Kitabı oku: «Memoir of Fleeming Jenkin», sayfa 11

APPENDIX

I. Note on the Contributions of Fleeming Jenkin to Electrical and Engineering Science. By Sir William Thomson, F.R.S., LL. D., etc., etc

In the beginning of the year 1859 my former colleague (the first British University Professor of Engineering), Lewis Gordon, at that time deeply engaged in the then new work of cable making and cable laying, came to Glasgow to see apparatus for testing submarine cables and signalling through them, which I had been preparing for practical use on the first Atlantic cable, and which had actually done service upon it, during the six weeks of its successful working between Valencia and Newfoundland. As soon as he had seen something of what I had in hand, he said to me, ‘I would like to show this to a young man of remarkable ability, at present engaged in our works at Birkenhead.’ Fleeming Jenkin was accordingly telegraphed for, and appeared next morning in Glasgow. He remained for a week, spending the whole day in my class-room and laboratory, and thus pleasantly began our lifelong acquaintance. I was much struck, not only with his brightness and ability, but with his resolution to understand everything spoken of, to see if possible thoroughly through every difficult question, and (no if about this!) to slur over nothing. I soon found that thoroughness of honesty was as strongly engrained in the scientific as in the moral side of his character.

In the first week of our acquaintance, the electric telegraph and, particularly, submarine cables, and the methods, machines, and instruments for laying, testing, and using them, formed naturally the chief subject of our conversations and discussions; as it was in fact the practical object of Jenkin’s visit to me in Glasgow; but not much of the week had passed before I found him remarkably interested in science generally, and full of intelligent eagerness on many particular questions of dynamics and physics. When he returned from Glasgow to Birkenhead a correspondence commenced between us, which was continued without intermission up to the last days of his life. It commenced with a well-sustained fire of letters on each side about the physical qualities of submarine cables, and the practical results attainable in the way of rapid signalling through them. Jenkin used excellently the valuable opportunities for experiment allowed him by Newall, and his partner Lewis Gordon, at their Birkenhead factory. Thus he began definite scientific investigation of the copper resistance of the conductor, and the insulating resistance and specific inductive capacity of its gutta-percha coating, in the factory, in various stages of manufacture; and he was the very first to introduce systematically into practice the grand system of absolute measurement founded in Germany by Gauss and Weber. The immense value of this step, if only in respect to the electric telegraph, is amply appreciated by all who remember or who have read something of the history of submarine telegraphy; but it can scarcely be known generally how much it is due to Jenkin.

Looking to the article ‘Telegraph (Electric)’ in the last volume of the old edition of the ‘Encyclopædia Britannica,’ which was published about the year 1861, we find on record that Jenkin’s measurements in absolute units of the specific resistance of pure gutta-percha, and of the gutta-percha with Chatterton’s compound constituting the insulation of the Red Sea cable of 1859, are given as the only results in the way of absolute measurements of the electric resistance of an insulating material which had then been made. These remarks are prefaced in the ‘Encyclopædia’ article by the following statement: ‘No telegraphic testing ought in future to be accepted in any department of telegraphic business which has not this definite character; although it is only within the last year that convenient instruments for working, in absolute measure, have been introduced at all, and the whole system of absolute measure is still almost unknown to practical electricians.’

A particular result of great importance in respect to testing is referred to as follows in the ‘Encyclopædia’ article: ‘The importance of having results thus stated in absolute measure is illustrated by the circumstance, that the writer has been able at once to compare them, in the manner stated in a preceding paragraph, with his own previous deductions from the testings of the Atlantic cable during its manufacture in 1857, and with Weber’s measurements of the specific resistance of copper.’ It has now become universally adapted – first of all in England; twenty-two years later by Germany, the country of its birth; and by France and Italy, and all the other countries of Europe and America – practically the whole scientific world – at the Electrical Congress in Paris in the years 1882 and 1884.

