THE THEORY OF CITY DESIGN. 75 



same number of hours before noon will be a similar line on the 

 other side of the meridian line WOXP, that is to say, if 6 t is the 

 angle of inclination between the south line and the shadow, for 

 the hours before or after noon, then the shadows direction is, in 

 the former case 180° + t , in the latter 180° — 6 t . The shadows 

 will never lie outside the curves SS and WW, which are, there- 

 fore, the limiting curves of the solar shadows. 



Referring to the diagram it will be observed that there are 

 northerly shadows in the morning and afternoon, in the summer 

 interval between the equinoxes, i.e. between the 23rd September 

 and 21st March, but none northerly in the winter interval. The 

 shadows are respectively west and east at approximately the 

 following hours of the day, for the different periods of the year 

 opposite each. 



IV. — Solar shadows east and west (approximate) lat. 35° S. 



Dec. 22 Jan. 19 I Feb. 1 9 I Mar. 21 



Solstice. Nov. 24 j Oct. 24 f Sep. 23 



la., m. h. m. h. m. h. m. 



A.M. 



8-30 



8-10 



7-10 



6-0 



P.M. 



3-30 



3-50 



4-50 



6-0 



If, therefore, a rectangular building have its sides directed to 

 the cardinal points, then for six months of the year its southern 

 wall will never have direct sunlight ; so, also, the northern side of 

 an east and west street. Table V, shewing the length of time 

 the sun shines on the southern face of an E. — W. wall, brings this 

 out more clearly. 



V. — Length of time sun is south of east-west line, in either 

 fore or afternoon. Lat 35° S. 



Dec. 22 Jan. 19 Feb. 19 Mar. 21 



Solstice. Nov. 24 Oct. 24 Sep. 23 



h. m. h. m. h. m. h.m. 



3-40 3-10 1-43 0-0 



There is really no effective sunlight on the southern side of an 

 E-W building for practically seven months of the year. Obviously 

 the buildings and streets of a city should have as much direct 



