Glass Message Board
Glass Identification - Post here for all ID requests => Glass Paperweights => Topic started by: hunter-g on May 01, 2013, 02:22:00 AM
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I'm wondering where opinion falls with this one, which was attributed to Bacchus - and according to the previous owner, originally carried that attribution at the time he purchased it around 13 years ago.
Dimensions are 3 15/16" d x 2" h, and the dome rises very tightly almost straight up from the base, (making it difficult to pick up easily from a flat surface & weighing half a ton - well, actually ~1 kilo). Slightly concave base w/ neatly snapped pontil (not firepolished), and very gentle seam where main gather joins the ground/setup. Wear on rim is even and approx 3/32". Also see how center cane stands above others (profile). Curious. Thanks to all...
/ h-g
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Hi. This does not look like Bacchus to me - I am fairly sure they are Richardson canes. If you are able to measure the density I think it will fall within the Richardson range, rather than the Bacchus range. The shape suggests that it has been quite heavily repolished - it may have been a bottle that suffered severe damage - such pieces often end up as rather unusual shaped paperweights.
Alan
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:) What does "OE" stand for?
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Hi Sue.
OE = Old English.
Alan
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Cider? ;)
Thanks, Alan. :)
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Hi, Alan, et al & thanks for the input.
It hadn't occurred to me that it may have been re-shaped. Is there any way of "reading" the dome and striae for signs? In following your comment, I do notice a few (broad) irregularities in the surface which could indicate innaccuracies in the finishing, but I'm inclined to feel (quite literally, if you'll pardon the pun) that they're consistent with the original marvering and shaping since they are extremely subtle and appropriate to the size and proportions of the piece. Optically, it also seems as close to perfect as one could expect, and the striae seem essentially concentric (and diminishing) right up to the dome. There are also a couple of small / shallow dings at about 45 degrees and light scratches which could be new or old, but don't hint at being remnants of older, deeper damage.
So to your next point: Is there a relatively straightforward method for determining SG that could be practical (and accurate) for a home- or self-test? I've never attempted it, but think I understand the principle and would be willing to give it a go... with a little guidance &/or encouragement. :)
btw/ Fluorescence under a SW handheld (UVP Mini UVG-4 254nm) is virtually identical to Antique Baccarat on average, and if anything a bit Less Blue / leaning slightly toward Green, as do three other likely Richardsons pieces I have, and just compared against. (Always makes my eyes hurt no matter how I try to limit my exposure, so the observations are brief.) Hope that's helpful.
Once again, thanks, and no doubt, I'm here to learn!
Bruce / h-g
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Hi Bruce
You can measure the SG at home without too much difficulty. What you need to be able to do is measure the weight of the paperweight in air and also when submerged in water (which provides a means of calculating the volume).
The difficulty is constructing a way of doing this that allows you to keep the measuring process and set-up identical when you make the two measurements. I do it by suspending the paperweight on the end of a hinged arm which rests on a knife edge on a set of electronic kitchen scales. This allows me to measure the weight in air, then to surround the paperweight with a jug of water, brought up from below, and to get a measurement of the weight in water without having moved any of the measuring equipment. See images below.
These are not 'real' measurements of the actual weights, because the hinged arm magnifies the figure, but that does not matter provided the set-up is identical for the two reading. If the weight measured in air is Wa, and the weight measured in water Ww, then the Specific Gravity (SG) is calculated as:
SG = Wa / Wa - Ww
Those who recall their basic physics will see that it does not matter what 'units' you make your measurements in, as long as they are the same for both readings, as the 'units' cancel out. There is a minor issue about temperature, as glass and water have different co-efficients of expansion, but if both the paperweight and water are at room temperature you will get a fairly accurate result. You can check the repeatability of your system very easily - if everything is stable, then you ought to be able to get it consistent to 1 part in 250.
Regarding fluorescence, I think it is quite good at telling you if glass has lead in - when you get the blue you have observed - but I think there needs to be a proper objective and rigorous study with professional spectrometry equipment before I will be convinced it can tell you much more. It is very subjective if you just shine a UV lamp on it and report what colour you think you see: we are different people, with different eyes...and we know that eyes vary - eg colour blindness.
Alan
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Hi Bruce
I forgot - here is an image of a Richardson weight I used to own, using a similar blue colour to yours.
The SG of this is 3.13, well within the Richardson range of 3.10 to 3.17. The 20 Bacchus I have measurements for range in SG from 2.96 to 3.10. If you measure a weight at 3.10, then it could be either of those - and also Arculus ( 3.08 to 3.12), and (of course) yet another, unknown factory!
