When I worked at the British Library it was a pleasure to help those researching historical artefacts so that they could identify old patents and trade marks.
I've just seen a book that came out of such research. It is Eye baths: an illustrated survey, by George Sturrock, who has been researching the field for thirty years. It was published in 2012.
It is arranged alphabetically by manufacturer and contains numerous colour illustrations of eye baths and packaging. Many were made of porcelain, it seems. There is a bibliography, and a table on page 214 of 36 patents arranged by applicant.
I'd have liked to have seen the "date" listed in this table explained -- was it date of application, or date of grant ? Both can seem important, and the former determines the length of the British patent term, and the latter the length of the US term. Also, I think there were patents mentioned in passing in the text which did not appear in the table and which were simply called a patent without giving the patent number, and I'd have also liked to have seen a full citation when the year of registration of trade marks was mentioned (which is frequently). These are minor quibbles. Once a librarian always a librarian, I am sorry to say.
I often used to see Mr Sturrock working away in the reading room on patents or trade marks. The result is truly a labour of love.
Other researchers on historical inventions that I recall were on croquet and revolving doors (both of which resulted in detailed books), ticket punchers, firearms, Indian topis [solar hats], and rat traps. It was a pleasure giving what help I could to all of them. It does seem to be men rather than women who get obsessed with a topic in this way.
One comment that George made that sounded useful was saying that eBay was a very good source of information, as sellers often provided good photos and patent or trade mark information.