488 



THE POPULAR SCIEXCE MONTHLY. 



or did he write under the influence of divine 

 inspiration ? 



Rev. J. C, Mahin. 



Peru, Indiana, June 21, 1875. 



THE MECHANICAL POWEK OF LIGHTNING. 

 To the Editor of Hie Popular Science Monthly : 



In the afternoon of June 26, IS'/i, a 

 thunder-storm passed over the town of 

 Cummington, Hampshire County, Massa- 

 chusetts, duruig which an exhibition of the 

 mechanical power of lightning was dis- 

 played, which I believe is extremely rare, 

 at least in this latitude. 



A sugar-maple tree {Acer saccharinum), 

 thirteen feet in circumference four feet from 

 the ground, was struck, and split in several 

 places, apparently throughout its diameter, 

 from the ground to a height varying from 

 twelve to twenty feet. On reaching the 

 .earth, the main portion of the shaft 

 passed to a piece of wet ground several 

 rods distant, in its way ploughing a fur- 

 row from one to over three feet in depth, 

 tearing seven trees, the largest six inches 

 in diameter, from the ground, and throwing 

 them several feet from their former places, 

 A rock containing thirty-six cubic feet was 

 torn from its bed, and rests on the sur- 

 face, three feet from its original position. 

 In its course it passed under another maple, 

 two feet in diameter. The tree was not 

 thrown down, but the earth was thrown up 

 from beneath its roots, in places, to tlie 

 depth of three feet. This tree stood about 

 sixty feet from the one struck. It then 

 passed thirty or forty feet farther, through 

 earth so wet in some places that the trench 

 made by it filled with water. After making 



I a cut eiglit feet wide at the surface, and 

 ' three feet deep through a knoll, it divided, 

 and, alter passing a short distance farther, 

 struck at three points a half-inch lead 

 water-pipe, running at right angles with 

 its centre, filled with water at the time, 

 and covered with about two feet of wet 

 earth, which was thrown out, and the pipe 

 destroyed for a distance of 200 feet. No 

 trace of the pipe could be found in many 

 places, excepting scattered gray oxide of 

 lead. In its way from the tree to the pipe, 

 large masses of mica-slate rock were shat- 

 tered, and one observer saw large stones 

 which were thrown above the top cf the 

 surrounding trees. 



Nearly the whole distance traversed by 

 the lightning was woodland, and the soil 

 was firmly bound together by interlacing 

 roots ; many of these, large enough to resist 

 the power of the strongest yoke of oxen, 

 were snapped like pipe-stems, the fracture 

 being almost as smooth as if cut with a 

 saw. Lighter portions of the electricity 

 radiated in various directions from the 

 tree, turning up the earth like a plough, for 

 a distance of from 40 to 100 feet. The 

 tree was struck while the rain-cloud was 

 at least two or three miles distant. Many 

 people were out, making preparation for 

 the coming shower at the time, and the 

 bolt was seen by several persons as it 

 darted from the coming cloud. I visited 

 the place nearly a year after the event, but 

 all that I have described is yet visible. I 

 can only account for this tremendous force 

 by supposing that the water in the soil, con- 

 verted instantly to steam, produced these 

 results. Dewey A. Cobb. 



Pkovidbnce, R. I., Juiw, 18T5. 



EDITOR'S TABLE. 



RELATIVITY OF TRUTH. 



AMOXG the higher influences of 

 science to be realized in tlie fu- 

 ture, will be its inculcation of more cor- 

 rect views concerning the relation of 

 the human mind to truth. The etfect of 

 partisanship in politics and theology 

 the two great schools in which people are 

 chiefly educ<ited is to establish the idea 



that truth is something absolute, that 

 can be got once for all, and then can be 

 comfortably held and professed forever 

 afterward. There are only truth and 

 its opposite error sharply divided oft' to 

 choose from; and a "yes" or "no" is 

 demanded for all propositions. In some 

 things this is no doubt true; there is 

 only one side to the multiplication-table. 



