62 



198. Tintometer. An instrument for measuring 'colour. 

 E. 42. 1889. Made by J. W. Lovibond. 



This is an instrument by which the depths of colour in liquids 

 and solids are measured accurately in degrees. 



It consists of a series of standard scales formed by choosing a 

 glass faintly tinted of the colour to be standardized and con- 

 sidering this a single unit or degree of colour (basing it where 

 possible on a per-centage solution of some known substance 

 similar in colour) then building up a scale by the addition of 

 successive units of the same colour value ; and an instrument 

 for holding the glasses and object to be measured. 



The instrument consists of two tubes side by side, both open 

 at one end, one tube giving a view of the object to be measured, 

 and the other a view of the standard glasses. At the other end 

 of the instrument is a single eye piece commanding a clear 

 vision at the same time of the object on one side and measuring 

 glasses on the other under exactly similar conditions uninfluenced 

 by the nature and colour of the surroundings. 



For measuring solids a white back ground of plaster of Paris 

 (pure) pressed in a tray, is used for the standard glasses to work 

 against. 



In the case of woollen fabrics, &c., the fabric is wound on a 

 block and measured against a white fabric of similar texture on 

 another, the white being first measured against pure plaster of 

 Paris. 



For liquids the instrument is placed opposite the white re- 

 flecting mirror. 



The liquid is poured into one of the gauged glasses, choosing 

 a size which will give a medium reading (under 12 degrees is 

 best for very critical examination). Standard glasses are then 

 placed in the grooves on the other side until equality is obtained, 

 when the numbers on the glasses will indicate the colour with 

 its combinations and depth of tint, as in the case of solids. 



If the colour is not matchable by glasses of a single series or 

 colour, the deficient colour must be guessed and added. 



In reading, the small figures on the slip indicate the colour, 

 and the large figures give the degrees of colour in each glass. 



For measuring opaque fabrics, the instrument is fixed in a 

 sloping stand, with the light equal on both sides, and is then 

 used as described above for solids. 



199. Soxhlet's fat extraction apparatus. Price II. 2s. 6d. 

 1886. Exhibited by F. E. BecJcer $ Co. 



This apparatus is used for extracting oils from seeds, &c., but 

 is capable of numerous other applications. A flask containing 

 ether or other volatile solvent substance is heated by a spirit 

 lamp. Fitted to the neck of the flapk is the Soxhlet tube, which 

 is a kind of large test-tube, furnished with a siphon externally 

 and a side tube. Above this tube is an upright Liebig's con- 



