from Terrestrial Sources, 53 



Phil. Journ, No. xix. p. 123.) This experiment gave a corre- 

 sponding increase of ratio when the density of the flame was thus 

 increased. 



Another very striking instance is found in the phenomenon 

 observed by Count Rumford and Mr. Brande, that the quantity of 

 light is increased by placing several flames near each other, or so 

 as to coalesce. Count Rumford considered the cause of this to be 

 that the flames thus communicated heat to each other, or, in other 

 words, that a portion of the heat otherwise radiated away, was 

 retained. This then, it would seem, is engaged in some way in 

 the greater extrication of light. To this phenomenon I applied 

 the same method of observation, and found the ratio increase as 

 it should do, if we could assume that the heat radiated increases in 

 proportion to the temperature of the flame. For Count Rumford 

 found the light to increase in much greater proportion [than the 

 temperature of the flame. 



I found, for example, that when two flames of wax candles were 

 made nearly to coalesce, the heating power of the light was con- 

 siderably more than double that from one of the flames, whilst the 

 radiant heat was less than doubled. 



A series of trials ivith incandescent iron, gave a decrease of 

 ratio corresponding to the degree of cooling, till the mass ceased 

 to be luminous. 



9. In Mr. Brande's paper, before referred to, one of the most 

 interesting and important results, is the fact, that the chemical 

 power possessed by the solar rays is not found in any sort of ter- 

 restrial light, except that produced from intense galvanic action. 

 This would seem to indicate that galvanic light forms a term in 

 the series, approaching more nearly to the solar light, than the 

 most intensely luminous flame ; and, since the law of inverse pro- 

 portionality between the two radiations continues through all the 

 instances of combustion, and is again exhibited in the solar rays 

 when the proportion of the radiation of simple heat has become 

 insensible, it is most probable, that if the galvanic radiation were 

 examined by the method above proposed, we should find, corres- 

 ponding to its resemblance, in chemical power, an increase in the 



