Each year of his life at this period Faraday found himself becoming busier than the previous one. Another five chemical lectures (on the metals, well known and little known) were given before the City Philosophical Society during 1818, completing a course, extending over three years, of seventeen lectures on the chemical science, no mean accomplishment for a young man from twenty-three to twenty-six years of age. So much was his time now becoming occupied that we find a great falling-off in his letters this year, a falling-off not only in number, but also in length. The correspondence with Abbott, commenced six years earlier, practically comes to an end in 1818; there was not, it is necessary to mention, the slightest abatement in the warmth of affection of the two friends; it was that, to a great extent, perhaps, the correspondence had done its work, and what is undoubtedly the more powerful reason, our young scientist was beginning to find his time so well occupied with his favourite work that he could not devote enough of it to the writing of long letters. Abbott was yet, and always, sure of the heartiest hand-shake and the most unaffected welcome from one who to the end of his life was the staunchest of friends. On July 1st, 1818, Faraday read a highly interesting paper before the members of the City Philosophical Society, on "Observations on the Inertia of the Mind," in which he drew, in an able manner, an analogy between a state of the mind and what in the physical world is known as the inertia of matter. It may be of interest to note a few passages from this lecture to illustrate the thoughtfulness and thoroughness of Faraday's work at this time, and also to give an example of his early style as a lecturer. "Unlike the animated world around him, which remains in the same constant state, man is continually varying, and it is one of the noblest prerogatives of his nature, that in the highest of earthly distinctions he has the power of raising and exalting himself continually. The transition state of man has been held up to him as a memento of his weakness; to man _degraded_ it may be so with justice; to man as he ought to be it is no reproach; and in knowledge that man only is to be contemned and despised who is _not_ in a state of transition.... "By advancement on the plain of life, I mean advancement in those things which distinguish men from beasts--sentient advancement. It is not he who has soared above his fellow-creatures in power, it is not he who can command most readily the pampering couch or the costly luxury; but it is he who has done most good to his fellows, he who has directed them in the doubtful moment, strengthened them in the weak moment, aided them in the moment of necessity, and enlightened them in their ignorance, that leads the ranks of mankind....