Alan
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Hi, Alan,
In that I don't have a balance-beam scale, I went about it in a slightly different way, but am hoping that it was valid: I determined the volume of the PWT by displacement (All @68 degrees F / 20C) and then went to three different places locally to have it weighed and taking the average, then divided the volume into the weight. The result: 2.9496. (!) Yikes (!) I figure my accuracy was within a half of a percent on the volume at worst - and if anything I would say I erred on the long side in my measurement. If I reduce / correct the volume by 1/2% I come up with 2.9545, so either way, it would seem I'm right at the far low end of the range, which I would guess is more telling than if it were at the higher end? As long as my method was valid, I'm encouraged by the numbers to say the least... :o
As to fluorescence, I know it's very subjective (though I do have a very keen eye for color), but thought anything that might be useful as an observation is data nonetheless, even if it's not entirely possible to quantify it.
One other thing regarding the canework, and in particular the outer row and to a lesser degree the inner one too, have almost transparent white ruffles. They are so delicate you can see through them, and that is one quality I only recall seeing in Bacchus (and Gillinder) weights to the best of my knowledge. Not to be contrarian, but I am again encouraged by this detail as potentially significant.
Needless to say, my optimism rarely goes unpunished, so I remain cautious (knowing that as a pessimist, I'd welcome a pleasant surprise over constant disappointment any day!)
And today was a fun one, I can assure you, no matter where it all ends up! Thanks for the refresher on the technical approach - it has been a while since I've applied anything from my school days with any discipline - and was a nice boost to confidence as I doublechecked my work. Yes, it looks good to me... So....?
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Hi Bruce
I tried the water displacement method for volume, and in the end could not get accurate enough results - but maybe that was my method that was at fault.
Anyway, I have posted below images of four classic Bacchus weights. What I feel is that neither your weight nor my weight have much in common with the style of the canes in these - and the near transparent white ruffles appear in quite a lot of Old English weights, if you search around, so I don't think they are definitive. The canes in your weight have more in common with Richardson - but none of this is conclusive evidence that your weight (or mine) is not Bacchus - and I would love several of my 'uncertain' Old English weights to be Bacchus. However, in my heart, I do not think they are!
It is this sort of uncertainty that makes OE weights fascinating for me.
Alan
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I certainly agree, Alan, that there's very little to suggest anything more than a basic similarity between this and definitive Bacchus canes. I've reviewed everything I can get my hands on, and never yet a direct match. (Same with the PWT Related Sugar Bowl Trinket / Powder Box I posted a few days back). "Unidentified" or Richardsons suits me fine, as there's little doubt it's OE, and I love the rather delicate work. The cyan is probably my favorite color too as far as glass goes. Really quite an electric blue, and very similar to a beautiful tobacco jar I have with the overlay cut to clear. (Different animal, but number one in my cabinet - outside of weights, of course.)
The question of SG seems interesting, and would warrant another go so the accuracy can be guaranteed, though I'm quite confident of my method - I was very careful. I'll forward info if/when I can revisit it. I really appreciate your help and reference photos. And btw/ I have indeed seen a number of Richardsons'-type canes where the white is similarly translucent - I musta had my blinders on earlier :) or selective memory loss. Purely a matter of convenience, either way...
Many thanks,
'til next time,
Bruce / h-g
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Hi Bruce. Accuracy / repeatability is a key aspect of any measurement. And here is a word of caution for anyone making SG measurements: the margin of error depends very much on the scales you use, and whether you work in grams or pounds and ounces. That is because the scales round the measurements to a nearest figure (whether the nearest gram, half ounce, quarter ounce etc).
To illustrate: suppose you have a typical OE paperweight, weighing 660 grams / 1 lb 7 ounces. If it is of lead crystal, and the actual SG is 3.000, then the weight in water will be 440 grams / 15 1/2 ounces.
What results might you get, using typical electronic kitchen scales that measure +/- 1 gram? The answer is between 2.977 and 3.023. Using my cantilever arrangement to magnify the effective weight by about 3 times, I would get a result between 2.992 and 3.008.
For pounds and ounces, the answer is far from encouraging. If the scales measure to the nearest 1/2 ounce, the spread of results will be from 2.765 to 3.286! That is so large as to be of little use. If you can get to the nearest 1/4 ounce, it is not quite so large a spread ( 2.848 to 3.159), but still too large to be of much use in distinguishing makers.
Conclusion - you need to be working in grams, with scales that measure to +/- 1 gram.
Alan
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I determined the volume of the PWT by displacement
The question of SG seems interesting, and would warrant another go so the accuracy can be guaranteed, though I'm quite confident of my method - I was very careful.
