10 



DIRECTIONS FOR CONDUCTING TEST. 

 To Test Butter. 



i. Set up the apparatus* just as it appears in the cut. 



2. Fill the condenser with cold water. 



3. Obtain a representative sample of butter and place it in the 

 sampling cup, L. Heat carefully, either in hot water or over the alcohol 

 flame, stirring- continuously with the spoon provided until the butter is 

 all melted to a creamy consistency. 



4. Place the evaporating- cup, A, on the scale pan and balance it 

 by means of the counterpoise on the opposite beam. Place the 10 gram 

 weight on the other scale pan and after again stirrinp- the sample thor- 

 oughly, transfer sufficient of it to the cup to exactly balance the 10 gram 

 weight. 



5. Using the graduate, f3, add 10 cubic centimeters (c.c.) of the 

 reagent to the cup from the bottle fi. 



6. Connect the cup with its lid a2. 



7. Apply the alcohol flame ( a fairly large flame) to the evapora- 

 ting cup — the lamp can be readily adjusted by moving it on the upright. 

 In about one minute the water and reagent will begin to pass over and 

 drop from the condenser tube, b2, into the receiver, C. After all the 

 water has been evaporated from the cup the reagent will cease, or 

 almost cease, dropping for a moment and then begin again as soon as it 

 has reached its own boiling point, which is higher than that of water. 

 Continue to apply the flame until practically all the reagent is driven off 

 and it ceases to drop freely from the condenser tube. By this means all 

 the water is washed out of the condenser tube and the major portion of 

 the reagent is recovered. Now swing- the alcohol lamp to one side and 

 put its lid on. 



8. Immediately remove the receiver, C, cork its. mouth and, taking 

 it by the top, swing it carefully a few times to detach any drops of water 

 that may be adhering to its sides. Read the percentage of moisture 

 direct from the scale, taking the bottom of the meniscus between the 

 water and reagent as the top of the water line. Should any particles of 

 moisture still adhere to the side of the tube, or the meniscus be imperfect, 

 the wire accompanying the apparatus can be used to remedy this. 



9. Have two reagent bottles and label them 1 and 2. 

 No. 1 contains the reagent ready for use. 



No. 2 is for the used reagent. 



10. When emptying the receiver, C, first open the stopcock to allow 

 all the water to run out, then close it and then hold the receiver over 

 bottle No. 2 and allow the used reagent to run into it. The receiver, 

 after being shaken, is ready for use again. 



11. Bottle No. 2 is necessary for keeping the used reagent separate 

 from the other, since it has absorbed a small amount of moisture from 



