This section is from the book "Carpentry for Boys", by J. S. Zerbe. Also available from Amazon: Carpentry for Boys.
See Queen Post.
120. Trammel. - A very useful tool for drawing ellipses. It comprises a cross, A, with grooves and a bar, B, with pins, C, attached to sliding blocks in the grooves, and a pen or stylus, D, at the projecting end of the bar to scribe the ellipse.
121. Turret. - A little tower, frequently only an ornamental structure at one of the angles of a larger structure.
122. Transom. - A horizontal cross-bar, A, above a door or window or between a door and a window above it. Transom is the horizontal member, and if there is a vertical, like the dotted line B, it is called a Mullion. See Stile.
123. Valley Roof. - A place of meeting of two slopes of a roof which have their sides running in different directions and formed on the plan of a re-entrant angle.
 
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