Historical
Encyclopædia Britannica 1911
Article on Weights and Measures
The 10,000 year old inch
The History of the pound
Our own metre?
Cubits
Roman units
Feet
English Units
Germany and Austria
a really good reference for pre-metric German and Austrian units.
Prussian units
Scottish units
Indian units
Lengths
around the world
Other historical units
Printing units
The Bible
dates itself - book review