In this visitor message I will be testing the new character limit of the VM system. The following is an excerpt from an essay I did for history class. This post contains 4000 characters says Word.
Ever since its discovery, metal and metal alloys have proved to be pivotal in the advancement of human technology and development. The Romans, with their dominion that spanned far in both time and space, made great use of the various techniques and materials throughout the world at that time to make better tools, better infrastructure, and better weapons.
Ancient metalworking techniques were based almost entirely on empirical discovery. Through countless attempts in trial and error, they developed techniques to achieve the results they wanted. It isn't known exactly when or how metals were first discovered, although there are many theories. Metal was discovered independently by many early civilizations, possibly with the first metal discovered being gold. Because it is a very inert element, gold is often found in its pure form in nuggets along riverbeds.
A majority of what we know about Roman metalworking techniques comes from Pliny's Natural History, which gives a sometimes incomplete but generally detailed description of the practices of the day. The rest comes from archaeological digs of roman forges, and analysis of what metal objects remain today. Pliny gives us an account of the production of bronze at Capua:
"it is smelted in a fire of wood, not of charcoal, and then poured into cold water and cleaned in a sieve made of oak, and this process of smelting is repeated several times, at the last stage Spanish silver lead being added to it in the proportion of ten pounds to one hundred pounds of copper: this treatment renders it pliable and gives it an agreeable colour of a kind imparted to other sorts of copper and bronze by means of oil and salt. " (masseiana.org, 2009)
In this context, "silver lead" refers to tin, which when mixed with copper in a 10:1 ratio produces bronze, a very useful alloy being stronger than the sum of its parts. There were seven elemental metals that were well known to the Romans: gold, silver, copper, tin (silver lead), iron, lead (black lead) and mercury. They were also able to produce several alloys, such as the bronze mentioned earlier, as well as brass and "Amalgam", an alloy of mercury and silver.
For improving the purity of copper, the Romans developed a delicate technique known as "poling", in which molten copper is stirred with poles of green wood. The escaping steam from the wood rises through the metal and bubbles to the surface, acting like a blast of air (Williams, 1987). This causes impurities in the copper such as oxides to rise to the surface, so that it can be taken off as slag.
There were also many techniques and measures to assay the quality of metals produced. There were two main tests used: heating the metal with fire, and scratching it with a touchstone. Test by fire is a simple method to determine if the gold someone is selling you contains base metals; if you heat it in a red-hot pan, the metal turns colour. If when cooled, the metal returns to the colour it was originally then the metal is pure. If it turns white, then it contains added tin. If it turns black, it contained added lead. The touchstone test was slightly more complicated, and involved scratching the metal with stones from a specific river and comparing the scratch with a sample of known purity. Thus, a relative estimate can be made of the metal's purity (Humphery, Oleson, & Sherwood, 1998). Tests such as this were often necessary, as it was not uncommon to find someone trying to pass off a base metal as something more valuable (much easier to do when there is a very loosely understood definition of what separates one metal from another). According to Pliny, some would coat a cheap metal l...
Ever since its discovery, metal and metal alloys have proved to be pivotal in the advancement of human technology and development. The Romans, with their dominion that spanned far in both time and space, made great use of the various techniques and materials throughout the world at that time to make better tools, better infrastructure, and better weapons.
Ancient metalworking techniques were based almost entirely on empirical discovery. Through countless attempts in trial and error, they developed techniques to achieve the results they wanted. It isn't known exactly when or how metals were first discovered, although there are many theories. Metal was discovered independently by many early civilizations, possibly with the first metal discovered being gold. Because it is a very inert element, gold is often found in its pure form in nuggets along riverbeds.
A majority of what we know about Roman metalworking techniques comes from Pliny's Natural History, which gives a sometimes incomplete but generally detailed description of the practices of the day. The rest comes from archaeological digs of roman forges, and analysis of what metal objects remain today. Pliny gives us an account of the production of bronze at Capua:
"it is smelted in a fire of wood, not of charcoal, and then poured into cold water and cleaned in a sieve made of oak, and this process of smelting is repeated several times, at the last stage Spanish silver lead being added to it in the proportion of ten pounds to one hundred pounds of copper: this treatment renders it pliable and gives it an agreeable colour of a kind imparted to other sorts of copper and bronze by means of oil and salt. " (masseiana.org, 2009)
In this context, "silver lead" refers to tin, which when mixed with copper in a 10:1 ratio produces bronze, a very useful alloy being stronger than the sum of its parts. There were seven elemental metals that were well known to the Romans: gold, silver, copper, tin (silver lead), iron, lead (black lead) and mercury. They were also able to produce several alloys, such as the bronze mentioned earlier, as well as brass and "Amalgam", an alloy of mercury and silver.
For improving the purity of copper, the Romans developed a delicate technique known as "poling", in which molten copper is stirred with poles of green wood. The escaping steam from the wood rises through the metal and bubbles to the surface, acting like a blast of air (Williams, 1987). This causes impurities in the copper such as oxides to rise to the surface, so that it can be taken off as slag.
There were also many techniques and measures to assay the quality of metals produced. There were two main tests used: heating the metal with fire, and scratching it with a touchstone. Test by fire is a simple method to determine if the gold someone is selling you contains base metals; if you heat it in a red-hot pan, the metal turns colour. If when cooled, the metal returns to the colour it was originally then the metal is pure. If it turns white, then it contains added tin. If it turns black, it contained added lead. The touchstone test was slightly more complicated, and involved scratching the metal with stones from a specific river and comparing the scratch with a sample of known purity. Thus, a relative estimate can be made of the metal's purity (Humphery, Oleson, & Sherwood, 1998). Tests such as this were often necessary, as it was not uncommon to find someone trying to pass off a base metal as something more valuable (much easier to do when there is a very loosely understood definition of what separates one metal from another). According to Pliny, some would coat a cheap metal l...