The federal constitution indeed interdicts them in criminal cases only; but they are equally unjust in civil as in criminal cases, and the omission of a caution which would have been right, does not justify the doing what is wrong. Nor ought it to be presumed that the legislature meant to use a phrase in an unjustifiable sense, if by rules of construction it can be ever strained to what is just. The law books abound with similar instances of the care the judges take of the public integrity. Laws, moreover, abridging the natural right of the citizen, should be restrained by rigorous constructions within their narrowest limits. Your letter, however, points to a much broader question, whether what have received from Mr. Evans the new and proper name of Elevators, are of his invention. Because, if they are not, his patent gives him no right to obstruct others in the use of what they possessed before. I assume it is a Lemma, that it is the invention of the machine itself, which is to give a patent right, and not the application of it to any particular purpose, of which it is susceptible. If one person invents a knife convenient for pointing our pens, another cannot have a patent right for the same knife to point our pencils. A compass was invented for navigating the sea; another could not have a patent right for using it to survey land. A machine for threshing _wheat_ has been invented in Scotland; a second person cannot get a patent right for the same machine to thresh _oats_, a third _rye_, a fourth _peas_, a fifth _clover_, &c. A string of buckets is invented and used for raising water, ore, &c., can a second have a patent right to the same machine for raising wheat, a third oats, a fourth rye, a fifth peas, &c? The question then whether such a string of buckets was invented first by Oliver Evans, is a mere question of fact in mathematical history. Now, turning to such books only as I happen to possess, I find abundant proof that this simple machinery has been in use from time immemorial. Doctor Shaw, who visited Egypt and the Barbary coast in the years 1727-8-9, in the margin of his map of Egypt, gives us the figure of what he calls a Persian wheel, which is a string of round cups or buckets hanging on a pulley, over which they revolved, bringing up water from a well and delivering it into a trough above. He found this used at Cairo, in a well 264 feet deep, which the inhabitants believe to have been the work of the patriarch Joseph. Shaw's travels, 341, Oxford edition of 1738 in folio, and the Universal History, I. 416, speaking of the manner of watering the higher lands in Egypt, says, "formerly they made use of Archimedes's screw, thence named the Egyptian pump, but they now generally use wheels (wallowers) which carry a rope or chain of earthen pots holding about seven or eight quarts apiece, and draw the water from the canals. There are besides a vast number of wells in Egypt,