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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 lujury 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 couveyed 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 the 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 column 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 1-ss 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 poiut 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 experlence shows will be readily destroyed-will be readily dissipated when a discharge takes place; an 1 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 bodles in its immediate vicinity. On this poin: 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 cour-e, it is readily understood that such an explosion cannot take place in a confined space with out the rupture of the walls (the wire cannot be boarded over); but in every case that I have found recorded this dissipation takes lace jist as gunpowder burns when spread on a board. The objects against w ich the conductor rests may be stained, 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 lightuing 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 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 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 wire 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 bullding, 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 builting 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 alr, 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, postpald, to any address, on receipt of five dollars ($5).

Correspondence solicited. Agents wanted. AMERICAN LIGHTNING PROTECTION CO.. 874 Broadway, New York Citv.

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NEW YORK, SEPTEMBER 8, 1893.

THE MARINE BIOLOGICAL LABORATORY.

BY DALLAS L. SHARP, BRIDGETON, N. J.

THE sixth summer session of the Marine Biological Laboratory, at Wood's Holl, Mass., ended with August '93, and a short review of the station, of its work and growth, will be of interest to Science readers, throughout the country, who are at all interested in our advancement in biological thought and investigation.

The phenomenal growth and spendid proportions of the Marine Biological Laboratory, as it now stands, justly deserve the interest and admiration of every educated American.

Starting six years ago, in 1888, the Laboratory was but a single building of two large rooms, poorly equipped for work, with only one boat for collecting material, and a total of seventeen students. The session of '93 opened with three connected buildings more than twice as large as the original, containing thirty-four private rooms, a lecture room, a library, a supply department, five general laboratories, and a total of one hundred and twelve students. Instead of a single row-boat, there are now several at the Laboratory's wharf and beside these a splendid Burgessbuilt steam launch perfectly equipped for collecting and always at the students' command.

The secret of this extraordinary growth is mainly due to the Laboratory's ideal foundation, its location, its officers and the high grade of its work.

In 1881, at Annisquam, a quaint little fishing village on Cape Ann, the Woman's Educational Society of Boston started a small laboratory for the study of marine zoology For six years investigation was carried on here, with constantly increasing demands for better and more accomodations, until the necessity of a permanent and better equipped laboratory brought together a number of Boston scientists, who were organized into a corporation under the name of the Marine Biological Laboratory.

Thus it came into existence, and though started in Boston it is by no means a local institution. It can hardly be called national, for students from Maine to California work side by side with those from England, Germany and Japan. Its board of trustees includes a large proportion of America's most prominent scientists, and their aim is to make the Laboratory an institution second to none of its kind in the world.

The location of the Laboratory at Wood's Holl is most happy. It was not the result of luck or chance. Over twenty years ago the late Professor Spencer F. Baird, of the Smithsonian Institution, recognized the advantages of Wood's Holl for the study of marine life, and for many years he and his assistants came here and worked through the summer months. As a result of his work, the United States has established here her most important fishing station, whose buildings are the finest of their kind in the world. Nowhere along the Atlantic coast do the American waters offer more varied or richer fields for the naturalist,

Looking off to the southward from a Laboratory window, Martha's Vineyard is seen stretching away in the distance till its point is lost behind Nonameset, which in turn is followed by Naushon, by Nashuena, by Cuttyhunk and others. Behind to the west lies Buzzard's Bay with its distant shore and the little Weepecket Islands like dots upon its surface. In front again is Vineyard Sound, the Harbor, Wood's Hole, Quick's Hole, and other holes innumerable, all teeming with life and all within easy reach of the student.

What a happy hunting ground! What variety of forms! What wealth of numbers! What a paradise for the naturalist! The sandy shores, the rocky points, the muddy bays, the tide-pools, holes and bottoms from the depths in Vineyard Sound to the shallows of Buzzard's Bay, are all astir with life which the student may study at first hand.

After a year's study at the Laboratory the average student wakes up to the fact that he never knew before what the study of zoology or botany meant.

