Miscellaneous Papers on Mechanical Subjects/Address delivered to the Institution of Mechanical Engineers
ADDRESS TO THE INSTITUTION OF
MECHANICAL ENGINEERS.
Delivered at Glasgow, 1856.
Gentlemen,—This being the first time I have taken the chair since you did me the honour to elect me your President for the present year, I propose to address you shortly on a few topics more or less connected with our profession of mechanical engineering. But first, let me express my gratification, and I am sure that of my fellow-countrymen, in thus meeting our northern friends in this important city.
Glasgow is peculiarly interested in the mechanical arts, for the minerals for making iron are found in great abundance in this locality; indeed, it is to this neighbourhood, more than to any other, that the world is indebted for the cheapest and most abundant supply of iron. Here, too, that metal is converted into a great variety of machinery. There are large manufactories of the steam-engine—fixed, marine, and locomotive. Cotton, manufacturing, and various other kinds of machinery are also made here in considerable quantities. With such links of connection amongst us, I trust that this, our first meeting in this city, may be the forerunner of many others, and that we shall add many members to our Institution.
Great attention is now being paid to improvements in the manufacture of malleable iron and steel. I need not tell you of what vast importance it must be to those who are more immediately connected with those branches of mechanics requiring nicety of workmanship, to have iron and steel of a better quality. I may mention that in making rifle-barrels for the experiments which I have undertaken for the Government, one of the greatest difficulties I encounter, in attaining the degree of accuracy that I require, arises from the defects in the metal. What we want is iron of great strength, free from seams, flaws, and hard places. Inferior iron (with the use of other defective and improper materials) is perhaps the main cause of one of the greatest errors committed in the construction of whatever in mechanism has to be kept in motion. I mean the increase of size of the parts of a machine or carriage, in order to get strength, thereby adding weight until they are considered to be strong enough. In our vehicles of draught and carriages this is strikingly the case, Now this ought not to be. Lightness is the thing to aim at, and safety should be sought in the elasticity, form, and good quality of the material. Should a carriage be found to twist and get out of form, that would be a proof of its being too light. But to prevent a carriage breaking down by increasing the size of its parts, and thereby adding weight, instead of improving quality, is mechanically wrong. Indeed, it is quite distressing to see the enormous weight of our carriages, particularly those drawn by animal power. It should be an axiom in mechanics that whatever has motion should be as light as circumstances will admit; this applies equally, whatever the source of power may be, whether the motion is produced by human, horse, or steam power.
I would next call your special attention to the vast importance of attending to the two great elements in constructive mechanics—namely, a true plane and the power of measurement. The latter cannot be attained without the former, which is therefore of primary importance; and its accomplishment is so easy and so simple as to leave without excuse any establishment neglecting to secure it. It is necessary to make three planes in order to obtain a perfect one, and cast iron is the best material generally to use. Whatever the size of the plane required, the tripod form is absolutely essential for its support; and the strengthening ribs must be placed with reference to the supports. I cannot impress too strongly on the members of the Institution, and upon all in any way connected with mechanism, the vast importance of possessing a true plane, as a standard for reference. All excellence in workmanship depends upon it. I may mention that it was at the meeting of the British Association held in Glasgow in 1840 that I read a paper on the mode of producing a true plane, to which I would refer those desiring information on the subject.[1]
Next in importance to a true plane is the power of measurement. I have brought with me, for your inspection at the close of the meeting, a small machine, by which a difference in length of the one-millionth part of an inch is at once detected. The principle is that of employing the sense of touch, instead of sight. If any object be placed between two parallel true planes, adjusted so that the hand can just feel them in contact, you will find, on moving the planes only the 50-thousandth of an inch nearer together, that the object is distinctly tighter, requiring greater force to move it between them. In the machine before you, the object to be measured is the standard inch, in the form of a small square bar, both ends being true planes; and in this case, in order to measure with the utmost accuracy, a thin flat piece or bar is introduced, having its two sides made also perfect planes. This is placed between the inch bar to be measured and one of the end surfaces of the machine. This thin bar, which I name the gravity piece, is brought into contact with the two planes, so as just to allow it, on being raised, to fall by its gravity; and you will find that, by bringing the planes into closer contact by even the one-millionth of an inch, the gravity piece will be suspended, friction overcoming its gravity. This machine and a larger one, are used for making standards of length. When the standard yard, which is a square bar of steel, is placed in the larger machine, and the gravity piece adjusted so as just to fall by its weight, the heat imparted from the slightest touch of the finger instantly prevents its fall, thus showing the lengthening of the bar by so small an amount of heat as that I have indicated. We have therefore in this mode of measurement all the accuracy we can desire; and we find in practice in the workshop that it is easier to work to the ten-thousandth of an inch from standards of end measure, than to the one-hundredth of an inch from the lines on a two-foot rule. In all cases of fitting, end measures of length should be used, instead of lines.
