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chalk or marble. After polishing, the cornices are to be 
run along the springing: they are to be as slender and 
light as possible ; for, when large, they settle by their 
own weight, and are incapable of sustaining themselves. 
But little plaster should be used in them, and the stuff 
should be of uniform quality, such as marble-dust ; for 
the former, by setting quickly, does not allow the work 
to dry of one consistence. The practice of the antients, 
in arched ceilings, is also to be avoided; for their cor¬ 
nices are dangerous, from their great projection and con¬ 
sequent weight. Some cornices are of plain, others of 
carved, work. In small private rooms, or where fire or 
many lights are used, they should be plain, to allow 
of being more easily cleaned; in summer rooms, and 
exedræ, where the smoke is in such small quantity that 
it can do no injury, carved cornices may be used ; for 
white works, from the delicacy of their colour, are always 
soiled, not only with the smoke of the house itself, but 
also with that of the neighbouring buildings. The cor¬ 
nices being completed, the first coat of the walls is to be 
laid on as roughly as possible, and, while drying, the sand 
coat thereon ; setting it out, in the direction of the length, 
by the rule and square; in that of the height, perpen¬ 
dicularly ; and in respect of the angles perfectly square; 
inasmuch as plastering, thus finished, will be proper for 
the reception of paintings. When the work has dried, a 
second and afterwards a third coat is laid on. The sounder 
the sand coat is, the more durable will the work be. When, 
besides the first coat, three sand coats at least have been 
laid, the coat of marble-dust follows ; and this is to be so 
prepared, that when used, it does not stick to the trowel, 
but easily comes away from the iron. Whilst the stucco