In 1859, Armstrong contributed £1200 (in the region of £50,000 in today's money) for the construction of a new lecture theatre for the Lit & Phil Society in Newcastle. He, and his father before him, had had a long association with the Lit & Phil and he served as its President for many years. Given his generous contributions to the provision of its lecture facilities, it is perhaps not surprising that Armstrong held strong views on how they were used. In 1883 he wrote to the committee of the Society, expressing his displeasure at the subject matter of a recent lecture on an economic issue:
I am quite at a loss to understand how the Committee of the Society can have been induced to grant the use of the Lecture room for a discourse on such a subject as the “Unearned Increment”. It appears to me that they might just as well have permitted a lecture on the proper functions of the clergy, or on the disestablishment of the church, or on the progress of rationalism, none of such subjects would have been more calculated to stir up disaffection in the Society than that which has been countenanced by the Committee & expounded by an ecclesiastic member of the Society.
I would fain hope that the action of the Committee in this case has arisen from inadvertence but as President of the Society I must be allowed to say that I most strongly deprecate the introduction of lectures upon any controversial subjects which are neither literary nor philosophical in their nature. 14