A little personal experience may be worth repeating here. I was in a small, dilapidated general shop near the London Docks; the shopkeeper, fancying he detected in me a possible victim, drew my attention to a pair of celery glasses and began to descant upon their age, the difference between them and Cork or Bristol glass, and so on. After I had examined them carefully and satisfied myself that they were genuine--they were about 10 in. high with a very thin herring-bone cutting upon their flat-cut sides--I asked the price, which was absurdly high; then, disclosing my identity, I asked what he would say if I told him they were not genuine but only reproductions. To my utter astonishment, he exclaimed that he “must have been done.” The price--“if they were any use to me”--dropped considerably. Then I told him they were genuine, and sent a friend of mine, who is a collector, to purchase them, but not without the man endeavouring to obtain a price which was not only far above what he had asked me but considerably above the real value of the articles. I record this episode for the benefit of my readers who may be tempted to depend upon the seller’s opinion for a guarantee of the genuineness of their “finds.” Speaking generally, the ordinary shopkeeper’s knowledge is of the most superficial type and should never be relied upon, while, of course, his interest lies entirely in one direction. Research fails to throw much light upon the glass factory of Londonderry, nor is it easy to find pieces bearing indisputable proof of their origin. But it is a fact that in 1820 one John Moore transformed a sugar establishment in that city into a glass factory and, with his son, carried on the manufacture until 1825. Then a prohibitive duty stopped it. It is possible that only the black ale bottles were manufactured there. As for the glass exported from Londonderry to America, it is difficult to determine whether it was manufactured in that city or merely exported thence. The latter is the more probable, since by the Act of 1746 a duty of 9s. 4d. was imposed on every cwt. of material used in making Crown plate, flint, and white glass in Ireland, as against a duty of 2s. 4d. per cwt. in England, from which it will appear that Ireland in those days had no great incentive to manufacture glass in opposition to England. It is almost impossible to obtain authentic examples of the work of individual Irish factories. Nor can one state with any degree of certainty that a certain pattern, cutting, or style is identified with any one factory or another. Both the Waterford and Cork glass firms came from England, and brought with them English workmen. Hence it is pretty certain that the designs and styles adopted by them were replicas of those utilised in England, and not peculiar to Ireland or copies of ancient Irish relics. So, too, with the ornamentation.