the question whether we should give more or less protection to our vessels by means of armour plates must be subordinate to the purposes to which the ships are to be applied as floating batteries. I say that you ought, in the first place, to obtain a fast ship and one that will carry her battery so steadily as to make it most useful and effective, and she ought to be able to go through a head sea; then, subordinate to these requisites, protect her as well as you can. It is of no use to have a ship so protected and overweighted that she becomes inefficient as a moveable fort.

Before concluding my remarks on ships I would say a few words on propulsion, upon which subject there is a paper, and in reference to which Dr. Fairbairn has a report to make. You must all be aware that within the last year or two a new mode of propulsion by the emission of water has been introduced, and that the experiment has cost the country about £40,000. It has been broadly asserted that there are no means of obtaining from that mode of propulsion more than 25 per cent. of the power applied. I say, therefore, that before experiments of this sort are tried, the Government, or at all events this Association, ought to investigate the subject in order to see whether the new mode be the most economical application of power or the most wasteful that can be adopted. The matter is not to be worked out by experiments with ships which only go eight knots an hour in smooth water. Admiral Sir Edward Belcher assures me that the speed attained was ten knots, and that she beat the other vessel against which she was tried; to which I would reply that she might easily accomplish that, as the other was one of the worst designed ships in the Navy.

This leads me to another question in which we are all interested, and that is our coast defences. We have all been frightened for some years by the statement that we may be attacked by an invading force, and that we are or have been peculiarly open to the assaults of an enemy, and therefore ought to take the best possible measures for protecting our shores. The theory of this no one can deny, but the mode in which the protection is to be afforded is another thing. I happen to belong to a Volunteer Staff Corps whose especial business it is to consider this question and to advise the Government upon it. The first question we had to consider was the defence of the east coast of England, and especially of the coast of this district. It is obvious that there is no part of our coast which is so vulnerable as this particular division; that there is no part of the country which offers the same inducements to an enemy to attack it as this district. How this district is proposed to be defended, and what are the operations to be undertaken in providing for that defence, are matters of confidence between the corps I represent and Her Majesty's Government; but I have the satisfaction of being able to say that we have come to this conclusion-that, easily as the coast in this district might be attacked, it would by the adoption of judicious means be just as easily defended, and this, too, without the erection of those ponderous forts which have been constructed on the southern coast. But it would have been expected that no sooner were the Armstrong and the Whitworth guns invented, and the power and precision with which projectiles could be fired against any fort or vessel were understood, than the authorities would have turned their serious attention to the question, and would have applied the strictest scientific investigation to the new condition of things. Indeed from the moment when the Armstrong and Whitworth guns were produced the days of embrasures were numbered. Any man who knows anything of the question will agree with me that he is safer in the open country than behind an embrasure. In the open country he affords but one small point of attack, and the chances of his being hit are comparatively small, but beside a gun inside the embrasure of a fort, if a shot strikes within that space he is subject to casualty from splinters. The introduction of the new mode of gunnery marked an epoch at which the whole method of fortification should have been reconsidered; and if this had been done I feel sure that we should not have had to regret the construction of many large useless forts, not however including some of older date, for the design of which it is impossible to discover who is responsible.

A Commission has been instructed to report on the soundness of construction of these forts; I would venture to suggest that another Commission should be appointed to report on their military efficiency.

You have all read the accounts of the vast experiments that have lately been made in gunnery. I believe Dr. Fairbairn has been connected with those experiments on the shields designed for the purpose of resisting the heaviest modern artillery. I will not for a moment deny the value of these experiments; but I must say that, in my opinion, they would have been more valuable if they had been based on the well-known laws of the resistance of metals of the same quality to impact due to weight and velocity. I think that improvement in the structure of guns would have been advanced with more certainty if the action of gunpowder upon the projectile had been clearly ascertained and defined. It is perfectly certain that gunpowder when exploded cannot act with less power than sixty tons upon the square inch; it is also certain that unless that power be immediately reduced we have no gun which it will not destroy; but the fact is that the moment the projectile moves, the enormous expansion of the powder is reduced with such rapidity that the metal has not time to yield and break before the pressure is removed and the danger is gone. This shows that the kind of metal you use, whatever its tenacity and hardness, should be capable of yielding to a certain extent, without absolutely breaking; but it is quite certain that this sort of action is of such a nature that if it be continued to a certain extent it must lead to the destruction of the gun, and that the question as to the life of a gun is only one of how many charges may be fired from it before it is absolutely destroyed. I say that the whole question of the mechanical action of the gunpowder gases should be absolutely determined and settled, and that it ought to be clearly understood by those who are engaged in designing guns. If they go on without this knowledge they are merely proceeding at "hap-hazard," and are groping in the dark.

