Tony Ferguson on sat 12 jul 08
I recall the were called galena dusters. They would take burlap type sacks full of lead dust and shake them over the work dry glazing the ware. I wonder what their life expectancy was?
I am confused as to "if you father didn't have children neither will you." Well, if he didn't have children, where did "you" come from? 8-).
As to evaporation cooling--this makes me wonder about the filtration properties of clay. I remade a similar tea pot out of earthen ware and did a higher bisque based on a Spanish tea pot (that had broke) that due to the properties of the clay (I would think most clays would work?) would remove the tannins from the tea--thus through use affecting the flavor of the tea that apparently made it taste better and resulted in a healthier tea? I would like to know if there is any research on this? Makes sense to me from what I know about clay and recently Chinese tea pots and their history with tea.
Tony Ferguson
Tony Ferguson
315 N. Lake Ave. Apt 312
Duluth, MN 55806
...where the sky meets the lake...
Artist, Educator, Photographer, Film Maker, Web Meister
fergyart@yahoo.com
(218) 727-6339
http://www.tonyferguson.net
pdp1@EARTHLINK.NET on sat 12 jul 08
Hi Tony,
Below...amid...
----- Original Message -----
From: "Tony Ferguson"
>I recall the were called galena dusters. They would take burlap type sacks
>full of lead dust and shake them over the work dry glazing the ware. I
>wonder what their life expectancy was?
'Their' - meaning the 'Burlap Sacks'? or the people using them?
Their 'Life expectancy' ( in either event ) was probably about the same as
an average North American's is today...or, a little better.
Too -
"Galena deposits often contain significant amounts of silver as included
silver sulfide mineral phases or as limited solid solution within the galena
structure. These argentiferous galenas have long been the most important ore
of silver in mining. In addition zinc, cadmium, antimony, arsenic and
bismuth also occur in variable amounts in lead ores. "
- from http://en.wikipedia.org/wiki/Galena
Being immediately down Wind of the Kilns when they were firing, would be
probably of graver concern than being an operative applying the powdered
Ores to the damp Wares...since for one thing, a lot of the lighter Metals
would 'boil' out into Gasses, happy to condense in the cool Air and drift
for a long ways before settling to the ground...
Gardens for Vegetables in these zones would have been potentially worrysome
I think...also...as would any shallow Wells fed by Rains leaching the
Soils...
The more arid the clime, the more the operatives applying the 'dusts' would
have suffered for the particles being airborne longer...or, the more humid
the clime, the lesser degree of hazard...
> I am confused as to "if you father didn't have children neither will you."
> Well, if he didn't have children, where did "you" come from? 8-).
'Virgin Birth'
With applied Science, or a regular 'Turkey Baster' out of the Kitchen
clutter-drawer, it shall become commonplace.
'Aliens' are also understood to 'fiddle' in these matters, 'harvesting' or
not, as they please...
Then again too, it is usually the 'Mothers' who 'have' Children, and not the
'Fathers'...
Possibly it is the term 'have' which is creating the ambiguity here...
> As to evaporation cooling--this makes me wonder about the filtration
> properties of clay. I remade a similar tea pot out of earthen ware and
> did a higher bisque based on a Spanish tea pot (that had broke) that due
> to the properties of the clay (I would think most clays would work?) would
> remove the tannins from the tea--thus through use affecting the flavor of
> the tea that apparently made it taste better and resulted in a healthier
> tea? I would like to know if there is any research on this? Makes sense
> to me from what I know about clay and recently Chinese tea pots and their
> history with tea.
>
> Tony Ferguson
I don't know...I could not quite follow your paragraph there.
But certainly, a Tea Pot would not do well to be too porous or 'cooling' by
evaporation, unless one wanted Tea which quickly cools in-the-Pot.
Far as I recall, the matter of encouraging the best effects for the Tea, is
more one of allowing a Tea Pot to 'Season', and, not to ever 'scrub' it
clean of stains, and, to use it often enough, so it in fact never dries
out...so it needs to in-effect, remain moist or wet inside,
always...continuously, for ever...and to only use Water which is cooled just
a little from the temperature of Boiling, or depending on one's Altitude
anyway, but regardless, Water which is maybe 195 Degrees or so, and not a
full fledged "212" of the Farenheit way-of-faith.
