Frederic Garretson

“ The long stretch of steadily flowing water above the dam, whose sloping edge only partly arrested its course, suggested the divided current of air thrown into the pipe of an organ. And, as the small column of air in the pipe, when thrown into vibration, is known to produce in some cases a perceptible tremor in the massive walls of a church, it is probable that a column of water half a mile in length, when in rhythmic vibration, would have a mechanical effect in proportion to its mass. ”

“ The stream is here over sixty yards wide, and the body of falling water produces a sound which can not be heard more than four hundred yards below, or half that distance above the dam. The impact of the fall is so trifling that it causes no perceptible vibration in the immediate vicinity. Yet, in the valley where Ellicott City is built, more than half a mile above the fall, the houses on either hill-side, which have foundations deep enough to reach the granite bed-rock, are subject to occasional vibrations which shake their walls and cause a continuous rattling of the windows. ”

“ THE valley of the Patapsco River, through which the Baltimore and Ohio Railroad passes, presents many interesting subjects to the student of physics and of geology. After passing the junction of the Washington branch at the Relay House, eight miles west of Baltimore, the alluvial plain gives place to a narrow valley with steep and wooded hills on either side, and walled with conglomerate or metamorphic rocks. ”