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only ; the covering of a spheroidal dome with hoards havingtheir joints in parallel vertical planes ; the construction ofa dome with horizontal ribs, without taking the trouble' tosquare them by horizontal and vertical faces; the method ofcutting purlins and jack-rafters to fit the hips, without layingthe roof in ledgment; principles for the equilibrium of poly-gonal roofs without ties, so that the rafters may obtain a givenratio among themselves, provided the abutments be sufficient;a principle for preventing rafters without intermediate ties,from having any lateral pressure;—these two latter inven-tions have been several years before the public, in the archi-tectural plates of Eees’s Cyclopedia. To these might beadded various other principles of less importance, which it isnot necessary to recapitulate in this place. In most of thesubjects above alluded to, he has given more than one methodof operation, and in some instances he has multiplied hisexamples to five or six different modes of practice. One ortwo of the inventions in the foregoing list, he acknowledges,are only his own by their new application, the principlesbeing known prior to his time; but he has adapted them tosubjects to which they were never before applied; and heconceives that it requires at least as much ingenuity, and isfrequently attended with more utility, to be able to apply anold or well-known principle to an useful object, as to discovera principle destitute of practical application: he has, therefore,not scrupled to include them in the list of his discoveries.Nor has he, while thus claiming credit for himself, denied itto others; as may be seen in his remarks on Pain ’s lining ofa cylindric soffit in a circular wall, the principle of which waspreviously laid down by Price, in his centerings of groins.The inventions which the author has thus appropriated tohimself, are the following: the application of the principleof covering the surface of the frustum of a cone to a spheroidaldome, with the joints in vertical planes; the application of theprinciple of covering an oblong spheroidal dome by one mouldonly; and the application of the principle shown by Price,in his centering of groins, to a cylindric soffit for an aper-ture in a straight wall, with its axis oblique to the surfaceof such wall; which latter was likewise attempted by Pain ,but without success.
The author has not been able fully to satisfy himself as tothe extension of the surface for the head of an aperture,splaying in the sides and level on the crown, so that the aper-ture shall form a semi-circle on one side of the wall, and asemi-ellipsis on the other; or a semi-ellipsis on each side, butof different horizontal dimensions, though of the same height.He is, however, convinced, that though the form be not geome-trically true, it is much more correct than anything attemptedby Langley or Pain ; and on it, he has accordingly foundedthe principle by which alone the nature of the solid itselfcan be understood. And though unsuccessful in his attemptsto extend the surface exactly, he has had the satisfaction oflaying dawn such lines as will apply to the surface of thesolid with far greater accuracy and dispatch, than could beobtained by the mechanical operation of plumbing the linesfrom the plan; by applying the distances on the plan upontheir respective level lines on the surface of the solid, alldrawn from one vertical line resting on the point where thetwo sides of the splay come in contact. By this means theline of every wall may be found correctly on the surface,whether the wall be straight or curved, or whether the axisof the solid stand oblique or at right angles to its sur-face ; which cannot be done by any other method hithertoattempted.
In conclusion, it may be observed, that writers on carpen-try have frequently been unsuccessful, for want of groundingtheir schemes upon the simple principles of the bodies they
wished to construct; by losing sight of which, they havefallen into puerile operations, and drawn erroneous influ-ences. .
In the course of this work, we shall treat of the severabranches of the building art, and each article of thosebrandies, in a manner similar to this on Carpentry; and atinventions, as well useful as otherwise, with every unsuccess-ful attempt at geometrical construction, will be noticed undertheir respective heads.
It is now only necessary to observe, briefly, that as tnarrangement and classification of the subjects, as well as themode of conceiving and presenting them in the diagrams, ai ealtogether different from those adopted by the writers wb®have preceded us in this department, so it is believed, thathis method will display the art of carpentry in a novel po> nof view, and reduce it to that pure scientific form it has ne ' ethitherto acquired. But notwithstanding all that has bee°done, and the great advances made in the art since the p ulication of the various works we have been examining, l£ 1evident that the subject is not exhausted, but is still suscep^tible of many improvements. Such improvementsdoubtless be effected, in time, by the labours of ablmen who will carry to perfection the science and P raC ^tice of an art so important and so interesting as that 0Carpentry.
CARPION, a Grecian architect, who wrote a treatise 011the Temple of Minerva, in the citadel of Athens.
CARRIAGE of a Wooden Stair, the frame of timbe rwork which supports the steps.
The carriage of a flight of steps, supported on one sidea wall, generally consists of two pieces of timber, incline®the pitch of the stair. These pieces are called rough-stnW ’or carriages.
When a geometrical stair consists of two alternate fl'S 1 ’ 1 ’with a half pace between, the carriage of the half pace c° ^sists of a beam parallel to the risers of the steps, and seV f 1 ( , ijoists framed into the beam, for the support of the boardJ'JoThe beam which sustains the joists, is called the apron-f lC £and that which sustains the rough strings at the upper en^is called a pitching-piece. The joists of the half pacesometimes tenoned into the pitching-piece, and sometnbridge over it; but the steps of both flights are supportedstring-pieces, as before. The upper ends of the string-P ieat the landing, rest upon an horizontal piece of timber, deminated an apron-piece. _ 0 f
If the steps wind round a circular newel, the carriafcthe circular part consists of uprights and bearers, the n | ]gof which are wedged into the wall; though it will answer^purpose as well, to frame them into a string placed ag<the wall. The uprights and bearers are either framed 'mortises and tenons, or are dovetailed together. ir) d
When the staircase is of the dog-leg kind, with windei 3a close newel, the carriage is formed of bearers let m t0wall, and fixed to the newel post. For more information,Stair-Casing and Hand-Railing.
CARTELLI. See Cartouches. _ .i^k
paper, or pasteboard), in painting, a design on strong- - - - ’ ®ii
The
g P<
to be afterwards chalked through, and transferred on a ne g fAplastered wall, which is to be painted in fresco. The ,^ t0is also used for a coloured design, that is to be wrougnmosaic or tapestry.
CARTOUCHES, or Cartoozes (French , from the ^ ce sCartoccio), a kind of blocks or modillions, used in the c °of wainscoted apartments; differing from modillions mconfined to the interior, whereas modillions are apph eexternally and internally.