Lightning Conductors in Ships. 167 



pieces, I ordered the sails to be taken in. We saw upon different 

 parts of the ship above thirty St Elmo's fires ; amongst the 

 rest there was one upon the top of the vane of the main-mast 

 more than a foot and a half in height ; I ordered one of the 

 sailors to take it down. When this man was on the top he 

 heard this fire; its noise resembled that of fired wet gunpowder. 

 I ordered him to lower the vane and come down, but scarcely 

 had he taken the vane from its place, when the fire fixed itself 

 upon the top of the main-mast, from which it was impossible to 

 remove it." 



24. Since, then, the conducting power of bodies differs only 

 in degree, and that the action by which they are assailed is the 

 result of a great natural agent quite independent of them, we 

 may expect to find all bodies liable to be assailed by lightning, 

 though the effects may be most appai'ent when the conducting 

 power is imperfect. Thus we find cases on record, of ships 

 struck by hghtning in which no metallic spindles were present, 

 or other iron work about the mast-head;* moreover, it is by 

 no means an uncommon circumstance to find trees and rocks 

 rent asunder by lightning, and to hear of men and quadrupeds, 

 even in a plain and open country, destroyed at the time of a 

 thunder-storm, when the electric matter strikes the earth's sur- 

 face. 



{To he continued.) 



On the Proximate Causes of certain Winds and Storms. By 

 Professor E. Mitchell, University of North CaroUna f. 



L HE four following propositions may be regarded as statements 

 of general facts, which have been sufficiently established by 

 numerous observations in various parts of the world. 



I. That part of the great oceans which lies between the 30th 

 parallel of latitude on both sides of the equator, is constantly 

 swept by a wind varying but a few points from the east. 



II. Between the latitudes of 30° and 60°, in both the nor- 

 thern and southern hemisphere, westerly winds predominate 



• See Philosophical Transactions, vols. xlix. and Ixix. damage done to the 

 sheer hulk at Plymouth, and on board the Atlas, East Indiaman. 

 f From Sillimau's American Journal of Science and Arts, vol. xix. 



