238 



M. N. Berdichevskii 



graphically on the plane-table by means of a scale rule and a geodesical 

 protractor. 



The 5th column has the magnetic azimuth of the measuring line calculated 

 from the formula Aj^js^ Aqq 90^ where -^jv/jy ^^ *^® magnetic azimuth of 

 the measuring line; 



Aqq is the magnetic azimuth of the section OQ connecting the centres 

 of the feed and measuring lines. 



1st feed line 



Fig. 7. 



In setting up the program of measurements, the azimuth of the feed line 

 was selected so that the angle was between the values 70-110°. Depend- 

 ing on the configuration of the road, the azimuthal probe was cai'ried out 

 with one or several azimuths of the feed line. For example, measurements 

 at the points within the limits of the section 1-2 of the road shown in Fig. 8, 

 were carried out with the direction of the feed line being A^ B^ . To carry 

 out naeasurements at the section 2-3, a second feed line A^B^ was used. 

 On changing from one direction of the feed line to another, the measure- 

 ments at one of the points placed near the point 2 were doubled so that 

 the sections of the KS curve obtained with different direction s of feed line 

 touched one another at one of the spacings. 



The dimensions of the measuring and feed lines satisfied the conditions 



MN < — R, AB < 0.6 R. 



The maximum length of the feed lines was 500-1500 m depending on the 

 conditions of the measurements. 



In the probe process the length of the feed line changed several times, 

 an attempt being made to keep this number of changes to a minimum. 

 When changing from one feed line to another, the measurements were 

 doubled, Avhich made it jDossible to combine the sections of the KS curve 

 obtained with different feed lines. 



A compass was used when unreeling the cable of the feed line, the max- 



