It would . . . deepen the bed of the Tiber.
--Addison.
2. To make darker or more intense; to darken; as, the event
deepened the prevailing gloom.
You must deepen your colors. --Peacham.
3. To make more poignant or affecting; to increase in degree;
as, to deepen grief or sorrow.
4. To make more grave or low in tone; as, to deepen the tones
of an organ.
Deepens the murmur of the falling floods. --Pope.