Page:The National geographic magazine, volume 1.djvu/195

 covered along the east coast of Florida, while of those thrown out east of the axis not a single one was heard from. As a rule it was found that the stronger the current the more constant the direction and the deeper the stratum. Remarkable fluctuations in the flow near the axis were noted, the velocity increasing sometimes one knot in ten or fifteen minutes, and then as suddenly decreasing again. Lieutenant Pillsbury attributes this, however, to a serpentine movement of the maximum flow, which would sometimes strike the station occupied by the Blake. The edge of the stream was found at about 30 miles south of Rebecca Shoal light-house.

Between Yucatan and Cape San Antonio the stream was found flowing about north, and the line of maximum velocity corresponds on the average to 10h before and to 2h 20m after the moon's transit. The excessive variations were like those in Florida Strait, on the west side of the stream, and the maximum velocity of 6¼ knots was found about 5 miles off the 100-fathom line of Yucatan Bank. The eastern edge of the stream lies about 20 miles west of Cape San Antonio, and between this edge and the island, eddy currents exist. At the time the easternmost station in this section was first occupied, the declination of the moon was low and the set of the surface current north-easterly. At a high south declination of the moon the surface current was found south-easterly in direction, and east or south-east below the surface. The normal flow below the surface was in each case from the Gulf into the Caribbean Sea, and this makes it probable that the station was situated inshore of the average limit of the stream. On Cape San Antonio Bank the currents are tidal, flood running northward and ebb southward. On the Yucatan Bank the currents were also tidal, but as the edge of the bank is approached the stronger flow of the Gulf Stream predominates. The monthly variation in velocity, which was found clearly defined at the first two sections occupied, appeared at this section to be obliterated by anomalies not existing at the former.

Off Cape Hatteras the Blake accomplished the remarkable feat of remaining at anchor in 1,852 fathoms, and this with a surface current of over 4 knots. Two stations were occupied, and similar variations in velocity were observed as at the other stations. The notable feature at this station was the discovery of tidal action beneath the Gulf Stream, the currents at 200 fathoms depth changing their direction very regularly, the average current flow-