An introduction to horology and timekeeping, including links to the history of timekeeping, as well as some resources for projects for children to help teach them some concepts: https://www.jomashop.com/academy/article/a-history-of-horology-clockmaking-and-watches/ (Our thanks to the Garcia family for this link, and especially to Emilia who used this link and many of the websites we recommended on this page for her historic inventions project for her Social Studies class!)
GENERAL WATCH LOOK-UP RESOURCES AND RESEARCH TOOLS:
A remarkable tool to research most American pocket watches: https://pocketwatchdatabase.com (Please note that due to the extensive database here, some of the information is extrapolated from things that are known but have not been directly observed. Always verify your information.)
A great resource for early colonial-era pocket watches, including American, English, Dutch, and Swiss, put together by Richard Newman and including recommended reading on particular makers: https://www.colonialwatches.com/all-watches
Jones & Horan's own sales archives: www.archive.jones-horan.com Prices and basic info can be had on items sold in auctions back to 1992, basic images and info is available on items from auctions 1996-2004, and full information and photos are available on lots in auctions from 2005 to the present.
ORGANIZATIONS FULL OF RESOURCES (SOME THROUGH MEMBERSHIP):
NAWCC, a community of watch and clock collectors with extensive records, research, education, venues for information exchange, etc: https://nawcc.org
Antiquarian Horological Society, with extensive research on the art and history of time measurement: http://www.ahsoc.org
Since 1858, the British Horological Institute has been a source of news, education and more: http://bhi.co.uk
Hodinkee, a robust online magazine featuring in-depth reviews, critiques, and reports on watches of particularly high quality: https://www.hodinkee.com
Worn and Wound, for news and blogs on value-driven watches, the most beautifully-designed and well-crafted timepieces, regardless of price point: https://wornandwound.com
Watches by SJX, Asia's leading journal dedicated to fine watchmaking, covering mainly wristwatches but with some focus on pocket watches: https://watchesbysjx.com
Revolution Watch Magazine celebrates the craft, culture and joy of watches and watchmaking through a dozen international editions and its website: https://www.revolution.watch
RESEARCH SPECIFIC TO A PARTICULAR WATCHMAKER OR BRAND:
Resource for all things Elgin by Jeff Sexton: https://www.elgintime.com/ We previously recommended Wayne Schlitt's excellent website, http://elginwatches.org , but it appears to have been removed from the web.
Another Elgin pocket watch serial number lookup: https://www.elginnumbers.com/ powered by Strickland Vintage Watches
Historical pocket watches from Glashütte by A.Lange, A.Schneider, M.Grossmann, and J.Assmann (in German, but with a Google translater to change the language on the site): https://glashuetteruhren.wixsite.com/glashuetteruhren
Exhaustive resource on Glashütte watchmaking (in German, but with a Google translater to change the language on the site): https://www.glashuetteuhren.de
A handy Hamilton database - no membership needed!: https://www.nawcc.org/research/company-records/hamilton-serial-number-search This database includes Hamiltons Serial numbers from 1 to low 800,000s; it does not have serial numbers between low 800,000s and 3 millions. It also does include a lot of the alpha-numeric numbers like on 992B or 4992B, for example.
A guide to Illinois Watch Co. size 12 watches: http://www.illinoiswatchguide.com (This site unfortunately no longer displays, but archived versions of it can still be viewed through the www.webarchive.org utility)