How Canal-boats are Raised. 83 



the water run down into the lock until the water 

 in the lock is on a level with that in the upper 

 canal. The upper door or gate is then opened, 

 and the boat floats out upon the upper level. 



Upper gate, B, is opened, and the boat enters upper canal. 



1 2. Where a canal passes through land which 

 is hilly or sloping, there are sometimes so many 

 locks as to resemble a flight of stairs, as shown 

 on the chart, in the middle-ground. 



13. Canal-boats going from Albany to Buf- 

 falo on the Erie Canal must ascend, as shown 

 in the drawing above ; so also on the Wei- 

 land Canal, from Lake Ontario to Lake 

 Erie ; and on the Canal by which steamboats 

 on their way from Montreal to Lake On- 

 tario avoid the rapids in the St. Lawrence 

 River. 



14. Welland Canal is the only route by which boats 

 can sail between Lakes Erie and Ontario, because the falls 

 (160 feet high) in Niagara River render navigation be- 

 tween these two lakes impossible by way of that river. 



