186 HOT-HOUSE OF SHUTTERS. [December. 



kindle the fires in time, to prevent the heat from being 

 lower than what has been mentioned, lest a severe frost 

 should take place, as then a considerable lapse ensues 

 before the fire has any effect; and if the wind blows high, 

 the result might be injurious, unless the house be very 

 close. 



OF SHUTTERS. 



The benefit of these in severe weather is of material 

 service, for the preservation of an even temperature in the 

 house during the night, when changes are not observed ; 

 but they ought never to remain on through the day, when 

 the fire can be properly attended to. If the front and the 

 lowest sash of the roof are covered with these, it is gene- 

 rally sufficient. They should be made of three-quarter 

 inch boards, closely grooved together, having a cross bar in 

 the centre, and one at each end and each side, which will 

 make them substantial. If they are frequently painted 

 with care, they will last many years. Snow ought not to 

 be allowed to lay on these while they are on the glass, for 

 reasons that we have assigned. See January and Feb- 

 ruary. 



Some adopt double panes of glass to supersede the use 

 of shutters, which they think are attended with considera- 

 ble labour, (at the most only fifteen minutes a day, while in 

 use.) The sash frame is made a little deeper, so as to 

 allow half an inch between the panes of glass. The one 

 is glazed from the out and the other from the inside. It 

 appears to answer the purpose tolerably well, but the glass 

 must be both fine and even on the surface, lest a lens should 

 be produced, which would scourge the plants. We are 

 almost confident that we have seen this effect in some in- 

 stances. There must be a small hole about an eighth of 

 an inch in both ends of each row of glass, to allow a cur- 

 rent to dry up the moisture that may arise. Double sashes 

 during the severe months are frequently used ; but shutters 

 are preferable to either. 