The question of correct measurement is in immediate connexion with another, which will repay all the attention that can be given to it, and I think there is no subject that can be more profitably discussed amongst us;—I mean that of proper gradations of size in all the various branches of the mechanical arts. I think no estimate can be formed of our national loss from the over-multiplication of sizes. Take for instance the various sizes of steam-engines—stationary, marine, and locomotive. In the case of marine engines, the number of sizes up to 100 horse-power will probably not be short of thirty, where ten perhaps would be ample. If so, look at the sums expended in patterns, designs, and in the number of tools for their manufacture. Nor is this all; for if there were only ten sizes instead of thirty, there would be three times the number made of each pattern; and, as you know, the very soul of manufacture is repetition. By attention to this, the ship-owner would be benefited by getting a better engine at a less price. In the case of locomotives and carriages, I would urge the subject on the attention of our members, the engineers of the great lines of railway—the London and North-Western, the Midland, the Great Northern, for instance. I hope they will permit me to suggest that they should consider and determine not only the fewest possible number of sizes of engines and carriages that will suffice, but also how every single piece may have strictly defined dimensions. This question is also well worthy the attention of our architects and builders. Suppose, for instance, that the principal windows and doors of our houses were made only of three or four different sizes. Then we should have a manufactory start up for making doors, without reference to any particular house or builder. They would be kept in stock, and made with the best machinery and contrivances for that particular branch; consequently, we should have better doors and windows at the least possible cost. Our friends across the Atlantic manage matters in connexion with their buildings much better than at present we do.
I hope the members of this Institution will join me in doing what we can with reference to those two important subjects—correct measurement, and its corollary, proper gradations of size. The want of more correct measurement seems to prevade everything. Take, for instance, the case of the common brick, which ought to be three inches thick. Who is there that has made an addition to a building who has not felt inconvenience from the irregularity of size?—the new brick being, perhaps, too thick, and so not allowing sufficient mortar to be used; or too thin, and requiring too much mortar.
Perhaps one of the most effectual means that could be adopted, in the first instance, to remedy this unsatisfactory state of things, would be for the Government to supply corporate bodies with proper standards of length—such as the inch, the foot, and the yard. The corporate bodies themselves might then have their own standards of size, founded on these, and made to suit the particular wants of the different trades in the locality. The only standard of length at present supplied by the Government and kept by the corporate bodies is the standard yard; but there is so little attention paid to accuracy, that to the engineer and machinist it is not of the slightest use, and is only employed to adjust yard sticks for measuring woven goods.
There is also another subject which bears upon this question, and which has lately been before the Legislature—that of decimalising weights and measures. There can be no doubt of the beneficial results that would follow the passing of such a measure. There may be a difference of opinion as to what the unit or integer of lineal measure should be; but I think that it should be the inch, for, from the accuracy with which we can now measure that length, there would be no difficulty in determining and fixing the length of its multiples. The most important divisions of length in mechanism are those of parts of an inch, and if the length of the inch were altered it would cause much confusion. Small accurate standards of length, of the decimal parts of an inch, would be of much service to some trades. There is now no standard of appeal; and the different wire and other gauges differ so considerably, that the manufacturer, in the case of small wire and sheets of metal, has to send a sample of what he wants, there being no means of correctly expressing its size.
Although I have said so much to you with reference to the desirableness of further improvement and greater perfection in the mechanical arts, I congratulate you on the success which in our time they have attained, and the high consideration in which they are held. Inventors are not now persecuted, as formerly, by those who fancy that their inventions and discoveries are prejudicial to the general interests, and calculated to deprive labour of its fair reward. Some of us are old enough to remember the hostility manifested to the working of the power-loom, the self-acting mule, the machinery for shearing woollen cloth, the thrashing machine, and many others. Now, the introduction of the reaping and mowing machine, and other improved agricultural machinery, is not opposed. Indeed, it must be obvious to reflecting minds that the increased luxuries and comforts which all, more or less, enjoy are derived from the numerous recent mechanical appliances and the production of our manufactories. That of our cotton has increased during the last few years in a wonderful degree. In 1824, a gentleman with whom I am acquainted sold on one occasion one hundred thousand pieces of 74 reed printing cloth at 30s. 6d. per piece of 29 yards long; the same description of cloth he sold last week at 3s. 9d. One of the most striking instances I know of the vast superiority of machinery over simple instruments used by the hand is in the manufacture of lace, where one man with a machine does the work of 8,000 lacemakers on the cushion. In spinning fine numbers of yarn, a workman on a self-acting mule will do the work of 3,000 hand-spinners with the distaff and spindle; and there are other striking facts of a similar kind mentioned in my Report on the New York Industrial Exhibition.[2]
Comparatively few persons, perhaps, are aware of the increase of production during our lifetime. Thirty years ago, the cost of labour for making a surface of cast iron true, by chipping and filing by the hand, was 12s. per square foot; the same work is now done by the planing machine at a cost for labour of less than 1d. per square foot, and this, as you know, is one of the most important operations in mechanics. It is therefore well adapted to illustrate what our progress has been. At the same time that this increased production is taking place, the fixed capital of the country is, as a necessary consequence, augmented; for, in the case I have mentioned of chipping and filing by the hand, when the cost of labour was 12s. per foot, the capital required for tools for one workman was only a few shillings; but now the labour being lowered to 1d. per foot, a capital in planing machines for the workmen is required, which often amounts to £500, and in some cases more. This large outlay of capital, invested in machinery to increase production, makes it very difficult to curtail the hours of working machinery, as much as could be desired. In some cases two sets of work-people have been employed in relays, each working eight hours a day; and this system perhaps may in time be extended, although it is attended with certain inconveniences. If, however, the relay system could be so improved and organised as to allow more time for the better education of young operatives, none would more cordially rejoice than myself. I believe that the science of mechanics, though a mere material power in itself, may, if rightly used, become a moral lever, by which, like Archimedes of old, we may seek to raise the world.
