From the reading desk
Which date belongs to an archival image?
Distinguish the date of an exposure, a depicted event, a print and a catalog record without inventing a precise historical date.
Write down what the date describes
A date can belong to the depicted event, the making of a photograph, the publication of a print or the later description of an object. Start by copying the field label as well as its value. A date without its label is easy to apply to the wrong event.
Keep the catalog’s qualifications
If a record supplies a range or an approximate attribution, preserve that wording in your notes. Do not turn a catalog range into a single day. In the Then & Found packets, the credited artifact date is shown with the original item record so you can check what is actually being dated.
Compare the artifact with its later life
The Hong Kong packet brings photographic production and later archival custody into the same investigation. The Morse packet distinguishes a demonstration from its later representation. Their essays explain the particular records; neither example is a rule that every archive dates material the same way.
Make a small evidence table
Use four columns: date wording, field or source, event being dated, and remaining uncertainty. Add a row for each relevant record. When two dates differ, first ask whether they describe the same event. Leave the disagreement visible if the supplied evidence does not resolve it.
Sources for the method
Prepared for Then & Found with AI assistance. Sources inform the methods; their institutions do not sponsor or endorse this guide.
Records to investigate
Photography and archival custody · 1868–1871 / 1981
John Thomson’s Hong Kong photographs
John Thomson travelled through China between 1868 and 1872, photographing streets, landscapes and people for audiences who would usually encounter them in print. Working with wet-collodion glass negatives meant carrying fragile equipment and preparing plates near the place of exposure. The tea-house view comes from Hong Kong during those journeys. Its later history is almost another journey: the negatives entered Henry Wellcome’s collection in 1921, and a contact print was made in 1981. The scene, the glass negative and the later sheet of photographic paper each have their own date.
3 books to explore · 3 records
Communications history · 1840s / 1900
Remembering Morse’s 1844 demonstration
On 24 May 1844, Samuel Morse sent a message from Washington to Alfred Vail in Baltimore over an experimental telegraph line. Annie Ellsworth had suggested the biblical phrase “What hath God wrought?” The event became an enduring scene in accounts of American invention. This illustration appeared much later, in Elbridge S. Brooks’s 1900 history of the nineteenth century. By then, telegraph networks had become everyday infrastructure. The picture shows how an earlier technical demonstration was remembered and staged for readers looking back over a century of change.
3 books to explore · 1 record
Statistical cartography · 1810s / 1860s
Minard measures the cost of the Russian campaign
Charles Joseph Minard published this graphic in 1869, more than half a century after Napoleon’s invasion of Russia. He turned the campaign into a geographical account of loss: a broad outward band narrows on the journey toward Moscow, and a dark return band dwindles further. Rivers, branches of the march and temperatures share the page with troop counts. It is an engineer’s retrospective construction from historical information. The result draws attention away from a sequence of victories and defeats toward the shrinking number of people who continued along the route.
3 books to explore · 1 record