3<56 THE AMERICAN MONTHLY [Dec 



WheneTer possible they should be suspended on hooks or 

 lines or so spread that the largest jjossible surface is ex- 

 posed. Leather goods, trunks, suit cases, etc., may be sub- 

 jected to 90° C, dry heat, without injury. The elasticity 

 of rubber is apparently not diminished. 



OUTLINE OF METHOD. 



1. Heat jacket with steam so that temperature of 

 ehamber is 90° C. 



2. Pour into formalin generator one-fourth as many 

 c. c. of formalin mixture as there are liters capacity in 

 chamber, e. g. 625 c. c. for a chamber of 2,500 liters 

 capacity. 



3. Obtain a vacuum of 15 inches or one-half an at- 

 mosphere. 



4. When pressure in generator reaches 40 to 60 pounds 

 open the valve just enough to allow a gradual reduction of 

 pressure by the passage of formaldehyd into the chamber. 

 If this valve is opened too wide the fluid may be driven 

 into the chamber and its contents injured. 



5. When it is found that all the gas is driven oflF.close 

 the valve to the chamber. 



6. Maintain temperature of chamber at 90° C, or 

 even higher, by allowing steam to course through jacket. 



7. At end of thirty minutes the vacuum may be broken 

 and the mixture of air and formaldehyd exhausted. 



8. With a vacuum of 10-15 pounds the ammonia gen- 

 erator may now be operated in the same manner, using 

 one-half as much ammonia water as of the formalin mix- 

 ture. 



9. After the ammonia gas has entered the chamber the 

 vacuum may be at once broken and the chamber opened. 



10. Each time, after the formalin generator is opera- 

 ted, it should be thoroughly cleansed with water. If the 

 sirnpy residue is not removed it soon fouls the apparatus 

 and clogs the outlet. 



