[721] [The solvent action of water upon lead is highly interesting on account of the very general use of leaden pipes and cisterns lined with this metal. From the researches of Lieut.-Col. Yorke, published in the Philosophical Magazine for August 1834 and January 1846, it would appear that a bright leaden vessel containing pure water, such as distilled water, and _exposed to the air_, soon becomes oxidized and corroded; oxide of lead being readily detected _in solution_ by means of sulphuretted hydrogen and other sensitive tests; but river and spring water exert a much less or no such solvent power, the carbonates and sulphates in such water preventing it. It is on this account that leaden vessels are used with such impunity, the crust which forms upon the metal entirely preventing all further action. However, as this crust consists partially of carbonate of lead, which is a very dangerous poison, great care should be taken on cleaning or scraping such cisterns to avoid using the water in which particles of the salt may have become diffused. Leaden cisterns are sometimes rendered unsafe in consequence of iron or zinc pipes being soldered or let into them, thus giving rise to galvanic action, which greatly facilitates the solution of the lead.] [722] Plin. lib. xiv. cap. 20. The same author relates a great many arts practised in regard to wine. [723] Plin. lib. xiv. cap. 19. That this method was practised in Italy is confirmed by Columella, lib. xii. cap. 20, and Didymus in Geopon. lib. vi. cap. 18. It is mentioned also by Dioscorides and Theophrastus. [724] Plin. lib. xxiii. cap. 1. [725] Ibid. lib. xxxvi. cap. 24. [726] “The wine of the island of Zante is almost as strong as brandy. It is supposed that this proceeds from the unslaked lime which is usually mixed with it, under the pretence that it then keeps better, and is fitter to be transported by sea.”--D’Arvieux, Voyages. [727] Christophori a Vega de Arte Medendi, lib. ii. cap. 2. [728] “No one sells wine at Tunis but the slaves, and this wine is not under the jurisdiction of the Tunisian government. They put lime in it, which renders it very intoxicating.”--Thevenot’s Voyages. [729] In Anleitung zur Verbesserung der Weine in Teutschland, Franck. and Leipsic, 1775, 8vo, the moderate use of lime is recommended. In France crude potash is put into wine instead of lime. [Acidity in wine was formerly corrected in this country by the addition of quick-lime. This furnishes a clue to Falstaff’s observation that there was “lime in the sack,” which was a hit at the landlord, as much as to say his wine was worth little, having its acidity thus disguised. Carbonate of soda is now most frequently used for the purpose.]