193 Mr. Mob. can's Ohfervations and Experiments on 

 proportion to this perfe£tion. There are flames, however, 

 which confift of burning particles, whole rays have partly 

 efcaped before they afcended in the form of vapour. Such 

 would be the flame of a red-hot coal, if expofed to fuch a heat 

 as would gradually difperfe it into vapour. When the fire is 

 very low under the furnace of an iron foundery, at the upper 

 orifice of the chimney a red flame of this kind may be feen, 

 which is different from the flame that appears immediately after 

 frefh coals have been thrown upon the fire ; for, in confe- 

 quence of adding fuch a fupply to the burning fuel, a vafi: 

 column of fmoke afcends, and forms a medium fo thick as to 

 abforb mofl of the rays excepting the red, 



"Experiments on eleSiric light. 



If we would wifh to procure any degree of certainty in any 

 hypothefis which we may form concerning ele£lrical light, 

 perhaps the following general dedu£lions may be of fome fer* 

 vice to us. 



1. There is no fluid or folid body in its pafTagc through 

 W'hich the eledlric fluid may not be made luminous. In water, 

 fpirits, oil, animal fluids of all kinds, the difcharge of a Ley- 

 den phial of almofl any fize will appear very fplendid, pro- 

 vided we take care to place them in the circuit, fo that the 

 fluid may not pafs through too great a quantity of them. My 

 general method is to place the fluid, on which I mean to make 

 the experiment, in a tube three-quarters of an inch in diameter, 

 and four inches long. I flop up the orifices of the tube with 

 two corks, through which I pufh two pointed wires, fo that the 

 points may approach within one-eighth of an inch to each 

 2 other. 



