328 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[August, 



Beat, on the banks of the Garonne is the best marble used in French 

 sculpture, but it is objected to as being of a dirty white, particularly 

 subject to deterioration on exposure to the external air, and it can 

 only be used, therefore, for decorations in rooms.' 



The principal deposits of marble now wrought are those of the 

 High and Low Pyrenees, the High Garonne, the Arriege, the Aude, 

 the Herault, the Vosges, and Straits of Calais. M. Geruzet, of Bag- 

 ncres de Bigorre (High Pyrenees), sent the most beautiful and varied 

 marbles this year. The marbles of Aspan, the stalactite marbles, and 

 the campanamarante marbles were those most admired. M. Geruzet 

 has set np on the Adour a marble work, which has 150 ?aws constantly 

 at work, besides 10 rough saws for cutting out the blocks, 7 lathes, 1 

 circular saw, a straight moulding frame, 4 machines for making fiat 

 slabs, and 1 machine which makes twelve rosettes at the same time. 

 M. Geruzet has obtained all the prizes usually awarded and the Legion 

 of Honour. M. Fraisse, of Perpignan, exhibited various tnaibles, in- 

 cluding white marble very near statuary, and white saccharoid mar- 

 bles, inlaid with sky blue, veined, yellow, grey, dark brown, and breccia 

 of all colours. A saw mill, moved by water, has been set up by him. 

 M. Philippot, of Perpignan, had works in breccia and dark cherry 

 (Griotte) marble of beautiful colour. Messrs. Tarride and Layerle- 

 Capel of Toulouse sent grand antique marble, and Messrs. Belhomme 

 and Ducos of Toulouse statuary marble. Among the marbles of M. 

 Fournier de St. Amand of Villeneuve-sur-Lot were a table and vase in 

 white marble, and a chimney piece of dark cherry marble, and another 

 in lumacelle marble, all worked by tlie convicts in the county jail. M. 

 Elie Corbier of Anduze (Gard) had some black marbles, as had M. 

 Bernard of Grenoble, and M. Pi'rroncel of Mure (Istre). M. Henry of 

 Laval (Mayenne) had black and veined marbles. This proprietor has, 

 on the Mayenne, a factory where -230 blades are at work. Messrs. 

 Landeau, Noycrs & Co. of Sablu (Sarthe) had compact black and 

 veined marbles, wrought by new machinery of their own invention. 

 M. Sappey of Vizille, Isere, sent some white marble tables, and M. 

 Lemesle rough blocks of alabaster. The quantity of marble imported 

 into France is 6,01)0 tons, valued at £20,000, and coining principally 

 from Tuscany being white statuary marble, and from Belgium being a 

 raadreporic grey and white marble, known as St. Anne marble, and 

 used for furniture, slabs in cottee houses, &c. The value of French 

 marble exported is £G,000. 



Lithographic Stones. — M. de Lasteyrie was the first to introduce 

 lithography into France from Bavaria, whence also the stone was first 

 exclusively obtained. The Societe d' Encouragement, influenced by 

 the increasing use of this article, offered a prize for the discovery of 

 lithographic stone in France, and in 1821 it was given for the quarry 

 found at Bellay in the Ain. In 1833 the supply being insufficient, the 

 Society ottered a fresh prize. Three years after several competitors 

 presented themselves for the quarries of Cliat-auroux, Tanlay (Yonne) 

 and the Ain. In 1837 the prize was awarded to the Chateauroux 

 stones, of which the supply was considerable, and the price 30 per 

 cent, below that of the Bavarian, and the quality much superior. 

 Stones from Solenhofen, near Pappenhe.ini, in Bavaria, are still import- 

 ed, being preferred as free from spots, cracks and other defects often 

 found in those of French origin. Two hundred tons of these stones 

 are imported annually. Messrs. Auguste and Paul Dupont of Cha- 

 teauroux, were at the head of the exhibitors this year. They have 

 set up a factory of 50 horse power. Several proprietors of the de- 

 partment of the Gard sent for the first time. 



Slates. — Anjou supplies some of the best roofing slate to the annual 

 value of £80,000, also Britaimy, the Ardennes, Correze, Lower Seine 

 and Dauphiny. Those of Angers are considered the best, because 

 they are very fine, verv hard, little acted on by the air, and are in thin 

 and light layers. The"RitDogne Slate Company (Ardennes) employs 

 a steam engine, three hydraulic machines, and 300 workmen, and pro- 

 duces annually 27 millions of slates. The slates are worked by M. 

 Moreau's machine. 



Millstones. — The best millstones are from the silicious beds around 

 La Ferte-sous-Juuarre in the Seine and Oise. Their reputation is so 

 great that the English and Americo-English send agents every year 

 to La Ferto to purchase. The adoption of the English mode of grind- 

 ing corn has much modified the exploitations of millstones. M. 

