268 Pearasll on the Communication of 



bodies, not as yet known to possess this power, might have it 

 conferred upon them. 



The restored effects which I have described, as produced 

 upon some known phosphori, in the former paper, I found to 

 occur with the class generally; and the following ordinary 

 substances will afford illustrations of the facility with which 

 phosphori may, as it were, be created in ordinary substances by 

 the means in question. The fragments used were placed in 

 the cavity of a piece of ivory, into which were inserted two 

 wires, and regulated discharges passed through them from a 

 Leyden jar, having about two square feet of coated surface. 

 The electrified portions were usually submitted immediately 

 afterwards to a strong heat, so as to exhibit the whole effect 

 of the phosphoric light with the utmost intensity. 



White statuary marble yielded no light in its natural state ; 

 after twelve discharges it was heated on platina, and gave a 

 dull orange light. 



The same marble, calcined at a red heat, and electrified by 

 twelve discharges, gave a clear orange and violet light by 

 heat. 



The carbonaceous part having been dissipated from ivory 

 calcined, a lilac coloured light was conferred by fourteen dis- 

 charges of electricity. This substance was, however, feebly 

 luminous when heated in its natural state. 



Mother of pearl calcined, and twelve times electrified, when 

 heated, gave a strong light of pink, violet, and light blue 

 colours, the whole of which were occasionally visible upon 

 different parts of the same fragment. 



Calcined oyster-shells, heated, after fifteen discharges emitted 

 a strong light, of considerable duration, with orange, yellow, 

 and lemon-green colours. 



Cuttle-fish bone calcined, after six discharges, was capable 

 of evolving by heat a bright lilac and violet coloured light ; 

 twelve discharges gave distinct pink, purple, arid yellow phos- 

 phorescent light. 



Common scollop shells were calcined and subjected to twelve 

 discharges of electricity : the application of heat disengaged a 

 strong light of considerable permanence, blending salmon, j)ink t 



