A special core drilling machine was developed to take in situ samples of stone damaged by atmospheric pollution. An additional system was set up to measure the energy consumed by drilling and data was gathered on the cohesion of the sampled material. Below a certain depth, constant and characteristic values were obtained for several buildings where the same stone had been used and the material had been protected from rainfall. The superficial layers showed significant changes in cohesion. The sulfur-carbon distribution was compared to the cohesion measurements and two distinct types of superficial alteration could be determined. First results are encouraging. This system, once improved, can contribute important data to the study of superficial stone alteration. -- AATA