His resons he spak ful solémpnely,
Sownynge alway th'encrees of his wynnyng.
(= He gave his opinions very ceremoniously / Always making known the amount of his profit)
‘Solempnely’ literally means ‘solemnly’, which in the 1300s meant something more like ‘ceremoniously’— the Merchant took himself , and opinions, very seriously (this ties in with his high horse-riding position.)
‘Sownynge’ refers to musical sound; we might translate the line into modern English by saying he was always bleating on about his profits— as any good merchant should.
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