42 
SCIENCE. 
[Vol. XXIII. No. 572 
1,000,000 
young mothers need 
pyhood 
ighest authority 
The 
on the care of children, deal- 
ing with food, dress, instruction, ete. 
One hundred physicians write for it. 
“Tt will save the child an illness, the 
mother many a sleepless night.” 
Worth its weight in gold."—Boston Transcript. 
$1.00 a Year 
Babyhood Publishing Co, New York. 
1IS69. THE ISYS. 
Manufacturer and Builder. 
Published Monthly. A handsomely illustrated me- 
chanical journal, edited by Dr. WitL1am H. WABL. 
Every number consists of 48 large quarto pages and 
THE MODERN MALADY ; or, Suf- 
~ ferers from ‘ Nerves,’ 
An introduction to public consideration, 
from a non-medical point of view, of a con- 
dition of ill-health which is increasingly 
prevalent in all ranks of society. In the 
first part of this work the author dwells on 
the errors in our mode of treating Neuras- 
thenia, consequent on the wide ignorance of 
the subject which still prevails; in the sec- 
ond part, attention is drawn to the principal 
causes of the malady. The allegory forming 
the Introduction to Part I. gives a brief his- 
tory of nervous exhaustion and the modes of 
treatment which have at various times been 
thought suitable to this most painful and try- 
ing disease. 
THE WINNIPEG COUNTRY; 
OR, 
ROUGHING IT WITH AN ECLIPSE PARTY. 
BY 
A. ROCHESTER FELLOW. 
(S. H. SCUDDER.) | 
With thirty-two Illustrations and a Map. 
12°. $1.50. 
“This is a sprightly narrative of personal inci 
dent. The book will be a pleasant reminder to 
many of rough experiences on a frontier which is 
rapidly receding.” —Boston Transcript. 
“The picture of our desolate North-western terri- 
tory twenty-five years ago, in contrast with its 
civilized aspect to-day, and the pleasant features of 
the writer’s style, constitute the claims of his little 
book to present attention.”—The Dial. 
os 
cover, filled with useful information on all subjects 
of a practical nature. Specimen copy free. For 
sale by all newsdealers, Agents wanted every- 
where. Address 
HENRI CERARD, 
P. O. Box 1001. 83 Nassau St.,N. W. 
DELSARTE SYSTEM OF ORATORY. 
A Book of over 600 pages of great value to all 
Delsartians, teachers of elocution, public speakers, 
singers, actors, sculptors, painters, psychologists, 
theologians, scholars in any department of science, 
art and thought. 
Price, $2.50, postpaid. 
EDGAR S. WERNER, Publisher, 
108 East 16th Street. - = - New York. 
By CYRIL BENNETT. 
12°, 184 pp., $1.50. 
N. D.C. HODGES, 
874 Broadway. New York 
N. D. C. HODGES, 874 Broadway, N. Y. 
SCIENCE CLUBBING RATES. 
10% DISCOUNT. 
We will allow the above discount to any 
subscriber to Science who will send us an 
order for periodicals exceeding $10, counting 
each at its full price. 
N. D.C HODGES, 874 Broadway, N. Y. 
NEW METHOD OF PROTECTING BUILDINGS FROM LIGHTNING. 
SPARE THE ROD AND SPOIL THE HOUSE ! 
Lightning Destroys. Shalt it be Your House ora Pound of Copper? 
PROTECTION FROM LIGHTNING. 
What is the Problem? 
In seeking a means of protection from lightning-discharges, we have in view 
two objects,— the one the prevention of damage to buildings, aud 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 Iightniug-discharge 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 thatit 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 iuto some other form, and the ac- 
complishment of this in such a way as shall result in the least injury to prop- 
erty and life. ic 
Why Have the Old Rods Failed? 
When lightning-rods were first proposed, the science of energetics was en- 
tlrely 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. 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 ii apparent 
when it is considered that the Olectrical 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 maxtmum valu > on the sur- 
face of the conductors that chance to be within the column of dielectric; so 
that the greatest display of energy will b3 onthe surface of the very lightning- 
rods that were meant to protect, and damage results, as so offen proves to be 
the case. 
It will be understood, of course, that this display of energy on the surface 
of the old lightning-rods 1s aided by thelr belug more ort s4 insulated from 
the earth, but in any event the very existence of such a mass of metal as an 
old lightning-rod can only tend to produce a disastrous dissipation of clectrical 
energy upon its surface,— ‘‘ to draw ths jightuing,” as it 1s 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 tbat in providing protection against light- 
ning we must furnish some means hy which the electrical energy may be 
harmlessly dissipated, the question arises, ‘‘Can an improved form be given 
tothe rod sothatitshalls. ‘n this dissipation?” 
§ 
~ 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 that the total amount 
of metal running from the top of the house tesome point a little below the 
foundations shall not exceed one pound. Suppose, again, that we introduce 
numerous insulating joints in thisrod. We shall then have a rod that experi- 
ence shows will be readily destroyed —will be readily dissipated —whena 
discharge takes place; an 1 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 damage. 
The only point that remains to be proved as to the utility of such a rod 1s to 
show that the dissipation of such a conductor does not tend to injure other 
bodies in its immediate vicinity. On this point I can 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); butin every case that I have found recorded this dissipation 
takes place just as gunpowder burns when spread onaboard. The objects 
agalpst wich the conductor rests 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, inaletter to Collinson read before the London Royal 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 tail 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 ceiling of that 
second floor, till it came near a plastered wall; then down by the side o! that 
wall to aclock, which stood about twenty feet below the bell. The wire was 
not bigger thana 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 E- 
the church stood, so that nothing remained above the bell. The lighbtring 
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, alittle bigger), and 
without hurting the plastered wall, or any part of the building, so far as the 
aforesaid wire and the pendulum-wire of the clock extended ; which latter 
wire was about the thickness of a goose-quill. From the end of the pendu- 
lum, down quite to the ground, the builjing was exceedingly rent and dam- 
agei. ... No part of the aforementioned1l ng, small wire, between the clock 
aud the hammer, zouid be 7ound, except about two inches that hung to the 
tat! -ftue hammer, and about as much that was fastened to the clock; the 
rest being exploded, and its particles dissipated in smoke and alr. as gun- 
powder is by common fire, and had only left a black smuity track on the plas- 
tering, three or four inches broad, darkest in the middl*, and fainter towards 
the edges, all along the ceiling, under which it passed, aud down the wall.” 
Dre aundred 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 five dollars ($5). 
Correspondence solicited. Agents wanted. 
AMERICAN LIGHTNING PROTECTION CO., 
874 Broadway. New York Citv. 
