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ought to be paid to admitting air, and to its effects 

 on the hygrometer. In cloudy, wet weather, short 

 fires are to be put on in the morning, so as to raise 

 the heat nearly 10 degs. above the night temperature, 

 and a little air admitted both at front and back of the 

 house, taking care to keep plenty of water on the 

 pipes ; for a strong fire-heat, accompanied by a brisk 

 circulation, will be found very injurious, if not coun- 

 teracted hj moisture. In bright weather, equal at- 

 tention is necessary ; for, if a great deal of air is ad- 

 mitted to keep down the heat, it is impossible to keep 

 the atmosphere sufficiently moist, consequently the 

 vines suffer. Air ought to be admitted not so much 

 to keep down the heat as to keep a current of fresh 

 air in the houses ; and small openings at front and 

 back are quite sufficient for that purpose. Vines will 

 seldom be hurt by sun-heat, if surrounded by a pro- 

 perly moistened atmosphere ; but to retain this in 

 dry, hot weather, the utmost vigilance is necessary. 

 As, then, there is but little heat in the pipes, they 

 ought to be kept deluged with water ; indeed, the re- 

 turn-pipes should always be laid in gutters, so that 

 they can be kept covered with water when required. 

 Now, although strict attention must be paid to the 

 admission of air, it is not intended that the ventilators 

 are to be opened and shut always as a cloud passes 

 over the sun ; for, although the thermometer may be 

 kept pretty steady, it is impossible to keep the hygro- 



