PLUMBING 75 



c. With white paint make a small spot on some black goods. 

 To remove the paint spot soak it in a teaspoonf ul of gasoline or 

 benzine. These liquids dissolve the linseed oil of the paint 

 (cf. 229, text). Let the cloth dry; then brush off the white 

 powder that remains. What is the powder? 



d. With grass or some other green plant make a stain on 

 white muslin. Soak the stain in a little alcohol, and rub the 

 spot with a clean white cloth. Result? 



EXERCISE 72 

 PLUMBING 



Apparatus and Materials. Sample or demonstration faucets, 

 plumbing trap, piece of old lead pipe or trap. 



a. Examine Fig. 28. If you were closing the "compression" 

 faucet, would the water pressure in the pipe help to close the 



Fia. 28 



The faucet on the left is a Compression faucet, the one on the right, a Fuller faucet. 

 Both are cut open so that we can see how they work. Courtesy of the Central Scientific 

 Company, Chicago. 



faucet, or would you have to overcome the water pressure? 

 Which would be the case with the "Fuller" faucet? What simple 

 machines are used in the opening and closing of these two faucets? 



