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operations, we shall not hesitate in acknowledging 

 that they are amply sufficient, to effect the great and 

 wonderful change which, in the course of time, has 

 been produced at the mouth of the Po, without refer- 

 ing it to the alluvion brought down by the current of 

 that river and its auxiliary branches. 



In support of this, J. might add many interesting 

 facts, all tending to prove that the operations of the 

 winds and rain, on the cultivated grounds in the vici- 

 nity of the mouth of the Po, and the direct labours of 

 man immediately upon the new formed district, have 

 been the principal cause of the increase and extension 

 of the delta at the mouth of that river. 



It may be thought by some, however, that these two 

 latter causes, are altogether insufficient, if they exist, 

 to produce that difference ; and it may even be asked 

 from whence came the materials to cause this surpris- 

 ing change, since they are no where missed ? 



If I might be allowed to compare great with small 

 things, or to reason from small to great things, I 

 would answer by the following fact. 



We observe on some of the alluvial plains of the 

 northern or eastern states, sometimes in the open 

 ground, but more frequently in the depth of forests, 

 a cluster of mounds, or pyramids of sand, which, in 

 some instances, have the resemblance of a miniature 

 encampment. They are the result of the labour and 

 perseverance of a large species of the red and black 

 ant, probably the Formica media rubra, and Nigra, 

 of Ray, and which, in the warm seasons, when they 



