Nearly two years had elapsed between the publication of my first and the commencement of my second volume; and the causes must be assigned of this long delay. 1. After a short holiday, I indulged my curiosity in some studies of a very different nature, a course of anatomy, which was demonstrated by Doctor Hunter; and some lessons of chymistry, which were delivered by Mr. Higgins. The principles of these sciences, and a taste for books of natural history, contributed to multiply my ideas and images; and the anatomist and chymist may sometimes track me in their own snow. 2. I dived, perhaps too deeply, into the mud of the Arian controversy; and many days of reading, thinking, and writing were consumed in the pursuit of a phantom. 3. It is difficult to arrange, with order and perspicuity, the various transactions of the age of Constantine; and so much was I displeased with the first essay, that I committed to the flames above fifty sheets. 4. The six months of Paris and pleasure must be deducted from the account. But when I resumed my task I felt my improvement; I was now master of my style and subject, and while the measure of my daily performance was enlarged, I discovered less reason to cancel or correct. It has always been my practice to cast a long paragraph in a single mould, to try it by my ear, to deposit it in my memory, but to suspend the action of the pen till I had given the last polish to my work. Shall I add, that I never found my mind more vigorous, not my composition more happy, than in the winter hurry of society and parliament?