Compasses, Magnetometers. 



793 



60123. 1 : 12. 



60125. 1:10. 



60126. 1 : 10. 



60,121. Apparatus for Proving that the Total Free Magnetism is equal to Zero, Figure d. 

 (M. P. 10"' edn., IV, 1, Fig. 43) 0.12.0 



60,122. Compass (Friedr. C. G. Muller's) (M. T., Fig. 151) 



60,123. Compass (W. Weber's), Figure, graduated in 1 / i , on silvered brass ..... 

 A 20 cm diameter compass with a short powerful magnetic needle is fixed on a polished wood 

 rail, 1.5 m long, divided in centimetres. The needle is suspended on a raw silk fibre and carries a 

 long aluminium pointer and a sheet of mica swinging in a box, for damping purposes. The compass 

 can be moved up and down by means of a screw for the purpose of bringing the magnetic needle 

 into the axis of the magnets to be investigated. 



60,124. - - idem, graduated in 



on silver, with magnifying glass for reading 



60.125. - - idem, simple (M. P. 10 lh edn., IV, 1, Fig. 45; 9 th edn., Ill, Fig. 88), Figure 



60.126. Magnetometer (Salcher's), Figure (Ztschr. f. d. phys. u. chem. U. 3, p. 195), very 

 finely constructed, with 2 magnet suspensions in case and 6 bars of Swedish Charcoal Iron 



A graduated rail turns on a vertical pin, to which a cord pulley is firmly fixed. The rotary 

 bearing for the magnet bars to be tested and for the iron rods possesses a cord pulley of the same 

 size as the one just mentioned, being connected to it by a length of cord. On rotating the rail the 

 bar set up maintains its initial position to the magnetic meridian. The compass case and the disc of 

 the bar-bearing are graduated; the compass itself has a graduation in 1 / 5 on silver, read by a magni- 

 fying glass. The magnetometer is especially adapted for nautical schools. 



Of the 6 soft iron bars 1 each is 10, 15, 20 mm thick and 30 cm long, 1 each 25 and 30 mm 

 Iliick and 40 cm long, and 1 35 mm thick and 60 cm long. 



1.10.0 



7. 10. 



11. 0.0 



2. 5.0 



32.10.0 



Cl. 2047, 204S, 204. 



