89.SINGLE P^B-oketokofApa · 2005-05-30 · menhadnotcometo recognizethefact that the different...

3
As the electrical energy involved manifests itself on the surface of conduc- tors, the improved rod should be metallic; but, iustead of making a large rod, suppose that we make it comparattvely small in size, so that thae t tal armount of metal runnleag from ths3 top of the house to some poinlt a little below the foundations sh-ill not exceed one pound. Suppose, again, that we iatrodace nurmerous insulating joint-3 in this rod. We shall then have a rod that experi- ence shows will be readily destroyed-will be readily dissipated -whea a discharge takes place; and it will be evident, thaat, so far as thle electrical en- ergy is consumed in doing this, there will be the less to do othaer damag i. The only point that remains to be proved as to the utility of such a rod is to show that thLe dtssipationl of such a conductor does not tend to inj ara other bodies in its immediate vicinity. On this poin-, I caa only say tthat I have found no case where such a conductor (for Instanlce, a bell wire) has been dis- sipated, even if restlug against a plastered wall, where there has been any material damage done to surrounding objects. Of couirse, it is readily understood that sach an expliosion canuot take place in a confined space wtthout the rupture of the walls (the wire cannot be boarded over); but in every case that I have found recorded this dtssipation takes place j ust as gunpowder burns when spread on a board. The objects agalinst wi,ich the conduutor rests may be stained, but they are not shattered, I wouzld th'erefore make clear this distinction between the action of el-ctri- cal energy when dissipated on the surface of a large conductor and when dis- sipated on the surface of a coinparatively small or easily dis3sipated canductor. When dissipated on the surface of a large conductor, -a conductor so strong as to resist the explostve effaect,-damage results to objects around. When dtseipated on the surface of a sm ill c -)d actor, the concductor goes, biit the other objects around are saved A Typical Case of the Action of a Small Conductor. FRranklin, ina letter to Collinson read before the London Royal Society, Dec. 18, 1755, describing the partial destruction by lightuinlg of a church-tower at Newbury, Maess, wrote, "1 Near the bell was fixed an iron hammer to strike the hours; and from the tall of the hammer a wire went down thirough a small gimlet-hole in the floor that the bell stood upon, and thirough a second floor In like manner; then horizontally under and Dear tthe plastered ceilinlg of that second floor, till. it came near a p astered wall; then down by the side of 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 pieces, by the lightning, and the, parts flung in all (lirections over the sq iare in whiLh the church stood, so that nothing remained above the bell. Trhe ligbtriDg passed between the hammner and the clock in thae above-mentioned wtre, without hurting either ot the fl-)ors, or having anly effect upon them (exrcept making the gimlet-holes, through whlch the wire passed, a littl 3 bigger), and without hurting the plastered wall, or any part of the building, so far as the aforesaid wire and the pendiilum-wire of the clock extended;* which latter wire was about the thickness of a goose-qu!11. From the end of the pendu- lum, down quite to the ground, the buill-ina was excceedingly reult and.dam- aged... No pe,rt of the aforementioned Ifong, small wire, between the clock and the hammer, could be found, ex;cept 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, aud it-3 particles dissipated in smoke and air, as gun- powder is by common fire, aud had only left a black smutty track on the plas- tering, three or four Inches broad), darkest in the middls3, and fatnter towards the edges, all along the ceiling, under which it passed, and down the wall." One hundred feet of the Hodges Patent Lightning Dlspeller (made under -patents of N. D. C. Hlodges, Editor of Science) wIll be mailed, postpaid, to any address, on receipt of flve dollars (S5). Correspondence solicited. Agents wanted. AMKERICAN LIGHR1'NINGE PROTEC8TION CoO., 874 B3roadway, New York Citv. ELEVENTH YEAR. JULY 1 89.SINGLE COPIES, TEN CENTS. VOL. XXII. NO. 546. J 1, 89._$3.50 PER YEAR, IX ADVANCR. C ON TE N TS. Walker Prizes in Natural His to _j Pema' P^B-oketokofApa I bets, _ eng~~~~~~~~~~~~~~ravers, stone-cutters and 'THE SOUTH DAKOTA ARTE5SIAN BASIN. W. S. Hfowar C r s PracticaYl LEeltetring' AI HIall . .... ....... .... ... 29 The B oston Soe.iety of N atIural H {story Universul Ha n y_ Every-day Electrical MSat- A ROW OF HIEROGSLYPHS, CASA NO. .2, PALENQUE. offers a tlrst prize of from $60 to $100 and a secoind Iters, 135 pp., full ilisrted, 12mo, cloth, 75 cts. TEBO.iG N IT. Creso ......... ........ 30 |prize of a sum not exceeding $50 for the best me- Notes on Design of Sal Dynamo, by G. Halliday, Wisow ..................31 moir.3 in English, on one of the following sub- $1. The Phonograpk and EIow to Construct It b THE Booms OF THIIE PRAIRIE CHICKSEN. T. A. |jects: W. Gillett, 87 p., 12 fldin plates, 12mno, eloth, U. ABIKSINN Ae LRA .Greman ..... 