SOME MYSTERY CABOCHONS

These cabochons look to be from the same company. They are glazed all over. There is no impressed mark. As Ivan has said this would indicate more inexpensive production methods. They all bear evidence of stilt marks. This indicates that each one was individually placed in the kiln.
I've been researching the Prosser Patent for the solidifying of powdered clay that dates back to 1840. It was bought by Minton Hollis (and others I presume) to produce buttons and of course tiles in the mid-1840's. This same method was used by Ruskin. It seems that later developments of the Prosser Patent method allowed up to 500 buttons to be made in the one batch. If anyone has more information about the Prosser process I'd be interested to hear from you.