159 



lar experiments conducted in the same manner as the 

 above, on some of the common combustibles which are 

 used in New England, as determined by the writer of this 

 tract. 



Ibs. oz. 



Oak (white), (Quercus alba) dry - - 39 4 



do. do green - - 32 1 



Oak (yellow) (Quercus castanea) dry - - 41 7 



do. do. green - - 35 5 



Hickory (Gary a squmosa) dry - - 43 3 



do. do. green - - 40 



Maple (rock) (Acer saccharinum) dry - - 43 1 

 do. do. green - - 41 10 



Maple (white) (Acer dasycarpum) dry - - 39 

 Pine (white) (Pinus strobus) dry - 29 12 



do. do. green - - 22 



Pine (pitch) (Pinus rigida) dry - - 33 9 



do. do green - - 29 2 



Liverpool Coal - 80 



Lehigh Coal - - 89 4 



Rhode Island - 89 12 



Charcoal (oak) - - 97 1 



do. (pi ne ) - - 70 



The heating power of all the above woods s found to 

 be considerably augmented by drying them in a hot 

 oven. The wood, when burnt, was in the state of small 

 shavings. 



Heat is likewise produced by percussion, friction, and 

 the mixture o certain substances ; also by electricity, &c, 

 all of which with propriety we shall defer to another op- 

 portunity, and conclude this essay with the advice of a 

 great and good man. ' Tf.you would discover the hidden 

 causes of nature's grand operations, you must first learn 

 and elucidate those which are simple and of every day oc- 

 currence before your eyes. It is from small causes that 

 great effects are produced.' 



