The contention between Mansell and the anti-monopolists was above all warm about the year 1623, on the occasion of the renewal of his patent for another fifteen years, and the ‘New Patent,’ the ‘Reasons against the same,’ Mansell’s ‘Defence’ and his ‘Motives and Reasons,’ and finally the ‘Answer’ to this last, followed in quick succession. All these documents and pamphlets are reproduced by Mr. Hartshorne; they form indeed an important source of information for the history of English glass. From them we learn that Mansell, after many failures elsewhere and the expenditure of many thousand pounds, first at Newcastle successfully made window-glass with the native coal; that the clay for the pots was at the commencement brought from Staffordshire, but that as the English clay proved unsatisfactory, he obtained a better material at infinite cost ‘from beyond Roan in France,’ and finally from ‘Spawe in Germany.’ At the time he was writing he indeed protests that he had already sunk £24,000 in his ventures. The precise position of Mansell after the expiration in 1638 of the second term of his patent is somewhat obscure, but he seems to have steered well among the troubles of the time and to have maintained his monopoly. At the period in question, he tells us he was producing ‘Ordinary Drinking Glasses’ for wine and for beer at four shillings and half a crown a dozen respectively, as well as mortar-glasses[244] at one-and-fourpence a dozen. He was at the same time making beer and wine glasses of crystal (these were from two to three times as dear as the last), beside looking-glasses and spectacle-glass plates in rivalry with the Venetians; finally, with English materials, window-glass and ‘green-glasses.’ There is nothing in all this, or indeed in any of these patents and petitions, to point to the existence of lead-glass at this time. The use of barilla, I may add, is incompatible with the preparation of a lead-glass; in such a glass it is essential that the alkali should be potash. On the whole, during the long period of the Mansell monopoly (from 1615 to, say, 1655) little progress appears to have been made in the manufacture of glass, but of course we must make allowance for the times of civil strife that filled the latter part of this period.