53 6 THE POPULAR SCIENCE MONTHLY. 



As already noted, he designated the fulgurites by the name of vit- 

 rified Osteocalla, or Ostecolla Masselsis, and proposed to utilize them for 

 medicinal purposes, placing them in the same category as deer-horns, 

 crab's eyes and corals, which at that time were considered as excellent 

 for all kinds of " fevers, virulent and febrile diseases." The finding of 

 the molten quartz directly in the track of the lightning at Aylesford, 

 England, as described in the " Philosophical Journal " noted, was ac- 

 cepted as proof positive of the electric origin of fulgurites by Fiedler 

 and most others. Nevertheless, Dr. Clark, of Cambridge, in one of his 

 public lectures in the year 1816, took occasion to deny this method of 

 origin regarding the fulgurites of Drigg, and contended that they were 

 but concretionary forms lined interiorly with a mineral resembling 

 hyalite or pearl sinter. Dr. Fiedler fully discusses all possible source 

 of origin, including the probability of their being incrustations on 

 roots, sinters, or other mineral products, or aggregates of ancient sea- 

 worms, and finally proves, apparently conclusively, their origin from 

 electric fusion, an origin concerning which there can at present be no 

 doubt. 



The cause of the frequent occurrence of fulgurite in sandy plains, 

 which seemingly present but little attractive force to the electric fluid, 

 has been frequently discussed. Fiedler ascribed it to the fact that at 

 certain depths below the surface there are little portions of water, and 

 the tubes are produced by the passage of the fluid from the surface to 

 these portions, where it becomes neutralized. Darwin, writing of the 

 Maldonado fulgurites, thinks it probable that in that particular in- 

 stance the flash divided into two or more branches before entering 

 the ground, rather than that they were formed by several distinct 

 discharges. To the present writer, the explanation suggested by 

 Roemer, regarding the extraordinary find at Starczynow, seems most 

 probable. Here it will be remembered that some twenty-five tubes 

 were found in a space one hundred by two hundred yards. Roemer 

 calls attention to the fact that these may have been formed at inter- 

 vals of even hundreds of years ; also to the equally important fact 

 that the lightning, although striking with the same frequency in less 

 exposed places, might fail to produce the tubes, owing to the char- 

 acter of the soil, or, if so produced, they would be obscured by leaves, 

 soil, etc., instead of having their upper ends exposed by the drifting 

 away of the sand. 



The deeply corrugated, or winged, and otherwise peculiar form of 

 the fulgurite tubes, has been a matter of some speculation. Darwin, 

 as already noted, considered it to be due to the pressure of the sand 

 acting while the tubes were still plastic — a view which has been in 

 many cases adopted by subsequent writers. Fiedler and Harting, on 

 the other hand, considered that the size and form of the tube, or, in 

 other words, the shape of the bore of the lightning, was largely depend- 

 ent upon the vapor engendered from the water in the sand at the time 



