54 



the ounce it must be diluted with an equal quantity of 

 water, and the number of grains per ounce multiplied by 

 two. 



A very similar preparation, accurately compounded, 

 is on the market under the name of Whitney's Reagent. 

 It is for sale by the Norwood Chemical Co., 105 W. 40th 

 St., New York. 



The following table gives the amounts of sugar in 



analytical testing with Whitney 's Reag^t : X » 



If reduced by It contains to the oz. / Percentage. 



Quantitative Test hy Benedict's Method. In the 

 quantitative method Benedict uses three separate solutions. 

 The Cupric sulphate solution and the Alkaline tartrate 

 solution are the same as those already described for his 

 qualitative test, (see p. 38). The third solution is the 

 Potassium ferro-thiocyanate solution and is made up as 

 follows : 



Potassium ferrocyanide - - 15. grams 

 Potassium thiocyanate - - 62.5 " 



Anhydrous sodium carbonate - 50. " 

 Water up to . . - . 500. cc. 



The three solutions should be preserved separately in 

 rubber-stoppered bottles to prevent deterioration and 

 mixed in equal volumes when needed for use. 



Application. To 30 cc. of Benedict's solution in a 

 small beaker add from 2.5 grams to 5 grams of anhydrous, 

 sodium carbonate and heat the mixture to boiling over a 



