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Thtn> in a moderate way of growth, it will in-' 

 creafe one inch in circumference, being one quarter 

 of an inch girt yearly ; and as it is found by expe- 

 riment, that a fhaft of elm, thirty feet long, ex- 

 tends itfelf ten inches in four years, we may at leall 

 allow an inch a year for fuch extenfion in a fhaft 

 of oak of forty feet. It follows then, that at the. 

 end of twelve yeairs, when eighty-feven years of 

 age, the fhaft will be a foot longer, and having in- 

 creafed in girt three inches, it will meafure forty 

 feet in length by fifteen inches girt, equal to fixty- 

 four feet nine parts, the content whereof will be one 

 ton, twenty- four feet, nine parts. As the fhaft is 

 DOW increafed to more than twelve inches fquare at 

 the top, the four branches will begin to be mea- 

 furable at the bafe, 



' 'Inihe next twelve years, at 99 years of age, pro- 

 ceeding at the fame rate, it will have acquired 

 another foot additional length of fhaft, and three 

 inches increafed girt ; and will meafure as follows, 

 'viz. 42 feet by 18 inches girt, (equal to 94 feet 6 

 inches) the content whereof is 2 tons, 14 feet, 6 in. 

 and the four branches will be meafurable timber 

 to the length of two feet each, and their contents, 

 if feveri inches and a half girt, will be 2 tons, 17 

 ;feet, 7 inches. 



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