PETER SPENCE 267 



8. Separation of various metals from their 



ores. 



9. Purification of Gas. 



10. Production of Salammoniac. 



1 1. Manufacture of Sulphocyanide of Am- 



monium. 



12. Manufacture of White Lead. 



13. Treatment of Phosphate of Alumina 



and Iron. 



14. Treatment of Sewage. 



1 5. Manufacture of Manure. 



1 6. Treatment of Bauxite, and the Manu- 



facture of Aluminoferric Cake, 



17. Purification of Water. 



1 8. Treatment of Gases arising from the 



manufacture of Salts of Ammonia 

 from Gas Liquors. 



19. The Use of Oxide of Manganese in 



the manufacture of Salts of Am- 

 monia from Iron. 



20. Obtaining Power by Steam. 

 2 i . Repairing Fractured Bells. 



Most of the above are the subjects of more 

 than one patent, some of several, and the 

 same subject is treated after the interval of 

 several years. Some of the patents are 

 modifications of preceding patents, others put 

 forth entirely new ideas. Some had little or 



