Management of Light in Illumination. 205 



Hence it appears that where 300 of light are 

 wanted it may be furnished by purified oil of colza, at 

 less than one third part of the money it would cost 

 when produced by means of the best tallow candles, 

 and at a very little more than one tenth part of the sum 

 it would cost if furnished by wax candles. 



These computations may serve to give some idea of 

 the immense importance to society of the subject I have 

 endeavoured to investigate in this Essay. 



[This paper is printed from the English edition of Rumford's Essays, 

 Vol. IV., pp. 1-126.] 



