is not easily melted or weakened by heat, and above all it is inexpensive and easily handled. The field is a great one, and both the theory and the practise of steel and concrete combinations enter, or should enter, into the curriculum of every student of civil engineering and architecture. In the Austrian building at the recent fair in St. Louis there was a model of the centering of an arch, evidently steel-concrete, of 80 meters span (262 feet). You will remember that the beautiful and imposing 'Cabin John Bridge,' built of granite, in Washington, D. C., the greatest stone arch in the United States, has a span of 220 feet. The recent enormous increase in the manufacture of Portland cement is an indication of the coming demand. It has taken thousands, perhaps millions, of years in the laboratory of nature, to produce the masses of granite and the layers of marble and limestone; the engineer and the chemist, working together, produce from the abundant supplies of material near at hand an artificial masonry in a few hours. Of its strength and durability the engineering laboratory and a brief experience tell us much.

The verdict of a thousand years is still to be rendered, but here again the hand of promise points our way.

AERIAL NAVIGATION.

Above I casually mentioned air ships. You must bear with me while I say several things about aerial navigation.

We have been accustomed to regard the problem of practically navigating the air as one which could not be solved, or, at any rate, as a sort of fad hardly deserving of mention in connection with engineering. It will be remembered that the late eminent engineer, Professor J. B. Johnson, would not admit that aerial navigation was a possibility. He classed it with the problem of perpetual motion. But a careful examination of all the conditions seems to me to

point towards the possibility of progress, and all that we can at present claim for many desirable improvements is that they admit of progress. We can not with any confidence predict the rate of progress. Some of the things I have already pointed out bear directly upon the problem of aerial navigation; two in particular: The use of tubular constructions for the maximum of strength and the minimum of weight; and the construction of motors which are strong and light; but many problems must be solved before we can really navigate the air.

It was my privilege to be connected with the discussion of aerial matters at the late fair in St. Louis. Without my knowledge I was selected as the president of the aeronautic congress, in which the problems of aeronautics were carefully discussed. That congress had no functions whatever in regard to aerial exhibits, or attempts to exhibit air ships, at the world's fair. The latter feature of the fair I regret to say was a deplorable failure. The greater part of the failure was inevitable, since aerial experimentation is expensive and difficult, and it has very rarely been undertaken by scientific people. What has been anywhere in that direction has been for the most part crude, ill-advised and unscientific, and failures have generally attended any attempts to actually navigate the air. Of course there are exceptions in the character of the investigations made. I could mention four Americans who are approaching the problem carefully and on scientific lines. Some of their investigations and experiments are full of promise for the future of aerial navigation.

So far as the failure of the spectacular part of aeronautics at the fair was concerned, that failure was due very largely to the vandalism of some crazy crank or rival, who cruelly mutilated the air ship brought over by Santos Dumont at great expense, to be used during the summer in

St. Louis; and especially was the failure due to the most unfortunate and unwarranted charge which a police officer made in response to a call for a report in regard to the mutilation of 'Santos-Dumont No. 7.' Being unable to get any clue to the guilty wretch (who had plenty of time to slip in and slash the gathered silk in hundreds of places while the guard sipped his coffee in a booth a few hundred yards away), and feeling doubtless that he must give some explanation, he actually stated that in his opinion the injury was inflicted either by Santos-Dumont himself or by some one of his men. No more injurious, unwarranted or insensate charge could have been made, and no person who was in any way acquainted with Santos Dumont could have made it; and yet that charge became current in the newspapers and was half believed by a great many very respectable people far and wide. Doubtless the currency of that charge did much to discourage and repel Santos Dumont from our shores. That he should have received such treatment in America was surprising and greatly to be regretted. It went far to give us a bad reputation in European circles. We are credited with hostility towards European inventors and experimenters. I trust Mr. Santos Dumont may eventually learn that Americans as a rule are fair-minded, generous and friendly towards all experimenters in every field. I trust he may learn that not one, so far as I know, of the gentlemen who were associated with him during his two visits to St. Louis sympathizes in any way, or to any extent, with the insinuations thrown out against him by the officer above referred to.

From this digression I now turn to the subject in hand, namely, the possibility of progress in the art of aerial navigation. Regarding progress in aerial navigation as entirely possible, I notice that it depends

upon the solution of many problems, and no successful air-ship can reasonably be expected to appear until these problems are solved.

