The lime furnace

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Blows of ham­mers blare in the val­ley. A thick black smoke glides above the for­est. Some nights a week, strange lights light the sky.

In small careers of lime­stones locat­ed in the side of the moun­tain­side of the cal­care­ous blocks of the rocky wall are extract­ed. These blocks are then crushed and pre­pare for the trans­port for the oven with lime. Big trees are slaugh­tered and of the fire­wood is picked up. Raw mate­ri­als are trans­port­ed to the oven with lime where reigns an intense activ­i­ty.

We are in Roman epoch, in 65 before JC. The Romans intro­duced the lime as equip­ment of build­ing into our regions, his pro­duc­tion is made in an almost indus­tri­al way. The lime is used in the build­ing as socia­ble, dis­solved in the water it serves as a basis for the man­u­fac­ture of mor­tar and of con­crete. It is also used to whiten walls.

SE_03_KO01s

Work­ers con­struct the oven in one be sev­er­al metres deep, do a gallery of heat­ing there and set up a strong arch which must car­ry about 20 tons of cal­care­ous rocks. Cir­cu­la­tion of air is envis­aged and the cal­care­ous rocks are put down with cau­tion in sev­er­al lay­ers in the oven.

The fire is final­ly light­ed after sev­er­al days of exhaust­ing job. As soon as the embers illu­mi­nate the arch, the men stir the late because the lime­stone must remain in a tem­per­a­ture about 1000 °. Plunged into the clouds of smoke, they cov­er the oven of straw and of a lay­er of humid loam, reg­u­lat­ing so in an unin­ter­rupt­ed way the’ cir­cu­la­tion of air. The fire must be fed reg­u­lar­ly dur­ing two days and three nights, when it uses about 30 cubic metres of wood.

At the end of cook­ing, the oven must get cold dur­ing sev­er­al days. Final­ly, chauliers can pick the fruits of their labour. They extract porous and light white pieces of quick­lime of the still luke­warm oven. There is not more than about the half of the mass of ini­tial cal­care­ous stone. The lime is crushed in pow­der and trans­port­ed towards the con­struc­tion sites of build­ing. The oven is pre­pared for a new cook­ing.”

SE_03_KO02sThe relics of the lime fur­nace of Sen­nin­gen tell us how­ev­er anoth­er sto­ry: the fire was put out in a pre­ma­ture way and the process of cal­ci­na­tion was stopped. Was it fur­ther to a wood­en lack’, was it due to the too much wet wood, was it fur­ther to a seep­age of water dur­ing a big storm or fur­ther to a col­lapse of the arch of the oven? All job was in vain. The part­ly cal­cined lime, react­ed with water and humid­i­ty and knit­ted togeth­er in a big inert block. The relics of the oven were pro­tect­ed by its rocky tomb dur­ing almost two mil­len­ni­ums, it was only dis­cov­ered in 1938 dur­ing work of road build­ing.

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