33..... 1. The relations of inflorescence to cross-fertiliza- St., New York. Illustrated and descriptive cata. A SIK SPNNIG C:VE ARVA H. armn... 33tion illustrated by the plants of Eastern Massa_'! logues, 10 cts. A NEW ORTHOGRAPHY. J. D. Hinds ..................... 34 chusetts. I ELECTRICAL NOTES. R. A. F ........... ......... 35 2. What depths of formerly overlying rocks, now The Batrachians and Reptiles of Indiana. A NEW INSTANCE OF STREAM CAPTURE. Hunter removed by denudation, may be inferred from the l. Harris ......... ............. 36, structure of various rocks in Eastern Massachu- INSECTIVOROUS PLANTS OF 'S'OU'TH FLORIDA. G. Isetts ? A Work of 204 pages, with 3 plates of 12 figures. W. Webster...... ...... .... .. 37 Contains full descriptions of nearly one hundred -QUANTITY.AND QUALITY OF MILK. W. W. Cooke. 38 3. Exrperiments affording evidence for or against !species of Batrachiaus and Reptiles, together with LETTERS TO THEIE EDITOR. | h hoyo vlto.Iof the species made easy by means of analytical A. Unusual Aurora. W. H. Howard .................... 39 Each memoir must be accompanied by a sealed tables. Bz O. P. Hay, Ph.D. Price, in paper cover, Light-Shunners and Light-Seekers. J. W. |envelope enclosing the author's name and super- postpaid, V;100. Sflater................. ................... 39 scribed by a motto- correspoinding to one borna by Bowen-Merrill Book Co , Indianapolis, Ind. The Aurora. M. A. Veeder ...... ................. ..... 40 ithe manuscript, and must be handed to the Secre- Natural Selection at Fault. J. W. Slater. .. 41: tary on or before April 1, 1894. CDU 1A monthly magazine for the study The Habitat and the Diet of the Lepidoptera. iPrizes will not be awarded unless the memoirs are GERMANrI A of the German language and litera- J. W. Slater. ....... ............ ..... 41 of adequate merit ......... ture. is highly recommended by college professors Beaver Creek Meteorite. Edwin E. Howell. Al .d the pruess as "te mbfestefftortnytet matdheito assist Enterd at he Pot-Offce ofNew Yrk, NY., SAMUEL HENSHAW, Secretary. y eUaraiEtcomplletBeaGnId inEteresctinng coururnshe in verma Entered at the Post-Omce of New Yorlr, N.Y., M |~~ grammar. $2 a year. Single copies 20 cents. P. O. Second-CMlass Mail Matter. Boston, July 3, 1893. Boxs 151, Manchester, N. H. NEW METHOD OF PROTECTING BUILDINGS FRON LIGHTNING. SPARE THE ROD AND SPOIL THE HOUSE! lZightning Destroys. Shall it be Your House or a Pound of Copper? PROI'ECTION FROM LIGHTNING. What is the Problem ? IN seeking a mieans of protection from lightning-discharges, we have in view two objects,- the one the prevention of damage to butidings, anld the other the prevention of injury tolife. In order to destroy abulldijig illwhole orjln part, It is necessary that work should be done;* that is, as physicists express it, energy is reqi-iired. Just before the lightning-dischiarge takes place, the energy capable of doing the damage which we seek to prevent exrigts in the column of air extenlding 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 witbh therefore, is the conversion of this energy into some other form, aud the ae- ,complishment of this in such a way as sihall result in the least injuary to prop- ery ndlie. 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 iscientific men had not come to recognize the fact that the d ifferent forms of onergy - heat, electricity, mechanical power, etc.- were convertible one Into the other, and that each could produace just so much of each of the other forms, and no more. The doctrtne ot 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 attractinig power of points for an electric spark, and the -conducting power of metals. Lightning-rods were therefore introduced with the idea that the electricity exristing in the lightning-discharge could be con- veyed around the<1building 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 is apparent when it is considered that the electrical energy existing in the atmosphere before the discharge, or, more exactly,jin 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 tbhe 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 surfaee of the old lightning-rods is aided by their being more or I zss insulated from the earth, but in any event the very existence of such a mass of metal as an old lightning-rod C8E1 only tend to produce a disastrous dissipation of electrical energy upon Its surface,-"' to draw the ligbtning," as it is socommonly put. Is, there a Better Means of Protection? HIaving cleared our minds, therefore, of any idea of conducting electrtelty, and keeping clearly in view the fact that in providlug protection against light- ulng we must furnish some means by which the electrical energy may be harmlessly dissipated, the question arises, "1Can an Improved form be given to the rod so that it shall aid In this dlssipation ?"

