wire, which is broken by the ball leaving the gun. The targets Nos. 2 and 3 consist of frames of common deal wood 6 feet square, across which a copper wire passes backwards and forwards close enough to allow no ball to pass through without breaking it. These frames can be raised to such height as the angle of elevation at which the gun is fired renders necessary. The cylinder A has a screw S cut on its axis, which serves as a means of propelling it while the metallic points draw, so that the lines do not fall upon each other, but run spirally round the cylinder with the pitch of the screw. For that purpose the cylinder with clockwork is fixed to a carriage which runs on the wheels while the lever L and the metallic points at p p p p remain stationary. At the further end is a governor to ensure equal velocity of rotation.

The apparatus is used in the following manner. A galvanic battery is connected with each of the four electro-magnets; one takes into its circuit the pendulum, the second the target at the muzzle of the gun, the third the target at 100 yards distance, the fourth the target at 200 yards; the pen

dulum is then set going, and dots on the cylinder, which is, however, not yet in motion. The clockwork is now set going, and the three points draw lines. After one or two revolutions the command to fire is given, when the ball, in leaving the gun, breaks the wire of No. 1 target, and point No. 1 ceases to draw. When the second target is struck, point No. 2 ceases to draw; and when the third target is struck, point No. 3 ceases to draw. The clockwork

is now stopped. To ascertain the time represented by these lines, the paper is taken off; where point one has ceased to draw is the starting point or zero; the length of the second and third lines will give seconds and fractions of seconds, when compared with the distance of the two dots made by the pendulum, for which purpose a scale may be used, or an ingenious contrivance of Mr. Holmes's, a compass to one leg of which a screw is attached with 100 turns, a nut turns in the second leg and subdivides one turn of the screw into 100 parts. By moving the trammels either way the points of the compass can be made to take in the two dots which represent the second, and each turn of the screw will give the 100th part of the second, be the distance great or small. A second cylinder is provided, which may be prepared with metallic paper beforehand so as to save time. Various objections may be raised to this apparatus, to some of which we will briefly allude. Electricians will point out that after the current is broken residue magnetism in the soft iron will retard the release of the keeper. We have provided against this error, firstly, by making the electro-magnets exactly alike, as mentioned before, so that we have the same retardation in the release of the three different keepers, and this error will thus be neutralized; secondly, by not bringing the keeper into actual contact with the iron, but interposing a thin brass pin. A second objection might be that the different length of the wires might have different, or unequal, effects on the magnets; if this should be the case, resistance coils might be enclosed in the currents to make them all alike. A third source of error, and perhaps the most inconvenient one, is, that when the three points draw, there is more friction than when they are successively released; but as the amount of friction can be ascertained, it can be allowed for. Only by a great number of reliable observations the theory of projection can be elucidated; and General Anstruther would gladly lend the apparatus to any gentleman desirous of its use, expecting only of him to find his own wire, and to make him (General Anstruther) acquainted with the results.*

* The instrument may be inspected at Messrs. Elliott Brothers, 30, Strand.

Thursday, May 30th, 1861.

Captain Sir F. W. E. NICOLSON, Bart., R.N., in the Chair.

ADJOURNED DISCUSSION ON IRON-CASED SHIPS.

The CHAIRMAN. I believe the discussion to be taken to-night is entirely on the hulls of vessels. I have unfortunately myself been absent from the meetings at which Captain Halsted's later papers have been read; but I believe it has been arranged to separate the two subjects of iron plates and hulls in order to avoid confusion in the discussion, and also, I suppose, to induce members who address the meeting to keep their remarks within due limits. I believe that Mr. Grantham has brought a model, the object of which is to show his plan of sheathing iron-ship bottoms with wood and then coppering them.

Mr. GRANTHAM. In addressing the meeting this evening my object is rather to speak generally upon the subject of hulls, and if you would permit me I will speak of the model which is before me merely as an incidental question rather than as a prominent one. I will not occupy many

minutes with the description of that portion of the subject, if you will allow me a few words upon the subject of hulls generally. I believe it to be even of more importance for discussion before the public than that of plates, and I am very glad of this opportunity of saying a few words upon it.

The subject, as you have wisely decided, divides itself into two questions, the armour-plates and the hulls. Upon the question of armour-plates I have always felt that the Admiralty were themselves the best judges, they alone can conduct the experiments on a scale that will be at all satisfactory in giving results; but upon the subject of hulls, we practical men, who have been for a great portion of our lives engaged in watching the progress of iron ships, in designing and building them, may come in and I think afford material assistance to the Government in considering whether the hull itself is to be of iron, or whether the old system is to be continued. Upon the subject of iron hulls I have myself no doubt whatever. Upwards of 30 years' watching their progress has completely satisfied me, that the hulls of all ships will ultimately in this country be built of iron. We have, indeed, many difficulties to contend with, but I know, and I have seen, that these difficulties one by one have given way to the necessities of the case, or to the acknowledged superiority of the material for building ships. It need not be raised as an objection to a system like this that men only adopt it when they are forced into it. We seldom do in this country adopt great improvements without a necessity arising for them. The early adoption of iron ships was entirely from necessity. Men were beginning to navigate rivers and difficult places, and they soon found

that iron was much better, in point of lightness and also in durability, than wooden ships for such purposes; they therefore adopted them not from choice, but from necessity and from competition. Armour-plates themselves of later times have, I think, been adopted from necessity, not from choice. Our neighbours over the water have adopted them, and therefore we felt ourselves compelled to adopt them also. And in the great race of competition which arises, both commercially and politically, though slow to begin in such matters, we generally are soon in the front ranks, and I doubt not that we shall take the lead in this question also; especially as the material and the means of working the material are near at hand.

