16 



A. PRELIMINARY TESTS. 

 a. EXAMINATION FOR NATURAL OR ARTIFICIAL COLORING MATTERS. 



Reagent. 



Reactions for normal wine, i Reactions for suspicious wine. 



1. Add ammonia to 20 cc of wine 



until alkaline, then a few 

 drops more, agitate, pour 

 into glazed porcelain dish. 



2. Add subacetate of lead in 



slight excess to 20 cc of wine, 

 about 6 cc to 8 cc, agitate 

 and filter. 



3. Add 5 cc of 10 per cent solu- 



tion of alum to 10 cc of wine, 

 to which has been added 

 previously a weak solution 

 of potassium carbonate (until 

 the color does not deepen), 

 then add 5 cc of a 10 per 

 cent solution of potassium 

 carbonate. (Neutralization 

 must be assured.) 



4. Add 10 cc of saturated solu- 



tion (in the cold) of alum to 

 10 cc of wine, and then, drop 

 by drop, a concentrated solu- 

 tion of neutral acetate of 

 lead until precipitation is 

 complete, and filter. 



5. Agitate 10 cc of ether and 10 cc 



of wine in a test tube. 



6. Add 10 cc of solution of alum 



2 B. to 10 cc of wine pre- 

 viously brought to a violet 

 tint by addition of potassium 

 carbonate. 



7. Small bit of fulminating cotton 



is placed in a tube with 20 cc 

 of wine and agitated for a 

 minute or two, well washed 

 with distilled water, and 

 dried. 



8. Fifty cc of wine made just 



alkaline with baryta water, 

 then 25 to 30 cc of neutral 

 amvl alcohol. Agitate sev- 

 eral times and allow to settle. 



9. Add 40 centigrams of yellow 



oxid of mercury finely pul- 

 verized to 20 cc of wine, 

 heat to boiling, and filter 

 through double filter paper. 



10. Equal weights of dioxid of 



manganese natural, pulver- 

 ized, and wine are agitated 

 for 5 minutes, then filtered. 



11. Boil a small piece of flannel, 



well bleached and washed, 

 with 20 to 30 cc of wine; 

 evaporate to dryness, wash 

 flannel with distilled water, 

 and observe the color; then 

 treat with ammonia. 



Greenish blue; green or yel- 

 lowish green; yellowish with 

 some brown (old wine). 



Precipitate varying from gray- 

 ish blue to greenish blue or 

 gray; filtrate colorless. 



Lake colored bottle green with- 

 out blue or violet tint; filtrate 

 uncolored, green, or lilac, in 

 the latter case becoming 

 green on adding sodium car- 

 bonate. 



Filtrate light wine color 



Ethereal layer colorless 



Mixture wine-colored lilac,, 

 very intense, or garnet. 



Cotton white or faint wine red, 

 becoming green with am- 

 monia. 



Amyl alcolwl colorless, a fil- 

 tered portion remaining so 

 when acetic acid is added. 



Filtrate colorless, remaining so 

 after adding acid; residue, 

 treated successively with 

 boiling water, alcohol, and 

 amyl alcohol, does not color 

 either solvent. 



Filtrate colorless or yellow Filtrate rose color, 

 tinted. 



Red brown; garnet; reddish 

 black; reddish green. 



Precipitate deep green, green, 

 red green, or grayish red; 

 filtrate uncolored, or more 

 often colored. 



Lake is colorless, violet, or rose; 

 filtrate is blue, violet, or rose, 

 and does not turn green on 

 adding potassium carbonate. 



Filtrate blue, violet, gooseberry 

 blue. 



Ethereal layer yellow or violet. 

 Ammonia added to the ethe- 

 real layer gives yellow to red 

 (campechy), violet to deeper 

 violet (archil). 



Mixture violet blue. 



Cotton rose, red brown, or blue, 

 disappearing on addition of 

 ammonia and not becoming 

 green. 



Amyl alcohol colored, or be- 

 comes colored rose, yellow, 

 or violet with acetic acid. 



Filtrate colored, or becoming so 

 when acidified; residue treat- 

 ed in same manner with sol- 

 vents colors some or all of 

 them. 



Wool faintly colored like wine 

 lees; treated with ammonia 

 yellowish green. 



Wool colored. 



a MM. Fortes et Ruyssen, Trait6 de la Vigne. 



