Aren't these great. I dug them up back in the 70's when I was a treasure hunter. Actually I dug two of them up, the other I found covered in mud in an old derelict barn somewhere in Devon in the 70's - Holsworthy if memory serves me correctly. I found a brass thimble at the same time but it is missing in action somewhere in my collection. Probably in a box or a jug and will turn up again one day after I'm gone. They are blown into a mould and turned so as to remove any mould lines and then the top is applied as a separate operation. The base has a high 'kick up' so is not flat like later bottles. The imperfections are what make the bottles so appealing. They would have been sealed with a cork. I think I dug them from the mud at Colwick Lake in Nottingham when they were dredging it to landscape the area. Lots of Codd bottles came out of that mud, and all in great undamaged condition.