26 SYLVA FLOIUFERA. 



from the ground: narrow troughs of about 

 twenty inches long are fixed in the incisions, 

 to convey this liquid into receivers below. 

 The principal season for collecting this resin- 

 ous juice is from the end of May to Septem- 

 ber. As our larch-trees become aged, we 

 may fairly calculate on saving much money 

 to the country by using turpentine extracted 

 from our own woods. It is only after the 

 tree has attained the thickness of ten or 

 twelve inches in diameter, that it is thought 

 worth while to collect the turpentine ; and 

 from that time, during 40 or 50 years, if it 

 continue in vigorous growth, the tree will 

 continue to yield annually from seven to 

 eight pounds of turpentine. 



Martyn calculates that an English acre will 

 contain 682 trees, at the distance of eight 

 feet from each other. Suppose the annual 

 produce to be six pounds a tree, on an average, 

 and the price to be no more than two-pence 

 the pound, the value of the produce would be 

 31. 4s. 2d. the acre. 



1 1 was from old larch-trees that the ancients 

 gathered the agarick, so celebrated by their 

 medical writers ; but this fungous substance is 

 now fallen into total disuse as a medicine in 

 this country, though it is still used in northern 

 countries as an emetic in intermitting fevers. 



