1846.J 



THE CIVIL ENGINEER AND ARCHITECPS JOURNAL. 



231 



It is eajy to recognise a correspondence in the principles and effects both 

 in the painting and architecture of Venice. 



Pig. 2. 



That variety of tints, of forms, of colours, and of the manner of break- 

 ing and blending them into one another, which is seen, with one or two 

 exceptions, in the Venetian painters, was in itself extremely attractive; 

 but its merit of beauty and picturesqueness was fatal to all grandeur and 

 dignity. So in the architecture, there were such a richness, such an intri- 

 «acy, so many curves of contrary flexure (archi proteiformi), and, as it 

 would sometimes seem, such a positive avoidance of anything lil^e uni- 

 formity or along continuatiuo of lines, that, picturesque though it be, and 

 interesting for reasons already given, it was yet far removed from simpli- 

 city and grandeur of effect. All these highly ornamental qaalities were 

 rejected by the Roman and Florentine schools, which excelled in the grand 

 and imposing style; and those palaces of Rome and Florence, which have 

 (be national features most strongly marked on them, as the Farnese, 

 Strozzi, and Pitti, contrasted with those in Venice most remarkable for 

 their peculiarities, present the opposite characteristics of grandeur and 

 mere picturesque beauty as much as objects totally diOering from each 

 other possibly can do, 



III. 



Although the marked characteristics of these styles arose out of pecu- 

 liar times and circumstances ; yet it must be allowed that the details of 

 these edilices are attributable partly to tie amount of the labour bestowed 

 on them and, in a great measure, to the degree of artistic skill and know- 

 ledge of picterial effect possessed by the Italians. At a period happy for 

 art they united the painter with the architect. Dominichiuo, Raphael, 

 Michael Angelo, were the better able (as were also our Christopher Wren 

 and Vanbrugli) to impress some originality and power on their works, 

 from possessing this combination of taleut. Ornaments, showing great 

 attention to chiar' oscuro, and a knowledge of the artificies of contrasting 

 light with shade and producing relief, and executed with reference to the 

 distance at which they would be viewed, are well displayed in some of 

 (bedetaili of buildings in Italy, as well Roman as Italian-Glothic; although 



in a different, rather than, perhaps, to a less extent than that seen in the 

 elaborate enrichments of Gothic architecture. 



Thus in many of the Italian cornices,* as in the brick and terra-colta 

 ones in Padua and Ferrara, but especially (as being likewise of superior 

 material) in that to the Strozzi palace, there is such a union of boldness 

 and richness— and sometimes these qualities stand out so conspicuously 

 singly, that they make all the impression on the spectator which it is pos- 

 sible for such things to do ; deriving their etfects from bold projection, 

 breadth of shade, and judicious arrangement of surfaces ; and not these 

 members only, but the chimneys, which make such sorry figures on our 

 roofs, are remarkable for their beauty and the outline they offer against 

 the sky ; and tbe deep effective border ornaments and decoration to doors 

 and windows often receive all the character and importance of which they 

 are susceptible. 



Let any one compare this Strozzi cornice with any cornices in England, 

 designed on buildings of an equal size with that palazzo, and he will see 

 and lament the difference. The former has been accused of " projecting 

 beyond all authority" — by so doing it becomes a bold and spirited produc- 

 tion. In England, too often this feature, even in large public buildings, 

 where it is capable of being made imposing, and ought to be so, dwindles 

 into insignificance and meanness ; for their parts are seldom large and 

 definite enough ; but often too small and too confused ; no account is taken 

 of the point of view whence they are beheld ; and little attention is given 

 to increase as much as possible the effect of light and shade, by making 

 some parts prominent and deepening the recesses of others, as, for instance, 

 in the dentiles, and egg and tongue moulding. From neglecting this, those 

 portions of the cornice are often entirely lost in the open air to the eye, 

 and require, in order to be seen at all, to be brought within the bounds of 

 the architect's own room, or else to be viewed through a telescope. 



* " when they came to the cornices — the massive unbroten cornices of their palaces — 

 the littleness of the other parts is so completi ly lost, that it is evident they wore actuated 

 by the same feelings of unity and breadth titat lent so much value to the best works of 



the ancients I cannot refrain from calling the attention of the student to the 



cornices employed by the Florentine school, inasmuch as there is no member of a build- 

 ing from which it receives so great an assistance and effect as from the cornice. In the 

 best and most celebrated examples, such us the Strozzi and Pandollini palaces, and the 

 Picolomini palace at Sienna, whose court and staircase are of extraordinary beauty, the 

 cornice is proportioned to the whole height of tlie building, as the height of an order, 

 notwithstanding the horizontal subdivisions and small cornices that occur between th« 

 ground and ihe crowning members. Not less celebrated than those just meutioned, is 

 that of the Farnese paliice at Rome, which has always been considered one of the most 

 powerful architectural effort* of Michael Angelo."— Givilt's " Elements of Architectural 

 Criticism.'* 



A NEW THEORY OF THE STRENGTH AND STRESS 



OF MATERIALS. 



By Oliver Byrne, Professor of Mathematics. 



(Continued from page 167.) 



The work done in elongating a bar to its elastic limit, whose sectional 



area is one square inch, and length one foot, equal '" i ^^ ( 77 ) i sup- 



l 

 posing the limit to be expressed by the fraction i, ; in this case A L= 1 



The units of work done in elongating any other bar of the same material 

 as the last, whose length equal L, and sectional area equal A, t* its elastic 



limit,-=JM^ ^-j-^ 



(I \2 

 T ) 



elongated to their elastic limit, i "^I, ( T" ) '^ called the modulas of 

 Resistance, and may be written M^, and is sometimes called the modulus 

 of longitudinal Resilience. If the work of elongating goes on till fracture 

 is produced M^ the work necessary to cause fracture in a bar a foot long 

 and an inch square, is styled the modulus of fragility, so that My L A, will 

 express the units of work that will cause fracture, in Ihe same manner that 

 M- L A expresses the units of work to extend a bar to its elastic limit. 

 By-aod-by we shall explain what is underslood by the term Modulus of 

 Rupture in Transverse Strains. The modulus of fragility. My must not 

 be mistaken for the unit of tenacity, which is the number of pounds that 

 would tear asunder a bar one square inch in section. Length is not taken 



A L. It is evident that -r- is the same value as in 



' is the same in all cases with bars of the 



