mation about works abroad, and deriving experience from their progress and results. Engineering Literature.-Lawyers have been defined as persons who do not possess a knowledge of law, but who know where to find the law which they may require. It may be hoped that a similar definition is not applicable to engineers; but with the rapid increase of engineering literature, it is most desirable that engineers should be able readily to refer to the information on any special subject, or descriptions of any executed works, which may have been published. Much valuable matter, however, is buried in the proceedings of engineering and scientific societies, and in various publications; and often a considerable amount of time is expended in fruitless search. This great waste of time and energy, and the loss of available information involved, led me a few years ago to suggest that a catalogue of engineering literature ought to be made, arranging the lists of publications relating to the several branches under separate headings. There is a possibility that this arduous and costly task may be partially accomplished in separate volumes; and, at any rate, the first step has been effected by the publication, under the auspices of the Paris Inland Navigation Congress of 1892, of a catalogue of the publications on inland navigation. A start has also been made in France, Italy, and England, towards the preparation of a similar catalogue on maritime works, which it may be hoped means will one day be found to publish on the meeting of some future congress. Engineers who have searched, even in the best libraries, for the published information on any special subject, will appreciate what a great boon an engineering subject catalogue would be to the profession, and indirectly to the public at large. The occasional publication of comprehensive books on special branches of engineering, and concise papers on special subjects, by competent authorities, are extremely valuable in advancing and systematising engineering knowledge; but the time and trouble involved in the preparation of such publications must, like the organising of congresses, be regarded as a duty performed in the interests of the profession and science, and not as affording a prospect of any pecuniary benefit. Concluding Remarks. In this address, I have endeavoured, though very imperfectly, to indicate how engineering consists in the application of natural laws and the researches of science for the benefit and advancement of mankind, and to point out that increased knowledge will be constantly needed to keep pace with, and to carry on, the progress that has been made. The great advantages provided by engineering works in facilitating communications and intercourse, and consequently the diffusion of knowledge, in increasing trade, in extending civilisation to remote regions, in multiplying the comforts of life, and affording enlarged possibilities of enjoyment and change of scene, may be regarded as amply acknowledged; but the more gradual and less obvious, though not less important, benefits effected by engineering works are not so fully realised. A comparison of engineering with the other chief branch of applied science, medicine, exhibits some similarities and differences. In both professions, the discoveries of science are utilised on behalf of mankind; but whilst physicians devote themselves mainly to individuals, engineers are concerned in promoting the wellbeing of the community at large. Persons reluctantly consult doctors when they are attacked by disease, or incapacitated by an accident; but they eagerly resort for enjoyment to railways, steamships, mountain tramways, piers, great wheels, and Eiffel towers; and they frequently avail themselves of the means of cheap and easy locomotion to complete their restoration to health by change of air and climate. Physicians try to cure people when they are ill; whereas engineers endeavour, by good water-supply and efficient drainage, to maintain them in health; and in this respect, the evident results of medical skill are far more readily realised than the invisible, though more widespread, preventive benefits of engineering works. Statistics alone can reveal the silent operations of sanitary works; and probably no better evidence could be given of the inestimable value of good water and proper drainage on the health of the population of large towns, when aided by the progress of medical science, than the case of London, where, towards the close of the last century, the death-rate exceeded the birth-rate, and the numbers were only kept up by constant immigrations; whereas now, in spite of the vast increase of the population and the progressive absorption of the adjacent country into the everwidening circle of houses, the number of births exceed the deaths by nearly nine hundred a week. In engineering, as in pure science, it is impossible to stand still; and engineers require to be ever learning, ever seeking, to appreciate more fully the laws of nature and the revelations of science, ever endeavouring to perfect their methods by the light of fresh discoveries, and ever striving to make past experience and a wider knowledge stepping-stones to greater achievements. Engineers have a noble vocation, and should aim at attaining a lofty ideal; and, in the spirit of the celebrated scientific discoverers of the past, such as Galileo, Newton, La Place, Cavendish, Lyell, and Faraday, should regard their profession, not so much as an opportunity of gaining a pecuniary reward, as a means of advancing knowledge, health, and prosperity. The remarkable triumphs of engineering have been due to the patient and longcontinued researches of successive generations of mathematicians, physicists, and other scientific investigators; and it is by the utilisation of these stores of knowledge and experience that engineers have acquired renown. A higher tribute of gratitude should perhaps be paid to the noble band of scientific investigators who, in pursuit of