for primary procedures
Al-Rāzī gave methods and procedures of coloring a silver object to imitate gold (gold leafing) and the reverse technique of removing its color back to silver. Also described was gilding and silvering of other metals (alum, calcium salts, iron, copper, and tutty, all being processed in a furnace with real fire), as well as how colors will last for years without tarnishing or changing.
Al-Rāzī classified naturally occurring earthly minerals into six divisions (Rashed, 1996):
I. Four spirits (Al-Arwāh, the plural of the Arabic word Rūh, which is best described in the Qur’an as an order of Allah):
1 mercury
2 sal ammoniac, NH4Cl
3 sulfur
4 arsenic sulphide (orpiment, As2S3 and realgar, As4S4 or AsS)
Even though this classification has been often referred to as ‘ghosts that roam around the earth’, this translation is ill-conceived and defies Qur’anic logic. Correct meaning is these materials are the source materials as in essence. In our previous work, we have called it the ‘intangible’ (Zatzman and Islam, 2007; Khan and Islam, 2012; Islam et al., 2010; Islam et al., 2015).
The above list is meaningful. Each of these materials bears some significance in terms of sustainability and human health. In today’s society, mercury is known to be a toxic material with adverse effects on the body and unanimously portrayed as a toxic chemical with long-term implication, it is one of those rare metals that had time-honoured applications even in the ancient society (Iqbal and Asmat, 2012). This unique heavy metal, which is less toxic in its elemental form than in its compound form, has enjoyed both industrial and medicinal applications throughout history (Wong, 2001).
2.2.1 Mercury
From ancient times, the history of mercury has been connected with that of the medicine and chemistry (Block, 2001). Both sulphur and mercury are known to have been used in early civilizations in China, India and Egypt. Mercury has particular relevance to the history of science of both medicine and alchemy (Norn et al., 2008). Both sulphur and mercury have been used as disinfectants. In post Roman Catholic Church (RCC) Europe, mercury was first introduced by Muslim physicians and it was first mentioned in European literature in 1140 by Matthaeus Platearius, who recommended its use for treatment of syphilis as well as for treatment of wound and others (Block, 2001). On the medicinal side, mercury, in both its elemental and compound forms, has been used throughout history as a microbiocide (Weber and Rutala, 2001). However, ancient times had used only natural processes for extracting mercury. In this context, Figure 2.3 Summarizes how metals act within human bodies. This figure is adapted from Islam et al. (2016), who used the bifurcation to demonstrate that natural chemicals act the opposite way from unnatural chemicals, and Weber and Rutala (2001), who did not distinguish between natural processing and unnatural processing, settling instead for ‘essential’ and ‘non-essential’ varieties. Islam et al. (2015) as well as Islam (2014) contended that every naturally occurring chemical is beneficial at some concentration, beyond which it becomes toxic (see the top graph in Figure 2.2) On the other hand, what is perceived as non-essential (as per Weber and Rutala, 2001, most heavy metals are non-essential although there is almost yearly discovery that these metals are also essential, albeit at a very small concentrations. The concept that unnatural metals, i.e., the ones processed through non-sustainable techniques is inherently toxic to the organism is new but it answers all the question regarding how toxicity functions within an organic body. As discussed by Islam and Khan (2018), the presence of artificially processed metal is akin to introducing a cancer cell that continues to wreck havoc to the organism.
Figure 2.2 The usefulness of metal depends on its concentration as well as source
(Figure adapted from Islam et al., 2016 and Weber and Rutala, 2001).
In ancient times, only the upper graph of Figure 2.2 Existed because all processes were sustainable from both mass and energy perspectives (Khan and Islam, 2016). Today, it has become a common practice to lump chemicals that had been in use since the ancient time with those discovered in later era, for which there is no longer a natural processing technique available. For instance, many clinical studies have lumped cadmium, lead, mercury, thallium, bismuth, arsenic, antimony and tin in the same vein. Yet, cadmium was discovered in 1872 (just before the invention of electricity in 1979), thallium was discovered in 1861 whereas other metals were either used in their natural form (ore) or processed through natural means (e.g. open fire, natural additives). The first metal to be smelted in the ancient Middle East was probably copper (by 5000 BCE), followed by tin, lead, and silver. To achieve the high temperatures required for smelting, furnaces with forced-air draft were developed; for iron, temperatures even higher were required. Smelting thus represented a major technological achievement. Charcoal was the universal fuel until coke was introduced in 18th-century England (Islam et al., 2010).
Many forms of mercury exist in nature, including elemental mercury, inorganic mercury, and organic mercury (Weber and Rutala, 2001). From ancient times onward, organic mercury1 compounds have been used as antiseptics, antibacterials, fungicides and other disinfectants. These are highly toxic beyond very low concentration. It means their optimal concentration (Figure 2.2) is quite low. Beyond the optimal concentration, organic mercury can produce toxicity through skin absorption, ingestion, or inhalation. They are also associated with gastrointestinal, renal, and neurologic toxicity. Thimerosal (merthiolate; 2(9-ethylmerucrio-thio) benzoic acid sodium salt has been widely used as a bactericide at concentrations of 0.001% to 0.1%. It has also been used as preservatives in pharmaceuticals and cosmetics, including in vaccines, eyedrops, contact lens cleaning and storage solutions, cosmetic creams, toothpaste, mouthwash, etc. (Van’t Veen and Joost, 1994). While this is widely recognized, few are aware of the fact that the chemicals that are used in modern industry are not chemicals that are naturally occurring, they are instead synthetic. Therefore, they are toxic even below the optimal concentration, meaning the lower graph of Figure 2.2 Should be consulted. This same principle also applies to mercury vapour. For instance, today’s mercury vapor lamps use an arc through vaporized mercury in a high-pressure tube to create very waves (of various wavelengths) directly from its own arc. This is different from fluorescent lightbulbs, which use the mercury vapor arc to create a weaker light that mainly creates UV light to excite the phosphors. This usage is just one of many alterations of original usage of mercury.
In Figure 2.3, relative output spectra of low- and medium pressure mercury arc lamps
