438 Inquiries relative to the Structure of Wood. 



Ten grammes (154.5 grains) of those shavings, laid 

 on a china plate, were placed in a large stove made of 

 sheet-iron, and there exposed to a regular heat of about 

 245 F. for two hours, in the course of which time they 

 were frequently taken out and weighed in order to observe 

 the progress of their desiccation. When they ceased to 

 lose weight, the operation was stopped ; when perfectly 

 dried, their weight was 8.121 grammes. 



By previous trials with my apparatus, I had learned 

 that if the stove was too much heated the shavings 

 became discoloured, which is always indicated by the 

 emission of a particular odour, very readily to be per- 

 ceived ; but, by a careful regulation of the fire, this 

 accident may be avoided and the shavings be thoroughly 

 dried without injury, or even subjecting them to any 

 sensible alteration. 



I concluded that they had not undergone any change, 

 because, upon again exposing them to the atmosphere, 

 they regained the same weight which they had, under 

 similar circumstances, prior to their being dried in the 

 stove. 



Being thus 'possessed of the weight of my shavings, 

 as well under exposure to the air as in a dried state, 

 which latter I could not but look upon as being perfect, 

 it only remained to ascertain their weight in water when 

 all their vessels and pores were completely filled with 

 that liquid, to enable me to determine the specific grav- 

 ity of the solid parts of this wood, which was accom- 

 plished without difficulty by the following process : 



A cylindrical copper vessel, 10 inches in diameter and 

 as many deep, was filled with water from the Seine, 

 previously well filtered, and, being set upon a common 

 chafing-dish, was made to boil for some time, to expel 



