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Shall it be your house or a

Can any reader of Science cite

a case of lightning stroke in OF HARTFORD, CONN., pound of copper?

which the dissipation of a small Entirely new departure in pro- conductor (one-sixteenth of an

tecting buildings from lightning: inch in diameter, say,) has failed Largest Accident Company in the

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conductor is dissipated the buildFOREMOST LIFE COMPANY dress, on receipt of five dollars. ing is not injured to the extent

explained (for many of these see OF NEW ENGLAND. Correspondence solicited. Agents wanted.

volumes of Philosophical TransAssets, $15,029,921.09

AMERICAN LIGHTNING PROTECTION CO., actions at the time when lightSurplus, 82,579,794.24 874 Broadway, New York City.

ning was attracting the attention

of the Royal Society), but not Fact and Theory Papers an exception is yet known, al PAID POLICY-HOLDERS $1,798,000 IN 1892.

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VOL. XXII. No, 545.

JULY 14, 1893.



Walker Prizes in Natural History. You Ought to Read

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


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, 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 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 enegy. 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

in the destruction of bulldings. 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 prop-
erty and life.

Why Have the Old Rods Failed ?
When lightning-rods were Arst proposed, the science of energetics was en-
tirely undeveloped; that is to say, in ihe middle of the last century scientific
men had not come to recognize the fact that the different forms of energy –
best, 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 me'als. 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
bullding would thus be saved.

The question as to dissipation of the energy involved was entirtly Ignored,
Daturally; and from that time to this, in spite of the best endeavors of those
joierested, 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, 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 dlelectric; 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 less 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 electrical
energy upon its surface, -" to draw the ligbtning," 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
barmlessly dissipated, the question arises, “ Can an improved form be given
to the rod, so that it shall ald 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 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 to some poiut a little below the
foundations shall not exceed one pound. Suppose, again, that we introduce
numerous insulating joints in this rod. We shall iben have a rod that experi-
ence shows will be readily destroyed - will be readily dissipated – when &
discharge takes place; and it will be evident, that, so far as the electrical en-
ergy is consumed in doing this, there will be ine less to do other damage.

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 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 & confined space wiihout 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
against witch the conductor regts may be stalned, 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 dig.
sipated on the surface of a comparatirely small or easily dissipated conductor.
When dissipated on the surface of a large conductor, - a conductcr so strong
as to resist the explosive effect, -damage results to objec's 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 Collineon read before the London Royal Society,
Dec. 18, 1755, describing the partial destruct!on by lightulng 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 ceiling 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 beli. The wire was
not bigger than a common kuitting needle. The spire was split all to pleco
by the lightning, and the parts fluog in all directions over the square in which
the church stood, so that nothing remained above the bell. The lightrirg
passed between the hammer and the clock in the above-mentioned wire
without hurting elther of the floors, or having any effect upon them (except
making the gimlet-holes, through whleh the wire passed, a lile 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; whii h latter
wire was about the thickness of a goose-qu'll. From the end of the pendu-
lum, down quite to the ground, the building was exceedlogly rent and dam.
aged. . . No part of the aforementioned long, small wire, between the clock
and the hammer, could be found, except about two inches that hung to the
tail of the 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 smutty track on the plas-
tering, three or four inches broad, darkest in the middle, and fainter towards
the edges, all along the ceiling, under which it passed, and down the wall."

One hundred feet of the Hodges Patent Lightning Dispeller (made ulder
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grass weeds, leaves, hair, cotton, wool, rags, paper and eren

other materials enter into its composition. In shape it is more THE WRENS OF TRAVIS COUNTY, TEXAS.

or less rounded, with an entrance in the side. The eggs are four,

fire or six in number, fire being most common. BY CHARLES D. OLDRIGHT, AUSTIN, TEXAS.

There is not much variation in the eggs; the markings being in 1. Catherpes Mexicunus conspersus, Cañon Wren. This bird some heavier than in others. The ground color is white, spotted is an “endemic” species, its occurrence in any district depend thickly and finely with specks of reddish-salmon color and slilac, ing on the topographic features. The great rock walls of the generally forming a poorly defined ring around the crown.

