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55

NEW METHOD OF PROTECTING BUILDINGS FROM LIGHTNING. SPARE THE ROD AND SPOIL THE HOUSE! Lightning Destroys. Shall it be Your House or a 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, 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 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 accomplishment of this in such a way as shall result in the least injury to property and life.

Why Have the Old Rods Failed?

When lightning-rods were first proposed, the science of energetics was entirely 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 energyheat, 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 conveyed 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 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 surface of the conductors that chance to be within the columu of dielectric; so that the greatest display of energy will be on the surface of the very lightningrods 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 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 lightning 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 aid in this dissipation?

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As the electrical energy involved manifests itself on the surface of conductors, 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 point a little below the foundations shall not exceed one pound. Suppose, again, that we introduce numerous insulating joints in this rod. We shall then have a rod that experience shows will be readily destroyed-will be readily dissipated - when a discharge takes place; and it will be evident, that, so far as the electrical energy 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 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 dissipated, 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 against which the conductor rests may be stalued, but they are not shattered, I would therefore make clear this distinction between the action of electrical energy when dissipated on the surface of a large conductor and when dissipated 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 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 tall of the hammer a wire went down through a smali 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 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 piece by the lightning, and the parts flung in all directions over the square in which the church stood, so that nothing remained above the bell. The lightring passed between the hammer and the clock in the above-mentioned wre without hurting either of the floors, or having any effect upon them (except making the gimlet-holes, through which the wire passed, a little 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 pendulum, down quite to the ground, the building was exceedingly rent and damaged. 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 air, as gunpowder is by common fire, and had only left a black smutty track on the plastering, 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 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 City.

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SYSTEMATIZED GRADUATE INSTRUCTION IN PSYCHOL

OGY.

BY E. W. SCRIPTURE, NEW HAVEN, CONN.

Instruction in psychology cannot be said to have been placed on a sound basis till it consists of a series of carefully graded teaching from elementary text-book instruction to the highest kind of original work. Haphazard work here is just as bad as anywhere. It is self-evident that the student of psychology should properly apportion the amount of time spent in its various departments and in the other sciences he will have need of. The man who starts with the supposition that the way to study psychology is to go into the anatomical laboratory on the one hand and to take heavy courses in Greek philosophy on the other, is losing much valuable time. It is hereby not implied that no time is to be given to these subjects any more than that geometry and history are to be omitted from a man's education. But when a man has finished his college work and goes to the university he is supposed to have received his general culture and to be ready for his lifework.

The specialist is a man of broader knowledge than the dilettante.

The difference between the two is that the latter browses at random, while the former reaches over a much wider field, but with a careful selection and coördination of the portions related to some central point. There is a maximum of energy and health which a man can employ in work; if this capital is inrested in a careless way it will bring in small returns; the man will never really gain a complete training in anything.

The problem of a specialist is to go over as much ground as possible; to do this it is necessary to pass rapidly over the less valuable portions in order to have time for the valuable ones further on. Moreover, no essentials should be overlooked, no matter how distant they apparently lie. This last requirement is probably the most important of all. There is many a psychologist to-day who is fatally weak in some one or more points; it would be easy to find those who, although making measurements, know nothing of the science of measurement, or who, using light, heat, etc., as tools in their experiments, have little idea of the laws of the forces they are handling. To remedy all these defects in the dilettante way a man would have to study a couple dozen sciences; since life is too short to learn even one with any respectable thoroughness, the only way to do is to take just what will be of the most advantage to the psychologist, always bearing in mind that an hour too much on any one point means an hour too little on some other one.

It is the first problem of the psychological laboratory or the psychological department to so arrange its courses as to satisfy these requirements. As my own experience may possibly be of use to some one I will indicate briefly the outline of a system of instruction designed to meet this want. It is to be borne in mind that I am not speaking of college work with the object of general culture, but of serious university work for one who desires to study psychology.

As the science of psychology to-day is based on measurement and experiment, the work of the student must begin with some considerations on the method of making experiments; this should be followed by careful work in the theory of measurements, treating of the probability integral, the mean variation, etc. This work resembles somewhat the corresponding work given in physical measurement, but although the mathematical princi

ples are the same, the treatment differs considerably. One of the great differences between psychological and physical measurements is that the conditions cannot yet be as accurately controlled as in physics; our mean variations are thus greater and the deductions we can draw from the results are not the same. In this respect psychological measurements on a single person somewhat resemble measurements taken once on each of a large number of persons. Partly for this reason, but mainly also for the sake of mental statistics, a study of the methods of statistics has to be made. The making of measurements brings in the study of fundamental and derived units and the construction of apparatus. The study of the various subjects of touch, sight, hearing, etc., requires a consideration of the physical processes used in stimulation. Thereafter the usual psychological subjects are, in a lecture course, to be treated in detail.

