Glass Message Board
Glass Identification - Post here for all ID requests => Glass => Topic started by: Bernard C on May 20, 2006, 06:11:41 AM
-
It seems to me to be reasonable to use as your primary unit of length the unit that was in use by that glassworks at the time, with an alternative measure given in brackets for those of us today who are not used to the system. So, for example, all British glass other than the most modern should be measured in inches, with a metric measurement given as an alternative if it could be useful to some readers, thus:- 8" (20cm). This provides the link to measurements in contemporary material such as pattern books, trade catalogues and advertisements.
It also keeps us well away from loony statements like "The Davidson Column Vase was made in three sizes, 15cm, 20cm and 25.5cm", when we all know it wasn't, it was made in 6", 8", and 10" sizes, and only serves to confirm that the writer is very confused, a complete plonker, or (in Britain) a trained archaeologist*, or, quite possibly, all three.
You can go one step further and use italics to show derived lengths rather than measured lengths, so 8" (20cm) would show that the object was measured in metric only, and that the inch measurement was derived.
So, my question is what primary measurement system should I use for Venetian glass dating from c. 1895–1920? Were the Murano glassworks using the metric system then, or some earlier system? It seems logical to describe the height of my blue vase as 13.5cm (5¼"), but I could be technically incorrect.
In a more general sense, when did the metric system become widely accepted and used on the European mainland? ... and what systems did it replace?
Bernard C. 8)
* — Some years ago I saw the following written by an eminent archaeologist:
"Milestones are found along the road at intervals of 1610 metres".
Hard to believe, but it's true!
-
Hello Bernard,
I found this:
http://www.unc.edu/~rowlett/units/metric.html
It has some fantastic history about when the metric system was introduced. I am not sure, if they say which system was in place before this time, as I don't have time to read the whole article, as I am in a hurry to get packed etc.
Whilst I am in the UK, I will try to get a tape measure which has inches on it. I only have a cm tape, as that is what is for sale here in The Netherlands. Although, not knowing where a piece originates from, could cause problems for me :oops:
Which unit of measurement do I use first and which do I put in brackets or italics?
-
... Which unit of measurement do I use first and which do I put in brackets or italics?
Always the units that the glass was made in first, with other measures in brackets.
Thanks for the link. It shows that Italy was fully metric by the time my glass was made, so the height of my blue vase is quite properly given as 13.5cm (5¼") or just 13.5cm. Note that 13.5cm (5.25") is not correct, as it implies an unwarranted degree of precision, one of the two major problems of the metric system, the other being the relative scarcity of factors of 10 compared to 12.
Bernard C. 8)
-
Oh, and don't take me too seriously. If you are measuring a piece for IDing, whatever units of measurement suit you. If you know its origin and age, then it's best to stick to the above guidelines.
Bernard C. 8)
-
I think there are some other things to consider when giving measurements. Essentially I agree with you Bernard, one should use the units of length given by the manufacturing company.
However, I feel there are circumstances when a conversion is justified. Firstly, if the item(s) in question is already well known and sizes are accepted and in common use. For example, if say, a vase is well known as being a 6" vase - then it seems preferable to me to continue referring to it as such, even though the original maker sized it in centimetres.
Secondly, I think it depends on the "audience". I personally prefer (if am writing for a USA audience) to use the Imperial terms, for items made in mainland Europe. If circumstances warrant it, I would also use the original metric measurement.
Glen
-
As Metric is almost universally accepted as the standard form of measurement, most people reading threads in this forum will not be familiar with imperial. That would include almost everyone in Europe and most people in the UK under the age of 40.
For reasons of clarity, I think that metric measurements should be given precedence, with imperial dimensions supplied in brackets.
Not to ignore the measurements originally specified by manufacturers: the original unit of measurement should only be given precedence when referring to advertisements, publications or pattern books that are contemporary to the period when an item was made. In which case, measurements should be quoted from the original documentation and metric (or otherwise) conversions provided afterwards.
If you are not directly quoting from a document, but are still referring to sizes mentioned in a document, these should be stated in inverted commas e.g. "these vases, as mentioned in the original catalogue, were available in '8inch, 10inch and 12inch' heights". You would then provide a metric conversion in brackets.
-
... If you are not directly quoting from a document, but are still referring to sizes mentioned in a document, these should be stated in inverted commas e.g. "these vases, as mentioned in the original catalogue, were available in '8inch, 10inch and 12inch' heights". You would then provide a metric conversion in brackets.
No, David, the three measurements I cited in my original post were sizes, not heights. The actual measurements vary considerably, depending on whether the rims were flared or turned over (D'ed in Davidson terms).
Citing a metric measurement for a British-made item with an inch measurement in brackets is at best confusing. We are talking here about marrying primary printed and written source material with actual objects.
I can see that this topic is going to raise some interesting views. I do enjoy a good debate.
