on Galvanometers. 81 



which are used ballistically it has been found convenient to 

 provide a damping-coil, operated with an auxiliary small cell 

 and roughly-made reversing-key, for the purpose of expediting 



Fig. 12. 



Perspective elevation of Ballistic Galvanometer with brass case removed. 



measurements, we think that such a damping-coil should be 

 attached, by the makers, to every ballistic galvanometer. 



The brass case, K, has hinged brass doors D, J), D, D at 

 its sides, to protect the glass windows ; and both doors and 



Phil. Mag. S. 5. Vol. 30. No. 182. July 1890. G 



