stream may have been the cause of some 

 of the bergs in the Atlantic this year, but 

 when it is remembered that heavy ice 

 from the Arctic takes anywhere from 

 one to probably two or three years to 

 make the journey to the steamers" tracks 

 one cannot trace the increase or decrease 

 in quantity or size of the bergs to the 

 Gulf Stream. 



Doubtless the stream varies in velocity 

 at different seasons of the year because 

 the trade winds vary periodically in 

 strength and direction. In the winter 

 months, when the northeast trades are 

 stronger, they blow from a more north- 

 erly direction and at the same time do 

 not extend to as far a northern latitude 

 as in the summer. During the latter 

 period they have a direction more nearly 

 toward the west, and although weaker in 

 force probably contribute more water to 

 the Gulf of Mexico . and hence to the 

 Gulf Stream than do the winter winds. 



These changes in the winds, however, 

 are felt in the Gulf Stream by a gradual 

 increase or decrease in its speed some 

 time after, the maximum yearly strength, 

 for example, coming in October, while 

 the maximum trade-wind influence is in 

 July and August. 



A temporary or a local increase or de- 

 crease in the force of the trade winds 

 would have but little eft'ect on the Gulf 

 Stream, because the current is due to the 

 average condition of the wind over an 

 area of hundreds of thousands of square 

 miles, and this average does not change 

 materially year by year. 



Sometimes a low barometer in the Gulf 

 of Mexico, accompanied by an abnormal 

 high on the southern Atlantic coast, will 

 cause a reverse flow on the sides of the 

 stream in the Straits of Florida for a 

 short time, but the vis-a~tergo of the 

 great mass of water quickly reestab- 

 lishes the normal current. 



There is every evidence that the Gulf 

 Stream is governed absolutely by law in 

 all its variations ; its course through the 

 ocean is without doubt fixed ; its fluctua- 

 tions are by days, by months, by sea- 

 sons, or by years, but they do not vary 

 materially one year from the other. So 

 we may conclude, of all the physical 

 forces on this earth that are subject to 

 any variations at all, the great ocean cur- 

 rents are most immutable. 



778 



