When a fireplace smokes, it should be examined to make certain that the essential requirements of construction as outlined in this bulletin have been fulfilled. If the chimney is not stopped up with fallen brick and the mortar joints are not loose, note whether nearby trees or tall structures cause eddies down the flue. To determine whether the fireplace opening is in correct proportion to the flue area, hold a piece of sheet metal across the top of the fireplace opening and then gradually lower it, making the opening smaller until smoke does not come into the room. Mark at the lower edge of the metal on the sides of the fireplace. The opening may then be reduced by building in a metal shield or hood across the top so that its lower edge is at the marks made during the test; or the trouble can generally be remedied by increasing the height of the flue. OUTDOOR FIREPLACES Outdoor fireplaces range from simple makeshifts to elaborately equipped structures harmonizing with the architecture of the house. No one type will meet all conditions, but all types should be practical to use and yet not be fire hazards or eyesores. [Illustration: Figure 40.--A, A fireplace built for 30 cents, cash. One hundred and twenty bricks and six concrete blocks were picked up a few at a time along the road. One sack of cement was purchased, one-half of which was used for another job Sand was available on the site. B f Detailed drawings show dimensions of this fireplace. As the fireplace is ordinarily built, the material would cost about $5 and the labor from $5 to $10, depending on local conditions.] TYPES The tendency is to build too large an outdoor fireplace. Where only a little cooking is to be done occasionally in a small yard or at a picnic, several concrete blocks or stones set on the ground about 12 to 16 inches apart will serve. The shelf of an old refrigerator may be used for a grille. If permanence is desired, the walls should be laid in cement mortar and the fireplace should have a suitable foundation and a permanent grille. An end wall is recommended to prevent embers from being scattered by drafts blowing between the side walls. Smoke annoyance while cooking is lessened by making the fireplace long enough to permit a short chimney (fig. 40). [Illustration: Figure 41.--An outdoor fireplace built back of an inside fireplace and opening onto a paved terrace provides comfort in early fall.] A circle of stones laid loosely on the surface, larger stones set partly into the ground, or carefully laid masonry walls on a stable foundation may be used for campfires and small barbecue parties. A cast-iron pot with a lid can be buried in the ashes for baking. Pipe supports for pots and pans built into the masonry are a convenience; they can be homemade or purchased. Spits for roasting can be improvised or bought.