Ewing &: Rosenhctin. 
Phil. Trans.. A., 
Vol. /p5, Plate 10 . 
Fig. 27.—Crushed lead, after pi-olonged annealing, x 8. 
Fig. 28.—Tin-plate, etched, x -A-. 
Fig. 29.—Tin-plate, etched. X 100. 