The Colorado River, and the numerous side cañons form an ideal ground color is usually well concealed. dwelling-place for this little bird, and here it may be found at Fresh eggs may be found from April 1 to May 15, the height all seasons, and its loud, ringing song re-echoes from cliff to cliff of the breeding season being during the middle of April. in the dreary days of November as well as in April's sunsbine. 3. Thryothorus bewickii murinus, Baird's Wren. But it penetrates into the city, and every morning this year one Probably our co:nmonest wren, found in all kinds of country, of the first sounds that I have heard has been the matutinal song bottoms or uplands, forest or prairies, mountains or plains. I of a cañon wren whose nest was in a cranny of an unoccupied beliere, however, that Baird's wren prefers a broken country, house standing next to mine.

little patches of prairie ani mesquite groves alternating with the The cañon wren (as active a busy-body as the rest of his tribe) timber. seems to be never too tired to sing. Reclining on the soft grass A number of these birls must spend their whole lives in at the margin of the rivulet you look up the great frowning cliff the city of Austin, for in nearly every garden one may find a and see a tiny bird, now clinging to the perpendicular rock, now pair. disappearing in some crevice of the cliff and then perching on a They are fussy little creatures bardly ever silent for a moment projecting fragment, he utters a succession of clear bell-like notes but keeping up a lively chatter or querulous “ chee, [chee, chee." in a descending scale.

But all through the spring, even as early as January, the males As this wren usually nests in some crevice far up in the cañon are great singers, and early on an April inorning one cannot go wall its eggs are often safe from the hands of the oölogist. far without hearing the sweet and cheerful song of one of these Many times bave I gazed longingly at a few straws projecting little birds. At such times one finds the bird perched in a tree-top, from a bole, wbile the owner of the nest watched me compla but on other occasions he will be hopping amongst the bushes or cently. In such cases “'tis distance lends enchantment to the along a rail fence, flirting his long tail, uttering a continuous view." However, I have had the pleasure of examining several "chirp, chirp," and at each third "chirp” stopping a moment to pests containing eggs and young, and as I have never seen any pour forth his little ditty. This is kept up for hours at a time. detailed account of the nidefication of this species, I will give In February the wrens become restless and may be seen some particulars about them.

promenading t'ie back yards in pairs peering in to every hole and This bird begins building early in the season, a nest with bird-box. They seem to be often undecided as to a nesting place', hatching eggs in it having been taken on the 30th day of March. for I have known of a pair starting four different nests within a In 1890 fresh eggs were found April 3, 4 and 11.

week, without any apparent cause for their fickleness. Any The nest is placed in some cranny or hole of convenient size, place seems good enough for this bird to start a nest—though as always in the face of the cliff; other situations are on a rafter in I bave just stated they are more particular about its final location. a barn, under the cornice on a veranda and in the chimney of an Many people here have put small wooden boxes at their gates for uninhabited house.

the reception of mail matter, and I verily believe that each one is The nest is composed of grass and weeds and lined warmly looked into once a year by a Baird's wren, with a view to building with hair, wool and cotton. The complement of eggs varies in it, and indeed many are chosen as nesting sites. from three to five, four being perhaps more usual than either of The nest is simply a mass of rubbish – but always warmly and the other numbers.

softly lined with feathers or cotton. Six is a common compleThe eggs always bare a clear white ground, while the mark ment of eggs, but as many as eight or as few as four may conings vary from a very slight sprinkling of brown pin-points to stitute a full set. The eggs are white, more or less speckled with numerous large blotches and spots of reddish-brown and lilac, brown of varying shades and lilac, so:netimes the specks of redforming a confluent ring encircling the crown; this is the most dish brown are thickly and uniformly distributed, again they are common pattern of coloration. Their shape is ovate or rounded collected into a ring surrounding the crown or else rather larger ovate, but I have seen ope pyriform egg in the nest with three specks of chocolate brown and lilac shell markings are more other pormally shaped eggs.

