190 PURIFICATION OP THE ATMOSPHERE BY VEGETATION. 



to the welfare and activity of every order of beings, and which 

 would soon be destroyed, were the operations of any one of them 

 to be suspended. It is impossible to contemplate so special an 

 adjustment of opposite effects, without admiring this beautiful 

 dispensation of Providence : extending over so vast a scale of 

 being, and demonstrating the unity of plan upon which the whole 

 system of organised creation has been devised." 



294. And yet Man, in his ignorance, and his thirst for worldly 

 gain, has done his utmost to destroy this beautiful and harmoni- 

 ous plan. It was evidently the intention of the Creator, that 

 Animal and Vegetable life should everywhere exist together ; so 

 that the baneful influence, which the former is constantly exer- 

 cising upon the air, whose purity is so essential to its mainte- 

 nance, should be counteracted by the latter. Nothing is more 

 prejudicial, therefore, to the health of a large population, than 

 the close packing which too many of our cities exhibit; hundreds 

 of thousands of men, with manufactories of all kinds, the smoke 

 and vapours of which are still more injurious than the foul air 

 produced by their own respiration, being crowded together in the 

 smallest possible compass, with scarcely the intervention of an 

 open space on which the light and air of heaven may freely play, 

 and without any opportunity for the growth of any kind of vege- 

 tation, sufficiently luxuriant to give pleasure to the eye, or suffi- 

 ciently energetic to answer its natural purpose. For the close 

 confined air of towns is almost as injurious to plants as to 

 animals ; the smoke which is continually hovering above them, 

 prevents their enjoyment of the clear bright sunshine which they 

 require for their health ; and the fine dust, that is so constantly 

 floating in the atmosphere, covers over their surfaces, and clogs 

 up their pores. 



295. Hence the low stunted dingy vegetation, which the 

 squares and open spaces of some of our large towns exhibit, is of 

 little service ; but extensive areas fit for the growth of lofty 

 trees, are so beneficial in such situations, that they have been 

 called the lungs of large cities, so important is the purification 

 of the air which they effect. It is true that they may occasion 

 some degree of dampness in the immediate neighbourhood ; but 



