50 TOWN PLANTING 



effects of the searching air to which narrow 

 streets were subject, so that, while there 

 was no space for trees, there was also less 

 necessity. Wide streets, on the contrary, are 

 hotter, and require the shade of trees to cool 

 them, and, as in the case of London, which 

 has so far done to a great extent without 

 trees in its streets, not only are modern streets 

 compulsorily wide, but the enormous increase 

 in metropolitan buildings renders every sani- 

 tary question one of importance; and the 

 chemical properties of trees, as shown by ex- 

 periment, give them an important standing 

 on that ground, irrespective of ornament or 

 the pleasure they produce." 



