On The Arch And Arcades.

variety of outline m the former ; a broader chiarscuro ; perhaps a greater scope for ornamentation ; for whilst both alike may present cornices , friezes , and shafts , upon which ornament may be lavished to any extent , the arcade alone affords a peculiarly favourable field for the ornamenfcisfc in its springing stones , keysfcons , archivolts , and spandrils . But besides these purely aasthetic

considerations , there is another poinfc of view in which the arcade may be looked upon Avith favour . Ifc is obvious that the arcade , and the vault , offer a system of construction which leaves the space they occupy freer , and more unencumbered than any other , not only because the use of the arch permits the points of support to be wider apart , but ; also becauseas I think may be easily

, shown , the points of support themselves may , cceteris paribus , be made , in respect to their area , or horizontal section , smaller in the case of ah arcade than in thafc of a colonnade . The reason is this : when the whole height of the aperture , or series of apertures , in a wall is given , the length of the shafts which support an arcade will necessary be less than their length Avheu they are charged

with a horizontal entablature , by tho radius of the arches supported . The stability of a pillar or shaft , or of any upright support , is , in the language of mathematics , directly as their ¦ diameter , or horizontal section , and inversely as their height or length . Therefore , in order to support any given pressure , whether it be that of an arch or of a

horizontal entablature , the less the height , the less may be the area of tho section of the pillars . This is no scientific delusion , but an exact , certain , mathematical truth , a truth Avhich may be recognised in the general adoption of the arch , whenever circumstances render ifc expedient to occupy as little space as possible by the supports . Thus it led to the substitution of arches instead of columns in the Christian Basilicas , for the internal supports of their roofs ; and the recognition of this truth no doubt led to the ultimately universal adoption of

arches instead of columns for the interior supports of medieval churches . It is true that the wider the arch , the larger must be the section of tho piers Avhich carry it ; but then the diminished length ( or height ) of the piers compensate for this , and the result is that an equal burthen is borne by less bulky supports whon arches are used instead of columns . I fear that in this disquisition

about the size of piers I may have been led away into details somewhat too technical ; forgetful that within these walls Ave are limited to the consideration of architectui'e as a fine art ; but unfortunately , in architecture , science and art are so intimately blended , or rather so indissolubly connected , that it is sometimes apparently impossible to skim over the surface of one Avithout dipping our

wings slightly into the other . One of the most beautiful applications of the arcade is in cloisters of the middle ages ; originating , I presume , in the irnpluvium , or perhaps , in the crypto-porticus of the Roman villa . The cloistered court became , in very early Christian times , appropriated as the atrium or forecourt of the Basilica , an interesting example of Avhich

survives at the Basilica of S . Ambrogio , in Milan . This cloistered court , * o Avell adapted to the solitary and contemplative habits of monastic life , soon became an essential feature in every monastery , and we find even thafc two such secluded courts Avere not unusual . At first , probably , mere sheds of wooden construction , they ultimately became objects on which the builders of old loved to display

all their power . Even as early as the tenth century , a portion of a cloister Avhich exists at Buys de Nelay ^ in France shoAvs much elaborate masonry . The Campo Santo of Pisa is a highly interesting arid very Avell preserved example of an arcuated cloister of the thirteenth centui'y , which , although now open , appears formerly to have been glazed , no doubt with a view to protect the frescoes and monuments with Avhich the interior Avas so richly decorated . This glazing was a luxury unknown in earlier cloisters ,

On The Arch And Arcades.

ancl seems to have been a natural consequence of thegrowth of tracery . I must not , however , dwell on this subject of cloisters ; the examples are too numerous to render ifc expedient for me- to present them to your notice here . Tefc they Avell deserve your careful study , as being one among the most beautiful of the applications of this principle of

construction . In civil architecture , the builders of the Middle Ages » were not slow to avail themselves of the arcade . The ' front of the doge ' s palace towards the piazzetta , Venice , presents an example of singular beauty ; and suggested , probably , those smaller glazed arcades which became one of the favourite modes of enriching the facades of

the palazzi in that city during the fourteenth and fifteenth centuries . To the former century is due , also , the noble arcade so Avell known as the Loggia dei Lanzi , in the principal piazza in Florence . This most original work marks an epoch in the hisfcory of our arfc ; for Ave recognise in it the commencement of the change which took placeso early in Italyand Avhich heralded the return to the

, ancient types . Michelangelo is reported by Yasari to have so enthusiastically admired this work by Andrea Orgagna that , when a general improvement of the piazza hi which it stands was contemplated , he declared thafc the most perfect mode of ornamenting it thafc he could devise Avould be to continue this noble arcade around ail the four sides of the square ; and I think there can be no doubt

that , had Michelangelo ' s conception been realised , one of the most magnificent architectural scenes in the world would have been the result . Some idea of the grandeur of this arcade may be formed by picturing to

the mind an arcade considerably higher than Somerset ; House , consisting of a single range of arches , forty-five feet high , from the pavement to the crown of the arch . The Campo Santos at Perrara , Bologna , and Milan , are examples of arcades very remarkable for their extent ; and , in the case of the latter example , especially worthy of study as an evidence of the applicability of terra-cotta

to the purposes of architectural ornamentation . It is iu the style of the earliest Renaissance , and overladen Avith a superabundance of the most intricate decoration , executed vrholely in brickwork , and designed in a quaint and original , but very effective manner . Those only Avho have endeavoured to execute buildings ivifch bricks of moulded terra-cotta can fully appreciate the

masterly dexterity with Avhich this most elaborate piece of work is carried out ; a dexterity Avhich is immeasurably beyond even the remotest conception of a London bricklayer . When the practical difficulty of moulding and casting in mere brick earth minute enrichments with the sharpness and force Ave here see , —the difficultytooof building

, , up and bonding together this multitude of details so closely and solidly that at the end of four hundred years the work should still stand iu excellent preservation—with these facts before us , we are constrained to admit that our artisans have si very great deal to learn before they can come up to the level of their ancestors . The other two cemeteries I have named are also noble

arcaded areas , offering valuable suggestions for similar structures in this country ; inasmuch as these covered avenues , while they afford a well-protected walk , offer most favourable positions for sculpture and for inscribed memorials .

A uniform , symmetrical arrangement of this nature would surely be better than the chaotic confusion of heterogeneous monuments which our open cemeteries usually present . ( To be continued . )

Ar00801

GLASGOW .- —Some brethren being dissatisfied with tbe appointment have got up an agitation , and meantime Sir A . Alison has suspended Bro . Houston ' s commission . Any one reading our notice of last week , will understand the nature and cause of the to opposition Bro . Houston .