In general, copyright in photographs normally ends 70 years after the death of the photographer, so a 1910 image could well still be in copyright. Let's assume the photographer was born in 1885 (so the photo was taken at age 25), and lived to 90, dying in 1975. The photo will be in copyright till 2045. Indeed, it's possible, though extremely unlikely, that an 1890 photo might just still be in copyright.
I agree with the point about museums etc. who have copies of photos. Buying a collection of photos, even if curated and from a good source, doesn't automatically give you ownership of the copyright. That only comes if it was transferred in writing by the copyright owner.
As a canal book publisher, I'm always conscious of these issues!