Hearing lectures will never make a psychologist; the fundamental course for all special instruction is the laboratory work. The student must be trained by repeated exercises in making the measurements explained in the lectures, including exercises on touch, temperature, hearing, sight, in the graphic method, chronometry, dynamometry, audiometry, photoptometry, colorimetry (psychological), etc. This should be followed by work in the construction of apparatus, elements of mechanical drawing, use of tools, etc. It is of great importance not to have too many men at work at the same time, at least not until psychological laboratories are much enlarged. During the past year the average attendance on this course in the Yale laboratory has been eight, an unpracticable number. Even with the enlarged equipment for the coming academic year, the number admitted to this practice course will have to be limited.

The object of university instruction, as distinguished from college training, is to develop the love of research, to train the student in research methods, to furnish him with the requisite knowledge and skill, and finally to provide him with the apparatus and other means of work for carrying out such investigations as may be best for him to undertake. The requisite knowledge of the psychological methods is gained from the laboratory course, the training in the difficulties and methods involved in research is obtained by placing the newer students as helpers to the advanced ones. The importance of this last arrangement can hardly be overestimated. It is the one in vogue at Leipzig and elsewhere.

It is a very dangerous thing for a man to take up a problem for investigation unless by previous experience with some one else he has found out that research is the hardest kind of work and has learned the thinking, the untiring patience, the courage under defeat that are called for at the various stages of work.

If we regard the research work as a means of training, it is an important matter to the student that he shall not undertake problems with rather indefinite boundaries or those where he may perchance run wild or be led into careless work. There can be no better training than that found in the investigation of a single point where the most careful measurements and manipulation are required. Once the student has learned the proper habits he will do far better work with suggestive and uncertain problems than could otherwise be hoped for.

If a student has had the proper general culture in philosophy, physics and mathematics, such a course as that outlined ought to make a thorough psychologist out of him. If he has not had the proper college training it behooves him to make it up as fast as possible. In the first place, an acquaintance with German is absolutely indispensable. Some acquaintance with the epistemological theories of the day is also necessary. A thorough scientist in psychology could not get along without knowing some

thing about calculus, at least enough to follow the developments in such works as Müller's Grundlegung or Weinstein's Physikalische Maassbestimmungen. The more physics he knows the better.

OUR CRIPPLED WEATHER SERVICE.

BY JAMES P. HALL, BROOKLYN, N.Y.

A recent order of the new Secretary of Agriculture stops all the scientific research which, until this month, was being conducted by the United States Weather Bureau, and limits the functions of the experts in the Central Office to mere forecasting. Quite apart from all personal and political considerations, this is a lamentable event on many accounts.

64

It appears to be necessary, even in this enlightened age, to prove afresh that "pure science" is a prerequisite to most of our material progress. We are still under the necessity of making out that Columbus, who conceived that other lands lay to the westward of the great Atlantic, who visited one potentate after another to secure aid for his schemes, who haunted the courts and camps of Ferdinand and Isabella year after year, and who backed up his case with only the calculations of "pure science," really served Spain in particular, and civilization in general, quite as well as the practical" men who handled the ropes and sails of the three caravels. We must elaborately demonstrate, all over again, to some of our fellow-countrymen that the unknown inventor of the mariner's compass and those other " pure scientists" who make charts showing the deviation of the needle, have conferred as great benefits on mankind as the pilot who uses that quivering bit of steel in bringing his ship safely across the seas. We must be prepared to face a question whether the captain of a New England fishing smack who thumbs his almanac to find out at what hour the tide rises or falls on a given day is not, after all, the superior (as an agent in civilization) to those learned astronomers and mathematicians who compute the tables for that little pamphlet. We must not be surprised if sane, intelligent, even eminent men, tell us that all the amazing development in steel production which we have witnessed in Europe and America in the last quarter of a century would have come just as soonperhaps sooner—if Henry Bessemer had not carefully evolved his wonderful process from chemical theories and laboratory tests, nor ought it to startle us if some one insists that the sweating laborer in a rail mill, who grasps with tongs the fiery snake which emerges from the rollers and drags it away to have its ends sawed off, does more toward the building of a safe and lasting road than the expert who sits at a table and figures out the precise cross-section of rail that will give the greatest resistance to all the complex strains to which those bars must be subjected in service, even though these calculations extend over years and are based on long-extended and carefully designed tests. not count on the universal acceptance of our opinion-if it happens to be our opinion-that Roebling, in computing the exact size and number of the wires to hold up a bridge over East River, and in drafting all the plans for that wonderful structure, was at all comparable in usefulness with the truckman who now drives a two-horse team across it every day. If we positively assert that the projectors of the great railway systems beyond the Mississippi have done more than the men who drove spikes with sledge hammers to open up that region to settlement and to provide outlets for the enormous grain and pork product which has resulted, we know not how soon nor how flatly we shall be contradicted. We may meekly hint that the physician who prescribes does as much to cure us as the drug clerk who compounds the prescription; that the arithmetic maker is as much of a public benefactor as the corner grocery man who foots up the total cost of ten pounds of sugar and two pounds of coffee; that Edison, who perfected the incandescent lamp after long years of experiment with no end of substances for his filament, did as much to give us an electric light as the man who tacks up cloth-covered wire in our offices and screws pear-shaped globes into wallfixtures; that Graham Bell was quite as instrumental in enabling us to converse over a wire with people a dozen miles away as the patient girl who answers our ring and sticks a little brass plug in a hole for us; and that we owe as much to the long array of de

