z..:^ 



Eleventh Year. 

 Vol. XXII. No. 560. 



OCTOBEK 27, 1893. 



Single Copies, Ten Cents. 

 J3.50 Per Year, tn Advance. 



CONTEN TS 



The Visitors to One Oak Tree. Morris Gibbs.. 

 The Use of Tuberculin and Mallein tor the 



Diagnosis of Tuberculosis and Glanders in 



Animals. "Bios." 



Notes and News 



Mental Images. E. A. Kirkpatrick 



Immunity and Cure in the Infectious Diseases. 



Victor U. Vaughan 



Consciousness Under the Influence of Cannabis 



Indica. E. W. Scripture 



Letters to the Editor: 



Science in the Schools. — A Reply. W. H. 



Sherzer 



Book-Reviews 



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NEW METHOD OF PROTEGTIM BUILDINGS FROM LIGHTNING. 



SPARE THE ROD AND SPOIL THE HOUSE! 



Tjightning Hestroys. Shall it be Tour Mouse or a Found of Copper? 



PROTECTION FROM LIGHTNING. 

 What is the Problem ? 



In seeking a means of protection from Ughruing-diacharges, we have In view 

 two objects,— the one the prevention oC damage to buildings, and the ottier 

 the prevention of Injury to life. In order to destroy a building in wholf or In 

 part, It is necessary that work should be done; that Is, as physicists express 

 It, energy is required. Just before the lightuiug-dlscnarge takes place, the 

 energy capable of doing I he damage which we seek to prevent exists in the 

 column of air extending from the cloud to the earth in some form that makes 

 It capable of appearing as what we call electricity. We will therefore call it 

 electrical energy. What this electrical energy Is, it Is not necessary for us to 

 consider la this place ; but that it eslstn there can be no doubt, as it manifests 

 Itself In the destruction of buildings. The problem that we have to deal with, 

 therefore, is the conversion of this energy into some other form, and the ac- 

 complishment of this in such a way as shall result lu the least injury to prop- 

 erty and life. 



Why Have the Old Rods Failed? 



When lightning-rods were first proposed, the science of energetics was en- 

 tirely undeveloped ; that is to say, in the middle of the last century scientific 

 men had not come to recognize the tact that the different forms of energy — 

 heat, electricity, mechanical power, etc.— were convertible one Into the other, 

 and that each could produce Just so much of each of the other forms, and no 

 more. The doctrine of the conservation and correlation of energy was first 

 clearly worked out in the early part of this century. There were, however, 

 some facts known la regard to electricity a hundred and forty years ago; and 

 among these were the atrractiog power of points for an electric spark, and the 

 conducting power of metals. Lightning-rods were therefore introduced with 

 the idea that the electricity existing in the lightniug-dlscharge could be con- 

 veyed around the building which ic was proposed to protect, and that the 

 building would thus be saved. 



The question as to dissipation of the energy involved was entirely Ignored, 

 naturally; and from that time to this, lu sitite of the best endeavors of those 

 Interested, lightning-rods constructed in accordance with Franklin's principle 

 have not furnished satisfactory protection. The reason for Ihis is appar nt 

 when it is considered that the olectrlcal energy existing in the atm')sphere 

 before the discharge, or, more exactly, in the column of dielectric from the 

 cloud to the earth, above referred to, reaches l''s maximum valu- on the sur- 

 face of the conductors that chance to be within the column of dlel-ctric; so 

 that the greatest display of euorgy^wlllbtou the surface of the very lightning- 

 rods that were meant to protect, and damage results, as so ofieu pro"«is to be 

 the case. 



It will ho \mderstood, of course, that this display of ener2:y on the surface 

 of the eld lightuiug-rods is aided by their bnitjg more or i si Insulated from 

 the earth, but in any event the very existeuce of suc^ a mass of metnl as an 

 old lightning-rod can only tend to produce a disastrous dissipation of olectrlcal 

 energy upon its surface, — *' to draw the lightning," as It l.s bO commonly put. 



Is there a Better Means of Protection ? 