He is no longer looking at "stuffed things" wired fast to sticks, or withered, shrunken, faded stuff in glass bottles. The specimens are not stuffed with tow nor wired to the rocks, which he gathers from the shores at Wood's Holl, nor do thy float around in alcohol. He learns many new names, but does not spend the summer committing to memory the check-list of species on the coast. He returns to his teaching or college with a larger idea of life; to his reading and work asking how and why and when. He returns to every thing with renewed vigor and enthusiasm, except to the college museum.

The work done at the Laboratory is divided into two very distinct divisions. The institution is at once a centre for the advancement and for the diffusion of knowledge; it is a school for teaching and a station for research: and acordingly the students who annually attend are divided by a distinct line into pupils and investigators. In the first category come those who have had but an elementary course in zoology, who are practically unacquainted with the methods of work, who must needs have a broad and general knowledge of the structure of the various groups of animals, must become acquainted with the great principles of biology, and the use of the naturalist's instruments, before they can engage in original research.

For the needs of this class of students the Marine Biological Laboratory is eminently fitted. In no other institution of its kind has this department been so fully and thoroughly developed. The Marine Biological Laboratory is unique in this. It stands alone. It is an entirely new departure, and the student who intends to teach or work in any line of biological investigation has an advantage here that is entirely without equal.

Each student has his regular table, his locker for instruments, his own reagents and complete outfit for work. In the centre of the room are the aquaria where his living material is kept. Here he may work, as long as he likes, with abundant material, free to ask questions, and with some eniment biologist always at hand in case of difficulty.

The instruction is largely personal. From 9 till 10 A. M. there is a general lecture, bearing on the form that is to be studied that day. This lecture is always given by some specialist in that particular group. To-day, for instance, the form under study will be a sponge; the morning lecture then will be by some investigator who is making sponges his special study. After this lecture the day is given up to study, and the instructors are always near, with criticism and suggestion, clearing away the difficulties as they arise, until the student, working form after form, gradually masters the technique and learns in part to interpret facts for himself.

After this course, if he chooses to return another year and persue the work further, he takes a table in the upper laboratory, where he is given some problem to solve, which is not too difficult, and here again he is helped over the hard places, until, having had sufficient preliminary training, he is capable of choosing and solving his own problems. For those who carry on special investigations private rooms are provided, where they may work undisturbed and in perfect quiet.

This year there are thirty-four of these rooms, each occupied by some investigator, working at some problem whose solution will have an important bearing on the scientific thought of the day.

This summer gathering of our biologists and scientists at the Marine Biological Laboratory, apart from the natural advantages of the place, is of the greatest help and importance. There is an enthusiasm and stimulus in the numbers and personal contact which nothing else gives. Men of different schools, working in widely separated fields, here meet and compare ideas and methods. Their lines of work continually cross and the help of a specialist's suggestions at these points cannot be overestimated. Hardly a paper goes to press, but that it has first received the honest judgment and criticism of those whom the author most wishes to reach.

Every point of interest and doubt is carefully weighed and discussed, and very seldom does error escape detection. As often happened this year, papers which have been long in preparation, and discoveries that are entirely new, are delivered as lectures before the whole student body, and are afterward discussed, allowing every one the privilege of expressing his criticism and opinion. This is not only of immense value to the author, but all present are thus kept in the very van of scientific thought.

The student who wishes to come to Wood's Holl does not necessarily need to be working some problem of marine life, to enjoy the advantages of the Laboratory. His work may be such that requires the fresh-water ponds, or the woods and fields, it may be; if so, they are all at hand. The character of the surrounding land is almost as varied as that of the water. The green and rolling and rolling hills, the winding road-ways, the quiet, shady ponds, all combine to make the country round about Wood's Holl a land of delight to the summer visitor, whether he be student or pleasure seeker.

