1849.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



241 



The bricks of Sarcelles are those most used, but they are 

 extremely brittle: they are about 8 inches long by 4 inches by 

 2 inches; the thousand weigh nearly 1 ton 14cwt. 



Some bricks are made of the clays which occur in the gypseous 

 formations immediately round Paris. They resemble those of 

 Montereau in quality, but differ a little in colour, being of a deeper 

 red, and they are rather thinner and narrower. The thousand 

 weighs 1 ton IScwt. 



The composition of the St. Ouen and Pantin clays is as fol- 

 lows: — 



St. Ouen. Fantin. 



Silex, per cent 0-510 O'.'iCS 



Alumina 01411 O-lC'5 



Magnesia V\M 072 



Oxidf of iron 0030 0057 



Water 0-1S2 2li0 



In the neighbourhood of Bonnieres, in the valley of the Seine, 

 a mass of clay occurred, from which the white bricks used on the 

 Paris and Rouen Railway were made. Generally, the bricks used 

 between Paris and Harfleur are, however, of a red colour, and 

 made of a ferruginous clay. At Harfleur and Havre they are 

 white, the clay being calcareous and impregnated with the marine 

 salts. The mode of burning usually employed is in kilns; but of 

 late, near Rouen, many brickmakers have begun to burn in clamps. 

 Their success hitherto has been very equivocal. 



Of late years wooden floors have become general in Paris, but 

 the houses of the poor, and all the oSices, passages, and kitchens 

 of the best lodgings, are still paved with tiles; and it may, per- 

 haps, be owing to this custom that Paris is so comparatively free 

 from fires. The tiles are of four sorts for flooring purposes — viz., 

 the large hexagon, of 6j inches over the angles; the bastard hexa- 

 gon, of 5^ inches over the angles; and the square tiles, 6j inches, 

 and 8^ths of a side: the thickness varies from xsths to -j-^ths. 

 The square tiles are used for the hearths, the hexagonal tiles for 

 flooring. The best are made at Montereau, but their price is so 

 high that the preference is generally given to the tiles made at 

 Massy, near Palaiseau. Almost all the brickmakers of the neigh- 

 bourhood of Paris, howe^'er, make tiles at the present day, both 

 for flooring and roofing purposes. 



Many of the houses of Paris and the neighbourhood are covered 

 with tiles, though the use of this material is rapidly going out of 

 fashion. The best are made at Montereau, as is the case with 

 flooring tiles. They are of two sizes; for it is to be observed that 

 there is only one shape in general use — the pantile. Le grand 

 moule is about 1 foot long by 9 inches wide and | inches thick; the 

 part left uncovered is about 4g inches. Le petit moule is about 

 from 5k to 7i wide, by from 10 inches to II inches long. The 

 ridge tiles are 1 ft. 3 in. long by 1 ft. 1 in. development. 



A very great number of glazed tiles and common pottery chim- 

 neys and stoves are used throughout France. The dearness of 

 combustibles renders the use of open fire-places too expensive for 

 the lower classes. Iron also is too dear to be employed for grates, 

 stoves, ranges, cheeks, and the thousand uses we make of it in 

 England. 



The clay of Forges of la Seine Inferieure is composed of — 



Forges. Vaiivies. 



Silex, per cent 0-650 0-640 



Alumina 0-240 2.50 



Oxide of iron tii-ie c-oeo 



Water 0110 O-.OO 



Waguesia ■ lr;.ce 



lOllO 0-900 



The clay of Forges is used for pots for glass-making, and similar 

 purposes; that of V'anvres for kitchen-tiles. 



The firebricks used in Paris are either made at Stourbridge, or 

 at Hayange, on the Belgian frontier; some few are made in Bur- 

 gundy, but they do not resist well. 



One of the most ingenious uses made of pottery was in the con- 

 struction of the floors of some houses in a street recently erected 

 in the centre of tlie grounds of the ancient liotel Rougemont. At 

 the time of the erection of these houses, there was a strike amongst 

 the carpenters. The contractor adopted this manner of executing 

 the floors simultaneously with the walls, — that being the invariable 

 mode of proceeding adopted in Paris. These floors, however, cost 

 more than those executed in the usual mftuner, and, consequently, 

 have not been imitated. They were executed about 1845. 



III. Limes and Cements. — All calcareous stones, when exposed 

 to a sufhcient heat, part with the carbonic acid gas which enters 

 into their combination; but the limes resulting from the calcina- 

 tion assume different appearances, according to the chemical com- 

 position of the stones. These appearances are four in number, — 

 at least of those sufficiently frequent in their recurrence to form 

 the basis of a commercial classification. They are: — Firstly, as 



regards the manner of taking up water, divided into fat or thin 

 limes. The fat limes are those which, in slacking, augment at 

 least one-fourth in volume; the thin limes are those that remain 

 constant in their bulk. Secondly, as regards their setting proper- 

 ties, limes are divided into the hydraulics and non-hydraulics. 