There are two lines of attack, which, while differing in one respect, have very much in common. Investigators are naturally divided into two classes: One seeking to devise methods for navigating the air as birds do, which gain support and propulsion solely from mechanical and muscular energy; and the other relying for support, more or less, upon the buoyancy of hydrogen gas, while securing propulsion by means of propellers. All are clearly interested in motors, whether the air-ship moves with or without the support of a bag of hydrogen. All are concerned with methods of management, and with the adoption of means for directing the movements of an air ship through the air.

If a gas bag is to be used, it is evident that the shape of the bag which involves the least amount of resistance is of first importance, and if that bag is to be a diminishing quantity, the ship must secure support from the use of aeroplanes or curved surfaces as the craft is driven rapidly forward. It is evident that the character of supporting surfaces and their distribution are matters of first importance in all cases. The number of preliminary lemmas which must be solved before the main proposition is reached is readily seen. The recent aeronautical congress concerned itself wholly with discussions and reports of experiments upon these preliminary matters, and I can truthfully say that excellent work was done.

I spoke of the gas bag as being a diminishing quantity. minishing quantity. I wish to add a few words to make my meaning clear. When it was first proposed to propel an ocean ship by means of mechanical power, it was assumed as a matter of course that the

ship itself could float upon the water, and that mechanism was to be employed solely for the purpose of driving it forward and for steering it. In aerial navigation the case is different. The ship is not only to be driven forward, but it must be supported. The analogous case, therefore, is not that of an ocean ship, but of a heavy swimmer who must both support and drive himself forward. Swimming does not come to boy or girl by nature, and the skillful teacher furnishes a temporary support while the learner masters the art of using his hands, feet and legs correctly. cordingly, he applies either a buoyant bag of air between the boy's shoulders, or the gentle lift of a string attached to a pole, and thus supports the learner while he masters the mechanical details of swimming. This exterior lift or support is a diminishing quantity as the pupil progresses, and when correct motions are learned and become automatic, the pupil swims and external aid is no longer necessary.

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Similarly, as it seems to me, aerial navigation is to be accomplished. At first the craft may very properly be supported by a bag of hydrogen. Something must hold the structure which is to carry motor, propellers, fuel, ballast, steering apparatus, aero-planes, etc., above the ground, in comparatively still air, while tests can be made and skill in management can be acquired. Infinite patience, plenty of money and first-class engineering culture and skill will be required. The various elements must be studied one at a time, while a friendly gas bag holds the experimenter aloft. When an engineer can build a durable and wellportioned motor and system of propellers, which shall be as strong as twenty horses and only as heavy as twenty geese; and when he can drive his supporting bag of hydrogen through the air at the rate of twenty or thirty miles per hour, he can re

duce the size of his bag and get support from aeroplanes and curved surfaces, and learn to manage them. The smaller the gas bag, the less the resistance of the air; consequently a greater velocity; consequently a greater lift of the aero-surfaces; and again a less demand upon the hydrogen -and so on, to final victory. American skill, ingenuity and experience will triumph provided that experience is cumulative. Men must learn from twenty failures how to succeed the twenty-first time in one thing. As I said: Patience, money and time are necessary. I wish Andrew Carnegie, or some other 'captain of industry who is in danger of dying rich, would establish and endow an 'aeronautical experiment station and laboratory,' and then place it in charge of a physicist like Professor Zahm, and an accomplished mechanical engineer like Mr. Blank. In ten years such men, under such conditions, would go far towards a solution of the problem of aerial navigation.

FUNDAMENTAL PRINCIPLES.

Some one proposed to teach a nation patriotism by writing popular songs for its schools. There was a world of wisdom in the suggestion, for the foundations of character and the guiding principles of life are generally laid at school. That is why the great teacher is such a power in the world.

Is it not so in-engineering? Are not a few fundamental propositions of mechanics what one must fall back upon when a new problem is encountered? And does not the probability of one's seeing new problems and of solving them depend very largely upon one's absolute mastery of those few fundamental propositions? If you agree with me and answer these questions in the affirmative, then it follows, in our opinion at least, that the lines of progress in engineering will depend largely upon the com

plete equipment of our schools and the thoroughness with which the basic doctrines are instilled into the life blood of the students.

It is said of Benjamin Franklin that he could not take a walk nor go on a journey without seeing all about him unsolved problems and new illustrations of universal laws; and with Franklin to see a problem was almost the same as to solve it.

MANUAL TRAINING.

I can not close this rambling address without referring to a recent improvement in secondary education which is likely to affect favorably engineering education, and, through that education promote the future of engineering itself. I refer to the introduction into high schools and academies of the study of tools, materials and the mechanical processes. At the age of fifteen the expanding boy feels the thrill of increasing strength, and a natural hunger and thirst for contact with material things. The instinct to handle things, to do things, requires guidance or it becomes belligerent and destructive. The material universe is to be solved by every one for himself; if in no better way, it will be by pulling things to pieces to see how they are put together; by breaking things to see how strong they are; and by making new things if he only know how.

