126 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[April, 



in that state be subjected to strong pressure between stee! dies, the powder 

 is compressed into about a fourth of its bulk : it then undergoes a process 

 of serai-vitrification, and is converted into a compact solid substance, of 

 extraordinary hardness and density ; much less porous, and much harder than 

 the common porcelain, uncompressed. 



This curious, and as it has since proved, very important discovery, was first 

 applied to the manufacture of buttons, to supersede those of mother-of-pearl, 

 bone, &c. The buttons thus stamped out of porcelain powder are capable of 

 resisting any pressure to which they are subject in use, and are more durable, 

 as well as cheaper, than buttons of the materials ordinarily used. 



The applicability of this ingenious process to the manufacture of tessera; 

 for pavements soon afterwards occurred to Mr. Blashfield ; who made ar- 

 rangements with Messrs. Minton & Co. (the manufacturers appointed to work 

 Hr. Prosser's patent), for a supply of small cubes made according to the 

 new process; these he submitted to various trials and experiments, and 

 having found them in every respect suitable for the purpose, he has recently, 

 in conjunction with Messrs. Vyatt, Parker, & Co., carried out the invention 

 on an extensive scale. Tessera? of various colours and forms — red. blue, 

 yellow, white, black, brown ; quadrilateral, triangular, rhomboidal, hexagonal. 

 &c. — have been manufactured on this principle in large numbers ; pavements 

 of considerable extent have already been constructed with theni ; and they 

 have been found to possess the following advantages : — 



First, being formed in similar steel dies, they are of uniform size and shape, 

 so that they can be fitted together accurately in the laying down of the most 

 complicated designs. Secondly, being all composed of the same material, 

 variously coloured, tbey are all of precisely equal hardness, so that pavements 

 made with them are not liable to fall into hollows in use. Lastly, owing to 

 the effect of the intense pressure under which they are made, they are quite 

 impervious to moisture, of a flinty texture throughout, and, in a word, to all 

 intents and purposes absolutely imperishable. 



In these several respects, their superiority to the Roman tesserae, (which, 

 as we have seen, were shaped imperfectly by hand, and differed from each 

 other in hardness,) must be manifest to the reader. Nor less conspicuous is 

 the superiority of the modern process of uniting the tessera; to form pave- 

 ments. 



For this purpose (instead of spreading the cement on the surface to be 

 paved, and laboriously setting each single tessera in it, according to the 

 directions of Vitnivius), the pavement is first put together, face downward, 

 on a smooth surface, so that the tessera- find their level without any trouble 

 to the workman ; and as soon as a sufficient portion of the design is finished, 

 it is backed with fine Roman cement, which is worked in to fill the crevices 

 between the tessera; ; the pavement is thus formed into smooth flat slabs of 

 convenient size (according to Mr. Singer's method), and these are laid down 

 on a foundation properly prepared in the usual way. 



One peculiar feature of this process is, that private persons, if so inclined. 

 may set out their own pavements in the coloured tessera-, leaving it for a 

 ■workman afterwards to cement aud lay down the slabs. Fine mosaic work 

 for the tops of tables, for illuminated monuments, &c. may be made in the 

 same manner with a superior kind of tessera;, glazed on the surface, and 

 richly ornamented in gold and colours. 



Pavements thus constructed are singularly beautiful. The outline of the 

 design strikes clearly and sharply upon the eye, and the brilliant colours of 

 the tesserae are reflected from the level surface, uninterrupted by those broad 

 uneven lines of cement, which in the Roman pavements detract so much from 

 the general effect. The truth of every line and angle in the figure, aud the 

 just proportion of all its parts, however complicated and various, impress the 

 mind with an agreeable sense of order and precision. Such, indeed, is the 

 exactness and facility of the workmanship in these pavements, that the 

 oblique and intricate intersections of the Mauresque designs are as readilv 

 executed as the simple rectangular patterns of the Pompeiiau style. Even 

 the scrolls and twisted guilloches, the quaint emblematical devices, and gro- 

 tesque representations of horses, warriors, &c, found in the most elaborate 

 of the Roman pavements, may be accurately imitated with the new stamped 

 tessera;. 



The Roman designs, however, have little to recommend thera to the mo- 

 dem artist, beyond their historical interest. Even the earliest of them, 

 which are the best, were produced subsequently to the Roman invasion of 

 Greece, when art was everywhere declining; and they abound with indi- 

 cations of the extravagant and licentious taste which grew up amidst the 

 general corruption of Roman manners, occasioned by the rapid influx of 

 foreign wealth and foreign habits of luxurious excess. 



