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to its fracture. It was urged that the great
weight and fall given to the hammer must have
acted prejudicially. These were supposed to be
rendered necessary by the thickness of the metal,
which had been made considerable, in order to
guard against accident; but it was contended that
it had a contrary tendency.

ROYAL GEOGRAPHICAL SOCIETY.

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uninhabited shore of King William Island, be neath the snow; but as it was most carefully examined three times over, he could not think that any conspicuous object, such as would be put up to indicate where records were deposited, could possibly have escaped them. The summer at Port Kennedy proved a warm one, yet the ice did not permit them to move until the 9th of August, and the object of the expedition having been attained, they commenced their homeward voyage.

bell, for the convenience of sounding, &c. The second large bell weighed upwards of 13 tons, and was cast by Messrs. Mears, at Whitechapel. The best method for raising this bell in a safe and economical manner having been carefully considered, it was decided to use a treble-purchase crab, with large blocks and a fall. A new chain, made by Messrs. Hawks, Crawshay, & Co., 1,500 feet in length, and tested to a strain of 10 tons, was employed. This chain, when reeved through ON Monday night, at one of the largest meettwo three-sheave blocks, and with a standing ings, perhaps, ever held of the Royal Geographical Sir Roderick Murchison said (among other chain, gave a power equal to about 70 tons. As Society, Captain M'Clintock, the distinguished things), to geographical science the results of the bell was 9 feet in diameter at the sound bow, Arctic navigator, read a memoir of his voyage on Captain M'Clintock's expedition were little less and 7 feet 10 inches in height, and the dimen- board the Fox in search of the survivors of the than glorious, for, among others, it had detersions of the tower were only 8 feet 6 inches by 11 expedition of Sir John Franklin. The meeting, mined for the first time the navigability of Bellot feet 1 inch, it was not possible to lift it by the convened at half-past 8 o'clock, and at which Sir Strait, and the northernmest part of the American crown, with the mouth downwards. Consequently, Roderick Murchison presided, was held in Burling-continent. In the forthcoming narrative (to be a cradle had to be constructed in which the bell ton-house, Piccadilly. published shortly by Captain M'Clintock) the diffishould rest on its side. Friction rollers were Captain M'Clintock, who was cheered on present-culties which those gallant men had surmounted attached to the cradle at the top and at the bottom, ing himself to the meeting, read his memoir of the would be presented to the world in detail. The which served us guides, and rubbed against balks incidents and results of his voyage, which, in point very first incident of their voyage in a little yacht of timber set upright in the shaft. The upper of fact, embodied the more interesting portions of of only 170 tons was that when they had nearly block was made fast, by a shackle and clip, to a his dispatches to the Admiralty published the day reached Baffin-bay they were drifted back 1,200 flitch beam formed of two plates of iron fixed after his return to this country, and which are geographical miles into the Atlantic again. But between six timbers; and the lower block was still so fresh in the public recollection as to render they returned to the charge, and eventually sucfirmly secured to the cradle by massive bolts and a repetition of them unnecessary. At its conclusion, ceeded for the first time in revealing the fate of straps. The treble-purchase crab was fixed to a however, he said there were two important ques- the illustrious Franklin and his associates. There strong staging in the cast-iron lantern at the top tions which had been so frequently asked him that was no doubt that Franklin went further to the of the tower, in such a position as to leave a he gladly availed himself of that opportunity of north in a ship than any British seaman-he distance of about 19 feet between the bottom of offering some explanation upon so deeply interest- (Sir R. Murchison) was speaking of the search the crab and the crown of the bell, when the latter ing a subject. The first question was, whether made in Wellington Channel, and theu he rewas raised to its proper position. As the single some of the 105 survivors might not be living turned, and performed that extraordinary voyage barrel of the crab could not take up all the chain among the Esquimaux? The various families or round Cornwallis Island, by which, in the first without incurring the risk of surging, consequent communities of Esquimaux met with by Rac, year of his enterprise, he proved it to be an upon the coiling of the chain in so many thick- Anderson, and himself, at different times and island. nesses, several lifts were made, as