Transcript of 89.SINGLE P^B-oketokofApa · 2005-05-30 · menhadnotcometo recognizethefact that the different...

Page 1: 89.SINGLE P^B-oketokofApa · 2005-05-30 · menhadnotcometo recognizethefact that the different formsof onergy-heat, electricity, mechanicalpower,etc.-wereconvertible one Into theother,

As the electrical energy involved manifests itself on the surface of conduc-tors, the improved rod should be metallic; but, iustead of making a large rod,suppose that we make it comparattvely small in size, so that thae t tal armountof metal runnleag from ths3 top of the house tosome poinlt a little below thefoundations sh-ill not exceed one pound. Suppose, again, that we iatrodacenurmerous insulating joint-3 in this rod. We shall then have a rod that experi-ence shows will be readily destroyed-will be readily dissipated-whea adischarge takes place; and it will be evident, thaat, so far as thle electrical en-ergy is consumed in doing this, there will be the less to do othaer damag i.The only point that remains to be proved as to the utility of such a rod is toshow that thLe dtssipationl of such a conductor does not tend to inj ara otherbodies in its immediate vicinity. On this poin-, I caa only say tthat I havefound no case where such a conductor (for Instanlce, a bell wire) has been dis-sipated, even if restlug against a plastered wall, where there has been anymaterial damage done to surrounding objects.Of couirse, it is readily understood that sach an expliosion canuot take placein a confined space wtthout the rupture of the walls (the wire cannot beboarded over); but in every case that I have found recorded this dtssipationtakes place j ust as gunpowder burns when spread on a board. The objectsagalinst wi,ich the conduutor rests may be stained, but they are not shattered,I wouzld th'erefore make clear this distinction between the action of el-ctri-cal energy when dissipated on the surface of a large conductor and when dis-sipated on the surface of a coinparatively small or easily dis3sipated canductor.When dissipated on the surface of a large conductor,-a conductor so strongas to resist the explostve effaect,-damage results to objects around. Whendtseipated on the surface of a sm ill c -)d actor, the concductor goes, biit theother objects around are saved

A Typical Case of the Action of a Small Conductor.FRranklin, ina letter to Collinson read before the London Royal Society,Dec. 18, 1755, describing the partial destruction by lightuinlg of a church-towerat Newbury, Maess, wrote, "1 Near the bell was fixed an iron hammer to strikethe hours; and from the tall of the hammer a wire went down thirough a smallgimlet-hole in the floor that the bell stood upon, and thirough a second floor Inlike manner; then horizontally under and Dear tthe plastered ceilinlg of thatsecond floor, till. it came near a p astered wall; then down by the side of thatwall to aclock, which stood about twenty feet below the bell. The wire wasnot bigger than a common knitting needle. The spire was split all to pieces,by the lightning, and the, parts flung in all (lirections over the sq iare in whiLhthe church stood, so that nothing remained above the bell. Trhe ligbtriDgpassed between the hammner and the clock in thae above-mentioned wtre,without hurting either ot the fl-)ors, or having anly effect upon them (exrceptmaking the gimlet-holes, through whlch the wire passed, a littl 3 bigger), andwithout hurting the plastered wall, or any part of the building, so far as theaforesaidwire and the pendiilum-wire of the clock extended;* which latterwire was about the thickness of a goose-qu!11. From the end of the pendu-lum, downquite to the ground, the buill-ina was excceedingly reult and.dam-aged... No pe,rt of the aforementioned Ifong, small wire, between the clockand the hammer, could be found, ex;cept about two inches that hung to thetall of the hammer, and about as much that was fastened to the clock;* therest being exploded, aud it-3 particles dissipated in smoke and air, as gun-powder is by common fire, aud had only left a black smutty track on the plas-tering, three or four Inches broad), darkest in the middls3, and fatnter towardsthe edges, all along the ceiling, under which it passed, and down the wall."One hundred feet of the Hodges Patent Lightning Dlspeller (made under-patents of N. D. C. Hlodges, Editor of Science) wIll be mailed, postpaid, to anyaddress, on receipt of flve dollars (S5).

Correspondence solicited. Agents wanted.

AMKERICAN LIGHR1'NINGE PROTEC8TION CoO.,874 B3roadway, New York Citv.

