70 
THE YOUNG SCIENTIST. 
disregarded. In art, as in nature, it is 
tlie group tliat is the ornament, and not 
the individual ; and this law must be ob- 
served by the designer. In clusters, 
festoons, etc., of fruit or flowers, the indi- 
viduals may be arranged at random, but 
the cluster or festoon itself must be of 
symmetrical proportion. 
This law of symmetry is so important 
that it has been stated that there is no 
form, or combination of forms, whatever, 
• that when symmetrically contrasted and 
repeated, cannot be made subservient to 
beauty — in fact, the whole grammar of 
ornament consists simply of contrast, 
repetition and series. I would again im- 
press upon the amateur designer the 
necessity of scrupulously avoiding an 
overloading of detail ; he should first of 
all consider utility, making detail merely 
a secondary consideration, endeavoring 
at the same time to so group the details 
or to provide against injury by the skilful 
adjustment of the relieved portions to the 
situation, or use of the decorated object. 
Taste in design, I need hardly say, is of 
l)aramount importance ; and no amount 
of mere mechanical skill can counter- 1 
l)alance the effect of a badly conceived ; 
design. Strange as it may at first sight j 
appear, it is nevertheless true, that in no j 
popular style of ornament have purely! 
natural details . ever yet prevailed. It is 
true that in all the great styles, the de- 
tails are largely derived from nature, but ' 
for the most part conventionally treated. 
A plant or natural object is said to be 
conventionally treated when the natural 
order of its growth or development has 
been disregarded. The distinction be- 
tween the natural and conventional, or 
ornamental treatment of an object, 
should be clearly understood. In Fig. 1 
the engraving represents an ivy leaf con- 
ventionally treated, and it will be seen, 
that though the scroll is composed of 
strictly natural parts, still as no plant 
could grow in an exact spiral direction, 
the scroll form constitutes the conven- 
tional arrangement. 
Every desig'n is composed of two parts — 
plan and details ; as in a bracket, the 
shape of the bracket is the plan, the deco- 
rations of the bracket are the details of 
the design, and these details may either 
cover the entire surface of the bracket, or 
only portions of it.* Decorations which 
Fig. 1. 
uniformly cover the entire surface of an 
object are usually called diapers, and are 
commonly composed of a series of the 
same ornament in a vertical, horizontal, 
or diagonal order. Diapers, as in Fig. 2, 
Fig. 2. 
are best suited for flat surfaces, and have 
the best effect when arranged diagonally. 
The majority of the ancient mosaics are 
diapers of a geometrical pattern. It ap- 
l^ears that the first principle of orna- 
ment is repetition ; take a moulding, for 
instance, where we have simply a meas- 
ured succesion in series of some one 
detail. 
The nine great styles into which orna- 
ment may be broadly divided may again 
be subdivided into ancient, mediaeval and 
