VOL. LIII.] PHILOSOPHICAL TRANSACTIONS. 8 



The tree from which this bark was taken, is stiled by Ray, in his Synopsis, 

 salix alba vulgaris, the common white willow. Haec omnium nobis cognitarum 

 maxima est, et in satis crassam et proceram arborem adolescit. It is called in 

 these parts by the common people, the willow, and sometimes the Dutch willow ; 

 but if it be of a foreign extraction, it has been so long naturalized to this cli- 

 mate, that it thrives as well in it as if it was in its original soil. It is easily dis- 

 tinguished by the notable bitterness, and the free running of its bark, which 

 may be readily separated from it all the summer months, while the sap is up. 

 He took it from the shoots of 3 or 4 years growth, that sprung from pollard 

 trees, the diameters of which shoots, at their larger end, were from 1 to 4 or 

 5 inches: it is possible, and indeed not improbable, that this cortex, taken from 

 larger or older shoots, or from the trunk of the tree itself, may be stronger; but 

 he had not had time nor opportunities to make the experiments which ought to 

 be made upon it. The bark he had, was gathered in the northern parts of Ox- 

 fordshire, which are chiefly of dry and gravelly nature, affording few moist or 

 moory places for this tree to grow in ; and therefore, he suspected that it was not 

 so good here as in some other parts. Few vegetables are equal in every place; 

 all have their peculiar soils, where they arrive to a greater perfection than else- 

 where: the best and strongest mustard-seed is gathered in the county of Durham; 

 the finest safl^ron-flowers are produced in some particular spots of Essex and 

 Cambridgeshire; the best cyder-apples grow in Herefordshire, Devonshire and 

 the adjacent counties; the roots of valerian are esteemed most medicinal which 

 are dug up in Oxfordshire and Gloucestershire: and therefore why may not the 

 cortex salignus, or cortex anglicanus, have its favourite soil, where it may flourish 

 most, and attain to its highest perfection? It is very probable that it has; and 

 perhaps it may be in the fens of Lincolnshire, Cambridgeshire, Essex, Kent, or 

 some such like situations; and though the bark which grew in the county of Ox- 

 ford, may seem in some particular cases to be a little inferior to the quinquina, 

 yet in other places it may equal, if not exceed it. The powders made from this 

 bark are at first of a light brown, tinged with a dusky yellow ; and the longer 

 they are kept, the more they incline to a cinnamon or lateritious colour, which 

 he believed was the case with the Peruvian bark itnd powders. 



XXXIIl. Of an Earthquake in Siberia. In a Letter from Mons. fVeymarn to 

 Dr. Mounsey, Principal Physician of the Emperor of Russia, F. R.S. Dans- 

 lated from the French, p. 201. 



This earthquake, or rather these several earthquakes, happened in the months 

 of October, November, and December, 1761. They shook the buildings a little, 

 but did no damage. It is said that such earthquakes happen there frequently, 



B 1 



