Section 4 of the English statute specifies but one way of making contracts within its scope enforceable, namely, by a written memorandum of the contract signed by the party to be charged, or his agent; and American statutes have followed the English model, though a few of them have enacted into statute the doctrine of part performance of contracts for the sale of real estate, a doctrine which, as established by courts of equity, may fairly be called a method of satisfying one clause of Section 4, without authority of statute. Section 17 of the English statute, however, which relates only to contracts for the sale of goods, provides several alternative modes of satisfaction; and wherever contracts for the sale of goods are covered by local statutes of frauds in the United States, these alternative possible methods of satisfaction are expressly permitted. So far as concerns a written memorandum, Sections 4 and 17 are alike; but the additional alternatives permissible by Section 17 for sales of goods alone, may be considered before consideration of the nature of the requirement of a memorandum.