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shots fired through this lining were with the 2 lb. charge, and were purposely made to strike within a circle of 12 inches' diameter, so that the three holes joined ; still the lining closed over the holes so as to exclude light and to prevent the passage of a thin walking-stick through it where most shattered, which was considered very satisfactory. Of course a great many of the back-plates, about eight, were torn off.

With the small charge of powder the sheathing plate suffers much more than with the full charge, the plate being considerably drawn into the hole, raising the edge inside, and stripping the rivet heads near it. A shot was fired with 1 lb. of powder, which produced the same effect in a greater degree. In all cases the ball carries with it a part of the plate torn from the hole, which increases in size with the strength of the charge.

During the last experiment a splinter from the target struck a sentinel on duty at about 200 yards' distance, passing entirely through the calf of his leg. The piece was about the size of a penny, and must have glanced from the target at a very obtuse angle to have struck the man, who was stationed a little before the line of the target.

A weak shot was passed through the lining of solid indiarubber, which perfectly closed over the hole, excluding water or even air from passing, but causing a great dislocation of the plates at the back, a great number of which had flown off from the nuts breaking in consequence of the pressure thrown upon them by the tenacity of the india-rubber.

Target No. 3 is formed of double half-inch plates riveted together, and no frames. Half is lined with solid india-rubber, not yet experimented with, 8 inches thick, and held on by bolts and square washers as before.

One chief objection to india-rubber as a lining is its expense, costing about 51. per cubic foot. Also it would be difficult to confine it in a warm climate, as it will assume a kind of semifluid motion when acted on by its own gravity (like sealingwax).

The other half of this target is lined with a mixture of indiarubber and cork-dust, 12 inches thick, held on as before. In this case the cork-dust was in too large a proportion to the

india-rubber, and consequently the hole formed by the shot did not close to the same extent, and the lining itself was very much shattered.

Target No. 4 is formed by two thicknesses of half-inch plates with a space of 14 inch between them filled with flannel, flushjointed, single-riveted, no frames. The rivets to hold the flannel are 6 inches square from each other. This has not yet been experimented with.

Target No. 5 is formed of two plates having a space of 10 inches between them, half of this space being filled in with

FIG. 31, TARGET No. 2, 6 FEET SQUARE.

felt, and half with india-rubber and cork-dust introduced in small pieces through hand-holes cut in the ceiling plate between each frame (which are 15 inches apart). The outer sheathing plate is in. thick, and the ceiling in.

The felt proved of no use in stopping the hole, and by its pressure it tore away a large part of the ceiling plate, about

2 square feet, where the ball passed through. This large piece was quite detached from the plate in various fragments, which seem to have broken off quite short.

A similar effect was produced in the ceiling plate by the passage of the shot through the lining of india-rubber and

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cork-dust, and the latter, from being introduced in small pieces, did not close over the hole, and was very much displaced.

Some of the balls made from hot blast iron broke on Target No. 3. The velocity of the ball makes but little difference in the state of the lining after a shot.

APPENDIX VII.

Mr. Clark's Letter descriptive of the injuries sustained by the 'Vanguard' referred to in Lecture X.

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DEAR SIR,-Agreeably to your instructions, I proceeded to Passage to survey the Vanguard' steamer on the 3rd inst., and I herewith send you a rough sketch with a view of conveying a better idea of the position she was in while on the

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rocks, as well as the injuries she has sustained: these could not be well done in letters without it.

Figure 33 is intended to represent the position of the vessel when aground: her bottom appears as if it had rested on a number of hard small rocks, from the stem to the full part of the vessel just under the paddle-wheel; and, from that part to the stern, I have no doubt, was quite unsupported except where the keel was broken 6 feet from the stern-post. I was informed, that while the vessel was on the rocks, she beat very hard, and there can be no doubt of it, for the bottom of the vessel entirely under both the engines and boilers shows it. The plates on both sides of the keel (although half an inch in thickness) are bent upward between the floorings, and in some places the flooring is very much bent and the angleiron is quite separated from them; however, notwithstanding the damage done to the bottom, there is only one hole in it produced by the rocks; and what is likewise very satisfactory, the entire derangement is confined to the hull and the floorings. Fig. 34 is a longitudinal section of the hull to the top of the keelsons, and which are now as perfectly level at the top, the entire length of the vessel, as they were the first day, and so are all the bulkheads above the keelson, although bent, as shown in drawing, below them.

There is one thing I observe in the top sides, that from the

gunwale down to the blue lines all the joinings of the plates are what are commonly called 'jump joints :' this is generally done to make smooth work; in nearly all the upright joints (particularly abaft the engines) they have now the appearance of being wider at the bottom of the joints than at the top, which in my opinion has been produced by beating on the rocks, and particularly from her having no support under that part of the vessel. Lap-joints would be much stronger, and I have no doubt the builders thought so; as all the joints on the bottom under the engines and boilers ale lap-joints.

In my opinion, there is not a stronger instance on record that has afforded more convincing proofs of the superiority of iron over wood than this vessel; and although she was beating hard for so many days, no part of her engine was deranged. Her engines were kept constantly at work, and in my opinion are now in as permanent working order as they ever were. Had the 'Vanguard' been built of wood instead of iron, she could not have been saved.

(Signed)

Your obedient servant,
JOSEPH CLARK.

Note referring to Lecture I.

IN Lecture I., 'On the Necessity of incorporating with the Practice of the Mechanical and Industrial Arts a Knowledge of Practical Science,' I endeavoured to show how neglectful the Government of this country is, in comparison to that of others, in giving its support and encouragement to science and its contributors.

That subject is now under the consideration of the British Association for the Advancement of Science, and in reference to those deficiencies on the part of the Government, as pointed out in the Lecture, I have the satisfaction to submit for consideration the impressions of the Committee, as contained in

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