Chapter V: Front Matter (5)

One of the grand necessities of the Prospect Park, Brooklyn, N.Y., that of providing for a continual supply of water for all the purposes of the Park developed itself, as the Commissioners progressed with their stupendous undertaking. Mr. Stranahan, the President of the Board, after carefully weighing the cost, the practicability, and importance of having an independent water supply for the Park, advised the Commissioners of the plan which had suggested itself, and the calculations which had been made by the engineers relative to the project, and the work was commenced, the first idea being to secure at least a partial supply of water by means of a well constructed in the Park. The subject was thus treated in the last annual report of Mr. C.C. Martin, the engineer in charge:

"This well has been located on the south side of Lookout Hill, near the lake, and work was commenced upon it late in the season. After a careful consideration of various methods for sinking the well, it was decided to build the wall and then to excavate the material from within, trusting to the weight of the wall to force it down. Sixteen feet of the wall were laid securely bolted together, before the excavation was commenced. A derrick with a boom fifty-five feet in length was set up near the wall, so that the sweep of the boom commanded the interior of it. Iron buckets containing fourteen cubic feet each were obtained, and a six-horse power hoisting engine purchased. With these appliances the excavation was commenced, and carried on with slight interruption until the work was suspended on account of the frost."

The well is now completed, and is one of the most important features of the Park. It is worthy to rank as a feat of engineering skill with, any of the great works of modern times. The Commissioners decided to put its powers to the test yesterday afternoon, but owing to the unpropitious weather of the forenoon the trial was postponed. Nevertheless, Commissioners Stranahan, Fiske, and Haynes, with Mr. Martin, engineer in charge, and Mr. John Y. Culyer, his assistant, were at the well. During the last summer some difficulties were encountered in the sinking of the wall, which were set down by superficial observers as the utter failure of the enterprise. Mr. Stranahan received but little encouragement from his fellow Commissioners, some of whom had never seen greater works of engineering than the construction of street sewers. He assumed the responsibility of seeing the work through, feeling that the whole thing depended entirely upon the ability of the engineers, in which he had abundant faith. All obstacles were surmounted; the work proceeded and the well is now finished, and so far as is known, is understood to be the largest one in the world.

The outer wall is fifty feet in diameter, two feet thick, and fifty-four feet high. The inner curb, or wall, is thirty-five feet in diameter and two feet thick, having a depth of ten feet. The masonry, as seen from the top of the structure, is a marvel of neatness and solidity. The water surface in the well is thirteen feet above high-tide level, and the depth of water in the well is fourteen feet. The pump foundations are entirely independent of the walls. This plan was adopted so as to obviate any possible difficulty which might arise from displacement. The pump is the Worthington patent, and, with a pressure of forty pounds, is capable of raising one million gallons of water every twenty-four hours a height of 176 feet, and is competent to a lift of 180 feet.

The boiler house is a neat, pressed-brick structure trimmed with Ohio stone, standing on the surface near the mouth of the well. The interior of the well is reached by a spiral stairway built in the wall, and commencing in the boiler house. In this way the engineer is able to reach the pump. It is a fact worthy of notice in connection with the construction of the wall, or rather the sinking of it, that the outer wall rests upon four feet of wooden cribwork, two feet thick, and having an iron shield. The inner wall is built upon a similar crib only two feet deep, also shielded with iron.

The Commissioners were led to the construction of this well in presence of the danger at any time of some accident taking place in connection with the Brooklyn Water Works which would render it necessary for the Water Board to cut off the Park supply so as to secure the citizens from suffering. This well has more than the necessary capacity to supply the Park abundantly with water, yielding most when most is needed. This is established by the discovery that the time of drought from which the well is, or may be, likely to suffer, occurs in the Fall. Besides these facts, it further appears that in order to furnish the supply of water to the Park the Water Board would have to go through the process of pumping their water twice to convey it to the required elevation, equal to 225 feet from its original level.

The work of the well will be to supply the pools at an elevation of 133 feet. From the pools the water is conducted to the lake. Besides this, there is an independent connection with the lake by which, as necessity may suggest, the water can be directed to the lake, a lift of only seventy feet. The lake, when completed, will occupy an area of fifty acres, which will be kept continually supplied with fresh water, the arrangements being such, or to be such, as will insure a permanent change of water, and prevent any of the evils that may arise from stagnancy. The well is fed from the earth, consisting of a circuit of two miles, with a fall of five feet to the mile. For this reason it does not appear easy to exhaust the supply, as when the water is pumped out to four or five feet from the surface of the well it is replaced at a rate equal to the demand. Every allowance has been made for evaporation from the lake and pools, and the supply is regarded as inexhaustible. Another important fact here suggests itself; that is, that sufficient rain falls during the season in the area of two miles around the well to make the supply perennial. The Prospect Park well is a credit to Brooklyn.--_New York Times_.

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PAPER FOR BUILDING.

Our readers will find in another column an advertisement of this new building material which is now attracting much attention in the West, and of which we have received very favorable reports. It has been recently tested in Chicago with the result we are informed of fully establishing its utility. It is said that a house twenty-two feet long, sixteen wide, and fourteen high, can be covered on the outside for less than $9; and a house thirty-six feet by twenty-two, and twenty feet high, for $20. The building can be done at any season, and can be finished with great speed, and there are said to be numerous other advantages connected with the use of the paper. It differs from ordinary paper in consistency, compactness and solidity. In the manufacture it is subjected to a pressure of hundreds of tuns, which squeezes out the liquid matter, leaving a substance of the right thickness. It is said to be proof against damp and gnawing of vermin, and it being an excellent non-conductor of heat, must make a warm dwelling in winter and a cool one in summer. It is used in the place of plastering for inside walls.

