138 EXPERIMENTAL GENERAL SCIENCE 



32. In making certain kinds of perfumes, fresh flowers are placed in 

 closed vessels whose walls are covered with a layer of lard or other fat. 

 Later the perfume is found in the fats. How did it get there? 



33. Place a crystal of copper sulphate in a test-tube and heat slowly. 

 Explain the source of the substance that forms on the cooler part of the 

 tube. 



34. In making alloys, how does melting the metals form an alloy 

 more rapidly than if the two solids were placed together? 



35. Milk is a natural emulsion. Can you discover what substance in 

 the milk corresponds to the kerosene in kerosene emulsion? 



36. How dp soap and water aid in taking grease out of clothing? 



37. Cleaning fluid is usually made of several fluids mixed together. 

 Why is this? 



