COMPARA TIVE EXPERIMENTS. 113 



Notwithstanding the importance of these documents, we 

 believe the question is far from having been settled, for we 

 find that in them the spirit of nationality has played so l?rge 

 a part that they cannot be implicitly trusted. Nor can we 

 rely on the figures given by the several makers and inventors 

 of the machines. Not only are the majority of these indi- 

 viduals without the scientific acquirements necessary for 

 exact result?, but there are personal interests the influence 

 of which it is impossible to eliminate from the statements 

 put forth, and for my part I believe that we must deduct a 

 great deal from the results which have been announced. 

 Amidst this confusion it is difficult to see where we are, and 

 it is much to be desired that an international commission 

 should undertake to completely clear up the question. In 

 the meanwhile we give the results obtained by the English 

 and American Commissions in the two tables on pages 123, 

 124, and 125, and to these we shall add a third table, drawn 

 .up by Shoolbred, from the most recent experiments. 



In order to define the values of the figures in these tables, 

 we must mention that the standard for light adopted in them, 

 and denominated a candle, represents the light of a spermaceti 

 candle, having an intensity equal to eight-tenths of the light 

 of a bougie de FE-toile. A Carcel lamp represents about 9! 

 candles (9*6). 



In the table of English measurements mention is made of 

 the condensed radiating power and of the diffused radiating 

 power. It is important that these expressions should be 

 understood. The condensed radiating power, as we have 

 already indicated on p. 21, is applied to the light given off 

 by a continuous current between two carbons, one of which 

 is hollowed out in a cup shape and so turned as to act as a 

 reflector, and to emit the light externally with increase of the 

 illuminating power. The diffused radiating power is that 

 which is produced by a light between two carbons without 

 a cup-shaped hollow. 



In the American table mention is made of foot-pounds : 



8 



