rapid improvement made abroad in manufactures has subsided; but I hope that you will be all the more ready on that account to listen to a few suggestions as to steps which may be immediately taken to improve the education of those who apply science to practical ends. The subject does not owe its prominence to any events of to-day or of yesterday; it has long been, and will long be, of paramount importance to this country that the education of the producers of wealth should be such as will enable them not merely to compete on advantageous terms with foreigners, but rather to master the great forces of nature by which we work. That we have gained some triumphs can be no reason for relaxing our efforts. With each advance further advance becomes more difficult, and requires more knowledge; the first rude implements and processes employed by man certainly required for their explanation or acquirement no book-learning, but as processes become complex and implements develope into machines, as the occupations of men differ more and more, practice alone is found insufficient to give skill, and study becomes the necessary preparation for all successful work. Our first engineers were not learned men; strong good sense and long practice enabled them to overcome the comparatively simple questions with which they dealt. All honour to those great men; but we who have to deal with more complex, if not with vaster problems, cannot trust to good sense alone, even if we possess it, but must arm ourselves by the study of science and its application to the arts. This being granted, how shall it be done? I need not trouble you by refuting the absurdities of a few men who would have those things taught at schools which have hitherto been taught by practice. What has been taught by practice must still be taught by practice. The business of the school is to teach those things which practice in an art will not teach a man. Let us apply this principle to engineering-the most scientific of all professions. It will be most useless to lecture on filing and chipping; it will be useless to describe the mere forms and arrangements of vast multitudes of machines; one kind of knowledge of the properties of materials can only be acquired, as it always has been acquired, by actually handling them; and the knowledge of the arrangement of a machine is far better learnt by mere inspection than from fifty lectures; moreover, it can be acquired by an intelligent man even if he be wholly unlettered. learning about estimates, the value of goods, methods of superintending work, and dealing with men is foolishness. Written descriptions of puddling a clay embankment, excavating, and such operations, give no knowledge; and yet a vast mass of such knowledge must at some time of his life be acquired by the engineer, and the student cannot be employed as an engineer until he has laid up a store of such knowledge. Colleges cannot give him this; he must serve an apprenticeship in fact if not in form. Young foreigners taught in colleges serve their apprenticeship, at the cost of their employers, during the first few years of their professional life. We call the tyro an apprentice or pupil, and he pays his master instead of being paid by him. I have the strongest feeling against any attempt to substitute collegiate teaching for practical apprenticeship. So far as colleges attempt to teach practice they are and will be a sham in this country and in all others. The work of a college is to teach those sciences which are applied in the arts, but it can go a little further and indicate to its students how the application is made in at least a few selected instances. Applying this dictum to the education of an engineer, his college can teach him mathematics, natural philosophy, chemistry, and geology. No one can doubt that a youth well trained in these branches of knowledge will, even with no further teaching, learn more during his apprenticeship, and during his whole professional life will take a higher standing than the man of equal intelligence untrained in science. College can, however, do more than this; it is found that a lad will go through a considerable number of books of Euclid, and yet see so dimly how his knowledge is to be connected with practice that he may be unable even to compute the area of a field, the dimensions of which are well known to him; and far more is it seen that a man may be fairly grounded in mathematics, and yet have very little idea how to apply his knowledge to mechanical problems. It is the business of those who hold such chairs as mine to point out the connexion between pure science and practice, to show how mathematics are employed in mensuration and in mechanical calculations, to show how the truths of physics are made use of in designing economical machinery, as when we teach the connexion between

