Stratigraphy of the spheres
The succeeding layers that make up the globes’ spheres were studied by Karin Wyss and Drs Stefan Zumbühl, Nadim Scherrer and Margaux Genton at the Swiss Institute for Art Research (SIK|ISEA) in Zurich using IRTF, DTMS and SEM technology. The SIK|ISEA report (2015: 30) provided details on the spheres’ constituent materials from the inside towards the outside, numbering the layers 0 to 9.
| 9. | Varnish (recent and ancient coats analysed together) Natural resin : dammar or mastic, saturated fatty acids and dicarboxylic acid; fat (possibly oil). |
| 8. | Brown-black printing ink Vermillion, burnt umber, kaolinite, quartz and traces of arsenic. |
| 7. | Paper gores The paper was not analysed specifically (see page entitled Surfaces and pigments). |
| 6. | Layer of glue between preparatory layer and paper Starch glue with proteic inclusions. This layer cannot be seen in all the stratigraphic layers but is revealed by SEM. |
| 5. | White preparatory layers under paper Calcium carbonate, shell fragments, proteic binder (probably skin or bone glue) and traces of fat (oil). |
| 4. | Pinkish fibrous layer Cellulose (from paper, cardboard, wood or textile fibres), starch, calcium carbonate, proteins or oils ? It is difficult to determine the exact composition as the spectra of the various materials overlap. |
| 3. | White preparatory layer This layer was not analysed specifically but it is probably made up of a chalk-paste mixture like the next preparatory layer. |
| 2. | Piece of printed paper This was glimpsed at about this level in a nick. |
| 1. | Grey fibrous layer This layer was not analysed specifically; it is made up of grey fibres, probably cardboard and/or papier-mâché. |
| 0. | Dark brown layer First visible layer, not analysed specifically, made of tiny wood chips. It could only be seen in a nick and in the sample for the C14 test. |
Find out more
- Les globes de Mercator de l’Université de Lausanne. Observations matérielles. Constat d’état. Rapport de conservation-restauration: The Mercator globes of the University of Lausanne. Material observations. Condition report. Report on conservation-restoration, Workshop and laboratory of the Swiss Institute for Art Research SIK|ISEA, Ref. No.0 0002: 01/02, October 2015, Margaux Genton, Zurich.
- Composition of the spheres : this page presents the composition of the terrestrial globe in detail, from the inside towards the outside, as revealed by stratigraphic cross-sections and an analysis of the constituent materials.