: J 



WATER. 



WATER-COLOUR PAINTING. 



in a recent communication ' On the Dittribution of Aqueou* \ 

 in the I'pl" 11 " Parts o( the Atmosphere,' have questioned both th.- 

 truth >( lialton'a hypothesis and the correctness of the appli 

 A mathematical argument, showing the incompatibility of tlu> h\|<-> 

 thesis of a separate vapour atmosphere with the fact*, will be fouml in 

 a paper by the late astronomer Beasel, translated in Taylor's 

 Scientific Memoirs,' vol. ii. A more generally appreciable form has 

 been given to this l>y I rac-hey, who aho has compared the 



result* calculated from Dalton'a hypothesis with the facta of the dis- 

 tribution of vapour in the atmosphere, as observed by Dr. Joseph I). 

 Hooker, the late Mr. Welsh, Colonel Sykes, and himself. From the 

 entire investigation he concludes that " The subtraction of the observed 

 tension of vapour from the total barometrical pressure, in the hope of 

 obtaining the simple gaseous pressure, must consequently be denounced 

 as an absurdity ; and the barometrical pressure, thus corrected, as it is 

 called, has no true meaning whatever." ( Proc. of Royal Soc.' vol. XL, 

 pp. 182-189.) 



On the other hand, the application of Dove's method for obtaining 

 the gaseous pressure, deduced from Dalton's hypothesis, in Major- 

 Oeneral Sabine's paper on the ' Meteorology of Bombay,' published in 

 the ' Report of the British Association ' for 1844, appears to have bee* 

 successful in bringing out true results, which also verify the law 

 assumed. It would appear that there is something important on the 

 subject yet to be explained ; probably in respect of the relation of the 

 observed phenomena which Dalton ' expressed by the hypothesis of 

 gaseous substances being vacua to each other, to their aggregate 

 pressure when mingled, and the manner in which that is made up of 

 their separate pressures, if such they have. 



WATER (Medical UK* of). Several of the uses of water having 

 been already stated, either under the article BATHIXG, or that of 

 FOOD in ABTS AND SCIENCES, or WATER, in NAT. HIST. Div., it is 

 intended to treat here of some of the applications of water. 



Slum-Water has been accused of causing goitre; but this charge 

 seems unfounded ; and the occurrence of that complaint is due to the 

 calcareous salts which the snow-water in its descent from the mountains 

 dissolves in large quantities. 



Such is the great purity of some springs, that they hare been 

 reckoned mineral waters, and resorted to as such. The chief of these 

 is Mai vein, the specific gravity of which is only 1'0002, and which con- 

 tains a smaller proportion of foreign ingredients than any other water. 

 The water now supplied to the City of Glasgow, from Loch Katrine, 

 is nearly equally pure, a point of great importance to the health of the 

 inhabitants, and to the numerous manufactories of that city. Water 

 artificially purified by Dr. Clark's process, is supplied to Woolwich. 

 Some of the springs of Matlock are likewise very pure. Those of them 

 which are thermal have their powers increased by the higher tempera- 

 ture ; but their beneficial effects, like those of Malvern, and Holywell 

 in Flintshire, are mainly owing to their extreme purity ; which shows 

 how conducive to health pure water is, compared with that which is 

 impure or contaminated. Many springs have their waters largely 

 impregnated with carbonic acid gas. These are sparkling and pleasant 

 to the taste, and when fresh-drawn produce some slight exhilaration. 



Water charged with much free carbonic acid should never be con- 

 veyed through leaden pipes, but through those of zinc or block-tin. 



tt'ell-tcater is generally obtained from a greater depth than spring- 

 water. It is also generally hard, or is apt to become so if kept in a 

 reservoir lined with bricks, unless they be coated with an insoluble 

 cement. The water from old wells is more pure than from recent ones, 

 the soluble particles having been all gradually washed away. The pump 

 and well waters in and about London, and chalky districts in general, are 

 mostly hard. (I'r.mt, ' On Stomach and Renal Diseases,' p. 210, 4th 

 edit) Not so that of the 'artesian wells, which is of unusual softness. 

 This renders water from these wells proper as a beverage for persons 

 with a tendency to certain forms of calculous complaints, to whom 

 hard waters are most hurtful. The causes of hardness in water and of 

 the injurious influence of it on the health of many persons, is scarcely 

 sufficiently understood. Kilt ration only removes mechanical impurities, 

 and even long boiling only precipitates certain of them, while in some 

 instances it renders the water harder. 1'or the analysis of water and 

 an estimate of it/-, mechanical impurities, see WATEH (Chtmiary) ; and 

 for the means of determining its hardness, see SoAP-TKST. 



DiililUd Water. For many chemical, pharmaceutical, and even .! 

 tetical purposes, water must be of greater purity than it is generally 

 found. For this end it is directed to be distilled, in which process 

 never more than two-thirds of the water put into the still should be 

 allowed to pass over. 



Toatt- Water. This is water boiled and poured on toasted bread, 

 which in some degree lessens the vapid taste. An agreeable and bene- 

 ficial degree of sapidity may be communicated to water which has been 

 long boiled, by adding, previous to drinking it, a little of the common 

 soda-water, which Is merely carbonic acid gas diffused through the 

 water under strong pressure. 



Mineral Wattn are generally characterised by possessing tome 

 principle different from what is found in common water, or some ol 

 the ordinary principles in unusual proportion, yet among these are 

 reckoned certain springs which have no claim to repute beyond what 

 is due to their extreme purity, such as Malvern and Holywell ; or to 

 having a higher temperature throughout the fear, than the mean ol 



.he latitude where they are situated. These last are clamed among 

 the thermal spring*, which are properly divided into two sections, tho 

 minrralital hot springs and the tmutmtratitttl, among which are some 

 only tepiil, such as Matlock, where some springs are 66", the lowest of 

 Jie class in Britain, and others cold, presenting this peculiarity 

 ihe tepid springs arise from fifteen to thirty yards above thu 1< . 

 ihe river Derwent, whilst those which arise either above or below 

 this range are cold. 



