2 2 ELEMENTS OF /IPPLIED MICROSCOPY. 



In some microscopes the two lenses of the eyepiece 

 work together to produce the effect shown in Fig. ii. 

 More commonly, however, the real inverted image is 

 formed between these two lenses, and only the upper 

 one forms the virtual image. In such an eyepiece, 

 known as a negative or Huyghenian ocular, the lower 

 or field lens really forms part of the objective system. 



REFERENCES. 



Batjsch, E. Manipulation of the Microscope. Rochester, 1901. 

 Caepenter, W. B., and Dallinger, W. H. The Microscope and 



its Revelations. London, 1901. 

 Clark, C. H. Practical Methods in Microscopy. Boston, 1894. 

 Gage, S. H. The Microscope. Ithaca, N. Y., 1904. 

 Hagee, H., and Mez, C. Das Mikroskop und seine Anwendung. 



Berlin, 1899. 

 These references, and those appended to other chapters, include 

 only those few books which have been, found most indispensable in 

 the work of the course in Industrial Microscopy as given at the In- 

 stitute of Technology. A very full bibliography of works on 

 microscopy will be found in Professor Gage's book cited above. 