ELEVENTH YEAR. JULY 1 89.SINGLE COPIES, TEN CENTS.VOL. XXII. NO. 546. J 1,89._$3.50 PER YEAR, IX ADVANCR.

CONTENTS. Walker Prizes in Natural Histo _j Pema'P^B-oketokofApaI bets, _ eng~~~~~~~~~~~~~~ravers,stone-cutters and'THE SOUTH DAKOTA ARTE5SIAN BASIN. W. S. Hfowar C r s PracticaYl LEeltetring' AIHIall . .... .............. 29 The Boston Soe.iety of N atIural H {story Universul Ha n y_Every-day Electrical MSat-A ROW OF HIEROGSLYPHS, CASA NO. .2, PALENQUE. offers a tlrst prize of from $60 to $100 and a secoind Iters, 135 pp., full ilisrted, 12mo, cloth, 75 cts.TEBO.iG NIT. Creso ......... ........ 30 |prize of a sum not exceeding $50 for the best me-Notes on Design ofSal Dynamo, by G. Halliday,

Wisow ..................31 moir.3 in English, on one of the following sub- $1. The Phonograpk and EIow to Construct It bTHE Booms OF THIIE PRAIRIE CHICKSEN. T. A. |jects: W. Gillett, 87 p., 12 fldin plates, 12mno, eloth, U.ABIKSINN Ae LRA .Greman .....33.....1. The relations of inflorescence to cross-fertiliza- St., New York. Illustrated and descriptive cata.

A SIK SPNNIG C:VE ARVA H. armn... 33tion illustrated by the plants of Eastern Massa_'! logues, 10 cts.A NEW ORTHOGRAPHY. J. D. Hinds .....................34 chusetts. IELECTRICAL NOTES. R. A. F ........... ......... 35 2. What depths of formerly overlying rocks, now The Batrachians and Reptiles of Indiana.A NEW INSTANCE OF STREAM CAPTURE. Hunter removed by denudation, may be inferred from the

l. Harris......... ............. 36, structure of various rocks in Eastern Massachu-INSECTIVOROUS PLANTS OF 'S'OU'TH FLORIDA. G. Isetts ? A Work of 204 pages, with 3 plates of 12 figures.W. Webster...... ...... .... .. 37 Contains full descriptions of nearly one hundred-QUANTITY.AND QUALITY OF MILK. W. W. Cooke. 38 3. Exrperiments affording evidence for or against !species of Batrachiaus and Reptiles, together withLETTERS TO THEIE EDITOR. | hhoyo vlto.Iof the species made easy by means of analyticalA. Unusual Aurora. W. H. Howard....................39 Each memoir must be accompanied by a sealed tables. Bz O.P. Hay, Ph.D. Price, in paper cover,Light-Shunners and Light-Seekers. J. W. |envelope enclosing the author's name and super- postpaid, V;100.Sflater................. ................... 39 scribed by a motto- correspoinding to one borna by Bowen-Merrill Book Co , Indianapolis, Ind.

The Aurora. M. A. Veeder ...... ...................... 40 ithe manuscript, and must be handed to the Secre-Natural Selection at Fault. J. W. Slater. .. 41: tary on or before April 1, 1894. CDU 1A monthly magazine for the studyThe Habitat and the Diet of the Lepidoptera. iPrizes will not be awarded unless the memoirs are GERMANrIA of the German language and litera-J. W. Slater. ....... ............ ..... 41 of adequate merit ......... ture. is highly recommended by college professorsBeaver Creek Meteorite. Edwin E. Howell. Al .dthe pruess as "tembfestefftortnytet matdheito assist

Enterd at he Pot-Offce ofNew Yrk, NY.,SAMUEL HENSHAW, Secretary. yeUaraiEtcomplletBeaGnId inEteresctinng coururnshein vermaEntered at the Post-OmceofNew Yorlr, N.Y., M |~~ grammar. $2 a year. Single copies 20 cents. P. O.Second-CMlass Mail Matter. Boston, July 3, 1893. Boxs 151, Manchester, N. H.

NEW METHOD OF PROTECTING BUILDINGS FRON LIGHTNING.SPARE THE ROD AND SPOIL THE HOUSE!

lZightning Destroys. Shall it be Your House or a Pound of Copper?

PROI'ECTION FROM LIGHTNING.What is the Problem ?

