Hello to all
we often hear about the gravity or density test to determine the silver content of an item.
The theory is clear and simple, but putting it into practice is another matter.
In fact, I have never found with a gravity test the exact result prescribed by the hallmark.
Obviously I made ​​some mistake, perhaps in the weight reading (I use a scale for chemist ), perhaps in some other passage that escapes me.
In order to avoid the pitfalls of the method, I ask for help to those who are experienced.
For example, I find it difficult to suspend a tray or a ladle in a horizontal position. On the other hand, suspend these objects in a vertical position implies a huge water container.
I'd be glad to know in detail with what equipment and what methods experts perform the test in these cases.
Any help will be greatly appreciated.
Regards
Amena
Gravity test
Re: Gravity test
You are actually talking about specific gravity calculation.
It is explained in details here.
http://www.attilacoins.com/Calculate_Sp ... y_coin.asp
On the other hand, I can understand it`s used for coins to keep them safe from destroying patina. Or small gilded objects. But trays and ladles etc. can be easily tested with acids after filing in inconspicuous place to make sure base metal is reached (if only silver plated). Or, rub your silver on the surface of the black stone
- Bright Red: Fine Silver
- Darker Red: 925 Silver
- Brown : 800 Silver
- Green : 500 Silver
- Yellow: Lead or Tin
- Dark brown: Brass
- Blue: Nickel
But if you insist on specific gravity you really need a huge container for distilled water and very precise measurements.
It is explained in details here.
http://www.attilacoins.com/Calculate_Sp ... y_coin.asp
On the other hand, I can understand it`s used for coins to keep them safe from destroying patina. Or small gilded objects. But trays and ladles etc. can be easily tested with acids after filing in inconspicuous place to make sure base metal is reached (if only silver plated). Or, rub your silver on the surface of the black stone
- Bright Red: Fine Silver
- Darker Red: 925 Silver
- Brown : 800 Silver
- Green : 500 Silver
- Yellow: Lead or Tin
- Dark brown: Brass
- Blue: Nickel
But if you insist on specific gravity you really need a huge container for distilled water and very precise measurements.
Re: Gravity test
Hi AG2012,
I'm afraid I could not agree with you less. Acid testing is unreliable and destructive. Just imagine what would happen if everyone whose hands that piece of silverware passed through were to adopt the same attitude, filing lumps out of it. I've seen too many fine pieces that have been ruined by Philistines with a file and a bottle of acid. Would you take paint scraper to an Old Master painting? Would you chip the glaze off a fine item of porcelain? Of course not, so why would you want to take a file to a piece of silverware and damage it forever?
Specific gravity testing is harmless to the item, if preformed correctly and under the right conditions it is very accurate. Give your acid kit to a smelter, they are the only people that it should be of any use to.
Trev.
I'm afraid I could not agree with you less. Acid testing is unreliable and destructive. Just imagine what would happen if everyone whose hands that piece of silverware passed through were to adopt the same attitude, filing lumps out of it. I've seen too many fine pieces that have been ruined by Philistines with a file and a bottle of acid. Would you take paint scraper to an Old Master painting? Would you chip the glaze off a fine item of porcelain? Of course not, so why would you want to take a file to a piece of silverware and damage it forever?
Specific gravity testing is harmless to the item, if preformed correctly and under the right conditions it is very accurate. Give your acid kit to a smelter, they are the only people that it should be of any use to.
Trev.
Re: Gravity test
Yes, there are pieces to handle carefully and in inexperienced hands filing off even a fraction of millimeter can be disastrous, particularly if silver is gilded or with old patina.On the other hand, it`s no big deal to test e.g. trays, ladles, teapots etc with acid; superficial longitudinal filing only with jeweler`s files, then sandpapering with the finest grit size, polishing and buffing is virtually harmless in experienced hands.The point is people simply do not know how to do it properly. After some time when I forget where I did it I cannot recognize where it`s done. But, to each his own; how can I test teapots with wooden handles or ivory parts well riveted?
Re: Gravity test
Hi AG2012,
99% of people that use acid testing are doing it to determine whether an item is plated or not. You cannot file superficially in an attempt to get the answer, you have to destroy the surface to break though to the possible base metal. Sandpapering, polishing and buffing cannot bring the item back to its former condition, even re-plating cannot do that, the item is now damaged forever.
Trev. (Apologies to Amena for going off topic.)
