Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 1, 1802).djvu/47

23&#93; AIR We are happy to add, that this va- luable improvement has also been, adopted in this country. An apparatus invented by Mr. Salmon, of Caritei'bury, for the ex- pulsion of noxious air from wells, has been* employed with consider- able success. Air-balionns are constructed upon similar principles ; they continue to ascend, so long as the inflammable gas with which they are rilled be lighter than the atmosphere with which they are surrounded. Noxious and mephitic vapours, arising from wells and other sub-: terraneous places, may be effeel corrected by simple ventilation, or the admission of such portions of vital air as will render the whole sufficiently respirable. To ascertain whether the air of a mine, well, cellar, or large cask, be safe, a lighted candle, suspended by a cord, ought to be conveyed to the bottom, before any person ven- ture to approach it. Should a slight explosion take place, or the light burn dimly, or even be extinguished, the air is certainly noxious ; but if the flame continue bright, no danger is to be apprehended. Another easy expedient of puri- fying foul air may be adopted, by pouring several vessels of boiling water into such receptacles, before any person be suffered to descend. A still better method of dispel- ling the deleterious air from deep wells or pits, is the following: take a leather tube of sufficient length to reach to the bottom of the shaft or cellar ; fix the nozle of a pair of large bellows to die top, and work them briskly for a few minutes : thus fresh air will be introduced, the flame of the candle, on trial, W not be extinguished, and we may descend without any danger. AI R D Artisans who are employed oves charcoal- fire, such as dyers, gilders, refiners of metals, &c. are exposed to considerable danger from the vi- tiated state of the air : to avert the injury to which their lungs are thus exposed, it would be advisable to place near them a flat-bottomed vessel filled with lime-water, and to renew it every other day, or go often as a variegated film or pellicle appear floating on such water. This powerfully attracts and absorbs the pernicious exhalations produced from the burning of charcoal. Likewise, in the construction of chemical laboratories, smelting-r mills, and similar offices, proper attention ought to be paid to their free and constant ventilation ; as die metallic fumes, and other noxious vapours which they generate, are highly detrimental to health. In chronic diseases, especially those of the lungs, a change of air is strongly recommended. It has sometimes, independently of any other circumstance, proved highly beneficial ; inasmuch as patients have breathed more freely, even th( nigh removed to a damp and con- fined situation. The following places in the vici- nity of London, have been found in the spring season to be most conge- nial to consumptive persons, viz. Camberwell, Peckham, die lower parts of Clapham, the drier parts of Lambeth, Battersea, Fulham, Chel- sea, &c. As the more temperate season advances, the higher situa- tions, such as Paddington, Penton- villc, Hampstead, Highgate, &c. may then be resorted to with ad- vantage. Aha Cespitosa, L. See Turfy Hair Grass. AIR-BATH, in its general ac- ceptation, implies a contrivance for C 4 die