Priestley set out on his career with the highest ideal of his calling; indeed to him the office of a Christian minister was the most honourable of any on earth, and he had no other ambition than to distinguish himself by his application to the studies proper to that profession. That he laboured unselfishly and with no idea of place and preferment is certain from the circumstance that he suffered from a physical disability which he must have recognised could not but tell strongly against his chance of worldly success. He had an inveterate stammer which, at times, made preaching as irksome to him as it was trying to those who had to listen to him. In spite of many and repeated attempts he never wholly overcame this trial. And yet nothing is more characteristic of him than, as he reviewed his career in the evening of his life, he should see that, like St Paul’s thorn in the flesh, his impediment had not been without its use. “Without some such check as this,” he says, “I might have been disputatious in company, or might have been seduced by the love of popular applause as a preacher; whereas, my conversation and my delivery in the pulpit having nothing in them that was generally striking, I hope I have been more attentive to qualifications of a superior kind.” The thorn in the flesh was probably not without its use in other ways. It probably drove him to literature. If he had none of the graces of pulpit oratory, he had at least the gift of facile composition. If he could not hope to move men’s minds by oral appeals, he might aspire to sway them by the power of the pen.