sparingly disposed. 2. Phryathorus ludovicianus, Carolina Wren. An abundant Two “albino” eggs came under my notice last spring; one was bird in the bottom lands along brooks and in all heavily timbered immaculate white, the other had a very faint speckling on the country. The Carolina wren is another fine singer, but spends crown; both these eggs were with other normally colored eggs. too much of its time in scolding owls, crows and men. But I also found a peculiar "runt” egg of this species, it is of normal often, especially in the spring and at sunset on a summer's day, coloration but measures only .55 by .44, being thus the size of a one of these birds will perch on the topmost twig of a tall shrub humming bird's egg. I fund it one day in a hole in a telephone and will, with his tail drooping and head thrown back, call pole, and left it thinking that more eggs might be laid, as I saw "sweet Williamı " until the woods resound. By the way, “sweet the birds at band; but when, after the lapse of several days, pone William " does not express tbe exact sound of the bird's notes to were deposited, I took it. Why the bird laid no more I do not me, but I am so hopeless of expressing birds' voices by English know. Surprise at the first one may have had something to do words that I will not attempt to amend it.

with it. This bird cannot be called particular in its choice of a nesting 4. Troglodytes aëdon aztecus, Western House Wren. place, for their nests have been found in hollow logs, under the Of this member of the family I can say but little, for during cornice of a house, in a tin can placed in a tree, in a hole in a his winter stay with us he is very silent and indeed shy. rock wall and on the window sill of a farmhouse. The hollow I am aware that he, like his kinsmen, cin scold with remarklog is, I beliere, the most usual situation. The nest is made to able vehemence, for I have heard him. While he remains with fit the cranny in which it is built and generally fills it. Twigs, us he is to be found in the creek bottoms wherever there are

tbickets of brush.wood. He remains with us until late in the Spring, indeed the other wrens have young ones before he thinks of leaving for his northern summering place.” Last year I saw some on the 22nd of April. I sept one of them to Washington where the “bird doctors” pronounced it "aztecus,"

5. Salpinctes obsoletus, Rock Wren.

This bird hardly deserves a place to itself, being quite uncommon and differing little in appearance and mode of life from the Cañon wren, which seems to represent it with us. It is more common furtber west. Indeed, this is ihe most easterly record in Texas of its occurrence.

of petroleum. If great quantities of iron carbide existed beneath the earth's surface and were subjected to decomposing influences, such oils and gases as are found in petroleum regions might sery easily be formed.

So far there has been little utilization of these carbides commercially. One of the purer forms of iron carbide is used in a process for preparing metallic sodium, and the iron carbide in cast iron confers upon it many of its useful properties. If these bodies can be produced cheaply enough, bowever, there is strong probability tbat certain of them will prore very useful.


BY F. P. VENABLE, CHAPLE HILL, N. C. Tuis name is given to compounds formed by the direct union of carbon with the metals. They are not numerous nor do they seem to be easy of formation and it is rery difficult to prepare them in a pure and definite form. Consequently they have been but little studied so far. None of them are known to occur in minerals of terrestrial origin.

Interest in these bodies has been heightened of late by the discovery of new ones, and by the instructive decompositious of some of them.

First as to the general mode of formation. They are usually formed by the action of intense beat upon the metal in the presence of carbon. The form of this carbon is capable of being greatly varied. Graphite, amorphous carbon and many hydrocarbons can be used. The carbide is especially formed when the metal is being extracted from its compounds, that is, in the nascept state. Several metals thus unite with carbon in the process of manufacture, as zinc, copper and notably iron, and the presence of the carbides renders the metal hard and brittle. 1 he purification and analysis of these bodies is not at all an easy problem, and hence little or nothing is known of their formulas or chemical constitution Five or more formulas have been assigned to iron carbide, and, of course, several may exist, still the correctness of any of these formulas is questionable.

The heat of the ordinary furnace is sufficient to form the carbides of the metals already mentioned. For others, more recently discovered, as the carbides of aluminium, of calcium, of barium, etc., the intense heat of the electric furnace is necessary. The first of these, aluminium carbide, is a most interesting body, of a light golden yellow color, it can be gotten from t'e electric furnace in a mass of corundum and metallic aluminium. It was described first by Sterry Hunt. Though it will stand intense heat in the air without appreciable change, yet really it is undergoing change all the time as is proved by the oder of hydrocarbons coming from it and the fact that left to itself in air it cruinbles in a few weeks into a mass of white alumina. A few shining golden scales of the pure substance can be separated, but so far no analysis has been given to the world.

