Leaded Lettering as an Indicator of Gravestone Weathering

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The amount of material removed from gravestones by weathering is often measured using a reference called the Lead Lettering Index (LLI). This index assumes that the lead lettering inserted into gravestones was originally polished flush to the surface. Over time the stone has been eroded and left the lead lettering standing proud. It is assumed that the lettering has not been eroded to any significant degree itself.

Assuming a relatively uniform rate of erosion across the whole gravestone, measuring the height difference between the lead lettering and the stone surface indicates how much material has been removed since the gravestone was exposed. Repeated measurements across the gravestone should then provide a representative sample of height change. If the same letters are selected, for example the '1' in the date or the 'I' in died, then comparisons are possible between gravestones keeping the letter location approximately constant. The examples given show lead letters of different dates; the older the date, the greater the difference in height between the marble and the raised letter.

As the stone erodes, however, the lettering itself can become loose and begin to peel off. Often the lettering is attached to the gravestone by small lead pegs and these become loose. The lead lettering begins to curl away from the surface and eventually drops out. The impression of the lettering, complete with peg holes, is often visible in old gravestones. This means that there is a limit to the age of gravestones that can be measured using this method. Once peeling of lettering begins the method becomes difficult to apply with any consistency.

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Above: marble gravestone (age unknown). Lead letters were originally attached to the stone by means of pegs. Extensive weathering of the marble has removed the surface of the rock and caused the letters to fall out. Only a few remain, raised above the surface of the stone. The pegs are now visible. 

LEAD LETTERING IN THE CITY OF LONDON CEMETERY

The St. Antholin monument - Marble
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The Corby, Crick and Auvache memorial - Marble

This headstone gives an excellent example of how lead lettering can be used to estimate the rate of weathering of marble. There are five inscriptions of dates ranging from 1933 to 1999. It is clear to see that the most recent lettering is flush with the surface of the stone, but that they are progressively relatively raised as the inscriptions become older towards the top.

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Unknown grave - Limestone

On this Portland limestone grave, the letters appear to have been engraved first, with lead pressed into the carving. Much of the lead has now fallen out, exposing the limestone beneath to the elements. The lettering is then no longer protected, and will start to weather and become indistinct.

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REFERENCES

Gore, P.J.W., 1995, Weathering, Georgia Perimeter College , Clarkston, GA 

Inkpen, R., 2001, Gravestone Weathering, Department of Geography, University of Portsmouth (including classification of gravestone weathering table) http://www.envf.port.ac.uk/geo/inkpenr/graveweb/gravestone.htm

Meierding, T.C., 1993. Inscription legibility method for estimating rock weathering, Geomorphology, 6, 273-286.