stated in a places, all agreed in saying, “No, they all died.” tabular statement given in an appendix, in which The western shore of King William Island, along was also recorded the time occupied for each lift, which they were compelled to travel for two-thirds and the fleeting of the chain. An iron chain-stop- of their route, was uninhabited, and all that was per of special construction was made for the pur- known of the mouth of the Back River was pose of holding the chain during the fleeting on derived from the journeys of Back, Simpson, the drum of the crab. The weight of the bell Anderson, and himself. None of them had met and the cradle and iron work, together with the natives there, consequently it was fair to conclude chain, blocks, &c., was about 25 tons, exclusive of that the Esquimaux but seldom resorted to so friction. The process of raising commenced at six inhospitable a locality. In fact, their life was o'clock in the morning, and continued without spent in a struggle for existence, and depended intermission, until noon on the following day, mainly upon their skill in taking seals during the when the bell was safely landed on a staging in long winter-a matter which required such long the clock room. The cradle was then disconnected, training that no European had ever yet succeeded and the bell was turned over with the crown up. in acquiring it. His (Captain M'Clintock's) two wards. An eye-bolt was passed through, and Greenland Esquimaux tried various methods at being now clear of the shaft, the bell was lifted in Bellot Strait, yet did not succeed; and without the usual way from the clock room to the bell dogs trained to scent out the small breathing chamber. The total height the bell was raised holes of the seals through the ice, and through the was 201 feet 3 inches, at an average velocity of snow which overlays the ice and conceals them abo at 6 feet 5 inches per hour. The paper then from observation, he did not think that even the proceeded to state the experiments that had been Boothian Esquimaux could live. It required not ma.de before the weight of the hammer and the only that a man should possess a trained dog, but di stance it should fall through were finally settled. that he himself should be so well trained in the The weight was decided to be 6 cwt. 3 qrs. 10 lbs., only successful mode of seal hunting in this with a fall of 13 inches. This arrangement for locality in order to subsist. It was therefore striking the hours was continued until the bell evidently an error to suppose that where an was discovered to be fractured in two places. One Esquimaux could live a civilized man could live of the cracks was precisely in the same position in there also. Esquimaux habits were so entirely this bell as in the former one, exactly opposite to the different from those of other people that he place where it was struck by the hammer, and the believed there was no instance on record of either other was about two feet away from it. The first a white man or an Indian becoming domesticated fracture appeared to be about 15 inches and the among them or acquiring tolerable expertness in second about 24 inches long; but they did not ex- the management of a kayak. With regard to the tend through the thickness of the metal, nor with- probability of procuring the means of subsistence in 2 or 3 inches of the lip at present. The whole independently of the Esquimaux, he stated what of the works for raising the bell were carried out was shot by his own sledge party-and they never by Mr. Hart, assistant to Mr. James, under the lost a chance of shooting anything-during the superintendence of Mr. Quarm, Clerk of the Works journey along the lands in question, which at the New Palace. occupied them for 79 days and covered nearly 1,000 geographical miles of distance. The sum total amounted to two reindeer, one hare, 17 willow grouse, and three gulls. The second question was, why had the remains of so few of our lost countrymen been found? It was indeed true that only three of the 105 were discovered, but it was to be borne in mind that from the time they left their ships they were dragging sledges and boats, and therefore they must have travelled almost constantly upon the ice-not upon the land-consequently all traces or remains there vanished with the summer thaw of 1848. There was no doubt that many relics still remained strewed along the

In the discussion, it was remarked, that the composition of the metal of the bell was not the same as that usually adopted in this country and on the Continent, there being a greater proportion of tin than was customary. It was also thought that the use of charcoal-smelted copper, as was the case in Russia, was advantageous. It was suggested whether the interval between the blows of the hammer might not have been too short, and whether the chattering of the hammer, due to its not being cleared immediately after striking, might not have a tendency to produce numbness, aud hence stun the bell and contribute

