VI. FLUORESCENT BODIES. 199 



reading of the refractive index, without calculation. (Comp. 

 Abbe : " Neue Apparate.") 



Franz Schmidt and ffaensck, Berlin- 



920. The same, smaller model. 



Franz Schmidt and Haensch, Berlin. 



921. Apparatus, according to J. Muller's principles, for 

 experiments as to the refraction of rays of light in fluids, 



all of glass. Warmbrunn, Quilitz, and Co., Berlin. 



92 la. Apparatus by M, Mascart for studying the refraction 

 of gas. M. Mascart, Professor at the College of France. 



92 Ib. Apparatus for determining the Refraction Index 

 of Solids and Liquids. 



C. Czechovicz, teacher of Physics at the Gymnasium of 

 Be lost ok, Russia. 



Consists of a horizontal board and vertical divided pillar with movable 

 support for a telescope. The body under examination is put on a glass plane 

 attached over a slit in the board, through -which a light beam is reflected by 

 an inclined mirror. A linear mark made on the upper surface of the glass 

 (if the body is solid), or on the upper surface of the vessel (if the body is 

 liquid), is brought in coincidence with a movable wire which touches the' 

 upper plane of the body. The distance of this wire and the height and incli- 

 nation of the telescope give the necessary data for calculating the index with 

 sufficient approximation. 



VI. FLUORESCENT BODIES. 



922. Fluids showing the Phenomenon of Fluorescence. 



Charles Homer. 



A. Soda salt of anthracene in water. 

 33. Fluorescine in water. 



C. Eosine in water. 



923. Fluids showing the Phenomenon of Fluorescence. 



Charles Homer. 



Small Tubes in Stand. 



D. Turmeric in castor oil. 



E. Harmaline in water. 



F. Magdala red in alcohol. 



G. Ebony wood (Amerimuum ebenus} in castor oil. 

 H. Inuline in chloroform. 



I. Esculine in water. 



K. Camwood (Baphia nitidd) in castor oil. 



L. Esculetine in water with alkali. 



M. Fraxine (Fraxinus excelsior} in water. 



N. Fustic (Madura tinctoria) in solution of alum. 