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The Prussian Government has military maps of every foot of its territory so complete that every hill, ravine, brooklet, field, and forest is delineated with perfect accuracy. It is a common boast of Prussian military men, that within the space of eight days 848,000 men can be concentrated to the defense of any single point within the kingdom, and every man of them will be a trained and well-equipped soldier.

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Improved Muzzle-Pivoting Gun.

We are indebted for the following able description and criticism of this Prussian gun to our able contemporary, _The Engineer_.

Viewed as a piece of mechanism, nothing can well be more beautiful in mutual adaptation of parts to the fulfillment of given and rather recondite movements, and in point of execution, than this muzzle-pivoting arrangement of Herr Gruson's; but having said this we are compelled to add, as impartial engineering critics, that it is nothing more.

A very few words of description, aided by the very clear engraving annexed, will suffice to make the arrangement plain to every mechanical reader. The entire structure is metallic, chiefly of cast iron or of steel. Upon the platform of the casemate, or deck of the ship, or turret, is laid the heavy bed or traverse plate, cast hollow in iron, holding the vertical pivot at its forward end, on which the gun slide traverses in azimuth, and at its rear end the segment plate, bolted down and separately adjustable as to position upon the bedplate. The slide is also a ponderous hollow casting, the upper surfaces of which, on which the gun carriage runs forward or recoils, are curvilinear in a vertical plane, so that the inclination to the horizon is greatest at the rear end. At the rear end of the slide it traverses upon two heavy cast-iron turned conical rollers, which are geared together and actuated by the winch handle and spur gear, seen in our engraving; by these the slide is practically held fast in any position on the bedplate. The gun itself--in the model, a steel breech-loader, on the Prussian regulation system, very slightly modified--is sustained between two high and ponderous cheek plates of cast iron, which constitute the sides of the carriage, and which are connected together strongly at the lower edges by a heavy base or bottom plate, and at the top by two light cross distance bolts. The muzzle and breech extremities of the piece project well beyond those cheeks. Along the bottom of the trough of the carriage, directly under the gun, lies a nearly horizontal hydraulic press cylinder, the pump and handle actuating which are seen in the figures to the proper left of the gun, and the supply of water for which is contained in the hollow bottom of the carriage. On each side cheek of the carriage is formed, by curved planing, a circular segmental race, opening inward or toward each other, rectangular in cross section and into each of which is fitted a segmental block just filling it up, and occupying a portion of its length so as to slide easily up or downward through the whole range of the arc or segment.

The center point of the length of each of those blocks carries one side of the gun, which is connected also with the two heavy radius bars seen outside the cheeks, and pivoted close to the segment races on the outside, and with a system of link work between the gun itself and the crosshead of the ram of the hydraulic cylinder, which gives motion to the gun in elevation or depression, through a vertical arc, the imaginary center of which, and of the segments of the side cheeks, is situated in the horizontal diameter across the muzzle of the gun. This is in brief the muzzle-pivoting part of the arrangement, of which, were it worth while to go into its details, we should need some further diagrams to make it quite clear. Nor is it worth while to go into the description of various minor points of refinement about the gun mounting, such as the very exposed long tangent scale seen in the figure, by which the elevation or depression is read off, nor the still more exposed and rather ricketty arrangement by which the rear sight is arranged to rise and fall with the gun, and allowance for dispart avoided. The recoil of the gun is resisted through and by the segment blocks in the side cheeks, and by the heavy radius bars, etc., and thus transferred to the carriage itself. This moves upon four eccentro-concentric rollers, in all respects identical with those brought before the Ordnance Select Committee of Woolwich by Mr. Mallet, in 1858--then rejected, after some time adopted, and brought into use in our own service, where they are now universal, and from which they have been adopted into every artillery in the world, and, we understand, without the slightest recognition of the inventor's rights. On the axle of each of these rollers is keyed a circular eccentric cam plate, those at the same side being connected together by a linking bar so as to move in concert. Adjustable tripping plates attached to the sides of the slide, are so arranged that when the loaded gun has been run forward its carriage base rests hard down, with its full weight upon the top faces of the slide, and thus the recoil is made under the full resistance due to the friction of the entire load. Arrived at the highest point, it rests there until loaded. The cam plates being then given a slight motion of rotation by the help of socket levers--the rectangular projections to be received by which are seen on the top edges of the cam plates in the figure--the carriage, by its own commenced descent, gets again upon its rollers, and runs forward upon these at once into firing position. The two elevated horns which are seen standing up at the rear part of the slide above the roller frame are designed to receive the thump of the two short buffer-blocks--seen at the rear part of each carriage cheek--in the event of the recoil not being wholly expended in raising the weight of gun and carriage, etc., along the curved racers of the slide. These buffer-blocks bear against plugs of vulcanized india-rubber secured in the bottoms of the buffer cylinders.

We have thus, though very briefly, described the whole of this mounting. As a carefully thought out and elaborated piece of elegant mechanical complication Herr Gruson's muzzle-pivoting carriage attracted much attention at Paris, in 1867, and its merits were regarded as great by those whose thoughts went little further perhaps. We should have been glad had it been in our power to have joined in its praise. We are, however, obliged honestly to say that, however highly creditable to its designer as an ingenious and capable mechanism, it shows that he has never realized to himself as a practical artillerist the primary, most absolute, and indispensable conditions of construction for a serviceable muzzle-pivoting gun for either land or sea service.