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An interesting discussion followed on the results of Captain M'Clintock's expedition, principally as determining the fate of Franklin, and also as it bore upon the progress of geographical discovery, in which several of the experienced explorers of the Arctic regions present took part, including Sir Edward Belcher, Captain Collinson, Captain Sherard Osborn, Captain Hobson, Captain Snow, and Captain Kennedy. Captain Collinson gave it as his opinion that after Franklin and his comrades abandoned the ships, it was almost impossible, having regard to the question of provisions, and to the probable rate at which they would be able to travel, encumbered as they were with sick, with boats, and facilities for prosecuting their journey, that they could have reached further than the bottom of the estuary of the Great Fish River, and that they all perished. Captain Sherard Osborn, as an Arctic navigator, said he could not resist the conclusion that the search for Franklin was now closed. He had read Captain M'Clintock's journal, which was written from day to day, without any wish to arrive at a particular theory, and therefore on that ground eminently valuable, and he felt that, whatever the track Franklin and his comrades took after abandoning the ships, it was their last journey upon earth, and that they must have perished. Captain Snow in an animated speech stated the reasons for believing it possible that some members of the Franklin expedition still survived, which he has already propounded in the public journals. He submitted that the evidence was not conclusive that they were all lost, and that it would be to the honour of Eng. land to make an attempt worthy of her honour to ascertain their fate. He pledged his word, if health were spared to him, and whether he was assisted or not, that he would depart next spring, with the view of going over the whole ground, and, if need were, would ally himself with the Esquimaux until the riddle was solved. Sir R. Murchison, in adjourning the meeting, said it was a great fact in which all those naval officers who had taken part in the discussion, whether belonging to Her Majesty's service or to the mercantile marine, agreed that, although Captain M'Clure was worthily rewarded for making a North-West passage, Franklin was the man who made the North-West passage.

A vote of thanks having been unanimously accorded to Captain M'Clintock for his memoir, the meeting separated at nearly 11 o'clock.

THE SOCIETY OF ARTS.

The first ordinary meeting of the 106th session of this society was held on Wednesday evening

within their hall, John-street, Adelphi. The attendance was numerous. The chair was taken at 8 o'clock by Sir Thomas Phillips, F.G S.

The Chairman, after numerous applications for admission to the membership of the society, and other routine business had been proceeded with by the secretary, rose, and after alluding to the time-honoured custom of the society, that the

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In the construction of ships there are, as we have already stated, two planes which may be made first, that of the load water line, and the other a use of as the horizontal plane of projection; the Sir Hugh Cairns and Mr. Jessel appeared in the rabbet of the keel. When the plane of the horizontal plane through the upper edge of support of the motion; Mr. H. F. Bristowe op-load water section is taken as the horizontal posed the motion on behalf of the defendants.

The Vice-Chancellor, after observing that even

where there might be considerable doubt as to the validity of the patent, still where there had been long and undisputed enjoyment the Court would grant an injunction, though upon terms to be imposed on the plaintiff, said that the statement of the defendant as to the want of novelty in the plaintiff's invention, which had been patented as long ago as 1848, was entirely unsupported. ever there was a case of clear and undisputed possession and enjoyment it was this.

session should be opened by an address from the
chairman of the council, acquainting members
with the policy which the council designed to
follow during the ensuing session, proceeded to
notice the decease of several members, the election
of Sir William Page Wood to a vice-presidentship
left vacant by the death of Robert Stephenson,
and the Exhibition of 1862. The progress of art and
the organisation of local boards were next re-
ferred to in the address. It was also intimated
that the Turner and Vernon collections of paint-matter had been actually tried at law he could not,
of course, say that there might not be a case to

