Quincy's Lexicon medicum. A new medical dictionary : containing an explanation of the terms in anatomy, physiology ... and the various branches of natural philosophy connected with medicine / selected, arranged, and compiled, from the best authors by Robert Hooper.
- Date:
- 1811
Licence: Public Domain Mark
Credit: Quincy's Lexicon medicum. A new medical dictionary : containing an explanation of the terms in anatomy, physiology ... and the various branches of natural philosophy connected with medicine / selected, arranged, and compiled, from the best authors by Robert Hooper. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![S69 WA” reign contents of rain water appear to vary according to the state ©f the air throu r!i which it falls. The heterogenous atmos- phere of a smoky town will give some im- pregnation to rain as it passes through, and this, though it may not he at once percep- tible or. chemical examination, wall yet render it liable to .spontaneous change ; an;! hence, rain w .ter, if long kept, espe- cially in hot climates, acquires a strong smell, becomes full of amyia'euia, and in some degree putrid. According to Mar- graiff, the constant foreign contents of rain water appear to be some traces of the muriatic and nitric acid-; but as this water is always very soft, it is admirably adapted for dissolving soap, or for. the solution of alimentary or colouring matter, and ii is accordingly used largely for these purposes. The specific gravity of rain water is so nearly the same as that of distilled water, that it requires the most delicate instru- ments to ascertain the difference.' Rain, that fulls in towns, acquires a small quan- tity of sulphat of lime and calcareous matter from the mortar and plaister of the houses. 3. Ice and snow water. This equals rain water in purity, and, when fresh melted, contains no air, which is expelled during freezing. In cold climates and in high latitudes, thawed snow forms the constant drink of the inhabitants during winder; mid the vast masses of ice which float on the polar seas afford an abundant supply to the mariner. It is well known, that ip a weak brine, exposed to a moder-ite freez- ing cold, it is only the watery part that congeals, leaving the unfrozen liquor pro- portionabiy stron rer of the salt. The same happens with a dilute solution of vegetable aculs, with fermented liquors, and the like ; and advantage is taken of this pro- perty to reduce the saline part to a more concentrated form. Snow water has long- lain under the imputation of occasioning those strumous swel'ings in the neck which deform the inhabitants of many -of the Alpine valleys ; but this opinion is not sup- ported by any well-authenticated indisput- able’ facts, and is rendered still more im- probable, if not entirely overturned, by the frequency of the disease in Sumatra, where ice and snow are never seen, and its being quite unknown in Chili and in Thibet, though the rivers of these coun- tries are chiefly supplied by the melting of the snow, with which the mountains are covered. 4. Sipring water. Under this compre- hensive c*ass are included all waters that spring from some depth beneath the sod, and are used at the fountain head, or at least before they have run any considerable distance exposed to the air. It is obvious that spring water will be as various mi's con- tents as the substances that compose the 'EE. soil through which it flows. When the ingre- dients are not such as to give any peculiar medical or sensible properties, and the water is used for common purposes, it is distinguished as a hard or soft spring, sweet or brackish, clear or turbid, and the like. Ordinary springs insensibly pass info mi- neral springs, as their foreign contents1 become more notable and uncommon ; though sometimes waters have acquired great medical reputation from mere pu- ri v. By far the greater number of springs are cold ; but as they take the r origin at some depth from the surface, and below the in- fluence of the external atmosphere, their tempera!tire is, in general, pretiy uniform darm g every vicissitude of season, and always several degrees higher than the freezing point. Others, ag dn, arise con- stantly hot, or with a temperature a’ways exceeding the summer heat ; and the warmth possessed by the water is entirely independent of that of the atmosphere, and vines little winter or summer. One. of the principal inconvenwncies in almost erery spring witer, is its baldness, owing to the pr s nee of earthy salt*, which, in by far the greater number of cases, are only the insipid substances, chalk and selenite, which do not impair the taste of the water; whilst the air which it contains, and its grateful coolness, render it a most agreeable, and generally a perfectly innocent, drink ; though some- times, in weak stomachs, it is apt to occa- sion an uneasy sense of weight in that or- gan followed by a degree of dyspepsia. The quantify of earthy salts varies consi- derably ] but, in general, it appears that the proportion of five grains of these in the pint will constitute a hard water, unfit for washing with soap, and for many other purposes of household use or manufac- tures. The water of deep wells is always, ceteris paribus, much harder than tin t of springs which overflow their channel ; for much agitation and exposure to air produce a gradual deposition of the calcareous eartii * and hence spring water often in- ciusts to a considerable thickness the in- side of any kind of tube through which it flows, as it arises from the earth. The specific gravity of these waters is also, in general, greater than that of any other kind of water, that of the sea excepted. Springs that overflow their channel, and form to themselves a limited bed, pass in? sensibly into the slate of stream, or river water/ and become thereby altered in some of their chemical properties. 5. Hirer water. This is in general much softer and more free from earthy salts than the last, but contains less air of any kind; for, by the agitation of a long current, and in most cases a great increase of tempera- ture, it loses common air and carbonic](https://iiif.wellcomecollection.org/image/b21967222_0876.jp2/full/800%2C/0/default.jpg)
