VOYAGE TO MADAGASCAR, I53 



x\uthftandmg the high price of fuel, have 

 preferred their moving force to that of 

 faeams, and falls of water. The greater 

 part of water-currents experience contmual 

 variations by rain and drought. Water- falls 

 require dams and Jluices, which internipt 

 the navigation of rivers, and fometimes in- 

 undate lands valuable for agriculture. Be- 

 fides, water thus colleded, and rendered 

 ftagnant, difTufes throughout the countr/ 

 the feeds of infedlon, which produce pefti- 

 lential diforders, and occafion great mortali- 

 ty in fummer and in autumn. 



If, to all thefe inconveniencies, we add 

 the frequent and expenfive reparations ne- 

 ceflary for dykes, fluicesj and works under 

 water ; and refleft on the great danger of 

 feeing valuable eredions fwept away in a 

 \ moment by a fuddeti thaw, or inundation ; 

 we ihall readily comprehend the motives 

 which induced Meflrs. Watt and Bolton^ 



the 



