The Gila alum contains about 28 per cent…
source date: 1890
availability: public-domain

The Gila alum contains about 28 per cent alumina, the balance being water (44 per cent), sulphuric acid (22 per cent), impurities (sand, gypsum, etc., 6 per cent) . It is therefore not what is commonly known as alum, but is hy- drous sulphate of alumina. To utilize it in mak- ing aluminum the manufacture should be car- ried on either at Silver City or Deming, as all the fluxes and reducing agents, excepting per- haps salt, exist in abundance in the neighbor- hood of Silver City, such as fluorspar, pyrites, copper ore, pyrolusite. Sulphate of alumina is now manufactured and sold in England, at $21.75 per ton of 2240 pounds, so that there would be nothing in shipping the Gila mineral to the seaboard.