No Glazed or bare vitrified Clay Body is going to remove 'Tannins' from the
Tea it is holding, so far as I know...nor would even if the Tea were forced
through a porous Clay Body in an effort to strain it...unless possibly, the
aperatures of the Clay Body's porousity were so small as to only allow,
in-effect, the 'Vapor' of Water to pass at extreme liesure, in which case,
any other soluables would tend to be held back I think...and only condensed
'Water' would be on the other 'side'.
Best wishes...
Phil
l v
> Tony Ferguson
> 315 N. Lake Ave. Apt 312
> Duluth, MN 55806
> ...where the sky meets the lake...
Wyndham Dennison on sat 12 jul 08
>
> But I do recall reports that many of the aristocracy of the Roman
> Empire fell victims to Lead poisoning after drinking and eating from
> Galena Glazed pots.
Ivor, they also used pure lead(metal) vessels and wine stored or used in
lead does cause mental problems like Nero burning Rome and the old
saying if your father didn't have children, chances are you won't either.
On a slightly different track, I noticed in an earlier CM pictures of
earthen ware water cooling jugs in the far east that cooled by
evaporation with beautiful green alge/moss growing on the side of the
vessels. Sometimes if we are super clean our bodies lose the immune
system to battle normal bacteria and we can fall prey to modest attacks
that our bodies would normally resist. BTW our clay plasticity comes
somewhat from nasty, stinky bacteria that lives and grows where we play.
If you want to really see some stuff, put a sample of the throwing water
under a microscope. Later Wyndham
Ivor and Olive Lewis on sun 13 jul 08
Dear Wyndham Dennison ,
I believe over the ages people have suffered from lead poisoning when
they used Pewter, originally a lead alloy. The substitute is called
Britannia Metal, an alloy of Tin, Antimony and Copper.
The places with natural clay, the banks of streams where I played as a
child, had the aroma of good earth. We used to drink the water that
flowed past the clay. Sweet and refreshing without any foul odour.
I do not believe the story that clay plasticity is due to bacteria, in
spite of the descriptions in the popular ceramic literature, in spite
of information stored in Clayart Archives, or information passed from
potter to apprentice or teacher to student. Clay is plastic for the
same reasons that other materials, including metals can exhibit
plasticity.
Perhaps residues that accumulate in throwing slurry smell because they
are loaded with discarded, decaying cells from our hands and the
bacterial flora that inhabits our skin.
Green algal growth in water discharges pure Oxygen into the liquid.
Anaerobic bacteria, those mentioned by Edouard as being "pathogens"
tend to die in such an environment.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Kim Hohlmayer on tue 15 jul 08
Hi Wyndham,
In Egypt even today one will see these "water coolers" up on stands in peoples yards as the prime source of cool drinking water. Many people still wash clothes and dishes in the Nile too though the government tries very hard to discourage this practice.
When I traveled there in the 1990's I never once got sick. However I did get a nasty case of food poisoning (egg burrito) on the KLM jet on the way over there!!!!! Then the last two days there I came down with a horrible case of upper respiratory flu I had picked up in my doctor's waiting room a week before I left. I had stopped in to pick up some medicine to insure I wouldn't be sick on the trip but picked up the flu bug instead from the coughing and sneezing patients around me. So much for the illusion of a super clean, germ-free American society. ;^)
--- On Sat, 7/12/08, Wyndham Dennison wrote:
> From: Wyndham Dennison
> Subject: Roman lead glazed ware
> To: CLAYART@LSV.CERAMICS.ORG
> Date: Saturday, July 12, 2008, 9:20 AM
> >
> > But I do recall reports that many of the aristocracy
> of the Roman
> > Empire fell victims to Lead poisoning after drinking
> and eating from
> > Galena Glazed pots.
>
> Ivor, they also used pure lead(metal) vessels and wine
> stored or used in
> lead does cause mental problems like Nero burning Rome and
> the old
> saying if your father didn't have children, chances are
> you won't either.
