116 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



PRELIMINARY REPORT UPON THE CURRENT OBSERVATIONS IN LONG ISLAND SOUND. 



1'>Y E. K. Haskki.i.. 



The olKservations for this disciissioji were made during the summer of 1890, from 

 the II. S. Steamer Finli Bank, during a joint iuveatigation l>y the U. 8. Commission of 

 Fish and Fisheries and the V. S. Coast and Geodetie Survey, for the purpose of study- 

 ing the condition of and the circulation of the sea throngli Long Island Sound. 



For a knowledge of the tides that traverse the Sound wo placed at New London, 

 New Haven, and Willets Point — practically at each cud and the middle — a self- 

 registering tide gauge. With the tide gauges in operation, wo made from the steamer 

 Fish Hmi'h a series of current observations, occupying therefor current stations 

 which in location give a cross section near each end of the Sound ; a current station 

 about every 10 miles in the lonyitudinal axis of tlie Sound; and a current station on 

 each of tlio dnui])iug-grounds of the towns of New Haven, Milford, Bridgeport, Nor- 

 walk, and Stamford. 



In illustration of the tides of the Sound, the moan establishment of Block Island 

 and that of Sandy Hook are about the same, namely 7'' 31'" and 7'' 35'", respectively. 

 There being but about ten minutes difference in time, due to difference in longitude, 

 it is practically high water at both places at the same time. From these places 

 the tide wave that causes high water travels by two different channels, the Block 

 Island branch through Long Island Sound from its eastern entrance, and the Sandy 

 Hook branch passing through New York Harbor and East River into the Sound from 

 its western entrance, and give to this inland channel a compcuind tide. 



From our observations, which confine us to the reach from New London to Willets 

 Point, Ave find it is high Avater at Ncav London (the mouth of the Thames) 9'' 47'",. at 

 NcAv Havcm (Light-IIonso Point) 11'' 17"', and at Wiliets Point 11'' 24'" aft.T the 

 moon's transit. The opposite phase of the tide takes place at Ncav London 3'' 31'", 

 at New Haven 5'' 03'", and at Willets I'oint .5'' 45"' after the moon's transit. These 

 figures giv(^ for the duration of rise 6'' IG'", 6'' 14"', and 5'' 39'" for New L(mdon, N»iw 

 Haven, and Willets Point, respectively; and, for the corresponding duration of fall, 

 C 08'", C'lO'", and 6'' 45'". 



The distance from Ncav LoJidon to Now Haven, moasui'od on a central line through 

 the Sound, is 36 nautical miles, and the distance from Ncav Haven to Willets I'oint, 

 measured on the same course, is 48 nautical miles. From the mean establishment of 

 these points, given above, and iXw eorresj)ouding distances botAveen them, it appears 

 that tiio tide wave travels from New London to Ncav Haven in 1'' 33'", or at the rate 

 of 23 nautical miles per hour, Avhile it travels from Ncav Haven to Willets Point in 

 10'", or at the rate of 288 nautical miles per hour. This remarivable difference in 

 speed of the Avave in these tAvo reaches is undoubtedly caused by the interference of 

 the tAvo waves that have arrived on the scene by the tAvo different routes. It is tlie 

 meeting-ground; or, to bo more oxidicit, the reach from Hell Gate to Stratford Sboi.1 

 is Avhorothe energy oftuo.se Avaves, traveling in opposite directions, is spent. 



An interesting feature in the tide of the Sound is the vertical motion of the water 

 that takes place. Mean sea level at .ill points throughout this Avater course is at 

 the same elevation, and might be represented by a straight lino so far as the pi'esent 

 discussion is concerned. At NeAV London the average rise of the tide is 2.(1 feet,, or 

 it has a semi-amplitude in its oscillations above and below the straight line repre- 

 senting mean sea level of 1.3 feet. At Ncav Haven the average ri.«e of the tide is 6 

 feet, or its 8emi-ain])lltude is 3 feet. At Willets Point the average rise of the tide is 

 7.3 feet, or its semi-amplitude in reference to the line is 3.05 feet. These figures 

 show that Avith every tide the water surface of the Avestern jtorticm of the Sound 

 is alternatoly made a hill and a hollo av when compared to the Avatcr surface in 



