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.
873/888 (page 861)
![acids, and, with this last, much of the lime which it held in solution. The specific gravity thereby becomes less, the taste not solid:si;, but less freffi and agreeable, and out of a hard spring is often made a stream of sufficient purity for most of the pur- poses where a soft water is required. Some streams, however, that arise from a clean siliceous rock, and flow in a sandy or stony bed, are from the outset remark- ably pure. Such are the mountain lakes and rivule s in the rocky districts of Wales, the source of the beautiful waters of the Dee, and numberless other rivers that flow through the hollow of every valley. Switzerland has long been celebrated for the purity and excellence cf its waters, which pour in copious streams from the mountains ; and give rise to some of the finest rivers in Europe. An excellent ob- server and naturalist, the illustrious Haller, thus speaks of the Swiss waters, “ vulga- ribtis aquis Helvetia super onines fere Europe regiones excellit. Nusquam li- qiiiuas iljas aquas &c crystal!] simillimas se mihi obtulisse memini ppstquam ex Hel- vetia excessi. Ex scopulis ehiui nostrae per puros silices percolate rmlla terra vi- tiantur.” Some of them never freeze in the severest winter, the cause of which is probably, as Haller conjectures, that they spring at once out of a subterraneous re- servoir so deep as to be out of the reach of frost, and during their short course when exposed to day they have not time to ba cooled down from 53°, their original tem- perature, to below the freezing point. Some river waters, however, that do not take their rise from a rocky soil, and are indeed at first considerably charged with foreign matter, during a long course, even over a rich cultivated plain, become remarkably pure as to saline contents, but often fouled with mud, and vegetable or animal exuviae, which are rather suspended than held in true solution. Such is that of the Thames, which, taken up at London at low water, is a very soft and good water, and, after rest and filtration, it holds but a very small portion of any thing that could prove noxious or impede any manufacture. It is also excellently fitted for sea store ; but it here undergoes a remarkable spon- taneous change. No water carried to sea becomes putrid sooner than that of the Thames. When a cask is opened after being kept a month or two, a quantity of in- flammable air escapes, and the water is so black and offensive as scarcely to be borne. Upon racking it off, however, into large earthen vessels (oil jars are commonly used for the purpose), and exposing it to the air, it gradually deposits a quantity of black slimy nmd, becomes dear as chrys- tal, and remarkably sweet and palatable. The Seine has as high a reputation in France, and appears from accurate experi- ments to be a river of great purity. It might be expected that a liver which has passed by a large town, and received all its impurities, and been used by numerous dyers, tanners, hatters, and the like, that crowd to its banks for the convenience of plenty of water, should thereby acquire such a foulness as to be very perceptible to chemical examination for a considerable- distance below the town ; but it appears, from the most accurate examination, that where the stream is at all considerable, these kinds of impurity have but little in- fluence in permanently altering the quality of the water, especially as they are for the most part only suspended and not truly dissolved ; and, therefore, nit re rest, and' especially filtration, will restore the water to its original purity. Probably, .there- fore, t.l# most accurate chemist would find it difficult to distinguish water taken up at London, from that procured at Hampton Court, after, each has been purified by simple filtration. 6. Stagnated waters. The waters that present the greatest impurities to the senses, are those of stagnant pools, and low marshy countries. They are filled with the remains of animal and vegetable matter undergoing decomposition, and, during that process, becoming in part so- luble in water, thereby affording a rich nutriment to the succession of living plants and insects which is supplying the place of those that perish. From the want of suf- ficient agitation in these waters, vegetation goes on undisturbed, and the surface be- comes Covered with converva and other aquatic plants ; and as these standing wa- ters are in general shallow, they receive the full influence of the sun, which further promotes all the changes that are going on within them. The taste is generally vapid, and destitute of that tiesb'n'ess and agree- able coolness which distinguish spring wa- ter. However, it should he remarked, that stagnant waters are generally' soft, ami many of the impurities are only sus- pended, and therefore separable by filtra- tion ; and perhaps the mipafatableness of this drink lias caused it to be in worse cre- dit than it deserves, on the score of salu- brity, The decidedly noxious effects pro- duced by the air of marshes and stagnant pools, have been often supposed to extend to the internal use of these waters; and often, especially in hot climates, a resi- dence near these places has been as much condemned on one account as on the other, and, in like maimer, an improve- ment in health has bee.; as much attributed to a change of water as of air. Wat.r-b ash. See Pyrosis. Water-cress. See Nasturtium aqmtii cum. Water-dock. See -Hydrohpathum. Water-flag| yellow. See Iria pulustri](https://iiif.wellcomecollection.org/image/b21967222_0877.jp2/full/800%2C/0/default.jpg)
