Seeking alternatives to the difficult-to-work copper-nickel alloy, in June 1867 Longacre proposed that the five-cent piece be struck in aluminum. The new Mint director, Henry Linderman, objected to the proposal, stating that the price and supply of aluminum were as yet uncertain, and that the metal was too expensive to use in a minor coin. Numismatic historian Don Taxay, in his history of the United States Mint and its coins, noted that Linderman had proposed legislation increasing the proportion of nickel in the alloy to a third despite having earlier opposed the use of nickel in coins. Taxay suggested that Linderman was most likely influenced by Wharton and the metal's other advocates.