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the laws of heat and the steam-engine. The student who has once grasped the fact that there is a real connexion between practice and theory will seldom be at a loss how to find or search for that connexion in after life. The student thus prepared knows what he has to learn from practice, and need not lose precious time in blundering over the numberless scientific problems which practice is sure to suggest but can never solve. The education of the architect, the practical chemist, the manufacturer, and the merchant must be similar, mutatis mutandis, with that of the engineer. Assuming then that the education of those who are to follow more or less scientific pursuits must consist in acquiring, first, that theoretical knowledge which practice cannot give, and, secondly, the practical knowledge which schools should not attempt to give, there remains the question whether the theoretical preparation should be given in special colleges or universities such as our own. I have no hesitation in preferring the university. Mathematics, physics, chemistry, geology, botany, languages, all form elements required in various combinations in the education of all our students. There is but one kind of mathematics, one kind of pure physics, and so forth. Surely it is better that we should teach the men belonging to different professions side by side, so long as the matter taught is to be the same. There are many dangers in an opposite course. There are not a sufficient number of competent teachers to allow of much differentiation. Segregation at an early age is apt to foster professional peculiarities and narrow-mindedness. There is great danger, if physics are to be taught specially to engineers, that a special kind of physics, erroneously supposed to be specially useful to them, will be invented. Lastly, the contact of students and professors of one faculty with the students and professors of other faculties is very beneficial to all. Do not, therefore, cripple old universities by withdrawing from them a portion of their students and their professors, to set up special professional or technical colleges of a novel kind, but rather add by degrees to the power and usefulness of old institutions, and found new colleges and universities after the model of those which are found to have done good work. As an example of what may be safely done, I consider that in Edinburgh we require a chair of architecture and lectureships on navigation and on telegraphy. There is, further, much want of a teacher of mechanical drawing. The professors of physics and chemistry require additional accommodation for practical laboratories, and additional assistance. If these additions were made our college would, in my opinion, meet all the requirements for superior technical education in this part of Scotland. For £2000 per annum all these additions might be made. Notwithstanding the acknowledged importance of education, establishments for giving the higher kinds of instruction are never self-supporting, and students must everywhere be bribed to come and learn. Immediate prizes, in the form of bursaries, scholarships, and fellowships, are required to induce men to cultivate the older fields of learning; and similar bribes are needed to promote the tillage of the more recently colonized domains of applied science. The Whitworth scholarships are a noble example of munificence thus directed, although, in my opinion, the examination requires considerable reform. I hope that further benefits of this kind will be conferred on those colleges which give efficient teaching. Local ambition is most effectually stirred by local prizes; and I regret to find a certain apathy among students here with respect to the Whitworth competition. This appears to arise partly from dissatisfaction with the mode of examination, and partly from the fact that the examiners are men not well known in Scotland. Leaving the question of technical training for the upper classes, and the still larger question of scientific teaching in second-grade schools, the consideration of which would lead us too far a-field, I propose to say a few words on the technical education of the skilled arti

san.

This we must treat on the same principles as have been applied to professional teaching. We must endeavour to prepare the lad in school by teaching him those things which he cannot learn in workshops, but which will enable him to work with greater intelligence while acquiring and applying his practical knowledge. I shall not now speak of that general education which should make him a good man, and which should open to him those great sources of rational enjoyment arising from culture; I will restrict myself entirely to his preparation for becoming an efficient workman. I have in many places said, and I cannot say too often, that the great want of the workman is a knowledge of mechanical drawing. Unfortunately I can

obtain little attention from the general public to this demand for the workman. Very few persons not being engineers know at all what mechanical drawing is. I am sorry to say that some examiners in high places, who direct the education of the country, know very little more than the general public, and teachers who should give bread give chaff. I have lived much abroad, and come into close contact both with English and foreign workmen, and I unhesitatingly say that the chief, if not the only inferiority of Englishmen has been in this one branch of knowledge. I must explain to some of my hearers what mechanical drawing is. It is the art of representing any object so accurately that a skilled workman, upon inspecting the drawing, shall be able to make the object of exactly the materials and dimensions shown without any further verbal or written instruction from the designer. The objects represented may be machines, implements, buildings, utensils, or ornaments. They may be constructed of every material. The drawings may be linear, shaded and coloured, or plain. They must necessarily be drawn to scale; but various geometrical methods may be employed. The name of mechanical drawing is given to one and all those representations the object of which is to enable the thing drawn to be made by a workman. Artistic drawing aims at representing agreeably, and for the sake of the representation something already in existence, or which might exist. Mechanical drawing aims at representing the object, not for the sake of the representation, but in order to facilitate the production of the thing repre

sented.