I have learned out of doors that serious questions have been raised in this room as to the propriety of Government building the hulls of ships of iron. I believe the question of armour-plates is almost by common consent admitted as one that must have its run; but the hulls of ships are still questions in dispute, and I have learned that very strong opinions have been given against the adoption of iron for the hulls of Her Majesty's vessels. Upon this point I wholly differ from the objectors. In the first place, I believe it will be soon felt, and but few years will pass over us before we shall feel it, to have been the most barbarous mistake to clothe ships with 1,000 or 1,500 tons of iron merely for armour, wholly irrespective of any strength which that plating gives to the ship; as it is now, these plates are found to be a great source of straining to the ship, if the ship herself is not exceedingly strong. Now, if we adopt iron hulls, it is quite clear that the combination between the iron hull and the armourplate becomes quite a different story. We shall no longer require those long bolts, which will soon work loose, but we shall have one solid, compact body, one homogeneous mass. Some of the difficulties which have been started in this room, such as they have been reported to me, are, I think, of that nature which have been so often answered, and, in my mind, so satisfactorily answered, that I really would not occupy the short time of this meeting by even referring to the great mass of them; they have been over and over again refuted-they enter into the very history of iron-ship building; and to touch upon them even, would be to bring up again the history of the principle itself, and, therefore, so far as the answering these objections is concerned, I will not venture to do it; I prefer to offer you a few facts and the opinions of men who formerly notoriously opposed iron ships, and who have only come to the conviction that iron hulls must be adopted, from feeling that the fact of their superiority has been so established that they could not resist the conviction which was forced upon them. Now, there is a class of men who, like those gentlemen connected with the navy, have for a long time felt that they could not adopt iron ships; those gentlemen are the great shipowners of the kingdom, who have owned the large mass of sailing ships which go to all parts of the world, carrying the most valuable cargoes. These gentlemen have, as a body, including the under-writers, opposed the introduction of iron ships. It was only the necessity of the case in the adoption of steam, that forced iron ships upon us, and we have for some time made up our minds to have nothing but iron ships for steam purposes. But still these men to whom I refer, too strongly held out in many cases, and I think the opinion of three gentlemen such as I

have described will have some weight with this meeting. They are of the class I have named; none of them own steamboats, they are all sailingship owners; men of great practice in wooden ships, brought up all their lives in the midst of them, no doubt having strong opinions against iron ships. Now, if you will allow me, you will hear what they say: their letters are not very long, but I think they are so strong that I could not answer the objections that have been raised more easily than by referring to those documents; they have been written within this month. The first is by a very large shipowner of this class, a member of the well-known firm of Charles Moore and Co. of Liverpool. Mr. Carlyle writes:

Dear Sir,

Liverpool, 26 April, 1861.

I have your favour of the 20th inst. and in reply have much pleasure in giving our views about iron ships.

We commenced building them in 1852; have built seven, and have two more on the stocks; their tonnage have been from 1,200 to 1,800 tons each, and we have employed them in the East India trade, mostly to Calcutta.

Since first commencing with iron ships we have been fully convinced of their superiority over wooden ones, but for some years we were partly kept back by the prejudices of shippers and underwriters; these have now happily not only been removed, but have been succeeded by a decided preference for iron ships, and this, combined with our own experience of them, has led us to the determination not to build any more wooden ships, but to confine ourselves exclusively to iron. Their advantages are manifold.

They are more durable, not liable to dry rot or worms, require no coppering and caulking, when any damage is sustained you can get at it and repair it locally, without pulling out long shifts of plank; in fact, a comparatively small outlay will keep them in good order.

They are much stronger, and not so liable to strain, indeed they may take the ground, if not rocky, even when loaded, with impunity, where a wooden ship would almost go to pieces, indeed wooden ships seem only capable of sustaining weight when afloat, and almost depend on the pressure of the water for keeping them together.

I may further remark that we have for eight or nine years been using iron lower masts, they are much lighter and stronger than wood, and not more expensive, if required of large size. We consider them very much more durable than wood. We never intend to put a wooden mast into a large ship again; indeed, we are now making our topmasts of iron, and our lower and topmast yards of homogeneous metal.

John Grantham, Esq. C.E. London.

I am, dear Sir,

Your most obedient servant,
ROB. CARLYLE.

The next letter is written by the largest owner, I believe, of iron ships in the kingdom, Mr. William Edward Bates :

My dear Sir,

Liverpool, April 20, 1861.

I have your note. I have twelve iron ships, the largest is I have owned iron ships now for eight years myself, but I have those that have had them for eighteen years.

You cannot, in my opinion, compare iron with wooden ships at all, the difference is so great. For instance, the ship alone named "The Bates Family got on the Pluckington Bank with 3,400 tons of cargo on board from Bombay; she came off with the tide, went into dock, and discharged her cargo in most beautiful order; went into graving dock for examination and painting, was surveyed most minutely, and found not to have injured herself in the slightest. Had she been a wooden ship she would have broken her back in two minutes, as the "Gladiator" did on the same bank about ten months before this time; went into John Laird's graving dock at Birkenhead, and cost the owners and underwriters something like 10,0001. for repairing her.