ON THE CRYSTALLINE STRUCTTTIE OF METALS. 375 



PLATES 24 AND 25. 



Fig. 32. Distorted crystalline grains in a transverse section of cold-rolled Swedish 



iron, also showing geometrical etched pits. 200 diameters, vertical light. 

 Fig. 33. A portion of the large distorted grain in Fig. 32, more highly magnified; 



the enlarged portion is at the angle of the distorted grain. 800 diameters, 



vertical light. 

 Figs. 34, 35, and 36. Slip-bands in twin crystals of copper. 1000 diameters, vertical 



light. 



Fig. 37. Slip-hands in twin crystals of gold. 200 diameters, vertical light. 

 Fig. 38. Slip-hands in twin crystals in gold. 45 diameters, ohlique light. 

 Fig. 30. Slip-binds in twin crystals of cold-hammered copper. 1000 diameters, 



vertical light. 



PLATE 26. 



Fig. 40. Slip-bands in twin crystals oliserved in a specimen of plumbers' sheet-lead. 



1000 diameters, vertical light. 



Fig. 41. Slip-bands and twinning in nickel. 1000 diameters, vertical light. 

 Fig. 42. Elongated crystalline grains in cadmium cast on a sloping surface of glass. 



Transverse twin liands developed by slight straining are seen to run across a 



number of adjacent grains, with slight changes of direction on crossing a 



Ixnmdary. 100 diameters, vertical light. 

 Fig. 43. Glass-cast surface of cadmium, showing double system of Ixnindaries. 



100 diameters, vertical light. 



PLATES 27 AXD 28. 



Fig. 44. High-power appearance of real and pseudo-l>oundarie8 as indicated by slip- 

 bands. 1000 diameters, vertical light. 



Fig. 45. Strained mild-steel, showing "pearlite" patches and slips in "ferrite" areas. 

 1000 diameters, vertical light. 



Fig. 46. Glass-cast and etched surface of lead-tin eutectic. 750 diameters, vertical 

 light, 



Figs. 47 and 48. Glass-cast and strained (but unetched) lead-tin eutectic. 750 

 diameters, vertical light. 



Fig. 49. Slowly-cooled lead-bismuth eutectic, etched and strained, showing slip-liands. 

 1000 diameters, vertical light. 



Figs. 50 and 51. Slip-bands in crystallites found in lead-bismuth alloy. 1000 

 diameters, vertical light. 



