All stone before being laid should be free 

 from any dirt or foreign matter and, unless the 

 supply of stone is extremely limited, it is much 

 better to select individual stones of the size and 

 shape which will produce the required texture 

 of stonework than to endeavor to use the large 

 and the small stones as they are found. 



Stones which are cut or broken are usually 

 divided into two classes: (a^l Stratified; (bi 

 Unstratified. 



The examples of stratified stone are sand- 

 stones, Hmestones, and shales. Igneous rock, 

 granite, and lava are in the unstratified 

 group. 



Stratified stone (pi. XXV, fig. 5) is easier to 

 lay than the unstratified stone (pi. XXIV, fig. 5), 

 which requires a more careful selection to pro- 

 duce desired effect in actual construction. 



Stone texture is an elusive element in design 

 because so much depends on the skill of the 

 workmen. A camp stove or fireplace must be 

 practical in use, and it must be of appropriate 

 design in mass and texture. The texture of the 

 stone masonry is so frequently not well designed 

 (pi. XXIV, and pi. XXV, figs. 2, 4, and 6), that 

 its importance in the completed structure should 

 not be minimized. Many of these features look 

 like stone piles with no stability or like monoliths 

 of mortar and stone with no surface texture. 



Joints in stonework should be neat and ap- 

 proximately '/2 to ^/4 inch wide. The color of the 

 mortar used in the joints should blend with the 

 natural color of the stone. In well-constructed 

 stone masonry, the mortar is not conspicuous. 

 In any event, the mortar should not be colored 

 unless it is necessary to avoid unusually light 

 color which contrasts unnecessarily with the 

 color of the stonework. These joints should be 

 raked fairly deep in order to eliminate so far 

 as possible the effect of too much mortar, and 

 to produce the effect of a natural dry stone 

 wall. 



CHIMNEYS 



The chimney does not add to the attractiveness 

 of any fireplace or camp stove. In fact, it is a 

 rather unattractive feature which increases the 

 massiveness, and for this reason it should be 

 avoided whenever practical. A low chimney 

 is sometimes not entirely effective, and, on the 

 other hand, if sufficiently high to function satis- 

 factorily the chimney may dominate the unit. 



The chimney, when used, may range from the 

 simple funnel (pi. XXVI, figs. 9, 10, and 11) on 

 the "ice box" and "oil drum" types of camp 

 stoves to a definite masonry construction, as 

 shown in plates XI and XII. It is confined 

 usually to the camp stove. A low chimney may 

 sometimes be constructed on a fireplace of the 

 types shown in plates X and XI. This feature is 

 most essential where the fire hazard is very 

 great. 



The height of the chimney should be kept to 

 a minimum and may vary from 2 feet above 

 ground, as shown in plate X, to 6 or 7 feet, as 

 shown in plate XIII. 



When the fire hazard is much above normal, 

 the chimney should be provided with a damper 

 control, and sometimes with a spark arrester 

 (pi. XXII, fig. 3, and pi. XIII, fig. 3). 



If the spark arrester is not used, there is great 

 danger that the live sparks may be carried into 

 highly inflammable timber. The spark arrester 

 is a small mesh of woven wire screen in a frame, 

 held in place at the top of the flue by means of 

 prongs or clamps. It should be installed in such 

 a way that its condition may be easily in- 

 spected and its replacement made simple. 



The throat of the fireplace is that portion 

 leading from the firebox to the chimney flue. 

 In the regular indoor fireplace (pi. XXIII) the 

 opening of the throat is about equal to the area 

 of the flue and is the full width of the fireplace. 

 In the camp stove fireplace (pi. XII), here 

 discussed, the full width may not always be 

 obtainable, but the proper area should be 

 maintained, and so far as possible the width 

 of the throat should be greater than its height 

 (pi. XIII, fig. 3). 



The chimney flue should in every instance 

 be lined with a fire-clay brick or with some 

 other regular lining. The height of the chim- 

 ney, the size of the firebox, and the ashpit, as 

 well as exposure, and type of vegetation sur- 

 rounding the camp unit are important factors 

 in the control of the draft. In general the area 

 oi the horizontal section of a round or a square 

 flue from a single firebox should be not less 

 than one-tenth of the transverse vertical section 

 of the combined firebox and ashpit. An arbi- 

 trary minimum area for the flue might be 4 

 inches square. A rectangular flue should some- 

 what exceed the minimum area above stated. 

 In camp stoves with open fronts on the firebox. 



18 