If

Until the

plane of projection, the transverse sections being drawn perpendicular to it, the same method of calculation as that given in our first example must be followed for obtaining that portion of the displacement bounded by the extreme, horizontal and transverse vertical, sections; but since in ships which draw more water abaft than forward the plane of the load water section is not parallel

to the rabbet of the keel, the lowest section exclusive of the keel; there will, therefore, be an cannot be made to inclose the entire displacement appendage between the lowest section and the bottom of the keel similar to that represented in part of keel. Besides this the rudder and posts

ings at South Kensington would shortly be opened be tried. Then as to Dry's patent, looking at the Fig. 19, included between 54 W. L. and the lower

to the public during the evening. The present state of the law of copyright was next referred to, as well as another important matter which had been brought before the society under the presidency of Dr. Whell, and which had occupied desirable to establish a uniform musical pitch. It remains with the committee appointed to consider and report what pitch shall be adopted in this country. A large mass of correspondence has been collected during the vacation on the subject. The address concluded with showing the vast increase in commerce, arts, and manufactures that had taken place during a recent period.

much of the attention of the council-that it was

Mr. Webster, who rose to move a cordial vote of thanks to the chairman for the address just delivered, expressed his fullest confidence that the announcement of the determination of the council to organise an industrial exhibition in 1862 would be sympathised with throughout the country. He felt confident that through the progress of art and science a quinquennial exhibition might now be proceeded with, independent of the position of foreign affairs. He urged the importance of cooperation, and, in conclusion, drew attention to the present state of the law of copyright and of

trade marks.

Sir W. Page Wood rose to second the motion, and return thanks for himself personally for the honour conferred on him by his nomination to fill the office so recently vacated by the lamented death of Robert Stephenson.

Several members next joined in a discussion relative to securing other premises, when, after the presentation of medals to various persons, the meeting was adjourned until next Wednesday, when Sir John Bowring will read a paper on the arts and manufactures of China.

MEETING FOR THE ENSUING WEEK. TUESDAY. Inst. Civil Engineers, Discussion "On the Government Water-Works, Trafalgar Square," and, Outfalls," by R. B. Grantham, Esq., M. Inst. C.E., at 8 p.m.

specification, anything more unlike it than the plaintiff's patent could not be suggested. At present he was very far from feeling that it was a the defendants, and the injunction must be case of strong doubt, as had been suggested by granted, the plaintiff undertaking to bring an action and abide by any order as to damages.

COAL BURNING LOCOMOTIVES.

COURT OF QUEEN'S BENCH, Nov. 16.-(Sittings in Banco, before Lord Chief Justice Cockburn and Justices Hill and Blackburn.) THE MANCHESTER, SHEFFIELD, AND LINCOLNSHIRE

RAILWAY COMPANY v. WOOD.

magistrates of Sheffield, whereby they had conThis was an appeal from a conviction by the victed the Manchester, Sheffield, and Lincolnshire Railway Company of using upon their line a locomotive engine which was not "constructed upon the principle of consuming and so as to consume its own smoke." The case stated that the engine No. 37 was seen emitting black smoke for four minutes at the Sheffield Railway station, at 4 o'clock in the morning, and afterwards, when it moved along the line, it was again seen for four minutes emitting black smoke. The company, when summoned before the magistrates contended that the engine in question was constructed on the best known principle for consuming its own smoke; but the magistrates without entering into this question considered that the fact that the engine emitted black smoke was conclusive that it was not "constructed on the principle of consuming and so as to consume its own smoke," as required by the 114th section of the 8th Victoria, cap. 20, and fined the company £5.

Mr. Quain, for the respondents, contended that the magistrates were right.

Mr. Mellish, for the appellants, contended that the magistrates ought to have gone into an in

abaft the aftermost section must be taken when the ship is built of wood; also where the stem be added, and as its lower part is inside the before the foremost section at the upper part must curves inwardly at the foot, a portion situated

extreme sections, and not terminated by them, the space between the stem and the extreme sections is assumed to be of the same thickness as the stem when measuring off the ordinates, and the portion thus taken in excess is afterwards subtracted from the result first obtained.

