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Jahresbericht Hr. 9/1954 
In the magnetic compass laboratory the necessary minimum protective 
distance from the magnetic compass was fixed, by experiment, for various 
instruments or parts of instruments installed in the wheel houses such as 
electrical driving equipment for hand rudder, electrical indication systems 
for rudder positions and constructional parts of echo sounding equipments. 
With the aid of a newly built horizontal vibrator -table some gyro compass 
stands and compass bowl spring suspensions were tested. In future a flash 
light stroboscop will supply elucidative results for the investigation of 
rapid mechanical swinging processes. Onboard of surveying and research ship 
"Gauss" further recordings of the rolling and pitching motions, of the ver 
tical accelerations and of the rolling angle between true and false vertical 
line were carried out. The section is busy to develop a suitable method to 
analyse electrical frequencies and amplitudes of the won recordings. 
In the field of sonic sounding machines the testing of two modern types 
of recording sonic sounders on behalf of the industry was carried out over 
deep water, and on this occasion investigations with transmitting oscilla 
tors of different frequencies and directivity were made. In addition to this- 
the changes of the depth down to which the sound goes, the discrimination 
and the recording quality of fish and bottom echoes of ordinary recording 
sonic sounders in relation to the pulse output and pulse length were 
examined. During several cruises of the surveying and research ship "Gauss" 
the nature of the bottom of the western Baltic, of the Baltic entrances and 
of the Kattegat were surveyed with recording sonic sounders. 
Minute tests of a number of radio direction finding equipments of 
various make, representing navigational aids, were made at sea under con 
ditions of field operation. In addition repeated,control trips were carried 
out with craft of the Institute to determine, for the purpose of statistics, 
the average accuracy and stability of position fixes of the German Becea 
chain. Furthermore, the North Sea Consol radio beacons were observed, by 
recording, as to their stability of position fix” in a near and distant range. 
The same as last year, the number of instruments and position lanterns 
submitted to the Hamburg office and agencies of the Institute to be tested 
and the enquiries answered increased again with the growing merchant fleet. 
A committee constituted at the suggestion of the "Ausschuß des Seeverkehrs- 
Beirats für Angelegenheiten des D.H.I." and which is composed of representa 
tives of the industry, of the "See-Berufsgenossenschaft", schools of navi 
gation, and of the "Deutsches Hydrographisches Institut", is at present 
engaged in revising the testing regulations of the G.H.I. for the single 
instruments. 
In the library and in the Archives the exchange of publications with 
German and foreign exchange”partners was further built up, The Library 
could list progress in their work of entering the publications in cata-