178 DEEP BOREHOLE SURVEYS AND PROBLEMS 



The camera is 32 in. long and 3^{ e by l^i in. in cross- 

 section. It is fitted with a 9-in. Bausch & Lomb rectilinear 

 lens. The camera^ is so placed in the tube as to photo- 

 graph the 4:}^ in. of wall reflected in the mirror upon 3^^ in. 

 of film, the maximum length obtainable with a width of 

 film of 1^^ in. This reduction gives a photograph eight- 

 tenths full size. 



The camera is fastened in the tube by two thumb screws. 

 One side of the camera is fitted in grooves and is easily 

 removed for changing the film. The film winds from the 

 end roll i (Fig. 117) across the flat plate for exposure and 

 is wound upon the other roll j by the operation of the 

 electromagnet h (Fig. 116) acting through an arm and 

 pawl upon a ratchet wheel. The wires for the coil have a 

 plug connection at the bottom end of the camera. A 

 three-core cable of No. 14 wire and 250 ft. long carries 

 the current from four small double-storage cells. A resist- 

 ance coil is used to adjust the voltage for the lamps before 

 lowering the camera tube. Connection from the cable 

 to the battery and switches is made by a triple plug in the 

 end of the shaft of the winding drum. The hoisting cable 

 is a heavy line of small twisted wires, tested to over 500- 

 Ib. tension. The drum is wound with 300 ft. of this 

 cable, and has length tags soldered to it at 5-ft. intervals. 

 The ratchet on the drum has a double pawl permitting of 

 3-^-in. changes in the position of the camera tube. No 

 attempt has been made to record the direction in which 

 the camera hangs. This could be done by an orientating 

 coupling rod or by mounting a magnetic needle to show 

 in the photograph. Good photographs can be taken in a 

 well hole both above and below water. The camera has 

 been operated in a 200-ft. prospect hole 6 in. diameter 

 upon the Vinegar Hill Mining Company's property, about 

 7 miles north of Galena, Illinois, at a depth of 162 to 200 ft. 

 when the water stood at about 85 ft. from the surface. 



The first attempt in taking photographs under water 

 was entirely successful. The camera was filled with air 



1 Eng. Min. Jour. Press, p. 944, May 18, 1907. 