 Gueuvin, Bouchin and Co. are large manufacturers — they employ 

 between 400 and 500 men, and produce annually 700 millstones, and 

 about 100,000 pieces of stone for making millstones. Their stones 

 are wrought by machineiy. Naylies and Co. supply French millstones, 

 English millstones, and small millstones. Several machines for the 

 manufacture of millstones and their putting up were in the Exposition. 

 Here may be mentioned the manufacture of agate burnishers, po- 



1 For an explanation of mtrbles see the Dictionary of Marbles given in tliis Journal, 

 vol. ii. F, 4S2. 



lishcrs, &c., for the use of gilders, binders, &c. These articles were 

 formerly derived derived from Germany. 



Artificial millstones of silex and fl.it emery stones for cutlers, po- 

 lishers, &c., were exhibited by Messrs. Perrot and Malec, of Paris. 



A COMPENSATING PENDULUM. 

 At a meeting of the Societe Philomatique, M. Egger, Professor of 

 Greek Literature in the Faculty of Arts, communicated a method of 

 constructing compensating penduiuins, in which the two metals em- 

 ployed are connected by joints, and which have, in consequence, the 

 advantage of being entirely free from all want of homogeneousness, 

 arising from soldering. This method is founded upon the following 

 principle :— Let a, be the liypoteneuse of a right angled triangle, and 

 h, one of the sides adjacent to the right angle. If these two lines are 

 represented materially by metallic rods of different kinds, the third 

 side h, will retain a constant length, provided the lengths of a and h, 

 and their respective coefficients S, and 5', satisfy the following condi- 

 tions : — 



a" — 5' = a= (1 -)- 8) ' — 6- (1 + 8') •, 

 whence, in neglecting the very small fractions of the second order, 

 aJ 8 — 6- 8' = 0, or a : 6 : : /s/V^ : V^ 

 If, for example, the hypotenuse a, is of iron, and the side h, of 

 brass, we shall have 8' : 8 : ; 19 : 12, very nearly, whence 

 b : : Vly : Vl2 : : 5 : 4, very nearly. 



Thus we shall obtain a sufficiently perfect com- 

 pensation by a hypotenuse of iron^ 5, and one side 

 of brass = 4, whence it follows that the other side 

 will be represented by 3, which we will assume as 

 the height. 



Nothing is more easy to construct than this figure ; 

 it is the celebrated triangle with which Pythagoras 

 discovered the proposition of the square of the hy- 

 potenuse. 



To apply it, suppose we place together four tri- 

 angles, so as to form a lozenge, of which the sides 

 are iron, and := 5, while one diagonal of brass = 8 : 

 the second diagonal, (the matter of which is of no 

 importance,) will ^ G, whatever may be the tempe- 

 rature. Now letus imagine a series of these lozenges 

 arranged together firmly, one above the other in the 

 same vertical plane ; and to this effect, suppose iron 

 bars the length of each = 5, first united two by two, 

 in the form of a cross, and joined by their middles, 

 then let the different couples be united and joined 

 together by their ends, so that all the centres shall be 

 in the same vertical line ; and let the adjoining 

 couples be separated from each other by horizontal 

 brass bars each — 4. The total height of this 

 system will remain constant, and equal to 3, multiplied by the num- 

 ber of lozenges : this height will be the length of the pendulum.— 

 L'Imlitid. 



An Analysis of Gothic Architecture. By Raphael and J. Arthur 

 Brandon, Architects. London: Richardson. Parts 1 and 2. 

 The object of the Messrs. Brandon in this attempt is to present a 

 really practical work to the profession, composed of examples of good 

 authority, illustrated by original designs from actual measurements. 

 It is intended at the same time to be comprehensive and cheap, and 

 will include about 120 plates, which from what we have already seen, 

 will contain upwards of six hundred subjects and details. It is to 

 comprise windows, doorways, porches, buttresses, pinnacles, parapets, 

 gables, piers, arches, capitals, bases and church furniture. In every 

 case the details are amply and copiously given, the centres of the 

 tracery, and a scale. We observe that in the numbers before us, 

 which include many examples in thi> Norman, decorated and perpen- 

 dicular styles, th;it instead of being confined to cathedrals and colle- 

 giate churches, advantage has been taken of the parish churches in the 

 country, often little known and perhaps not generally accessible, but 

 which frequently afford valuable lessons. Thus in the ten plates, we 

 find the names of the churches of Orpington, Sutton at Hone, and 

 Northfleet, in Kent, Chesham Bois, and Chenies, Bucks, St. Alban's 

 Abbey, St. Michael's, Herts; Wallham Abbey, Essex; Basingstoke 

 and King's Worthy and Natelev, Hampshire. In each case we find 

 plans and ample sections of the mouldings, and generally every in- 

 formation which can be useful or acceptable to the practical architect 

 or enlightened amateur. 



