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Fourthly, The invention of a round chariot of metal, made of the proof of double mufket, whofe motion thall be fuch, that those that be within the fame fhall be more easy, more light,' more speedy, and more fafe in battle, than any hitherto contrived. The ufe hereof in moving, is to break the array of the enemies battle, and to make paffage, as also in staying and abiding within the enemies battle. It ferveth to deftroy the environed enemy, by continual charges and fhot of the Harquebufe, through fmall holes, the enemy in the mean time being abafed, and altogether uncertain what defence or purfuit to use against a moving mouth of metal.

Thefe inventions, befides devices of failing under the water, with divers other devices and ftratagems for harming of the enemies, by the grace of God, and work of expert craftsmen, I hope to perform.

(Signed)

JOHN NAPIER of Merchifton. Anno Domini 1596. June 7th.

Obfervation.

If Mr. Pitt is really ferious in his Quixot plan of fending a fleet to the Baltic, the above inventions would be fingularly useful, and may be looked for at the waroffice fome rainy Sunday, when the fecretary has nothing else to do. AS.

On the Mechanical Principles of Gothic Architecture, continued from Page 348, Vol. II,

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On the Origin and Ufes of the Central Towers in Gothic Cathedrals.

THE veneration that Chriftians bore for the rofs, in duced them to adopt that form, in preference to all o

June 1 thers, in their churches. The body of the church.extended to a great length, from eaft to weft, confifting of its nave, and fide aifles, and the tranfept croffed it at right angles from fouth to north. As this tranfept was generally of the fame height and width with the nave, it followed, that no light could be thrown from above into the large central fquare, had it been finished off at the fame height with the other parts of the nave. This would have thrown a kind of gloom upon the centre, instead of making it the moft cheerful part of the building, as its confpicuous pofition rendered, in fome measure, neceffary. There also was wanting an abutment to the long row of arches on each fide of the nave, which could not have been well effected by the large pointed central arch of the tranfept alone; fome contrivance must be therefore adopted for providing here an abutment for the purpose wanted, that fhould not incommode the church. The device the architect adopted here, is like all the others we have had occafion to develope, beautifully fimple and efficacious, and has been fo managed, as to answer feveral other beneficial purpofes, befides thofe which, of neceffity, gave rife to the object in queftion.

To form the abutment wanted, it became neceffary to load each of the four central corner pillars with fuch a weight as fhould become a counterpoise to all the range of arches that abutted upon them. This was effected by rearing up a wall upon the top of the central arches, exactly upon the fame principle as that on which were reared the walls above the pillars of the naves; but as the preffure here was great, the weight wanted was much more confiderable than in the other cafe; and therefore it became neceffary to rear these walls to a much greater height. Here then we fee the origin and primary ufe of thofe central towers that conftitute a peculiar and ftriking characteristic of that Tpecies of Gothic ftructures now treated of.

In rearing thefe towers, the fkilful architects faw how easy it was to introduce the light that was wanted, to the central part of the building. It was only to put into each fide of the fquare, which conftituted the base of the tower, a large window, on the fame principles with the other windows made in these buildings, which, by thus affuming the fhape of à common lantern, has obtained the name of the lantern of the tower.

But as it would have had a disagreeable effect to have made the infide roof of these lanterns as high as would have been neceffary for the walls, and would have been in certain mechanical refpects attended with difficulties, they commonly threw crofs arches over that tower as ufual, making them all meet at the centre, and forming a roof at no great height above the top of the windows. These higher arches required in their turn abutments, which was effected by elevating the walls of the tower still higher: And as bells were wanted for the church, a place was made in the tower, above the lantern, for receiving the bells. Where the tower was not to be reared to a great height, these were fometimes roofed in with a wooden roof. Sometimes, however, a ftone arch was thrown over the divifion for the bells alfo, which, if as flat as ufual, required, that the walls of the tower fhould be carried to a greater height ftill, to ferve as abutments. Thefe walls were of course, in these cases, cut off fquare over at top, being fometimes ornamented with some kind of railing or battlements, with fmall turrets at the corners for ornament. Such, then, is the origin and ufes of thofe maffy central towers, and fuch is the reason why fo many of them have been finished fquare off at top, as, they are fo commonly to be feen in England.

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Sometimes, however, it was thought, that a high central pointed roof to thefe towers would be ornamental; and where that was wanted, it also was effected. This was done by making the fpire for the most part VOL III.

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June 1, of wood, on account of its lightness. To render the preffure upon the abutment the lefs, thefe fpires were made very high and pointed, and their base was receiv ed into the fquare tower confiderably below the battlements. Of this kind was the ancient fpire of old St. Pauls London, and that of Lincoln cathedral, at this day, and many others. Sometimes fpires of ftone formed the top of pretty high towers, as on the two weit towers of the Church of old Aberdeen. Sometimes this was done even over the central towers; but as the great weight of this load must have been too much for the counterpoife wanted, if thefe central towers had been carried up fquare to a confiderable height, they found it neceffary, where a ftone fpire was intended, to make the arch extremely pointed indeed, and tó cause it be begun as low down as poffible; fo that the weight, which, in the other cafe, was put into the perpendicular walls, was here thrown chiefly into the cone. Sometimes, however, they proceeded to exhibit a yet higher exertion of their mechanical powers, by crowning thefe central towers with open arched ribs of stone, fupporting pinnacles of confiderable altitude. As this is perhaps the climax of mechanical invention that has been attained by thefe artifts, I fhall think myself par donable for endeavouring to develope, with all poffible brevity, the principles on which towers of this kind have been conftructed.

I have seen three towers crowned in this manner: Thofe of St. Nicolas church in Newcastle; the college church at old Aberdeen; and the central tower of St. Giles's church Edinburgh. As this last is more under my eye than the others, and as it is generally esteemed a moft beautiful tower, my defcription fhall chiefly apply to it.

The problem here propofed to the architect, feems to have been fomewhat of this nature: "To rear up a certain number of open ribs of ftone work, on the principles of an arch, above the top of a wall of the

tower, and to give to the whole fuch a form as "would make it an elegat finishing to the tower :" And the architect, after having fettled in his own mind what was the form of arch that the circumstances ren dered practicable, and the adjuncts required to give it the neceffary ftability, feems to have felected the papal crown as the object it would be most eafy and proper for him here to attempt to imitate, by giving arbitrary forms to the parts that could not be difpenfed with, that should accord with the general figure of the tiara.

With these ideas he proceeded, being happy to find that the high conical form of the tiara accorded very well with the great elevation and freightnefs of the rib, that was neceflary to make it fupport itself with fo fmall a load upon its outfide as the circumstances of the cafe required. By this means, he was enabled to make the ribs much more flender, and of courfe lighter to the eye, than otherwife could have been practicable. By this means too, he was enabled to make the pinnacles at the bottom much fmaller than would have otherwife been neceffary*, as well as to rear upon the top a higher and more elegant pinnacle than would otherwife have been practicable.

Still, however, had the ribs been left totally bare, and of the slender structure our architect judged neceffary to produce the light effect he intended, notwithftanding its height, the preffure at the top would have been too great not to have endangered the flying outwards of the arch towards the middle. To counterbalance this preffure, therefore, he contrived to load each of the ribs with two pinnacles of proportional fizes,

* Still farther, however, to diminish the size of these bottom pinnacles, which would have otherwife been difproportioned to the others for the defign in view, the cautious architect has made the ribs themselves deeper at the bafe than the top It would form a pleafing object of research for a perfon of fkil, to compare the various devices tha: ha. bren adopted by thefe artifts for effecting the fam: purpose in different ci. ● cumftances.

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