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CHAPTER VI.

OP THE DISTRIBUTION AND SITUATION OF BUILD-INGS WITHIN THE WALLS.

Their circuit being completed, it behoves us to considerthe manner of disposing of the area of the space enclosedwithin the walls, and the proper directions and aspects ofthe streets and lanes. They should be so planned as toexclude the winds : these, if cold, are unpleasant; if hot,are hurtful; if damp, destructive. A fault in this respectmust be therefore avoided, and care taken to preventthat which occurs in so many cities. For instance; inthe island of Lesbos, the town of Mytilene is magnificentlyand elegantly designed, and well built, but imprudentlyplaced. When the south wind prevails in it, the inha-bitants fall sick; the north-west wind affects them withcoughs j and the north wind restores them to health : butthe intensity of the cold therein is so great, that no onecan stand about in the streets and lanes. Wind is afloating wave of air, whose undulation continually varies.It is generated by the action of heat upon moisture, therarefaction thereby produced creating a continued rushof wind. That such is the case, may be satisfactorilyproved by observations on brazen aeolipylas, which clearlyshew that an attentive examination of human inventionsoften leads to a knowledge of the general laws of. nature.jEolipylag are hollow brazen vessels, which have an open-ing or mouth of small size, by means of which they canbe filled with water. Previous to the water being heatedover the fire, but little wind is emitted, as soon, however, as