For this the Spanish government, in 1514, gave secret orders to D'Avilla, Governor of Castila del Oro, and to Juan de Solis, the navigator, to determine whether Castila del Oro were an island, and to send to Cuba a chart of the coast, if any strait were possible. For this, De Solis visited Nicaragua and Honduras; and later, led far to the south, perished in the La Plata. For this, Magellan entered the straits, which, strangely enough, he affirmed before setting out, that he "would enter," since he "had seen them marked out on the geographer Martin Behaim's globe." For this, Cortez sent out his expeditions on both coasts, exposing his own life and treasure, and sending home to the emperor, in his second relation, a map of the entire Gulf of Mexico (Dispatch from Cortez to Charles V., October 15, 1524). For this great purpose, and in full expectancy of success in it, the whole coast of the New World on each side, from Newfoundland on the northeast, curving westward on the south, around the whole sweep of the Gulf of Mexico, thence to Magellan's Straits, and thence through them up the Pacific to the Straits of Behring, was searched and researched with diligence. "Men could not get accustomed," says Humboldt, "to the idea that the continent extended uninterruptedly both so far north and south." Hence all these large, numerous, and persevering expeditions by the European powers.

Among them, by priority of right and by her energy, was Spain. The great emperor was urgent on the conqueror of Mexico, and on all in subordinate positions in New Spain, to solve the secret of the strait. All Spain was awakened to it. "How majestic and fair was she," says Chevalier, "in the sixteenth century; what daring, what heroism and perseverance! Never had the world seen such energy, activity, or good fortune. Hers was a will that regarded no obstacles. Neither rivers, deserts, nor mountains far higher than those in Europe, arrested her people. They built grand cities, they drew their fleets, as in a twinkling of the eye, from the very forests. A handful of men conquered empires. They seemed a race of giants or demi-gods. One would have supposed that all the work necessary to bind together climates and oceans would have been done at the word of the Spaniards as by enchantment, and since nature had not left a passage through the center of America, no matter, so much the better for the glory of the human race; they would make it up by artificial communication. What, indeed, was that for men like them? It were done at a word. Nothing else was left for them to conquer, and the world was becoming too small for them."

Certainly, had Spain remained what she then was, what had been in vain sought from nature would have been supplied by man. A canal or several canals would have been built to take the place of the long-desired strait. Her men of science urged it. In 1551, Gomara, the author of the "History of the Indies," proposed the union of the oceans by three of the very same lines toward which, to this hour, the eye turns with hope.

"It is true," said Gomara, "that mountains obstruct these passes, but if there are mountains there are also hands; let but the resolve be made, there will be no want of means; the Indies, to which the passage will be made, will supply them. To a king of Spain, with the wealth of the Indies at his command, when the object to be obtained is the spice trade, what is possible is easy.

But the sacred fire suddenly burned itself out in Spain. The peninsula had for its ruler a prince who sought his glory in smothering free thought among his own people, and in wasting his immense resources in vain efforts to repress it also outside of his own dominions through all Europe. From that hour, Spain became benumbed and estranged from all the advances of science and art, by means of which other nations, and especially England, developed their true greatness.

Even after France had shown, by her canal of the south, that boats could ascend and pass the mountain crests, it does not appear that the Spanish government seriously wished to avail itself of a like means of establishing any communication between her sea of the Antilles and the South Sea. The mystery enveloping the deliberations of the council of the Indies has not always remained so profound that we could not know what was going on in that body. The Spanish government afterward opened up to Humboldt free access to its archives, and in these he found several memoirs on the possibility of a union between the two oceans; but he says that in no one of them did he find the main point, the height of the elevations on the isthmus, sufficiently cleared up, and he could not fail to remark that the memoirs were exclusively French or English. Spain herself gave it no thought. Since the glorious age of Balbao among the people, indeed, the project of a canal was in every one's thoughts. In the very wayside talks, in the inns of Spain, when a traveler from the New World chanced to pass, after making him tell of the wonders of Lima and Mexico, of the death of the Inca, Atahualpa, and the bloody defeat of the Aztecs, and after asking his opinion of El Dorado, the question was always about the two oceans, and what great things would happen if they could succeed in joining them.