Having cleared our minds, therefore, of anv idea of conducting electricity, 

 and keeping clearly in view the fact that in providing protection a'galnst light- 

 ning we must furulsh some me'tns by which the electrical energy may be 

 harmlessly dissipated, the question arises, " Can an Improved form be given 

 to the rod so that It shall a. ii this dissipation 7 " 



As the electrical energy Involved manifests Itself on the surface of conduc- 

 tors, the improved rod should be metallic ; but. Instead of making a large rod, 

 suppose that we make It comparatively small in size, so tliat the t.jtal amount 

 of metal running from the top of the house to some point a little below the 

 foundations shall not exceed one pound. Suppose, agaiu, that wo iairoduco 

 numerous Insulating Joints in this rod. We shall then have a rod that experi- 

 ence shows will be readily destroyed — will be readily dissipated —when a 

 discharge takes place; ati I it will be evident, that, so far as the electrical en- 

 ergy is consumed lu doiug ihis, there will be the less to do other damage. 



The only point that remains to be proved as to ihb utility of such a rod Is to 

 show that the dlsslpaiiou o( such a conductor di>6s not ti-nd to injure oiher 

 bodies In its immediate vicinity. Ou this poiu! I caa ouly ssy that I have 

 found no case where such a conductor (tor Instance, a bell wire) has been dis- 

 sipated, even If resting against a plastered wall, where there has beeu any 

 material damage done to surrounding objects. 



Of course, it is readily understood that such an explosion cannot take place 

 In a confined spaco without the rupture of the walls {the wire cannot be 

 boarded over); but in every case that I have found rf corded this dissipation 

 takes place just as gunpowder burns when spread on a board. The olijects 

 against wtdch the conductor res's may be stained, but they are not shattered, 



I would therefore make clear this distinction between the action of electri- 

 cal energy when dissipated on the surface of a large conductor and when dis- 

 sipated on the surface of a comparatively small or easily dissipated conductor. 

 When dissipated on the surface of a large conductor, — a conductor so strong 

 as to resist the explosive effect,- damage results to objects around. When 

 dissipated on the surface of a small conductor, the conductor goes, but the 

 other objects around are saved 



A Typical Case of the Action of a Small Conductor. 



Franklin, in a letter to CoUlnsou read before the London Royal Society, 

 Deo. 18, 1TS5, describing the partial destruction by lightning of a church-tower 

 at Newbury, Mass., wrote, " Near the bell was fixed an iron hammer to strike 

 the hours ; and from the tall of the hammer a wire went down through a small 

 gimlet-hole In the floor that the bell stood upon, and through a second floor in 

 like manner; then horizontally under and near the plastered celling of Ihat 

 second floor, till it came near a plastered wall; then down by the side ol that 

 wall to a clock, which stood about twenty feet below the bell. The wire was 

 not bigger than a common kulttiug needle. The spire was split all to piece'' 

 by the lightning, and the parts flung in all directions over the square in Which 

 the church stood, so that nothing remained above the beU. The lljbtrirg 

 passed between the hammer and the clock in the above-mentioned wire 

 without hurting either of the flnors, or having any effect upon them (except 

 making the gimlet-holes, through which the wire passed, a little bigger), and 

 without hurting the plastered wall, or any part of the building, bo tar as the 

 aforesaid wire and ttie pendulura-wlre of the clock extended; which latter 

 wire was about the ihicbnesa of a go.ve-qu'll. From the end of the pendu- 

 Ittm, down quite to the ground, the bull iiu'^ was exceedingly rent and dam- 

 age 1. . . . No pirt of the aforementioned 1 mg, small wire, between the clock 

 and the ham "in-, could he round, except about two Inches that hung to the 

 tail «f fye hammer, aud about as much that was fastened to the clock ; the 

 rest being exploded, and its particles dissipated In smoke and air, as gun- 

 powder is by common fire, anu bad ouly left a black smutty track on the plas- 

 ter in?, three or four inches broad, darkest in the ralddlo, and fainter towaids 

 tb.e edges, sH along the celling, under which It passed, aud doivn the wall. ' 



One hundred feet of the Hodges Patent Lightning DIspeller (made under 

 patents of N. D. C. Hodges, Editor of Science) will be mailed, postpaid, to any 

 address, on receipt of Ave dollars ($5). 



Correspondence solicited. Agents wanted. 



AMERICAN LIUHTNINO PROTECTION CO., 



874r Broadway, New York Citv. 



