1920 



Journal of Applied Microscopy 





LABORATORY PHOTOGRAPHY. 



Devoted to Methods and Apparatus for Converting an Object into an Illustration. 



PHOTO-MICROSCOPY OF METALS AS PRACTICED BY 

 STEEL COMPANIES. 



When Henry Clifton Sorby of England reported the results of his study of 

 the structure of meteoric and artificial irons at a meeting of the Iron and Steel 

 Institute in 1864, in a paper " On the Microscopical Structure of Meteors and 

 Meteoric Iron," very little attention was paid his report. After a lapse of twenty- 

 two years the Institute requested Dr. Sorby, Dr. Percy, and Sir Henry Bessemer 

 to decide what was the best way of illustrating a complete paper on the micro- 

 structure of iron and steel. As the result of this investigation. Dr. Sorby 

 presented two papers to the Iron and Steel Institute " On the Microscopical 

 Structure of Iron and Steel." Since that time this means for the examination of 

 metals and their alloys has increased in importance and value and within the last 

 decade has become a recognized department in the testing laboratories of many 

 industries, especially those of producers and users of iron and steel. 



An equipment for the study of metal-microscopy or metallography consists of : 

 a means for the preparation of the micro-section ; reagents to " etch ' the spec- 

 imen ; a compound microscope, which, in addition to the usual accessories, is 

 equipped with a vertically movable stage and a means for '■ vertical illumination " ; 

 a light, strong, steady, and of uniform intensity, and a camera adapted to use with 

 a microscope. 



The piece of steel to be 

 examined and photographed, 

 having been machined to a 

 suitable size for use on the 

 microscope stage (the most 

 convenient size and shape 

 being either cylinders or 

 cubes of about one-half inch), 

 the surface to be examined is 

 filed to a true plane and the 

 polish is continued on suc- 

 cessively finer grades of em- 

 ery-cloth stretched over plane 

 surfaces. It is well to change 

 the direction of the applica- 

 tion of the abrasive with each 

 change in fineness, so that 

 each set of scratches is at 

 Fic;. 1.— Pig Iron Polished in Relief. right angles with the previous 