During the whole of the seventeenth and eighteenth centuries, Spain had need of the best mode of conveyance for her treasures across the isthmus. Yet those from Peru came by the miserable route from Panama to the deadliest of climates. Porto Bello and her European wares for her colonies toiled up the Chagres river, while the roughest of communication farther north connected the Chimalapa and the Guasacoalcos in Mexico, and the trade there was limited sternly to but one port on each side. As late as Humboldt's visit, in 1802, when remarking upon the "unnatural modes of communication" by which, through painful delays, the immense treasures of the New World passed from Acapulco, Guayaquil, and Lima, to Spain, he says: "These will soon cease whenever an active government, willing to protect commerce, shall construct a good road from Panama to Porto Bello. The aristocratic nonchalance of Spain, and her fear to open to strangers the way to the countries explored for her own profit, only kept those countries closed." The court forbade, on pain of death, the use of plans at different times proposed. They wronged their own colonies by representing the coasts as dangerous and the rivers impassable. On the presentation of a memoir for improving the route through Tehuantepec, by citizens of Oaxaca, as late as 1775, an order was issued forbidding the subject to be mentioned. The memorialists were censured as intermeddlers, and the viceroy fell under the sovereign's displeasure for having seemed to favor the plans.

The great isthmus was, however, further explored by the Spanish government for its own purposes; the recesses were traversed, and the lines of communication which we know to-day were then noted.

In addition to the fact that comparatively little was explored north or south of that which early became the main highway, the Panama route, there is confirmation here of the truth that Spain concealed and even falsified much of her generally accurately made surveys. No stronger proof of this need be asked than that which Alcedo gives in connection with the proposal by Gogueneche, the Biscayan pilot, to open communication by the Atrato and the Napipi. "The Atrato," says the historian, "is navigable for many leagues, but the navigation of it is prohibited under pain of death, without the exception of any person whatever."

The Isthmus of Nicaragua has always invited serious consideration for a ship canal route by its very marked physical characteristics, among which is chiefly its great depression between two nearly parallel ranges of hills, which depression is the basin of its large lake, a natural and all-sufficient feeder for such a canal.

In 1524 a squadron of discovery sent out by Cortez on the coast of the South Sea, announced the existence of a fresh water sea at only three leagues from the coast; a sea which, they said, rose and fell alternately, communicating, it was believed, with the Sea of the North. Various reconnoissances were therefore made, under the idea that here the easy transit would be established between Spain and the spice lands beyond.

It was even laid down on some of the old maps, that this open communication by water existed from sea to sea; while later maps represented a river, under the name of Rio Partido, as giving one of its branches to the Pacific Ocean and the other to Lake Nicaragua. An exploration by the engineer, Bautista Antonelli, under the orders of Philip II., corrected the false idea of an open strait.

In the eighteenth century a new cause arose for jealousy of her neighbors and for keeping her northern part of the isthmus from their view. In the years 1779 and 1780 the serious purposes of the English government for the occupancy of Nicaragua, awakened the solicitudes of the Spanish government for this section. The English colonels, Hodgson and Lee, had secretly surveyed the lake and portions of the country, forwarding their plans to London, as the basis of an armed incursion, to renew such as had already been made by the superintendent of the Mosquito coast, forty years before, when, crossing the isthmus, he took possession of Realejo, on the Pacific, seeking to change its name to Port Edward. In 1780, Captain, afterward Lord Nelson, under orders from Admiral Sir Peter Parker, convoyed a force of two thousand men to San Juan de Nicaragua, for the conquest of the country.

In his dispatches, Nelson said: "In order to give facility to the great object of government, I intend to possess the lake of Nicaragua, which, for the present, may be looked upon as the inland Gibraltar of Spanish America. As it commands the only water pass between the oceans, its situation must ever render it a principal post to insure passage to the Southern Ocean, and by our possession of it Spanish America is severed into two."

