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THE POPULAR SCIENCE MONTHLY. 



Passing by, for lack of space, the interesting accounts given by- 

 Darwin* and Fiedler f of fulgurites found at Maldonado, near the 

 mouth of the La Plata, in South America, and in a vineyard on the 

 right bank of the river Elbe, and simply noting the finding of similar 

 tubes at Northfield Farms, Massachusetts, in 1861, \ we will mention the 

 next recorded occurrence at Macclesfield, England, # which, like that of 

 Cumberland, is remarkable on account of the length of the tube found. 

 This is described as three fourths of an inch in diameter at its upper 

 end, and tapering gradually throughout its length to within three or 

 four feet of its lower end, where it assumed a slanting direction, and 

 then divided into several filaments or branches, and became dispersed 

 and obliterated in the soft, spongy soil. This fulgurite was traced to 

 a depth of twenty-two feet in a straight line, and gives us a good 

 illustration of the immense heat and power of penetration of an elec- 

 tric discharge. 



The occurrence described by Roemer,| of twenty-five sets of ful- 

 gurite tubes, within a space of one hundred by two hundred yards in 

 the great sand-flats of Starczynow in Poland, is, I believe, the most 

 remarkable on record. The sand in this case was a very pure quartz- 

 sand with a few pebbles of rolled flint (" Feuerstein "). 



The tubes were found with their upper ends exposed, owing to the 

 blowing away of the loose sand, and varied in size from the thickness 

 of one's arm to that of a wooden knitting-needle, while the thickness 

 of the tube- wall varied from one to two millimetres, rarely more. 



An article by the present writer A gives a detailed description of 

 fulgurites from Santa Rosa Island, Florida ; Sumter, South Carolina ; 

 and Union Grove, Illinois, now in the collections of the National 

 Museum. 



Those from Santa Rosa were formed by the lightning striking a 

 small pine-tree, and thence descending to the ground, where, at a dis- 

 tance of about forty feet from the trunk it formed a tube, which oc- 

 curred as a crooked, irregular line along the surface. This was nearly 

 pure glass, grayish in color, translucent, and very free from corruga- 

 tions, though in some cases completely collapsed. The small frag- 

 ments of the tube from Sumter, South Carolina, were found while 

 digging a well at a depth of twenty feet below the surface. The tube- 

 walls were very thick and strong, brownish and opaque. They lacked 

 the corrugations, but had, externally, rather the knotted appearance 

 compared by Giirabel to that of stag's horns. The great amount of 

 material received from Union Grove, Illinois, shows this to be proba- 



* " Voyage of II. M. S. Beagle." 



f "Comptes Rcndus," vol. xvii, 1843, p. 216. 



1 "American Journal of Science," vol. xxxi, p. 302. 



* " Geological Magazine." 1865. 



|| " Neues Jahrbuch fiir Mineralogie," etc., 1876. 



A Shortly to appear in " Proceedings of the National Museum," vol. ix, 1886. This 

 article gives also a very full bibliography of the subject. 



