Figure 5

Raman spectra of the A4 wall of the peristyle. (a) Niter (715, 1050, 1342 and 1359 cm⁻¹) together with aphthitalite (452, 621, 992, 1083 and 1204 cm⁻¹). (b) Nitratine (1067 cm⁻¹), calcite (157, 285, 713 and 1085 cm⁻¹) and the complex nitrate signature (1053 cm⁻¹).