The passage of San Juan was found to be exceedingly difficult; for the seamen, although assisted by the Indians from Bluetown, scarcely forced their boats up the shoals. Nelson bitterly regretted that the expedition had not arrived in January, in place of the close of the dry season. It was a disastrous failure, costing the English the lives of one thousand five hundred men, and nearly losing to them their Nelson.

At this period, Charles III., of Spain, sent a commission to explore the country. These commissioners reported unfavorably as regarded the route; but fearing further intrusion from England, forbade all access to the coast; even falsifying and suppressing its charts and permanently injuring the navigation of the San Juan and the Colorado by obstructions in their beds.

It is, however, a relief here to learn that when Humboldt visited the New World, he could say: "The time is passed when Spain, through a jealous policy, refused to other nations a thoroughfare across the possessions of which they kept the whole world so long in ignorance. Accurate maps of the coasts, and even minute plans of military positions, are published." It is also true that the Spanish Cortes, in 1814, decreed the opening of a canal, a decree deferred and never executed.

It was reserved for our century to see this great project carried into execution, and it is but just that as a chronicler of events I should connect with the Canal of Panama the name of a family who have done much to bring the scheme, so to say, into practical execution.

As early as the year 1836, Mr. Joly de Sabla turned his views toward the cutting of a canal across the Isthmus of Panama. He resided at the time on the Island of Guadeloupe, one of the French West India Islands, where he possessed large estates. Of a high social position, the representative of one of France's ancient and noble families, with large means at his disposal and of an enterprising spirit much in advance of his time, he was well calculated to carry out such a grand scheme.

He soon set about procuring from the Government of New Granada (now Colombia) the necessary grants and concessions, but much time and many efforts were spent before these could be brought to a satisfactory condition, and it was not until the year 1841 that he could again visit the Isthmus, bringing with him this time, on a vessel chartered by him for the purpose, a corps of engineers and employes, medical staff, etc., etc. After two years spent in exploring and surveying a country at that time very imperfectly known, he returned to Guadeloupe to find his residence and most of his estates destroyed by the terrible earthquake that visited the island in February, 1843.

Undaunted by this unexpected and severe blow, Mr. De Sabla persisted in his efforts, and in the same year obtained from the French government the establishment of a Consulate at Panama to insure protection to the future canal company, and also the sending of two government engineers of high repute (Messrs. Garella and Courtines), to verify the surveys already made and complete them.

After receiving the respective reports of Garella and Courtines, Mr. De Sabla decided upon first constructing a railway across the Isthmus, postponing the cutting of the canal until this indispensable auxiliary should have rendered it practicable and profitable. He then presented the scheme in that shape to his friends in Paris and London, and formed a syndicate of thirteen members, among whom we may recall the names of the well known Bankers Caillard of Paris, and Baimbridge of London, of Sir John Campbell, then Vice President of the Oriental Steamship Company, of Viscount Chabrol de Chameane, and of Courtines, the exploring engineer.

A new contract was then entered upon with New Granada in June, 1847, and early in 1848, the Syndicate was about to forward to the Isthmus the expedition which was to execute the preliminary works, while the company was being finally organized in Paris, and its stock placed.

The success of the undertaking seemed to be assured beyond peradventure, when the unexpected breaking out of the French revolution in February, 1848, dashed all hopes to the ground. Several of the prominent financiers engaged in the affair, taken by surprise by the suddenness of the revolution, had to suspend their payments and of course to withdraw from the Panama Canal and railroad scheme. Others withdrew from contagious fear and timidity. Finally the term fixed for carrying out certain obligations of the contract expired without their fulfillment by the company, and the concession was forfeited. Another contract was almost immediately applied for and granted with unseemly haste by the President of New Granada to Messrs. Aspinwall, Stephens and Chauncey, which resulted in the construction of the actual Panama Railroad.