Then and there are the time and place for manual training; not for a trade or a profession, nor even for fun and pleasure; but for culture and a conscious mastery of tools and materials, and of the arts of construction. During the secondary stage of education the student should find himself and get an intelligent insight into the world of mind and matter around him. Both inborn aptitude and external opportunity should justify the coming engineer. The new educational feature goes far to develop the cne and to discover the other. The fruit of well-organized and logical manual

training is clear thinking, strong, vivid concepts, a world of knowledge gained firsthand, a power and habit of mental analysis of concrete problems-all of which admirably prepare the boy to take up, as a man, the study and practise of engineering. We have all seen something of this rich fruit, and have tested its value. In my judgment, it bodes well for engineering. Like Franklin, these young men (and they are swarming through our manual training schools and knocking in increasing numbers at the doors of our technical schools and colleges) will see things, and solve things, and make things move. The promise of the future is glorious; splendid is the era now dawning; fortunate in their opportunity are the young engineers with clear heads and skilled hands who are coming to the front; and happy are we who, to the best of our ability, are helping on the higher civilization which good engineering makes possible. CALVIN MILTON WOODWARD.

PROBLEMS IN HUMAN ANATOMY.*

FOR the solution of the problems presented to him, the anatomist is by no means limited in his technique to the scalpel or the microscope, but justly claims the right to use every aid to research which other departments of science are able to furnish. His position, therefore, in the scientific field is determined by the standpoint which he occupies and from which he regards animal structures, rather than by any special means and methods employed for their study.

By common consent, anatomical material includes not only structures which may be easily dissected and studied with the unaided eye, but also those which tax the best

* Address prepared for the Section of Human Anatomy at the International Congress of Arts and Science, at St. Louis. Owing to the unavoidable absence of the writer, this address was not delivered.

powers of the microscope for their solution. But even within such wide limits the material that ordinarily comes to hand leaves much to be desired, and in elucidating this or that feature in the structures under examination, it is often found necessary to modify the physiological conditions under which these structures have been working, in the hopes that their appearance may be altered thereby, and so be more readily understood.

Taken in a broad way, this is the reason why the data of pathology and experimental morphology are so important for the development of anatomical thought, helping as they do in the solution of the problems connected with the finer structure of the animal body, just as embryology and teratology illuminate the gross morphological relations in the adult.

I am quite aware that in making the foregoing statements I have suggested more modes of investigation than are at present used in connection with man. But the anatomy of the human body in adult life forms in itself so limited a field that no investigator can possibly confine himself to this portion alone, and there is every reason for here treating the subject in the larger way. As we see from the history of human anatomy, it was brought into the medical curriculum in response to the demands both of physiology and surgery, but gradually became most closely associated with the latter. For a long time its relative significance as a medical discipline was very great, because it represented the only real laboratory work which appeared in the training of the medical student. Indeed, a generation ago the exactness of anatomical methods was so lauded in comparison with the methods then commonly used in medicine, that anatomists came to scoff at the vagueness of their colleagues, while to-day, if we may be persuaded by some of our physiological friends, they

have remained only to prey on the time of students who might be better employed. Although such a thrust may be readily parried, it is, nevertheless, necessary to admit that times are changed, and that as a laboratory exercise human anatomy is today outranked by several of the subjects in which the laboratory work permits a more precise formulation of problems and their more rapid and definite solution. However, it still retains, rightly enough, much of its former eminence.

Among the problems in human anatomy, there is, perhaps, none more important than the way in which it is to be presented to the five young gentlemen ranged around a subject in the somewhat trying atmosphere of the dissecting room. Just what they may be expected to learn from such an experience would require some time to state. Certain it is that these beginning anatomists are almost all of them intending to become physicians, and some of them to become surgeons, and to this end they are building up a picture of the human body which will be useful to them in their profession. They are doing this by the aid of the best pedagogical means at their command, namely, the reinforcement of the ocular impressions by the contact and muscular sensations that come from the actual performance of the dissection itself. If previously they have had some experience in the dissection of the lower mammals, they will note at once the differences shown in the case of man, and if their embryology is at their command, it will be easy for them on suggestion or on their own initiative to appreciate how some of the peculiar relations between parts of the human body have been developed. Beyond this the information obtained is of the same order as that of the vocabulary of a language. The student gets a certain number of discrete pictures of the different parts of the body more or less clearly im