95 



passes over the entire floor during the day from west to east, drying and 

 purifying practically the whole interior. 



The time when sunshine is most needed is when the sun is lowest, 

 from September 21 to March 21. The arrows in Fig. 43 represent the 

 extreme points which the sunshine reaches during this period, through 

 a four-foot window placed with the top 4 feet, 6 feet and 7 feet high, 

 respectively. With the highest point of the window at 4 feet, the direct 

 sun's rays would never reach farther back than 9 feet ; at 6 feet it would 

 shine 13^ feet back, and at 7 feet it would strike the back side of the 

 house a little above the floor. In very narrow houses a window not 

 higher than four feet above the floor would suffice. In houses deeper 

 than fifteen feet, however, the window should be placed even higher than 

 seven feet in order to obtain the most desirable conditions. 



Of SUN'S 

 DEC. 



/5V- 



FIG. 43. Sunlight reaches farther back into the pens when the windows are placed 

 high. The lines indicate the avetage direction of the sun's rays 



Small glass in window-sash seriously obstruct the light. Very large 

 lights break too easily and are expensive. Eight by ten is a good sized 

 glass to be used in a 12-light sash, making it about 3 feet 9 inches high 

 by 2 feet 5 inches wide. Use two of these for a house about 15 feet 

 square. Single sash are usually less expensive than double sash of the 

 same size, and the cost for the window frame is less. Single sash may 

 swing from the side, top, or bottom; from the middle vertically or hori- 

 zontally; or be made to slide to one side. (Figs. 44 A, C, D, E, F, 

 G, H.) 



There are advantages and disadvantages with each of the windows 

 shown in Fig. 44. Fig. 44- A swings from the side. Wall space must 

 be provided in order to swing the window around out of the way. This 

 method of swinging the window is the easiest and admits of the window 



