I'm sorry I don't have the book to check, but I didn't say 'they think it's opalescent'
I said I
think the glass would be called opalescent glass rather than opaline glass - I meant the description of the type of glass process/effect, rather than a trade name for the glass.
Opaline and opalescent are types of glass process/effect and can be from all different makers.
'Pearline' is a registered tradename for a line of Davidson's glass as far as I am aware (I hope I'm not confusing things further). i.e. 'Pearline' and opaline are not the same thing.
Someone will be along shortly who will be able to correct this if I'm wrong