Regarding the odour. It seems to have something to do with the clay lining of the tanning pit which often exhibits as a yellowish or white substance on the inside of the pit darkening to normal London Clay brown/grey/blue on the outer side.
My own guess ('O' level Chemistry only I'm afraid) is that the yellowing of the clay is caused by the presence of selenite (Calcium Sulphate) in the London Clay and perhaps other sulpharous compounds leaching from the 'tanning formula' and somehow being 'fixed' through contact with the clay. Does that sound feasible and could that account for the longevity of the odour?
r ide perhaps leaching from the
some formsome sulining am sure that you are correct r
"White, Bill" <[log in to unmask]> wrote:
Kevin, I am happy for you to disagree with me; this is the way
that mistakes are corrected, misapprehensions are exposed and
all of us learn from the process. However, this time we are not
exactly disagreeing. Ian Barefoot in his message of 24th said
that PCA had excavated pits lined with horn cores "hypothesised
as being connected with the tanning process". I added that such
pits were not unusual in London nor necessarily primarily for
tanning. You have added further examples.
As for genuine tanning pits of the clay-lined variety, you mention
a "distinctive lingering odour". To resume the earlier theme of
body fluids spontaneously expelled on battlefields, any idea what
(chemically) causes the odour? The main organic solute in human
urine is urea, which rapidly decomposes under the influence of ambient
bacteria into carbon dioxide (possibly fixed as carbonate salts) and
ammonia. The latter certainly has a distinctive odour but cannot
"linger" for hundreds of years. Any thoughts?
Curator, Centre for Human Bioarchaeology
Museum of London
150 London Wall
London. EC2Y 5HN
Tel: +44 (0) 20 7814 5649
Fax: 020 7600 1058
Email: [log in to unmask]
Glamour, grandeur, sleaze, disease - discover a great city in the making in the new Medieval London gallery
Free exhibition - SATIRICAL LONDON, 300 years of irreverent images - until 3 September 2006
Register for regular Museum updates with [log in to unmask] Message-----
From: British archaeology discussion list
[mailto:[log in to unmask]]On Behalf Of kevin wooldridge
Sent: 27 July 2006 15:39
To: [log in to unmask]
Subject: Re: [BRITARCH] Stone-lined tanning pits ....or not!!
Sorry to disgree with my friend Bill White, but in all my years in archaeology I have never come across a tanning pit lined with horncores (and I have seen and excavated numerous tanning pits in London, particularly in the Bermondsey area of Southwark since 1982).
The purpose of tanning pits requires that they must be as watertight as possible to retain as much of the 'tanning formula', over a considerable period of time (we are talking months and years here rather than days and weeks). I understand that the 'tanning formula', consisiting of a mixture of oak bark and urine would have been a relatively costly part of the process and every effort would have been made to conserve it. Horncores would not achieve that end as they are porous and do not form a watertight seal. Most London tanning pits are clay lined and it is that (and the distictinctive lingering aroma) that makes them fairly easy to identify.
The most likely reasons for using horncores to line medieval and post-medieval cess pits (as opposed to tanning pits) is because they happen to be available, are very durable and, once the outer horn has been stripped, of very little commercial value. The porosity of the cores and the non-watertight nature of the cess pit lining allows the liquid part of the cess to drain away, leaving 'solid waste' which can be shovelled out and away. (Not entirely unlike the nature of the settling tanks on a modern day sewage farm).
J C Blyth wrote:
What would have been the particular advantage of using horncores to line
pits? For what purpose would these pits have been constructed and what date?
My curiosity has been piqued!
Copy addresses and emails from any email account to Yahoo! Mail - quick, easy and free. Do it now...
Try the all-new Yahoo! Mail . "The New Version is radically easier to use" – The Wall Street Journal