> On a slightly different track, I noticed in an earlier CM
> pictures of
> earthen ware water cooling jugs in the far east that cooled
> by
> evaporation with beautiful green alge/moss growing on the
> side of the
> vessels. Sometimes if we are super clean our bodies lose
> the immune
> system to battle normal bacteria and we can fall prey to
> modest attacks
> that our bodies would normally resist. BTW our clay
> plasticity comes
> somewhat from nasty, stinky bacteria that lives and grows
> where we play.
> If you want to really see some stuff, put a sample of the
> throwing water
> under a microscope. Later Wyndham
Kim Hohlmayer on tue 15 jul 08
Hi Tony,
My father didn't have children and neither did I. I am adopted and so is my son. ;^) --Kim H.
--- On Sat, 7/12/08, Tony Ferguson wrote:
> From: Tony Ferguson
> Subject: Re: Roman lead glazed ware
> To: CLAYART@LSV.CERAMICS.ORG
> Date: Saturday, July 12, 2008, 3:07 PM
> I recall the were called galena dusters. They would take
> burlap type sacks full of lead dust and shake them over the
> work dry glazing the ware. I wonder what their life
> expectancy was?
>
> I am confused as to "if you father didn't have
> children neither will you." Well, if he didn't
> have children, where did "you" come from? 8-).
>
> As to evaporation cooling--this makes me wonder about the
> filtration properties of clay. I remade a similar tea pot
> out of earthen ware and did a higher bisque based on a
> Spanish tea pot (that had broke) that due to the properties
> of the clay (I would think most clays would work?) would
> remove the tannins from the tea--thus through use affecting
> the flavor of the tea that apparently made it taste better
> and resulted in a healthier tea? I would like to know if
> there is any research on this? Makes sense to me from what
> I know about clay and recently Chinese tea pots and their
> history with tea.
>
> Tony Ferguson
>
>
>
> Tony Ferguson
> 315 N. Lake Ave. Apt 312
> Duluth, MN 55806
> ...where the sky meets the lake...
>
> Artist, Educator, Photographer, Film Maker, Web Meister
> fergyart@yahoo.com
> (218) 727-6339
> http://www.tonyferguson.net
Joseph Herbert on wed 16 jul 08
Phil wrote: Being immediately down Wind of the Kilns when they were firing,
would be probably of graver concern than being an operative applying the
powdered Ores to the damp Wares...since for one thing, a lot of the lighter
Metals would 'boil' out into Gasses, happy to condense in the cool Air and
drift for a long ways before settling to the ground.
This is not totally true. The amount of material leaving the kiln depends
not only on the vaporization temperature but also on the temperature of
surrounding kiln parts. IF the stack of a fuel kiln were long enough to
have cool areas, a lot of metal will condense there. In a normal electric
kiln, the lead does vaporize and also condenses on any part cooler than the
condensation temperature. The edges of the door, for example would have
lead oxide deposits in the cooler areas. An example of a different metal in
a different industry is arsenic. Present in parts per million in coal,
arsenic concentrates on furnace parts cooler than about 1500 degrees. Since
million of pounds of coal pass through a power plant furnace, any retention
builds up to considerable concentrations on the water tubes, super heater
tubes, and fly ash accumulations. Some plants have to dispose of fly ash as
hazardous waste.
A different concern with galena is sulfur dioxide. As seen in Ducktown,
Tn., sulfur emissions from a smelter, and when galena is a glaze material,
the kiln is a smelter, devastated the countryside. Very much a moonscape,
devoid of plants. Perhaps from metal deposits, but certainly from acid
rain.
As far as breathing lead sulfide dust, probably not a good idea. Lead
sulfide is pretty insoluble and would require some additional activity to
become poisonous. A decade of pot dusting would certainly do something.
However, barium sulfide is also very insoluble and ingested by people daily.
Not every day, of course.
Heavy metals are such fun! I just like them better as colorants.
Joe
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6:03 PM
John Hesselberth on thu 17 jul 08
> Phil wrote: Being immediately down Wind of the Kilns when they were
> firing,
> would be probably of graver concern than being an operative
> applying the
> powdered Ores to the damp Wares..
