The problem
Fine cloth could not be washed in water without damage, so soiled garments were often simply discarded or crudely spot-treated.
The innovation
A process for cleaning garments without immersion in water — the ancestor of dry cleaning — patented by a New York tailor.
How it worked
The detailed specification was lost when fire destroyed the Patent Office records in 1836; what survives is the register entry and contemporaneous accounts.
Why it mattered
Jennings used the income to purchase family members out of slavery and to fund abolitionist organising.
The legacy
The earliest United States patent this archive can attribute to an African American inventor. Because the original filing burned, the record is documented rather than verified.
You use this today
Every dry cleaner's shopfront.
Sources
Restored X-patent index, patent 3306X (1821)
Primary recordThomas L. Jennings biographical record
Institutional record
Follow the invention
Multiple-effect evaporator
A sealed series of vacuum pans in which the vapour boiled off in one pan supplies the heat for the next, at successively lower pressures.
Automatic engine lubricator
A cup that fed oil steadily to the engine's moving parts using the engine's own steam pressure, while it ran.
Caesarean section in Bunyoro-Kitara
A European medical student, Robert Felkin, watched a caesarean performed in Bunyoro in which both mother and child survived, and published a detailed account of the procedure.