( 569 ) 



At these researches wind and weather were on the whole favour- 

 able; the wind was in a few cases noted 7 at most, at which 

 force, however, the observations had to be put a stop to in Feb- 

 ruary 1906 1 ). 



On the plate added, the new measurements are again represented 

 graphically in central and progressive vector-diagrams. Also the central 

 diagrams, have been constructed this time with the aid of values 

 interpolated for full hours, the directly measured values however, 

 having still been indicated by dots. 



It is principally to give a full idea of the variability in direction 

 and velocity of the currents, that these diagrams of the new series 

 of observations have been reproduced fully here. 



Comparing the values of the velocity near the surface and in the 

 depth, we see that in 3 out of the 4 cases they show a rather 

 distinct decrease at an increase of depth. Also at the former series 

 of observations at H2 (3—4 Aug., 8—9 Aug. and 2—3 Nov. 1905 2 ), 

 also 8 — 9 Febr. 1905 3 ) ) the same result was arrived at. 



Also dilterences of phase in the periodical currents are noticed in 

 most cases between the surface and the depth, though a distinct law 

 may not immediately be obvious here. 



The striking difference in amplitude of the (idal currents during 

 the observations in August 1905 and February 1906 on the one 

 side and that of November 1905 and May 1906 on the other, is 

 certainly connected with the age of the tide, as it was with the first 

 nearly spring-tide (15 1 /; and 14 days after N. M.), with the last 

 nearer to dead neap (10 and days after N.M.). 



The small number of series of observations that can be disposed 

 of, does of course not allow at all to already think of a calculation 

 of tidal constants, nor to give a correct description of the average 

 variation of the currents. The unmistakable general agreement, 

 however, between the different current-diagrams justifies sufficiently 

 an attempt to compose them. As no doubt moon-tide will have played 



!) The reliability of the new observations is no doubt greater than that of the 

 former, if we take into consideration, that in August and November 1905 and in 

 February and May 190G the Wodan lay moored, so that her motion was conside- 

 rably smaller than on the former occasions, when she had cast only one anchor. 



It may still be mentioned that an experimental and theoretical investigation 

 was started about the influence of the movements of the ship upon the indications 

 of the current-meter, which, however, has not yet led to a satisfactory result. 



*j Publ. de Girc. N°. 26. 



:; ) . , . No. 36. 



