THE ELECTROPHORUS. 579 



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of which unbleached shellac consists. Care must be taken, by con- 

 stant stirring, that the small lumps which are formed on each ad- 

 dition, should quickly dissolve in the liquid mass; as soon as each 

 lump is dissolved more shellac is to be added, for if too much time 

 is lost the liquid becomes too hot and then forms a mass resembling 

 india-rubber, which cannot be again liquefied and is therefore useless. 

 When all the shellac has been added, the pot is removed from the 

 fire, the mass once more briskly stirred so as to render its consistence 

 quite uniform, and to remove from the surface any film of melted wax, 

 and the whole is poured into the mould formed by the rim of paper. 

 After a few hours, when the cake is quite cold, the paper is torn off 

 as far as possible, and the cake lifted from the form ; if it adheres in 

 some places, the metal is; slightly pressed from below and the flexure 

 of the metal will help to free the cake. The utmost care must be taken 

 not to drop it, as it is rather brittle and easily broken. The paper 

 which has not come off at first may be removed by wetting it and 

 rubbing it off with the finger, or it may be left on without disadvan- 

 tage. 



In using the electrophorus, the form is placed beneath the cake 

 in the way just described, that is, bottom upwards, and the cake is 

 placed upon it so that the flat side which was in contact with the 

 form when the cake was moulded, is now uppermost. Formerly, 

 the form was used differently, its bottom resting on the table, the 

 cake was poured into the interior, hence its name ' form.' But the 

 cake, when firmly imbedded in the mould, is sure to crack after 

 some time, while a loose cake lasts indefinitely if carefully handled 1 . 

 If it should break, it may be recast ; after breaking it into small 

 fragments these are melted in the same pot which served originally, 

 and which should be kept for this use, as it cannot be well cleaned 

 and used for any other purpose. The mass must again be constantly 

 stirred until it is uniform, before pouring it into the form. 



For the experiments the cake must be quite dry, and if possible 

 slightly warmed, not so much, however, as to make it soft. During 

 the winter care should be taken to warm it slowly, otherwise it is 

 liable to crack. It is best warmed by holding it at some distance 

 before an open fire. While striking the cake a few fingers of the 

 left hand are laid upon the edge, so as to prevent its sliding from 

 the form while the cat's fur is applied with the right hand. If a 

 fox's brush is used, it is held at the thicker end and the strokes are 

 applied quite slanting ; a cat's skin is held by the projecting points, 

 so that the furry side is outwards, and the cake is struck similarly, 

 not strongly, but so that the fur may briskly glide over the whole 

 surface of the cake. In dry air the cake will remain electrical for 



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