'134 PROCESS OF DEVELOPEMENT. CHAP. IV. 



hours it was found that the winter felled wood had 

 communicated a much deeper tinge to the water, 

 and raised its specific gravity to T002, the specific 

 gravity of the other being only 1-001. Whence 

 Mr. Knight concludes that the cause of the su- 

 perior quality of winter felled timber, and of the 

 conversion of the alburnum into wood, is attribu- 

 table to the matter deposited in the alburnum 

 during the preceding summer, and partially, 

 though not totally, carried off in the succeeding 

 spring.* 



Throws But after all this parade of experiment, it must 

 light on still be confessed that there is but little elucidation 

 ject. 8U thrown on the subject. For the truth of the facts 

 may be admitted, and yet the legitimacy of the 

 ultimate conclusion deduced from them may be 

 denied. It may be true that an extraordinary 

 quantity of proper juice is deposited in the al- 

 burnum in the course of the summer, which is 

 again partly carried off in the succeeding spring ; 

 and this will no doubt account for its superior 

 quality in the intervening winter. But how is it 

 to account for its final conversion into wood, a 

 change that is effected only by slow degrees, the 

 layer becoming every year more and more indu- 

 rated till it acquires in >the end its last degree of 

 solidity. For if the matter deposited in the sum- 

 mer is almost wholly carried off again in the suc- 

 ceeding spring, no progress has been made in the 

 * Phil. Tram. 1805. 



