 [ N ] ew manufacture must have seven properties . First , it must be for twenty @-@ one years or under . Secondly , it must be granted to the first and true inventor . Thirdly , it must be of such manufactures , which any other at the making of such letters patent did not use ... Fourthly , the privilege must not be contrary to law ... Fifthly , nor mischievous to the state , by raising the prices of commodities at home . In every such new manufacture that deserves a privilege , there must be <unk> necessitas et <unk> <unk> . Sixthly , nor to the hurt of trade ... <unk> , nor generally inconvenient . 
