68 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. [66] 



general easterly coimter-set, of which adv^tiutage is frequently taken by 

 the coasters in working to windward. . 



In the western part of the Caribbean Sea the strength of the westerly 

 set is mucli less than farther east. Off the coast of the Isthmus of 

 Panama there is not infrequently a counter-current to the eastward, 

 which, although slight, is doubly perplexing from the fact that allow- 

 ance is generally made for the usual westerly set. This may sometimes 

 be accounted for by a continuance of northerly or northwesterly winds, 

 but has at times been known to exist without that apparent cause. 



In the bioad channel between Yucatan and Honduras in the west 

 and Cuba and Jamaica in the east the currents are extremely erratic. 

 The amount of northwest drift in twenty-four hours was found generally 

 to tail}' with what vessels have usually experienced there, being about 

 30 to 40 miles in a day; but during individual hours or portions of a 

 day there were remarkable fluctuations noted. For instance, the cur- 

 rent was WSW. 2^ knots an hour at one time; in two hours after- 

 wards, just a few miles to the northward, it was setting feebly east- 

 ward; and again in two hours more, to southwest, and later on to the 

 northwestward. This may be due to tidal influences, but it seems proba- 

 ble that the movement of the water is largely affected by tiie extra- 

 ordinary variations in the depth, nearly 3,200 fathoms being found 75 

 miles eastward of Swan islet (60 feet high), 3,000 fathoms at 40 miles 

 southeast of Misterioso Bank (10 fathoms), and so forth. 



Fortunately while in this vicinity circumstances were very favorable 

 for locating accurately each individual sounding, a bright moon lighting 

 the horizon at night so that altitudes of stars could be observed at each 

 station. 



During the summer and autumn of 1884 hydrographic work was 

 merely incidental, as continuous dredging and trawling generally inter- 

 fered with the correct locating of the stations. Still, a number of the 

 soundings taken were considered plotted with sufiicient accuracy to be 

 of hydrograi)hic value. This work was off the United States coast be- 

 tween Cape Hatteras and George's Banks. 



Nothing of sx)ecial interest was definitely ascertained. But in the 

 course of the season it became very evident that in the vicinity of the 

 40th i)arallel and the 70th and 7 1st meridians there is an easterly and 

 a westerly movement of the water, alternating at intervals of apparently 

 about half a day. Circumstances prevented a close examination into 

 this matter, but, as the approximate time of the change of the current 

 was noticed on several occasions to be later each day, it is believed that 

 the phenomenon may be attributed to the influence of the moon, and 

 that probably there may be tidal currents, less pronounced, but as regu- 

 lar there as along shoTb. 



Indications were also found of a pocket running in northward from 

 the GOO-fathom line on about the meridian of 70° 15', differing from the 

 contour lines on existing charts. But, owing to cloudy weather and the 