99% of people that use acid testing are doing it to determine whether an item is plated or not. You cannot file superficially in an attempt to get the answer, you have to destroy the surface to break though to the possible base metal. Sandpapering, polishing and buffing cannot bring the item back to its former condition, even re-plating cannot do that, the item is now damaged forever.
Trev. (Apologies to Amena for going off topic.)
Re: Gravity test
In principle I agree with Ag 2012, and often use the acid test with the precautions described by him.
I must say that the liquid that I use, is not as smart as the one described by AG2012 (and I would be very interested to know the brand): It is very difficult to distinguish the purity from the color that you get with my reagent, also there is no reaction with nickel and tin.
But the reason I tackled the tricky test of gravity, comes from the fact that I found an old Italian ladle that has a hallmark very interesting, not mentioned in the books.
The laboratory can not perform the x-ray test due to the size of the ladle, so I decided groped the method of gravity test.
The results I got testing ladles with purity guaranteed by hallmarks, were always lower than expected, also much lower.
I then tried to make the test with ingots of pure silver, to check my measurement system, and I came across a paradox.
Two of the bars tested gave results consistent with weighing errors (specific weights around 10.5) but an ingot of Metalli Preziosi Spa of Paderno Dugnano, gave a truly absurd result: a specific gravity of 8.75 g / cc.
I thought I made a measurement error, so I repeated the test with three different weighing scales, always getting the same result. Anyhow, the ingot of 250 grams displace a volume of 28.6 cc of water, against a displaced volume expected to be about 23.8 cc; there is a difference of 4,8 cc that you can approximately verify measuring the ingot with the gauge : 1,24 X 3,71 X 6,3 = 28,98.
It is impossible to make a so great measurement error.
The Metalli Preziosi Spa was closed for failure many years ago, so I could not ask for information directly from the manufacturer.
I then assumed that the ingot was fake, just silver plated, but filing deeply a corner, the test with the acid, gives the red reaction.
I assumed that inside there was a core of another metal, coated with a discrete thickness of silver, so I sawed in two the ingot, which turned out to be homogeneous, silvery white, and gives an intense red reaction on the whole internal surface, and also the reaction with nitric acid is identical to that you get with the ingots of silver 999.
I also repeated the density test on the two pieces obtained, which obviously are not identical, and got still a density of approximately 8.7 g / cc, which excludes the possibility of air bubbles.
At this point I don’t know what to think, on the one hand the test with the acid ensures that it is silver, the other side the gravity test excludes that it is silver.
As soon as possible I will submit the ingot at the x-ray test and post the result.
Amena
I must say that the liquid that I use, is not as smart as the one described by AG2012 (and I would be very interested to know the brand): It is very difficult to distinguish the purity from the color that you get with my reagent, also there is no reaction with nickel and tin.
But the reason I tackled the tricky test of gravity, comes from the fact that I found an old Italian ladle that has a hallmark very interesting, not mentioned in the books.
The laboratory can not perform the x-ray test due to the size of the ladle, so I decided groped the method of gravity test.
The results I got testing ladles with purity guaranteed by hallmarks, were always lower than expected, also much lower.
I then tried to make the test with ingots of pure silver, to check my measurement system, and I came across a paradox.
Two of the bars tested gave results consistent with weighing errors (specific weights around 10.5) but an ingot of Metalli Preziosi Spa of Paderno Dugnano, gave a truly absurd result: a specific gravity of 8.75 g / cc.
I thought I made a measurement error, so I repeated the test with three different weighing scales, always getting the same result. Anyhow, the ingot of 250 grams displace a volume of 28.6 cc of water, against a displaced volume expected to be about 23.8 cc; there is a difference of 4,8 cc that you can approximately verify measuring the ingot with the gauge : 1,24 X 3,71 X 6,3 = 28,98.
It is impossible to make a so great measurement error.
The Metalli Preziosi Spa was closed for failure many years ago, so I could not ask for information directly from the manufacturer.
I then assumed that the ingot was fake, just silver plated, but filing deeply a corner, the test with the acid, gives the red reaction.
I assumed that inside there was a core of another metal, coated with a discrete thickness of silver, so I sawed in two the ingot, which turned out to be homogeneous, silvery white, and gives an intense red reaction on the whole internal surface, and also the reaction with nitric acid is identical to that you get with the ingots of silver 999.
I also repeated the density test on the two pieces obtained, which obviously are not identical, and got still a density of approximately 8.7 g / cc, which excludes the possibility of air bubbles.
