202 



COAL-TAR COLORS USED IN FOOD PRODUCTS. 



by the manufacturers pointed in the direction of the impossibility of 

 getting rid of all the sodium sulphate; but later and more extended 

 work showed this conclusion to be an error. There is therefore no 

 good reason for permitting sodium sulphate as a contaminant in this 

 or any other of the seven products. 



CONFORMITY OF ANALYTICAL DATA WITH THEORETICAL COM- 

 POSITION. 



The seven tables following, likewise based upon the 74 Govern- 

 ment analyses, show the conformity or nonconformity, as the case 

 may be, of these samples with their theoretical composition. The 

 second and third columns show the percentage based on theory of 

 the contained sulphur and sodium in the case of all colors except 

 Erythrosin, where the figures for iodin are substituted for those of 

 sulphur. The fourth column shows the actual ratio of sodium to sul- 

 phur or iodin, as the case may be, and the fifth column gives the 

 percentage of the figure of column 4 based on the theoretical value 

 which is given in parentheses at the head of columns 4 and 5. The 

 summary gives the maximum, minimum, and average of each column. 

 Taken as a whole the figures are fairly satisfactory and show a rea- 

 sonable conformity of the actual product to theoretical requirements, 

 although there seems to be considerable room for improvement, which 

 no doubt can be achieved in time. 



Percentages based on theoretical composition. 

 NAPHTHOL YELLOW S. 



PONCEAU 3R. 



