Mr. Jared Brooks who preserved a faithful scientific account of these earthquakes refers to that of the 7th of February, 1812, as the most violent endured at any period during their continuance. It occurred at 3 h. 15 m. in the morning and, as this gentleman's account says, "was preceded by frequent slight motions for several minutes; duration of great violence at least 4 minutes, then gradually moderated by exertions of lessening strength, but continued a constant motion more than two hours; then followed a succession of distinct tremors or jarrings at short intervals until 10 h. A. M., when, for a few seconds, a shock of some degree of severity, after which frequent jarrings and slight tremors during the day, once, at least in ten minutes. At 8 h. 10 m. P. M. a shock of second-rate violence, and during some minutes two others at equal periods, connected by continual tremor of considerable severity; the last shock was violent in the first degree, but of too short duration to do much injury. At 10 h. 10 m. P. M, after frequent considerable motions, the shock comes on violent in the second degree, strengthens to tremendous, holds at that about seven seconds, then trembles away, severe about five minutes; frequent tremors follow, and a shock of third-rate violence. The action then ceases for a time." With one more extract from Mr. Brooks, we shall conclude this account of the celebrated earthquakes of 1811. This is a table showing the number and relative value of all the earthquakes experienced here. It is preceded by a lucid explanation of the degrees of violence referred to in the table, and shows at a glance the number and intensity of the shocks. "_First-Rate._--Most tremendous, so as to threaten the destruction of the town, and which would soon effect it, should the action continue with the same degree of violence; buildings oscillate largely and irregularly, and grind against each other; the walls split and begin to yield; chimneys, parapets and gable ends break in various directions and topple to the ground. "_Second-Rate._--Less violent, but very severe. "_Third-Rate._--Moderate, but alarming to people generally. "_Fourth-Rate._--Perceptible to the feeling of those who are still and not subject to other motion or sort of jarring, that may resemble this. "_Sixth-Rate._--Although often causing a strange sort of sensation, absence, and sometimes gidiness, the motion is not to be ascertained positively; but by the vibrators or other objects placed for that purpose. TABLE.