1819.] Scientific Intelligence. 235 



person might contrive two valves to prevent the mixture of the 

 gases from being driven back, and the passage of the flame, 

 which would, in my opinion, preclude all possibility of explosion.* 



H. B. Lf.eson. 



XL Larch Tree (Pinus Larix). 



The first larch trees ever seen in Scotland were sent to the 

 Duke of Athol at Dunkeld, in the year 1738, in two garden-pots. 

 They came from Switzerland, and were at first put into the 

 green-house. By degrees, it was discovered that they could 

 bear the winter in Scotland without injury. They were, there- 

 fore, planted in the Duke of Athol's park at Dunkeld, very near 

 his house. There they may be still seen, having grown in the 

 course of 81 years, which have elapsed since they were planted, 

 to the size of very large trees. Their circumference, about a 

 foot above the ground, is nearly 18 feet; and at the height of 

 eight feet, the circumference is nearly 14 feet. Thus in 81 years 

 they have produced as much wood as an oak would in the course 

 of several centuries. From these two parent trees have sprung 

 all the larches which abound so much in Scotland. 



The larch tree is now almost every where preferred to the 

 Scotch fir, which it has in a great measure superseded. It is a 

 much more beautiful tree ; it vegetates much more rapidly ; is 

 not so difficult to please in a soil ; and is at least as hardy, if, 

 not more so. The larch wood is not inferior to that of the fir, 

 and the bark is purchased by the tanner for about half the price 

 that he pays for oak-bark. Trials have been made of it for 

 ship-building, which have answered very well. At present, there 

 is a cutter building of it at Perth. 



XII. Wood in Scotland. 



The reproaches which Dr. Johnson in his Journey to the 

 Hebrides threw out against Scotland for its want of wood, 

 though perhaps a little exaggerated, were probably not very far 

 from the truth. That country, about a century before, had been 

 covered with old wood ; which, being considered by the proprie- 

 tors as of no value, was allowed to fall into decay without any 

 effort to preserve it ; while the introduction of sheep effectually 

 prevented the growth of young wood. Accordingly when the 

 old trees fell down from age, the country became quite bare. 

 But the reproaches of Dr. Johnson turned the attention of the 

 Scottish landlords to planting ; and in many parts of Scotland, 

 particularly in Perthshire, the defect of which Dr. Johnson com- 

 plained has been completely removed. The two greatest 

 planters of trees in that county, and perhaps in Scotland, are the 

 Duke of Athol and the Karl of Breadalbane. Each of these 

 noblemen, I have been informed, has planted at least 60,000,000 

 of trees. 



* Jiy the direction of the tubes, c c, the gnscs will cross one another, and thereby 

 be more completely mixed. 