There is at the present time a very gratifying circumstance in connection with the extension of machinery; namely, the large remuneration which operatives who work machines actually receive compared with those who perform hand labour without the help of machinery. I would here mention, with reference to the amount of wages paid to the operative, that it does not depend solely on the master manufacturers of this country, but is governed in some measure by what is paid by the manufacturers of other countries who are in competition with our own. When I was in America in 1853, I found that the American operatives received somewhat more wages than are paid in this country; but they worked much longer hours, although the climate, during some parts of the year, is so unfavourable. These longer hours enable the American manufacturer to turn over his capital more frequently.
This question of increased production, with which we, as mechanical engineers, are so identified, is so entirely dependent upon the power of the people to consume, that I hope I shall be excused in adverting to it. Our yearly exports now amount to about a hundred millions sterling, having doubled in a short time, while our home productions have been greatly increased from the same cause, namely, the increased ability of our people to consume. As a general principle it would seem to be far better to levy a small impost on the entire wealth of an individual rather than to fasten a tax on particular objects, which if produced would constitute wealth, but which are not made because of the threatened impost. The remaining duty on carriages seems to me to be one of this description. Were there no tax, almost every one who keeps one carriage would keep more, while large numbers would have one who now have none. By their use locomotion would be increased threefold, and hence much valuable time would be saved. Besides, a large number of the best description of artisans would be called into existence for their manufacture—a class, too, who are well able to turn their hand, in cases of necessity, to other employment. If, therefore, it is desirable for a nation to possess wealth in carriages, it is a mistake for legislation to prevent it.
Formerly, when the wealth of a nation was produced, as it were, by hand labour, a different state of things existed to that of the present day. As I have shown, our means of production are now increased in some cases more than a hundred and in others more than a thousand fold; and this will go on, just in proportion as the masses of our people are able to consume larger quantities of everything that they require. When the farm labourer pays less for his sugar and tea, more meat will be consumed (which again goes to improve the land); also more wool for our manufactures.
In this wonderful power of producing wealth which now exists, none can be more interested and benefited than the proprietors of the land. A striking proof of this is given by its increased value in the manufacturing counties, and for miles adjoining our manufacturing towns. The competition, too, of our manufacturers and merchants to become possessors of land is shown by the small rate of interest with which they are satisfied, for the outlay of their capital on the soil. The proprietors of land may rest assured that, in the future development of mechanical improvements, none will be more benefited than themselves. I do not hesitate to say that all harvest operations on land, properly laid down, will very shortly be performed in one-fourth the time required with the hand labour now expended, by the farther application of machines worked by horse-power. This is my conviction, based upon the experience I have had in the successful working of the machine I constructed for sweeping the streets, and at the same time filling the cart, by horse-power. By the combined aid of mechanical improvements and the science of chemistry, together with the greater skill of our modern agriculturists, the culture of the land throughout Great Britain must more and more approximate to that of a garden.
We have seen the effect of the repeal of the duties on glass and bricks, in the improved appearance and reduced cost of residences, and a still further benefit may be expected to result from the removal of the remaining duty on timber. While, therefore, we congratulate ourselves on the great results which the mechanical arts have achieved, we have every reason to be thankful that our legislators have removed so many impediments to our progress. The glorious fruits of the legislative labours of that great and good man, Sir R. Peel, may give us hope that the time is not far distant when all remaining obstacles of this kind will be swept away. When that period has arrived, and when the industry of this country has been systematised upon sound principles of economical science, and in each department carried nearer to those standards which, in the case of mechanics, I have endeavoured to indicate, we shall have less reason than at present to doubt the stability of our manufacturing pre-eminence.