I would be interested to know about the actual method used to determine the volume by displacement. Was this done with a scientifically calibrated measuring beaker? Or was it done by measuring the displaced liquid as an overflow from a "full" container? If the latter method was used, how were factors such as liquid surface tension accounted for?
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Good Morning, Alan and Kevin,
I'll describe my process, which was really quite simple. I began with measuring off a quantity of water with a calibrated photographic beaker (CC's / US Fl Oz) and taking a temperature reading since I know temp will affect density. Photography conveniently had me accustomed to working w/ 20 Degrees C / 68F, which is right where I was (and s/b as a "standard" for referencing SG, as I found in several articles online, just to be sure). So, I placed the weight upside down in a small stainless steel pot and proceeded to add the water while keeping track of the quantity just as a matter of course, until the weight was completely submerged. Although this quantity is essentially immaterial, it came out to be 825 cc's. This also allowed the PWT to be at the same temperature as the water after a few minutes rest, since it was very close to begin with (within a degree - ambient air temp).
With a permanent blue marker, I began placing dots down the inside of the pot until I finally touched the surface of the water, at which point the ink immediately flared and created a perfectly level / straight line at the boundary of the water. So as to not disturb this neat little indicator, I tilted the pot with the handle so the water level fell safely away from it then retrieved the weight, ensuring that my fingers wouldn't displace the water near the line, and gently shook of any excess back into the pot as I returned it to level. Other than damp fingers, essentially none lost.
From this point, I simply added water from the calibrated beaker to the pot until the level reached the line, and recorded the amount needed to replace the amount which the Weight had occupied. That volume was 299 cc's.
Not knowing the actual weight of my subject was the next problem. My scale only goes to 600 grams. I phoned my local pharmacy and soon arrived to have them weigh it. No go, since their digital scale only went to a few hundred grams. Same deal w/ 2 local jewellers, but I found 3 shops who advertise wanting to buy gold, and was able to get tenth-of-a gram accuracy from 2 and dwt from the other: (882.2, 881.8 and by conversion 881.78 which averages 881.92 g.) I figured it was important to get at least 3 readings since one never knows how accurate their scales are, ie, trust but verify... and taking the average as a matter of best practice.
Now, simply creating a ratio of the weight in grams over the displacement / volume (also in grams since cc water @ 20C = grams) 881.92 / 299 yields 2.9496. Figuring also that my potential for error in measuring the displaced water was somewhere about a half cc at worst, and knowing that if anything, my reading was higher, not lower (yes, Kevin, due to that pesky surface tension of the water not creating a perfect plane in the graduate), I subtracted 1/2 cc and refigured: 881.92 / 298.5 = 2.9545 SG. And confident that I'm well within a half of a percent of accuracy. The smile grew large as I realized that it was right near the low end of your observed Bacchus SG's, and I'm also accepting that there's a chance that my error may be larger, but as stated above, if anything, my figure for displacement would be high, so reducing it would only increase the SG, and move it more into range... everything else I can be 99.999% sure of.
So, there's my story. Kitchen Science at its best! :) With a little patience and care, I'm sure it's repeatable, and might afford others something to go on, especially if they've got a proper scale to work with. I believe it is about as straightforward as can be, since the objective is to know the volume of the PWT and then compare it to its mass (weight). Empirically measuring the difference in weights in air & water I'm sure works fine too, though somehow to me at least, seems a step removed from simplicity. But if it is a more accurate method, I'd be inclined to stick with it too. Of course, being able to do BOTH tests should only improve the confidence beyond any doubt, since they're taking different paths to the same result.
This is fascinating stuff and nice to dust off the cobwebs for a change! Thanks. Maybe there's still a chance I've got an "unknown Bacchus" after all? Wake me when it's over...
Bruce / h-g
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Hi Bruce.
Your approach would appear to leave relatively little uncertainty in the measurement: an error of 1 cc in volume either way would put the SG in the range 2.935 to 2.955. But Bacchus is not the only possibility in that range - I have measured a few other OE paperweights that had SG in the 2.93 to 2.96 range, such as the two shown below. The first one is a member of the 'OE 1' Group that I have written about, from an unknown maker. The other is very neat, but there is nothing that ties it in to Bacchus.
One has to remember that there were probably 30 or 40 glass factories in and around Birmingham and Stourbridge in the mid to late 19th century that might have made 'Old English' paperweights, and we know very little about the output of most of them.
Alan
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Beautiful weights, Alan! Regardless of who made them. Of course it would be wonderful if any info on those lost factories ever turns up, and gives us a name or two from so many... At least it's nice to know this is likely a relative. Many thanks again to all for your thoughts & help!
B / h-g