Dana on Flame. : 401 
od 
Art. XV. On the Effect of Vapour on Flame. By J. F. 
Dana, Chemical Assistant in Harvard University, and Lec- 
turer on Chemistry and Pharmacy in Dartmouth College. 
~ i *# 
Cambridge, Mass. February 5, 1819. 
To Professor Silliman. 
DEAR SIR, 
Apour a year since | made some experiments onthe effect 
of steam on ignited bodies, with a view to learn the theory of 
the action of the “ American water-burner.” ‘These experi- 
ments were published in an anonymous paper in the North 
American Review, and have been published in London, with- 
out an acknowledgment of their source. 
The effect of them concerning bodies is peculiar, and it 
probably admits of more extensive application to the arts than-— 
in the above named instrument alone. 
When a jet of steam, issuing from a small aperture, is 
thrown on burning charcoal, the brightness is increased, if the 
coal be held at the distance of four or five inches from the 
pipe through which the steam passes; but if the coal be held 
nearer it is extinguished, a circular black spot first appears 
where the steam is thrownon it. The steam in this case does 
not appear to be decomposed, and the increased brightness of 
the coal depends probably on a current of atmospheric air, 
occasioned by the steam. But when a jet of steam, instead of 
being thrown on a single coal, is made to pass into a charcoal 
fire, the vividness of the combustion is increased, and the low 
attenuated flame of coal is enlarged. 
When the wick of a common oil lamp is raised, so as to 
give off large columns of smoke, and a jet of steam is thrown 
into it, the brightness of the flame is increased, and no smoke 
is thrown off. 
When: oil of turpentine is made to burn on a wick, the 
light produced is dull and reddish, and a large quantity of thick 
smoke is given off; but when a jet of steam is thrown into 
