86 THE NATURE OF ANIMAL LIGHT 



Receiver, so as it was kept from touching the Cement; 

 and the Pump being set a-work, we observed not, during 

 the 5 or 6 first Exsuctions of the Air, that the splendor 

 of the included Wood was manifestly lessened (though 

 it was never at all increased;) but about the 7th Suck, it 

 seemed to glow a little more dim, and afterwards answered 

 our Expectation, by losing of its Light more and more, as 

 the Air was still farther pumped out ; till at length about 

 the 10th Exsuction, (though by the removal of the Candles 

 out of the Boom, and by black Cloaths and Hats we made 

 the place as dark as we could, yet) we could not perceive 

 any light at all to proceed from the Wood. 



**Exp. II.: Wherefore we let in the outward Air by 

 Degrees and had the pleasure to see the seemingly extin- 

 guished Light revive so fast and perfectly, that it looked 

 to us almost like a little Flash of Lightning, and the Splen- 

 dor of the Wood seemed rather greater than at all less, 

 than before it was put into the Receiver.'' 



Boyle proved that light from the wood was able to pass 

 a vacuum and later showed that *' shining fish" behaved 

 as the ' ' shining wood, ' ' but that a piece of white hot iron 

 would not regain its light on readmitting air to the ex- 

 hausted receiver and that the iron lost its glow under the 

 air-pump merely because it cooled off. A piece of glowing 

 coal, however, did lose its light in the absence of air and 

 regained it on again admitting air, provided the air had 

 not been removed for too long. Boyle was apparently 

 impressed with the similarity of the light giving process 

 in glowing coal and shining wood as he draws a compari- 

 son between the two which brings out the fundamental 

 similarity of combustion processes. 



