The peculiar gas to which this destructive quality is owing, is generally _Sulphuretted Hydrogen_, sometimes existing in combination with Ammonia (_Hydro-Sulphuret of Ammonia_). _M. Dupuytren_ has also shewn that the _Plomb_ is sometimes occasioned by _Nitrogen gas_. _Hallé_ in his work entitled “_Recherches sur le Mephitisme des Fosses d’Aisances_” has proposed various methods for securing the _nightmen_ from the dreadful effects of this gas, as by _ventilation_ and _fumigation_. _M. Dupuytren_, however, has satisfactorily proved that Chlorine, by decomposing it, is its true antidote, by which _Hydro-Choloric_ acid (_Muriatic_,) is produced, and _Sulphur_ deposited. In some cases the Sulphuretted Hydrogen has accumulated to such an extent, that explosions have occurred in privies on the introduction of a light. We have heard that dreadful ones have happened in the _Fosses d’Aisances_ in the Rue St. Antoine, and in those of Gross Caillou, and Petit Bourbon; and very lately in that of the House of Correction at Clermont-oise, in which many lives were lost. A similar accident has happened in London; we copy the following paragraph from the _Morning Advertiser of Friday Feb. 5, 1819_.—“_Singular Explosion_,—A few evenings ago, at the Two Brewers Tavern, Redcross-street, Southwark, a person took a candle into the privy, and laid it upon the seat, the air confined underneath caught fire from the candle, and immediately exploded, the seat was forced up, and the person was burned considerably, but not dangerously.” Footnote 167: The writings of Portal, Gériel, Laborie, Parmentier, Alibert, Dupuytren, Cadet de Vaux, and Hallé, contain ample illustrations of this subject. The reader is also particularly directed to an Essay by Dr. Gerand, entitled “_Essai sur la suppression des Fosses d’Aisances. Paris, 1786_.” See also _Dictionnaire de Police_—Art. “_Latrine_.” Footnote 168: