ARCHITECTURE. 



through a wall upwards, beginning at one 

 side of a room, and ending at the top of 

 a wall : its use is to warm the room, and 

 give passage to the smoke. That part of 

 the opening which faces the room is the 

 place where the fire is put, and conse- 

 quently is called the fire place : the tube 

 or hollow proceeding from the fire-place 

 upwards, for giving vent to smoke, is call- 

 f d the funnel, or Hue: the stone or mar- 

 ble laid level with the floor immediately 

 before the fire-place is called the hearth 

 or slab ; and the one under the fire-place 

 the back or inside hearth. The project- 

 ing parts of the walls on each side of the 

 fire-place, forming also parts of the sur- 

 face of the room, and standing at the ex- 

 tremities of the hearth, are called jambs : 

 the head of the fire-place in the surface 

 of a room, resting upon the jambs, is called 

 the mantle : the mantle, and that part of 

 the chimney resting upon it, forming a 

 part of the side of the room, and also the 

 whole side of the flue to the top, is called 

 the breast; the side of the flue opposite 

 to the breast is called the back ; and the 

 sides of the fire-place contained between 

 the jambs and the back are called covings. 

 'When there are two or more chimnies in 

 the same wall, the flues of which approach 

 very near to each other, the thin division 

 which separates one flue from another is 

 either called a partition, or a with ; that 

 part of the opening or horizontal section 

 opposite to the mantle of a fire-place is 

 called the throat ; and that turret above 

 the roof of a house, containing one or 

 more flues, is called the shaft. 



In stone walls, the most common dimen- 

 sions of the sections of flues are from 12 

 to 13 inches square, for fire-places about 

 3 feet wide in front; and those in brick 

 walls 14 inches by 9 inches. The area of 

 the section of the flue should always be 

 proportioned to the area of the fire usual- 

 ly put in the fire-place, that is, nearly 

 equal to the area of the horizontal section 

 of the fire itself, excepting at the throat. 

 The throat should be immediately over the 

 fire, and its horizontal dimensions in the 

 thickness of the wall should not exceed 

 4$, or a inches at most. The fuel grate, 

 or stove, should be brought as near to the 

 throat as conveniency may require. The 

 coving should be placed bevelling nearer 

 together at the back than at the jambs, 

 making an exterior angle with the front 

 of the jambs, and an interior angle with 

 the back, of 135 degrees each. The 

 back and covings forming the sides of the 

 fire-place should be of white materials, 

 such as white stone, or brick covered 

 with plaster, which are most convenient- 



ly put up after the house is built. Mo?' 

 metals are unfavourable for this pur- 

 pose. The top of the throat should be 

 quite level, forming an abrupt plane. 

 Some of the principles in the construction 

 of chimnies are very well ascertained, 

 others are not easily discovered till tried. 

 The more the air that goes into the flue 

 is rarefied, with the more force it will 

 ascend, and the higher the flue the great- 

 er also will this force be ; therefore the 

 fire should have as little vacancy on either 

 side as possible, and the flue, when con- 

 venient, should be earned as high as pos- 

 sible, and not have too wide an aperture 

 at the top The situation of doors in a- 

 room, the grate being placed too low, and 

 other things, often occasion smoke ; but 

 whatever be the cause of it, if once dis- 

 covered the evil may easily be remedied. 

 Circular flues are more favourable for 

 venting than those whose sections arc 

 rectangular. 



Vaults. A vault is an interior roof over 

 an apartment, rising in a concave direc- 

 tion from the walls which support it, 

 either meeting the vertex in a point or 

 line, as when the section of the arch is 

 Gothic ; or one continued arch from the 

 one abutment to the other, as when the 

 section is a semicircle, or a segment less 

 than a semicircle. 



The vertical sections of the intradoes 

 of vaults may be formed by an infinite va- 

 riety of curves ; but the most elegant 

 forms are either circular or elliptic ; which 

 forms of sections have been generally 

 adopted by the ancients of remote antiqui- 

 ty, by our ancestors throughout the mid- 

 dle ages, and by European nations at the 

 present day. We shall therefore confine 

 ourselves to those vaults which have their 

 extradoes of circular and elliptic sections. 



A cylindrical vault is a plain vault, the 

 figure of the extradoes of which is a por- 

 tion of a cylindric surface, terminating on 

 the top of the walls which support it in a 

 horizontal plane, parallel to the axis of 

 the cylinder. This is also called a cradle 

 vault. 



A cylindroidal vault is a plain vault, the 

 figure of the extradoes of which springs 

 from a horizontal plane ; its section per- 

 pendicular to those lines is every where a 

 semi-ellipsis, equal and similar through- 

 out, and its base is that of either axis ; or 

 it is sometimes a segment of an ellipsis, 

 less than a semi-ellipsis, having an ordi- 

 nate parallel to the axis for its base. 



A dome may be defined to be a vault 

 rising from a circular, elliptical, or po- 

 lygonal plan or base, such that all hori- 

 zontal sections of the intradoes are similar 



