Volume 13 Number 12 



The Plant World 



A Magazine of General Botany 

 DECEMBER, 1910 



AN EFFECT OF CEMENT DUST ON ORANGE TREES. 



By George J. Peirce. 



As this country becomes more thickly settled, the various 

 occupations of the inhabitants inevitably press more closely 

 upon each other, overlapping and even interfering with one 

 another, as the population and the occupations grow. Thus, 

 the town encroaches upon the coimtry, the factory on the resi- 

 dential section. The wastes of civilization spread much further 

 than those directly engaged in the production of those wastes. 

 Thus, the smoke of cities spreads out over the surrounding coun- 

 try, dimming the sunlight and vitiating the air, impairing the 

 fruitfulness of fields and orchards, as well as destroying the com- 

 fort of existence. 



The disposal of sewage we plainly recognize as one of the 

 duties of a civilized community, and in many cities the checking 

 of the soot nuisance, commonly spoken of as smoke ordinance, 

 is plainly recognized ; but how few realize that the smoke nuisance 

 is not fundamentally a problem of the disposal of the solid wastes 

 of our commercial and domestic fires, but rather of the empound- 

 ing of those gaseous wastes, which, when freely discharged into 

 the air poison it for long distances. 



Other forms of industry discharge their liquid, solid, and 

 gaseous wastes under only partial control, so far as laws and 

 ordinances and the will of the people go, the only control being 

 an economic one; for when the loss of waste becomes unprofitable, 

 then, and then only, are steps taken to prevent or reduce it. 

 When it is considered to be cheaper to let the waste go, although 

 it may be of an almost finished product, no steps are taken to 



