Some of his lecture slides and comments are reproduced below. An increase in the tax rate causes the tax base to decline.
Tax rate times the tax base is the tax revenue or tax yield.
For the indicated tax rate the revenue is therefore represented by the rectangular area shown on the graph. As the tax rate is increased the revenue first increases and then declines. Two different rates may yield the same revenue. If towns must balance their budgets, revenue equals spending. Increased market value of property, but this also depends on whether other towns lower rates.