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CHAP. III. 
OF THE THEATRE, AND THE MOST HEALTHY SITUATION 
FOR IT. 
AFTER the site of the forum has been determined, the next 
care is to select the most healthy spot within the limits of 
the city for a theatre; in which sports may be exhibited on 
days devoted to the celebration of sacred rites. For those 
who frequent them in company with their families, engaged 
by the interest they take in the representations, remain in 
fixed attention; whence it happens that the pores of the 
body are exposed to the effects of the atmosphere; which in 
the neighbourhood of marshes, or spots otherwise unhealthy, 
is charged with vapours prejudicial to the human frame. 
This inconvenience may be avoided if the situation be chosen 
with care and circumspection. It is no less necessary that 
the theatre be not placed with its concave part facing the 
south; because, from its peculiar form, the sun would heat 
every part alike and prevent the circulation of air; which 
becoming rarefied and heated, causes the evaporation and 
exhaustion of the corporeal juices. On these accounts 
unwholesome situations must be avoided, and healthy spots 
carefully selected. 
If the situation chosen for the theatre be in the side of a 
hill, the substructure will be formed with little labour; but if 
we are compelled by circumstances to build a theatre in a plain,