Those ancient builders wrought cunningly with their material.  The bricks are fashioned and fixed to last for all time.  Exposed to the icy winds of a Lombard winter, to the fierce fire of a Lombard summer, and to the moist vapours of a Lombard autumn; neglected by unheeding generations; with flowers clustering in their crannies, and birds nesting in their eaves, and mason-bees filling the delicate network of their traceries—­they still present angles as sharp as when they were but finished, and joints as nice as when the mortar dried in the first months of their building.  This immunity from age and injury they owe partly to the imperishable nature of baked clay; partly to the care of the artists who selected and mingled the right sorts of earth, burned them with scrupulous attention, and fitted them together with a patience born of loving service.  Each member of the edifice was designed with a view to its ultimate place.  The proper curve was ascertained for cylindrical columns and for rounded arches.  Larger bricks were moulded for the supporting walls, and lesser pieces were adapted to the airy vaults and lanterns.  In the brickfield and the kiln the whole church was planned and wrought out in its details, before the hands that made a unity of all these scattered elements were set to the work of raising it in air.  When they came to put the puzzle together, they laid each brick against its neighbour, filling up the almost imperceptible interstices with liquid cement composed of quicklime and fine sand in water.  After five centuries the seams between the layers of bricks that make the bell-tower of S. Gottardo at Milan, yield no point of vantage to the penknife or the chisel.

Nor was it in their welding of the bricks alone that these craftsmen showed their science.  They were wont to enrich the surface with marble, sparingly but effectively employed—­as in those slender detached columns, which add such beauty to the octagon of S. Gottardo, or in the string-courses of strange beasts and reptiles that adorn the church fronts of Pavia.  They called to their aid the mandorlato of Verona, supporting their porch pillars on the backs of couchant lions, inserting polished slabs on their facades, and building huge sarcophagi into their cloister alleys.  Between terra-cotta and this marble of Verona there exists a deep and delicate affinity.  It took the name of mandorlato, I suppose, from a resemblance to almond blossoms.  But it is far from having the simple beauty of a single hue.  Like all noble veined stones, it passes by a series of modulations and gradations through a gamut of associated rather than contrasted tints.  Not the pink of the almond blossom only, but the creamy whiteness of the almond kernel, and the dull yellow of the almond nut may be found in it; and yet these colours are so blent and blurred to all-pervading mellowness, that nowhere is there any shock of contrast or violence of a preponderating tone.  The veins which run in labyrinths of crossing, curving, and contorted lines all over its smooth surface add, no doubt, to this effect of unity.  The polish, lastly, which it takes, makes the mandorlato shine like a smile upon the sober face of the brickwork:  for, serviceable as terra-cotta is for nearly all artistic purposes, it cannot reflect light or gain the illumination which comes from surface brightness.