DESCRIPTIVE CARPENTRY, the art of forming a diagram on a plane by the rules of geometry, in order to construct any piece of carpentry of a known property, from certain given dimensions of the thing to be constructed.
This branch is only the application of stereography to Carpentry : and, indeed, the only difference between stereo graphy and descriptive carpentry, is, that in the former, the bodies are entire solids, but in the latter, the bodies to be formed consist of ribs, disposed in parallel lines or planes, or in lines tending to a point, or in planes to an axis ; ' so that descriptive carpentry shows the methods of forming the separate pieces in order to construct the whole body or solid. Stereography is, therefore. sot only employed in the construction of individual pieces, but also in the whole, when brought into a mass, or taken as one body. This branch is a necessary qualification to an architect, not only to enable hint to anticipate the effect, but to judge of the propriety of the execution of any proposed work.
It is too often the case, that young men professing to he studying the science of architecture, will not submit to that which they are pleased to deem the drudgery of the profes sion. Instead of acquiring, by constant practice and studious diligence, the necessary elements of descriptive and construc tive knowledge of the various parts of an edifice, they attempt, before they are qualified by such knowledge, to design edifices, flinciful in conception, as they would be ridiculous if executed.
The. result of this want of careful training, is well described by Mr. Bartholomew, in the following passage :—" Taken from school at an age in which he cannot have imbibed in any degree sufficient of a pulite and liberal education, the architectural pupil, frequently with no knowledge whatever of geometry, never acquires any beyond the mere manual dexterity of drawing circular and plain lines ; abandoned by his master while vet scarcely arrived at manhood, forced into premature and profitless practice with all the expenses of a separate establishment, it cannot be wondered at, that the adolescent architect sometimes has, in after-life, bitter cause to repent the circumstances and the rashness, which led him to acquire practical design and practical construction, solely by his youthful failures ; for it is then, with deep repentance. that he perceives the contusion of styles into which he has Olen, the whole chronology of gothic arches which he has paraded in the same facade, the mixture of Roman forms and luxury with the severe and elegant sim plicity of the Greeks ; in many a breaking up and fracture, he has the mortification to find that inventions upon which he his relied for eternal duration, have not survived their inventor's ruin ; that he has formed his pinnacles with graduated outlines, as if Rosslyn chapel or some other impure source were his only pursuit ; he regrets that lie has placed his columns opposite apertures, instead of opposite piers ; he regrets that, from fidse bearing, want of plumb and equi poise, his work is so fractured, that even a man of more experience than himself cannot restore it ; he perceives too late, that his patronage of mean and fragile stone, and pretended substitutes for it, his reliance on bad timber, has added something to the wreck of his country's architecture ; he perceives NN ith deep mortification, that his want of mathe matical and mechanical skill, both theoretical and practical, has led hint to perform that which a professor of more experience would avoid ; broken arches, tie-less roofs, walls thrust from their right position, partitions falsely trussed, and groaning beneath loads which, formed otherwise, they might have borne unflinchingly. and a foundation which
fails in all directions front want of sufficient spread to the footings, or from the building being carried up piecemeal, or from other causes—these are a few of the limits and disasters, which in after times make a precocious practitioner wish he had studied five or ten years more, before lie had risked himself or his employer's property." This was not the case formerly ; men endeavoured in those days to qualify themselves for the practice of their profession, by long study, practice, and unceasing diligence.
Architects, among the ancients, were highly accomplished characters, being skilled in all the geometrical and mechanical knowledge of their time ; and in this country they have had much claim to eminence as late as the reign of Queen Anne. Since that time, however, a gradual declension of the art is equally perceptible in all public edifices, as well as in all works of architectural literature.
Though travelling adds to the accomplishment of a judicious architect, it is among the least of the necessary qualifications; a careful observer will lay up greater stores of knowledge at home, than he who has travelled, with inferior abilities ; and, indeed, it the architect have no farther views. than that of travelling, in order to produce what lie calls drawings of taste, he will. in most instances, become ostentatious, and will ultimately lose the good opinion of his employers. Travelling improves the man of science. but inflates the sciulist with vanity, and renders hint ten times more a subject of com miseration than before.
As those parts of carpentry which are objects of descrip tion, are placed under their proper denominations, the reader is referred to each particular term, for further information upon this useful subject.