What does this number measure?
A familiar reference at the half-millimetre scale. Pencil lead is generally a mixture of graphite and clay. The width of its tip depends on sharpening and wear; it serves here as a representative comparison.
Compare the stated dimensions
The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.
Source and limitations
Catalogue order of magnitude; a source is provided, but this measurement has not been individually audited.
Macroscopic view of a pencil's graphite tip; representative tip width.
Model not specified: Varies by period. Proposed historical date; an existing documentary source is linked but was not consulted for this date in this session. Do not interpret this reference as the manufacturing date of the illustrated specimen. Tip of a generic pencil; it does not allow a manufacturing date or precise model to be assigned. A universal year would be misleading.