An important paper of thirty quarto pages published in the ‘Transactions of the Royal Society’ for June 19, 1862, under the title ‘Experimental Researches on the Transmission of Electric Signals through submarine cables, Part I. Laws of Transmission through various lengths of one cable, by Fleeming Jenkin, Esq., communicated by C. Wheatstone, Esq., F.R.S.,’ contains an account of a large part of Jenkin’s experimental work in the Birkenhead factory during the years 1859 and 1860. This paper is called Part I. Part II. alas never appeared, but something that it would have included we can see from the following ominous statement which I find near the end of Part I.: ‘From this value, the electrostatical capacity per unit of length and the specific inductive capacity of the dielectric, could be determined. These points will, however, be more fully treated of in the second part of this paper.’ Jenkin had in fact made a determination at Birkenhead of the specific inductive capacity of gutta-percha, or of the gutta-percha and Chatterton’s compound constituting the insulation of the cable, on which he experimented. This was the very first true measurement of the specific inductive capacity of a dielectric which had been made after the discovery by Faraday of the existence of the property, and his primitive measurement of it for the three substances, glass, shellac, and sulphur; and at the time when Jenkin made his measurements the existence of specific inductive capacity was either unknown, or ignored, or denied, by almost all the scientific authorities of the day.

The original determination of the microfarad, brought out under the auspices of the British Association Committee on Electrical Standards, is due to experimental work by Jenkin, described in a paper, ‘Experiments on Capacity,’ constituting No. IV. of the appendix to the Report presented by the Committee to the Dundee Meeting of 1867. No other determination, so far as I know, of this important element of electric measurement has hitherto been made; and it is no small thing to be proud of in respect to Jenkin’s fame as a scientific and practical electrician that the microfarad which we now all use is his.

The British Association unit of electrical resistance, on which was founded the first practical approximation to absolute measurement on the system of Gauss and Weber, was largely due to Jenkin’s zeal as one of the originators, and persevering energy as a working member, of the first Electrical Standards Committee. The experimental work of first making practical standards, founded on the absolute system, which led to the unit now known as the British Association ohm, was chiefly performed by Clerk Maxwell and Jenkin. The realisation of the great practical benefit which has resulted from the experimental and scientific work of the Committee is certainly in a large measure due to Jenkin’s zeal and perseverance as secretary, and as editor of the volume of Collected Reports of the work of the Committee, which extended over eight years, from 1861 till 1869. The volume of Reports included Jenkin’s Cantor Lectures of January, 1866, ‘On Submarine Telegraphy,’ through which the practical applications of the scientific principles for which he had worked so devotedly for eight years became part of general knowledge in the engineering profession.

Jenkin’s scientific activity continued without abatement to the end. For the last two years of his life he was much occupied with a new mode of electric locomotion, a very remarkable invention of his own, to which he gave the name of ‘Telpherage.’ He persevered with endless ingenuity in carrying out the numerous and difficult mechanical arrangements essential to the project, up to the very last days of his work in life. He had completed almost every detail of the realisation of the system which was recently opened for practical working at Glynde, in Sussex, four months after his death.

His book on ‘Magnetism and Electricity,’ published as one of Longman’s elementary series in 1873, marked a new departure in the exposition of electricity, as the first text-book containing a systematic application of the quantitative methods inaugurated by the British Association Committee on Electrical Standards. In 1883 the seventh edition was published, after there had already appeared two foreign editions, one in Italian and the other in German.

His papers on purely engineering subjects, though not numerous, are interesting and valuable. Amongst these may be mentioned the article ‘Bridges,’ written by him for the ninth edition of the ‘Encyclopædia Britannica,’ and afterwards republished as a separate treatise in 1876; and a paper ‘On the Practical Application of Reciprocal Figures to the Calculation of Strains in Framework,’ read before the Royal Society of Edinburgh, and published in the ‘Transactions’ of that Society in 1869. But perhaps the most important of all is his paper ‘On the Application of Graphic Methods to the Determination of the Efficiency of Machinery,’ read before the Royal Society of Edinburgh, and published in the ‘Transactions,’ vol. xxviii. (1876–78), for which he was awarded the Keith Gold Medal. This paper was a continuation of the subject treated in ‘Reulaux’s Mechanism,’ and, recognising the value of that work, supplied the elements required to constitute from Reulaux’s kinematic system a full machine receiving energy and doing work.

