Suggested change:       TYPE and UNIT attributes to be allowed within

The TYPE attribute would allow different types of measurement to be tagged separately: for
example, one might want to be able to search/sort materials according to height, in order to
determine the amount of vertical space required for shelving.
One might want to try to match the extant archival materials with old inventories/catalogues
by the dimensions given in the latter.
One might want to encode the height, width, and depth of a precious object, as well as the
overall height, width, and depth of that object when enclosed in a protective container.
One might want to encode an unusual type of dimension, such as the diameter or radius of a
circular object.

The UNIT attribute would allow the unit of measurement to be encoded, and, by setting a
default, would save keyboard strokes.  It would also allow automated conversion from one
unit of measurement to another (e.g. from mm. to cm., or from inches to mm.).

As optional attributes, these would not alter the current encoding practices of those who
prefer not to use them.