IN seeking a mieans of protection from lightning-discharges, we have in viewtwo objects,-the one the prevention of damage to butidings, anld the otherthe prevention of injury tolife. In order to destroy abulldijig illwhole orjlnpart, It isnecessary that work should be done;* that is, as physicists expressit, energy is reqi-iired. Just before the lightning-dischiarge takes place, theenergy capable of doing the damage which we seek to prevent exrigts in thecolumn of air extenlding from the cloud to the earth in some form that makesit capable of appearing as what we call electricity. We will therefore call itelectrical energy. What this electrical energy is, it is not necessary for us toconsider in this place; but that it exists there can be no doubt, as it manifestsitself In the destructionof buildings. The problem that we have to deal witbhtherefore, is the conversion of this energy into some other form, aud the ae-,complishment of this in such a way as sihall result in the least injuary to prop-eryndlie. 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 iscientificmen had not come to recognize the fact that the different forms of onergy-heat, electricity, mechanical power, etc.-were convertible one Into the other,and that each could produace just so much of each of the other forms, and no

more. The doctrtne ot the conservation and correlation of energy was firstclearly 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; andamong these were the attractinig power of points for an electric spark, and the-conducting power of metals. Lightning-rods were therefore introduced withthe idea that the electricity exristing in the lightning-discharge could be con-veyed around the<1building which it was proposed to protect, and that thebuilding 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 thoseinterested, lightning-rods constructed in accordance with Franklin's principlehave not furnished satisfactory protection. The reason for this is apparentwhen it is considered that the electrical energy existing in the atmospherebefore the discharge, or, more exactly,jin 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;* sothat the greatest display of energy will be on the surface of tbhe very lightning-rods that were meant to protect, and damage results, as so often proves to bethe case.It will be understood, of course, that this display of energy on the surfaeeof theold lightning-rods is aided by their being more or I zss insulated fromthe earth, but in any event the very existence of such a mass of metal as anold lightning-rod C8E1 only tend to produce a disastrous dissipation of electrical

energy upon Its surface,-"' to draw the ligbtning," as it is socommonly put.

Is,there a Better Means of Protection?HIaving cleared our minds, therefore, of any idea of conducting electrtelty,and keeping clearly in view the fact that in providlug protection against light-ulng we must furnish some means by which the electrical energy may beharmlessly dissipated, the question arises, "1Can an Improved form be givento the rod so that it shall aid In this dlssipation ?"

Page 2: 89.SINGLE P^B-oketokofApa · 2005-05-30 · menhadnotcometo recognizethefact that the different formsof onergy-heat, electricity, mechanicalpower,etc.-wereconvertible one Into theother,

SCIENCE [VOL. XXII. NO. 546

THE WINNIPEG COUNTRY;OR,

ROUGHING IT WITH AN ECLIPSE PARTY.BY

A. RO(HESTER FEL.I,OW.

(S. H. SCJDDER.)

With thirty-two Illustrations anid a Map.

12°. $1.50.IL, 10 PJLt UlIIOIlk tUUV Ul CIUtLLIUtttt "This is sprightly narrative of personal inci

dent. The book will be a pleasant reminder toSubscription, $3.00 per year. mnany of rough experiences on a frontier whichis

rapidly receding."--Boston Transcript.Youi can try it three months for fifty The picture of our desolate North-western terri-

cents. tory twenty-five years ago, in contrast with itsjcivilized aspect to-day, and the pleasant features ofthe writer's st3 le, constitute the claims of his little

Address: book to present attention."'-The Dial.

The Electrical Engineer,203Broadway, - - - NewYork,N.Y. N. D. C. HODGES, 874 Broadway, N. Y.

Every reader of "Science" should sub- BRENTAN O'S,scribe for the Publishers, Importers, Booksellers.

A I ~5 5 5 We make a specialty of technical works in all

AM kiE4 A N , C I T k CT, branches of science, and in all laniguages.AME'IZICAN AIZCIIITECT, ~Subscriptions taken for all Ainerican and foreign

THlE OLD)EST AND) BEST scientific periodicals.Our Paris and London branches enable us to im-

Architecttiral publication in the country. port at shortest notice and lowest prices. REPORTSInteresting articles on architecture. Sani- OF SCIENTIFIC SOCIETIES, MONOGRAPHS. GOVERNMENT

teRFPORTs. etc. Correspondence solicited.tation, Arebaeology, Decoration, etc., by the RFC7- All books reviewed in SCIENCE can be orderedablest writers. 1-ichlyj illustrated Is3ued fron? Us.

weekly. Send stamp for specimncn copy to SEN)FOR A SAMPLE COPY OF BOOK CHAT. AMonith-~~~~~lyrIndex of the Periodical Literature of the World.the publishers, $1.00 per year.

Ticknor & Co., 211 Tremont St., Boston BRENTANO'S, Union Square, New York,

- hicago, Washington, London, Paris.

"Extremely useful to beginners anid collectorsfor the region it covers."-Winz. fl. Dall.

MOLLUSKS OF TIlE 1S69. T H E 1893.