Now I say that it is this latter kind of drawing that is so vastly important to our artisans, and hence to our wealth-producing population. Very few workmen or men of any class can hope to acquire such excellence in artistic drawing that their productions will give pleasure to themselves and others; but a great number of workmen must acquire some knowledge of the drawings of those things which they produce, and there is not one skilled workman who would not be better qualified by a knowledge of mechanical drawing to do his work with ease to himself and benefit to the public. Mechanical drawing is a rudimentary acquirement of the nature of reading, writing, and arithmetic. In order that a man may understand the illustrated description of a machine he must understand this kind of drawing. To the general public an engineering drawing is as unintelligible as a printed book is to a man who cannot read. The general public can no more put their ideas into such a shape that workmen can carry them out than persons ignorant of writing can convey their meaning on paper. Reading and writing on mechanical or industrial subjects is impossible without some knowledge of the art I am pressing on your attention. This art is taught abroad in every industrial school; a great part of the school time is given up to it. In a Prussian industrial school one third of the whole time is given to it. A French commission on technical education reported that drawing, with all its applications to the different industrial arts, should be considered as the principal means to be employed in technical education. Now, I deliberately state that this subject is not taught at all in England, and that the ignorance of it is so great that I can obtain no attention to my complaints. A hundred times more money is spent by Government to encourage artistic drawing than is given to encourage mechanical drawing, and I say that mechanical drawing is a hundred times more important to us as a nation. Moreover, the little quasi mechanical drawing which is taught is mostly mere geometrical projection, a subject of which real draughtsmen very frequently, and with little loss to themselves, are profoundly ignorant. Descriptive geometry and geometrical projection are nearly useless branches of the art, and the little encouragement which is given is almost monopolized by these. Mechanical drawing proper is confined to those who pick it up by practice in engineering offices. These draughtsmen are often excellent; and on their behoof I claim no other teaching. I speak for the artisan who makes and for him who uses machinery.

There are two ways in which our shortcomings may be remedied: first, the schools of art now established in this country should be enlarged so as to teach real mechanical drawing, and the examinations conducted by the Science and Art Department should be greatly modified; secondly, the drawing which is to be taught in the schools under the superintendence of the new school boards may be, and ought to be, mechanical drawing. Freehand drawing as a branch of primary

education will, I fear, be a useless pastime; but whether that be so or not, I am certain that the accurate and neat representation of the elementary parts of machinery and buildings would be popular with the pupils and could be effectively taught. This kind of drawing educates hand and mind in accuracy, it teaches the students the elements of mensuration and geometry, and it affords considerable scope for taste where taste exists. The chief difficulty will be to obtain competent teachers. I should occupy you too long were I to attempt to show how these must themselves be trained. My chief aim to-day has been to claim attention for a most important and wholly neglected branch of education.

I shall probably be expected to urge the teaching of other natural sciences in our primary schools; nothing, indeed, would give me greater pleasure than to think this could be done. I confess I doubt it; while our second-grade schools are what they are in this respect, and while the Cambridge examination for a degree in applied science is what it is, I dare not think of natural-science classes in our primary schools. I shall be delighted if I am mistaken; but I am certain that mechanical drawing deserves our first attention, as most immediately useful to the artisan and most easily taught. The very books on natural science which are published in England cannot be properly illustrated for want of a sufficient number of competent draughtsmen; and children would be unable to follow the illustrations and diagrams if ignorant of the principles on which they are constructed. I look rather to good reading-books, explained by intelligent masters, as the best manner of teaching the elementary and all-important truths of natural science. No man could do better service than in compiling such reading-books, and there are few wants more urgent than that of masters competent to enlarge upon texts which would thus be put into their hands. The education of our workmen is far more incomplete than that of our professional men. Small additions to existing institutions will meet the want of the latter; but for the former the institutions have to be erected almost from the foundation.

On an Apparatus for working Torpedoes. By PHILIP BRAHAM.

The author of this paper described the various modes of working with torpedoes now extant, and explained their various disadvantages. He then explained his own, which was the propulsion of a torpedo from an invulnerable boat below its water-line by means of the expansion of compressed air. A drawing of the apparatus was exhibited by the author; it consisted of a compression-chamber, in which air could be confined to a great pressure, a tube through which the torpedo could be propelled, and a valve arrangement whereby the progressive velocity of the torpedo could be regulated. By means of machinery driven from the engines that move the ship he proposed to compress air into the compression-chamber to 500 lbs. to the square inch, and when within striking-distance of the vessel attacked the air to be suffered to escape behind the shaft of the torpedo, driving it with considerable force so as to strike the vessel attacked below its water-line and then to explode. By the reaction of the force driving the torpedo forwards, whose average statical pressure would be 85 tons on a diameter of 1-9 shown, the author expects the attacking boat would have its speed considerably diminished, if not entirely neutralized, and so prevent the possibility of collision.

