Hephaestias in Galen's time, 167 AD

It is Galen during his visit to Hephaistias, in 167AD, who gives an insightful account of the method by which the Lemnian earth (LE) was extracted and processed (De Simpl. Med.,xiii, 246-248). Its colour was clearly red since it was referred by some as "Lemnia miltos" but differed from this in not leaving a stain when handled (Galen in Brock 1929, 192). Galen was particularly curious to verify this last point. "I thought well to inquire whether there was no tradition of goat's blood being mixed with the earth. All who heard this question of mine laughed, and they were not mere chance individuals, but people well informed about the whole history of the locality as well as in other matters"(Galen, in Brock 1929, 194). Galen distinguished three varieties of LE: a) the first (the medicinal one) was handled by the priestess herself, the second, also red, was used by builders (presumably as a pigment), the third for the cleaning of wool and other garments (Galen, xiii, 247). Fuller's earth is calcium montmorillonite or, in industrial minerals parlance, a bentonite with a vast range of applications in the modern world. Kimolian and Samian earths appear also to have been bentonitic clays.

Kostinas in Belon's time, 1543 AD

It was first on the Trojan war hero philocletes, that the priests of Hephaestus applied the LE, curing him of an unbearable stench and pain of hiw wound inflicted by the poisonous Hydra. Galen was so convinced of its effectivenessthat he reports enthusiastically "I had no hesitation myself in testing the medicine, and I took away (back to Rome) twenty thousands seals". Fourteen centuries later, in 1543, Belon, the intrepid 16th century traveler and natural historian, visited Constantinople where, after making enquiries, he encountered 18 types of different marketed as Lemnian Earth. It soon became apparent to him that some debasing was taking place. Therefore, he engraved the "brand name" of the real LE sphragis in his book for the benefit of the medical world. More important perhaps from the modern researcher's point of view, is Belon's description of how to get to the extraction point, which, after visiting it, he says was near the ruins of Hephaestias. "From the corner of the castle (at Kostinas) we walked towards the hill which is not more than four arrow-shots away. Between the port and the hill there is a small chapel called St Saviour's, where the monks gather on the 6th of August, the date set for the extraction of the earth from its vein. After leaving the church and walking towards the hillcock we found two paths, one to the left and one to the right leading to two springs, one about one arrow-shot away from the other" (Belon in T-S 1986, 79). Now Belon was no archeologist and the ancient city of Hephaestias was not revealed until the late 19th century. Therefore he mistook the remains of the castle at Kostina's with those of Hephaestias. He was, however, right aboyt the tow springs, the one which runs all year round, called Phtheleidia. In the course of geological prospection, altered and weathered pyroclastic rock was observed in the crags about 20m NW of the spring. Some were intensely altered showing coloursfrom white to yellow and brown to red. X- ray diffraction analyses showed that clay minerals like montmorillonite and illite were the main components with crystoballlite, relict feldspar, quartz and alunite. Alunite, a potassium aluminium sulphate forming as the result of high temperature alteration of feldspathic volcanic rocks, is usuall associated with alum and sulphur. Alum, aluminium sulphate, was well known in antiquity for its medicinal properties but being particularly soluble, it would have bee washed by rain out of the high volcanic ground into the alluvial sediment in the fields below or into man-made traps. The Dutchman Joos van Ghistele who visited Lemnos in 1485 reports on one such "trap"(LE) is produced…in a pool which dries up every summer and is full of water in winter…a thick scum, variegetated in colour, forms on its surface (Hasluck and Hasluck 1929). It is concluded that the different "varieties" of LE earth with various textures (sticky, greasy and granural) and colours which are refered to by Galen are products of the same hydrothermal alteration aroynd the Phthleidia spring. In some types of rock the alunite predominates, in others the clay minerals, leading to its different properties and applications.

Samian Earth: the case of "colyriun" and "aster"

Although documentary evidence of the exploitation of Samian earth dates from the time of Theophrastus in the 4th century BC it is Pliny in c. 50 AD (Nat. Hist.) who details two distinct varieties. These are "colyrium" an eye salve and "aster" which was used as a soap as well as in medicines. Samian earth is described as a white, soft lightweight substance, clearly a valuable versatile material, a typical industrial mineral. The present search for Samian earth followed the suggestions of the Samiot geologist Karageorghiou (1947) and IGME geological maps, that the volcanic rocks in the vicinity of Platanos were the likely source. These rocks have been altered to a soft absorbent clay mineral known as fullers' earth or bentonite. However, the medicinal value of this material is only limited, as an absorbent of toxic substances and it is likely that a second substance was present with more powerful medicinal and antiseptic properties. The existence of borate minerals, like collemanite identified in localities near Platanos point to the special substance being a soluble borate, well established ingredient in modern pharmaceutical products. Therefore it is suggested that Pliny's colyrium contains borate as the active ingredient while aster was a clay used as fullers' earth.