For practical purposes mineral-waters may be classed under four 

 iieads, each susceptible of secondary heads, according as they are hot 

 or cold, or have other peculiarities, namely ; saline, alkaline, chalybeate, 

 and sulphureous. It will not be possible to mention more than a few 

 of the most important of each. 



Saline aperient springs : of these some are hot, others coll. The 

 chief are Carlsbad, Marienbad, Kra, Kismngen, \Vieslra<! 

 Baden, Seidlitz, and Saidschutz, with 1'ullna, in Germany ; Cheltenham. 

 Leamington, and Harrowgate in England ; Dunblane, Pitcaithly, and 

 others in Scotland. 



Alkaline waters, owing their properties to different saline prin 

 are found at Carlsbad, Marienbad, KUsingen, 1'ullna, Saidnchut/. 

 Toplitz, and Wiesbaden, in Germany ; Vichy and Montd'Or, in France; 

 Harrowgate, Scarborough, and other Yorkshire springs, Cheltenham, 

 Leamington, Bath, and elsewhere, in England. 



Chalybeate waters : with these acidulous waters are often reel- 

 as the iron is often associated with much free carbonic acid gas. Some 

 of the chief are Spa, Pyrmont, Schwalbach, Marienbad, Aix-la-Chapelle, 

 and Seltzer in Germany; Tonbridge, Harrowgate, and Brighton, in 

 England ; and Peterhead, in Scotland. 



Sulphureous waters: Aix-la-Chapelle, Bareges, and other IV 

 springs, are hot ; Harrowgate, Askern, and others in York 

 Moflat and Strathpeffer, in Scotland, are also cold. 



loduretted and other waters. Many springs have of late been found 

 to contain a notable quantity of iodine or bromine, others contain both : 

 Cri'u/.nach, in Germany, contains both, but most iodine ; Llandrimld 

 and Park Wells (near liuilth), in Radnorshire, the springs issuing from 

 the lias at Leamington, Gloucester, Tewkesbury, and Cheltenham, 

 contain iodine; bromine, but not iodine, exists in small quantity, in 

 the saline aperient waters near London, such as Epsom, also in the 

 springs from the coal-formation of Ashby-de la-Zouch, Newcastle-oil- 

 Tyne, and Kingswood, and Bonnington near Edinburgh : Woodhall, near 

 Ashby-de-la-Zouch, contains most iodine of any British springs yet 

 investigated. 



Organic matters, termed Baregine, glairine, soogene, &c., have 

 found in many springs. Of these an account may be found in Dr. 

 Lankester's ' Askern, and its Mineral Springs,' p. 103. 



The waters of Setters (commonly called Seltzer) is exported to the 

 amount of above a million and a half bottles. So also those of many 

 other mineral springs ; but they all experience some deterioration by 

 time. To lessen this, artificial imitations are made [AKIIATI.D W A i 

 These are often very valuable, but always inferior in efficacy to the 

 waters drank at the springs. They are without the Jurantia, the 

 change of air, scene, relaxation from business, and more regular hours 

 and appropriate diet, insisted on at the chief watering places ; to say 

 nothing of the external use of many of the waters as baths, when 

 resort is had to the fountain head. 



(See Osann, DartteUung der bckanntcn HeUlyuttt* Knropai ; Qairdner, 

 On Mineral and Thermal Spring! ; Vatter, Tlteoreti*ch-praklitchtt Jtaml- 

 buch der HeilqueUenlehrc ; J}ictionaire del Eanx MintraUt, par MM. 

 Durand- Fardel, Le Bret, Lefort, et Francois; Paris, 1860. Report of 

 Commitrion on Health of Towni.) 



WATER-COLOUR PAINTING (in Italian, Acquarella ; French, 

 Aquarelle ; German, Wooer- t'arben). Among the ancients the colours 

 used in painting were usually rendered fluid by means of water ; the 

 names given to the different kinds of painting being derived from the 

 vehicle or medium mixed with the water in order to bind the colours. 

 TEMPERA, or distemper, in which glue or some other gelatinous biiuli-r 

 is employed ; Fuicsro, in which the colours are laid on a moist ground 

 of gesso, or plaster-of-Paris ; MINIATCUK, are all water-colour painting : 

 their history, and an account of the several processes, will be found 

 under their respective titles: see also the general article l'.\, 

 In ENCADSTIC PAJNTIXO, as the name implies, heat was employed, the 

 binding material being wax, or wax and resin ; but some even of the 

 methods of encaustic, or at least of wax-painting, as practised by the 

 ancients, were really water-colour, the war or resin being rendered 

 miscible by the addition of an alkali (nitrate of soda, or nitrate of 

 potash). Oil-painting was not practised, or only practised in an imper- 

 fect form, before the 15th century, when Van Kyck introduced the 

 use of oil and varnish, or a vehicle composed by boiling linseed, poppy, 

 ami nut oils with certain resinous mixtures. This vehicle wax. how- 

 ever, found to be so much better adapted than any then in use for 

 working, 'and so much more effective and durable, as to be generally 

 adopted by artists as soon as it became known ; and the various iu> 

 of water-colour painting were neglected, and fell into disuse, except for 

 mural paintings, for which fresco was still employed, and theatrical 

 paintings and miniatures, which were commonly painted in tempera. 

 [I'AINTINO; VAN Even, in Bioo. Div.] 



Water-colour painting, as the term is now understood that is, 

 painting on paper with colours diluted with water is a process of 



