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there is no rain, if the state of the atmosphere be moist. 

 2. It appears on the partition as well as the exterior 

 walls. 3. So also on pavements of brick or stone. 

 4. It is more copious in proportion as the walls are 

 thicker; the reverse of which ought to be the case, if 

 this hypothesis were just. If cold water be poured in- 

 to a vessel of stone, or glass, a dew forms instantly on 

 the outside: but if it be poured into a vessel of wood, 

 there is no such ap[)earance. It is not supposed, in the 

 first case, that the water has exuded through the glass, 

 but that it is precipitated from the circumambient air; 

 as the humid particles of vapour, ])assing from the boil- 

 er of an alembic through its refrigerant, are precipi- 

 tated from the air, in which they are suspended, on the 

 internal surlace of the refrigerant. — Walls of brick or 

 stone act as the refrigerant in this instance. They are 

 sufficiently cold to condense and preci})itate the mois- 

 ture suspended in tlie air of the room, when it is heavi- 

 ly charged therewith. But walls of wood are not so. 

 The question then is, whether air in which this mois- 

 ture is left floating, or that which is deprived of it, be 

 most wholesome? In both cases the remedy is easy. 

 A little fire kindled in the roon), whenever the air is 

 damp, prevents the precipitation on the walls: and this 

 practice, found healthy in the warmest as well as cold- 

 est seasons is as necessary in a wooden as in a stone 

 or brick house. I do not mean to say, that the rain 

 never penetrates through walls of brick. On the con- 

 trary I have seen instances of it. But with us it is only 

 through the northern and eastern walls of the house, 

 after a north-easterly storm, these being the only ones 

 wliich continue long enough to force through the walls. 

 — This however ha[)pens too rarely to give a just cha- 

 racter of unwholesomeuess to such houses. In a house, 

 the walls of which are of well burnt brick and good 

 mortar, I have seen the rain penetrate through but 

 twice in a dozen or fifteen years. The inhabitants of 

 Europe who dwell chiefly in houses of stone or brick, 

 are surely as healthy as those of Virginia. These 

 houses have the advantage too of being warmer in 



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