At this point I don’t know what to think, on the one hand the test with the acid ensures that it is silver, the other side the gravity test excludes that it is silver.
As soon as possible I will submit the ingot at the x-ray test and post the result.
Amena
Re: Gravity test
I think you should look for an error in displaced volume of water.Even if the measuring container is well calibrated it`s not easy to read, particularly if it`s made of plastic and not laboratory glass.
It`s probably better to suspend an object and measure the difference of weight when submerged, but then you need a suspension scale.
Brw. volume calculation of the ingot based on its dimensions is NOT precise because it`s NOT a perfect rectangular cuboid.
It`s probably better to suspend an object and measure the difference of weight when submerged, but then you need a suspension scale.
Brw. volume calculation of the ingot based on its dimensions is NOT precise because it`s NOT a perfect rectangular cuboid.
Re: Gravity test
Maybe I was not clear.
I calculated the difference in weight when the ingot was suspended in air then in water, with a suspension scale and that is the displaced volume of 28,6 cc that I measured.
Certainly the ingot is not perfectly rectangular and the volume calculated is not accurate, in fact I wrote "that you can verify approximately measuring the ingot with the gauge"
However, the difference between the displaced volume expected 250 gr. / 10,49 = 23,83 cc and the one I detected is about 4.8 cc. In other words an ingot perfectly parallelepiped should have, for example, these measures
1.24 X 3.71 X 5.18 = 23.83
the difference is too large to think of a mistake.
Also, looking for news on the Internet, I found a message from SILVERFOX at this address
http://www.finanzaonline.com/forum/inve ... to-36.html
dated October 2010, which reads
“I recently bought some silver bullion as an investment. I had some doubt about the authenticity of some pieces marked "Silver 999/1000 Granted by Metalli Preziosi SpA Paderno Dugnano Milan -" since they were larger than those of Degussa of the same weight . Even the color did not convince me at all. The acid test showed that it was silver. But I was not convinced. Who sold it to me said that there was no problem, I could do the checks I want and, if anything is wrong, I would have changed. At home I built a rudimentary hydrostatic balance to determine specific gravity. The result was obvious: by measuring several pieces I found a specific gravity of about 8.7 g / cm 3!”
So I think that we can not only think of a mistake
I calculated the difference in weight when the ingot was suspended in air then in water, with a suspension scale and that is the displaced volume of 28,6 cc that I measured.
Certainly the ingot is not perfectly rectangular and the volume calculated is not accurate, in fact I wrote "that you can verify approximately measuring the ingot with the gauge"
However, the difference between the displaced volume expected 250 gr. / 10,49 = 23,83 cc and the one I detected is about 4.8 cc. In other words an ingot perfectly parallelepiped should have, for example, these measures
1.24 X 3.71 X 5.18 = 23.83
the difference is too large to think of a mistake.
Also, looking for news on the Internet, I found a message from SILVERFOX at this address
http://www.finanzaonline.com/forum/inve ... to-36.html
dated October 2010, which reads
“I recently bought some silver bullion as an investment. I had some doubt about the authenticity of some pieces marked "Silver 999/1000 Granted by Metalli Preziosi SpA Paderno Dugnano Milan -" since they were larger than those of Degussa of the same weight . Even the color did not convince me at all. The acid test showed that it was silver. But I was not convinced. Who sold it to me said that there was no problem, I could do the checks I want and, if anything is wrong, I would have changed. At home I built a rudimentary hydrostatic balance to determine specific gravity. The result was obvious: by measuring several pieces I found a specific gravity of about 8.7 g / cm 3!”
So I think that we can not only think of a mistake
Re: Gravity test
Hello,
I think you have disclosed a counterfeit ingot. Faked platinum and gold ingots are also circulating. Having in mind high prices and increased demand, there is huge profit in this; if silver is decreased from .999 to .900 it’s 10%. At least it`s silver;platinum bars are NOT platinum at all.
As for genuine old silver do not worry much if it’s properly marked and well made; a few % less silver does not matter, really. Their methods of making silver alloys were not perfect and testing, either.
This is what a buyer said:
``I bought a 100 oz Johnson Matthey silver bar on ioffer web site.The bar look real, but when I sent it to APMEX to sell they tested it and told me it was fake.