The improvement of the communication between England and the Continent is now daily exciting more and more attention. Admirably as the service is conducted, under existing circumstances, still the horrois and delays of the middle passage, across the Straits of Dover, will, so long as they continue, restrict free intercourse with the Continent. Indeed, until a traveller can reach his destination, at Paris or Brussels, in the same carriage in which he started from London, this great desideratum cannot be said to have been attained.

There are now two projects, more or less, before the public,-one for bridging the Channel, and the other for tunnelling beneath it. Before analyzing these projects I would make one general observation, viz. that any project involving an outlay (inclusive of interest during progress) of from forty to fifty millions sterling, and requiring from forty to fifty years for its execution, cannot with reason be enter

tained.

With regard to the Bridge project, the latest proposition would appear to be to span the channel by a viaduct consisting of openings of three thousand feet each. The platform must of necessity be upwards of two hundred feet above the level of the sea. The piers would be erected on islets founded in a depth of water of thirty fathoms. Now, bearing in mind that to bridge the Thames in the most economical manner involves a cost of about £125 per lineal foot, and applying this as a standard, contrasting the facilities in the one case with the obvious enormous difficulties and contingencies in the other, the relative cost of the latter must greatly exceed four times that of the former; the minimum cost, therefore, of the channel viaduct cannot be taken at less than £500 per lineal foot, which at once brings the cost up to fifty millions sterling, without taking into account current interest. With these remarks we may dismiss the Bridge question.

A recent article in the 'Times' describes the Tunnel project: the main tunnel is to be constructed at such a depth below the bottom of the channel as, it is hoped, would enable a stratum to be reached which would be impervious to infiltration. Nevertheless there is some uncertainty on this point. It is proposed to commence by driving a trial heading at a cost of two millions sterling. The estimated cost of the main tunnel was stated at, I believe, eight millions, raising the total estimated cost to ten millions. Without going into all the details of construction, I will only allude to the two main features-the driving of the heading, and the completion of the main tunnel.

It is obvious that the heading can only be driven from the two ends; and as

suming that the stratum is found to be so favourable as to admit of an uninterrupted daily progress of two to three yards being made at each face (a rate of progress which is beyond my experience), twenty years will be absorbed in this trial only, and the two millions to be expended will become nearly three millions, by the addition of interest. Assuming the trial heading to be completed, and that arrangements had been made for working the main tunnel from as many as ten faces (four intermediate points and the two ends), and assuming the same absence of contingencies and an unbroken period of peace, a progress of 20 yards per week is the greatest that can be anticipated; but for the purpose of my argument I will assume the progress to be 30 lineal yards per week. Upon this basis an additional period of twenty-five years will be required to complete the main tunnel. By that time the three millions expended in forming the heading will, by the addition of interest, have reached the sum of seven millions, and the eight millions spent in the main tunnel will, for the same reason, have become twelve millions: thus, without taking into account innumerable unforeseen contingencies necessarily attendant on such a work, the outlay may be taken at twenty millions sterling, and the time occupied at not less than forty-five years. The carrying on the tunnel works at four intermediate points through a heading of such enormous length is clearly impracticable; three or four shafts in mid-channel would therefore become essential. Let us consider what the construction of a shaft in mid-channel would involve. It has to be founded in water of the depth of 30 fathoms, then to perforate a water-bearing stratum of uncertain thickness; then let us see what work this shaft has to do. From the very nature of the locality (a sea much vexed by storms) there must be a barrack for the workmen, space for the materials of construction, and a pier for shelter and for discharging the vessels laden with stores and materials. I must therefore confess that, to my mind, although such a work cannot be assumed to be mechanically impossible, it would appear to be commercially and nationally infeasible. If my views are correct, this great international problem still remains for solution.

