you choose to call it, will be found in various forms. The last book I have to quote for it is Prony's Architecture Hydraulique i., Avertissement vii., and § 648, 649, 650. In the latter of which passages he observes that the first idea which occurs for raising water is to lift it in a bucket by hand. When the water lies too deep to be reached by hand, the bucket is suspended by a chain and let down over a pulley or windlass. If it be desired to raise a continued stream of water, the simplest means which offers itself to the mind is to attach to an endless chain or cord a number of pots or buckets, so disposed that, the chain being suspended on a lanthorn or wallower above, and plunged in water below, the buckets may descend and ascend alternately, filling themselves at bottom and emptying at a certain height above, so as to give a constant stream. Some years before the date of Mr. Evans' patent, a Mr. Martin of Caroline county in this State, constructed a drill-plough, in which he used the band of buckets for elevating the grain from the box into the funnel, which let them down into the furrow. He had bands with different sets of buckets adapted to the size of peas, of turnip seed, &c. I have used this machine for sowing Benni seed also, and propose to have a band of buckets for drilling Indian Corn, and another for wheat. Is it possible that in doing this I shall infringe Mr. Evans' patent? That I can be debarred of any use to which I might have applied my drill, when I bought it, by a patent issued after I bought it? These verbal descriptions, applying so exactly to Mr. Evans' elevators, and the drawings exhibited to the eye, flash conviction both on reason and the senses that there is nothing new in these elevators but their being strung together on a strap of leather. If this strap of leather be an invention, entitling the inventor to a patent right, it can only extend to the strap, and the use of the string of buckets must remain free to be connected by chains, ropes, a strap of hempen girthing, or any other substance except leather. But, indeed, Mr. Martin had before used the strap of leather. The screw of Archimedes is as ancient, at least, as the age of that mathematician, who died more than 2,000 years ago. Diodorus Siculus speaks of it, L. i., p. 21, and L. v., p. 217, of Stevens' edition of 1559, folio; and Vitruvius, xii. The cutting of its spiral worm into sections for conveying flour or grain, seems to have been an invention of Mr. Evans, and to be a fair subject of a patent right. But it cannot take away from others the use of Archimedes' screw with its perpetual spiral, for any purposes of which it is susceptible. The hopper-boy is an useful machine, and so far as I know, original.