Our former example and the above observations will, therefore, be sufficient to explain the method of performing the calculations in any case where the plane of the load water line is taken as the horizontal plane of projection.

The adoption of the plane of the load water section as the horizontal plane of projection is obviously the most simple for making the ordinary calculations, but it is open to the following objec tion:-When the building draught has to be made it is necessary to take the horizontal plane through the upper edge of the rabbet of the keel as the plane of projection, consequently there is a large amount of labour necessary to shift the planes of projection in addition to the operation of taking off the planking; constructors, therefore, who have little time to spare, first complete their building draught, and afterwards put on the planking, for the purposes of calculation retain ing the same planes of projection. It is evident, therefore, that the curves drawn in the halfbreadth plan are the projections of the several horizontal sections of the ship on a plane inclined to their planes; and further that transverse sections drawn perpendicular to the load water section would not be represented, in the half-breadth plan, by straight lines perpendicular to the middle line, but by curves, in obtaining which much time would be expended. The projections of the horizontal sections are, however, made use of for

if time permits, a paper "On Arterial Drainage and quiry as to whether or not the engine in question the purposes of calculation, and, as we shall prove,

Law Cases.

MIDWORTH'S PATENT BEATERS.

VICE-CHANCELLOR'S COURT, Nov. 16.-(Before Vice-Chancellor Sir W. P. Wood.)

GOUCHER v. MIDWORTH.

This was a motion for an injunction to restrain the defendant from manufacturing and selling thrashing machines with grooves or channels in the surface of the beater, in imitation of the plaintiff's patented thrashing machine, and generally from infringing his patent, which was taken out in November, 1848. The case set up by the defendants was that there was no novelty in the plaintiff's patented invention, which was in effect a mere colourable imitation of an older patent taken out by one Dry in 1842, now expired, and of which there were several modifications in con

was constructed on the principle of consuming and so as to consume its own smoke. It might have been that the only cause of the engine's smoking was the negligence of the engine-man. Lord Chief Justice Cockburn said the Act did not say that the company should be liable to a penalty if their engines emitted smoke; and this Court could not go beyond the Act of Parliament. The fact that the engine emitted smoke would be strong evidence that the engine was not "constructed on the principle of consuming and so as to consume its own smoke;" but it was not conclusive. The case must go back to the magistrates to inquire whether or not the smoke arose from the defective construction of the engine. If the Legislature had intended to say that the company should be liable to a penalty. under all circumstances, where an engine emitted smoke, it would have used a more stringent enactment.

Mr. Justice Hill and Mr. Justice Blackburn were of the same opinion.-Case remitted accordingly.

the displacement so found is essentially correct.

We shall, therefore, assume that the planes of projection are those generally made use of for the building draughts, and that the curves in the half-breadth represent the projections of the horizontal sections of the ship at the outside of the planking. And by way of example we will perform the calculations for a ship of war of the following dimensions :—

Length between the perpendiculars.. 180' 0" of the keel for tonnage Breadth, extreme

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for tonnage moulded

Depth in the hold... Burthen in tons No.

(Forward..

Draught of water {Abaft.....

160 7

28' 4"

28′ 0"

27' 6"

16' 0"

670

12 feet.

14 19

Our object now will be to obtain the areas of the curvilinear figures on the half-breadth plan. For this purpose the foremost and aftermost sec

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tions or ordinates are placed at the rabbets of the stem and post, as before explained; and the distance between them, measured on the middle line of the half-breadth plan, is divided into a number of equal portions suitable for the application of the rules given for obtaining curvilinear areas, and at the points of division lines are drawn perpendicular to the middle line. These lines represent transverse sections perpendicular to the upper edge of the rabbet of the keel, and in Fig. 19 are represented by the vertical sections 1, 1, 2, &c.

