I'm not sure how to tell the difference yet between pressed/moulded and cut glass, but I presume that you are referring to the base when you say some surfaces may be cut? I've looked at the base closely and the cuts do not seem uniformly regular in shape or width. Is that an indicator of whether they could be cut?
Anne â€” An attempt to clarify:-
Most of the glass relevant to us is cut in one way or another, in fact, the only glass items I can see from this PC that are not cut are a Pyrex measuring jug, a Marmite jar, a milk bottle, a pavement light, and a Davidson dome flower block (and I had to check the dome, because sometimes they are cut, to level them up). All the handmade art glass I have on the shelves behind me â€” Webb, S&W/RB, Walsh, and Nazeing â€” have ground out pontil marks, so are technically "cut". All the rest of the pressed glass and the handmade Frank Thrower avocado set has either a cut rim or base. And the rest is traditional cut glass.
If you divide the manufacturing processes up into hot processes that take place before the glass goes through the annealing oven or lehr
, and cold processes that take place afterwards, it makes all this a lot clearer. There is no relationship between the two, and any combination of hot and cold processes are possible. So press-moulding, blowing with or without the assistance of one or more moulds, centrifugally spinning, altering the shape with formers, lampwork, iridizing, etc. are all hot processes, and can be combined with any cold process such as cutting to tidy up and/or decorate, enamelling, gilding, acid-etching, sand-blasting, etc.
And, to make life more complicated, a few objects go through this process again! For example, if you found an iridized bowl with a cut base that was also iridized, you would know that it had been re-heated after cutting, and, in effect, gone round a second time for iridizing.
Sowerby's classification above (13 cut and 74 moulded salts) is confusing. All their salts were press-moulded, many also cupped with formers. I suspect that all their salts were cut to tidy them up. What Sowerby meant was that 13 were decorated by cutting, the other 74 were either undecorated or mould-decorated.
The only parts of your salt that are definitely the original moulded surfaces are the inside ribbed base depression and the inside where the salt goes. All the other surfaces, including the chamfers around the edge, could have been cut. On glass this old look for a mirror-like surface that shows slight striations in the direction of rotation of the cutting wheel or disk. Sadly, on glass produced in recent years it is not so easy. I recall a few years back looking at some Jasper Conran Stuart cut crystal in John Lewis, and being horrified to find all these lovely cutting marks had been removed by intensive acid-polishing. I don't know why. Not only does it remove the unmistakeable signature of hand-cutting, but these striations help to break up the light when it falls on the piece, giving it added sparkle. I try to avoid such glass as I cannot help but think of it as defective, which makes selling it to clients who trust my judgement something of a problem.
Please let me know if you find my explanation confusing.