II. Note on the work of Fleeming Jenkin in connection with Sanitary Reform. By Lt. Col. Alexander Fergusson

It was, I believe, during the autumn of 1877 that there came to Fleeming Jenkin the first inkling of an idea, not the least in importance of the many that emanated from that fertile brain, which, with singular rapidity, took root, and under his careful fostering expanded into a scheme the fruits of which have been of the utmost value to his fellow-citizens and others.

The phrase which afterwards suggested itself, and came into use, ‘Healthy houses,’ expresses very happily the drift of this scheme, and the ultimate object that Jenkin had in view.

In the summer of that year there had been much talk, and some newspaper correspondence, on the subject of the unsatisfactory condition of many of the best houses in Edinburgh as regards their sanitary state. One gentleman, for example, drew an appalling picture of a large and expensive house he had bought in the West-end of Edinburgh, fresh from the builder’s hands. To ascertain precisely what was wrong, and the steps to be taken to remedy the evils, the effects of which were but too apparent, obviously demanded the expenditure of much time and careful study on the part of the intelligent proprietor himself and the professional experts he had to call in, and, it is needless to add, much money. There came also, from the poorer parts of the town, the cry that in many cases the houses of our working people were built anyhow that the dictates of a narrow economy suggested to the speculative and irresponsible builder. The horrors of what was called the ‘Sandwich system,’ amongst other evils, were brought to light. It is sufficient to say, generally, that this particular practice of the builder consists in placing in a block of workmen’s houses, to save space and money, the water cisterns of one flat, directly under the sanitary appliances of the other, and so on to the top of a house of several storeys. It is easy to conceive the abominations that must ensue when the leakage of the upper floors begins to penetrate to the drinking water below. The picture was a hideous one, apart from the well-known fact that a whole class of diseases is habitually spread by contaminated water.

In October, 1876, a brisk and interesting discussion had been carried on in the columns of the Times at intervals during the greater part of that month, in which the same subject, that of the health and sewage of towns, had been dealt with by several writers well informed in such matters. Amongst others, Professor Jenkin himself took part, as did Professor G. F. Armstrong, who now occupies the chair of Civil Engineering in Edinburgh. Many of the truths then advanced had been recently discussed at a meeting of the British Association.

It was while such topics were attracting attention that Fleeming Jenkin’s family were shocked by the sad intelligence of the loss that friends of theirs had sustained in the deaths of several of their children from causes that could be traced up to the unsanitary condition of their house. Sympathy took the practical form of an intense desire that something might be done to mitigate the chance of such calamities; and, I am permitted to say, the result of a home-talk on this subject was an earnest appeal to the head of the house to turn his scientific knowledge to account in some way that should make people’s homes more healthy, and their children’s lives more safe. In answer to the call Jenkin turned his thoughts in this direction. And the scheme which I shall endeavour briefly to sketch out was the result.

The obvious remedy for a faulty house is to call in a skilful expert, architect or engineer, who will doubtless point out by means of reports and plans what is wrong, and suggest a remedy; but, as remarked by Professor Jenkin, ‘it has not been the practice for leading engineers to advise individuals about their house arrangements, except where large outlay is in contemplation.’ A point of very considerable importance in such a case as that now supposed.

The problem was to ensure to the great body of the citizens sound professional advice concerning their houses, such as had hitherto been only obtainable at great cost – but ‘with due regard to economical considerations.’

The advantages of co-operation are patent to all. Everyone can understand how, if a sufficient number of persons combine, there are few luxuries or advantages that are not within their reach, for a moderate payment. The advice of a first-rate engineer regarding a dwelling-house was a palpable advantage; but within the reach of comparatively few. One has heard of a winter in Madeira being prescribed as the cure for a poor Infirmary sufferer.

Like most good plans Jenkin’s scheme was simple in the extreme, and consisted in combination and a small subscription.

‘Just,’ he says, ‘as the leading physician of the day may give his services to great numbers of poor patients when these are gathered in a hospital, although he could not practically visit them in their own houses, so the simple fact of a number of clients gathered into a group will enable the leading engineer to give them the benefit of his advice.’

