WATER-GLASS PAINTING. 



WATER-PIPES. 



744 



briefly tins, u he proved by experiment : a concvity U formed by 

 the falling water at the point where it strike* the water below ; this 

 close* in a* soon a* the least motion hai been imparted to the surface, 

 and the air within it is carried downwards. It will readily be aeen 

 how illustrative Uiii explanation is of a part of Capt. B. Hall i account 

 of the air- bubbles at the Niagara falls, and of the applications of it 

 above ; but no part of the air, it must be inferred f n>ra the experi- 

 ments of Professors Magnus and Tyudall, is carried down by adhesion 

 to the water. 



In another port of his paper, Professor Tyndall, illustrating experi- 

 mentally the subject of the contracted vein [HYDRODYNAMICS, col. 774], 

 describes the resolution of the vein or stream of water, after passing 

 the contracted section, into detached masses ; and observes, " Follow- 

 ing the jet downwards, we find that these mssset become more and 

 more attenuated ; and were the height sufficient, they would fin.-illy 

 appear as a kind of water -dust, an example of which on a large scale is 

 furnished by the Staub-back, near Lauterbrunnen, in Switzerland. 

 Traveller* usually attribute the breaking up of the Staub-bach to 

 atmospheric resistance, but the latter has comparatively little to do in 

 the matter ; were the surrounding space a vacuum, the same would be 

 exhibited." This indicates an additional and very effective cause of 

 the production of waterfall 'spray, and is probably applicable to the 

 phenomena of the Voring Fos, noticed above, which appear not to be 

 accurately understood. (See ' Phil. Mag.' Series 4, vol i. p. 1, and 

 p. 105.) 



WATER-GLASS PAINTING, a method of painting in which the 

 vehicle, or binder of the colours, is a soluble alkaline silicate. This 

 process, which has been in use for some years in Germany for mural- 

 painting, and in which Kaulbach, among others, has painted all his 

 later wall-pictures, appears to have been invented, or greatly improved, 

 by Dr. Johann N. Von Fuohs, who termed it Stcreochromy, ami pub- 

 lished a pamphlet explanatory of the process and pointing out its 

 advantages. This has been translated for private circulation by 

 direction of the Prince Consort (chiefly with a view to the consider- 

 ation of the applicability of the process to the paintings in the New 

 Palace at Westminster), under the title of 'The Manufacture, Pro- 

 perties, and Applications of Water-Glass (soluble alkaline silicate), 

 including a Process of Stereochromic Painting.' Mr. D. Macliso, RA., 

 who was engaged on the preparatory labours connected with painting 

 in fresco a large picture, ' The Meeting of Wellington and Blucher,' 

 in one of the two spaces (45 feet in length) in the Royal Gallery of the 

 House of Lords, and who had been greatly impressed with the failure, 

 ts regards permanency, of the recently -painted frescoes, was led by a 

 perusal of this pamphlet to determine on submitting the water-glass 

 process to a searching investigation. He accordingly made various 

 experiments, and, not succeeding to his satisfaction, proceeded to 

 Germany to make himself acquainted with the method as actually 

 practiced there, and to examine the works executed. The result was 

 his conviction of its suitability. He has since executed various trial 

 pictures, and he is now painting his great picture with water-glass. 

 Mr. J. R. Herbert, RA., who U engaged in painting the Peers' Robing- 

 Rooin, also, having, " after repeated experiments, modified it according 

 to his own views," expresses himself entirely satisfied with it. As its 

 working capabilities have so far satisfied the practical artist, and the 

 finished examples appear to have withstood successfully not only the 

 effect of time, as yet too brief to be conclusive, but also the various 

 tests hitherto applied, the process would seem to merit very attentive 

 consideration. The frescoes painted within the last few years, not 

 only in this country, but in Germany, where so much more attention 

 has been given to them and artists are so thoroughly familiar with all 

 the working details, have for the most become deteriorated to a very 

 marked extent ; and it will l<e an immense gain if the water-glass 

 process proves to be a really permanent, as it would seem to be in 

 other respects an efficient, substitute. It will be no doubt interesting 

 to give a brief general statement of the process ; for further particulars 

 we refer to the ' Twelfth Report of the Commissioners on the Fine 

 Arts' (1861), in an appendix to which Mr. Macliso has given a very 

 full account of bis experience and ample details of the modes of 

 working. 



The Water-Glass is composed of powdered quartz (silica) boiled in 

 purified potass or soda, but, according to Dr. Pettenkofer, the chief 

 authority on the subject, the potass solution is to be preferred. It is 

 prepared by chemists of different degrees of strength, according as it is 

 to be employed for laying-on the colours or for fixing. The pigments 

 are the same as those used in fresco-painting, but zinc-white is 'the 

 only white that can be relied on. The ground is an intonaco, formed 

 of river-sand and Portland cement, precisely as for FRESCO, but some- 

 what mi.re absorbent Kaulbach has the ground prepared with a 

 granulated surface, insisting that " it should feel to the touch like a 

 coarse rasp ; " but this does not appear to be necessary. A smooth 

 ground, if carefully prepared, takes the colours with equal facility ; 

 and, in fact, the degree of roughness or smoothness may be regulated 

 at the pleasure and according to the manner of the painter. After the 

 intnnaco has been well dried, and the cement hardened, the superficial 

 sand is to be swept off, and the surface to be moistened with a saturated 

 solution of carbonate of ammonia (Mr. Mac-lino, we believe, employs 

 liine-water). when it is ready for painting on. 

