Eleventh Year. 

 Vol. XXII. No. 557. 



OCTOBER 6, 1893. 



Single Copies, Ten Cents. 

 S3. 50 Per Year, in Advance. 



Contents. 



Current Notes on Chemistry.— III. Charles 



Piatt, Ph. D., P. C. S 



Notes and News 



Collection of Mexican Maguey Paintings. V. . 



Ring Pheasant. A. G. Prill, M. D 



The Bendigo Goldfield. T. S. Hall, M. A 



The Marine Tertiaries o£ Australia. T. S. Hall. 

 The Scientific Man on the Farm. Charles B. 



Cook 



The Eccentricities of a Pair of Robins. Olive 



Thome Miller 



Biological Notes from New Zealand.— II. Geo. 



M. Thomson 



The American Folk-Lore Society. R. V 



Some Remarks on the Kinetic Theory of Gases. 



S. Tolver Preston 



Discovery of Another Ancient Argillite Quarry 

 in the Delaware Valley. H. C. Mercer. .. 



Book Reviews 



Letters to the Editor. 



A Recapture from a River Pirate. Collier 



Cobb 



The Tin Ores of New South Wales and 

 South Dakota. Wm. P. Blake 



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NEW METHOD OF PROTECTIHG BUILDINGS FROM LIGHTNING. 

 SPARE THE ROD AND SPOIL THE HOUSE! 



Tjightning Destroys, Shall it be Your Souse or a JPound of Copper ? 



PROTECTION FROM LIGHTNING. 



What is the Problem ? 



IK seeking a means of protection from llgtituing-discharges, we have in view 

 two obiecta, — the one the prevention or damage to buildings, and the other 

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

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

 It, energy is required. Just before the lightning-discharge takes plaice, the 

 energy capable of doing the damage which we seek to prevent eslsta 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 In this place ; but that it exists 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 in the least injury to pi'op- 

 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 fact 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. Tiie doctrine of the conservation and correlation of energy was first 

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

 6ome facts known In regard to electricity a hundred and forty years ago; and 

 among these were the attracting 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 lightning-discharge could be con- 

 veyed around the building which it 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, in spite of the best endeavors of tb.:^e 

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

 have not furnished satisfactory protection. The reason for this U appar nt 

 when it Is considered that the electrical energy existing in the atmosphere 

 before the discharge, or, more exftclly, in the column of dielectric irom the 

 cloud to the earth, above referred to, reaches its maximum vain i' on the sur- 

 face of the conductors that chance to he within the column of dielectric; so 

 that the greatest display of energy will be on the surface of the very lightning- 

 rods that were meant to protect, and damage results, as so ofleu pro"<*s to be 

 the case. 



It will be understood, of course, that this display of energy on t'la surface 

 of the old lightning-rods is aided by their b>^liig more or i sh ins\i)u,ttr<l fiom 

 the earth, but In any event the very existence of suf^h a mass of met.nl a- an 

 old llghtnlng-rod can onlytend to produce a disastrous disslpillon of nlec'rioal 

 energy upon its surface,— '* to draw the lightning," as it Is to commonly p Jt. 



Is there a Better Means of Protection? 



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

 and keepingclearly Inview the fact that in providing protection agalusr^t Itght- 

 niuy we must furnish some me^-us by which the electrical eijer.:ry may he 

 harmlessly dissipated, the question arises. '* Can an Improved form be given 

 to the rod so that it shall a^ ta this dissipation ? " 



As the electrical energy involved manifests itself on the surface of conduc- 

 tors, the improved rod should be metallic; but, instead of maklog a large rod, 

 suppose that we make It comparatively small In size, so that the to;al amount 

 of metal running from the top of the house tos-ome poiuT a little below the 

 foundations shall not exceed one pound. Suppose, again, that we introduce 

 numerous Insulating joint? 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; ani it will be evident, that, so far as the electrical en- 

 ergy is consumed In doing this, there will be the less to do other d am ag?. 



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

 show that the dissipation of such a conductor due.s not tf nd to injure other 

 bodies in its Immediate vicinity. On this poinc I can only s«y that I have 

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

 sipated, even if resting against a plastered wall, where there has been any 

 material damage done to surrounding objects. 



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

 in a confined space without the rupture of the walls (the wire cannot be 

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

 takes placejust as gunpowder burns when spread on a board. The oV-Jt-cts 

 against which the conductor rests may be stained, but they are not shatieied, 



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

 cal energy when dissipated on the surface of alai'ge conductor and -Rhen 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 Coillnson read before the London Koyal Society, 

 Dec. 18, 1755, 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 fioor that the bell stood upon, and through a secoud fioor in 

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

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

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

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

 by the lightning, and the parts flung In all directions over the square in whi( h 

 the church stood, so that nothlug remained above the bell. The llghirire 

 passed between the hammer snd the clock in the above-men tionetJ w!re. 

 without hurting either of the floors, or havicg any effect upon them (exceiit 

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

 without hurting the plastered wall, or any pan of the building, so tar as the 

 aforesaid wire and the pendulum-wire of the clock extended ; which latter 

 wire was about the thickness of a goose-qu'll. From the end of the pendn- 

 lum, down quite to the ground, tha builiing was exceedingly reut and dhm- 

 aged. . . . No pirt of the alorementiouedljng, small wire, between the clock 

 and the hammer, oould be Pound, except about two Inches that hnng to the 

 tat'-^ftue hammer, and about as much that was fastened to the clock; ihu 

 rest being exploded, and It^ pHvtlclos dissipated in smoke and air, as gun- 

 powder is by common fire, aud had only left a black smutty tract on the pin-- 

 tft'-iug, three or four inches broad, darkest iu the mlddl", and fainter towaids 

 tb,.* edges, &tl along the ceiling, under which it passed, and do77u the wa'l. ' 



One hundred feet of the Hodges Patent Lightning Dlspeller (made uuder 

 patents of N. T). O. Hodges, Edi:or of Science) will be mailed, postpaid, to any 

 address, on rectslut oi five dollars ($5). 



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