On Constructing Hot-house Flues. 25;J 



two inches from the walls, and supported upon single bricks 

 set one foot asunder, from centre to centre. It is thirteen 

 inches and a half in depth, being made of three courses of 

 common sized bricks (nine inches by four and a half,) laid 

 edgeways, and one foot broad, the covering and bottom of 

 the flue being formed of bricks one foot square. All these 

 bricks are two inches thick, and panelled one inch in depth, 

 the pannel occupying the whole surface of the brick, except 

 one inch all round it. The brick is thus only one inch thick in 

 the pannelled part, but being two inches thick at its sides, the 

 flue is as strong as if it had been built of common paving 

 bricks, at the same time that, from the thinness of the pan- 

 nels, the heat is allowed to pass into the house with the great- 

 est facility. The pannels are turned outwards, and those at 

 the top are found useful in steaming the house, which they 

 do well by being filled (when the flue is hot) with water, of 

 which their depth and area enable them to hold a large 

 quantity. Some additional heat-emitting surface is also 

 gained in each brick, by the sides of the pannels. No 

 difficulty was found in fabricating the bricks, they were 

 made in the usual way, and in common moulds, a piece of 

 wood slightly bevelled at the sides, of the dimensions of the 

 intended pannel, being previously nailed upon the block on 

 which the brick maker places his mould. Care was taken 

 that they were made of mild clay, as the softer the brick, 

 the more easy is the transmission of the heat. No parget was 

 allowed to be applied over the inside of the flue, the closeness 

 of the joints being secured by good workmanship solely. 

 Its advantages were immediately felt to be great ; with a 

 much smaller quantity of fuel it heated the house more 



