This site has a large focus on dive helmets but it also has some very nice information and photos on early scuba.
http://www.divinghelmet.nl/divinghelmet/Welcome.html
My favorite photo is a look a piece of trash taken from the ‘Elie Monnier’. You might recognize it from Cousteau's 'Par 18 metres de fond’.
http://www.divinghelmet.nl/divinghelmet ... nique.html