Bernard C.
-
No, David, the three measurements I cited in my original post were sizes, not heights. The actual measurements vary considerably, depending on whether the rims were flared or turned over (D'ed in Davidson terms).
I wasn't actually referring to your example, but giving an example of how measurements should be dealt with.
As I have already mentioned, when dealing with measuremnts mentioned by the original manufacturer, the original units should be given precedence. However metric conversions should be provided, so that those who do not understand imperial units can get an idea of the sizes being discussed.
If you refer to the size of a vase being 6" in a pattern book and supplement this with a size in cm (15.2), I can't see how that could be confusing. The sizes are equal to one another. Besides, if someone only has metric measuring devices, they will need conversions to compare dimensions with items they own.
In all other instances, such as describing a piece of glass for identification, metric units should be used, with imperial sizes given in brackets.
-
Most people do use the metric system today so it becomes a historical quirk to continue with imperial as the main measurement. From the start ysartglass has used both units throughout. With a childhood based on the imperial system, I can only estimate in imperial but always convert to metric when communicating. My son in the UK, now in his 30's has no idea what an inch is. I struggle with temperatures though, I can never remember what is normal in centigrade (an archaic term used by imperialists for Celsius).
However in old catalogues it is still common to find other types of units in use and these are not always easy to interpret.
I keep next to my monitor a list of conversions, for my site, from imperial fractional inches to millimeters and I always round to the nearest 5mm. Of course accuracy is irrelevant with Monart where an inch of variation can be found in most size codes in practise. Some old catalogues also state that measurements given are nominal or approximate.
-
For myself I'm sticking with the imperial measurement as used by Chance at the time: their plates were listed as 8" or 10" for example, or the Posy Vases are recognised as 4", 5", 7" and 8" in height — as Bernard suggests. But I am also using the metric equivalent as a secondary unit: does add more work, but will help Euro visitors, as well as those British 'youngsters' who were bought up with Metric only :)
As with all things, we do tend to 'visualise' our own terms of reference. I can quickly convert from Imperial to Metric, but cannot appreciate the size until it's converted to 'old money'.
-
I would suggest it is better to adopt a convention that best fits the country of origin of the glass - and the main "audience". Thus, if you are writing about mainland European glass, use metric. If you are writing about English glass, then you will probably need to use both imperial and metric. If you are writing about American glass, you'll surely use imperial. But there's an over-rider! Remember your audience. That must also be taken into consideration. If, for example, you are writing about European glass for an American audience, it would (IMHO) be preferable to use imperial equivalents (and depending on the context, provide metric originals).
If I were to refer to a 15 cm. Rose Garden vase by Brockwitz, the majority of my intended audience would not be able to visualise which of the three sizes of vase I was referring to. Good grief - I'd have trouble myself. But call it a 6" vase and we're home and dry.
I don't think there is one answer, unless it is this; use the best combination to fit the circumstances.
Glen
-
Ultimately I also think the manufacturer's original system should always be taken into consideration.
-
Ultimately I also think the manufacturer's original system should always be taken into consideration.
I do agree with this statement - but with an over-rider - which means for me that although my logic may say one thing, my less-than-logical thought process will over-rule it.
I feel it is imperative to consider one's audience. The example I gave re. my Rose Garden 15 cm. vase above, explains my point. Brockwitz (German) gave all measurements in metric, but if I used those measurements without also giving the dimensions in inches, I'd lose my audience. Crumbs, I wouldn't even understand it myself. :oops:
It's a bit like saying that we should use the original language of the manufacturer - which would not work too well if I found myself having to write about blumenvasen, pflaumenmuster and haardose mit lochdeckel.
Glen
-
Heavens, Australia went metric before I got to school. I believe India went metric in 1960, didn't it?
I literally can't conceptualise a measurement in inches. When I am selling in Australia for Australians, I have to put the metric measure first simply so that people will understand what I am talking about.
Cathy
-
One German catalog from the 1920's has few sizes given. Mostly where they offer two sizes in one design and then the unit is Inches! Interestingly a few items are annotated also in inches with prices in Francs, presumable Swiss as that is where I go this one. A spanish catalog, early 1900's uses millimetres but appears to have been annotated by an Italian hand and uses some other {illegible} units. 19th Century German also use some other units that I have yet to ID.
Ultimately these need to be translated to terms of the audience and both imperial and metric shall be used.
But what about volumes? Glass is described either in named sizes (Claret, Champagne, etc) Ounces or litres or weight. Plus a few in even more obsolete measure. A 1903 US catalogue uses inches/fractions, capacity in ounces, weight in ounces. Plus Pints, Quarts, Gallons and vials are given in drams.
Standard use containers can be sold in Numbers - try finding out which standard was used - there can be several in each trade so you need to also know which trade association they were members of.