PLEASE DO NOT BUY ANY GOLD OR SILVER FROM IOFFER WEB SITE. These bars are coming from China. The bar I received had all the correct logos and even had a serial no on the bar. When I purchased the bar on ioffer I did not know that bar would be coming from china.
Be careful only buy your gold and silver from someone you trust. ``
Have a nice Sunday
I think you have disclosed a counterfeit ingot. Faked platinum and gold ingots are also circulating. Having in mind high prices and increased demand, there is huge profit in this; if silver is decreased from .999 to .900 it’s 10%. At least it`s silver;platinum bars are NOT platinum at all.
As for genuine old silver do not worry much if it’s properly marked and well made; a few % less silver does not matter, really. Their methods of making silver alloys were not perfect and testing, either.
This is what a buyer said:
``I bought a 100 oz Johnson Matthey silver bar on ioffer web site.The bar look real, but when I sent it to APMEX to sell they tested it and told me it was fake.
PLEASE DO NOT BUY ANY GOLD OR SILVER FROM IOFFER WEB SITE. These bars are coming from China. The bar I received had all the correct logos and even had a serial no on the bar. When I purchased the bar on ioffer I did not know that bar would be coming from china.
Be careful only buy your gold and silver from someone you trust. ``
Have a nice Sunday
Re: Gravity test
Well, I submitted the ingot to the x-ray test, and they have found silver 999.
I could not believe it, so I also submitted to the cupellation assay.
The result was silver 999 once again.
The ingot is definitely pure (999) silver
I bought an Ohaus scale, and I did the tests again and again with this scale.
For one of the two pieces I found density from 8.85 g / cc to 8.87 g / cc ; for the other, density from 8.70 g / cc to 8,71g / cc
So this is certainly an ingot of pure silver and has a specific weight definitely less than 9 g / cc.
There must surely be a metallurgical explanation to this fact, that for now I do not know and I will continue to seek.
I will post any news on the topic, and I'll be happy to have any suggestions.
I could not believe it, so I also submitted to the cupellation assay.
The result was silver 999 once again.
The ingot is definitely pure (999) silver
I bought an Ohaus scale, and I did the tests again and again with this scale.
For one of the two pieces I found density from 8.85 g / cc to 8.87 g / cc ; for the other, density from 8.70 g / cc to 8,71g / cc
So this is certainly an ingot of pure silver and has a specific weight definitely less than 9 g / cc.
There must surely be a metallurgical explanation to this fact, that for now I do not know and I will continue to seek.
I will post any news on the topic, and I'll be happy to have any suggestions.
Re: Gravity test
As I said in my last post, I continued the research on the "mystery" of the "light" bullion.
I found that the phenomenon was not unknown, and that a silversmith who had some of these "light" ingots, has used them in the manufacture of objects, without finding any abnormality in the processing and purity.
I then did a test and I melted a small part of the ingot.
I again measured the density of the piece obtained and found a value greater than 10 g / cc.
The piece is very small and therefore the measurement error can be greater in percentage, but it is certain that the density has increased dramatically.
An explanation of the fact could be related to properties of melted pure silver to absorb large amounts of oxygen, which releases during cooling.
I can’t give an exact explanation of the phenomenon yet, but I'm beginning to doubt about the validity of the method of the test of gravity.
Any opinion will be welcome.
Amena
I found that the phenomenon was not unknown, and that a silversmith who had some of these "light" ingots, has used them in the manufacture of objects, without finding any abnormality in the processing and purity.
I then did a test and I melted a small part of the ingot.
I again measured the density of the piece obtained and found a value greater than 10 g / cc.
The piece is very small and therefore the measurement error can be greater in percentage, but it is certain that the density has increased dramatically.
An explanation of the fact could be related to properties of melted pure silver to absorb large amounts of oxygen, which releases during cooling.
I can’t give an exact explanation of the phenomenon yet, but I'm beginning to doubt about the validity of the method of the test of gravity.
Any opinion will be welcome.
Amena
Re: Gravity test
Hi Amena
I was eagerly waiting how the story continues. I think that the community does not reply is not ignorance. We simply have no answer. In my universe, only two possibility exist: The Ingot is fake, and the silver content is less than 100%. Or there is a mistake with the gravity test. No third possiblity like 100% silver with a lower density. So I was studying your post, but could not find anything unlogical in your reasoning. So, I have no anser yet. Except, somwehere must be a mistake.
