II. MINING. 737 



3403. Two Maps with Photographs of mine surveying 

 Instruments. C. Osterland, Freiberg. Saxony. 



3404. Small Theodolite, with repetition for mine surveyors. 

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



and E. Schramm). 



3405. Compass Attachment to the Theodolite. 



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

 and E. Schramm). 



3406. Mine Theodolite with repetition, 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 border 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 Son. 



Royal High School of Industry at Cassel. 



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

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

 the protection of the division, the covering also invented by Breithaupt, the 

 verniers of which are closed with glass. The vertical circle is placed opposite 

 to the telescope as a counterpiece. On the cylinder of the telescope axis a 

 compass and a spirit-level can be placed. The spirit-level of the telescope 

 serving for levelling lies with cylindrical pivots in bearers in front of the 

 latter, and when the telescope is folded down it may be again turned upwards 

 and -observed. This theodolite also forms a convenient small universal in- 

 strument for astronomical observations. It has already been described in the 

 fourth part of the " Magazin Mathemr tischer Instrumente," published by 

 Breithaupt's establishment in the year IS 60. A similarly constructed eccentric 

 mining theodolite, referred to in 1876jby Prof. Bauernfeind, in his " Vermes- 

 suugskunde," has been made by Ertel, of Munich. 



SAFETY LAMPS. 

 340 7 a, Davy's Original Safety Lamp. Royal Society. 



39508. 3 A 



