I just wanted to add that on the last thread on CW I linked to earlier, the contributor to that thread has added some links (Live Auctioneer links to a few vases, some of which are marked/signed Mont Joye vases). The contributor says those have been 'documented to be harrach with depository pics and record book entries, But also can be found in early legras/MJ/SD catalog pages and marked as such is this styling'.(sic)
I would say speculatively that one theory (of many possibles) if this is true and they are exactly the same vases, could be that this indicates they were made at Harrach then signed subsequently by Legras (Mont Joye) and sold by Legras (Mont Joye). But I am also curious as to the contributors wording '...marked as such is this styling'. Were they exactly the same vases or just similar styling?
However, I also do not know if depository pics and record book entries would be sufficient to substantiate that they were made at Harrach as I don't know what records would be necessary to substantiate that it was their production of vases. If a 'record book entry' is a production log, then presumably that would be substantiation, although I would have thought original line drawings from the factory would be the only documetary proof that vases were made there? I don't know if 'depository pics' are substantiation. Presumably they would be, only if the rules for items going into the depository were that they were only to be items made on the premises. (although I may have misunderstood what the term 'depository' means in relation to glass houses.)
I'm questioning for two reasons 1) Truitt's volume 1 documents some known Stuart peacock eye vases as Harrach and 2) I think I have read somewhere that some vases were mistaken as Richardson's, as they were given as a collection by Richardson's and from Richardson's, but some turned out to be other makers.
I do appreciate that I have very limited knowledge of glass and I am probably not in the best position to be questioning

and I have never written a book, never mind one on glass, and I can appreciate it must be very difficult

m