ATLANTIC COAST OF THE UNITED STATES, Manufacturer and Builder.South to Cape Hatteras.

By As7IN C. APAR This work contains a key to j bchisbedMonthy Ahandlsomelyillustratedme-all the genora. a glossary of Mollusean terms. de- Ehanical journal, edited by Drt. WIL.LIAm H. WAHL.

scriptions of all the species of shells, and over sixty Every number consists of 48 large quarto pages andillustrations. Fl 1 e l, Iill li ('1iIto. FPo-1 cover, fille(d with useful information on all subjectspaid, $ 1. For sale by AUSTIN C. APGAIR 511 of a practical nature. Specimen copy free. ForEast State St., Trenton, N. J. sale by all newsdealers. Agents wanted every-

where. Address

BUILDING 1893 Catalogueof Books oni Building,B O O K S . Painting, and Decoraling,also Catalogue of Draw-ing Instruinents and Ma-

n terials, sent free on appli-DRlAWVING cation to

WTm.T. Comstock,INSTRUMENTS. 23 Warren St., New York,

POPULAR MANUAL OF VISIBLE SPEECH ANGVOCAL PHYSIOLOGY.

For uWe in Colleges and Normal Schools. Price so centsSent free bv nost bv

HENRI CERARD,P. 0. Box 10)01. 83 Nas.au St., N. Y.

IAGIIT, IIEAT AND POWER.THE INDEPENDENT GAS JOURNAL

OF AMERICA.

PUBLISIIED MONI lILY ATr PHILADELPHIA.

.Subscription, $3.00 per year.

Newvspaper Clippivags. 25,000 in Stock.What do you want? Let us know. We(aln t4upply you. 'rhe Clemens News

N. D C. HODGES, 874 Broadway, N.Y. IAgency, Box 2329, San Francibco, Cal.

The Boston Medical and

BOSTON,

Surgical Journal.- - - MASSACHUSETTS.

A FIRST-CLASS WEEKLY MEDICAL NEWSPAPER. E5TABLI'HED 1828.

Ter ms of Su bserlpllou : In the United States, and to Canada and Mexico, $5 00 a year in advance. To Foleign Countries embraced in the Universal Postal Union, $1 56 a year additional. Singlenumbers, 15e. I en consecutive numbers free by mail on receipt of $1.00

This JOURNAL circulates chiefly through the New England States, and is seen by the great majorityof the profession in that impoitant district As a means of reaching physicians it is unequalled.

It is under the editorial management of Dr. George V. Shattuck, assisted by a large staff of compe-tent coadjutors. Subscriptions and advertisements received by the undersigned, to whom remiiittancesby mail should be sent by money-order, draft or registered letter.

DAMRELL & UPHAM, 283 Washington Street, Boston, Mass.

RACES AND PEOPLES.By DANIEL G. BRIN rON, M.D.

"The book is good,-thoroughly good, and will longrenmain the best accessible elementary ethnographyin our language."-The Christian Un ion.

"We strougly recommend Dr. Brinton's * Racesand Peoples' to both beginners and( scholars. Weare not aware of any other recent work on thescience of which it treats in the English language."-Asiatic Quarterly."His book is an excellent one, andl we can heartily

recommnend it as an introductory manual of ethnol-ogy."-The MIfonist."A useful anid really interestinig work, which de-

serves to be widely read and studied both in Europe

and America."-Brighton (Eng.) Herald.

"This volume is most stimulating. It is writtenwith great clearness, so that anybody can nuder-stand, and while in some ways. perforce, superficial,grasps very well the complete, field of hurnanity."-The New York Times."Dr. Brinton investshis scientific illustrations and

measurements with an indescribable charm of nar-

ration, so that 'Races and Peoples.' avowedly a rec-

ord of discovered facts, is in reality a strong stim-ulant to the imagination."-Philadelphiia PlublicLedger."The work is indispensable to the studenit who re-

quires an intelligernt guide to a course of ethno-graphic reading."-Philadelph ia Tinm es.

Priee, posilloall, $1.75.

THE AMERICAN RACE,By DANIEL G. BRINTON, M.D.

"The book is one of unusual interest and value."-Inter Ocean."Dr. Dauiel G. Brinton writes asthe acknowledged

authority of the subject."-Philadelphia Press." The work will bo of genuine value to all who

wish to know the substanice of what has been foundout about the indigenous Americans "-lature."A masterly discussion, and an example of the

successful education of the powers of observation."-Ph iladelph ia Ledger.

Price, Io0tpatii(, $2.

FOSSIL RESINS.This book is the result of an attempt t6

collect the scattere(d niotices of fossil resins,exclusive of those on amber. The work is ofinterest also oii accouilt of descr iptionis givenof the insects foundl emibedded in these long-preserved exudationis fromii early vegetation.

