196 



CHAPTER III. 

 PEACTICAL CONSIDEEATIONS. 



To those reflective minds who really enjoy the beau- 

 ties of nature and contemplate them with admira- 

 tion, practical details are of so little interest, that 

 I had not the intention of saying anything upon 

 the subject in this work. But, as some persons 

 endeavour, at any risk, to turn everything to pro- 

 fit, to make everything in nature useful to man 

 in one way or another, I am willing to show that 

 phosphorescence is far from being devoid of uti- 

 lity, and that it has already been extensively ap- 

 plied to various uses, often without a knowledge 

 of the fact. 



It would, indeed, be superfluous here to dilate 

 upon the uses of light ; it will be sufficient for me 

 to state that the most powerful light ever pro- 

 duced by man, without exception, is owed to a 

 phenomenon of phosphorescence. I allude to the 

 " Drummond, or Lime-light." 



It is produced by submitting lime, a highly 



