THE NORTH AFRICAN CURRENT. 313 



in 1853. As the charts contained in that work* embrace a much wider 

 range of observation than was before attainable, we shall quote on this 

 Current, as on the other branches of the subject, the general remarks based 

 on the results obtained for each month. 



(264.) By a careful calculation of the Currents experienced by the ships 

 cited in Maury's and Rennell's Charts, they appear to set with great regu- 

 larity, and constantly to the South-Eastward. The experience of eighty- 

 two ships for the year gives a mean direction and rate of 9*1 miles per day 

 to E. 34° S., for the offing of 350 miles off Cape Finisterre and the Northern 

 part of Portugal. The average of the months is greater than this : — 

 January, 9-4 miles to S. 40° E. ; February, March, April, 11, 15-9, and 

 12-8 miles per day to E. 24° S. ; May, July, 12-8 and 10 miles per day to 

 S. 25° E.; August, October, November, 20*2, 10-5, and 16-7 miles per day 

 to S.S.E. These, compared with the drift of Bottles, show that the latter 

 must be affected by surface causes, as their rate of travelling is much less.f 

 All these observations are integrated on the Chart of the North Atlantic 

 Ocean, referred to previously. 



(265.) We now give the remarks drawn up by Mr. Strachan on this 

 Current in the work before quoted, first those for the annual mean, and 

 then for each month in succession. 



The North African Current. — If a line be traced from the Azores to 

 Madeira, and thence to the African coast, in lat. 28"^ N. (Canary Islands), 

 it will be seen that to the Northward, as far as lat. 40° N., the average 

 general direction of the Current is to the S.E., at from 3 to 12 miles a day, 

 the rate being strongest between long. 10° and 15° W. Eastward of the 

 10th meridian the direction becomes more Easterly toward the Straits of 

 Gibraltar, but counter-currents have been experienced off the coasts of 

 Spain and Morocco. It is to be noticed that the resultant rate close to the 

 coast of Portugal is only 1*4 mile a day, arising from the variation in 

 direction of the observations here. South of Madeira the Current, between 

 the coast and the 20th meridian, turns to the South, and then to S.S.W., 

 down to lat. 10° N., its rates ranging from 3 to 13 miles per day. Between 

 the meridians of 10° and 20° W., and the parallels of 30° and 10° N., this 

 Current appears to slough oft' to the S.S.W., S.W., W.S.W., and finally 

 merges with the Westerly drift of the North Equatorial Current about the 

 meridian of 20° W., the rate being about 6 to 9 miles a day. 



On the whole it does not appear that the waters of the North African 

 Current mingle to a great extent with those of the Guinea Current. On 

 the contrary, it would seem that they are finally forced towards the West 

 by the superior strength of the Guinea Current. Even the portion of the 

 Current which passes Eastward of the Cape Verde Islands does not appear 



* Currents and Surface Temperature of the North Atlantic Ocean, from the Equator 

 to lat. 40° N., for each month of the year. 



t Estimating the set of the Current by Captain Becher's Bottle Chart, mentioned 

 on page 295, we get the following : — Bottle No. 7 (drift 500 miles), 3-2 miles per day; 

 No. 8, the carcase of a dead whale (220 miles), 8 miles ; No, 9 (300 miles), 12 miles ; 

 No. 13 (250 miles), 4-1 miles; No. 18 (1,000 miles), 3 miles; No. 136 (550 miles), 

 5-5 miles per day, giving an average of nearly 6 miles per day. 



N. A. 0. 41 



