jJ6 OX THE HEAT EVOLVED 



article, in their usual states of aggregation, was found to be only 

 three per cent. 



It is proper to state that the experiments were made with 

 the best quality of every article that could be procured, and 

 as some slight difference may exist between wood of different 

 ages, the medium sizes were selected. Those woods and coals 

 which are peculiar to the New England States, were obtained 

 from thence. The Rhode-Island and Worcester coals were 

 procured for me by an obliging friend in Boston, who stated 

 that the coals were selected with care, but, that the Worcester 

 coal being a recent discovery, and the parcel sent having been 

 taken from the surface of the bed, could not be considered as 

 a fair sample of the coal which may be supposed to exist in 

 lower strata. 



Many and insuperable difficulties presented themselves, in 

 attempting to ascertain by common methods the weight of 

 dry wood in a cord of each kind. The plan adopted, and 

 which appeared most likely to produce satisfactory results, was 

 as follows. From a pile of swamp white oak of medium size, 

 which had been cut the preceding winter, and weather seasoned 

 during the interval, (this being the state in which the largest 

 portion of wood is sold.) a half cord, or sixty-four cubic feet, 

 was accurately measured, and its weight was found to be 1928 

 avoirdupois pounds. From this half cord was taken in various 

 sizes, a sufficient number of sticks to allow one piece to be 

 sawn from each, twelve inches long, to produce j z part of the 

 whole weight, which being done, the pieces of wood were placed 

 in a foot " corder" or space twelve inches square, made by nail- 

 ing four pieces of board together at the ends ; but the wood 

 not being found to fill it equally in the first instance, other pieces 

 were substituted, of equal weight, until the interstices between 

 the sticks presented a similar appearance to that of wood, as 

 ordinarily piled up for sale. 



This parcel of wood was then perfectly dried in an oven, 

 and its solid content ascertained by the quantity of water 

 which it displaced. To perform this operation, a tin box was 

 used, fifteen inches deep, and six inches wide at the open top. 