One of the newest features of the Marine Biological Laboratory is the Department of Physiology. This was first opened last year under Dr. Jacques Loeb, of the University of Chicago. This year professors from Harvard Medical School, the College of Physicians and Surgeons, from Johns Hopkins and other such schools have occupied the rooms and have placed the department on a sure and successful footing.

The Botanical Department gave a course in Cryptogamic Botany in reference to marine algae and a parallel course in comparative forms of Fungi. The department was crowded, several specialists investigating problems connected with marine plant-life.

The "Supply Department" of the Laboratory, while it is a side issue and of no special concern to the summer student, is nevertheless an institution of great interest and importance to every zoological teacher in the country. The collecting is under the care of Mr. F. W. Wamsley, who has had much experience in the work, and he has reduced the business of collecting, killing and preserving, to a science.

Full data accompany every specimen. The date, even the hour in some cases, the location, depth of water, character of bottom, and many other minor details, are carefully noted. Then the killing fluid is tested and proportioned, and so on through every step in the process of fixing the tissues, which is often very complicated, until the specimen is finally preserved in the proper alcohol. As the value of a zoological specimen preserved for class use, or for histological purposes, depends entirely upon the methods used in its preservation, it should be, and is, a source of great satisfaction to know that the Marine Biological Laboratory has established a department where such material can be supplied, which formerly could not well be had short of Naples.

The excellent library of the Laboratory is at all times. open to the student. The Laboratory is a regular subscriber to about thirty of the leading biological and other scientific papers of our own and foreign countries. Besides this, the Boston Society of Natural History has generously placed the use of their library at the disposal of the Laboratory, and the library at the Laboratory has been in this way effectively supplemented.

The evening lecture course for the session of '93 was like that of former years, dealing mainly with subjects of general interest. Night after night the little lecture room was crowded with the students and their friends and the people from the village.

Such, in brief outline, is the Marine Biological Laboratory at the close of its sixth year.

We are justly proud of what it has been and now is. Its short history is one of severest struggle. What it now is, is owing to the generosity and earnest labor of a few; what it is to be, depends, in part, on your generosity and mine. What it may be, is summed up in these few words from the last report of its director, Dr. C. O. Whitman, "We have now seen about the limit of what can be accomplished without funds. The two functions of instruction and investigation have worked admirably together, each growing stronger in the success of the other. We have endeavored to keep the two properly balanced, but I think we have nearly reached the limit of our capacity for instruction with our present space and means. We already see that to tax our teaching forces much more, would not tend to improve the side of investigation. For further development, then, two things have to be provided, namely, room and funds. As we cannot well enlarge our building, and as the conditions for both branches of our work could be immensely improved by providing a separate building for the investigators, our next step is clearly defined: It is a suitable observatory for the exclusive use of those engaged in original research. Preparatory to this, a site is to be selected and secured. This done, the plan of the building worked out, the equipment estimated, the income necessary to the maintenance of the observatory, with its officers and scientific staff ascertained, we shall be prepared to lay the whole matter before any one who may be disposed to contribute to the foundation of a biological observatory-an observatory which shall be an honor to America, and worthy of that promising science of the future to which the world looks for grander discoveries than have yet enriched human knowledge or contributed to the welfare and advancement of the race."

SCIENCE:

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HOW CHEMISTRY IS BEST TAUGHT.*

BY CHARLES F. MABERY, CASE SCHOOL OF SCIENCE, CLEVELAND, OHIO.

THE subject "How chemistry is best taught," which has been proposed to us for discussion, has a serious interest for all persons who are engaged in teaching chemistry, and it is of especial importance to those of us who have in charge the preparation of young men for professional employment. In view of the prominence of scientific subjects and methods in the present systems of education, it is incumbent upon the adherents of these methods to demonstrate by their results that they are not in error in assuming that science should have an equivalent place with other departments of knowledge. In the higher institutions this question has received a definite answer; in the secondary schools evidently much has yet to be accomplished in the direction of general education as well as in the preparation for higher study.