 The hydraulic limes are invariably thin, — but all thin limes are 

 not hydraulic. 



An examination of the elaborate discoveries and researches of 

 the French chemists and engineers into this still very little culti- 

 vated branch of the chemistry of building, would lead us into far 

 too long a discussion at present. Suffice it to say, that the prac- 

 tice of the best architects, and of all the engineers in France, is 

 to use hydraulic lime to the exclusion of others, unless almost in- 

 superable difficulties, owing to their price, occur. In so damp a 

 climate as our own, we should do well to imitate their example; 

 the more especially as we have at hand the means of procuring both 

 natural and artificial hydraulic limes in unlimited quantities. 



The fat limes used in Paris are made at Senlis, Melun, Essone, 

 Champigny, Marly, Sevres, &c. The natural hydraulics are made 

 at Senonclies, and of late years at Meudon; the artificial hydrau- 

 lics are made wherever chalk is found in the proximity of clay, as 

 at Marly, Mantes, and in the neighbourhood of Rouen. 



The Lower Seine, from the neighbourhood of Mantes at least, 

 runs through the chalk formation; the country, right and left, is 

 of the same geological character for a great distance. Natural 

 hydraulic limes do not occur until we reach Havre, and all the 

 local consumption is tlierefore supplied by the factories of artificial 

 hydraulic limes. The most important of these are at Rouen, 

 where they assume very great importance, from the chemical and 

 mechanical skill employed. The materials used are the chalk from 

 the Mount St. Catherine, and the argillaceous deposits of the 

 neighbourhood; the proportions of the different ingredients, and 

 the degree of burning, depending upon the rate of setting re- 

 quired. 



At Havre, upon the outcrop of the chalk, or rrtther at the junc- 

 tion of the chalk and theWealden formations, abed of argillaceous 

 limestone is met with, which yields a very superior hydraulic lime. 

 In the valley of Harfleur a large establishment has lately been 

 formed for the making of artificial hydraulics; and all the immense 

 dock or fortification works executed at Havre have been con- 

 structed with either one or the other. Cement is only used for 

 pointing, or, on extraordinary occasions, for rendering works ex- 

 posed to the action of the sea immediately after being finished. 



The cements used in Paris are principally made in Burgundy, at 

 Pouilly. They participate of the nature of our Roman cements; 

 but do not acquire so great a degree of hardness. The same ob- 

 jection is to be made to the Vassy cements; and to the artificial 

 cements made at Rouen with chalk and pounded bricks. The 

 French architects and engineers do not advocate the use of cement 

 to the same extent we do in England. Personally, I think they 

 are nearer the truth than we are. Materials which set so rapidly 

 may decay in the same manner. The processes of nature are 

 slow, at least where great duration is its object; and we ai-e most 

 likely to succeed by following the same course. The competition, 

 moreover, in the supply of cement is so great, that the article, as 

 usually sold, is little better than sand. Even the extreme rapidity 

 of the setting of cement is an objection to its use in many ordi- 

 nary cases, for it requires so much care in its manipulation as to 

 render it liable to be slighted where the interest, or even the care- 

 lessness of the workman, may oppose its receiving proper at- 

 tention. 



Occasionally, in the neighbourhood of the large towns, the houses 

 are entirely built with rubble-stone, or of bricks, and covered with 

 a coat of piaster. Cement is never used for this purpose, nor does 

 there appear to be any necessity for its introduction; the climate 

 of France is sufficiently dry, and the plaster, as usually employed, 

 is sufficiently capable of resisting the atmospheric changes, to ren- 

 der the use of the more expensive material unnecessary. Precau- 

 tions require, however, to be taken iu the application of plaster. 

 The tops of cornices, and ail weatherings, require to be covered 

 with zinc; the parts of the houses near the ground must be ren- 

 dered with a less hygrometric material; but for all other positions 

 plaster succeeds remarkably well. Internally, it is the only mate- 

 rial used in any part of France within reasonable distance of water- 

 carriage from the gypsum quarries. Stuccos and imitations of 

 marbles are sometimes employed in public buildings, but very 

 rarely in private houses. 



IV. M'^ooDs. — The practice of the French architects in the use 

 of wood differs little from our own. On the sea-board, and in the 

 large commercial towns, Swedish and Baltic fir is principally em- 

 ployed; in the interior oak is cheap enough to insure the prefer- 



32 



