CREAMERY BUTTER MAKING 177 



from scale. The kind of compound to be used is deter- 

 mined by the character of the impurities of the water. 

 Most creameries use well water for the boiler and the 

 chief impurity in this is lime. The best compound for 

 water of this kind is soda. Well water contains the lime 

 in widely different proportions. In order, therefore, to 

 ascertain the proportion of soda to feed water the fol- 

 lowing method is recommended by Hawkins : 



"i. Add one sixteenth part of an ounce of soda to a 

 gallon of the feed water and boil it. 2. When the sedi- 

 ment thrown down by the boiling has settled to the bottom 

 of the kettle, pour the clear water off and add one-half 

 drachm of soda to this. Now, if the water remains clear, 

 the soda which was put in has removed the lime. But 

 if it becomes muddy, the second addition of soda is neces- 

 sary." In this way the amount of soda to be added to 

 the feed water can be calculated with sufficient accuracy. 



Tan bark is very efficient in removing boiler scale but 

 may injure the iron. 



Kerosene answers the same purpose but renders the 

 steam unfit for use in the creamery. 



When the water is salt or acid, a piece of metallic zinc 

 occasionally placed in the boiler will prevent corrosion. 

 Water of this kind can usually be told by its corrosive 

 effect on copper and brass. Acid water can also be de- 

 tected with blue litmus paper, which it turns red. 



WET AND DRY STEAM. 



Wet steam. This is steam holding in suspension 

 extremely small particles of water which are thrown off 

 from the water surface while steam is generating. The 

 following are the causes of wet steam : 



