Chemical burns ancient times

Among the more unusual BCNO compounds is antimony oxide, which is used to fireproof toys, car seats, and airplane parts. The compound reacts with burning material to form a chemical layer that blankets and extinguishes the flame. In ancient times, the Egyptians mixed a compound of antimony and sulfur with fat to make kohl, a black cosmetic used to color eyebrows and line eyes with a dark ring. All living things seem to need a tiny bit of the... 

Processes such as the combustion of fuels, the refinement of ores into their component metals, and the corrosion of metals have been among the most familiar chemical reactions since ancient times. The nature of these reactions, however, remained a complete mystery throughout the Middle Ages and well into modern times. It was not until the discovery of oxygen in the 1770s that processes as familiar as burning wood could be explained. 

Treatment of the Raw Materials. Based on the field expedition to Mexico in 1981 and the subsequent mineralogical and chemical analyses of the collected clays and modern majolica, much more can be worked out on the technique of ancient Mexican majolica production. The low calcium content of the Valle Ware specimens points to the use of a noncalcareous clay. The observed mineralogical matching of these specimens with modern black clays from Puebla (SD 47 and SD 48) and ancient Pre-Columbian pottery (I-l, 1-2, SC 98, SC 99) suggests that these objects have been made from the locally available common red-burning volcanic clays, which were used extensively in Pre-Columbian time. There is no further evidence from microscopic inspection that supplementary addition of another material took place. These clays were therefore used, possibly after a sieving, as they have been found. 

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