- Seite 74 — 
Jahresbericht fir.12/1957 
physical Tear, Horizontal and. mixing processes were observed under this 
aspect as preliminary work of the task assigned to the D.H.I. to keep a 
check on radio-active substances in the. sea water. 
The Tide-Tables for the year 1957 appeared as heretofore in two volumes. 
Volume I "Europäische Gewässer" amplified by detailed predictions for two 
Norwegian standard ports, namely Narvik and Bergen. Volume II having so far 
covered the Atlantic and the West Indian Ocean will for 1958 be extended to 
the entire Indian Ocean and to Australia. The calendar showing the times of 
high and low water for the German Bight and its river estuaries appeared as 
hitherto. There- has been'as continuous brisk demand for the "Atlas der Gezei- 
tenstrome für die Nordsee, den Kanal und die Britischen Gewässer" which has 
been published the year before. The new methods which had been developed 
during the last years for the analysis of the tides and for the computation 
of tide-tables by using punch cards machines could also be sucessfully applied 
in the meantime to the times of high and low water at Dutch and Indian ports.- 
The photographic zenit telescope having an aperture of 250 mm and a 
focal distance of 3 750 mm was completed and taken into operation middle of 
September for time and latitude determinations. 
The D.H.I. has taken part in the comparison of existing methods of radio- 
position fixings carried out by the "Ausschuß für Funkortung" and by the ' 
"Naehrichtentechnische Gesellschaft". Besides the D.H.I. attended the Three- 
Nation Meeting in London where it cooperated -in the question of protection 
against collision by radar or other electronic aids. Thanks to the good 
offices of the "Funkortungsausschuß" as well as due to the kindness of the 
DEBBG the most important innovation in this field, the true motion radar 
(Kursradargerät) could be demonstrated during several days on "Gauss" to the 
representatives of all circles interested in shipping. 
From amongst the great number of investigations in the field of nautical 
engineering the most important ones may be brought into prominence: the deter 
mination of minimum protective distances from the magnetic ship's compasses 
of instruments serving navigation on radio aids and the study of the dynamic 
error at magnetic compasses, the latter having led to a draft for supplement 
ing existing testing regulations; measurements of inclinations and accelerat 
ions caused by the motion of the ship due to the sea as well as testing of 
sounding machines, all within the compass of preparatory work for the Inter 
national Geophysical Tear,-. 
In the Fachnormenausschuß "Farbe" (Special Committee on Standardization 
"Colour") the leaflet "Farben und Farbgrenzen für Signallichter an Wasser 
fahrzeugen" (Colours and limits of colours for signal lights in water craft) 
has been elaborated. After having laid down the new limits, the Scandinavian - 
countries were approached with the object to bring these new colour limits in 
to accord with the regulations being prepared there. Examinations of radio-