Corrado D'Agostini's book pays for itself - again!

It is nowhere near totally comprehensive, but it is still very useful - not least through the good images.

A french lister has a simple Darlot sleeve with the screw-in locking device found on the Universal Darlot and a few others in the 1860's.

Like everyone does, I checked what else was on offer from the same seller - you never know! There was a lens barrel with a Waterhouse stop, with no focussing track. The WHS had the central indentation for a small tab system on the stops.

Page 142 in Corrado's showed the right lens. The brass lens hood will have to be made-up, but I am guessing from given dimensions that I have the flange already.

I certainly wouldn't have taken the chance without the book!

Well this turned out to be surprise!

The two half lenses do match. I can understand that the seller didn't make the "connection" between the two halves, as the two have some "rattling" clearance.

The sleeve has added internal turned roughness and there are turned "lips" at the edges. Although there are no remnants of material or glue, this must have had a full velvet bearing to take up the slack and provide controlled friction.

But the biggest surprise was that it is not a Petzval (anymore?) but a symmetrical doublet! The thread depth and mounting rings suggest that this has always been the case. Darlot included a whole series of doublet pairs in their Universal set from around 1866.

The matching flange was listed by the seller just a few days after I BINed the 2 halves!