vo 



Eleventh Year. 

 Vol. XXII. No. 546. 



JULY 21, 1893. 



Single Copies, Ten Cents. 

 3.50 Per Yeah, in Advanob. 



Contents. 



The South Dakota Artesian Basin. W. S. 



Hall 



A Row OF Hieroglyphs, Casa No. 2, Palenque. 



H, T. Cresson 



The Osage River and Its Meanders. Arthur 



Winslow 



The Boom of the Prairie Chicken. T. A. 



Bereman 



A Silk-Spinning Cave Larva, H. Garman.... 



A New Orthography. J. I. D. Hinds 



Electrical Notes. R. A. F. 



A New Instance of Stream Capture. Hunter 

 L. Harris 



Insectivorous Plants of South Florida. G. 

 W. Webster 



Quantity and Quality of Milk. W. W. Cooke. 



Letters to the Editor. 



All Unusual Aurora. W. H. Howard 



The Aurora. M. A. Veeder 40 



Natural Selection at Fault. J. W. Slater... 41 i 



;l 



Beaver Creek Meteorite. Edwin E. Howell. 41 



Walker Prizes in Natural History. 



The Boston Society of Natural Hlfiitory 



offers a first prize of from $60 to $100 and a second 

 prize of a sum not exceeding $50 for the best me- 

 moirs, in English, on one of the following sub- 

 jects: 



1. The relations of inflorescence to cross-fertiliza. 

 tion illustrated by the plants of Eastern Massa, 

 chusetts. 



2. What depths of formerly ovnrlying rocks, now 

 removed by denudation, may be inferred from the 

 structure of various rocks in Eastern Massachu- 

 setts ? 



3. Experiments affording evidence for or against 

 the theory of evolution. 



Each memoir must be accompanied by a sealed 

 envelope enclosing the author's name and super- 

 scribed by a motto corresponding to one borna by 

 the manuscript, and must be handed to the Secre- 

 tary on or before April 1, 1894. 



Prizes will not be awarded unless the memoirs are 

 of adequate merit. 



Entered at the Post-Ofiflce of New York, N.Y., ( 

 Second-Class Mail Matter. 



SAMUEL HENSHAW, Secretary. 



I Boston, July 3, 1S93. 



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 Notes on Design of Small Dynamo, by G. Halliday, 

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The Batrachians and Reptiles of Indiana. 



A Work of 804 pages, with 3 plates of 12 figures. 

 Contaius full descriptions of nearly one hundred 

 species of Batrachians and Reptiles, together with 

 abundant notes on their habits. The identification 

 of the species made easy by means of analytical 

 tables. By O. P. Hay, Ph.D. Price, in paper cover, 

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Bowen-Merrill Book Co , Indi; 



apolis, Ind. 



PCDIUIAMIA -^ monthly magazine for the study 

 uCnmHIllH of the German language .and litera- 

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 Box 151. Manchester, N. H. 



NEW METHOD OF PROTECTING BUILDINGS FROM LIGHTNING. 

 SPARE THE ROD AND SPOIL THE HOUSE! 



Jjightning Destroys, Shall it be Your Souse or a Found of Copper? 



PROTECTION FROM LIGHTNING. 

 What is the Problem ? 



In seekiQg a means of protection from llghtniag-discharges, wo have in view 

 twoobjects,— the oue the prevention of damage to buildings, and the other 

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

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

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

 energy capable of doing the 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 in this place ; but that it exists there can be no doubt, as it manifests 

 itself In the destruction of buUdiugs. The problem that we have to deal with, 

 therefore, is the conversion of thld energy into some other form, aud the ac- 

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

 erty and life. 



Why Have the Old Rods Failed ? 



When lightoing-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 recogolze the fact that the different forms of energy — 

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

 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 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 those 

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

 have not furnished satisfactory protection. The reason for this i^ apparent 

 when it is considered that the electrical energy existing In the atmosphere 

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

 cloud to the earth, above referred to, reaches its maximum value on the sur- 

 face of the conductors that chance to be 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 often proves to be 

 the case. 



It will be understood, of course, that this display of energy on the surface 

 of the old lightning-rods Is aided by their being more or 1:*S3 Insulated from 

 the earth, but in any event the very existence of such a mass of metal as an 

 old llghtnlng-rod can only tend to produce a disastrous dissipation of electrical 

 energy upon its surface,— ''' to draw the lightning," as it is so commonly put. 



Is there a Better Means of Protection? 

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

 and keeping clearly in view the fact that in providing protection against light- 

 ning we must furnish some means 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'd In this dissipation ? " 



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

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

 suppose that we make it comparatively small in size, so that the t >tal amount 

 of metal running from the top of the house to .=Jome point a little below the 

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

 numerous insuUting joints in this rod. We shall then have a rod that experi- 

 ence shows will be readily destroyed — will be readily dissipated — wtieaa 

 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 damagy 



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 does not tr-nd to Injure other 

 bodies In irs immediate vicinity. On this poin: I cai only say 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 place just as gunpowder burns when spread on a board. The objects 

 agalEst W'llch the conductor res's may be stained, but they are not shattered, 



I wo'jld 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 CDuductor. 

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

 a^^ to resist the explosive efldcr, — damage results to objects around. When 

 dissipated on the surface of a small c:>uductor, 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 Collinson read before the London Royal Society, 

 Dec. 18, 1755, describing the partial destruction by lightning or a church-tower 

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

 the hours ; aud from the tall of the hammer a wire wont down through a small 

 gimlet-hole in the floor that the bell stood upon, aud through a second floor m 

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

 second floor, till it came near a p'astered wall ; then down by the side o' 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 pieces- 

 by the lightning, and the parts fluug lu all directions over the sqiare In which 

 the church stood, so that nothing remained above the bell. The lightricg 

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

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

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

 without hurting the plastered wall, or any part of the building, so far as the 

 aforesaid wire and the penduIum-wlre of the clock exteuJed ; which latter 

 wire was about the thickness of a goose-qudl. From the end of the pendu- 

 lum, down quite to the ground, the builllu? was exceedingly rent and dam- 

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

 aud the hammer, could be found, except about two inches that hung to the 

 tall of the hammer, and about as much that was fastened to the clock; the 

 rest being exploded, and ltd particles dissipated in smoke and air. as gun- 

 powder is by common fire, and had only left a black smutty track on the plas- 

 tering, three or four inches broad, darkest in the mlddl\ aud fainter towards 

 the edges, all along the ceiling, under whi^'h it pas-jed, and down the wall.'' 



One hundred feet of the Ho.lges Patent Lightning Dlspellar (made under 

 patents of N. D. C. Hodges, Editor of Science) will be mailed, po3:paid, to any 

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



Correspondeiice *tolicited. Agents wanted. 



AMERICAN LIGHTNING PROTECTION CO., 



874r Broad waj", New York Citv. 



