FULGURITES, OR LIGHTNING-HOLES. 



533 



bly the most extensive find of fulgurites yet noted in this country. 

 The locality where they occurred is the top of a sand-hill some fifty 

 feet square. Several sets or pairs of tubes were found here, but a few 

 inches apart, together with several small, irregular masses of fused ma- 

 terial, the largest of which weighed several ounces. The largest tube 

 found was about three and a half inches in diameter, but was too frail 

 to remove. The accompanying plate shows the characteristic forms. 



Fig. 2. 



Fig. 3. 



* k 



Fig. 4. 



Fig. 1. 



Fulgurite TrBEs (natural size). (Reproduced from Proceeding of (he United States National 

 Museum, vol. ix, 1S86.) Fipr. 1, portion of tube, common form; Fig. 2, tube with bulb-like 

 enlargement; Fig:. 3, cross-section of tube, characteristic torm ; Fig. 4, holes fused by light- 

 ning in sheet-copper, and. resembling fulgurite tubes in outline.' 



One of these was traced into the sand for a distance of about seven 

 feet, and was found to increase in size slightly from above downward. 

 They were frequently branched, and often sent out small, nearly flat 

 horizontal branches or shoots, about one quarter of an inch wide, and 



