168 Dr. B. Seemaiin on the Mammoth-tree of Upper California. 



upon his filial shoulders/' Subsequent investigations, however, 

 have proved his assumption to be erroneous. The Sequoia under 

 consideration is evidently a fast-growing species, performing, 

 according to the careful observations made by J. Reed of Peter- 

 borough, its growth between 6 p.m. and 6 a.m., and retarding 

 and increasing in proportion to the warmth of the night. Plants 

 raised from the seeds brought to England towards the end of 

 1853, had already in 1857 attained 6 feet in height, thus having 

 grown in every year about 1^ foot; so that if they continue 

 growing at the same rate, it would require two hundred years to 

 produce a tree 300 feet high. But it is a well-known fact 

 that the growth does not proceed at such a uniform rate ; and 

 no process except that of counting the annual layers of the 

 trunk can be applied for the purpose of computing the age of 

 these trees. Asa Gray, in a paper on the age attained by the 

 largest known trees, has attempted to do this; unfortunately, 

 the section of the trunk exhibited at Philadelphia, and supplying 

 him with the principal data, was not that of the Sequoia Wel- 

 lingtonia, as he at the time believed, but that of the Sequoia 

 sempervirens*; and it is probably owing to this mistake that the 



* By carefully bearing in mind that the trunk exhibited at Philadelphia 

 was that of Sequoia sempervirens, and not that of S. Welling tonia, Gray's 

 article, weeded of all matter arising from the confusion of the two species, may 

 still be made to bear indirectly upon the questionable age of the Mammoth- 

 tree. This I have attempted to do in the following. Gray says : — " The 

 size of this tree is such as to give it a presumptive claim to rank amongst 

 the oldest of the present inhabitants of the earth, its length being (on the 



authority of the proprietor of the section) 322 feet This section was 



taken at the height of 25 feet from the groimd, and, according to the mea- 

 surement of my friend Thomas P. James, Esq., of Philadelphia, it is about 

 12| feet in diameter, including the bark. Mr. James, at my request, has 

 taken a careful measurement of the wood itself, excluding the bark. The 

 three diameters taken by him res])ectively measure 9 feet 6 inches, 10 feet 

 4 inches, and 10 feet lOi inches; the average diameter of the trunk, at 



the height of 25 feet from the ground, is a little over 10 feet .'3 inches 



The section of the trunk at Philadelphia has been hollowed out by fire and 

 other means to a shell of 3 or -4^ inches in thickness. Of this I have, 

 through the kindness of the proprietor and of Mr. James, a piece of the 

 wood, including nearly 3 inches of this section. What is now wanted, and 

 what, unfortunately, I do not possess, is a foot or two of the wood from 

 the central parts of the tree, — a desideratum which may doubtless be sup- 

 plied hereafter. The data at hand, however, will suffice for determining 

 an age which the tree cannot exceed, unless it be supposed to have grown 

 more slowly durmg the earlier xoths of its existence than during its later 

 years, which is directly contrary to the ascertained fact in respect to trees 

 in general. Now, the piece of wood in my hands exhibits an average of 

 forty-eight layers in an inch. The semidiameter of the trunk at the place 

 where it was taken is about 5 feet 2 inches. If the tree increased in dia- 

 meter at the same rate throughout, there would have been 2y7<> annual 

 layers, which, allowing twenty-four years for the tree to have attained the 

 height of 25 feet, would give it an age of 3000 years from the seed. This 



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