Kind regards
Jörg
I was eagerly waiting how the story continues. I think that the community does not reply is not ignorance. We simply have no answer. In my universe, only two possibility exist: The Ingot is fake, and the silver content is less than 100%. Or there is a mistake with the gravity test. No third possiblity like 100% silver with a lower density. So I was studying your post, but could not find anything unlogical in your reasoning. So, I have no anser yet. Except, somwehere must be a mistake.
Kind regards
Jörg
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AngusAardvark
- Posts: 37
- Joined: Sat Feb 07, 2015 3:14 am
- Location: Australia
Re: Gravity test
Intriguing. I wonder if somehow the ingots were produced by a very active process comparable to whipping eggs so there is a very very fine bubble network within the silver. When you remelt the silver this is destroyed. Shame the firm has disappeared.
Re: Gravity test
Hello Angus
I'm glad for your interest.
The characteristic that I mentioned above to absorb large amounts of oxygen, is a natural property of pure molten silver that does not require "a very active process comparable to whipping eggs". Exchanging views with a professor of metallurgy, it seemed that the focus should be on the possibilities that this oxygen has not been released or not completely released during cooling.
It must be said that the "heavy" ingots (density of about 10.5 g / cc) are manufactured by rolling and subsequent coinage, while that "light" one seems manufactured by die casting.
For now there are only guesses and I do not know what other test I could do to try to give a solution to this mystery.
Regards
Amena
I'm glad for your interest.
The characteristic that I mentioned above to absorb large amounts of oxygen, is a natural property of pure molten silver that does not require "a very active process comparable to whipping eggs". Exchanging views with a professor of metallurgy, it seemed that the focus should be on the possibilities that this oxygen has not been released or not completely released during cooling.
It must be said that the "heavy" ingots (density of about 10.5 g / cc) are manufactured by rolling and subsequent coinage, while that "light" one seems manufactured by die casting.
For now there are only guesses and I do not know what other test I could do to try to give a solution to this mystery.
Regards
Amena
-
AngusAardvark
- Posts: 37
- Joined: Sat Feb 07, 2015 3:14 am
- Location: Australia
Re: Gravity test
Ah yes.
I see on further reading that oxygen is highly soluble in liquid silver and normally is expelled when cooling but if somehow the cooling happens without expelling the oxygen you might get the results you have seen.
I see on further reading that oxygen is highly soluble in liquid silver and normally is expelled when cooling but if somehow the cooling happens without expelling the oxygen you might get the results you have seen.
Re: Gravity test
Nice and interesting post. Im gonna try to help you out with my bad english.
First thing I noticed was that you run a X-ray test on a ingot. This test can be run for almost any material and it is about difraccion of the particules irradiated by X-rays. When you do this test, you need a sample. The key is the sample you get from the hole piece you want to test. Saying this, if you want to test an ingot you need several samples, from the surface and deep inside the ingot.
If you make good samples of your item, you will have an accurate result. Each phase of a material has a specific refraction and thats what the Xray method dectecs, the "phase". For example, you can test Al2O3-alumina (aluminium oxide) which is a material but you may find diffrent phases of it and each of this phases will be detected by X-ray test. However, silver as metal is one phase so if the x-ray dectected 99.99% of silver means that in that sample, was no other phase or material than silver. Silver oxide exists when you test the surface of the ingot you must find it because its a diffrent phase.
I wonder if you ingot could have a burble inside called "closed porosity" which cannot be filled by water and can affect your specific gravity test.
First thing I noticed was that you run a X-ray test on a ingot. This test can be run for almost any material and it is about difraccion of the particules irradiated by X-rays. When you do this test, you need a sample. The key is the sample you get from the hole piece you want to test. Saying this, if you want to test an ingot you need several samples, from the surface and deep inside the ingot.
If you make good samples of your item, you will have an accurate result. Each phase of a material has a specific refraction and thats what the Xray method dectecs, the "phase". For example, you can test Al2O3-alumina (aluminium oxide) which is a material but you may find diffrent phases of it and each of this phases will be detected by X-ray test. However, silver as metal is one phase so if the x-ray dectected 99.99% of silver means that in that sample, was no other phase or material than silver. Silver oxide exists when you test the surface of the ingot you must find it because its a diffrent phase.
I wonder if you ingot could have a burble inside called "closed porosity" which cannot be filled by water and can affect your specific gravity test.