As to the general merits, or general conditions, of muzzle-pivoting, however, once in doubt at first, these are admitted now by all; and the latter resolve themselves almost into this--that system of muzzle-pivoting must be best which, while preserving the essential point of leaving the muzzle of the gun free of any direct attachment, i.e., with an imaginary, not an actual, pivot of vertical arc motion, shall be _the simplest possible_ in its parts, have the least details, the fewest parts capable of being struck by splinters or shot, and all its parts of such materials and character as to receive the smallest amount of injury if so struck. In every one of these aspects Herr Gruson's mounting is at fault. With parts and movements far more ingeniously adapted than those of the crude and unskillfully designed muzzle-pivoting carriages of Captain Heathorn, also exhibited at Paris, and much exhibited and exposed since, the Gruson mounting is even more complicated, expensive, and liable to injury of every sort to which a gun carriage can be conceived liable. We may even venture to affirm that ponderous as was the mass of cast iron, etc., in the Paris model carrying only a 12-pounder gun, were it all enlarged in such ratio as might appear to suit for a 10-inch 25-tun rifled gun of the British type, the almost proverbial relations, between weight, velocity of impulse, and brittleness of cast iron, would show themselves, in the whole machine going to pieces within a very few rounds.

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Stock Feeding by Clock Work.

Mr. F. B. Robinson, of North Haven, Conn., has invented a very neat arrangement, whereby horses or stock can be fed at any time required with certainty and without personal attention at the time of feeding. His invention consists of a hopper with a drop bottom in which the provender is placed. A latch secures the drop bottom, the latch engaging with a spring catch. A simple arrangement of clock work on the principle of the alarm clock, may be set to release the spring at any hour or minute desired, when the drop falls and the provender falls through a chute into the feeding trough. This invention may be adapted to feeding any number of horses or cattle, only one clock being required. We regard the invention as one of much value. By its use much neglect of careless attendants may be obviated, and a farmer without help, might leave home for an evening's entertainment, or absent himself on business, without fear that his stock would suffer. Besides being so convenient the cost of the apparatus is a mere bagatelle.

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Milk, and What Comes of It.

Orange County has long been a laud flowing with milk and--butter. Three or four of these most beautiful autumn days were spent by us, says a writer in _Harper's Weekly_, among the farmers which are supposed to butter our New York city bread, and qualify our tea and coffee. Recent mechanical improvements have taken away much of the traditional romance of the farm, but, on the whole, the loss is more than made up by the gain of perfect system and wonderful adaptation. Instead of four or five cows, known by such names as Brindle, Bess, and Sukey, milked by rosy-cheeked maidens, we have now droves of fifty or a hundred, milked by men, who know them only as "good" or "poor milkers."

In some fine farms a large and luxuriant pasture, with running brooks and border of woodlands, affords, with the herd feeding in it, a beautiful picture; and the substantial barns constructed to keep the cattle comfortably cool in summer and warm in winter, with ample drinking troughs and stalls for fastening up at night, are indicative of the good shelter at hand when winter storms drive the cows indoors. To the farmyards the cows are brought night and morning, in summer, to be milked. The strained milk is put into large cans holding forty quarts, such as the milkmen use in distributing it through the city. These cans are then put into tanks made in some cool running stream, where the water comes nearly to the top of the can. Frequent stirring is necessary until the animal heat is quite gone. The milk is then fit to be sent to the cars. This process can never safely be omitted for, paradoxical though it may seem, milk is "fresher" and sweeter when it reaches the consumer if it is delayed at the farm for at least twelve hours. Even in hot weather, it is more certain to keep sweet when twenty-four or thirty-six hours elapse between the milking and the using in the city.

There has been much discussion as to the best means of cooling milk for market, and patent pails have been tried in which the milk passes directly from the cow through small, coiled tubes surrounded by ice. But this rapid cooling does not work well, and practical experience indicates that the old simple process is the best. Every well-appointed farm must have, therefore, a cool and unfailing stream of water. There are two such streams in one of the farms we visited. One passes through the barn, furnishing drinking troughs for the cattle, and a tank for cooling milk in winter. The other, running through the pasture, supplies a trout-breeding pond, and furnishes a tank for summer use. In a little hut under the trees, the milk cans are kept in a stream, which even the severe drought of last summer did not dry, nor the heat raise to a temperature of 60°.

We are assured most positively that none of the spring water finds its way over the mouth of the can into the milk. Its dilution, of which there is so much just complaint, must be done, if at all, in the city, for the wholesale buyer is said to have such means of testing the milk as effectually protects him against the farmer. May the man be busy at work who is to give each family such a protection. We have heard it said that one end of a small piece of common tape placed in a pan of milk will carry from it all the water into another vessel in which the other end of the tape should be placed; but we have never found this a safe test.

Strange to say, no butter is made on these large milk farms. The supply for the family is obtained from market, or, more rarely, from a neighbor who churns all his milk for the accommodation of those who send all theirs to the city. Our notions of the way to make butter were decidedly overturned on going to such a dairy. No setting of the milk in shallow pans for cream to rise; no skimming and putting away in jars until "churning day," when the thick cream was agitated by a strong arm until the butter came, then worked and salted. Instead, there is a daily pouring of the unskimmed soured milk into a common churn, perhaps somewhat larger than ordinary. The dasher is fastened to a shaft, which is moved by a crank. The crank is turned by means of a nearly horizontal wheel some eight or ten feet in diameter, which is kept in motion by a dog, sheep, or calf standing on it, something after the manner of the old tread-mill.

