Our last visit to the Fair of the American Institute took us first among the pumps, of which there is a considerable variety displayed. We find no marked advance in this department of engineering since the exhibition of 1867, but we will briefly mention the most important of the pumps exhibited. The Woodward Steam Pump Manufacturing Co., of New York, exhibit one large single cylinder, and one large double cylinder steam pump with- several small ones of their manufacture, the Construction of which is too well known to our readers to render details necessary here. They also display a novel steam jpump called the “ Little Giant.” The pistons, both of steam cylinders and of pump cylinders, remain stationary while the cylinders travel. It is a double-acting pump—all the cylinders are vertical—and it occupies very little space. Its valves are 'cylindrical, and consequently balanced, and it is said to work very economically. Knowles&Sibley, of New York, exhibit some beautiful pumps, the workmanship of which is of a superior kind. The main steam valve of these pumps is carried over the center by means of an auxiliary valve of peculiar construction, the action of which is extremely delicate, rendering these pumps as suitable for boiler feeders, where a very slow motion is required, as for work requiring their fullest capacity. It will be unnecessary to dwell upon the special merits of these pumps as they are well known to all American engineers. The steam pumps shown by Geo. F. Blake&Co., of Boston, is also a good one, exhibiting many points' of merit, and excellently made. The steam valve is balanced, and it will start at any part of the stroke. The Emery Rotary Machine Co. exhibit Novarro's rotary pumps, the principle of which is the thrusting out and in of flat buckets by the alternate action of a fixed eccentric ring surrounding the shaft of the motor wheel and the case ; the wheel and fixed eccentric being concentric with each other but eccentric to the case. This pump is also a motor-wheel or a water-meter, by making it a propelled wheel instead of a propeller. J. H. A. Gericke, of Jersel City, N. J., exhibits his turbinate force pump, which is essentially a centrifugal pump. T. F. Rowland, of Greenpoint, Brooklyn, N. Y., also shows a powerful centrifugal pump, which is very simple in construction, and is so little liable to obstruction, that it may even be used for dredging. Philip S. Justice, of New York and Philadelphia, exhibits one of the pumping engines described and illustrated on page 33, current volume of the SCIENTIFIC AMERICAN, which is one of the novelties among this class of devices, and attracts much observation. It is making a favorable impression. Berhen's rotary engine and pump, exhibited by H. C. Dart&Co., of New York, is for many purposes doubtless as good a rotary pump as any present at the Fair, and it attracts much favorable comment. One of them is in operation as a boiler feeder, a kind of work which it does in a superior manner. The Niagara Steam-pump Works, of Brooklyn, N. Y., exhibit the well-known Niagara pump and engine, the arrangement of valves in which is admirable. The valves may be reached, all obstructions—if any chance to be present—removed, the valves replaced, and the pump set to running in a very short space of time . ' All that is necessary to get at the valves is the removal of a single nut. This pump has acquired a deservedly good reputation. Wm. D. Andrews&Bro., of New York, exhibittheir central- discl1arge centrifugal pump, and their patent improved antifriction pump. Important improvements have been added to the latter rElcently. The piston is balanced by a series ot holes in the piston itself, by which the pressure maybe equal iied ' on both sides of it, and the induction wing used formerly on these pumps is dispensed with. This pump is of great capacity and its operation excites much attention. From pumps to BLOWERS, which may be regarded as a species of air pumps, the transition is natural. There are only a few of these on exhibition. There are two kinds of fan blowers, each of which are great improvements over the original fan blower of Ericsson&Bathwaite, constructed in 1829. The most important of these is the multiplying pressure fan blower, invented and exhibited by P. Clark, of Rahway, N. J. All methods employed to attain increased pressure without increase of speed, except this, have proved unsuccessful to a greater or less degree. This blower is made up of a series of fan wheels all attached to a common shaft, and running at the same speed, but in different compartments, communicating only by an annular space surrounding the shaft, of sufficient capacity to permit the flow of air from the first compartment to the second, and so on. The rotary motion of the air acquired in each compartment is checked by a fixed turbinate arrangement of curved buckets, which change the © 1869 SCIENTIFIC AMERICAN, INC. 282 [OCTOBER 30, 1869. direction of the current and conduct it through tie annular space above alluded to, when 1,he next fan in order takes it and gives it additional pressure, and so on to the end of the series. Water gages attached to each compartment show that the pressure is uniformly increased in each compartment. It is thus the required pressure may be obtained without excessive speed. This blower, as being one of the few novelties of the machinery department, attracts much attention Irom mechanical visitors to the Fair. The