Mungo was a living chronicle of the Presbyterian Church, or rather of the passing events in what he called the religious world. He was keeper of the hall for the meetings of the Society for the Propagation of Christian Knowledge, beadle of Lady Tester's Church, and one of the door-keepers during the sittings of the General Assembly.

Such a variety of official employments gave him every opportunity of acquiring early notice of what was going on, and enabled him to fill up the rest of his time profitably—for Mungo never lost sight of profit—as the following anecdote proves:—Mr. Black, the minister of Lady Tester's Church, was perhaps the most popular preacher of his day; and strangers visiting the church generally gave a trifle to the beadle to procure a seat. A gentleman had conformed to this practice in the forenoon, and returned to resume his seat in the afternoon, but was prevented by Mungo. The gentleman reminded him he had paid him in the forenoon. "O but," said Mungo, "I let my seats twice a-day."

During the sittings of the General Assembly, he contrived, in his capacity of door-keeper, to make the most of the situation, and pocketed as much of "the needful" as he possibly could exact by an embargo upon visitors. He was highly esteemed by a large circle of old ladies of the middle ranks, who eagerly listened to the gossip he contrived to pick up in the course of the day. He could inform them of the proceedings of the Edinburgh Presbytery—what had been done at the last, and what was forthcoming at the next General Assembly —whose turn it was to preach at Haddo's Hole on the Tuesday or Friday following—whether the minister would preach himself, or by proxy—whether John Bailie would be at the plate, or his son Tarn in the precentor's desk—with various other scraps of local news equally edifying and instructive to his auditors.

It has been rumoured that he made a regular charge for his visits ; and hence the inscription on Kay's Print of "Prayers at all Prices." By way of improvement in the art of ghostly admonition, the beadle sometimes ascended the pulpit of Lady Yester's Church, and held forth to the vacant benches. On one of these occasions, it is said Dr. Davidson happened to come upon him unawares—"Come down, Mungo," said the Doctor, "toom (empty) barrels make most sound," in allusion to the rotundity of his person, and his somewhat large paunch.

The gravity of his manner was well calculated to make an impression on the ignorant or the weak; and those who could appreciate his merits were greatly edified by his prayers and ghostly exhortations. There was a peculiar degree of solemnity about his features. The ponderous weight of his nether jaw gave a hollow tone, not only to his words, but even when closing on the tea and toast, a dram, or a glass of wine, it was excellently adapted to produce the effect—solemn.