Three samples of steel from museum collections were submitted to a metallographic examination. These comprise a piece from the last blister steel production in England (1951), a historic specimen made specially in Sheffield in 1877 for the famous Dr. Percy to elucidate his theory on the production of blisters in blister steel, and the only known sample of puddled steel still in existence, collected by Dr. Percy in 1859 from the Ebbw Vale works. The experimental sample was produced by remelting wrought iron in a crucible to remove the slag and subsequently carburizing in the cementation furnace, no blisters appearing in this particular case. The micro cleanness of this sample is remarkably good (so much so that it is hoped in the near future to check a number of samples of crucible steel from the Percy collection to determine whether this is typical). The other two samples did, as was expected, contain a fair proportion of entrapped slag and the nature of this was examined. -- AATA