These gentlemen acted fairly in the matter, and in 1849, calling Mr. De Sabla to New York, offered him to join them in the new scheme. Unfortunately they had decided upon placing the Atlantic terminus of the railroad upon the low and swampy mud Island of Manzanillo, while Mr. De Sabla insisted on having it on the mainland on the dry and healthy northern shore of the Bay of Limon. They could not come to an understanding on this point, and Mr. De Sabla, whose experience and foresight taught him the dangers that would result to the shipping from the unprotected situation of the projected part (now Colon—Aspinwall), and who well knew the insalubrity of the malarial swamp constituting the Island of Manzanillo, withdrew forever from the undertaking, after having devoted to it without any benefit to himself, the best years of his life and a large portion of his private means.

One of his sons, Mr. Theodore J. de Sabla, after having actively co-operated with Lieutenant Commander Wyse, in the original scheme of the present canal company, is now one of Count de Lesseps's representatives in the City of New York, and a director of the Panama Railroad Company.

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IMPROVED AVERAGING MACHINE.

At the recent meeting of the American Society of Civil Engineers, in this city, a paper on an improved form of the averaging machine was read by its inventor, Mr. Wm. S. Auchincloss.

The ingenious method by which the weight of the platform is eliminated from the result of the work of the machine was exhibited and explained. This is accomplished by counterweights sliding automatically in tubes, so that in any position the unloaded platform is always in equilibrium. Any combination of representative weights can then be placed on this platform at the proper points of the scale. By then drawing the platform to its balancing point, the location of the center of gravity will at once be indicated on the scale by the pointer over the central trunnion.

The weights may be arranged on a decimal system, with intermediate weights for closer working, or they may be made so as to express multiples or factors.

Each machine is provided with a number of differing scales, divided suitably for various purposes. When the problem is one of time, the scale represents months and days; for problems of proportion, the zero of the scale is at the center of its length; for problems for the location of center of gravity of a system from a fixed point, the zero is at the extremity of the scale, etc.

The machine exhibited has sixty-three transverse grooves, which, by arrangement of weights, can be made to serve the purposes of two hundred and fifty-two grooves.

The machine is 29 inches in length, 9 inches in width, and weighs about 13 pounds.

With the machine can be found average dates, as, for instance, of purchases and of payments extending over irregular periods; also average prices, as for "futures," in comman use among cotton brokers. The problem of average haul, so often presented to the engineer, can be solved with ease and great celerity. Practical examples of the solution of these and a number of other problems involving proportions or averages were given by the author.

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COMPOUND BEAM ENGINE.

The engine represented in Figs. 1 to 4 herewith is intended for a mill, and is of 530 to 800 indicated horse-power, the pressure being seven atmospheres, and the number of revolutions forty-five per minute. As will be seen by the drawing each cylinder is placed in a separate foundation plate, the two connecting rods acting upon cranks keyed at right angles upon the shaft, W, which carries the drum, T. The high-pressure cylinder, C, is 760 mm diameter, the low pressure cylinder being 1,220 mm. diameter, and the piston speed 2.28 m. The drum, which also fulfills the purpose of a fly wheel, is provided with twenty-eight grooves for ropes of 50 mm. diameter. With the exception of the cylinders, pistons, valves, and valve chests, the engines are of the same size, corresponding to the equal maximum pressures which come into action in each cylinder, and in this respect alone the engine differs in principle from an ordinary twin machine.



The steam passes from the stop-valve, A, Fig. 4, through the steam pipe, D, to the high pressure cylinder, C, and having done its work, goes into the receiver, R, where it is heated. From the receiver it is led into the low-pressure cylinder, C1, and thence into the condenser. Provision is made for working both engines independently with direct steam when desired, suitable gear being provided for supplying steam of the proper pressure to the condensing engine, so that each engine shall perform exactly the same amount of work. The starting gear consists of a hand-wheel, H, which controls the stop valve, A, and of another h, which opens the valves for the jackets of the cylinders and receiver. The hand-wheel, h1 and h2, govern the valves, which turn the steam direct into the two cylinders. There are also lever, g, which opens the principal injection cock, H1, and the auxiliary injection cock, H2, the function of which is to assist in forming a speedy vacuum, when the engine has been standing for some time.



