Within the Mary Rose samples, several different environments are represented. The differences between the untreated Mary Rose sample that received no conservation, and the samples that were treated with PEG can be used to understand the ability of PEG to chemically and physically preserve the wood. The sample without PEG has undergone chemical and physical degradation during the 30 years following retrieval from the sea floor, and hence has different properties. PEG treatment is also dependent on the distance from the surface of the artifact: PEG 200 will go about 4-5 cm into the wood, PEG 2000 goes about 1-2 cm. The edge subsample will have received more PEG2000, whereas the core sample will have received only PEG 200 if any . These effects have been confirmed using various diagnostic techniques . Within the treated sample, the edge subsample from the outside of the hull would have been exposed to seawater and burial after sinking, while the core subsample deeper within the beam was less directly exposed to the effects of continuously refreshed deep seawater. Thus, the Mary Rose sample set represents three environments: material which has been exposed to the atmosphere for 30 years with no protection and material which has been preserved with PEG, which can be subdivided into material which was exposed to seawater over 400 years (the edge) and material which has been more protected by its position in the interior of the beam (the core).