By CLARENCE LOWN and HENRY BOOTH.12g. I.l.

N. D. C. HODGES, 874 Broadway, N. Y.

LABORATORY MICROSCOPES.The Reichert III (ver-

tical, No. 8) is a favor-ite pattern for labora-tory work, and is fitte(dwith his best lenses.

le are prepa? ed to

intport the abore instru-

nients, duty free, for

edutcationtal itstit'tioils,at extremiely locv piices.

Correspondence So'icited.

-j*, QUEEN & CO,,

Sole Agents. Philarlelphia.

Probably yout take

TIIE

Electrical Engineer.Most people interested in Electricity

do.If you do not, now is a good time to

begin.Tt- -Q -11 1 1-1ilnl=1'5- 1D1 *1

Page 3: 89.SINGLE P^B-oketokofApa · 2005-05-30 · menhadnotcometo recognizethefact that the different formsof onergy-heat, electricity, mechanicalpower,etc.-wereconvertible one Into theother,

40 SCIENCE.It is well known in various countries that fishes swim up to a

boat on a strearn if a light is displayed on board.An interesting spectacle is produced if a candle, or better still

an el&tric glow lamnp is brought near the glass sides of anaquarium. Fishes, aquatic lar'.ae and mullusca swim up andseek to come as near as possible to the light.Numbers of nocturnal insects are attracted by flame. Moths,

gnats, crane-flies and many other (lipte-a are noted for their pro-pensity to commit suicide in our lamps an(d candles. Many ofthe sm-aller moths are found sitting on the glasses or the ironframe-work of street-lamps. I have known an old lady made illwith fright becauise a death's-head (AchePontia atropos) had flownagainst her candle and ptlt it out.But we must now glance at the main question, that is, tile

meaning of the behavior of nocturnal animals in presence of alight. The alarm of many species is not hard to understand.A b-iglit light is a pheenomenon which does not fall witlhii thelinmits of their experience anid seemas to them, therefore some-thing to be avoided. But to see nocturnal, abysrmial or cave-dwelling species flocking to a liglht is perplexing.

It has been suggested that the moth thinks the flame an outletthrouglh whichi it may escape. But Why slhould it seek to escapefroimi a condition which to it is as normsal as is sunliglht to thebuttei fly or to the bee? it has again been suggested that noctur-nal insects and fishes are able to preceive the faint phosphorescentliglit app)arently given off by nmany flowers, and by aquatic-worms, etc.. Hence the moth rushes to the lamp mistaking it fora flower. On coming nearer hle is bewildlered by tlhe intensity ofthe light and ' loses his head." This same suplposition explainswhy mosquitoes are less attracted by a lamp than are nmost otherinsects. They are not accustomiied to find their fool in phos-phorescent flowers, hence the lamp has to them little attraction.

True, this hypothesis fails to shlow why birds should dash them-selves against thle windows of a lighthouse. Their normal foodis not phosphorescent. Nor, to our knowledge, are their eyescapable of perceiving a faint phosphorescent light.

LVOL. XXII. No. 546

Probably no single hypothesis will meet all the cases of the at-traction of animals to light. J. W. SLATER.

Londoni, EnglaLd.

The Aurora.

The contradiction in certain statemeents of mine wvith referenceto the possibility of tracing the relation of the aurora to disturb-ances upon a paiticular part of the sun in certain years whichProfessor Aslhe thinks he has detected and wlhich he puts intoitalics at page 9 of Scieniee for Julv 7 amiounts to simply tbis:In one sentence which he quotes I anm giving the reason why therelation in question comes out distinctly in years of nminiiiiuli,namely, because the disturbances are well separated fiom eachother, and, taking 1879 as an examsple, show by a table that thiswas the case in that year, in whichl both auroras and sunspotswere so very fewv that the numbers to be employed were so ex-tremely small that it rnight justly be doubted whetlher they showanything, and yet, in spite of this disadvaantage, nanrely, thesmallness of the numbers, the relation was plainly apparent. Inanother sentence, referring to the nmatter froim this point of view,namely, the size of the numbers to be employed, I state that itn1880 the relation in this respect would be Imluch miiore distinct,this also being a year of comparative minimuml in whiclh the dis-turbances were well separated from-i eachl otlher, so that the con-clusion with reference to this year contained in the sentencewlhich Professor Asche quotes would( he Itully justified, i.e., thenumbers would he larger anid the relation in every way nmore dis-tinct." The only reason for the publication of the table for 1879was to show w hat would appear in the year in which ve mnightsuppose the relationi exceptionally difficult to trace anid yet inwhich it was distinctly apparent in spite of the smiallness of tlenumbers. It was simply picking out 'he worst possible case, aswe 'would naturally suppose, instead of the best possible case,and it is to its discussion that the sentences whichi ProfessorAshe quotes, refer. M. A. VEEDER.Lyonis, N. Y., July 13.