The drum is 6.08 m. diameter, the breadth being 2.04 m., with a total weight of 33,000 kilos. The beams are of cast iron with balance weights cast on. The connecting rods and cross beams are of wrought iron, and the cranks, crank shaft, piston rods, valve rods, etc., of steel. The bed-plate for the main shaft bearings are cast in one piece with the standards for the beam, which are connected firmly together by the center bearing, M M1, which is cast in one piece, and also by the diagonal bracing piece, N N1. The construction of the cylinder and valve chests is shown in Fig. 1. The working cylinder is in the form of a liner to the cylinder, thus forming the steam jacket, with a view to future renewal. This lining has a flange at the lower part for bolting it down, being made steam-tight by the intervention of a copper packing ring. There is a similar ring at the upper part which is pressed down by the cylinder cover. The latter is cast hollow and strengthened by ribs. The pistons are provided with cast iron double self-expanding packing rings. For preventing accidents by condensed water, spring safety valves, ss and s1 s1, are connected to the valve chests. The valve gear, which is arranged in the same manner for both cylinders, is actuated by shafts, w and w1, rotated by toothed wheels as shown. Motion is communicated from the way-shafts, w and w1, by the eccentrics, and the eccentric rods, e1 e2 e3 e4, and the levers and rods belonging thereto, to the short steam valve rocking shafts levers, f1 f2 f3 f4, and the exhaust valve rocking shafts, k1 k2 k3 k4, the bearings of which are carried on brackets above the valve chests, which, being furnished with tappet levers, raise and lower the valves.



The valves are conical, double-seated, and of cast iron, and the inlet and outlet valves are placed the one above the other, the seats being also conically ground and inserted through the cover of the valve chest. Both inlet and outlet valves are actuated from above, and are removable upward, an arrangement which admits of the valves being more easily examined than when the two are actuated from different sides of the valve chest. To carry out this idea the inlet valves are furnished with two guides, which, passing upward through the stuffing-box, are attached to a hard steel cross piece, which receives the action of a bent catch turning on a pin attached to the levers, t1, t2, t3, t4. The exhaust valves, on the contrary, have only one guide each, which passes upward through the seat of the admission valve, through the valve itself by means of a collar, and through the stuffing-box. It is furnished with hard steel armatures, through which the levers, z1 z2, Fig. 3, act upon the exhaust valves.



The governor effects the acceleration or retardation of the loosening of the catch actuating the steam valve by means of hard steel projections on the shaft, v1, the position of which, by means of levers, is regulated by the governor, which in its highest position does not allow the lifting of the inlet valve at all. The regulation of the expansion by the governor from 0 to 0.45 takes place generally only in the case of the high-pressure cylinder, while the low-pressure cylinder has a fixed rate of expansion. Only when the low-pressure cylinder is required to work with steam direct from the boiler is the governor applied to regulate the expansion in it. An exact action in the valve guides and a regular descent is secured by furnishing them with small dash pot pistons working in cylinders. Into them the air is readily admitted by a small India-rubber valve, but the passage out again is controlled at pleasure.—The Engineer.

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TO DETECT ALKALIES IN NITRATE OF SILVER—Stolba recommends the salt to be dissolved in the smallest quantity of water, and to add to the filtered solution hydrofluosilicic acid, drop by drop. Should a turbidity appear an alkaline salt is present. But should the liquid remain limpid, an equal volume of alcohol is to be added, which will cause a precipitate in case the slightest trace of an alkali be present.

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POWER HAMMERS WITH MOVABLE FULCRUM.

[Footnote: Paper read before the Institution of Mechanical Engineers.—Engineering.]

By DANIEL LONGWORTH, of London.

