We illustrate herewith a machine which hasbeen lately designed by an English firm, at therequest of H. LeeSmith, Esq., chiefengineer for thePunjaub Northern Railway, forscrewing downthe piles to beused in constructing bridges andflood openings onthat line of raH-way. Fig. 1 is aperspective, andFig. 2 a sectionalend viei'. Thismachine consistsof a wrought-ironunder - carr i agemounted up o nwheels of 5 ft. 6inch gage, andcarrying a vertical boiler at oneend. A strongcast-iron beam inthe center cai'riesa cylinder inwhich works aram, to the top of which a strong crossbeam is bolted which carriesthe machinery for operating on the piles. This consists of a horizontal steam engine bolted to the side of the crossbeam, and driving a pinion and train of spur and bevel wheels which impart motion to two large horizontal wheels carried in bearings at each end of the crossbeam. A friction clutch is carried in the center of each of these wheels, through the boss of which the shaft of the pile to be screwed is passed. The shafts are rolled with feathers or ribs on each side, which, passing through corresponding recesses or keyways formed in the boss of the friction clutch, form the means of imparting the rotary motion from the horizontal wheels to the piles. Steam is brought from the boiler through the center of the ram and cylinder which carries the crossbeam by means of a telescope joint, which allows the ram to be raised without interfering with the steam pip'e ; and a small donkey engine is provided which can pump from a tank situated between the frame , either into the boiler or into the cylinder under the ram which carries the crossbeam. When the machine is at work the crossbeam is held firmly by means of cotter bolts to the frame. The modus operandi is as follows: A temporary road being laid on the center line of the proposed structure, piles are pitched by passing the shafts through the wheels on each side of the machine, and keying them into the screws which are placed in a small hole excavated to receive them. The engine is then set to work, and the piles screwed down as far as possible. The cotters holding down the crossbeam are then removed, and it is raised by the donkey engine pumping into the cylinder in the center of the machine, and lifted off the piles. The machine is then moved forward to the center line of the next piles, and the operation takes place as before. Should a pile meet with any obstruction, or be found fast enough without screwing down to the estimated depth, it may be either unscrewed by reversing the engine, or the shaft may be cut off to the right hight, so that the crossbeam may be lilted clear, a slide rest and tool holder being provided, which is actuated by the horizontal wheels. At a trial of this machine, the Editor of E?2gineering recently witnessed two piles screwed into stiff clay 10 feet deep in 23 minutes, and withdrawn at the rate of3 ft. in 2tminutes with a mean pressure of 90 lbs. steam in the boiler ; and to test the efficiency of the cutting apparatus one pile was cut off in 29 minutes. The machine altogether does great credit to its designer, and from its great handiness and the rapidity with which it performs its work, it will no doubt recommend itself to those having to erect such structures as those on which it is intended to employ it. FIFTEEN HUNDRED DOLLARS, in cash, are to be paid by Munn & Co., February 10,1870, to the successful competitors for prizes. Send in the names as early as possible that we may know how large an edition to print at the commencement of the new volume. Competitors for cash prizes should write conspicuously "Prize List" on every list of names sent. Circulars and blanks for names sent on application. Those first in the field will stand the best chance. Acid Rivers The Rio Vinaigre, says the Boston Journal oj Ohemist1'y,in South Ametica, has its source nearly two miles above the level of the Bea on thevolcano named the "Purace." WiHumboldt was the first to ascertain that its waters contain free sul. phuric and muriatic acids. According to Boussin gault, this river empties into the Rio Cauca, into which it falls fro:tn a hight of about 400 feet, discharging daily 34,784 culjie meters of water, containing ; 37,611 kilgr.(more ;than 40 tuns) of ' strong. sulphuric acid, and 31,654 kilgr. (nearly 35 tuns)ofstrong mu I'iatic acid. No fish found in the Rio Cauca for more than ten miles below the point. ) where it receives these acid waters. In the island of Java there are sev eral small streams and lakes which contain free sulphuric and.muria-'tic acids ; and on the island of Sumatra there is a lake which contains free nitric acid. All these phenomena are the result of volcanic action. Test for the Quality of Soap To estimate the quantity of non-saponified fatty matter in soap, Dr. Boley gves the following formula : "Dry the soap at 100, in order to eliminate, as much as possible, any water it contains. 'l'reat the soap, after having been previously reduced to thin shavings, or powder, if possible, with rectified benzole, or petroleum naphtha. Boil the soap for several hours with this fluid placed in a retort, and take care to pour back into that veesel any of the hydrocarbon which distils over. Next filter the liquid, and evaporate on a water bath. 11-3 grms. of Marseilles soap (this is made with inferior kir ds of olive oil and soda) treated in this manner left a ressidue, on evaporation, weighing 0-145 grm., or 1*2 per cent ; this quantity consisted of the non-saponified fatty matter, and. a very small quantity of soap which had been dissolved. On igniting the residue just mentioned, it left 0'002 grm. of ash, equal to 0'18 per cent of the soap submitted to analysis. The Whitworth Metal When it is announced that this metal will withstand any shock or strain that can be brought to bear against it, it ought not to be wondered at that so extravagant and indefinite a statement meets with incredulity. There is, perhaps, little doubt that Mr. Whitworth has succeeded in producing iron and steel of superior strength by his method of subjecting these metals, while in a molten state, to enormous pressure, by which it is claimed all the air bubbles are ot rid of and the metal is rendered homogeneous. It will be slow work, however, convincing iron masters that the extravagant results claimed are to be relied upon. If they are even approximated, the proof can only be extended trials under varied circumstances of difficulty, and for ourselves, we had rather wait the test of time than to accept at present what we are asked t o believe in regard to it. A GOOD LIP-SALYE.—Equal parts of sweet lard and suet melted together, colored with alkanet root, and perfumed with essence of bergamot.