That the importance of a knowledge of elementary chemistry is apparent to all who are capable of appreciating its usefulness, is evident in the recent extension of instruction in the secondary schools. In the larger portion of our high schools, however, physical science still occupies a subordinate place, or it is taught merely from text-books with little, if any, laboratory training. Probably the chief hindrance to any radical change is a lack of appreciation on the part of the public. If parents could be brought to see that their sons and daughters would receive a better education if physical science properly taught formed an essential feature of the high school course, the change would not be long delayed. That the training of many teachers is scarcely more comprehensive than they are called upon to impart is of less importance, since at present those who are educated in the higher institutions have better opportunities, and those who are deficient can improve their knowledge in special courses for teachers. Doubtless the many popular movements of the present day will exert a beneficial influence in extending an acquaintance with the application of scientific principles. Such unique and instructive object lessons as that which has been designed, under the direction of Prof. Ellen H. Richards, for the Rumford kitchen, in the Columbian Exposition, cannot fail to attract public attention. It requires no particular training in observation to recognize the difference in nutrition of foods which have a widely different nutritive value; but

*A paper read before the section of Didactic Chemistry in the World's Congress Auxiliary of the World's Columbian Exposition at Chicago, August 26, 1893.

when an an appetite whetted to the sharpest edge in an endeavor to see all the exhibits in the Liberal Arts building in one visit, and the unavailing efforts to extract a crumb of comfort from the places so improperly named, is brought in contact with the wholesome dishes prepared in the Rumford kitchen, and their satisfying influence, the numbers representing the food values will be in a favorable connection to awaken a desire for further information. The same principle is applied in a different manner in the exhibits from the agricultural stations which explain the composition of dairy products, of animal foods and the methods of chemical investigations. These exhibits have a particular interest for persons engaged in agricultural pursuits since they are a part of the well-directed efforts of the stations in disseminating knowledge. Probably in no department of education has there been a more substantial growth during the last twenty years than on the part of intelligent farmers in applying the practical information coming to them from the results of investigations carried on at the experiment stations. These illustrations may seem somewhat removed from the main question before us, but I am convinced that the efficiency of higher instruction in chemistry will be greatly improved when students coming to us from the secondary schools shall have had the advantage of practical training in elementary physical science, and I believe this will be the sooner accomplished through a recognition of its benefits in the affairs of every-day life. I think we shall all agree that the best argument to be urged in favor of a prominent place for chemistry in any grade of instruction is the value of experimental methods for the development of mental power. This feature should naturally appear with especial prominence in courses leading to the degree of Bachelor of Arts; and if the schools of science are to be maintained on a higher plane than the trade schools or shops, the courses of study must be conducted with reference to the attainment of mental discipline and scholarship. In the courses in chemistry I am unable to see why this should interfere with the acquisition of practical knowledge.

With

The guiding star to successful teaching in chemistry is the personality and enthusiasm of the instructor. the great increase in attendance in many institutions the earlier relations between student and instructor, which were frequently mingled with deep personal feeling, somewhat akin to veneration on the part of the student, are well-nigh impossible. Nevertheless, an enthusiastic teacher with tact and good judgment has little difficulty in maintaining a profound interest even in large classes. In successful teaching we all know how much depends upon the attitude of the instructor toward his students. Courteous relations, with a clear understanding that teacher and students are mutually interested in the acquisition of knowledge, readily secure the confidence and esteem of a body of students, and the instruction need seldom be interrupted by questions of conduct. A faithful teacher does not limit his attention to the brighter minds; students slow in comprehension but earnest in application secure a store of information which will be used later to the best advantage. It was a wise teacher who said: "I am faithful in my duty to dull students; in my old age I may need favors of the men of wealth."

In assimilating their methods from European laboratories, the chemists of the United States, untrammelled by traditions and unrestrained by the influence of any particular school, have been in favorable conditions to appreciate the labors of the great masters of other countries. Unfortunately, it may be, in the wonderful development of our natural resources, the temptation to enjoy material benefits may have retarded the growth of orig

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