Page:The museum, (Jackson, Marget Talbot, 1917).djvu/215

Most objects which come into an archaeological collection, especially if they come directly from the field of excavation, are in need of treatment of some kind before they are ready for exhibition. Bronzes from Egypt are almost all subject to the patina containing chlorine salts that is so harmful, and some process of reduction or impregnation needs to be used before it is safe to put them with other objects. Coins are frequently in very bad condition and need to be reduced by an electrolytic process to bring out inscriptions, etc. All objects of terra cotta and limestone are attacked by salt crystals, and need prolonged treatment before the curator can be sure that they will remain secure. The scope of this little book is too limited to enter into details in regard to these processes. Suffice it to say that they have been worked out scientifically and thoroughly by Professor Rathgen, the official chemist of the Berlin Museums, who has published a little handbook for curators called "The Preservation of Antiquities," to which reference has been made before. While there have been continued experiments since that date, and some processes have been modified by further experience (see Museumskunde, vol. IV, pp. 12, 88; VI, 23; VII, 218; IX, 44; XI, 32 and Rhousopoulos, Museumskunde, vol. VII, 95, translated in Museums