HYDROGRAPHlfcAL SURVEY. 201 



From this Table we may observe, that the great- 

 est increase of specific gravity, by pressure, in the 

 specimens of the different kinds of wood submitted 

 to experiment, was obtained by the fir ; the next 

 greatest by the ash ; the next by the ehn ; the next 

 by the oak ; the next by the teak ; the next by the 

 hickery ; and the least by the mahogany. The cork 

 gained still less than any of the pieces of wood. 

 The proportion of impregnation of the same kind 

 of wood, in specimens of different sizes and shapes, 

 is derived from the experiments made on the ash ; 

 and it is curious to observe, that the largest cube 

 of ash, No. 14. and the parallel opipedon of the 

 same, No. 10. received the greatest proportional in- 

 crease of weight ; while the smaller pieces received 

 less and less additional weight, per cubic inch, as 

 they decreased in size. Thus, No, 14. containing 

 about 4 solid inches of wood, gained 145 grains 2?67' 

 cubic inch ; No. 13. of about 3 solid inches, gain- 

 ed 143 grains j^;f?' cubic inch; No. 11. of 2 solid 

 inches, gained 137 grains per inch ; and the spe- 

 cimens of 1 inch, solid contents, gained from 127 

 to 135 grains. It is also a little curious, that the 

 specimens sent to the depth of 2058 feet, were 

 as much impregnated as those sent down above 

 ()000 feet. The cube of ash. No. 11. consisting of 

 2 solid inches of wood, gained 137 grains per inch, 

 at the depth of 6348 feet, while a similar specimen 

 gained 138 grains, at the inferior depth of 3708 

 feet. In the same way, a cube of 4 solid inches 

 gained 145 grains ^kt inch, at the extreme depth ; 

 and 144 grains per inch, at the depth of 4836 



