[ 292 J | 
vers within their bounds by dykes, 
and by cutting canals to let out the 
waters, will greatly aflift the ope- 
ration of vegetables, which would 
be infufficient to cleanfe the atmo- 
{phere of low countries, without 
this great caufe of corruption, ow- 
ing to marfhes, being removed. 
ExpLa- 
