as in the case of that brought to 

 Europe in the Gulf Stream — namely, eight to nine miles a day, the 

 time occupied being usually sixteen to seventeen months. But the 

 rate varies greatly in different portions of the traverse. It is in the 

 passage south from European latitudes to the region of the North 

 Equatorial Current that the slowest progress is made. From the 

 data supplied by a number of bottle-drifts in the American charts 

 it is evident that the average daily rate for this passage is only 

 four or five miles. On the other hand, as shown in the table, bottles 

 starting from the vicinity of the Canary Islands are carried into the 



