132 Mr Law soil on the Trade -Winds at Barbadoes. 



cent rock and those of the fluid which had circulated. In the 

 latter case, the ores seem to have found their Avay simulta- 

 neously with the extraneous matters. The difference be- 

 tween the impregnations of the adjacent rock and the ore- 

 courses of the veins, may be explained, too, in that, in the 

 vein, a cause was at work which could only precipitate 

 certain ores, whilst others remained in solution, and only 

 came to be separated by longer contact with the components 

 of the rock, and by the power of elective affinity. However, 

 the watery solution may also have changed its nature in the 

 course of time. Nothing more strongly bespeaks the mutual 

 exchange than the above-mentioned substitution for felspar 

 or mica of blende and galena. 



In the same manner, we may conceive how, frequently at 

 the crossing of two veins of different formations, a group of 

 metallic minerals is found heaped together, which is not pe- 

 culiai*, as there grouped together, to either of the two veins 

 individually. Thus, for example, there ai'e frequently found 

 native silver, with sulphuret and antimonious sulphuret of 

 silver (silver-glance and red silver-ore), brittle silver- glance, 

 and earthy silver-glance, at the crossing of veins of tlie Ziig 

 and Halsbriicke formations, or at crossings of veins of the 

 Sauberg silver formation with the Ehrenfriedersdorf tin 

 formation ; or tin-ore is found in the silver veins of the 

 Annaberg formation, in fissures that branch to them. 

 (To be concluded in next Number.) 



Bemarks on the Trade-TFinds and other Currents in the Atmo- 

 sphere at Barbadoes ; with an attempt to develop the Causes 

 of Hurricanes in the TFest Indies. By Robert Lawson, 

 Esq., Assistant- Surgeon H.M. 47th Regiment. Communi- 

 cated by the Royal Scottish Society of Arts.* 



I. On the Trade-Winds. 

 1. The researches Avhich have been made on the nature of 

 the great storms in the West Indies, and of the Indian and 



* Abstract of a Paper read before the Society on 10th and 24th Feb- 

 ruary 1845. 



