An introduction to linear drawing/Chapter 6
The pupils should here be required to exercise their ingenuity and taste in drawing similar figures, without copies, or by having real objects placed before them, such as books in various positions, articles of furniture, &c.
It is left to the Instructer's judgement, whether to take the Sixth Class, the Arithmetical Problems, or the Linear Perspective next. But before attempting either, the student should have gone over all the preceding classes several times on the slate, then with a lead pencil on paper, and lastly, with a pen and ink. Very young children may draw all the preceding figures, but it requires some maturity to draw the rest, and to apply the arithmetick.
SIXTH CLASS.
By the number and complication of details in the figures of this Class, it is evident that they are calculated only for practised pupils, who are skilful in drawing the figures of the five preceding classes, as well with the rule and dividers as without them.
At first the pupils should not draw the details of the frieze, capitals, &c. but merely the large and more important parts, giving them their just proportions, upon which their graceful appearance depends.
There are four modes of arranging the parts of a building, commonly called the four Orders of Architecture, viz. the Tuscan, Dorick, Ionick and Corinthian Orders.
Each has three principal parts, the Column, the Entablature which surmounts it, and the Pedestal which supports it. The pedestal is often omitted, and its place supplied by a plinth only. The order is then reduced to two parts only. Indeed, sometimes the edifice has no columns, but still it is said to belong to some order, because certain proportions are observed in its parts.
The Corinthian Order is distinguished by the rich- ness of the sculptures which decorate its frieze, and which are infinitely varied. The capital of the column is also furnished with two rows of leaves, and eight volutes.
The Ionick Order is distinguished by the volutes of its capital.
The Dorick Order has its frieze ornamented with triglyps and metopes.
The Tuscan, the most plain and solid of all the or- ders, allows no ornament.
Besides these characteristicks, the different orders are also distinguished by the proportions which regulate their parts, as will be shown hereafter.
Nothing is said here of a fifth order called the Com- posite, because it is composed of the Ionick and Corin- thian ; nor is mention make of the Gothick, Attick, German, and Arabick, for a complete treatise on archi- tecture is not intended.
By comparing the different monuments which artists have thought worthy to be considered models, on ac- count of the taste they exhibit, proportions have been noticed in the parts, which have become rules for imi- tation. Not that there exist in fact, exact and rigorous proportions and rules which are never deviated from, for art has not those fixed rules which are found in the sciences. Certain proportions having been ordinarily observed, and by the consent of all persons of good taste, being found the most suitable, these proportions should be considered as a rule not to be deviated from 5 without good reasons. The draughtsman, by strictly observing these proportions, is secured from criticism, is sure of doing well, and of obtaining the approbation of judges.
The following are the proportions thus settled :
In all the orders, the entablature is one quarter as high as the column, and tht pedestal a third.
Each of these three parts is subdivided into three others, viz.
The Pedestal into the Cornice, Dye and Base.
The Column into the Base, Shaft, and Capital.
The Entablature into the Architrave, Frieze, and Cornice.
Care must be taken to proportion the size of the col- umn to its order, its own height, and the height of the edifice it is to ornament.
The height of the Tuscan Column, including its base and capital, is seven times its diameter ; of the Dorick, eight times ; of the Ionick, nine times ; and of the Co- rinthian, ten times.
The subdivisions are also regulated by this scale. A radius, or half diameter of a column, is called a Mod- ule, which, when once ascertained,determines the height of the frieze, cornice, shaft, &c. These modules are each divided into twelve equal parts in the Tuscan and Dorick orders, and into eighteen in the Ionick and Co- rinthian.
The number of Modules, or half diameters, which the subdivisions of each order measure, is as follows. TUSCAN ORDER.
Column....................14 Modules.
Base -----------1
Shaft...........12
Capital - -- -- -- -- -1
Entablature...........Modules.
Architrave - -- -- -- -1
Frieze ..........
Cornice %.........
Pedestal.................4-y Modules.
Cornice - -- -- -- -- Dye...........3*. f tT
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In all, 22 Modules and and without the Pedestal, 171.
The Intercolumniation, or space between the bases of two columns, is 4-f- Modules.
DORICK ORDER.
Column....................16 Modules.
Base - - - -......1
Shaft...........14 ^ 16
Capital - -- -- -- --1
Entablature.............4 Modules.
Architrave - -- -- -- -1
Frieze...........H}*
Cornice - -- -- -- -- -
Pedestal.................Modules.
Cornice - -- -- -- -- -
Dye...........4
Base - -- -- -- -- -
In all, 25-f Modules, and without the Pedestal, 20 Modules.
The intercolumniation is h\ Modules. IONICK ORDER.
Column....................18 Modules.
Base..........- l }
Shaft...........16| } 18
Capital...........
Entablature............4$ Modules.
Architrave
Frieze........- - - ll 4$
Cornice - - - - - - - - - -
Pedestal...................6 Modules.
Cornice - -- -- -- -- - $ ^
Dye.............5 > £
Base - -- -- -- -- -- i }
In all, 28$ Modules, and without Pedestal, 22$. The intercoluraniation is 4$ Modules.
CORINTHIAN ORDER.
Column.................~.20 Modules.
Base...........1)
Shaft...........16y > 20
Capital...........2-f)
Entablature.............5 Modules.
Architrave --------- - 1$^
Frieze - - - -- -- - - -- 1$>5 Cornice ---------- 2 )
Pedestal.................Modules.
Cornice ----- 14 parts of a Mod. } Dye - - - - 5 Mod. 4 " " " J> Base - - - - -J "......)
In all, 31^. Modules, or, without Pedestal, 25. The intercoluraniation is 4| Modules. Thus, to raise an order of a given height, divide the height, as expressed in feet or inches, by the number of modules belonging to the order, and the quotient will be the module or semidiameter of the base of the col- umn. We say the base, because it is found that the column is more graceful if it insensibly diminishes to- wards the top, so as to lose one third of a module in the two upper thirds of the column.
The module, being thus ascertained, is divided into smaller parts, and thus gives the height of all the sub- divisions.
A vertical or perpendicular is drawn, on which are successively marked the lengths of the cornice, the frieze, the architrave, &c. On these points, horizon- tals are drawn, between which will be contained all the mouldings of the order.
Or—if the circumference of the base of a column be measured with a string, and multiplied by 0,159, the module will be found ; and from this, the height of the whole edifice, and of all its parts.
Pediments are triangular structures, whose height may be much varied according to their extent. There are some whose height is a third, fourth, fifth or sixth of the base. This proportion is left to the taste of the artist; and it is pretty much so with the various mould- ings which compose the cornices, capitals, &c.
Pilasters are square columns (parallelopipeds) sel- dom detached, but fastened to the wall or wainscot, and projecting nearly a third or fourth of a module. In other respects, their ornaments, capitals, base, and all their proportions are regulated by the rules of the order they belong to.
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