There is one other subject to which I will allude, and in the presence of so distinguished a man as Mr. Siemens, who has attained so eminent a position as an electrician, and who is now, I am happy to say, engaged in the completion of the Indo-European Telegraph, while he is at the same time applying his great powers to other subjects, I could hardly close my remarks without saying a few words on electricity, with which he has for many years been connected; and it is more especially interesting, as the Electric Telegraph was first practically applied by the late Mr. Robert Stephenson and myself to working the single line of railway, as originally constructed, between this city (Norwich) and Yarmouth, and about the same time it was adapted, at our suggestion, to working the stationary engine system on the Blackwall Railway. The experience derived from these adaptations induced me, at a later period, to originate commercial telegraphy, by establishing the Electric and International Telegraph Company in 1845-46. A question which has been greatly agitated in this country is that of the telegraph to the East, which is undoubtedly an undertaking of extreme utility. There is a company seeking to continue the telegraph to and through Egypt by way of the Red Sea, and they urge the great advantage it would be in making us more independent of foreign influences; but a chain is always estimated by the strength of its weakest link, and there is one weak link in this proposed telegraphic chain, and that is the passage through Egypt. This latter point demands grave consideration. A telegraphic line established via Gibraltar, the Cape of Good Hope, and Ceylon would be 3000 miles longer than the direct route, and would no doubt cost a considerable additional sum; but if such a line were established, the only potentate with whom we should have to contend for possession of that telegraph would be Old Neptune. I wish our friend every success in the operation he is carrying on, but I should be better pleased to see his name associated with the successful completion of an integral line of telegraph to India.

There is another subject to which I would refer, and that is the question of technical education. I think that education of this kind ought to be directed more especially to the branch which the student intends to pursue in after life. You would not give the same education to the engineer that you would give to the

artist or to the agriculturist; but all technical education should be accompanied by a sound knowledge of the elementary laws of mechanics. Indeed I would have this knowledge instilled into the mind of the student over and over again until it became almost a part of his nature; and I make this observation on an experience of five and forty years. I have known some of our greatest engineers and most eminent philosophers make the most discreditable errors through not having been thorougly acquainted with the elementary laws of mechanics, which, I repeat, ought to form the basis of all technical education*. Before any engineer would entrust a young man, however well educated, with any work of the smallest importance, he would require that he should have had some practical acquaintance with the branch to which that work belongs. I think, also, that the theory on which the technical education of the Royal Engineers is conducted ought to be modified, and that they ought to have a certain amount of practical apprenticeship in the great operations they have to carry on; as, for instance, in the construction of forts, and especially before taking charge of gun and other factories. I am well aware that Mr. Whitworth, who has made such a princely endowment for technical education, feels strongly on this point, and he has expressed his conviction that if this principle were adopted vastly greater economy and efficiency for the public service would be attained.

Looking at the achievements of Sir William Armstrong and Mr. Whitworth in revolutionizing the construction of artillery, we have an example of what can be effected by the concentration of the minds of accomplished mechanicians upon special subjects.

In conclusion I may say that, beyond all these things, we should never lose sight of that pursuit to which a powerful Commission has directed its attention-I refer to the application of machinery to the economical working and ventilation of mines; and this being accomplished, the economic use of the products of those mines ought next to engage attention, whether as applied to the working of our manufactories and the turning of our spindles, to cheering the poor man in his humble home, or to propelling through the water those ironclads which represent the might and genius of this great country-the might they may represent, the genius they caricature.

On the Mechanism for utilizing and regulating Convict Labour.
By C. J. APPLEBY.

On R. W. Thomson's Patent Road Steamer. By Professor ARCHER.

