504 PHILOSOPHICAL TRANSACTIONS. [aNNO 1769. 



it would be, that mountains are produced by volcanos, and not volcanos by 

 mountains. He adds, Vesuvius is quiet at present, though very hot at top, 

 where there is a deposition of boiling sulphur. The lava that ran in the Fossa 

 Grande during the last eruption, and is at least 200 feet thick, is not yet cool ; 

 a stick put into its crevices takes fire immediately. On the sides of the crevices 

 are fine crystalline salts; as they are the pure salts, which exhale from the lava 

 that has no communication with the interior of the mountain, they may perhaps 

 indicate the composition of the lava. 



P'. On the Trees zvhich are supposed to be Indigenous in Great Britain. By the 

 Hon. Daines Barrington, F.R.S^ p. 23. 



Before entering into other particulars, Mr. B. lays down some general rules, 

 from which it may be decided, whether a tree is indigenous or not in any coun- 

 try. I. They must grow in large masses, and cover considerable tracts of ground; 

 nor must such woods end abruptly, by a sudden change to other trees, except 

 the situation and strata become totally different. 2. If the tree grows kindly in 

 copses, and shoots from the stool, it must for ever continue in such a wood, 

 unless grubbed up with the greatest care; nor is it then easily extirpated. 3. 

 The seed of such tree must ripen kindly: nature never plants but where a suc- 

 cession may be easily continued, and in the greatest profusion. Lastly, many 

 places in every country must receive their appellation from indigenous trees which 

 grow there ; as no circumstance is more striking, when a tract of ground is to 

 be described or distinguished : hence so many towns, villages, and farms are 

 named from the oak and ash, which are the most common trees of Great Britain. 

 When the instances of this are singular, it will prove directly the contrary. 



Having premised these general rules, by which it may be determined, whether 

 a tree has been planted by the hand of nature or not ; he begins by considering 

 the proofs which are commonly relied on, with regard to the Spanish, or sweet 

 chestnuts being indigenous in Great Britain. And, first, the very name of 

 Spanish seems most strongly to indicate the country from which it was originally 

 introduced here, a^jmuch as if a particular species of oak was known in Spain by 

 the name of the English oak. There may be some doubts perhaps whether this 

 tree is really a native of any part of Europe, as Pliny informs us, chestnuts were 

 brought from Sardis to Italy, and that they were improved in taste by Tiberius, 

 who took particular delight in cultivating them. Though so much has been said 

 of late, with regard to the excellence of this wood for building, Mr. B. cannot, 

 on inquiry, find that it is greatly prized for this purpose either in Spain, Italy, 

 or the south of France; but it is chiefly valued for the fruit, which forms a con- 

 siderable article of food for the inhabitants, as well as of exportation. Nor can 

 he hear that this tree is to be found in any considerable masses, till the traveller 

 is at least 200 miles to the south of Paris. With us the nuts by no means ripen 



