In Greek mythology Hephaestus is said to be the only ugly god among Olympians, but why was this the case? I know he was born this way and later thrown of Olympus by Hera, but as a god he should've had the ability to change his appearance. So why didn't he just changed himself into being beautiful?
Hephaestus’ ugly appearance and lameness is taken by some to represent peripheral neuropathy and skin cancer resulting from arsenicosis caused by arsenic exposure from metalworking.
Bronze age smiths added arsenic to copper to produce harder arsenical bronze, especially during periods of tin scarcity. Many Bronze Age smiths would have suffered from chronic arsenic poisoning as a result of their livelihood. Iaia, Cristiano. (2013). Smiths and Smithing in Bronze Age 'Terramare'.
Consequently, the mythic image of the lame smith is widespread as will be explained later.
As Hephaestus was an iron-age smith, not a bronze-age smith, the connection is possibly one from ancient folk memory.
There is certainly no direct reference to any of these diseases in the ancient literature, and the best evidence for the possibility that recognizable arsenic toxicity existed is the indirect inference that may be drawn from the history of usage.
So far as other evidence for chronic metal poisoning is concerned it is only possible to draw conclusions in the manner that has been attempted here-that is, based on the probability of exposure estimated from a consideration of the processes and materials.
A common effect of chronic arsenic poisoning is dermatitis and hyperkeratosis sometimes associated with arsenical melanosis, which may lead to the development of skin cancer. These symptoms would have been readily and obviously associated with arsenic exposure.
In the long term another important manifestation of chronic arsenic poisoning is the development of a peripheral neuritis which may lead to weakness in the legs and feet.
In this connection it should be noted that the patron gods of craftsmen such as the Greek Hephaistos, Roman Vulcan, Teutonic Wieland/Wayland/Völundr, and the Finnish Ilmarinen are all lame. Such a widespread association of a particular symptom with a single occupation (smithing and craftwork) has led to the suggestion that this could have resulted from arsenical neuropathy.
There are two possible techniques for the gilding of copper and silver using mercury. In the first the surface of the base metal object is amalgamated by rubbing mercury on to it followed by the application of gold leaf. In the second, used by the Greeks, a prepared gold mercury amalgam is spread over the base metal surface. In either case pretreatment with a mercury salt is helpful and the final stage is to heat the metal to evaporate the mercury leaving a continuous and strongly adherent film of gold on the surface.
Other metals also form amalgams with mercury, the saturated weight percentage solution (at 20°C) being 2-15% for zinc, 0-61% for tin, and 1 3% for lead compared with 0-00032% for copper. There is a considerable likelihood of a solution of the first three metals spoiling the final gilding. In the case of lead, which is concentrated as globules on the surface rather than in solution in the copper, melting occurs at a temperature below the boiling point of mercury. For these reasons gilding was confined to low tin bronzes that were lead free or pure copper.
The entire process is fraught with the potential for mercury poisoning, exposure being a virtual certainty during both the refining of mercury and the final stage gilding.
Civilization before Greece and Rome. H. W. F. Saggs (I was unable to procure a free down-loadable for everyone to read)