But it was his opinion that only ‘continual supervision could secure the householder from danger due to defects in sanitary appliances.’ He had in his eye a case precisely similar. The following passage in one of his first lectures, afterwards repeated frequently, conveys the essence of Professor Jenkin’s theory, as well as a graceful acknowledgment of the source from which this happy idea was derived: —

‘An analogous case occurred to him,’ he said, ‘in the “Steam Users’ Association,” in Lancashire. So many boilers burst in that district for want of inspection that an association was formed for having the boilers under a continual course of inspection. Let a perfect boiler be bought from a first-rate maker, the owner has then an apparatus as perfect as it is now sought to make the sanitary appliances in his house. But in the course of time the boiler must decay. The prudent proprietor, therefore, joins the Steam-boiler Association, which, from time to time, examines his boiler, and by the tests they apply are able to give an absolute guarantee against accident. This idea of an inspection by an association was due,’ the lecturer continued, ‘to Sir William Fairbairn, under whom he had the honour of serving his apprenticeship.’ ² The steam users were thus absolutely protected from danger; and the same idea it was sought to apply to the sanitary system of a house.

To bring together a sufficient number of persons, to form such a ‘group’ as had been contemplated, was the first step to be taken. No time was lost in taking it. The idea hitherto roughly blocked out was now given a more definite form. The original sketch, as dictated by Jenkin himself, is before me, and I cannot do better than transcribe it, seeing it is short and simple. Several important alterations were afterwards made by himself in consultation with one or two of his Provisional Council; and as experience suggested: —

‘The objects of this Association are twofold.

‘1. By taking advantage of the principle of co-operation, to provide its members at moderate cost with such advice and supervision as shall ensure the proper sanitary condition of their own dwellings.

‘2. By making use of specially qualified officers to support the inhabitants and local authorities in enforcing obedience to the provisions of those laws and by-laws which affect the sanitary condition of the community.

‘It is proposed that an Association with these objects be formed; and that all residents within the municipal boundaries of Edinburgh be eligible as members. That each member of the Association shall subscribe one guinea annually. That in return for the annual subscription each member shall be entitled to the following advantages: —

‘1. A report by the Engineer of the Association on the sanitary condition of his dwelling, with specific recommendations as to the improvement of drainage, ventilation, &c., should this be found necessary.

‘2. The supervision of any alterations in the sanitary fittings of his dwelling which may be carried out by the advice, or with the approval, of the officers of the Association.

‘3. An annual inspection of his premises by the Engineer of the Association, with a report as to their sanitary condition.

‘4. The right, in consideration of a payment of five shillings, of calling on the Engineer, and legal adviser ³ of the Association to inspect and report on the existence of any infraction or supposed infraction of any law affecting the sanitary condition of the community.

‘It is proposed that the Association should be managed by an unpaid Council, to be selected by ballot from among its members.

‘That the following salaried officers be engaged by the Association:

‘1. One or more acting engineers, who should give their services exclusively to the Association.

‘2. A consulting engineer, who should exercise a general supervision, and advise both on the general principles to be followed, and on difficult cases.

‘3. A legal agent, to be engaged on such terms as the Council shall hereafter think fit.

‘4. A permanent secretary.

‘It is also proposed that the officers of the Association should, with the sanction of the Council, have power to take legal proceedings against persons who shall, in their opinion, be guilty of any infraction of sanitary regulations in force throughout the district; and generally it is intended that the Association shall further and promote all undertakings which, in their opinion, are calculated to improve the sanitary condition of Edinburgh and its immediate neighbourhood.

‘In one aspect this Association will be analogous to the Steam Boiler Users’ Association, who co-operate in the employment of skilled inspectors. In a second aspect it will be analogous to the Association for the Prevention of Cruelty to Animals, which assists the community in enforcing obedience to existing laws.’

