336 JAMES BICHExXO FRANCIS. 



viding suitable sluiceways for drawing the water out in dry seasons, 

 to be used for power at Lowell and Lawrence when the Merrimac 

 River was low. This advantage was secured in part at once, and 

 appliances were soon constructed for regulation, by which the water 

 could be retained or supplied at need. 



This arrangement was continued till 1889, when the Lake Com- 

 pany was transferred to a syndicate of New Hampshire manufacturers, 

 who naturally were more in accord with their own Legislature, with 

 relief from taxation of the Massachusetts proprietors and little change 

 in the conservative use of the water ; whilst now slight irregularities 

 of flow could be readily met by the improved means of pondage and 

 distribution of water at Lowell and Lawrence. 



Under the new proprietorship of the Locks and Canals Company it 

 was necessary that all the mills should, as near as possible, have the 

 proportion of water to which they were entitled. To effect this Mr. 

 Francis designed and constructed the Northern Canal, a very large 

 and independent feeder, with branches to all the other canals. This 

 work was begun and finished with thoroughness and economy, and 

 still remains, with its massive walls and gates, its ample dimen- 

 sions and permanency of construction, as a worthy monument to its 

 engineer. 



As it was of great advantage to be able to shut and open the head 

 gates with but little manual labor, this was effected by a turbine 

 wheel moving nuts on vertical screws attached to the gates. With 

 the construction of the fire service reservoir, ample power was readily 

 available from the mains for hydraulic lifts, which are now applied to 

 other head gates. 



The head gates of the old canal consisted of the usual slide gates 

 and a lock for the purpose of navigation. From the records of high 

 water of the last century, Mr. Francis was satisfied that the coping of 

 these locks was not hi^h enousfh to restrain a like freshet, and that it 

 would flow over, destroy the work, and sweep out the business part 

 of the city of Lowell. He therefore raised the walls of the lock, and 

 constructed grooves in them from its floor to a height well above the 

 freshet mark, and in the grooves he hung a solid timber portcullis or 

 slide gate not interfering with navigation. Two years after its com- 

 pletion (1850) Mr. Francis's expected freshet came, the flood was fast 

 approaching the danger height at the coping, the iron strap was cut, 

 and the gate fell ; and although the water continued to rise even above 

 the old mark, the city of Lowell was safe. The gate has now been 

 raised and set again. 