When taken from the churn, the butter is worked by hand as of old. The farmer with whom we have talked said he was about determined to send his milk to the creamery, since butter-making made it so hard for the women. Surely woman is less a drudge than she used to be. If, after being relieved from the labor of churning, the remaining working of the butter is considered too hard for the farmer's wife, the day of a woman's redemption must be near at hand.

Only one butter farm, have we been able to find, and not enough is made there to supply the immediate neighborhood. Where, then, does all the Orange county butter come from? Mostly from the West. Farmers buy from the vicinity of the Alleghenies, and even further west, large quantities, which they sell in the original packages or repack in pails. Since railroads have become so numerous, New York drinks up all the milk in Orange county, and must butter her bread elsewhere.

The largest institution for the disposition of milk is the Creamery, which is, in other words, a cheese factory. Here is brought the milk which the farmers themselves are unable properly to prepare for market, for want of cool springs or sufficient help. Received here, it is placed in deep but narrow tin pails holding twelve or fourteen quartz. These are floated in large tanks of water. From these pails the cream is carefully taken and sent to market. The skimmed milk is then placed in a large vat and heated, by means of steam pipes to about 80°. Then the rennet is put in. From twenty to thirty minutes suffices for curdling, and the mass is then stirred to separate the curd from the whey. After which it is heated still more; and then the whey, passing off through a strainer, goes to feed hogs, while the curd remains in the vat, to be salted and worked before putting into the presses. In two or three hours the curds become hard enough for the canvas to be put upon them ready for the shelves. Very carefully they must then be watched, lest the fly lying in wait for them makes in them a snug house for her family. Greasing and turning must be a daily labor, and some weeks must pass before they are sufficiently cured for market.

For the benefit of city consumers, who are paying ten and twelve cents a quart for milk, from a tenth to a quarter of which is not infrequently pure Croton, we may add that the highest price the farmer ever gets for his milk is seven cents a quart; and he sometimes sells it for as low as two cents and a half. Our friends, the milkmen, have, therefore, it will be seen, a pretty good margin for freight and profit.

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Improved Hay Elevator.

The method most generally used for elevating hay is evidently not the most economical application of the power of horses for the accomplishment of the purpose desired. The tackle involves a great deal of friction, and as the quantity which can be thus raised at once is, probably, on the average, not more than from 150 to 200 lbs, much more time is employed in re-adjusting the fork, than would be the case if a larger quantity were elevated.

The invention under consideration supplies a means whereby it is claimed hay may be unloaded with far greater facility than heretofore, with less labor to the team and with fewer hands than are at present employed.

A primary gear wheel is propelled horizontally by a lever worked by a horse. The primary gear impels a pinion keyed to the shaft of a windlass, upon which is wound the elevating rope, whenever the clutch, A, is made to operate through the cord and lever, B. This cord runs over a pulley on the under side the wood framework at C, and its further end may be held in the hand of the workman on the hay load, who, when he has properly adjusted the fork, pulls the cord which operates the clutch, and the "fork-full" of hay is at once elevated. The cylinder of the windlass, not being keyed to the shaft, only operates when the clutch is closed by the cord.

The horse, or horses which furnish power to the machine, may, therefore, keep on traveling in the same direction, and no time is lost in stopping and backing, as in the method in general use.

There is no doubt but that this is a cheap, durable, and desirable machine, and one that can be used to great advantage, not only for the elevation of hay, but for many other purposes. We think it would be found a decided improvement in discharging cargoes of coal from barges, and for handling coal in storage yards.

The inventor claims that twice as much hay can be raised in a given time by its use, as can be done by the old method; and it dispenses with one hand at the barn or stack.

A coupling at D, enables attachments to be made, which extend the usefulness of the machine very much. It may be used as a power for driving wood saws, cutting fuel, thrashing, and other work where a simple horse power is desirable.

Address for further information, Wm. Derr, Tiffin, Ohio.

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COMPETITORS FOR PRIZES.--The interest that our friends have taken in obtaining additional names to send with their own subscriptions to the SCIENTIFIC AMERICAN for the coming year, is without a parallel. The clubs sent by competitors for the cash prizes are not so many or so large as we expected, but the number of applicants for the steel plate engraving exceeds our expectation.

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The Emperor of France is said to be interested in the art of flying and to have given money to fledge some inventions.

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IMPROVEMENT IN LAMP WICKS.

Our engravings show a novel substitute for the cotton lamp wick. The wick, two forms of which are shown in Figs. 1 and 2, are made of glass, and are filled preferably with pulverized gypsum, although any finely-ground stone, mineral, or metal may be employed. The bottom of the glass tube is closed by wire gauze, or other suitable strainer, through which the fluid flows; and is carried by the capillary attraction of the pounded material to the top of the wick.

Thus a permanent wick is obtained, which may be employed with any form of lamp, and will last for an indefinite time. It may also be used in connection with an open cup, which the inventor terms a poor man's lamp. A perforated card is laid upon the top of the cup or tumbler as a support to the wick.

It may be used either with or without a chimney, and it is claimed that with good kerosene oil it is perfectly safe, and consumes less of it, while it may be also used as a candle.