Towards the end of November, 1877, this paper was handed about among those who were thought most likely, from their position and public spirit, to forward such a scheme, so clearly for the good of the community. Nay more, a systematic ‘canvass’ was set on foot; personal application the most direct was made use of. The thing was new, and its advantages not perfectly obvious to all at a glance. Everyone who knows with what enthusiastic earnestness Jenkin would take hold of, and insist upon, what he felt to be wholesome and right will understand how he persisted, how he patiently explained, and swept away objections that were raised. One could not choose but listen, and understand, and agree.

On the evening of 2nd January, 1878, or, to be more correct, the morning of the 3rd, two old school-fellows of his at the Edinburgh Academy walked home with him from an annual dinner of their ‘Class.’ All the way in glowing language he expounded his views of house inspection, and the protection of health, asking for sympathy. It was most readily given, and they parted from him with pleasant words of banter regarding this vision of his of grafting ‘cleanliness’ upon another quality said to be a growth, in some sort, of this northern land of ours.

But they reckoned hardly sufficiently on the fact that when Jenkin took a thing of this kind in hand it must be; if it lay within the scope of a clear head and boundless energy.

Having secured a nucleus of well-wishers, the next step was to enlist the sympathies of the general public. It was sought to effect this by a series of public lectures. The first of these (one of two) was given on 22nd January under the auspices of the Edinburgh Philosophical Institution. It was apparent to the shrewd lecturer that in bringing before the people a scheme like this, where there was much that was novel, it was necessary first of all that his audience should be aware of the evils to which they were exposed in their own houses, before unfolding a plan for a remedy. The correspondence already referred to as having been carried on in the summer of the previous year had shown how crude were the ideas of many persons well informed, or considered to be so, on this subject. For example, there are few now-a-days who are not aware that a drain, to be safe, must have at intervals along its course openings to the upper air, or that it must be ‘ventilated,’ as the phrase goes. But at the time spoken of there were some who went so far as to question this principle; even to argue against it; calling forth this forcible reply – ’Here is a pretty farce. You pour out a poison and send it off on its way to the sea, and forget that on its way there its very essence will take wings and fly back into your house up the very pipes it but recently ran down.’ A properly ‘trapped’ and ventilated drain was the cure for this.

And the lecturer proceeded to show that in Edinburgh, where for the most part house construction is good and solid, but, as in other towns, the bulk of the houses were built when the arrangements for internal sewerage and water supply were very little understood, many serious errors were made. ‘But,’ the lecturer went on to say, ‘Sanitary Science was now established on a fairly sound basis, and the germ theory, or theory of septic ferments, had explained much which used to be obscure. This theory explained how it was that families might in certain cases live with fair health for many years in the midst of great filth, while the dwellers in large and apparently clean mansions were struck down by fever and diphtheria. The filth which was found compatible with health was always isolated filth, and until the germs of some specific disease were introduced, this dirt was merely injurious, not poisonous. The mansions which were apparently clean and yet fever-visited were found to be those in which arrangements had been made for the removal of offensive matter, which arrangements served also to distribute poison germs from one house to another, from one room to another. These mansions had long suckers extended from one to another through the common sewer. Through these suckers, commonly called “house drains,” they imbibed every taint which any one house in the system could supply. In fact, arrangements were too often made which simply “laid on” poison to bed-rooms just as gas or water was laid on. He had known an intelligent person declare that no harm could come up a certain pipe which ended in a bed-room, because nothing offensive went down. That person had never realised the fact that his pipe joined another pipe, which again joined a sewer, which again whenever there was an epidemic in the neighbourhood, received innumerable poison germs; and that, although nothing more serious than scented soap and water went down, the germs of typhoid fever might any day come up.’

Professor Jenkin then proceeded to show how a house might be absolutely cut off from all contamination from these sources of evil. Then by means of large diagrams he showed the several systems of pipes within a house. One system coloured red showed the pipes that received foul matter. A system marked in blue showed pipes used to ventilate this red system. The essential conditions of safety in the internal fittings of a house – it was inculcated – were that no air to be breathed, no water to be drunk, should ever be contaminated by connection with red or blue systems. Then in yellow were shown the pipes which received dirty water, which was not necessarily foul. Lastly a white system, which under no circumstances must ever touch the ‘red,’ ‘blue,’ or ‘yellow’ systems. Such a diagram recalled the complicated anatomical drawings which illustrate the system of arteries and veins in the human frame. Little wonder, then, that one gentleman remarked, in perplexity, that he had not room in his house for such a mass of pipes; but they were already there, with other pipes besides, all carefully hidden away, as in the human tenement, with the inevitable result – as the preacher of cleanliness and health declared – ‘out of sight, out of mind.’