pressure blower exhibited by B. F. Sturtevant, of Boston, Mass., is also a good blower, running without great noise and performing good work. This blower has been before the public so long, and is so favorably known that we need not dwell upon its details. A machine of an entirely different class is Root's patent force-blast rotary blower, exhibited by S. S. Townsend, ofNew York, the construction of which can hardly be explained without diagrams. It gets up a strong blast with slow speed, the air being impelled hy absolute pressure. The weight of the moving parts is light, they being composed chiefly of wood, and very little power is absorbed in friction. There are no valves, and the parts of the machine are very few in number. The same principle is applied to hand blowers, of which there is one on exhibition— very convenient and effective substitute for the old-time blacksmith's bellows for forges. Besides the pumps mentioned, exhibited by “Wm. D. Andrews&Bro., of New York, that firm also exhibit their patr ent OSCILLATING ENGINES, by which their pumps are operated. They also show one of their friction grooved hoisting machines, with oscillating cylinder and direct connection of the piston rod and crank. Motion is, in this machine, communicated to a wheel and axle by grooved friction pulleys. It therefore runs without noise, and the speed is perfectly controlled. A novelty ia STEAM GENERATORS, 'hot on exhibition at our previous visit, is exhibited by Thomas Mitchell, of Albany, N. Y. It is a cylinder of wrought iron with welded joints, into which water is thrown by a feed pump ; the same pump operating through a worm gear to slowly rotate the cylinder in the furnace where it is suspended upon two journals, one at either end ot the furnace. The design is to only throw water into the revolving generator, as wanted, tomake steam. The steam is generated under very high pressure. The water is injected through a core pipe in one of the journals which extends longitudinally through the axis of the cylinder, and is perforated at intervals throughout its length. The water is thus subdivided into small jets, which the heat of the cylinder converts into steam instantaneously. In one corner of the floor devoted to tl 1 e exhibition of machinery stands two beautiful machines displayed by S. R. Krom, of New York, one of which is an ore crusher and the other a dry ore concentrator ; both these machines exhibit a degree of mechanical and inventive skill highly creditable to their inventor. The crusher munches up large lumps of the hardest ores, with as much ease as a boy could crack a hazel nut, while the concentrator separates the ores from the gangue with great rapidity and certainty. The prominent feature of this machine is'the use of intermittent puffs of air, which renders available whatever difference there may be in the specific gravity of the ore and its gangue. The construction of the machine is based upon sound scientific prineiples, and will well repay inspection. In the DEPARTMENT OF INTERCOMMUNICATION. there is very little worthy of mention. There is, however, a model of a turn-table exhibited by James B. Kelly, of KeIl- dallville, Ind., which turns on car wheels of the ordinary constructions, rolling between concentric tracks on the under side of the table and corresponding tracks upon which the wheels rest. The wheels are kept at their proper distances by radial shafts upon which they play almost without friction, as these shafts bear no part of the load. The model works with remarkable ease, and we judge the principle might be advantageously applied to drawbridges, locomotive turn-tables, etc. A novelty in this department are the PAPER BOATS, exhibited by A. Waters, of Troy, N. Y. They are beautifully finished and astonishingly light. The largest one exhibited, capable of carrying 170 lbs., only weighs 32-! lbs. These boats attract much attention. 'Ve take this occasion to notice a STEAM ]'IRE ENGINE exhibited by Cole Brothers, of Pawtucket, R. I. It is finished in a high style of art, and has some peculiarities of construction worthy of note. The piston rod is forged solid, by which cramping of the link block is obviated. The pump is always charged from the outlet by means of the siphon form of the suction pipe. These engines are guaranteed to draw water twenty-nine feet. They are compact and built to combine strength with lightness, so far as this is practicable. Near this fire engine stands an ELECTROMAGNETIC ENGINE, in which there is no new principle displayed, but the application of which to the driving of sewing machines attracts a great deal of attention. The motion is uniform and sufficiently strong for the purpose, and we were told that the expense of maintaining the battery was only ten cents per day. In passing from the builtng we notice one of the best things we have seen at this Fair, namely, Poulson's patent lazy-tongs SHUTTER BLIND AND AWNING, niade entirely of metal, and worked ftom th e inrn'de hy a, crank. When open they are entirely out of sight, and when closed they are burglar and fire proof. They can be adjusted to admit light and air and exclude the sun. The awnin gs are supported by brackets from the wall, and are adjusted in the same manner as the blinds. They are simple in construction, not liable to get out of order, not materially more expensive than the ordinary awnings and fixtures, and in our opinion far superior to any thing of the kind hitherto used.