This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol3", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
Every part and corner should be well lighted, and, so far as possible, especially in classrooms, the light should be admitted from left side of scholars. Other windows in classrooms should be regarded as supplementary or for ventilation. Right-hand light is best where left is impossible. Windows full in the eyes of scholars cannot be approved. Unless the tops of windows are more than 14 feet above floor, the plan should show no space for teaching more than 24 feet from window wall of any room.
Windows should never be provided merely for external effect, and glazing which diminishes light and is a trouble to keep clean or in repair must be avoided. A large portion of each should open for ventilation and cleaning. Sills of main lighting windows should not be more than 4 feet from floor ; and the tops of windows should, as a rule, reach nearly to ceiling, the upper portion being made to swing. Ordinary rules respecting hospitals should be remembered. Large spaces between window heads and ceilings are productive of foul rooms.
Skylights are objectionable, and not approved in school or classrooms. They are only allowed in central halls having ridge or apex ventilation. The colour of walls, ceilings, and all fittings in rooms should be carefully considered as affecting light; while the size and position of windows are especially important in bearing on the eyesight.
Windows should be properly distributed over walls of classrooms, so that every desk shall be sufficiently lighted. The glass line of the window farthest from the teacher should be on a line with the back of last row of desks.