Probably the experiment published in Machinist's Workshop 20:2 April/May 2007 and followed up on by Sterkel Summary of penetrating-oil test (pdf)
A description of the test. "In case you're wondering, he made a series of shafts and sleeves and corroded them in a salt bath solution. Then the load needed to break the shafts free was tested using a Baldwin compressometer set on 1200-pound scale to determine the load required on the 6 identical setups."