Patented through the Scientific American Patent Agency, September 14, 1869, by Edward D. Boyd, of Helena, Ark.

Address for rights, etc., the patentee, as above, or Jos. P. Branch, 277 Fulton street, Brooklyn, N.Y.

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Great Transformation.

Seven years ago, says the Port Said correspondence of the London _News_, there was nothing to distinguish Ismailla or the smiling lake before you from the rest of the desert, and all was sand. It is the canal which has raised up the numerous handsome villas and fine gardens. Fresh water is all that is needed to turn the arid desert into a fruitful soil; and the supply of this is provided by the subsidary canal which the company has formed side by side with that broad salt one which now unites two worlds. Wonderful stories are told of the productiveness of the gardens, and a walk through any of those belonging to the leading officials stationed at Ismailla is to verify them all. Vines with large bunches of grapes pendent from their branches; orange trees with green fruit just showing a golden tint; ivy, roses, geraniums from England, and an endless variety of rich tropical plants are all flourishing. In the centre of the town is a square with trees and a building clothed with rich creepers in its midst. Everything here looks French. A handsome boulevard runs down to the point of embarkation, the streets and squares are on the true Parisian model, and there are _cafes_, billiard rooms, and _cafe chantants_ which might easily belong to Nantes or Lyons. There are of course huge gaps where the houses and shops will be; the roads are, many of them, still of sand; camels draw carts, and generally pervade the place in long strings; but with all this you are kept in a state of wonder during your stay at Ismailla at the marvelous conversion which has taken, place under your eyes.

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American agricultural implements are highly praised in newspaper reports of the Metropolitan Cattle Show, held recently in London.

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Moore's Rural New Yorker

For Dec. 25 contains a splendid full page Engraving of the PRIZE FOWLS at the recent State Poultry Show--the Best Poultry Picture ever given in an American newspaper.--Also, a magnificent CHRISTMAS PICTURE, and other fine Illustrations. For sale by all Newsdealers; price 8 cents. See advertisement of RURAL in this paper.

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BUSINESS AND PERSONAL.

_The Charge for Insertion under this head is One Dollar a Line. If the Notices exceed Four Lines, One Dollar and a Half per line will be charged._

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To ascertain where there will be a demand for new machinery or manufacturers' supplies read Boston Commercial Bulletin's manufacturing news of the United States. Terms, $4.00 a year.

Ties, timber, and lumber seasoned by steam, without a building. Costs $2, worth $20 per M. Stops eramacausis. H.G. Bulkley, N.Y.

Wanted--Light Machinery or Articles to Manufacture. Work done in a neat, prompt manner. Address W.E. Bradner & Co., 13 Mulberry st., Newark, N.J.

Pyrites wanted--Containing Gold, Silver, or Copper. Address A.G. Hunter, Jackson, Mich.

Those wishing articles of metal or light machinery manufactured, will find it for their interest to address J.B. Heald, Milford, N.H.

One horizontal stationary steam engine, with variable cut-off, 60-H.P.; one plain do., 25-H.P.; one do., 20-H.P.; one Portable 12-H.P., on hand and for sale low. Albertson & Douglass Machine Co., New London, Conn.

For sale cheap--Good 2d-hand plate iron. 50 plates 3-8 thick, 42 inches wide, 120 inches long. Been used 3 months for a floor. Price 3 cents per lb. Address box 1352, Norwich, Conn.

The head draftsman of a locomotive works, just closed, desires another engagement. Familiar with stationary, marine, or locomotive machinery. Unexceptionable references. Watkins, 13 Dutch st., N.Y.

Wanted--Iron Planer about 4 ft., describe same and price, Geo. S. Grier, Milford, Del.

Wanted--Best Water Filter for Household purposes. Frank Alexander, Box 3769, New York.

A Brick Machine wanted. Address A. Hansen, Sumter, S.C.

For Sale for want of use--A 3-Horse portable steam engine and boiler, in perfect running order. Address B.S. Nichols & Co., Burlington, Vt.

Patent Rights bought and sold by R.T. Bradley & Co., 131 Fourth st., Cincinnati, Ohio.

Peck's patent drop press. For circulars, address the sole manufacturers, Milo Peck & Co, New Haven, Ct.

Every wheelwright and blacksmith should have one of Dinsmore's Tire Shrinkers. Send for circular to R.H. Allen & Co., Postoffice Box 376, New York.

For Small Engine Lathes, with foot-power, Hand Lathes, Bolt or Terret Cutters, Planers, etc., address W.E. Bradner & Co., Newark, N.J

Aneroid Barometers made to order, repaired, rated, for sale and exchange, by C. Grieshaber, 107 Clinton St., New York.

Foundery and Machine Business.--Experience with some capital, wants an engagement. South or West preferred. Address Box E.E., Catskill, N.Y.

Foreman in a Machine Shop--A person having ten years experience in that capacity is desirous of forming a new engagement. Address, with particulars, Postoffice Box 119, La Crosse, Wis.

Makers of Pipe Cutting and Tapping and Screwing Machines send circulars, without delay, to Forest City Pipe works, Cleveland, O.

For Best Spring-bed Bottoms address S.C. Jennings, Wautoma, Wis.

Parties having patents or patent goods to sell, send for The National, Buffalo, N.Y., $1 per year, 10c. single copy.

Back Nos., Vols., and Sets of Scientific American for sale. Address Theo. Tusch, No. 37 Park Row, New York.

Mineral Collections--50 selected specimens, including gold and silver ores, $15. Orders executed on receipt of the amount. L. & J Feuchtwanger, Chemists, 55 Cedar st., New York.