An Improved Machine for Drawing-off, Measuring, and Cutting Cloth and other Materials for Manufacturing Purposes. By C. BLYTH.

* As a further illustration of the want of elementary knowledge, I would allude to the Aeronautical Society for promoting aërial locomotion. In this Society are to be found the names of men of considerable scientific and mechanical reputation; but it may be easily shown how vain, in any practical sense, is the pursuit upon which they are engaged.

Let us see what amount of power would be requisite to propel a balloon capable of supporting the weight of one person only.

For this purpose I will assume a perfectly calm atmosphere, also that a gas can be obtained with sufficient tension, but without weight, and that the balloon can be made of a material so light that its weight may also be omitted from the calculation.

With these favourable and impracticable conditions, it would require a balloon of 16 feet diameter to support the weight of a man in our atmosphere.

To propel this at the speed of 20 miles per hour (about one-half of that of an express train) would require an engine of at least five horse-power.

It may, however, be said that a spherical form is not the best adapted for displacing the air; on the other hand, I would observe that this only holds in dead calms that when the course of the balloon is across the current of the atmosphere the resistance would be increased in a much greater ratio.

TRANSACTIONS OF THE SECTIONS.

UNIVESITY

On London Sreet Tramways. By H. BRIGHTO

ORNIN

The author said the London omnibuses were notoriously mismanaged; it was remembered that there were 600 of these vehicles in London, each capable of carrying, on au average, twenty-three passengers, the question became an imThere could be little doubt that a judicious system of street tramportant one. ways, or horse railways, would supply a great and rapidly growing demand, which could not be met by steam locomotion on the ordinary railway, where the trains could not work like omnibuses, taking up passengers at every moment when required, but must run through from station to station. Street tramways had proved a success wherever they had been judiciously tried, andwould doubtless yield an enormous profit if laid down in London and other large towns. They were extensively used in America and Canada, and had been adopted at Copenhagen and the suburbs of Paris; while it was proposed to apply them to Berlin, Brussels, and Vienna. The objection which might be urged against the interference of tramways with the ordinary traffic would be met by taking the many good and available lines afforded by back streets, taking care to bring the line at certain points into close proximity to the main traffic. The system he proposed to adopt was somewhat similar to that which was at present in use in Manchester and Geneva, the vehicle being kept on the track by means of a wheel, which the driver could at pleasure drop into or lift up from a grooved rail in the centre of the track. The formation of the lines for the carriage-wheels was peculiar, there being a slope with a depression of only one inch for each wheel, which would be so made as to fit the wheel-ways, while the depression will be so slight that it could not obstruct the The vehicle would be enabled to turn the progress of any ordinary vehicle. sharpest curves, and would carry forty-eight passengers, exclusive of the driver and conductor. It was proposed, by an efficient system of breaks, with a carefully devised scheme of compensation for the horses, to enable the driver to stop the vehicle at any moment.

On the substitution of Hand-for Shoulder-guns, illustrated by an explanatory exhibition of an Elevator Hand-gun made on the Breech-loading Principle. By E. CHARLESWORTH, F.G.S.

On the Advisability of obtaining a Uniform Wire-Gauge.
By LATIMER CLARK, C.E.

The writer

This was in continuation of a paper on the same subject last year. showed that there were many different gauges now in use, and that it had become almost a usual thing for each manufacturer to set up his own gauge. The evils of this system were obvious, and were much felt by wire-drawers, as well as by engineers. If a gauge were authorized by the British Association, he believed it would be universally adopted by engineers, manufacturers, and wire-drawers. The gauge proposed by the writer differed very little from that now in use, and known as the Birmingham gauge; and he suggested that the question was one upon which the Association might appoint a Committee.

An Improvement in Watering Roads. By W. J. Cooper.

Improvements in the Packing of Boats, Lifeboats, and Pontoons.
By G. FAWCUS.

This was a continuation of a paper read on a former occasion, specially showing how the author's system of packing and stowing of boats was applicable, not only to ordinary ship's boats, but to lifeboats and to pontoons.