666 ON THE RELATION OF NATURAL SCIENCE TO ART. 
figured by aimlessly ornamented columns and cornices, unpleasantly | 
recalling the impure features of Rococo furniture and architecture. 
1 forget which French mathematician of the last century, in sight of 
the cupola of St. Peter’s at Rome, tried to account for the sense of per- 
fect satisfaction it gives to the eye. He measured out the curves of 
the cupola, and found that, according to the rules of higher statics, its 
shape supplies the exact maximum of stability under the given cireum- 
stances. Thus Michael Angelo, guided by an unerring instinct in the 
construction of his model (the cupola was not erected till after his 
death), unconsciously solved a problem the true nature of which he 
could hardly have understood, and which was even beyond the reach 
of the mathematical knowledge of his age. Apparently however 
there are several roots to this equation of beauty; at least, there is one 
other type, for which I quote the cupola of Val de Grace in Paris, 
which, if not as imposing, is quite as gratifying to the eye as Michael 
Angelo’s. sf 
It will be observed that in this case mechanical beauty becomes part of 
the art of architecture; and instances of this kind are daily growing more 
frequent, our modern iron structures being more favorable to its dis- 
play than stone buildings. In the Eiffel tower we see mechanical beauty 
struggling with the absence of plastic beauty. On this occasion it was 
probably revealed for the first time to many who hitherto had no op- 
portunity of experiencing its effect. It is certainly not wanting’ in the 
new Forth Bridge. There is no doubt however that in stone struc- 
tures too, together with much that pleases from habit or tradition, 
there are certain features which evidently attract through mechanical 
beauty—such as the outline of the architectural members of a building, 
or the gentle swelling and tapering of the Dorie column towards the 
top, and its expansion in the echinus and abacus; and there are others 
which offend a refined taste through the absence of this beneficial ele- 
ment, such as the meaningless ornamentations of the Rococo style. 
Even in organic nature mechanical beauty prevails to such an extent 
that it transforms many objects into a source of delight and admiration 
to the initiated, which are naturally repulsive to the untrained eye. 
Anatomists recognize it with pleasure in the structure of the bones, 
especially of the joints. In their opinion the ‘Dance of Death” out- 
rages good taste from more reasons than because it differs from the 
classical conception of death. Mechanical beauty was already per- 
ceived by Benvenuto Cellini in the skeleton, much to his credit; and 
but for our imperfect knowledge it would invest with its glory every 
organic form, down to the inhabitants of the aquarium, even under the 
very microscope. According to Prof. Schwendener, even plants are 
constructed on the same principle of fitness combined with thrift; and 
something of this we feel at sight of a spreading oak tree proudly dis- 
tending its vigorous branches towards air and sunlight. 
Again, our appreciation of the forms of animals, especially of noble 