knowledge for its own sake, have rendered possible the achievements of engineering, than to those who have made use of their discoveries for the attainment of practical benefits; but they must both be regarded as co-workers in the promotion of the welfare of mankind. The advancement of science develops the intellectual faculties of nations, and enlarges their range; whilst the resulting progress in engineering increases their material comforts and prosperity. If men of science, by closer intercourse with engineers, could realise more fully the practical capabilities of their researches, and engineers, by a more complete scientific training, could gain a clearer insight into the scientific aspect of their profession, both might be able to co-operate more thoroughly in developing the resources of nature, and in furthering the intellectual and material progress of the human race. The following Papers were read :— 1. Light Railways as an Assistance to Agriculture. By MAJOR-GENERAL WEBBER, C.B., R.E., M.Inst.C.E. The great impetus given to a possible extension of light railways in the United Kingdom through the assembly of representatives of various interests connected with the subject by the Board of Trade in December last has not borne any fruit. To this committee Lieut.-Colonel Addison, R.E., and Mr. Stovin Warburton, our Consul at Rochelle, both made admirable reports on the subject of light railways, the one dealing with Belgium, the other with Western France. The so-called light railways of Ireland, constructed under Government and baronial guarantees, have no analogy either in their engineering or working with the lines with which the author seeks to familiarise the Section. One of the most useful lessons to be learnt from the examples described, both home and foreign, is the ease and safety with which light railways can be worked alongside and on public roads, both in the country and through the towns, even when they are crowded as Ipswich is on a busy day. The author's object in bringing the question before what it is boped may be a Suffolk audience fully acquainted with agriculture is to get up discussion on how far what is practicable will really be remunerative on the capital to be expended, and will lessen the cost of transport between producer and consumer. It has been assumed that in a county such as Suffolk there is use for 200 miles of such light railway, with the suggestion that this length would be distributed in twenty directions, each line having an average length of 10 miles. The gauge throughout to be 24 inches, and the lines to be provided with a turnout alongside of each holding of a certain size, and at each place where an agricultural industry such as dairying is established. Stations, means of warehousing, and workshops to be provided only in the proportion of one to each line, all stopping places to require but trifling expenditure. The rolling stock in proportion to each line to be 2 steam locomotives; 2 composite carriages; 2 timber waggons; 5 covered waggons; 20 goods waggons, of sorts. The total capital cost, if undertaken on such a moderate scale, would be 287,1057., or 1,4367. per mile. The estimate of total takings, allowing one mixed train each ing that one-fourth the capacity for goods is only used, is . £10,300 With 247,200 train lines per annum this gives 18. 6d. a mile. There are many examples to show that the running cost, providing for upkeep and renewals, can be kept within Îs. a mile, leaving a nett profit of The nett receipts for mails, parcel, excursions, and advertising work out at 8,214 £18,514 £6,180 1,782 £7,962 Extra nett revenue would be derived with extra mileage run, and it might be expected that two all-round journeys would before long be necessary on several lines. The author omits the question of the purchase of land. Parliament proposes that the public inquiries preliminary to these light railways shall be essentially local. The views as regards compensation and the necessity of buying land will be governed by considerations which will be local in every respect; and if it is in the interests of the locality generally that their expenditure be kept at a minimum, they need not at most exceed 1007. a mile, or 20,0001. altogether. The burthen of the guarantee of this fund I propose shall be the only one to be taken by the County Council, and when that is realised, I think individual interests will receive no unfair share of consideration. At 4 per cent., including a sinking fund, this may at first throw 8007. a year on the rates, but it will soon be earned. In return, the local authority to have a deferred charge on the earnings, and powers to become sole proprietors at the end of a term of years, and in the meantime to be represented on the board of direction. 2. The Gobert Freezing Process for Shaft-sinking and Tunnelling under Rivers. By A. GOBERT, Ingénieur Civil of Brussels. The process consists in freezing water-bearing strata and running sands by means of liquid ammonia poured straight into the freezing-pipes, which are sunk vertically into the ground which is to be frozen. The liquid ammonia, in passing into gas in the freezing-pipes, produces a more intense cold than that obtained by unfreezable liquids, which are themselves rendered cold by the evaporation of ammonia. By adopting direct evaporation, the danger is avoided of rendering the ground unfreezable in the event of the escape of the unfreezable liquid; the cost of the installation is reduced by dispensing with the unfreezable liquid, and with the apparatus used for rendering it cold; and the power of the refrigerating machine is much better utilised. The process possesses the advantage of being able to freeze the bottom without freezing the upper layers. Thus, when it is necessary to deepen the lined shaft of a mine which has been flooded, the freezing-pipes can be placed inside the lining, without any risk of bursting the lining by the freezing of the water which is inside it. In the case of tunnelling under a river, as the evaporation of the ammonia takes place below the water-level, hardly any of the cold is lost in the contact of the pipes with the water; whereas a great quantity would be lost in employing an unfreezable liquid. 