Those glasses in which those spirits are kept are for the most part stopt with cork, or wax, upon which afterward bladders are bound: which stopping is convenient for some spirits, that do not prey upon cork or wax: For all corrosive spirits, as of vitriol, Allome, common salt, nitre, _&c._ corrode cork, and lixivial spirits, as that of harts-horn, tartar, salt armoniack, urin, wine, _&c._ melt wax, and penetrate it. And although other stopples might be made, which might retain both sorts of spirits, yet it would be tedious and laborious to open those so often, and to stop them again. Wherefore I have found out a fit kind of glasses, _viz._ of such, whose mouths have distinctions, and are fit to receive their covers; as it appears by the delineation. [_See the first figure_]. _A._ signifies the cover: _B._ the glass containing the spirit. _C._ a drawer by the help whereof the spirits are taken out of the glass, when there is occasion, into the distinction in the brim of the mouth; _viz._ of the glass that contains the spirit, is put quicksilver, and upon this is put a cover; this being done, the Mercury closeth the joynts of both glasses running in the brim, so that nothing at all can evaporate: for the spirits do not penetrate the Mercury, unless they be very corrosive (a thing to be noted) which then in process of time turn the Mercury into water, but very seldom; and then the Mercury is to be renewed. But we need not give so much honour to corrosive spirits, being not to be compared to those volatile ones, which being abstracted from corrosives not prey upon Mercury; and much less than these, do lixivial spirits corrode Mercury; and for the sake of these were these glasses invented, by the help whereof most subtile spirits are without any loss of their vertues, if you please, a very long time preserved and kept. And because when there is occasion the spirits cannot be poured forth by reason of the Mercury in the brim, you must get a drawer like to that, by the help whereof wine is taken out of the vessel, but lesser, having a belly with a little mouth made very accurately. This being let down you may take up as much as you please, as is needful; the upper orifice whereof being stopped with the finger nothing drops out; being put into a lesser glass is thence poured forth for your use. Then you must again cover the remainder of the spirit that is in the glass, and as oft as is needful take out with that drawer as much as is useful. And this is the best way by which the most subtile spirits are retained; which also are very well retained in those glasses, whose stoples are of glass smoothed with grinding. But this is a more costly way of keeping in spirits, and it is done after this manner. _How glass stopples are to be smoothed by grinding for the retaining of spirits in their glass vessels._