Re: Gravity test
Hi Dael
regarding the xray test, I have not personally witnessed the test and I did not request an official written certificate. I just handed over the two pieces of the ingot sawed in two, saying to the head of the laboratory that if it was necessary, he could do whatever he wanted on the surface of the ingot to remove any oxide coatings or other, and the next day I got the response verbally .
On the other hand the purity of the metal was also confirmed by the test of cupellation.
The solution is then no doubt in an air inclusion.
I have mirror polished one of the surfaces obtained by sawing in two the ingot and I observed with a powerful lens, but I could not see any trace of bubble
It must treat therefore of microscopic bubbles,or micro porosity which I do not know how they can be generated.
Thanks anyway of the interest
Regards
Amena
regarding the xray test, I have not personally witnessed the test and I did not request an official written certificate. I just handed over the two pieces of the ingot sawed in two, saying to the head of the laboratory that if it was necessary, he could do whatever he wanted on the surface of the ingot to remove any oxide coatings or other, and the next day I got the response verbally .
On the other hand the purity of the metal was also confirmed by the test of cupellation.
The solution is then no doubt in an air inclusion.
I have mirror polished one of the surfaces obtained by sawing in two the ingot and I observed with a powerful lens, but I could not see any trace of bubble
It must treat therefore of microscopic bubbles,or micro porosity which I do not know how they can be generated.
Thanks anyway of the interest
Regards
Amena
Re: Gravity test
I have been for more than 30 years in the jewelry business.
And I have seen almost everything....
You can not rely only on acid tests, gravity testo or even spectometer tester.
There are many gold and silver bars, with a thick "skin" of the metal, but with a different material inside (let's say tungsten in the case of gold bars).
So, further than the uper said test, it is always necessary to know where the ingot comes from.
Just my two cents.
And I have seen almost everything....
You can not rely only on acid tests, gravity testo or even spectometer tester.
There are many gold and silver bars, with a thick "skin" of the metal, but with a different material inside (let's say tungsten in the case of gold bars).
So, further than the uper said test, it is always necessary to know where the ingot comes from.
Just my two cents.
Re: Gravity test
Hello Abley
thanks,every cent counts.
I too had heard of bars with a skin of precious metal and other metal inside, and that's why I cut in two the ingot and I did all the tests on the surface obtained by sawing.
I must add that I continued my tests by calculating the density of 6 modern cutlery (after 1970) and 6 antique cutlery (before 1850).
In the case of the modern cutlery I got fairly consistent results and closest to the expected value of 10.17 for silver 800, in the case of the antique cutlery, who have a purity of 830, I found results always lower than 10.
I think the reason is that the modern cutlery are stamped items, while the old ones are cast and then may have air bubbles.
However, this experience has made me realize that the density of a piece of silver depends not only on the purity, but also on the manufacturing technique and so I abandoned the gravity test.
Best
Amena
thanks,every cent counts.
I too had heard of bars with a skin of precious metal and other metal inside, and that's why I cut in two the ingot and I did all the tests on the surface obtained by sawing.
I must add that I continued my tests by calculating the density of 6 modern cutlery (after 1970) and 6 antique cutlery (before 1850).
In the case of the modern cutlery I got fairly consistent results and closest to the expected value of 10.17 for silver 800, in the case of the antique cutlery, who have a purity of 830, I found results always lower than 10.
I think the reason is that the modern cutlery are stamped items, while the old ones are cast and then may have air bubbles.
However, this experience has made me realize that the density of a piece of silver depends not only on the purity, but also on the manufacturing technique and so I abandoned the gravity test.
Best
Amena
Re: Gravity test
Just a little fun fact.
I found on line this book of the year 1806
"If the specific gravity of the the gold and silver items in binary alloy can be used to determine their purity? "
Memory of Mr. Giovanni Fabbroni included in the Tome 13 of the Italian Society of Sciences"
Unfortunately, Mr. Fabbroni concludes on p. 30
"these facts are enough (in confirmation of earlier) to ascertain that the specific weight does not get along with the purity;and that you would use wrongly as as an indication of the same."
Regards
Amena
I found on line this book of the year 1806
"If the specific gravity of the the gold and silver items in binary alloy can be used to determine their purity? "
Memory of Mr. Giovanni Fabbroni included in the Tome 13 of the Italian Society of Sciences"
Unfortunately, Mr. Fabbroni concludes on p. 30
"these facts are enough (in confirmation of earlier) to ascertain that the specific weight does not get along with the purity;and that you would use wrongly as as an indication of the same."
Regards
Amena