Reading Matter Notices.Ripans Tabules: best liver tonic.Ripans Tabules cure Jaundice.

B ACK NUMBERS and complete setsof leading MaLazines. Rates 'ow. AM. MAG. EXCHANGE.Schoharie, N. Y.

RESTORE YOUR EYESIGHTCataracts, scars or films can be absorbed and

paralyzed nervcs restored, without the knifeor risk. Diseased eyes or lids can be cured byour home treatment. "We prove it." Hun.dreds convinced. Our illustrated pamphlet,'Home Treatment for Eyes "free. Don't miss it.Everybody wants it. " Tuz EkY," Glens Falls N.Y.

WORLD-ENGLISH.2.5 Cesst%.

HANDBOOK 0 FAWORLJiWORLD-ENGLISH.

25 Ceasts.Exs- President Andrew D.

White, of Cornell University,says: "I believe thatthe highest interests of Chsis-tian civilization and of humanity would be servedby its adoption."" So set down, our tongue is the best for the world

to unite upon."-Brooklyn Eagle." The idea of Mr. Bell has much to recommend it,

and the presentation is charmingly clear."-American, Phila."The result is a language which cannot fail to

meet with acceptance."-Boston Traveller."World English deserves the careful consideration

of all serious scholars."-Modern Language Notes.

Sent, postpaid, on receipt of price.

N. D. C. HODGES, 874 Broadway, N. Y.

CURES WHERE AALL ELSE FAILS. iBest Cough Syrup. Tastes Good. Use

I!H In time. Sold by druggists. -

1I41i 4&!JiLI IaI

A-

_L~TE11Sm ~ :

THE MODERN MALADY; or, Suf-ferers from ' Nerves.

An introduction to public considerationi,from a non-medical point of view, of a con-

dition of ill-health which is increasinglyprevalent in all ranks of society. In thefirst part of this work the author dwells on

the errors in our mode of treating Neuras-thenia, consequent on the wi(le ignorance ofthe subject which still prevails, in the sec-

ond part, attention is drawn to the principalcauses of the malady. The allegory formingthe Introduction to Part I. gives a brief his-tory of nervous exhaustion and the modes oftreatment which have at various times beenthought suitable to this nmost painful and try-ing disease.

By CYRIL BENNETT.12°, 184 pp., $1.50.

N. D. C. HODGES, 874 Broadway, NewYork

Pennsylvania Bedford Springs Mineral WaterFor Liver, Kidney and Bladder Troubles.FI'or Gravel, Gall Stones, Jaundice.For Dyspepsia, Rheumatism and Gout.For Dropsy, Bright's Disease, Diabetes.For Hemorrheids, Etc.It has been used medicisially and prescribed by

pbysicianis for nearly one hundred years.DIRECTIONS:-Take onie or two glasses about a

half-hour before each meal.Case One Dozen Half-Gallon Bottles, $4.50.Case Fifty Quarts (Aerated), $7.50.

Bedford Mineral Springs Co., Bedford, Pa:Philadelphia Offlee, 1004 Walnut St.

STERBROOK'SSTEEL PENS.

OF SUPERIOR AND S1ANDARD QUALITY.Leading Nos.: 048, 14,130, 135, 239, 333

For Sale by all Stationers.

THE ESTERBROOK 8TEEL PEN CO.Works: Oamden, N.J. 26JJohn St., NewVYork.

New Store.MI|| NERAn^LS. NNewv Stock.MIERS Nexv Departinelits.Send for our "Wiiiter Bulletiu," recently issued.

Minerals, Gems, Microscopical Sectious, Fine Lap-idary Work.

GEO. L. ENGLISH & CO., Mineralogists,Removed to 64 East 12th Street, New York

oAGEfTS $50 to $l001jjsLadh or (-utu. Btosciler kno-n. Ntd-

p ed atev ryhus place of bu.hies, orfrrmtheyearround. "Itlnme" Electrie lloair

' ruis al kinid.of lighlt manchinlery, Chanp-emt poweronu arth. Conuected iustantly towash or sewing machine, corn shellVrpumps, fans, lathes. j-velers or dentists

nmachiuerv, &c Clean, noiseless, lassIalife-time. No exoreience needed. To.oliow in operation mineans a sale. Guar.

I anteed. Profits immense. Cirrulars free.llARRISON & CO., X-T, Col-mbus, 0.