A very slight declivity suffices to give motion to water. Three inches per mile *n a smooth straight channel, gives a velocity ol about three mile per hour. ' The river Mag-dalena, in South America, running for one thousand miles between the ridges of the Andes, lalls only five hundred feet in all that distance. The Rio de la Plata has so gentle an ascent to the ocean, that in Paraguay, fifteen hundred miles from its mouth, large ships are seen, which have sailed against the current, all the way by the force of the wind alone. They were gradually lifted up that beautiful- ly inclined plane higher than the loftiest of spires,by the gentle influence of the soft windi but lor the gentle descent of waters, and the power of the wind, no vessel could sail up the gigantic De La Plata. Reported Officially for the Scientific American List of Patent Claims Issuded from the United Statei Patent Office FOR THE WEEK ENDING APRIL 12, 1853. HARROWS—By Wm. Berlin, of Berryville, Va.: I claim constructing a doable frame woik of Iron bars or straps of metal, and arranging and combining the two together by graduating bolts or adjustable screws and taps, by which means or contrivance, the lower frame can be elevated or depressed, and the teeh or tines, lengthenedor shortened in their drag or dip. STRING MATTRESSES—By Edwin L. Bushnell, of Poughkeepsie, N. Y.: I claim the mode or principle of securing the springs, by attaching the free extremity of each spring, to the terminal coil of the adjacent spring, so that they mutually support each other without the use of any inflexible frame of wood or other material, at the same time that in rolling or folding up the mattress, the outside ends of the springs are exposed or open, while the inside ends contract or close, and by which means any article, so constructed, will admit of being rolled or folded upon its self or compressed, substantially as described. SMUT MACHINES—By H. L. Fulton, of Chicago, 111.: I am aware that a flat plate on the side of the concave has been used ; this, therefore, I do not claim; but I claim the circular prismatic shaped brace and concentrator, arranged between each pair of revolving scouring plates, and secured fast to the inner periphery of the case for the purpose of concentrating the grain, and throwing it upon the second scouring plate, and thereby preventing its escape, before it is eff eotually cleaned from the first scouring plate, direotly to the discharge passage, as described. Also, in combination with the revolving dish shaped plates, or beaters, substantially as described, the prismatic ring, for the purpose of concentrating and directing the grain from one beater to the other as described. [See engraving page 369, Vol 7 Sci. Am ] MATOH SPLINT MACHINES—By Reuben P. Gus-tine, of Chicago, 111.:—I claim the combination of the reciprocating knife with a convex or protuberant rest, and feeding and holding mechanism, and the pressure roller, or any equivalent thereof, for the purpose described. COIN SAFE AND DETHOTOR—By J. J. Hatcher, of the District of Spring Garden, Pa.: I claim a coin safe, or receptaole for coin, consisting of the arrangement of the outer case, spring, with a pad, for holding the coin up against ttie top of the case and slide with its projection, or their equivalents, for forcing out the coin through the slot provided for the purpose, as described. RQSIN OIL—ByS.W. IIiwos.of Boston, Mass.: I do not claim th Arm OP Mat] of Apparatus set forth, irrespective of its use or particular application ; my claims being founded upon the invention or discovery, of improvements in the process of making roain oil by means of said apparatus, or any other equiva-! lent in principle. I Therefore I claim, first, in the process of making I rosin oil, charging and discharging the still, by I means substantially the same in principle or mode { of operation, as these set forth, whereby I save the j necessity of unlating, and prevent the incrustation I of the still. ! Second, 1 claim in the process of making rosin oil the separation of the oil from the more volatile products, at different and distinct points remote from the still, imtead of discharging them all together, a3 heretofore done, as set forth, by means of the series of recurved pipes, in combination with the Be-ries of condensers attached thereto, as set forth. SHINGL-B MACHINES—By Simon logersoll, of New York City: I claim the spring clipper,operated as ' described, in combination with the living knife, for ; the purpose of insuring the complete separation of the shingle from the block, and, at the same time, throwing it on the lower bed, in position to be carried to the dressing knives, by the next advance of the driver, as set forth HOT AIR REGISTERS—By E.A. Tuttle, of Wil-liatnsburgh. N. Y.: I claim constructing the leaves, of a register or ventilator, with projections on their surfaces, to form an ornamental open or fretwork, between the leaves, when they are turned with their edges uppermost or partially so, for the purpose of dispensing with the separate front or top plate of ornamental open work now employed On registers and ventilators. SEWING MACHINES—By Wm.H. Johnson, ofGran-ViUe, Mass.: I claim the use of a hollow, rotary clamp, as described, for holding and feeding cloth or other materials to be sewed, substantially as specified. MERCURY BATHS FOB DAQUKRREOTTPING—By B. F. Upton, of Bath, Me.: I claim combining with the mercury bath and the lamp for heating it, the sli- \ ding- tube and lever, or their mechanical equivalents, as ui.-:rihil, so that by the expansion of the bath the lever may be moved so as to elevate the slide tube on the wick, and thereby decrease the flame of the lamp and the heat thereof, or caused so to act as to maintain, or nearly so, equality of evaporation, as specified . WASHING MACHINES—By C. F. Wilgus, of West Troy, N. Y.: I claim the employment of the revolving feeding net cylinder, in combination with the two sets or circles of rollers, one set of said rollers being allowed to yield when the sack of clothes or other articles, is drawn round the net cylinder and between the said sets of rollers and made to spring back by means of the springs, which are connected to the rollers, the whole being construotedggarran-ged, and operated as described, and for the purpose of washing clothes and fulling and flocking cloths, as set forth. MANUFACTURING INDIA RUBBER AND GUTTA PER-CHA— By Chas. Goodyear & Robt. Haering, of New HaveQ) Ct. (assignors to Chas. Goodyear). Patented in England, March 4, 1851: We claim the art or method of manufacturing articles composed in part of caoutchouc, or other guma, susceptible of vulcanization, by heating or vulcanizing the same, when surrounded with and pressed upon, externally or internally by or moulded in pulverised soapstone, i Band, plaster, or other similar granular, pulverized, or porous matter, or jn moulds of plaster or other porous substance, as described. SOBETV BLANKB—By Cullen Whipple (assignor to the New England Screw Company), of Providence, R. I. Patented in England Nov. 30, 1852: I am aware that in machines for sharing the heads of screw blanks, the sharing cutter, whether moring on a slide or a rocker, has been moved to wards and from the black, obliquely to the axis of the blank, and therefore I do not claim, broadly, the moving of such cutter obliquely: but I claim the method of shaving the heads of screw blanks, by causing the cutter to approach the blank obliquely, and in line or nearly so, with the under side of the h@&d, whereby the use of a rest to support the blank against the pressure of the cutter is dispensed with, as bet forth.