ME LIBRA&Y. 105 



flowing into the receiver, and the resiniferous vessels of 

 the tree become obstructed, the flow of the liquid is 

 arrested. To meet this it is necessary to change the 

 receivers every three days. When the wind is north-west 

 and west the air is cooled, and the turpentine flows till 

 the fourth day without any necessity to change the 

 receivers. 



' It has also to be stated, that when the incision penetrates 

 the sixth ring of the alburnum, there are thence obtained 

 only slight indications of turpentine ; that from the second 

 and third layers are obtained the largest quantities ; that 

 from the first and fourth there flows less, and still less 

 from the fifth. Amongst the trees chosen for observation 

 those from 35 to 45 years of age yielded proportionately 

 the greatest quantity of turpentine; and of these those 

 which were growing with greatest vigour and luxuriance. 



'The collecting of resin was continued till the 15th of 

 October, giving seven months of a resin harvest, or, as it is 

 designated, resination. Collected conveniently in a 

 receptacle prepared for the purpose, the whole quantity 

 measured 7335 litres, which was equivalent to about 1*2 

 litre per tree. From this, when manipulated in manner 

 and form to be afterwards detailed, there were obtained 368 

 litres, or 32 arrobas the arroba is a weight of 25 

 pounds of boras, or earth, impure resin, mixed with small 

 fragments of chips, bark, &c., or 5 per cent of the material 

 extracted and measured ; 5369 litres, or 467 arrobas, of 

 colofonia or resin, amounting to 78 percent; and 1471 

 litres, or 128 arrobas, of spirits or essence of turpentine, 

 equivalent to 20 per cent. ; and 147 litres, or 12 arrobas, 

 of water and other matters were lost by evaporation. 



' To determine the expense, and returns of the resination 

 of these 5000 trees, it is only necessary to state the value 

 of the products at the fabrique or manufactory on the 

 pinery of Villanueva : 467 arrobas of colofonia at 11 reals* = 

 5137 reals ; 128 arrobas of aquarras, or spirits of turpen- 



* The real is equal to 2d. 



