DR. ANGUS SMITH ON PEAT. 295 



starting at this point is, that the wood being half-age, the 

 age of maturity being generally 70 years, the amount of 

 wood or thinnings taken out and dried previous to 35 

 will, I believe, correspond to what would be taken out 

 from 35 to 70.) The number of trees planted at first 

 would be 5000 to the acre ; and at the age of 35 there would 

 not be above 500 to the acre, and at 70 not more than 

 150. I find, then, that an average tree in one of our fair- 

 growing woods, and, I should say, an average of the coun- 

 try, contains 644 lbs. weight or 7^ cubic feet of timber, 

 84 lbs. of brush or branches, and an equal quantity of 

 roots, in all 812 lbs., which, multipled by 500 trees, gives 

 406,000 lbs. of wood to an acre. 



"I presume a deduction of one fourth would be the 

 weight in the dry state. On looking at Brown's book on 

 Forestry, he says that at Castle Forbes he found Scots- 

 pine wood to weigh in the rough state, at 60 years old, from 



81 J to 83^ lbs. to the cubic foot It has long been 



found that wood between 35 and 60 years old is about the 

 same weight, and after that it gets lighter. I have found 

 spruce wood to weigh at 35 or 50 years 70 lbs. per cubic 

 foot, and at the age of 90 only 57 lbs. 



" Hay 1 ton to 3 tons to an acre. 



Oats I 8 *™ 2 * 20 I 4020 lbs." 



I seed 1600 J 



I scarcely know what data for weight to adopt. I in- 

 tended to take 33 lbs. for the dry wood; but Mr. Begg 

 insists on 50 at least for his district ; and after all it is not 

 of much importance for our case. Neither do I know the 

 shrinkage ; but it is evident that the weight of the wood 

 is great at Deeside, although it is not so great on the 

 heights. Karmarsch's table, quoted in the ( Handworter- 

 buch der Chemie/ gives the specific gravity of the Pinus 

 sylvestris green as 0*8 11 to 1*005 (* n ^ s l as t> although above 

 the weight of water, is not so high as Mr. Begg mentions) . 



