50 



Lightning Rods. — Philosophical Facts. 



Vol. VI. 



For the Farmers' Cabinet. 

 Lightning Rods. 



Will the erection of lifjhtninfif rods insure 

 pcrft'ct security, and is it certain that the 

 electric fluid will always pass down a rod in 

 pref>rence to making its way in another di- 

 rection 1 



On the 1st July last, during a thunder- 

 Btorti), the electric fluid struck the chimney 

 of a sugar-house in Race street, Philadelphia, 

 throwing a large portion of the bricks into 

 the street: the effects of the stroke were 

 Bensil)ly felt in the neighbonrhoo<], many peo- 

 ple were prostrated, and one man never re- 

 covered from the shock, dying in consequence 

 the next day. On repairing to the spot, it 

 was found that a conducting rod, to appear- 

 ance in perfect order, and leading far above 

 the highest point of the building at the gable- 

 end, and much higher than the chimney that 

 had been demolished, had not served its pur- 

 pose, although, by accurate measurement it 

 was found to be situated within fifteen feet 

 of the chimney. 



"During a thunder-storm on Saturday the 

 21st of August, a flash of lightning descended 

 from a cloud and struck the barn of Mr. S. 

 Baab, near Pricetown, Pa., in which four 

 men were standing, who escaped without ma- 

 terial injury, after being knocked down and 

 somewhat stunned. A conductor is attached 

 to the barn, but it appeared that the lightning 

 had descended dio<ronally, instead of passing 

 down the rod from the top, and struck the rod 

 about a foot from the ground, from which it 

 glanced off, and passimr throufrh a stone wall 

 from 12 to 16 inches thick, entered the wall 

 on the other side of the wagon-shed, where it 

 was spent, within a foot of those who were in 

 the barn at the time." 



The latter case reminds me of the account 

 furnished by Mr. N. J. Sharpless, of Down- 

 mgfown, page 10.") of the Cabinet, vol. 5, in 

 which it is said, one portion of the lightning 

 left the rod at the surface of the ground and 

 passed throiieh a wall, perforating several 

 holes, and killing two cows, which lay 25 feet 

 distant and in opposite directions. Now, pos- 

 sibly, in this case, the lightning never passed 

 down the rod at all, but stntck it diairnnaUy, 

 as above-mentioned — not fulfilling' its pur- 

 pose in the regular manner, bv drawinsr the 

 electric fluid from the over-cha'rged cloud and 

 depositing it harmlessly in the ncfratively- 

 charnred ground ; and certainly not'without 

 danger and injury to the building, or the ani- 

 mals lying 2.3 foet distant, 



Th.'re is a remarkable case of destruction 

 by iiirhtnmg recorded in the Knajish Philo- 

 sophical Transactions. A broad-wheel wagon, 

 while ascending a hill during a thunder-storm,' 

 was struck, and one or more of the horses, 



with, I believe, the driver, were killed; on a 

 very minute examination, it was discovered 

 that the electric fluid never descended from 

 the cloud at all, but issued from the earth, 

 immediately in contact with one of the wheels 

 in its passage, leaving a round hole immedi- 

 ately under it, as though it had been forced 

 up by the pressure of the wheel. 



A friend informs me, during a late visit to 

 Mr. Isaac Newton, Delaware county. Pa., he 

 could not but remark the very exposed situa- 

 tion of his barn, which has, however, never 

 yet been furnished with a conducting rod ; 

 but hitherto has escaped in a remarkable 

 manner the stroke of the electric fluid. It 

 stands very high, and has several very lofty 

 Lombardy Poplar trees in its immediate vi- 

 cinity, one of which, within about 50 feet of 

 the barn, was struck and destroyed some time 

 since ; a sow and pigs which were lying at its 

 foot at the time, sharing the same fate. An- 

 other tree, about 80 yards from the barn, and 

 in nearly a direct line, had since been struck 

 and destroyed, while during a late storm the 

 electric fluid had struck two other trees in 

 the vicinity, one in advance and another in 

 the rear of his premises, the top of one of 

 them being taken off and carried a considera- 

 ble distance, the barn still standing unscathed, 

 amidst all this "war of elements." Now, 

 need it be considered necessary to erect a 

 conducting rod to a building which has hith- 

 erto escaped injury with the lightning play- 

 ing all around it, while so many instances 

 have occurred where buildings carefully 

 guarded have suffered ] 



Is the idea new to your readers, that the 

 swallows always leave a barn before it is 

 struck by lightning, or are they aware, that 

 such a notion prevails in many parts of the 

 country, and is implicitly relied upon as a 

 facti My friend remarked that the barn of 

 Mr. Newton was thickly peopled with these 

 useful and inoffensive little creatures. 



Subscribes. 



August 25, 1841. 



Interesting Philosophical Facts. 



Sound travels at the rate of 1142 feet per 

 second in air, 4960 feet in water, 11,090 in 

 cast iron, 17,000 in steel, 18,000 in glass, and 

 from 4636 to 17,000 in wood. 



Mercury freezes at 38 degrees below 0, 

 Fahrenheit, and becomes a solid mass, malle- 

 able under tiie hammer. 



The greatest height at which visible clouds 

 ever exist, does not exceed ten miles. 



Air is about 816 times lighter than water. 



The pressure of the atmosphere upon every 

 square foot of the earth, amounts to 2160 lbs. 

 An ordinary sized man, supposing his surface 

 to be 14 s(iuare feet, sustains the enormous 

 pressure of 30,240 pounda 



