Help Needed to identify a lens from a Rochester Favorite 8x10

[John Fink Jr.]

I am trying to identify a lens from a Rochester Favorite 8x10 I recently purchased.
From what I can tell, there are no written or engraved markings of any kind. It has no discs or slots of any kind.
Definitely no shutter. It does have three glass elements.
It also has what appears to be a focusing knob which extends the front of the lens outward. Here are some pictures.

Any help with this lens would greatly appreciated.
As always, thank you for your wisdom!

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/432307_2572631081405_1423128769_32196431_2064497491_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/418277_2572631601418_1423128769_32196432_1178463548_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/422038_2572631881425_1423128769_32196433_1444990761_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/422644_2572632161432_1423128769_32196434_1784479072_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/431352_2572633241459_1423128769_32196437_229984584_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/420947_2572632321436_1423128769_32196435_1453186088_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/393831_2572674042479_1423128769_32196447_1596522750_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/420928_2572674402488_1423128769_32196448_963002626_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/428306_2572674642494_1423128769_32196449_1350820961_n.jpg

[Richard Rankin]

It's a petzval (re-purposed magic lantern lens). It doesn't look large enough to cover 8x10, though. How big is the image on the glass when you focus it at infinity?

Richard

[OldCrow]

looks like its off a magic lantern projector.

[John Fink Jr.]

Thank you one and all for your help!

[Steven Tribe]

One of the pictures seems to show that it has a permanent iris baffle mounted inside. This was sometimes done to stop buyers complaining about "way too much distortion at the edges of my lantern slides". You can remove this and increase the speed by a stop or use the baffle as a basis for mounting internal disc stops to "experiment" without having to look around for 25/50 speed film.