Hi Phil,
What follows is from England, not the Roman Empire, but here is a
very short quote from "Researches in Leadless Glazes" written by
William J. Furnival and published in 1898. Before he goes into his
research and the information he has gathered from others, he takes 20
+ pages to detail why he is on a quest for leadless glazes.
" Dr. Prendergast mentions 432 cases of lead-poisoning occurring in
the earthenware and china manufacture during the year 1896, of which
382 were from potteries....Mr. Bertram Wilson, in the Hanley Labour
Church report on lead-poisoning, refers to inquests upon the bodies
of two young boys, fourteen and fifteen years old, who had worked in
the dipping house only six and twelve months respectively. Of the 156
cases reported to them, twelve resulted in total blindness, two of
these being paralyzed and insane, three of them died since having
been reported....Fitly does he remark: 'Heavy is the price that
humanity pays for the use of raw lead in the potting industry.'......"
These were reports of folks working in the factories and handling the
glaze materials. I suppose people downstream of the kilns could have
suffered also; however it is clear that handling the glazes of the
day was really bad news.
That book is one of the prizes I found on the used book market when I
started doing the research for Mastering Cone 6 Glazes. It is
fascinating reading--all 120 pages of it. Among other things Furnival
expresses frustration regarding those who had made progress in
leadless glazes and would not make their work available to others. He
even names names.
Regards,
John
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Kim Hohlmayer on fri 18 jul 08
John,
Thank you. It makes you wonder why still up to this very decade companies selling commercial hobby glazes still used lead glazes. I helped clean out the supply closets of a local art group only to find what might as well have been a toxic waaste dump of old glazes. Had the same experience where someone donated a box of POWERED Amaco leaded glazes to the art dept. of a Christian grade school. Needless to say, the day I came to teach there and found those I got the out of there. Then one has to wait for a toxic waste clean-up day in the county to get rid of that stuff. --Kim H.
--- On Thu, 7/17/08, John Hesselberth wrote:
> From: John Hesselberth
> Subject: Re: Roman lead glazed ware
> To: CLAYART@LSV.CERAMICS.ORG
> Date: Thursday, July 17, 2008, 1:53 PM
> > Phil wrote: Being immediately down Wind of the Kilns
> when they were
> > firing,
> > would be probably of graver concern than being an
> operative
> > applying the
> > powdered Ores to the damp Wares..
>
> Hi Phil,
>
> What follows is from England, not the Roman Empire, but
> here is a
> very short quote from "Researches in Leadless
> Glazes" written by
> William J. Furnival and published in 1898. Before he goes
> into his
> research and the information he has gathered from others,
> he takes 20
> + pages to detail why he is on a quest for leadless glazes.
>
> " Dr. Prendergast mentions 432 cases of lead-poisoning
> occurring in
> the earthenware and china manufacture during the year 1896,
> of which
> 382 were from potteries....Mr. Bertram Wilson, in the
> Hanley Labour
> Church report on lead-poisoning, refers to inquests upon
> the bodies
> of two young boys, fourteen and fifteen years old, who had
> worked in
> the dipping house only six and twelve months respectively.
> Of the 156
> cases reported to them, twelve resulted in total blindness,
> two of
> these being paralyzed and insane, three of them died since
> having
> been reported....Fitly does he remark: 'Heavy is the
> price that
> humanity pays for the use of raw lead in the potting
> industry.'......"
>
> These were reports of folks working in the factories and
> handling the
> glaze materials. I suppose people downstream of the kilns
> could have
> suffered also; however it is clear that handling the glazes
> of the
> day was really bad news.
>
> That book is one of the prizes I found on the used book
> market when I
> started doing the research for Mastering Cone 6 Glazes. It
> is
> fascinating reading--all 120 pages of it. Among other
> things Furnival
> expresses frustration regarding those who had made progress
> in
> leadless glazes and would not make their work available to
> others. He
> even names names.
>
> Regards,
>
> John
>
> John Hesselberth
> http://www.frogpondpottery.com
> http://www.masteringglazes.com
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