The Babcock & Wilcox Steam Engine received the First Premium for the Most Perfect Automatic Expansion Valve Gear, at the late Exhibition of the American Institute. Babcock, Wilcox & Co., 44 Cortlandt st., New York.

For best quality Gray Iron Small Castings, plain and fancy Apply to the Whitneyville Foundery, near New Haven, Conn.

Keuffel & Esser, 71 Nassau st., N.Y., the best place to get 1st-class Drawing Materials, Swiss Instruments, and Rubber Triangles and Curves.

Foot Lathes--E.P. Ryder's improved--220 Center st., N.Y.

Those wanting latest improved Hub and Spoke Machinery, address Kettenring, Strong & Lauster, Defiance, Ohio.

For tinmans' tools, presses, etc., apply to Mays & Bliss, Brooklyn, N.Y.

Mill-stone dressing diamond machine, simple, effective, durable. Also, Glazier's diamonds. John Dickinson, 64 Nassau st., New York.

Send 3-cent stamp for a circular on the uses of Soluble Glass, or Silicates of Soda and Potash. Manufactured by L. & J.W. Feuchtwanger, Chemists and Drug Importers, 55 Cedar st., New York.

Glynn's Anti-Incrustator for Steam Boiler--The only reliable preventative. No foaming, and does not attack metals of boiler. Liberal terms to Agents. C.D. Fredricks, 587 Broadway, New York.

Cold Rolled--Shafting, piston rods, pump rods, Collins pat. double compression couplings, manufactured by Jones & Laughlins, Pittsburgh, Pa.

For solid wrought-iron beams, etc., see advertisement. Address Union Iron Mille, Pittsburgh, Pa., for lithograph, etc.

Machinists, boiler makers, tinners, and workers of sheet metals read advertisement of the Parker Power Presses.

Diamond carbon, formed into wedge or other shapes for pointing and edging tools or cutters for drilling and working stone, etc. Send stamp for circular. John Dickinson, 64 Nassau st., New York.

The paper that meets the eye of manufacturers throughout the United States--Boston Bulletin, $4.00 a year. Advertisements 17c. a line.

Winans' boiler powder, 11 Wall st., N.Y., removes Incrustations without injury or foaming; 12 years in use. Beware of Imitations.

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ANSWERS TO CORRESPONDENTS.

_Correspondents who expect to receive answers to their letters must, in all cases, sign their names. We have a right to know those who seek information from us; besides, as sometimes happens we may prefer to address correspondents by mail.

SPECIAL NOTE.--This column is designed for the general interest and instruction of our readers, not for gratuitous replies to questions of a purely business or personal nature. We will publish such inquiries, however, when paid for as advertisemets at $1.00 a line, under the head of "Business and Personal."

All reference to back numbers should be by volume and page._

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C.H.G., of N.Y.--To make pure nitrate of silver, dissolve pure silver in pure nitric acid, evaporate the solution to dryness, or, if crystals are preferred, evaporate until the solution is sufficiently concentrated to form crystals. If you can not get pure silver, you may purify it by dissolving coin in nitric acid, filtering the solution and precipitating the silver in the form of a chloride by hydrochloric acid. Next wash the precipitate with hot water until the washings cease to redden litmus paper. Next mix the pure chloride of silver while yet moist with its own weight of pure crystallized carbonate of soda, place the mixture in a covered porcelain crucible and heat very gradually until the fusing point of silver is reached. The reduced silver will be pure and may be removed by breaking the crucible. Wash the button thoroughly with hot water to remove the flux. In dissolving the pure silver thus obtained in nitric acid, it is better to use an excess of acid; the excess will be driven off by heat in evaporation.

G.B., of Iowa.--Nominal horse power is merely a conventional expression for diameter of cylinder and length of stroke, and does not apply to the actual power of the engine. It is found by multiplying the cube root of the stroke in feet by the square of the diameter in inches and dividing the product by 47. This rule is based upon the postulate established by Watt, that the speed of a piston with two feet stroke is 160 feet per minute, and that for longer strokes the speed varies as the cube roots of the length of the stroke. It is needless to say this rule is not observed in modern practice, yet the expression, nominal horse power, is like many other relics of past time still retained. The above rule does not apply to high pressure engines. For such engines Bourne has given the following rule: Multiply the square of the diameter of the cylinder in inches by the cube root of the stroke in feet, and divide by 15.6. The real power of an engine is estimated from the mean effective pressure in the cylinder--not the boiler--and the speed of the piston. Your data are insufficient to determine the horse power of your boiler. The horse power of boilers is estimated from the extent of heating surface when the grate and all other things are correctly proportioned, but with them as with engines, only actual test will positively determine it. The pipe you mention ought to be enlarged as proposed.

W.H.R., of Mass.--Pressure acts independently of the mode of application. A tun laid upon the head of a wedge would produce the same effect as though it were applied through toggles. When, however, a weight is dropped its effect increases as the square of its velocity.

J.B., of N.Y.--We recommend you to get "Appleton's Dictionary of Mechanics." Also send for descriptive catalogue to Henry Carey Baird, Philadelphia, from which you will be able to judge for yourself what works are suited to your requirements.

T.D.H., of Mass.--Ammonia, in a weak solution, may be used to cleanse the scalp, but is not recommended for the purpose. Borax in solution is better. The supposed preservation of the color of the hair by its use is a mistake.