3. East Anglian Coal Exploration, Description of Machinery Employed. By J. VIVIAN. 4. The Effect of Wind, and Atmospheric Pressure on the Tides. In this paper it is shown that while a general rule, founded on observations made by Sir J. W. Lubbock, as to the effect of atmospheric pressure in raising or depressing the height of the tides has been formulated, no attempt has yet been made to deduce any law as to the more important effect of gales of wind; and shows that the subject is one of considerable importance to navigation, especially to pilots and captains of coasting vessels, who frequently have to cross over bars and shoals in navigable channels with a very narrow margin of water under the keel, while tides are frequently raised or depressed to the extent of several feet by gales. In the author's opinion the use of the barometer cannot be made of service in predicting the condition of the tide, as the pressure varies on different parts of the coast, and in order to calculate its effect on the tide the direction of the gradient of pressure and the locality of high and low pressure must first be known. This can only be ascertained by consulting the weather charts issued from the meteorological office. This source of information is not available on board ship or at many of the smaller ports. A rapid alteration in the pressure of the atmosphere is almost always accompanied by wind, which affords a more ready and reliable guide for the immediate purposes of navigation. From an analysis of two years' tides at the Port of Boston, and excluding occasions when the element of wind would affect the case, the author found that out of 152 observations, 61 gave an opposite result to that which would have been expected; a high barometer frequently being accompanied by a high tide, and a low barometer by a low tide. On the other hand, with few exceptions, it is found by experience that when the wind blows with any force along a coast in the same direction as the main stream of the flood tide, the tides at all the ports along that coast will be higher than the calculated height given in the tide tables; and when the wind blows against the flood tide, high water will be lower than calculated. The author gives numerous instances of the effect of gales in raising and lowering the natural height of the tides, and tables showing the effect of the gales of November 1893 and 1894 on the tides at the principal ports round the coast of Great Britain. These figures show that the variation is on some occasions as much as from 5 to 6 feet, and the difference in the height between two succeeding tides as much as 8 feet. From an analysis of the register of tides at Boston Dock on the East coast over two years, the author found that 24 per cent. of the whole tides recorded were sufficiently affected by the wind as to vary 6 inches from the calculated height; thirty varied by 2 feet, seven by 3 feet, six by 3 feet, three by 4 feet, two by 4 feet, one by over 5 feet, and one by 6 feet 3 inches. From these tides, checked by comparison with those at other parts of the coast, the author has formulated a table showing the amount to be added to or deducted from the height of the tide of the day as given in the tide tables, according to the strength and direction of the wind: Approximately it may be taken that with a given force of wind of 3 on the Beaufort scale a tide will be raised or depressed by half an inch for every foot of range; with a force of from 4 to 6 the variation may be expected to be 1 inch for every foot; with a gale of from 7 to 8, 1 inch; and if the gale increases to 10, then 2 inches. For example, supposing the rise of a Spring tide at any particular port to be 16 feet above low water, and the wind to be blowing with a force of 5, then 16 multiplied by one inch would make that tide 16 inches higher, or 17 feet 4 inches. It is not intended that any absolute reliance can be placed on the formula, but that it may be taken as a sufficiently approximate guide by which pilots or captains of coasting vessels may be able to form some estimate as to the extent to which the tide will be affected, and consequently the depth of water available over bars or shoals. FRIDAY, SEPTEMBER 13. The following Papers were read :— 1. Notes on Autumn Floods of 1894. 2. On Weirs in Rivers. By R. C. NAPIER, and F. G. M. STONEY. 3. An Experiment in Organ-blowing. By W. ANDERSON, C.B., D.C.L., F.R.S. An organ of sixty-one stops and four manuals at the Goldsmiths' Technical and Recreation Institute, New Cross, London, was found defective in its blowing apparatus. Sir Frederick Bramwell, Bart., LL.D., F.R.S., and the author, governors of the Institute, were requested to look into the matter, and finding that the maximum pressure required was only 10 inches of water, determined to adopt an ordinary smiths' fan, driven by an electric motor specially wound and coupled direct to the fan spindle. Some preliminary experiments showed that a fan with a 10-inch outlet and a six bladed 25-inch impeller, driven at about 1,900 revolutions per minute, was amply competent to give the pressure and volume of wind required. Some apprehension was felt lest the pulses due to the fan might interfere with the lower notes of the organ, but exhaustive trials have shown that no such interference takes place. 4. The Growth of the Port of Harwich. By W. BIRT. 5. The new Outlet of the River Maas at the Hook of Holland, and the Improvement of the Scheur Branch up to Rotterdam. By L. F. VERNON HARCOURT, M.A., M.Inst.C.E. The gradual shoaling of the mouths of the Maas, coupled with the increasing draught given to sea-going vessels, rendered the access to Rotterdam inadequate in the first half of this century. An attempt was made to obtain a deeper entrance |