II. MINING. 875 



3393. Complete Mine Surveying Instruments, consisting 

 of compass, suspender, protracting clinometer plate, pocket and 

 case for the additional plate. Otto Fennel, Cassel. 



3402. Mine Theodolite (No. 159), with stand and leather 

 case. Otto Fennel, CasseL 



Differs from the preceding principally in the apparatus for adjusting the 

 telescope. *** 



3403. Photographs of mine-surveying instruments. 



C. Osterland, Freiberg, Saxony* 



3404. Small Repeating Theodolite for mine surveyors. 

 A. Lingke and Co., Freiberg, Saxony (M. Hildebrand 



and E. Schramm). 



3405. Compass Attachment for the Theodolite. 



A. Lingke and Co., Freiberg, Saxony (M. Hildebrand 

 and E. Schramm). 



3406. Mining Repeating Theodolite, with 



a. Box compass. 



b. Two separate tripods. 



c. Two signals. 



d. Two signal lamps. 



e. Suspender and appurtenances to the compass. 



F. W. Breithaupt and Son, Cassel (G. Breithaupt). 



With horizontal circle 12 cm. in diameter, and silver limb graduated 

 into half degrees, the vernier indicating minutes and is covered with glass ; 

 the vertical circle and vernier are similarly divided, provided with transpa- 

 rent signals for use either below or above ground. The suspensory apparatus 

 attached to the setting up compass was constructed by F. W. Breithaupt for 

 the survey of the Hartz. 



3407. Mining Theodolite, by Breithaupt and Sou. 



Royal High School of Industry, Cassel ( W. Narteri) 



Mining Theodolite, with lateral telescope, constructed by F. W. Breit- 

 haupt and Son in 1864. The two circles are divided upon silver and are 

 protected by the covering invented by Breithaupt, the verniers also are 

 enclosed in glass. The vertical circle is placed opposite to the telescope as a 

 counterpoise. On the cylinder of the telescope axis a compass and a spirit- 

 level can be placed. The spirit-level of the telescope for levelling lies with 

 cylindrical pivots in bearers in front of the latter, and when the telescope is 

 turned over it may be again turned upwards and observed. This theodolite 

 also forms a convenient small universal instrument for astronomical observa- 

 tions. It has already been described in the fourth part of the " Magazin 

 Mathematischer Instrumente," published by Breithaupt' s establishment in the 

 year 1860. A similarly constructed eccentric mining theodolite, referred to in' 

 1876 by Prof. Bauernfeind, in his " Vermessungskunde," has been made by 

 Ertel, of Munich. 



SAFETY LAMPS. 

 3407a. Davy's Original Safety Lamp. Royal Society. 