F.B.H., of Ill.--So far as we know, nothing better than the flax seed bag has been discovered for packing the lower end of tubes in artesian wells. We have never heard of any trouble arising from the method and think you will have none.

L.G. of Mass.--Express the decimal ratio of the diameter of a circle to the circumference to which you refer, as a mixed vulgar fraction, and you will have what you ask for, if we understand your query.

A.H.S., of Sandwich Islands.--We know of no substance that in our opinion, could be used advantageously to paint the interior of sheet-iron evaporating pans for concentrating cane juice.

L.B., of Wis.--We would be glad to assist you but the data you furnish are not sufficient. The accurate solution of such a problem involves the higher mathematics.

A.H.M.--All animal and mineral oils are destructive to rubber. Linseed oil will not dissolve it. Oils should not be allowed to get on rubber belting.

T.W.J., of Pa.--For your rollers try some emery mixed in a solution of gum shellac in good alcohol.

E.B., of Mass.--The patent can be corrected by reissue.

J.M.T., of Ind.--To find the proper area for a safety valve port, when the evaporating surface is properly proportioned to the engine power, multiply the square of the diameter of the piston in inches by the speed in feet of the piston per minute, and divide the product by 375 times the pressure on the boiler per square inch. Having decided upon the length of the lever, the distance of the valve stem from the fulcrum, and the point from which the weight will be suspended, the weight necessary will be found by multiplying the area of the valve port in inches into the pressure per square inch in the boiler in pounds, and this product into the distance of the center of the valve stem from the fulcrum in inches, and dividing the product thus obtained by the distance from the fulcrum to the point of suspension of the weight in inches. The quotient will give the weight in pounds.

A.K.S., of Ohio.--The inclination of the poles of a planet to the plane of its orbit, determines its zones and also its seasons. The inclination of the earth's axis is twenty-three and one half degrees. This places the tropics the same distance each side of the equator, and the polar circles the same distance from the poles. The torrid zone is therefore forty-seven degrees wide, and the temperate zones each forty-three degrees wide. As the planets vary in their inclination of their axis to the planes of their orbits, it follows that their zones and seasons differ from those of the earth.

W.H.C., of Texas.--The teeth of a circular wood saw to be driven by foot-power, should be not larger than those of the ordinary hand crosscut. The fly-wheel ought to have a rim weighing from eighty to one hundred pounds, and it should be, for a 12-inch saw, not less than a foot in diameter. It should be placed on the saw arbor. The belt should not run on the fly-wheel, but on a special pulley, and the treadle and crank motion should be so adjusted that the foot will move through an arc of from 10 to 12 inches.

A.H.B., of Pa.--We advise you to use a battery in coating the small gray castings, of which you write, with copper. It will be all the more satisfactory in the end. The best polishing material to put in with them in the tumbler we think would be leather cuttings and sweepings. They will not need returning to the tumbler after being coppered. We recommend you to get "Byrne's Practical Metalworkers Assistant," published by Henry Carey Baird, Philadelphia.

J.H.G., of Tenn.--Don't put oil in your boiler to prevent incrustation. It will not probably do any good, and it will cause much foaming, while besides that it is a waste of heat, it is injurious to engines.

S.S.R., of Tenn.--No ammoniacal engines are, so far as we are aware, running in this country.

C.E.C., of Ohio.--The varnish for patterns is common shellac varnish. It is sometimes made black by lampblack.

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RECENT AMERICAN AND FOREIGN PATENTS.

_Under this heading we shall publish weekly notes of some of the more prominent home and foreign patents_.

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MOP.--Philip Cook, Jr., Sioux City, Iowa.--This invention relates to a new and useful improvement in mops, whereby they are so arranged that they may be wrung or freed from water when in use by moving the slides connected with the handle and head of the mop.

VENTILATING HORSE COVER.--Charles P. Eager, Boston., Mass.--This invention relates to a new horse cover, which is so arranged that it will be entirely waterproof, and nevertheless permit a free escape of air from the body of the animal.

CAR COUPLING.--S.O. Campbell, Tipton, Mo.--This invention relates to a new car coupling, which is so arranged that it will be self-coupling and retain the coupling pin ready to lock as long as the link is not inserted.

GAS STOVE.--Wm. J. Hays, New York city.--This invention has for its object to construct a gas stove, with an extender radiating surface, and with proper air channels, so that with a comparatively small amount of heat, the air in an ordinary-sized room can be properly warmed.

SCRIBE HOOK FOR WEATHER BOARDING.--John Nester, Portland, Oregon.--This invention relates to a new scribe hook for weather-boards, which will be generally useful and adaptable to the purposes for which it is intended and to provide an adjustable spur and marker.

RAILROAD SMOKE CONVEYER.--Lemuel Powell, Milford, Conn.--The object of this invention is to prevent the smoke and ashes, issuing from the smoke stack of a locomotive, from entering the cars of the train and from thereby preventing the proper ventilation of the cars.

DRILL FOR BORING POLYGONAL HOLES.--J.C. Broadley, Franklin, N.J.--This invention relates to a new implement for boring polygonal, oval, star-shaped, or holes of other suitable form, in metal, wood, or other material. The invention consists chiefly in arranging the pattern, which regulates the shape of the hole to be bored, on the upper part of the drill shank, and in having the bit shanks, which are pivoted to the lower part of the drill shank, held by means of springs against the inner edges of the inverted cup-shaped pattern.

