This green glass was bottle glass and any left over at the end of a days production would have either been used up in this form or melted down at the begining of the next day for producing more bottles, 'dumped' glass, hence the term. The glass workers must have had time on their hand as it would not have been a five minute job to produce these weights, especially those that had the inclusions such as the 'flowerpot' and 'flower' designs, this I believe was achieved using baking powder. The most well known and largest glass manufacturer in Victorian times and later was that of Stourbridge but could have come out of any of the UK glass manufacturers. Has anyone ever compiled a list of UK glass manufacturers, in the commercial sense I mean, bottle manufacturing and domestic glass wares? Forgot to say, there are differences in these old weights, ranging from varying depths of green through pale blues to clear but beware, there are fakes on the market and these can usually be identified by being too 'clean', more regular surface with a smaller broken pontil whereas the genuine ones have a more irregular slightly 'wavy' or striated surface that look like 'rings' and the pontil looks like it's been smashed off and often contains black deposits in the crevices like sooty marks and also when stood on the pontil don't stand straight.