The pieces at each end of the sole are of cast-brass, instead of sheet-copper, with soft-solder joints, which are very apt to give way.    From Wordnik.com.  [Fire Prevention and Fire Extinction] Reference

Page 156 on the desirability of the fruit of the tree of knowledge that it is no wonder that some are at a loss to tell the real apple from the soft-solder affair tinted over with the russet hues of insincere representations.    From Wordnik.com.  [Buried Alive (Behind Prison Walls) For a Quarter of a Century. Life of William Walker] Reference