The ordinates are then measured off from the half-breadth plan, and inserted in the table, as already described in our former example, and the calculations proceeded with as though the transverse sections were perpendicular to the load water sections.

In our present example, the distance between the extreme vertical sections measured on the middle line is divided into 18 equal portions, each being 9-4 feet; and for greater accuracy, the two extreme intervals are again divided into two equal portions respectively, as is shown in the Fig. 19. In placing the horizontal sections they are so arranged that the third rule for approximating the curvilinear areas may be applied. There are

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the multiplication by the fraction will be necessary.

Let us assume, however, that we have obtained the true areas of the horizontal sections, and let them be respectively represented by A1, A2, A3, 44, 44, 45, and 45.

To obtain the displacement from these we have only to multiply them respectively by 2, 6, 6, 3, 3, 3, 3, and 1, in accordance with the third rule for finding a curvilinear area, and their sum mul. tiplied by ths of the perpendicular distance between the sections, will give the displacement. Now, the perpendicular distance between any two sections is equal to the distance between them, measured on a vertical section, multiplied by the it is obvious, therefore, that if we make use of the projections of the areas of the horizontal sections (which are the true areas multiplied by the fraction and take the distances between the horizontal sections, as measured on a vertical section, we shall obtain the correct displacement.

fraction

7 6 5 4 3 2 first have their projections on a plane perpendicular to the load water line, and not their true areas, but as before the true displacement will be ob tained when these are put into the rule, and the common interval taken as measured along the horizontal sections.

With these observations, we shall leave the student to work out the example for himself, as no difficulty can present itself respecting that portion of the displacement which is inclosed by the extreme sections; the work is precisely the same as in our former example.

The small portions of the displacement situated outside of the extreme sections are found by the ordinary rules of mensuration, as also are their centres of gravity, and the necessary corrections are made in the results before obtained.

5

W. L. contains 167 cubic feet, and its centre of In the present example the portion below gravity, situated at b, Fig. 19, is 120 feet from section 1, and 12-5 feet from the L. W. L.

The contents of the rudder and stern posts abaft the section 19 are 65 cubic feet, and the centre of gravity situated at c, Fig. 19, is 180 feet abaft section 1, and 6-25 feet below L. W. L.

at the upper portion of the displacement four tions, the rationale of the operations will be sections, which must be subtracted, contains 22.8

equidistant sections, and at the lower portion four other equidistant sections. The common 2 W. L.; 2 W. L. and 3 W. L.; 3 W. L. and 4 W. L., is 2.65 feet, measured on the sections drawn perpendicular to the rabbet of the keel, and the common distance between the sections 4 W. L. and 4 W. L; 4 W. L. and 5 W. L.; feet, measured on

distance between the sections L. W. L. and

2.65 2

5 W. L. and 5 W. L. is the same sections. Performing the calculations in the same manner as described in the former example, we obtain first the areas of the projections of the several horizontal sections; and before being multiplied by rd of the common interval they are to be found in the first horizontal column below the ordinates; they are 32.75, 93.75, 19475, 297.5, 452.8, 550.95, and 621.4. Suppose we have multiplied these results respectively by one-third of the common interval, and so obtained the areas of the projec. tions of the several horizontal sections, these areas will be equal to the true areas of the respective sections, multiplied by the fraction L being Τ

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To obtain the displacement by transverse secbetween the horizontal sections is measured along readily made out. For, since the common interval the transverse sections in the sheer plan, when the ordinates for any section are put into the rule, and the sum multiplied by the proper fraction of the

common interval, the result will be the true area of that section. And since the common interval between the transverse sections is the perpendicular distance between any two consecutive ones; when their areas are put into the rule, and the sum multiplied by the usual fraction of the common interval, the result will evidently be the displacement.

