220 DEEP BOREHOLE SURVEYS AND PROBLEMS 



The apparatus suffices for plumbings up to 700 m. and can, 

 with corresponding cable lengths, be used for any depth. 



Test Plumbings. — Tests with the above dip measurer 

 in a pipe in a shaft of the Deutscher Kaiser works were 

 carried out to a depth of 350 m. and have yielded the same 

 results on insertion and extraction and on repetition. 

 These have been checked by surveys and give agreeable 

 results as far as comes into general practice. Since in this 

 method partially active errors are avoided, which would 

 make repetition results false, the conclusions to be drawn 

 from the tests are that for a well thoughtout, ingenious and 

 rapid working apparatus it is quite accurate and satisfies 

 all the demands of practice. It should still be mentioned 

 that the dip measurer is also applicable as a stratameter 

 for cores. Speaking of this instrument, after observing a 

 test, Prof. Haussmann of Aix says,^ ''The mathematical 

 and physical basis on which the appliance is constructed 

 permits us to recognize that it is free from inherent errors; 

 thus must it also yield correct results with increasing 

 depths." This accuracy fulfills the preliminary conditions 

 for the success of freezing shafts, i.e., by proving the course 

 of the boreholes. 



Surwel Gyroscopic Clinograph. — This remarkable device 

 marks the most recent practice in the adaptation of the 

 gyroscopic principle to the survey of borehole deflection. 

 The principal features of the well-known Sperry^ gyroscope 

 of navigation are applied. 



This apparatus consists of three main parts: (1) the box 

 level gage (Fig. 2, Plate XIV) ^ for ascertaining the vertical 

 inclination, which is placed uppermost of the three in the 

 apparatus ; (2) the film camera (Fig. 3) making simultaneous 

 moving-reel records above and below ; and (3) the lowermost 



1 Haussmann, K., Mitt. Markscheiderwesen, p. 60, Sonderdruck, 1914. 



2 Glazebrook, Sir R., "Dictionary of Applied Physics," Vol. 1, p. 421; 

 Vol. 4, p. 255; also British Patent No. 15,669/15; Rawlings, A. L., "The 

 Theory of the Gyroscopic Compass," p. 18, Macmillan & Co., Ltd., 1929. 



3 By the courtesy of the Sperry-Sun Well Surveying Company, Phila- 

 delphia. 



