and in the Condensation of Vapours. 375 



out the least smell of ether being diffused through the 

 room ; and it was in these instances alone that I con- 

 sidered the experiments as accurate. 



As to wood, I have found a very simple method of 

 burning it completely, without the least appearance of 

 smoke or smell. I got a joiner to plane me shavings 

 about half an inch wide, a tenth of a line thick, and six 

 inches long ; and holding these in the hand or with 

 pliers, elevated at an angle of 45 or thereabout, and 

 with the edges perpendicular, they burned like a match, 

 with a very clear flame. 



The slip of wood that burns being very thin, and placed 

 between two flat flames which press on it closely, it is 

 exposed to the action of so strong a heat that it burns 

 perfectly and entirely. 



If the shavings employed be too thick, a portion of 

 the charcoal of the wood remains, particularly if it be 

 oak, or any other wood of slow and difficult combus- 

 tion ; and in this case the experiments are defective. 

 But if the shavings be sufficiently thin, and well dried, 

 I have found that any kind of wood may be burned 

 completely. 



In burning candles, wax tapers, or fat oils in lamps, 

 the only precautions necessary are so to arrange the 

 wick as to yield no smoke ; to place the flame properly 

 in the aperture of the worm ; and to surround the 

 apparatus on all sides by screens, to prevent the flame 

 from being deranged by the wind. 



In these experiments there is one source of error, 

 too obvious to escape the most superficial observer, and 

 to which it was important to attend. While the calo- 

 rimeter is warmed by the heat developed in the combus- 

 tion of the inflammable substance which is burning at. 