Another explanation may be given of the manner of finding the displacement inclosed by the extreme sections from the projections of the building draught. Taking, as before, the extreme outside of the planking, as delineated on the transverse sections at the outside of the rabbet of the stem and stern-post at the load water line, L. W. L. in the sheer plan, and then divided into let the distance between them be measured on the the same number of equal parts as was the distance between them on the middle line of the half-breadth plan, and through the points of division let transverse sections be drawn perpendicular to the upper edge of the rabbet of the keel; these sections will, of course, coincide with those before drawn, but since the common interval is measured on the horizontal sections, the true areas of the horizontal sections will be found on the table, and not their projections as before. Again, the common interval between the horizontal sections must now be measured perpenareas found in the table may be taken as the true dicularly to them, and not along the transverse areas of the sections, without any practical error; sections, as in the former case; it is easy to see, and it is only in cases in which the difference of therefore, that the true displacement will in the draught of water forward and aft is very consider-end be arrived at by the horizontal sections. able in proportion to the length of the ship, that To proceed with the transverse sections we shall

the distance between any two vertical sections, measured on a horizontal section, and the distance between them measured on the middle line of the half-breadth plan; the true area of any horizontal section may therefore be readily found from these areas given in our table. Generally, however, the fraction is so near unity that the Ī

The portion between the stem and the extreme Fig. 19, is 25 feet abaft section 1, and 9-5 feet cubic feet, and its centre of gravity, situated at a, below L. W. L.

The positive portions amount to 167+65, or 232 cubic feet. The negative portion is 228; cubic feet, which must be added to 28198-2757, the total positive appendage is therefore 209-2 the displacement situated between the extreme sections, to obtain the total displacement. In forming the scale of displacement, the proper

appendages must also be taken into the calcu

lations.

Again, in obtaining the centre of buoyancy in our former example, there were no appendages to the displacement. In the present case, the centre of buoyancy corresponding to the portion inclosed ample, and it then remains to find the effect of by the extreme sections is found as in that exthe appendages upon its position in a vertical and also in a horizontal direction. This may be readily gravity proved in our last article, page 215. done by means of the property of the centre of Assume that the axes o x, oy both pass through the centre of gravity, above found, of the displacement inclosed by the extreme sections, and that they only to find the moments of the appendages are parallel to L. W. L. and section 1, then we have about ox and oy.

the centre of buoyancy without the appendages On reference to the table it will be found that from section 1; consequently the centre of gravity is 4.3115 feet from the L. W. L. and 86.69 feet of the keel piece is 12-5-4-3115, or 8.1885 feet from the L. W. L.; therefore 167 x 8·1885 = 1367-5 is the product of its weight and distance from ox, also 6-25-43115-1.9385 is the distance of the centre of gravity of the rudder and posts from and 9.5-4.3115-5-1885 is the distance of the negative portion forward from the same axis,

0x;

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ORDNANCE.

therefore 65 x 1.9385=126'0, and 22.8 x 5.1885= | CAPTAIN COLES' PATENT SHIELDS FOR 1183; the sum of the positive products is 1493 5, and the negative product 118.3, the result will therefore be positive, and equal to 1375-2. This quantity divided by 28407, the total displacement in cubic feet, including appendages, will give 0485 feet for the distance of the centre of buoyancy below that corresponding to the displacement between the extreme sections, or the centre of buoyancy below L. W. L. is 4-36 feet. In a similar manner, the distance that the centre of buoyancy moves aft by the addition of the appendages may be found to be 34 feet, as given in the table. The centre of buoyancy is therefore 87-03 feet abaft section 1, when the appendages are taken into account.

The student will now, we think, be able to make the ordinary calculations for any ship, with either of the usual horizontal planes for the plane of projection, and in the above example he will complete for himself the drawing containing the scale of displacement, the scale of the area of the midship section, and that of the tons per such immersion similar to those given on page 298, vol. I., for our first example.