-
For me, metric will always be the natural measure, but I do keep to Bernard's convention for any pre-1967 Australian glass.
David,
http://en.wikipedia.org/wiki/Image:SI-metrication-world.png
except it's wrong because Australia went metric in the mid-60s. So I think
that most of the world has gone over to metric units.
Cathy
-
There has been a lot of talk about 'intended audiences'.
Surely if we are talking about the World Wide Web, that potentially means people of all nations. Metric is the dominant system in the world, so it’s the system we should all work around.
Having said that, the best solution (as already mentioned) is to provide measurements in both metric and imperial; although I still say metric should take precedence.
-
This discussion shows exactly why we need to acknowledge the "audience" and offer appropriate measurements (in context) accordingly tailored and "interpreted."
Glen
-
Archaic units:
http://phrontistery.info/unit.html
-
Bringing the topic back to glass, Sowerbys used to export most of their stuff in wooden barrels, which varied in size. The size was described as 25, 35, 40 etc. After plucking up my courage to ask, I discovered that these referred to the number of dozens of pint tumblers which could be packed (with straw) in said barrel.
What would that be in metric?
Sowerbys hadn't made pint tumblers for years!
Adam D.
-
I notice that everyone seems to have ignored my point about careful use of imperial measures conveying accuracy of measurement as well as quantity, something that the metric system has completely lost. The artificial metric system is the one which is archaic and inefficient, whereas the imperial system has evolved to near perfection, or, at least, maximum efficiency. The only two reasons that imperial is thought to be difficult today are that it is not taught at our schools, and that calculators are not designed for it.
Bernard C. 8)
-
Also I notice that everyone seems to have ignored my point about careful use of imperial measures conveying accuracy of measurement as well as quantity, something that the metric system has completely lost.
I sort of agree with what you're saying here, however I don't think it's quite that bad.
I would suggest that a fair number of people, when they read 1.25 cm, would understand it to mean 1 1/4 cm, rather than rounded to the nearest 1/10th of a mm.
If you take 2" - 5cm as an example, then you've got 24 different imperial described distances using 1/12" as the smallest measure, and 20 different metric described distances using 0.25cm as the smallest measure.
OK, you could use 1/16" which would give you more - my point is that metric's not as bad as it first appears for measuring distance.
[having said that, I find myself using C for low temperatures, and F for warm temperatures, so I'd agree that measures can feel more naturally suited to certain tasks]
taylog1
-
To Adam - huge thanks for your input on the barrel measurements at Sowerby's. Fascinating information. I don't know if Fenton gave their barrels specific size references, but I do know what they were able to pack inside their standard barrel.
Any one of these below....
~~~ 6 full water sets
~~~ 4 full punch sets
~~~ 48 regular size compotes
~~~ 72 standard vases
~~~ 90 mixed items (including bowls, compotes, vases, bonbons)
Glen
-
Another aspect of the imperial system that has not been mentioned but is highly relevant is that it was also manipulated politically for financial advantage and from country to country there are variations in how the different units are defined. One that is dangerous in the antiques trade are the unscrupluous who would give rare metal weights in avoirdpois when the tradition was troy weight. I always carried spring balances in both systems so that I could prove the case on those early morning stalls at Bermondsey.
-
I was introduced the metric system in high school as a novelty. In college, it was used some some science classes.
But I still think in Imperial measurements. When posters here use metric measurements, I just skim past them because they mean nothing tome. If I am really interested in the item, I have to do a conversion since I just do not think in metric.
I am involved in international trade and almost all goods imported into the US are dual labeled.
I have a 13 y/o daughter and I know that while she has been taught metric in school, it is not the primary system used and she also thinks in inches, yards, Farenheit and gallons.
If you are marketing glass to the US remember that the baby boomers are the group with the highest buying power at this time in the antique/collectibles market and I can almost guarantee that few think in metric.
JMHO 8)
-
Connie, I agree with you on every point you make.
As an observation only, I also offer the following, out of interest:
Some USA glass auctions (based on several major auction houses for glass, personally known to me) give measurements in inches and fractions thus - eg. 6 5/8" No metric equivalent given.
Christie's in London and New York give measurements in inches and fractions first (as example above), followed by metric equivalent in parenthesis. Christie's in Amsterdam only give metric.
One major UK auction house (ceramics and glass) I came across gave the measurements in inches only - but "decimalised" the fraction eg. 4.75"
Glen
-
Money is almost always counted in units of ten, so why do people find it difficult to understand units of measurement that follow the same principal?
-
Monetary units, now THEY are the bane of researchers! Not only do you need to determine what currency is being used (not always obvious) but to try and get that original price into an understandable 'modern' coomparison. This is best achieved, once the currency is known, by comparing to the average incomes in the country of the currency. This information is about the hardest to come by and only a few examples exist on-line.