We can

signers, from Watts to Buchanan, who have brought the locomotive engine up to its present perfection, as the engineer on the "limited" express for the marvellous speed we make in going to Chicago; but we must not mistake for conviction the tolerance with which these utterances are received.

And so in meteorology. There are minds so constituted that they regard the observer as the equal or superior of the inventor of the barometer and thermometer; the "practical" man who jots down figures on a map and then draws "isobars," "isotherms" and wind signs on it as more useful than the pure scientist who, without touching pencil to paper, studies the movements of high and low pressure areas across the country, and the man who guesses what changes will occur during the next twenty-four hours, in the shape, size, position, intensity and other features of the cyclonic and anti-cyclonic systems, are doing better work than one who discovers and formulates the laws that govern those changes, and thus renders forecasting possible. What makes this the more amazing is the insufficiency of our present rules for weather predictions. The principles involved are not yet fully established. The most successful experts in this line realize that they are working under only a provisional code that must be greatly modified and supplemented. There is not a science so young and undeveloped as meteorology; there is not a bureau in the national government whose maxims and procedure are not better established, nor, when one considers the immense and varied interests-railway, shipping, agricultural, commercial and individual-which are affected by the weather, is there any branch of the service which affects so many people, and affects them so directly, as this, unless we except the postal business? Not to strain every nerve to improve the quality and character of the work by fuller inquiry into fundamental theories is folly, if not crime. Such a policy of neglect involves direct waste, as ignorance always does. Our expenditure, year after year, would not thus be made to the best possible advantage. On the other hand, to use one per cent ($10,000), out of the $1,000,000 appropriated for the bureau, in expert work, would be a measure of true economy by gradually revealing how best to use the rest. That has been true of the bureau from the start; and it has never been a wiser course than it would be now. Any manager of a creamery, sawmill, cotton factory, iron foùndry or railroad who deliberately threw away such a chance as this for improving what everyone recognized as the inadequate facilities of his business, at a trifling cost, would be set down by "practical" men as strangely blind or culpably reckless.

ANALOGOUS VARIATIONS IN SPHAGNACEÆ (PEATMOSSES).

BY H. N. DIXON, F. L. S., NORTHAMPTON, ENGLAND. IN the 66 Origin of Species" (6th ed, p. 126) there is the following passage, under the heading of "Analogous Variations: " "As all the species of the same genus are supposed to be descended from a common progenitor, it ought to be expected that they would occasionally vary in an analogous manner, so that the varieties of two or more species would resemble each other, or that a variety of one species would resemble in certain characters another and distinct species, this other species being, according to our view, only a well-marked and permanent variety."

A clear example of this is of considerable value in the support it gives to the theory of descent; but, as Darwin goes on to show, there are several reasons why such examples are not common.

A very striking illustration is, however, to be seen among the peat-mosses, or species of Sphagnum, and, as I do not know that anyone has drawn attention to the facts from this point of view, I think it may be of interest to present them briefly. Many of the facts quoted below are taken from a paper by C. Jensen (translated in the Revue Bryologigue, 1887, p. 33. by F. Gravet), entitled "Les Variations Analogues dans les Sphagnaceés."

Sphagnum acutifolium may be taken as a typical species of the genus; in its most characteristic form it is a plant with tall, slender stems, bearing at intervals fascicles of simple branches of two kinds, the one (divergent) stouter and more or less horizontal,

the other (pendent) longer, thinner, straight, and appressed closely downwards to the stem; the leaves on the branches being closely imbricated all round. The stem bears leaves very different in form and structure from those of the branches.