Account of some Experiments upon a "Carr's Disintegrator" at work at Messrs. Gibson and Walker's Flour-mills, Leith. By F. J. BRAMWELL, C.E. Carr's Disintegrator, as is probably well known to most mechanical engineers, consists essentially of two disks, each fixed upon a horizontal shaft. These shafts are placed in one line; the disks which they carry at their ends are separated the one from the other by a space of a few inches. Each disk carries a number of bars or studs disposed in several concentric rings, and standing out at right angles from its face. The concentric rings of studs of the one disk are arranged so as to be in the spaces between the concentric rings of the other disk. The disks are driven in opposite directions, and at a high velocity. The rings of studs, although very

numerous, do not reach to the centre of the machine; this part is unoccupied by studs, and acts as an 66 eye" to receive the feed. The first two or three rings of studs, beginning at the centre, are fixed to one of the disks only, viz. the one opposite to that through which the feed enters, and they serve to distribute that feed equably throughout the machine. So soon as the material has, however, passed by centrifugal force beyond the limit of the outermost of these central or eye rings, it is met by the first of the rings moving in the opposite direction. The studs of this ring find the material while in mid air and moving in a direction opposite to their own motion, and with a velocity due to the circumferential speed of the ring of studs the material has just quitted. The result of this meeting is clearly, first a violent blow, and then a reversal of motion, by which the whole of the material is sent flying through the air in a direction contrary to that which it last had, and with a velocity increased by the increased circumference of the ring of studs which has just put it into motion, a velocity and a direction, however, to be all but instantly arrested and reversed by the action of the next ring of studs, and so the material proceeds from ring to ring until it is delivered, completely pulverized, at the circumference of the machine. It will have been gathered from this description that a Carr's Disintegrator acts to reduce material upon a principle wholly different to those principles upon which millstones, edge-runners, crushing-rolls, rumblers, and stampers act.; in fact, so far as the writer of this paper is aware, upon a principle which had never been applied to a similar or even to an analogous purpose, and that principle is the breaking up of the material by the action of a force which has no other abutment, if the term may be used, than the momentum of the material itself. In fact the material is treated as a shuttlecock, to be bandied backwards and forwards between mechanical battledores, suffering breakage at each blow until it is reduced to the required condition of pulverization.

The proportions of the machine and the size of the spikes or studs are varied to suit the material to be operated upon.

The particular machine upon which the experiments (the subject of this paper) were made is used for converting wheat into flour. It is about 7 feet diameter, and has a space of 10 inches between the faces of the two disks. The disk on the feed side carries six concentric rings of studs, which work between six concentric rings on the opposite disk. This opposite disk has also three "eye"-rings. The studs are circular, half an inch in diameter, and made of crucible steel. The distance from centre to centre of the studs is 2 inches, and from centre to centre of the rings also 2 inches, so that there is a clear space both circumferentially and radially of 2 inches between the studs. The revolving disks are enclosed in a casing, at the bottom of which there is an ordinary creeper or screw to convey away the meal produced; and as now very commonly applied to the cases of millstones, there is an exhaust-pipe connected with an exhaust-fan, to remove the dust and convey it to a depositing chamber, the "stive" room. The machine is driven from a counter shaft by means of two straps, one open, the other crossed, so as to give motion in opposite directions to the two disks. Their ordinary working speed is about 400 revolutions per minute.

By the great courtesy of Messrs. Gibson and Walker, and with the able assistance of their engineer, Mr. Watson, the writer and Mr. Edward Easton were enabled to make the following experiments to test the power required to drive this machine under varying circumstances. In arranging the programme of these experiments, the writer was particularly desirous of ascertaining whether or not a suspicion he entertained as to a source of consumption of power in the working of the machine was justified by the facts. From a consideration of the number of times the disks revolve in a minute, and of the number of rings of studs, it is clear there must be many thousand settings into motion, and reversals of those motions, per minute of any material within the action of the disks; and it occurred to the writer that although the air within the zone of action of the machine weighed only between 30 and 40 ounces, yet even that trifling weight could not be subjected to such treatment without the consumption of a very considerable amount of power. He therefore determined to ascertain the power required, not only when the machine was working in its normal manner, both with and without feed, but also