This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Free circulation of air cannot be obtained through a window when the shade is attached to the window cas- ing, as it partly fills the opening caused by lowering the upper sash. If the shade roller is attached to the top of the upper sash, the shade can perform its function without obstructing the opening when the sash is lowered. It only requires a shorter roller and a narrower shade. The roller brackets are attached in the usual manner, but, in order to have the shade hang vertically, a block, as wide as the lower sash frame, must be fastened under each bracket.
Ill: When the Upper Sash is Lowered the Shade is Out of the Way of the Opening
This arrangement also makes it much easier to put up a curtain, as the sash can be let down until the roller can be reached while standing on a chair. - Contributed by James M. Kane, Doylestown, Pa.