When designs after the antique are required, the elements of them should 



rather be sought in the beautiful decorations of the Etruscan vases, and in 

 the admirable remains of Greek art in general, during its best period — i. e. 

 from about 400 to 200 B.C. or during the time of Phidias, Praxiteles, and 

 their immediate successors. (Such are the mode's which have guided the 

 composition of the magnificent tessellated pavement designed by Mr. Barry, 

 and executed under his direction by Mr. Singer, for the hall of the New 

 Reform Club ; a pavement so beautiful and so generally admired, that it can 

 hardly fail to give an impulse to the re-introduction of mosaic decoration, 

 hitherto so sparingly employed by modern architects.) 



For Mauresque designs, the mosaic dados of the Alhambra may be advan- 

 tageously consulted. They are executed in glazed earthen tiles, variously 

 coloured, shaped with considerable exactness, and joined with cement. They 

 present many examples of ingenious arrangement and well-contrasted 

 colouring. 



But, whichever of these various styles the architect may adopt, he will 

 find that, for the realisation of his conceptions, there is no material which 

 presents so many advantages as the compressed porcelain tessera; — whether 

 on account of their uniform size and shape — the purity and brilliancy of 

 their colours — or their extreme hardness, and unalterable durability. 



NEW CHURCHES. 



At the request of several architects residing in the country, we give the 

 following Suggei o u / notions, as amended May, 1842," of the 

 '• Incorporated Society fur Promoting the Enlargement, Building, and 

 Repairing of Churches and Chapels."] 



1 Site. — Central, with regard to the population to be provided fur ; dry ; 

 if possible, rather elevated, but not on a high or steep hill ; — not near nui- 

 sances, such as steam-engines, shafts uf mines, noisy trades, or offensive 

 manufactories', — accessible by foot and carriage-ways, but not so ne;ir to 

 principal thoroughfares, as to subject the service of the church to the danger 

 of being incommoded by noise. The building to stand east and west as 

 nearly as possible. 



2. Style and Fmn, — No style seems more generally suitable for an English 

 church than the Gothic of our own country, as developed in its successive 

 periods. The Norman (or Romanesque) style is also suitable, and offers 

 peculiar advantages under certain circumstances, especially v. hen the material 

 is brick. The Society earnestly recommend that, in the proportions and 

 great features, as veil as m the details, good ancient examples should be 

 closely followed. 



For Gothic churches, the best form is cither the cross, consisting of a nave, 

 transepts, and chancel, or the double rectangle, composed of a nave, with or 

 without side aisles, and of a chancel. In a chapel, the single rectangle is 

 also suitable ; the length being at least twice as great as the breadth. If the 

 funds do not suffice to complete satisfactorily a design, otherwise eligible, or 

 if the circumstances of the neighbourhood render it probable that, at no 

 listance of time, the building may be enlarged ; it is better to le i,ve a 

 part of the original design, as. for example, side aisles or transepts, to a fu- 

 ture period, than to attempt the completion of the whole design at once in an 

 inferior manner. In such a case, the temporary walls and fillings up of 

 arches should be so built, as clearly to show that they are temporary, and 

 that the building is incomplete, but at the same time not without due regard 

 to ecclesiastical propriety, 



3. Foundation. — To be surrounded, if requisite, by good covered drains. If 

 the soil wants firmness, the walls may often be better secured from partial 

 settlements by spreading the footing on each side, than by deepening the 

 four; lati n, or resorting to more expensive works. 



In all irregular or doubtful suils, concrete is recommended for the foun- 

 dations, in preference to any other material. 



No interment should be permitted under a church, except in arched vaults 

 properly constructed at the time of building the church, with entrances from 

 the outside only ; nor should any graves be made within 20 feet of the ex- 

 ternal wall. 



4. Area. — It would tend much to the preservation of churches, and render 

 them more dry. if a paved opened area, not less than 18 inches wide, were 

 made round them, and sunk 6 or 8 inches below the level of the ground about 

 the church, with a drain from the area to carry off the water. Or the same 

 objects might be attained either by turning a segmental arch from the wall 

 outside the footing, or by bedding in the wall a course of slate in cement. 



5. Basement. — The inequalities of the ground, the dampness of the soil, BsC 

 often render it desirable to have crypts under a church. Tbey should be of 

 a massive construction, turned upon semicircular or segmental arches, re- 

 sembling the early examples, entered only from without. 



