326 Discover}/ of a Deposit of bituminous B'ood. 



the bark of the different trunks; its knots ; fracture; tlic 

 colour of some kinds ; the facihty with which it inflames ; 

 the alkah contained in its ashes ; — all these characters, very 

 distinct, render it perfectly similar to charred wood. 



** It must also be added, that it possesses this singular pro^ 

 pcrty, that it is susceptible of beino- worked in the lath with 

 the greatest facility, and of acquiring a polish and splendour 

 which render it superior to ebony. 



" In the last place, it is a conductor of the electric fluid, 

 and transmits it with facility." 



After this short account of the situation and nature of 

 this fossil, I shall describe some of the experiments which 

 the author made, in order to determine what advantages 

 may be derived from the employment of this substance. 



He burnt I'j pounds of this bituminous wood in a fur- 

 nace, adapting to it a thermometer at the distance of eight 

 inches, the temperature at the time being 10 degrees of 

 Keaumur. Sixteen minutes after, the whole wood was 

 completely kindled, and gave a clear brilliant flame, with 

 less smoke than coal and a slight odour of bitumen, which 

 not being sulphureous did not incommode those persons 

 even who were nearest to it. The thermometer had risen to 

 42 degrees. Twenty^four pounds of water, which were in 

 a copper vessel on the furnace, then began to boil. The 

 thermometer stood at the same degree for"l2 minutes, and 

 the water continued to boil for 20. When the ebullition 

 had ceased the thermometer fell to 26 degrees, and the 

 water was reduced to three pounds. The fossil was entirely 

 consumed in the course of an hour and a quarter, and left 

 225 grains of yellowish impalpable ashes in the form of 

 flakes. 



He then repeated the experiment under the same circum- 

 stances, and with oak charcoal. The latter kindled in twelve 

 minutes, and in four more the 24 pounds of water contained 

 in the copper boiler entered into ebullition. The thermo- 

 meter rose to 38 degrees, at which it maintained itself for 

 18 minutes, and when the ebullition ceased the thermome- 

 ter fell to 25 degrees. Almost the whole of the water was 

 evaporated, and the coal, being consumed in the course of 

 an hour and a half, left only 154 grains of ashes. 



By this experiment, calculating the sum total of the heat 

 respectively extricated during the combustion of the two 

 substances, tne author was able to remark, that the bitu- 

 minous wood produced 816 degrees of heal during an hour 

 and a quarter ; while oak charcoal, in an hour and a half, 

 produced only 784, 



He 



