Help with the lens - Museum

Greetings,

People from Museum of Science and Technology in Belgrade asked me for a help in dating their two Jamin Darlot lenses. If you can help with info on these it would be great!

1. Mon JAMIN DARLOT Sr-OPTn-Bte s.g.d.g. 14r. Chapon Paris No.6892
2.Mon JAMIN DARLOT Sr-OPTn-Bte s.g.d.g. 14r. Chapon Paris No.14915


Best regards,
Ugo.

...and the images (sorry!!)

My best,
Ugo.

First of all, it looks like both lenses are assembled incorrectly. The "cone centralisateur" is normally placed in the rear (facing the film) and the other lens group and hood are placed at the front of the barrel. From the lettering on the lens pictured without the lens board, it looks like it may date from 1860-1861 according to the Lens Vade Mecum. That's the stated date range that followed Darlot's purchase of the company from Jamin when the lenses had both names engraved. The lens has the engraving (Anciennement Monsieur) Jamin, indicating the firm was formerly of Jamin. The other lens may date from the about the same time, but I can't make out the engraving. It's worth noting that the Lens Vade Mecum has many errors and I think the Darlot and Jamin names may have been engraved on lenses for a longer period than one year--just because I've seen a lot of lenses engraved as such.

Thank you very much!!!!

the one pictured on the board is NOT assembled wrong. it is in "landscape" mode. there is a locking knob that you loosen and then remove the ("normal rear") air spaced elements barrel and all. then you shoot landscapes with just the cemented pair. for this landscape set up you are only using half of the lens. just one set of glass.

the other i am not sure about.

eddie