“_1692, February 3d._—What I heard to-day I must relate. There is one Mr. Newton (whom I have very oft seen), Fellow of Trinity College, that is mighty famous for his learning, being a most excellent mathematician, philosopher, divine, &c. He has been Fellow of the Royal Society these many years; and among other very learned books and tracts, he’s written one upon the mathematical principles of philosophy, which has got him a mighty name, he having received, especially from Scotland, abundance of congratulatory letters for the same; but of all the books that he ever wrote, there was one of colours and light, established upon thousands of experiments which he had been twenty years of making, and which had cost him many hundred of pounds. This book, which he valued so much, and which was so much talked of, had the ill luck to perish and be utterly lost just when the learned author was almost at putting a conclusion at the same, after this manner: In a winter’s morning, leaving it among his other papers on his study table while he went to chapel, the candle, which he had unfortunately left burning there too, catched hold by some means of other papers, and they fired the aforesaid book, and utterly consumed it and several other valuable writings; and, which is most wonderful, did no further mischief. But when Mr. Newton came from chapel, and had seen what was done, every one thought he would have run mad, he was so troubled thereat that he was not himself for a month after. A long account of this his system of light and colours you may find in the Transactions of the Royal Society, which he had sent up to them long before this sad mischance happened unto him.” From this extract we are enabled to fix the approximate date of the accident by which Newton lost his papers. It must have been previous to the 3d January, 1692, a month before the date of the extract; but if we fix it by the dates in Huygens’s manuscript, we should place it about the 29th November, 1692, eighteen months previous to the conversation between Collins and Huygens. The manner in which Mr. Pryme refers to Newton’s state of mind is that which is used every day when we speak of the loss of tranquillity which arises from the ordinary afflictions of life; and the meaning of the passage amounts to nothing more than that Newton was very much troubled by the destruction of his papers, and did not recover his serenity, and return to his usual occupations, for a month. The very phrase that “every person thought he would have run mad” is in itself a proof that no such effect was produced; and, whatever degree of indisposition may be implied in the phrase “he was not himself for a month after,” we are entitled to infer that one month was the period of its duration, and that previous to the 3d February, 1692, the date of Mr. Pryme’s memorandum, “Newton was himself again.”