MONSTER TROOP STEAMER.-The following paragraph has been communicated:-Messrs. Pearse and Co., Stockton, have on the stocks for the Government an Indian river steamer of immense proportions. Her length in the water-line is 350 feet, over all 375, and breadth 46 feet. She is by far the largest river steamer in the world. Her engines are 200 horse power. She will be impelled by paddles, and will, it is expected, attain a speed of 13 miles an hour. She will be fitted with sleeping berths and every suitable sanitary arrangement for about 800 soldiers. She will be guided by two large patent steering blades, and is made to draw only two feet of water, even with all her stores, fuel, and 800 passengers on board. She is flat-bottomed of course, and weighs about 370 tons. She will be completed in about a month, and will then be fitted up on the Thames, in order to make an experimental trip.

CAPTAIN COWPER PHIPPS COLES, R.N., has recently patented an apparatus for defending guns and gunners in ships of war, gunboats, and land batteries. His invention consists of a large convex shield covered all over its exposed portion with thick iron or other metal, and mounted upon a platform or frame which is capable of revolving after the manner of a turntable, and which also carries the gun upon any suitable carriage. An aperture is formed in the shield to allow the muzzle of the gun to pass through it, and this aperture is somewhat larger vertically than horizontally in order to admit of the elevation and depression of the gun, the lateral aim being secured by the rotation of the platform. Captain Coles does not limit himself to any precise form or mode of construction, but he usually prefers to make the shield hemi-spherical, and to construct it of a wooden frame with timbers in vertical planes placed close together, the whole being covered with thick iron plates. In the engravings hereunto annexed, we have illustrated the manner in which he carries his invention into effect. The figure is a transverse section of a shield, constructed according to his invention, and adapted to a land fort or battery. The body of the shield is composed of a compact framing of timber 4, the whole exposed upper portion of which is covered with thick iron plates B. The shield is built upon a revolving timber platform or frame C, which turns about a central bolt or stud D, and runs upon conical rollers E, placed beneath it near its circumference. These rollers are carried by arms F, which are attached to a loose running central ring G. The conical rollers E, run upon a metallic rail or tram, supported by a floor or platform H. The rotary motion which is requisite in the training of the gun is obtained by means of a hand-wheel I, fitted within the shield and connected with gearing, which works a pinion K, that travels round in teeth or cogs formed upon the circumference of the metallic rail or tram. I is the aperture through which the gun protrudes.

The aperture L is only sufficiently wide to allow the muzzle of the gun to pass through it, but is of sufficient size vertically to allow of the depression and elevation of the piece. A narrow aperture l is continued up from the main aperture L, to admit of the gunner "sighting" the gun with ease and accuracy. When the shield is formed and fitted as shown in the engraving, the ammunition must be supplied through an aperture made for the purpose in the rear of the shield. But in some cases, as on board ship for example, Captain Coles prefers to employ a hollow cylindrical casing in place of the solid central bolt or stud D, and pass the ammunition up from below through it. In like manner he proposes in other cases to modify other details of the apparatus. Instead of making the shield of an arched or curved form, for instance, he makes it polygonal in horizontal section, and straight-sided in vertical section, or of any other prismatic or other form, which will present a convex or inclined surface throughout to shot and shell. He likewise sometimes mounts the shield upon spherical balls, or rollers, or otherwise, instead of upon the conical rollers before described, and in place of the hand wheel and gearing for rotating it, he employs any other suitable appliances for the purpose. Further, he provides for the escape of smoke from the shield, and for its ventilation, by forming apertures in it for the purpose, and sometimes (as where a central upward passage is provided for the ammunition) by forcing air continually through the shield by means of a fan placed beneath it. Finally, he proposes to form the shield large enough in some cases to cover two or even more than two guns side by side and parallel to each other. When the shield is employed on board ship it should be either built or placed somewhat eccentrically in order that the common centre of gravity of the shield and the gun or guns beneath it may be caused to fall in the centre, about which the whole rotates. This will prevent the same from having any disposition to rotate imparted to it by gravity as the ship rolls or pitches. Captain Coles prefers to mount the guns placed beneath the shield upon

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