lU8 SUMMARY OK CURRKNT RliSKARCIlES RELATING TO 



side in contact with the table. The under side of the tray is fitted with 

 " domes of silence," and can be revolved on the centre-pin, the lamp 

 being placed on the wooden circle over the centre and revolving with 

 the Microscope, and therefore maintaining its position constantly in 

 relation to the instrument. It will be readily seen that a device of this 

 description allows of several people using the same Microscope in succes- 

 sion with the minimum of inconvenience. The whole tray and contents 

 can be moved bodily without trouble when desired. It is constructed 

 in oak wax polished. 



C4) Photomicrogrraphy. 



Photomicrography in Natural Colours.* — E. Wychgram gives an 

 historical review of the progress in this branch of science, together with 

 some practical advice. A plate of five coloured photomicrographic 

 objects illustrates his remarks. He also adds a bibliography of the 

 appropriate literature. 



(5) Microscopical Optics and Manipulation. 



Pulfrich's Stereoscopic Vision and Measurement.f — Under the 

 title Steroskopisches Sehen und Messen, C. Pulfrich has brought out a 

 German version of his article. The Stereoscope, contributed to the last 

 edition of the Encyclopaedia Britannica. He has, moreover, added to it 

 a bibliographical index of all publications on Stereoscopy which have 

 appeared during the last 11-12 years. Anyone wishing to consult earlier 

 sources of information should have recourse to the similar article in 

 M. von Rohr's Die binokularen Instrumente.f 



General Theory of the Microscopical Image. § — In this work of 

 over 400 pages, J. M. Castellarnau yde Lleopart discusses present views 

 of the microscopical image. In a somewhat lengthy preface he acknow- 

 ledges his indebtedness to the Journal of the Royal Microscopical 

 Society, especially to the discussions and papers therein recorded. He 

 also acknowledges his obligations to well-known eminent German 

 authorities. After describing the path of the rays in the Microscope 

 and the dioptric properties of the image (Part I.), he deals with the 

 genesis of the microscopical image and the laws of its correspondence 

 with the object (Part II.). In Part III. he deals with the experimental 

 demonstration of the theory of image formation. In a group of five 

 appendices he discusses certain important optical properties. The book 

 contains numerous diagrams, and has the appearance of having been 

 very carefully compiled. 



* Zeitschr. wiss. Mikrosk., xxviii. (1911) pp. 174-82 (1 pi. and 5 col. figs.). 

 t Jena : Fischer (1911) 40 pp. (17 figs.). 

 X Berlin, 1907. 



§ Teoria general de la Pormacion de la Imagen en el Micrcscopio per D. 

 Joaifiiin l\Ia Castellarnau y Lleopart. Piih. by E. Arias, Sladrid (1911). 



