I 6 TRANSACTIONS OF ROVAL SCOTTISH AKHOKICUI.TUKAL SOCIKTV. 



according to the cliarcoal they produce, the heap requires constant 

 attention day and night, and in all weathers. 



It is under totally different conditions that wood must be 

 carbonised if the gaseous products have to be recovered, and for 

 this purpose plant which will let no gas escape to the air is 

 necessary. Originally, the plan was to replace the mud and 

 clay by bricks and mortar, but this was soon found to be 

 impracticable, both as regards saving the gas and preventing 

 the access of air during the cooling process. There are still some 

 of these in use, principally for the manufacture of archangel 

 tar, the price of which is such that, coupled with cheap wood 

 and cheap labour, the losses can be ignored. The bulk of the 

 wood is now carbonised in cast or malleable iron cylinders, the 

 size of which varies from 3 ft. dia. to 8 ft. Each size has its 

 devotees and advantages and disadvantages, from the point of 

 view of time for each operation, yield of products and cost of 

 handling. 



[The suitability of charcoal for insulating purposes is dealt with 

 in the remainder of the paper, which includes many valuable 

 tables of interesting statistics. I 



3. Dupplin Castle Estates, Perthshire. 



By W. Daw SON. 



The Dupplin Castle Estates, the property of Sir John A. 

 Dewar, Bart., contain an area of about 2240 acres of wood- 

 lands in addition to about 120 acres of park or policy woods. 

 The woods had for long been neglected, and it is only three 

 years ago that a beginning was made with the present scheme 

 of management. The bulk of the woods had been planted 

 between 1780 and 1820, on ground which was once probably 

 moorland with marshy patches in parts. Some of the areas 

 had been agricultural land, though these areas had only formed 

 a very small part of the whole. Little planting had taken 

 place, from the end of the period mentioned till the present 

 scheme began, although there had been considerable activity 

 in the way of removing more or less ripe timber, by bare 

 clearing some areas and by over-thinning the rest. The conse- 

 quence is that the age-classes are now not well balanced. 

 There is too big an area of old timber in the form of under- 

 stocked woods; there is a large area unstocked ; and the areas 



