PLASTIC MATERIALS IN TELEPHONE USE 501 



A few of the new thermoplastics are quite inflammable, a charac- 

 teristic that will be a serious handicap to their extended use in ex- 

 changes and other locations where a fire might disrupt the service of a 

 whole community. 



There are still certain weaknesses of organic finishes with respect to 

 impact abrasion, perspiration and moisture penetration, although there 

 have been great advances made in this field in recent years. 