 The painting itself nay b* "scented in two ways. In the first, the 



water-glass in a diluted form is mixed with the colours, and used as a 

 vehicle in working. But Mr. Maclise found that it was hardly possible 

 to work with such a vehicle with sufficient facility, " because of its 

 stiffening the brush, and, as it were, petrifying the contents of the 

 palette before the painting could be accomplished even by the most 

 rapid execution." The solution may, of course, be diluted so as to 

 admit of the painting being executed with much greater facility ; I nt 

 this can only be done at the expense of the fixing qualities of the fluid. 



The other method that employed by Kaulbach and his assistants, 

 and adopted by Mr. Maclise consists in simply using distilled water 

 as the vehicle, and finishing the parts as they advance ; and on the 

 following day, when the finished work U quite dry, applying to it a 

 solution of water-glass, formed of " two parts water and one of the 

 concentrated liquor imported from Berlin, and this solution having 

 been twice applied, the painting is now perfectly fixed." (Maclise.) 

 Mr. Maclise applies the water-glass " freely with a large Sat water- 

 colour brush." The Berlin artists use a syringe of peculiar construc- 

 tion ; and Mr. MacUse finds great advantage in " shedding, by means 

 of a syringe, a spray of coloured water over any portion of the wall- 

 painting," and thus producing " very easy and pleasing changes in 

 hues" where it may bo deemed necessary. The principal conditions of 

 success appear to Mr. MacUse to be that the picture should be thinly 

 painted, water be freely used, and the ground be carefully pi 

 and very absorbent. 



In appearance water-glass painting bears a close affinity to fresco. 

 It is fiat, free from glossiness, and the colours appear opaque ; but the 

 surface may be rendered glossy by using a concentrated solution of the 

 water-glass as a varnish. As it is for mural painting, however, that the 

 water-glass method seems especially fitted, the flat unahining surface is 

 an advantage. In comparison with fresco, its superiority seems to con- 

 sist in the colours remaining quite unaltered whilst working and when 

 dry; in the process allowing the picture to be retouched and c 

 out to any degree of finish not only during its progress but after tin- 

 " fixing ; " and, finally, that it promises to be permanent. On this hut 

 and most important point we may remark that whilst Kaulbach's great 

 frescoes have become seriously deteriorated, his large water-glass 

 paintings remain quite uninjured ; and in Munich some stereochrotne 

 pictures are said to have existed for twenty years without exhibiting 

 any symptoms of decay, whilst the frescoes are alUmore or less 

 damaged. 



WATER, HOLY (in French, Eau Unite, or blessed water ; but in 

 Italian, Aqua santa, as in English), is water bleesed by the priest, 

 which is used in many ceremonies of the Roman Catholic church, as 

 in the offices of baptism and burial, and in various parts of the mass or 

 ordinary service. There is commonly a font of holy water in the porch 

 of Roman Catholic churches, into which the congregation as they enter 

 tlie church dip their fingers, and then make the sign of the cross upon 

 their foreheads. The holy water is mixed with salt ; and this is said 

 to have been first done by Pope Alexander I., in the beginning of the 

 2nd century. Some make Pope Alexander to have been the inventor 

 of holy water altogether. Protestant writers have been accustomed to 

 trace the holy water of the Romish church to the pontifical lusti 

 of the pagan Greeks and Romans ; but both the pagan and the 

 tian practice may perhaps be more correctly referred to the natural 

 feeling which points out water as the symbol of purification. In the 

 ancient churches, in the middle of the Atrium, or square plot of 

 ground between the porch and the church, was commonly a fountain 

 or cistern of water, in which the people washed their hands and faces 

 before they entered. Holy water is also used in the Greek church, 

 but without salt. The mixture of the salt and water U interpreted by 

 some Roman Catholic divines as typifying what is called the hypostatic 

 union of the nature of Christ, the salt being the emblem of his divinity, 

 the water of his humanity. 



WATER-MACHINES. [TrnniNES; WATER- WUEELS.] 



WATER-MEADOWS. [InniGATlON.1 



WATER-MILLS. [WATER- WHEELS.] 



WATER-PARTING, in physical geography and geology, the term 

 recently substituted for that of Watershed, taken as the equivalent of 

 the German WamcncliriJr, in its primary and original signification, tint 

 of the line of separation between the contiguous basins of two rivers. 

 [RlVEHS; WATKRshED.] 



WATER-PIPES. In addition to what has been said on the subject 

 of the flow of water in pipes under PIPE and WATER Srrri.v, it may 

 be desirable here to mention a few practical matters connected with 

 their manufacture and use. 



The wooden pipes formerly employed were made from elm trees, 

 and of about 14 or 15 feet in length, the diameter rarely exceeding 

 9 inches ; the interior was bored out by an auger ; the joints were of 

 the kind known as the spigot and faucit, in which one end of the tree 

 was tapered for a length of about 9 inches, and the end of the pipe 

 destined to receive that taper was rimertd nut to fit it. These pipes 

 have now been entirely abandoned, on account of their not being able 

 to resist the pressures they are exposed to in modern works, and of the 

 bad flavour they communicate to the water. 



The cast-iron pipes are laid with socket joints run with lead ; the 

 iliptlmf the joint being proportioned to the diameter of the pip<-*, 

 but even in the largest it does, not exceed 6 or 8 inches. A grr.it 

 effort has lately been made to introduce turned and bored joints for 



