Testing Mustard for Turmeric
Place 1 gm. of ground mustard on a small watch glass and moisten slightly with water. Add 2 or 3 drops of NH4OH, stirring well with a glass rod. A brown color indicates turmeric present in considerable quantity.
Test a sample of good mustard and one adulterated with turmeric and compare the results.
Experiment No. 39
Examination of Tea Leaves
Soak a small amount of tea and unroll 8 or 10 of the leaves. Make a drawing of a tea leaf. Observe the proportion of stems in each of three samples of tea; also the relative proportion of large and small leaves. Observe if the leaves are even as to size and of a uniform color.
Experiment No. 40
Action of Iron Compounds upon Tannic Acid
Make an infusion of tea by placing 3 gms. of tea in 100 cc. of hot water and stirring well. Filter off some of the infusion and test 5 cc. with ferrous sulphate solution made by dissolving 1 gm. FeSO4 in 10 cc. H2O and filtering. Note the result.
1. What change in color did you observe when the ferrous sulphate solution was added to the tea infusion? 2. What effect would waters containing iron have upon the tea infusion?