MANUFACTURE OF PLASTERS. 



53 



Analyses of gypsum used in actual practice. The following analyses 

 of both rock gypsum and gypsite (gypsum earth), taken from various 

 sources, will be fairly representative of the materials used for plaster at 

 different plants. For comparison it is well to recollect that a theoret- 

 ically pure gypsum would consist of lime sulphate 79.10 per cent, water 

 20.90 per cent, and would contain no silica, alumina, iron oxide, lime 

 carbonate, or magnesium carbonate. 



TABLE 8. 

 ANALYSES OF ROCK GYPSUM USED FOR PLASTER. 



1. Gypsum Station, Calif. 



2. Blue Rapids, Kansas } used at Great 

 3 " " \ Western Plas- 



4. " " " J ter-mill. 



5. Dillon, Kansas. 

 6. 



7. Hope, Kansas. 



8. 



9. " 



10. Solomon, Kansas. 



11. " " 



12. Medicine Lodge, Kansas. 



13. Alabaster, Michigan, used at 



Plaster Works. 



14. Grand Rapids, Mich. 



15. " 

 16. 



17. Alabaster, Mich. 



18 Near Sandusky, Ohio. 



19- " 



20. " 



21-24. Saltville, Virginia. 



25. Hillsboro, New Brunswick. 



26. Baddeck Bay, Nova Scotia 



