II. HYDROGRAPHY. 731 



II. HYDROGRAPHY. 



ADMIRALTY HYDROGRAPHIC DEPARTMENT. 



DEEP-SEA SOUNDING AND DREDGING APPARATUS, AND 

 SURVEYING INSTRUMENTS, USED IN H.M.S. " CHALLENGER," 

 1872-6. EXHIBITED BY THE HYDROGRAPHICAL DEPART- 

 MENT, ADMIRALTY. 



2971a. Altitude and Azimuth instrument, 8-inch. 



Repeating circle. 



Theodolite, 6^-inch. 



Sextant, observing. 



Sextant, sounding. 



Sextant, pocket, or box. 



Micrometer telescope, 24-inch. 



Station pointer, 6-inch. 



Protractor, circular. (Bullock.) 



Protractor, semi-circular. 



Protractor, rectangular, 12-inch. (Metal.) 



Protractors, rectangular, 8-inch. Case of three. 



Scale, brass, graduated, 3 feet. 



Straight-edge, steel, 6 feet. 



Parallel rulers, 12, 18, and 24 inch. Case. 



Sector. (Metal.) 



Mathematical instruments. Case. 



Baillie weight detaching apparatus, date 1872. By 

 Nav. Lieutenant C. W. Baillie, R.N. 



Hydra weight detaching apparatus, 'date 1868. By 

 Gibbs, Artificer, H.M.S. "Hydra." 



Tube lead, 1 cwt. For sounding in depths not exceeding 

 1,000 fathoms, and procuring bottom specimen, date 1872. 



Cup lead, 1 cwt. For sounding in depths not exceeding 

 1,000 fathoms, ami for procuring bottom specimen, date about 

 1858. 



