same way that the Gulf Stream does for 

 Europe. 



The superintendent of the Coast Sur- 

 vey, Prof. A. D. Bache, between 1844 

 and i860 caused thousands of thermo- 

 metrical observations to be taken on hues 

 extending across the stream, from Key 

 West to well beyond ITatteras, reasoning 

 on the line of Benjamin Franklin's stud- 

 ies, that temperature alone could define 

 its limits, and that the warmest water 

 within these limits would be the axis or 

 the swiftest current. 



He found, liowever, that there were 

 l)ands or streaks of warm and cold water 

 in the stream, the cause of which was 

 attributed to irregularities in the bottom 

 over which it flowed, but this was 

 based upon erroneous measure- 

 ments of the depths, for in later 

 years, with wire sounding lines 

 instead of rope, the bottom' has 

 been found to be nearly even. 



For ascertaining the relative ve- 

 locity of the Gulf Stream between 

 the surface and subsurface on a 

 given line, trials were made by 

 floating a single can almost sub- 

 merged on the surface and a pair 

 of cans,; one on the surface-and- 

 the other suspended by a cord at df.vgram 

 a given depth below. If both 

 were started together, one being 

 only influenced by the surface cur 

 rent and the others beins: in 



SHOWING THK METHOD OF OliT.MXING 

 THK CURRKXT OnSI^RVATlONS OX JiOARD 



THii "bi.ake;" 



The current meter at the end of the wire on the 

 right, slides down another larger wire having at its 

 i""" "V '1 "^ Ti ""^""V -— -is — gnd a heavy leaden weight, which in turn is restrained 

 itucncea Dy tne surtace ana tne ^^^^ ^^^^„ g^^^p^ astern by the force of the current 

 subsurface as well, the retarding by a long line secured to the anchoring rope. 



>r accelerating efi:"ect of any difl'er- 

 ence in velocity might be determined. 



In 1883 the Coast Survey Office de- 

 cided to attempt to anchor a vessel in 

 the Gulf Stream and to actually measure 

 the amotmt of water flowing past. It 

 was thought that this might be accom- 

 plished by the use of wire rope instead 

 of a hemp cable or chain, both on account 

 of its strength and flexibility, and also 

 l)ecause it could be made in great lengths. 

 The first trial at anchoring in the Gulf 

 vStream was made by the little Coast Sur- 

 vey schooner Drift, but with no steam 

 l^ower to handle the wire rope anchoring 

 line the difficulties were great. The re- 

 sult of this first attempt was the detail of 

 a Coast Survey steam vessel, the George 

 S. Blake, for the Gulf Stream work. 



.-V new departure was then made from 

 the ordinary method of anchoring in very 

 deep water. A great length of wire rope 

 (over 414 miles) was carried on a large 

 iron reel or spool. A powerful steam- 

 engine, running a winch, lowered and 

 raised the wire rope with its anchor, 

 while another engine revolved the spool. 

 A special arrangement of rubber bufifers 

 was applied to the anchoring rope, 

 Avhereby the sudden strain, due to violent 

 pitching of the vessel, was reduced to a 

 minimum. By this system the Blake was 

 able to anchor in almost any depth of 

 water, and did anchor in depths of more 

 than two miles many times. 



To gain a knowledge of the laws gov- 

 erning the flow of any current, it is neces- 



773 