UK is as good an example as any with £.s.d. being broken down historically by guinea (£1.05) 20 shillings 240 pennies, 480 half-pennies, 960 farthings, and 1,920 Qu's. Then of course there were third penny coins, groats, (4d) pieces of eight (Spanish currency origin), florins, crowns, half-crowns and slang - tanner, pony, bob, monkey etcetera.
Even more confusing is that the value of a coin was originally based om metal content so the value of a Guinea (Gold coin) was a variable. Fortunately most of glass research is in standardised currency forms.
The tendency in the past to sell glass wholesale by weight was very sensible as it was weight that determined the cost of transport. And of course Adam's example based on volume - which to a certain extent equated to weight. The use of volumetric weight rather than weight or volume alone is still commonly used in pricing transport.
-
The tendency in the past to sell glass wholesale by weight was very sensible as it was weight that determined the cost of transport.
True from a British perspective - it had more to do with the excise on glass which was in place from 1750 to 1850. As far as I know elsewhere (Bohemia, Germany, France) glasses were sold by the dozen.
-
I think imperial was originally based on a human scale, whereas metric is a scientific scale and is therefore more accurate. Personally, I find imperial is an easier measurement to visualise (but I realise that may simply be due to my age :oops: :roll: )
However, the problems with the Hubble telescope shows the importance of being very precise about exactly which scale is being used, and giving both measurements is a useful way round this. Personally, I wouldn't think it mattered which was put first, although the one used by the maker would seem logical.
-
I agree with all the points of view stated :!:
My first job after leaving the British education system was in the Actuarial Valuation section of a Group Pensions department within an Insurance company. All my work on monetary units was carried out in decimals. That was long before that fateful decimal-day in Feb '71 (I think that was the year) when the UK offically started to count money in units of ten instead of 1/240 of a pound. So, I was happy in the knowledge that, for example, in the "old money", 4 pounds 16 shillings and 10 pence was simply £4.84 or £4.84166 (recurring) for greater accuracy.
But a measure such as 2 1/8 inches, expressed as a metric equivalent, was meaningless to me - becuase, as others have said, my visualisation of distance (and volume) was based on the UK imperial units.
I think it would have been better to have started to count distance and volume in units of ten at the same time as the change for monetary units. At least, most folk would only have needed to be confused once.
Anyway, for more practical purposes relevant to this discussion, I believe that metric measures should be a standard for all eBay (and other online) sales of Paperweights. In may not be so important for general glassware, but the size of a paperweight is crucial to many collectors and even a small difference of just 1/8 of an inch (0.28 cm) in the diameter is very noticeable. When seeing only an image and having a brief general description including "diameter approx 2 1/2 inch", it is easy to imagine a size that is greater than the actual. This was true for one weight that I bought off eBay. It was the "approx 2 1/2 inch" size that I neglected to have confirmed. When I received it, it looked smaller than I expected. The actual diameter is a shade under 2 3/8 inch and it is not surprising that the seller rounded up to the nearest 1/4 inch. Had the diameter been stated as 6.0 cm (or perhaps 60 mm), I could have easily checked that against actual weights for a proper size appreciation.
So, if only for the paperweight problem, I would prefer that all imperial measures have the metric equivalent included, at least as an extra, but preferably as the main measure - and this must be a taken measure, not a derived one!
I agree with Glen that the audience is always a major consideration, regardless of convention. I may be giving a talk on paperweights in the future to a group of (older) ladies - and size may be important to them. If they are only "metric ladies", I will use metric, otherwise I will use (or include) imperial.
However, in my web pages, I have used both metric and imperial and I have not always included both. :!: I think I need to make some updates, but whether that wil be to metric only or a mix of both, is somethig I have not decided.
-
On a slight diversion from the topic of glass, the Imperial system is still being used in two areas.
In printing the term 'dpi' (dots per inch) is still prevelant – whether for the rest of the world, I have no idea.
Television and monitor screens (back to glass!) around the world can still be found using the old imperial 'inch' as a term of reference. Admittedly, centimetres are becoming more widely used nowadays. I seem toermember the Germans were using 'ca' as the unit: a 17-inch monitor was referred to as 17-ca, I believe. Perhaps Pamela or Ivo can enlighten me?
-
I seem to remember the Germans were using 'ca' as the unit: a 17-inch monitor was referred to as 17-ca, I believe. Perhaps Pamela or Ivo can enlighten me?
Strictly centimeters here. Some uninformed monitor makers seem to think that "37""or "17"" convey a meaning to us. It does not. Nobody here (or in Germany or anywhere else in Europe) has a clue about inches - so TV shops are full of confusion. Obviously most people know they should multiply by 2.5 to get real figures, but few will have a double concept or take the trouble to convert the figure. Same thing goes for Fahrenheit or a double complex one like MPG. It means precisely nothing to us. Nothing@all.