BAIRJD &I?STLOCK (LONDON) LTD. 



ZEISS' REFRACTOMETER EQUIPMENT FOR THE INVESTIGATION OF 



SUGAR SYRUPS. 



4984 T Abbe Refracto meter (Fig. 4983), with beatable prisms, ;n lock-up case, with conversion 

 tables and i thermometer 0-75 C., 



4985 T Accessories for the production of a constant temperature in a current of warm water, 



consisting of a spiral heater and water-pressure regulator 

 In addition, for use where water is not laid on : 



4986 T Pump, with hot-air motor, for raising the warm water from the refractometer into the 

 water-pressure regulator 



4987 T If desired, instead of the above thermometer, one, from 0-45 C. divided in , is supplied, 

 fitted in a specially wide screw connection by means of a short thick piece of rubber tubing, 

 and which does not break easily on receiving a shock 



MANIPULATION. 



A few drops of the substance are enclosed in the Abbe double prism AB, which has a current of water at a 

 constant temperature circulating through it. After adjusting the border line of total reflection upon the point of 

 intersection of the reticule in telescope F (no skill required), the refractive index no to within two units of the 

 fourth decimal is read off on the graduation of the sector j with the aid of the lupe t, and the temperature as- 

 certained on the thermometer. By means of a table the refractive index is converted into a percentage of dry 

 substance. The entire investigation requires only a few minutes, and is very easily learned. 



20 5 



3 13 



2 10 



7 < 



4989 (section) 



4989 s Jean's Oleorefractometer, for the analysis of butter fats, oils, glycerine, turpentine, etc. 

 Price in mahogany case 



4990 s Standard oil for above . . . . . . : . . . . . . . per Ib. 



THE OLEOREFRACTOMETER AND ITS USES. 



(Extract from Dr. Muter's article in Analyst, May 1890, pp. 87-89.) 



The analysis of oils and fats is practically carried out by three observations : (i) The density ; (a) the ther- 

 melseometre as above described ; (3) by the important instrument with which we are now about to deal, the 

 construction of which will be evident on studying the drawing. 



The centre of the instrument is formed by a circular metallic receptacle F, closed by two opposite lenses LL, 

 from which extend two tubes B, G, the one ending in a collimator A, and the other in a short-visioned telescope 

 i. In the middle of the receptacle is placed an inner metallic reservoir E, having glass sides placed at a suitable 

 angle, so as to form a prism. In front of the field-glass of the telescope is a photographic scale. Fig. 3 , and there is also 



CROSS STREET HATTOT GARDETST, E-C 



900 



