[2] 



and to learn whether the annual rings or growths of ea- U 

 year, commencing with the last year and comparing bii<t .. 

 ward, year with year and tree with tree, exhibited a cc- *^ 

 cidence in thickness or a coincidence in variation. Beft 

 proceeding further in the elaboration of this point I \\J' 

 state that lack of time prevented my making the diagrahvi 

 and that the following measurements of four trees of tl o 

 species 'known as Pinus ponder osa — or yellow pine — wt^'\' 

 made for me by Mr. A. L. Roache, who was then visit' r*.. 

 the region: 



No. 1. 

 No, 2. 

 No. 3. 

 No. 4. 



Inside of bark, 

 Inches. 



20% 

 27% 

 33% 

 24 



Average Annual G^owiH 

 inside of bark- 



.3796 

 .3666 

 .4187 

 .3333 



Mean annual growth, .3745 of an inch. 



The thickness of the bark, it will be seen, varies coi 

 erably. The differences in the diameters, as shown in 

 columns, "inside" and " outsidfe of bark " being thj 

 the bark'on the two sides of the tree, require therefoj 

 be divided by two, to give the true thickness, and 

 ^o. 1, two inches; Ko. 2, one and a half inches; ] 

 two and a quarter inc?ies; and No. 4, two and three- 

 ter inches. 



These trees stood in such a station or position, as tc 

 formity of conditions, i. <?., character of soil and surj 

 exposure, etc., as to furnish a fair basis for a calculati 

 the kind herein made. 



It will be observed, upon adding up the column of 

 rings, and also the column of largest diameters, and 

 dividing these totals by four to get the average, that i] 

 region where they grew, about seventy years were reqi 

 to make a yellow pine thirty inches, or two and a half 

 in diandeter. The mean thickness of the annual rim 



