sentences:  The patent specifies that the metals be separately melted, then mixed, along with "sulphate of sodium or sulphate of potassium" in the amount of one part sulfate to one thousand parts metal.The alloy, in varying proportions (sometimes slightly out of these specifications), was used by the United States Mint to strike pattern dollars, sometimes called "metric dollars" (some were marked with "metric" in the coin design, while all had metal proportions and total coin weight as design features) from 1878 to 1880.Patterns of the same design were struck in other metals, including aluminum, copper, normal coin silver, lead, and white metal.