The Hereford missal gives no direction for censing the altar at that time.
York and Hereford ordered no censing at the offertory.
There is not the slightest doubt that the censing of things and persons was first practised as an act of purification, and thus became symbolical of consecration, and finally of the sanctification of the soul.
Exquisite ornament is seen in the triforium arcade, and between some of the arches in the transept are figures, especially finely carved, though much mutilated, known as the censing angels.