Their brightness might unexpectedly attract certain dangerous occupants of these waterways."
Besides, it was the last day the Nautilus would spend in these waterways, if, tomorrow, it still floated off to the open sea as Captain Nemo had promised.
The great lakes, that were enlarged during the glacial period and in some cases wholly created--by the scooping out and damming up of the waterways and by piling glacial drift around their shores--have had some of their outlets raised to a higher level, and others have been created anew.
In combination they can divide the territory, visit every merchant and get larger orders at smaller cost. Supplies can be purchased more cheaply in large amounts, and shipments in car-load and train-load lots make possible special (sometimes illegal) concessions from railroads and from carriers on waterways.