In plain and forcible language were demonstrated the ills this product of modern life is heir to; and the drastic measures that most of them demand to secure the reputation of a healthy house. Lastly the formation of an Association to carry out the idea (already sketched) cheaply, was briefly introduced.

Next morning, January 23rd, was the moment chosen to lay the scheme formally before the public. In all the Edinburgh newspapers, along with lengthy reports of the lecture, appeared, in form of an advertisement, a statement ⁴ of the scheme and its objects, supported by an imposing array of ‘Provisional Council.’ In due course several of the Scots newspapers and others, such as the Building News, gave leading articles, all of them directing attention to this new thing, as ‘an interesting experiment about to be tried in Edinburgh,’ ‘what promises to be a very useful sanitary movement, now being organised, and an example set that may be worthy of imitation elsewhere,’ and so on.

Several of the writers waxed eloquent on the singular ingenuity of the scheme; the cheap professional advice to its adherents, &c.; and the rare advantages to be gained by means of co-operation and the traditional ‘one pound one.’

The Provisional Council was absolutely representative of the community, and included names more than sufficient to inspire confidence. It included the Lord-Lieutenant of the county, Lord Rosebery; the Lord Justice Clerk, Lord Moncrieff; the Lord Advocate; Sir Robert Christison; several of the Judges of the Court of Session; the Presidents of the Colleges of Physicians, and of Surgeons; many of the Professors of the University; the Bishop of Edinburgh, and the Dean; several of the best known of the Clergy of the Church of Scotland, Established, Free, and of other branches; one or two members of Parliament; more than one lady (who should have been perhaps mentioned earlier on this list) well known for large views and public spirit; several well-known country gentlemen; one or two distinguished civil engineers and architects; and many gentlemen of repute for intelligence and business qualities.

Very soon after the second of the promised lectures, the members of the new Society began to be numbered by hundreds. By the 28th of February, 500 subscribers having been enrolled, they were in a position to hold their first regular meeting under the presidency of Sir Robert Christison, when a permanent Council composed of many of those who had from the first shown an interest in the movement – for example, Professor (now Sir Douglas) Maclagan and Lord Dean of Guild (now Sir James) Gowans, Professor Jenkin himself undertaking the duties of Consulting Engineer – were appointed. And Jenkin was singularly fortunate in securing as Secretary the late Captain Charles Douglas, a worker as earnest as himself. It was the theory of the originator that the Council, composed of leading men not necessarily possessed of engineering knowledge, should ‘give a guarantee to the members that the officials employed should have been carefully selected, and themselves work under supervision. Every householder in this town,’ he adds, ‘knows the names of the gentlemen composing our Council.’

The new Association was a success alike in town and country. Without going far into statistics it will be evident what scope there was, and is, for such operations when it is stated that last year (1885) 60 per cent. of the houses inspected in London and its neighbourhood were found to have foul air escaping direct into them, and 81 per cent. had their sanitary appliances in an unsatisfactory state. Here in Edinburgh things were little, if any, better; as for the country houses, the descriptions of some were simply appalling. As the new Association continued its operations it became the rôle of the Consulting Engineer to note such objections, hypothetical or real, as were raised against the working of his scheme. Some of these were ingenious enough: but all were replied to in order, and satisfactorily resolved. It was shown, for example, that ‘you might have a dinner party in your house on the day of your inspection’; that the Association worked in the utmost harmony with the city authorities, and with the tradesmen usually employed in such business; and that the officials were as ‘confidential’ as regards the infirmities of a house as any physician consulted by a patient. The strength of the engineering staff has been varied from time to time as occasion required; at the moment of writing employment is found in Edinburgh and country districts in various parts of Scotland for five engineers temporarily or permanently engaged.