Now Sphagnum acutifolium is a most variable moss; the list of recognized species in Europe alone numbering about thirty. Among these are several distinct and well-marked forms, such as the following: In one the branch leaves, instead of being straight and closely imbricated as described above, are bent back in the middle and spread almost at right-angles from the branch - the forma squarrosa. In a second the branches, instead of being straight or nearly so, are hooked or contorted - the falcate variety. In a third, the forma compacta, the whole plant takes a short, compact habit, the stems being much shortened and closely tufted, the fascicles of branches close together, and the branches themselves short and stunted, with the leaves closely set. In a fourth the differentiation between the stem and branch leaves almost or quite disappears, the former acquiring the form and structure of the latter, the forma homophylla, and so on with two or three more distinct varieties.

Now, if we turn to the other species of the genus, we find that of those found in Europe and North America there is hardly one which does not include one or more of these six or seven distinct varieties which we find in S. acutifolium. Thus of nineteen European species (all but two of which are natives of North America) sixteen, and perhaps eighteen, bave varieties belonging to the forma compacta, fourteen at least, and perhaps four others, have the squarrose variety, and so on to a greater or less degree with the other forms. At least two of these forms are found under every one of the species, and in more than one species all the forms are found.

Here we have a clear case of analogous variations. It cannot be supposed that they are instances of reversion to a common ancestral form, for, apart from other considerations, the variation in some of the forms is in a directly opposite direction to that which it takes in others. The delicate, elongated forms of the tenellæ and the dense, compact forms of the compactæ can hardly both be reversions to a common ancestral type!

So far we have exactly the same thing that we see in many races of domesticated species, such as Darwin has pointed out, for instance, in the races of the domestic pigeon; but we do not often see it carried out on such a wide and instructive scale.

But what is of especial interest in the case of the Sphagnacea is that, when we go further and consider the characters that distinguish the different species from one another, we find that the very points which we have seen mark off the above varieties (and render them, as a rule, more distinct than the other varieties of the species) are in several cases those which are most characteristic in separating from one another the species themselves. Thus S. squarrosum is specially marked by the spreading leaves; S. rigidum has for its most obvious features the very characteristics by which the compacta forms above described are distinguished; S. subsecundum in most of its forms is marked by its falcate or contorted branches; while a group of species, classed by Lindberg as HOMOPHYLLA, are characterized by that similarity of stem and branch leaves which I have described above as the feature of the corresponding variety; and so on with the other forms.

Here we

have exactly fulfilled the supposition of Darwin quoted above, "that a variety of one species would resemble in certain characters another and a distinct species," and fulfilled, too, on a scale which, at any rate, precludes the possibility of its being due to fortuitous coincidence.

On any theory of creation that did not presuppose a common ancestry for these species of Sphagnum, it might indeed be possible to account for the analogy between the varieties of different species by assuming the variations to be the direct results of the environment (a more than doubtful assumption, moreover); but the more we lay this cause under contribution to account for the varietal forms, the harder it is to believe that precisely the same variations in the species, only carried out to a higher degree of permanency, are due to entirely different and quite unconnected

causes.

The above facts appear to me to form a peculiarly interesting

support to Darwin's argument from analogous variation. In the first place, the possibility of reversion is, as I have pointed out, eliminated, and reversion and analogous variation, which are quite distinct principles, are too often indistinguishable in their results for us to be quite certain that we have a genuine example of the latter. In the next place, as Darwin points out, analogous variations are liable to be eliminated as not being necessarily serviceable; that they are not eliminated in the Sphagna is, I believe, partly due to the peculiar conditions under which these plants usually grow, but this opens too wide a field to enter upon here. In addition to these reasons, we have here an illustration drawn from species and varieties in a state of nature; examples of analogous variations have usually to be drawn from domesticated forms, where their value is limited by their necessarily applying to races and varieties only, and not to distinct species.

I append a table (taken from Jensen's paper quoted above), which shows at a glance the distribution of these varietal forms among the European species of Sphagnum. At indicates the existence of the variety heading the column under the species opposite to which it is placed; a ? means that the existence of such a form is probable, but is insufficiently attested or not clearly enough marked to be entered as certain. It must be remembered that there is always a possibility of gaps being filled up by future research, but the table is, I think, as it stands, sufficiently striking.

THE CLOSE OF THE ICE AGE IN NORTH AMERICA. BY R. W. MCFARLAND, LL.D, LATE PRESIDENT OF MIAMI UNIVERSITY. THIS is a question of interest to scientific men in general, and to geologists and glacialists in particular.

In Professor Wright's "Ice Age in North America,” p. 448, in speaking of Croll's table of the eccentricity of the earth's orbit, he says: "According to this table the modern period most favorable to the production of a glacial epoch began about 240,000 years ago, and ended 70,000 years ago." Again, on p. 450, we have this: "If, therefore, the glacial period should prove to have ended only 10,000 years ago, instead of 70,000, the Darwinian would be relieved of no small embarrassment."

A genuine scientist, of course, has no preconceived theory to