In the first half of 20th century, how was gold inspected for authenticity?
score:25
As Denis observed in the comments above, for many countries, gold would have been traded through securities in the first half of the twentieth century. In those cases the physical transfer of the gold would indeed have been the exception, rather than the rule. That said, there would undoubtedly have been a great many cases where gold was transferred as payment, and some form of metallurgical assay to ensure its purity would have been required.
Apart from a few modern techniques like X-ray fluorescence (XRF), most of the techniques used to assay gold were in use long before the twentieth century. (In any event, XRF - although non-detructive - can be fooled by surface treatments like gold-plating). The most likely techniques, however, would be using a "touchstone" or conducting a "Fire Assay".
In the example you give, where the gold was to be exchanged for the goods at the port, testing would probably have been carried out with a touchstone. The use of touchstones dates back to antiquity, and they remain in use to this day. These could easily distinguish between, for example, 14 carat and 24 carat gold (I've done it myself), and I read that experienced testers can achieve accuracies of better than 5%.
If a more accurate assessment was required, a Fire Assay may have been carried out on a sample from one or more of the ingots. This technique is destructive, but has been available since the sixteenth century (a version is mentioned in Agricola's De Re Metallica). I would very much doubt that a Fire Assay could have been carried out at the port though (unless specialist facilities were available there expressly for that purpose).
[One of the reasons that national mints introduced mint-marks on bullion from about the eighteenth century was to assure its quality and so eliminate the need for such testing].
Today, a fire assay on gold can achieve an accuracy of better than 0.05%. My reading of the text of A Manual of Assaying, by Arthur Stanley Miller, seems to suggest that similar accuracies would have been achievable when it was published in 1905.
Upvote:3
For smaller transactions, early 20th century literature has a lot of references of people biting into the gold. See more detail in this answer to a closely related question in the history section of Skeptics.SE.
Upvote:3
A classical test that does not seem to have yet been mentioned was a literal "acid test": the purported golden item is rubbed onto a stone, after which the mark is treated first with aqua fortis (nitric acid). True gold should not dissolve in it; a follow-up treatment with aqua regia should then dissolve the mark made, if the golden article is genuine. (See e.g. this.)
More post
- 📝 How did galleys battle?
- 📝 What was the attendance at the Isle of Wight Festival in 1970? Was it the largest gathering ever in the UK? If not, what was?
- 📝 What was the congressional level of support for Emancipation Proclamation?
- 📝 Why did Americans stop calling the Olympic basketball team the "Dream Team"?
- 📝 Do negotiations/concessions to dictatorial powers always bring them to wanting more?
- 📝 Examples of oppressive regimes which "loosened up" after winning destructive civil war
- 📝 How safe were ancient boats on the sea?
- 📝 Did the chariot drop in importance between bronze age Greece and the iron age Greece? Why, why not?
- 📝 Was there an alcohol abuse problem among monks and priests in the High Middle Ages in England?
- 📝 Downloadable/Printable 3D Model of Cylinder Seal
- 📝 Did Rome conquer the Parthian Empire during the conquests of Trajan?
- 📝 Who is this person on the picture?
- 📝 When were the baskets invented in Australia and America?
- 📝 What changed Japanese attitude to POWs in inter-war period?
- 📝 Did Christians ever use crucifixion as punishment?
- 📝 The Roman Legion Strength
- 📝 Was jealousy the cause of Ernst Winter's death?
- 📝 What was the first "fashion trend"?
- 📝 In France, 1916, would a soldier who was invalided out of the army, e.g. as an amputee, still get his army pay?
- 📝 Why did US Navy WW2 torpedoes detonate at the end of their run?
- 📝 What Insubordination Did Colonel Sanders Do With Prudential Life Insurance?
- 📝 How were servants to the Kaiser of Imperial Germany treated and where may I find more information on them?
- 📝 Where were visa documents invented?
- 📝 How can we be confident that Tacitus really wrote his Histories and Annals?
- 📝 What was the expected retirement age for men in Spain in 1936?
- 📝 Why is this column in Pompeii constructed in two parts?
- 📝 Allied assistance of the Soviets during WW2
- 📝 What is known about how many Ulfberht swords exist?
- 📝 Why did the start of the Roman consular year move?
- 📝 Has US ever unpegged USD from another country?
Source: stackoverflow.com
Search Posts
Related post
- 📝 In the first half of 20th century, how was gold inspected for authenticity?
- 📝 How common was smoking in first half of the 20th century?
- 📝 What was the reason of extreme anti-Communism in the first half of 20th century?
- 📝 How profitable was India for the British Empire in the 1800s?
- 📝 How was the linen weaving trade learnt in 18th century Scotland?
- 📝 How common was it for people to live 80+ years in the 17th century?
- 📝 How common was it for un-documented ships to bring settlers to the American colonies 1700-1750
- 📝 In the Soviet Union, how was payment enforced for public transportation?
- 📝 How did they measure speed in the 19th century so they could issue the first speeding ticket?
- 📝 How common was it for Americans to visit Europe in the late 19th century?
- 📝 How was the safety of allied leaders ensured in transportation for conferences during WW2?
- 📝 What was the first recorded instance of sex or violence being inappropriate for children to see?
- 📝 Why are the buildings built in classical style in the first half of the 19th century in Russia so frequently yellow-and-white - coloured?
- 📝 Was the enclosure responsible for the supply of factory workers in 18th and 19th Century England?
- 📝 What was the typical range of travel of a Pennsylvanian resident for everyday life in the late 18th early 19th Century Pennsylvania?
- 📝 How common was the German desire for revenge for the humiliation of 1918 armistice?
- 📝 How common was gun ownership by Londoners in the early 20th century?
- 📝 How difficult was Muraviev's amassing of troops for the forcing of the Treaty of Aigun, and what effects on development did it have?
- 📝 How did people 'park' their horse and buggy in early 20th century cities? How was theft prevented?
- 📝 How was the first official geographical border established in Europe?
- 📝 What was the average age of first marriage in 18th century Russia?
- 📝 In Montgomery, Alabama, how common was it to be arrested for sitting in the incorrect section of the bus?
- 📝 Was it widespread during the 17th and 18th Century for British country people to be evicted and replaced with more profitable agriculture?
- 📝 How long ago was the yo-yo first used as a weapon?
- 📝 How was the Karwendel railway important to Germany's plans for WW1?
- 📝 How common among Abolitionists was the goal of complete civil equality for Blacks?
- 📝 In the First Barbary War, how long was the USS Philadelphia aground?
- 📝 How were precise hand drawn illustrations copied between the 16th and 20th century in Europe?
- 📝 Was the Times of London available for sale in 19th century Singapore?
- 📝 How possible was it for colonizers to sail up the Paraná River to today's states of Paraná and São Paulo?