ROOFING.--H.G. Noble, Selma, Ala.--This invention relates to improvements in roofing, and consists in covering roofs with sheet metal, laid on the rafters and nailed down at the edges, so as to be considerably concaved between them, the joints on the rafters being covered by inverted caps or troughs. The concave form of the sheet is designed to prevent the sheet metal from cracking, to which it is subject by expansion and contraction when laid on flat.

WASHING MACHINE.--John J. Kimball Naperville, Ill.--This invention relates to improvements in washing machines, and consists in an improved arrangement of operating mechanism for revolving a vertically suspended shaft with a crank at the top, and carrying within the tub a corrugated or roughened rubber, for action on the clothes. The invention also comprises an improved arrangement of the rubber, whereby it is made capable of sliding up or down on the shaft, according to the amount of clothes to be acted on.

BOLT CUTTER.--O.E. Butler and S.P. Dunham Marshalltown, Iowa.--This invention relates to improvements in hand instruments for cutting bolts, and consists in the combination with the handles of an instrument, such as patented to the inventors, January 19, 1869, as an improved instrument for sharpening horseshoes, of a cutting pin of peculiar construction, whereby the said tool is adapted, when this cutter is applied in substitution of the cutter and jaw, is used for sharpening horseshoes, to cut off the ends of bolts with great facility.

SHAFT TUG LUGS FOR HARNESS.--T.J. Magruder, Marion, Ohio.--This invention relates to improvements in the construction and application of shaft tug lugs for harness, and consists in forming the said lugs with broad and long plates, properly curved to suit the curve of the pad, and connecting the latter to the under sides of the skirts and to the pads in a way to stiffen the skirt and to hold the stud securely from breaking loose, the said lugs being made solid with a screw nut at the end to confine the bearing straps, or hollow, with female screw threads near the base, and bolts screwing into the said female threads to secure the bearing straps and to admit of readily applying or removing the straps so that the harness may be adapted for use either as single or double harness.

HARNESS BUCKLE.--J.W. Burch, Fayette, Miss.--The object of this invention is to provide buckles for harness and other uses, with tongues constructed in the form of leather punches, whereby they may be used at any time required for punching holes.

HUMMING-WHEEL TOY.--A.F. Able, New Orleans, La.--This invention relates to improvements in humming wheel toys, having for its object to provide an improved holding apparatus for supporting and maintaining the proper tension on the cords, and designed to support the cords of two or more wheels at the same time.

COMBINED CLOTHES IRONING TABLE AND CLOTHES DRYER.--William P. Adams, Brooklyn, N.Y.--This invention relates to a new and useful improvement in an article for the laundry, and consists in an adjustable ironing table, and in combination therewith a clothes dryer.

SEED AND GRAIN STRIPPER.--J.F. King and H.A. Rice, Louisiana, Mo.--The object of this invention is to provide a seed and grain stripper, with light and strong fingers, capable of adjustment as to hight, and arranged in a way to vary the spaces between the teeth at the point of stripping the heads for straw of different sizes.

CLOTHES WRINGER.--M.M. Follett, Lake City, Minn.--This invention relates to a new apparatus for applying pressure to the rollers of a wringer with an object of obtaining equal and adjustable power without any danger to the rubber of the rollers or to the articles to be dried.

AUGER HANDLE.--James Swan, Seymour, Conn.--The object of this invention is to provide a cheap, simple, and durable handle for augurs for boring in wood, one which shall require no fitting except to make the augur enter the socket, and which shall be of such size and shape that the shanks of ordinary augurs shall enter without any fitting at all.

CANDLESTICK.--H. Zahn, San Francisco, Cal.--This invention relates to a new and useful improvement in candlesticks, and consists in the use of a thumb screw in combination with the candlestick tube, whereby the candle is kept steady, and in a perpendicular position in the stick, and firmly held without the use of springs or other attachment.

WASHING MACHINE.--J.S. Merchant, Hopedale, Ohio.--This invention relates to new and useful improvements in machines for washing clothes.

PACKING CASES FOR OIL CANS.--John McLeod Murphy, New York city.--This invention consists of an arrangement especially adapted for use with cans provided with an improved cut off nozzle, which is the subject of an application for a patent, made by the same inventor and bearing even date herewith, which said improvement comprises the application to the ordinary vertical nozzles of a lateral spout connected to the side, and arranged to open an escape passage for the contents when the said spout is turned with the right position, which position is that best adapted for pouring from the can into another vessel, and in which the said spout projects through a slot in the side of the packing case in closing it, the said case being provided with an opening and a door for closing the same adapted for it.

WASHING MACHINE.--Edward Heim, Pittsburgh, Pa.--This invention relates to a new machine for washing clothes, and consists in the introduction of several improvements whereby the machine is adapted to thoroughly clean coarse as well as fine articles without injury to the same, and in a comparatively short time.

PADLOCK--John S. Rankin, Ann Arbor, Mich.--The object of this invention is to provide a simple, cheap, and efficient construction and arrangement of the locking and operating parts of padlocks. The invention consists in an improved and simple compound tumbler bolt and relative arrangement thereof with the bow and bow spring.

GRAIN DRILL.--Jacob F. Gibson, Chestnut Level, Pa.--This invention relates to a seed tube pivoted in its drag bars, in such manner that it may yield to an immovable obstruction.

PROPELLING MACHINERY OF COTTON GINS.--Wm. L. May, Linwood, Ala.--This invention has for its object to effect such arrangement of machinery as will enable a cotton gin to be run at a materially reduced expense.