Marbres en Minervois

The rock, the gesture and the tool

Saverio Salvinoni the career of Polvacio

The rock

To update then implemented of the marbles was done using processes and of techniques tested with the wire of the ages, unceasingly transmitted and improved. Borings of the mine splits up the matter, breadths glares of the peak which releases it., the sharp striations of the points which open it and equalize it: each stage of a slow change printed deep or light brands, those of the gesture which achieves, dimension hidden, forgotten but colossal and deeply human of work to come.

The marble is by layers and masses, which are sometimes very thick and very considerable; those which are closest to the surface of the ground are commonly the least good, being filled of slits, the cracks and what the monumental masons call of the terraces, or veins of a foreign matter, which stop it and prevent that one cannot work successfully.

Carriers sawing a block, on which is posed the sandy water bucket, detail of a drawing of Saverio Salvioni

The gesture

Boring of a mine, detail of a drawing of Saverio Salvioni. With the foreground, peak, points and bar with mine widened, to dig by strikings and successive rotations of broad combustion chambers

Size measures displacement

By the end which enters the rock and which must open there it is a little larger than by the medium: there was a small point very with this end, to four coins.

a man holds the splinter and turns gradually it, while two others strike with two large iron hammers to make it enter. And when they made a hole length of the splinter and a foot and half or two feet of depth, the hole was done deep with proportion that the rock is large, they fill up this powder hole, then stop it with plaster, leaving only one small opening at which they put a wick, and when they want to make play the mine they light this wick, withdraw themselves and safeguard themselves until she played and makes her effect.

Evaluation of a size per a tracer, detail of a drawing of Saverio Salvioni

The blocks which lay in career posed the same problem everywhere: although heavy and bulky, they were to join the stores of the king, in Paris to be implemented there. The density of the marble oscillates, according to the varieties, between 2.6 and 2.9 (its gravity specific to that of the water of 2,718). A block of mean size of 1 cubic meter or 27 cubic feet weighs gifts approximately 2700 kilos, considerable weight to move without risks and deteriorations. Only the liquid element made it possible to reduce the difficulties and the costs of such companies. Once achieved, its terrestrial course, which went from a few tens of meters as in Hèches to several miles as in Trets, the marble borrowed the water ways. In spite of immense difficulties, at the cost of incredible efforts and using means as ridiculous as sophisticated, the blocks arrived at Paris at the end of a true epopee.

Positioning of a block on the sledge called smooth, detail of a drawing of Saverio Salvioni

Smoothing of a block of marble, men then guide it with levers qe others ensure it using a cord sliding on a pile, detail of a drawing of Saverio Salvioni

Tools, lifting and transport

Clever machines

To raise and move heavy marble parts, machines as clever as curious were invented, like this swivelling crane with arm designed for the loading of column. Engraving extracted the mathematical and mechanical instruments of Jacques Besson 1594.

Tools of marble-mason's yard, encyclopaedia of Diderot and Alambet 1773

The ultimate transformation of the matter, entrusted to the monumental masons, raised of also old techniques and as complexes as those of the carriers. If all cannot be detailed, the cutting and the polishing of the panels are worth to be exposed, because they offer a summary outline of the art of the marble-mason's yard. To polish, or to reform all that can be against exactitude, with the purity and the elegance of the style, gives to the marble its ultimate brilliant aspect of a plain and luminous language, if appreciated in the palaces of God and the men.

The shaping of the marbles after flow always obeyed the same principle: to approach the plan or the form by an increasingly precise roughing then to refine and polish. The clothes industry of plates was the most common operation, because they could then be output in multiple panels, tables or stringcourses, suited to many employment. It was thus necessary to saw the blocks and slices thicknesses determined, which required particular competences, under penalty of important losses.

Raising, or put flat, was done with the double point, the gradine, then with the chisel, on the plates and small parts where it was necessary to slice the defects and asperities without striking too hard. For the full or stronger parts and for the final approach, one used the bush-hammer or the marteline, with which surfaces finely were studded and linked.

polishing, in the monumental masons, was carried out by the apprentices and the blue-collar workers in the family workshops, it was carried out by women and children. It was carried out like sawing by friction, but it was necessary to pass from coarse abrasives, which sandpapered or ate the parts, to finer which glossed them. In addition to siliceous sand, it could be a question of stones to be sharpened and sandstone initially, of emery then.

In Paris, the blocks were sawn in the stores of the king, by blue-collar workers under the orders of the director or with the expenses of the monumental masons

With bets the blocks were sawn in the stores of the king, by blue-collar workers under the orders of the director or with the expenses of the monumental masons, then there or in workshop, they were profiled, carved and polished, transformed into capitals, planks, cornices, vases balusters, chimneys, casings, furnace bridges, panels, flagstones or squares, like illustrates it this engraving of the encyclopaedia of Diderot and Alembert of 1773, presenting the store nearest to Louvre.

Sketch of a carriage builds in 1820 for the transport of a column of almost 7 meters length since the careers of Caunes. An attachment of eight oxen was envisaged on the dish.