The _primâ facie_ mode of obtaining increased window light would be by widening the openings; but as this, if carried too far, would at once injure the beauty of the window and cause inconvenience in glazing it, the more usual course adopted was to increase the number. Hence the couplets, triplets, and more numerous groups of the Early English windows. These groups, when placed in a side wall and under a level roof-plate, would naturally assume the form of arcades of equal height; but when under a gable, an arched roof, or a vaulted bay, they increased in height towards the centre,--thus giving us the two most familiar forms of grouping. The sections of the jambs were arranged (as in the earlier period) in the manner best suited to the admission of light--care being taken externally to avoid deep shadows upon the glass, and internally, to disperse the light as readily as possible through the building. In domestic buildings, where windows have to serve the double purpose of admitting the light and facilitating external view, they were not usually grouped as above described, but were made wider in their openings, the unpleasant effect which might otherwise arise from it being obviated, and the glazing and opening of the window rendered more easy by the use of thin mullions or pillars dividing the window into two or more lights. This system offered advantages so obvious that it was very soon adopted for churches also; so that, instead of obtaining increased light, as heretofore, by the indefinite multiplication of comparatively small windows, it became customary now, _for the first time in the history of architecture_, to make windows of _any_ size which their position or utility might dictate; the whole end of a church and the entire bays of its flanks being occupied, if need be, by single windows.