208 COAL-TAR COLORS USED IN FOOD PRODUCTS. 



5. The ether extractives are to be made successively upon water solutions of the 

 dye, first neutral, then made alkaline with caustic soda, and then made acid with 

 hydrochloric acid, using washed or sodium, dried ether. 



6. The sulphur content of the sulphur-containing dyes must agree substantially 

 with the theoretical; likewise the sulphated ash figures of all must agree substantially 

 with the theoretical; variations between these two sets of figures, as long as they are 

 consistent with each other, will not be reason for rejection. 



7. In the case of No. 4 proof must be submitted showing that the specimen is of the 

 sodium or potassium variety, and if it is a mixture of these two varieties the proportion 

 of each present in the mixture must be stated. 



8. In the case of No. 56 the crude cumidin employed may have a boiling point of 

 from 220 to 230 C., and may be liquid or solid; the absence of any compound of 

 S or G salt must be convincingly shown. 



9. In the case of No. 85 convincing proof must be submitted that beta-naphthol 

 orange if present at all is present in an amount not in excess of 5 per cent of the coal- 

 tar dye present. 



10. In the case of No. 107 the absence of any compound of S or G salt must be 

 convincingly shown. 



11. In the case of No. 435 the product should be free from calcium; convincing proof 

 of absence of No. 434 must be submitted. 



12. In the case of No. 517 the actual dye must contain not less than 56 per cent of 

 iodin (sodium basis) and must not contain any other halogen; the kind and amount 

 of metallic base, whether sodium, potassium, or the like, must be shown. 



13. In the case of No. 692 the absence of indigo monosulphonic acid and of nonsul- 

 phonated indigo must be convincingly shown. 



14. Each foundation certificate must be filed in duplicate, but need not be executed 

 in duplicate and must contain a summarized or tabulated statement of all the quan- 

 titive results contained in the certificate, also a tabulation or summary of the quali- 

 tative tests made, together with the results of such tests, all stated on one sheet, so 

 that the certificate will bear within itself its own summary and conclusions. 



15. The fundamental analytical data must be given with such fullness as to permit 

 efficient checking of the calculations, and the arithmetical operations performed 

 should be indicated wherever needful to avoid confusion, or to facilitate the work of 

 the checking chemist, or make the meaning of the certificate more plain. 



There are freely quoted in the United States market two substances, 

 paranitranilin and betanaphthol, which are subject to much com- 

 petition, the prices for which, wholesale, are not far from 25 cents 

 and 9 cents, respectively. A specimen of each has been examined, 

 and, as before stated, they have both been found to be of such 

 purity, with respect to arsenic, heavy metals, and general cleanliness, 

 that had they been capable of use in food products, no objection 

 against their use on this score could reasonably be raised; certainly 

 no such objection could be successfully maintained. 



The following table discloses the chemicals entering into the manu- 

 facture of paranitranilin and of betanaphthol, as well as of each 

 of the seven permitted colors; the ingredients numbered 1 to 7 are 

 used in the manufacture of these two substances, as well as in the 

 seven permitted colors, as indicated by the "x" entries; ingredients 

 8 to 20 are used only in the manufacture of the seven permitted 

 colors, and not in paranitranilin and betanaphthol. 