All of these carbides, under certain conditions, give off their carbon in the form of hydrocarbons. The same smell can be detected in all during their decomposition. In some cases, as iron and zinc, the decomposition is caused by the action of an acid. The carbides of the earths decompose in moist air and more rapidly in water. Calcium carbide decomposes the most energetically of them all. The erolution of the hydrocarbons would be called violent. Of course, the hydrogen needed for the reaction comes from the decomposition of the water or from the hydrogen acid.

Amst interesting fact recently publisbed in the scientific journals, is that the calcium carbide on decomposition yields live and pure acetylen gas. The acetylen seems very pure: A thousand cu. cm. of the evolved gas was passed into an ammoniacal solution of copper chloride, and not a bubble went through. All was absorbed and precipitated. This is very important because the modes of preparing acetylen in common use are tedious or expensive, and hence this important hydrocarbon has not been as carefully studied as it otherwise might have been.

The formation of hydrocarbons by the decomposition of iron carbide has furnished a basis for one of the theories as to the origin

PHILOSOPHY IN TIE COLLEGE CURRICULUJI. BY HOLMES DYSINGER, CARTHAGE COLLEGE, CARTHAGE, ILL. STUDIES under the name of philosophy are to be found in almost every college curriculum. Either bt cause the subject is too vague or abstruse for the counprehension of the average student, little more than elementary sychology, which is rigbily regarded as a lecessary part to the introduction to the subject proper, and a brief discussion of practical ethics are taught in most of the schools outside of the few real üniversities. While the number of subjects advocated for introduction into the college course is increasing constantly, one so fundamental as philosophy should not be neglected. Apart from its theoretical value, it has practical bearings upon the intellectual range of a mar, regardless of the system he adopts, that commend it to the thoughtful consideration of educators.

The subject matter with which pbilosophy deals bears a peculiar relation to all other subjects in the course, in as much as its office is, partly at least, to systematize and explain all the principles of the particular sciences. This gives the unity so desirable in a course of study, and so essential to the thoroughly-trained mind. From this it serves the highest purpose in education and deserves a prominent place in every course of liberal culture.

The philosophical jowers of man are last in order of development. The subject-matter makes it necessarily so. It is the most abstruse of all forms of knowledge. The mind in its unfo'ding passes up through perception and conception to the realm of widest generalizations and the discovery of the principles that are assumed in all our thinking. Philosophy deals with forms of knowledge that stand at the farthest remove from that furnished in so-called presentation the first clevelopment in the mind's unfolding.

When the mind reaches that stage of development in which it apprehends the principles fundamental to all knowledge, it turns in upon itself and critically examines its own processes and assumptions to determine the certainty of being and the validity of our knowledge. This is the bighest stage in man's intellectual ascent. Here he stops. He has completed the circuit of the globe of knowledge. He started with the facts furpisbed in sense and consciousness, and ends in the principles that underlie and embrace all knowledge. These stand accredited in his own thinking. Beyond this the mind of man cannot penetrate.

That many students cannot attain this stage of knowledge is evident to all who have taught the upper classes in our colleges ; that but few who attempt it get further than the outer court. is to be expected ; but that all are greatly benefitted intellectually would not be denied by those who have looked into the merits of the case and examined the evidence with impartiality. A few additional facts will give our reasons for this conclusion.

Notwithstanding its abstruseness, as a discipline in thinking and in logical method, philosophy has no equal. Facts as furnished by the senses and distinguished from principles are not dealt with in philosophy, but the relation of facts to one another and to all things else. All these in a system of philosophy deserving of study or worth elaboration must be included in their relations of coördination and subordination. The unity of all bzing is tbe ultimate problem of philosophy. A narrower range and lower ideal may satisfy science, but it cannot attain to that which comprehends all know ledge. Only the mind well disciplined in logical method can grasp the facts, but the one who attempts to do so will derelop a power that is the possession of few and the desire of all.

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