CH. VI] MICRO-METALLOGRAPHY 183 



yarns and fabrics. Philadelphia and London, 189L Dr. C. Rougher — Des 

 filements veg£taux employes dans l'industrie. Paris, 1873. Wm. P. Wilson 

 and E. Fahring — , The conditioning of wool and other fabrics in the techno- 

 logical laboratories of the Philadelphia Commercial Museum. Journal of Ap- 

 plied Microscopy, Vol. II, (1899) pp. 290-292, 457-460. Bulletin of the 

 National Association of Wool Growers, 1875, p. 470. Proceedings of the Amer 

 Micr. Soc, 1884, pp. 65-68. Hanausek and Winton. The Microscopy of 

 Technical Products ; Winslow, Elements of Applied Microscopy, excellent on 

 foods, drugs, textile fibers, paper. Besides these references one is liable to 

 find pictures and discussions of various fibers in general works on the 

 microscope, and in technical and general cyclopaedias. 



The microscopical Journals also contain occasional articles bearing upon 

 this subject. See also Food Products in bulletins of theU. S. Dep't Agr. Mace\ 

 E. — L-essubstancesalimentaire, etc., Paris, 1891. Schimper, A. F. W. Anleit. 

 ung, etc. Jena, 1900. HughGalt, — TheMicroscopy of the starches, illustrated 

 by photo-micrographs, London, 1900. Winton and Moeller, the Microscopy 

 of Vegetable Foods. Greenish, Micr. Ex. Food and Drugs.; Wiley, Foods 

 and their Adulterations. (See also the other works in the Bibliography at the 

 end. ) 



THE MICROSCOPE IN METALLOGRAPHY 



\ 257. In the modern investigation of metals and alloys much light has 

 been thrown upon the structural peculiarities which render some mixtures 

 satisfactory and others unsatisfactory. There are two great methods: First, 

 that of studying fractured surfaces without recourse to any reagents. Second, 

 to polish a metallic surface carefully with emery or carborundum and finally 

 with rouge or diamantine and then etch it with some acid for a longer or 

 shorter time. For either method reflected light must be used. For low powers 

 that obtained at a good window or by a lamp or a lamp and bulls eye are good. 

 The illuminating objectives (§31), i. e. objectives in which a prism or reflector 

 in the objective reflects light down through the lenses which act as a conden- 

 ser, are preferable for most work and indeed necessary if one uses high powers. 



Elaborate arrangements have been devised for holding the piece of metal 

 on the stage, but some beeswax, or some clay made plastic with glycerin 

 answers well. For pictures of the appearances seen in studying metallic 

 surfaces, see the journals of engineering and metallurgy, especially the 

 Metallographist, a quarterly publication devoted to the study of metals with 

 special reference to their physics and micro-structure, etc. In twenty-five or 

 more of the great metal manufacturing establishments special laboratories for 

 microscopic examination and investigation have been established. This is an 

 illustration of what has frequently occured— great manufacturing interests 

 have outrun the universities in the appreciation and application of methods of 

 research. Fortunately, however, laboratories are already springing up in 

 connection with the universities, and probably within a few years every great 

 technical school will have its laboratory of micro-metallography where students 