The movable-fulcrum power hammer was designed by the writer about five and a half years ago, to meet a want in the market for a power hammer which, while under the complete control of only one workman, could produce blows of varying forces without alteration in the rapidity with which they were given. It was also necessary that the vibration and shock of the hammer head should not be transmitted to the driving mechanism, and that the latter should be free from noise and liability to derangement. The various uses to which the movable fulcrum hammers have been put, and their success in working[1]—as well as the importance of the general subject which includes them, namely, the substitution of stored power for human effort—form the author's excuse for now occupying the time of the meeting.

[Footnote 1: The hammers have been for some years used by A. Bamlett, of Thirsk; the American Tool Company, of Antwerp; Messrs. W.&T. Avery, of Birmingham; Pullar & Sons, of Perth; Salter & Co., of West Bromwich; Vernon Hope & Co., of Wednesbury, etc.; and also for stamps by Messrs. Collins & Co., of Birmingham, etc.]

Until these hammers were introduced, no satisfactory method had been devised for altering the force of the blow. The plan generally adopted was to have either a tightening pulley acting on the driving belt, a friction driving clutch, or a simple brake on the driving pulley, put in action by the hand or foot of the workman. Heavy blows were produced by simply increasing the number of blows per minute (and therefore the velocity), and light blows by diminishing it—a plan which was quite contrary to the true requirements of the case. To prevent the shock of the hammer head being communicated to the driving gear, an elastic connection was usually formed between them, consisting of a steel spring or a cushion of compressed air. With the steel spring, the variation which could be given in the thickness of the work under the hammer was very limited, owing to the risk of breaking the spring; but with the compressed air or pneumatic connection the work might vary considerably in thickness, say from 0 to 8 in. with a hammer weighing 400lb. The pneumatic hammers had a crank, with a connecting rod or a slotted crossbar on the piston-rod, a piston and a cylinder which formed the hammer-head. The piston-rod was packed with a cup leather, or with ordinary packing, the latter required to be adjusted with the greatest nicety, otherwise the piston struck the hammer before lifting it, or else the force of the blow was considerably diminished. As the piston moved with the same velocity during its upward and downward strokes, and, in the latter, had to overtake and outrun the hammer falling under the action of gravity, the air was not compressed sufficiently to give a sharp blow at ordinary working speeds, and a much heavier hammer was required than if the velocity of the piston had been accelerated to a greater degree.

As it is impossible in the limits of this paper to describe all the forms in which the movable fulcrum hammers have been arranged, two types only will be selected taken from actual work; namely, a small planishing hammer, and a medium-sized forging hammer.[1]

[Footnote 1: To the makers, Messrs. J. Scott Rawlings & Co, of Birmingham, the author is indebted for the working drawings of these hammers.]

The small planishing hammer, Figs. 1 to 3, next page, is used for copper, tin, electro, and iron plate, for scythes, and other thin work, for which it is sufficient to adjust the force of the blow once for all by hand, according to the thickness and quality of the material before commencing to hammer it. The hammer weighs 15 lb., and has a stroke variable from 2 in. to 9 in., and makes 250 blows per minute. The driving shaft, A, is fitted with fast and loose belt pulleys, the belt fork being connected to the pedal, P, which when pressed down by the foot of the workman, slides the driving belt on to the fast pulley and starts the hammer; when the foot is taken off the pedal, the weight on the latter moves the belt quickly on to the loose pulley, and the hammer is stopped. The flywheel on the shaft, A, is weighted on one side, so that it causes the hammer to stop at the top of its stroke after working; thus enabling the material to be placed on the anvil before starting the hammer. The movable fulcrum, B, consists of a stud, free to slide in a slot, C, in the framing, and held in position by a nut and toothed washer. On the fulcrum is mounted the socket, D, through which passes freely a round bar or rocking lever, E, attached at one end to the main piston, F, of the hammer, G, and having at the other extremity a long slide, H, mounted upon it. This slide is carried on the crank-pin, I, fastened to the disk, J, attached to the driving shaft, A. The crank-pin, in revolving, reciprocates the rocking lever, E, and main piston, F, and through the medium of the pneumatic connection, the hammer, G. The slide, H, in revolving with the crank-pin, also moves backward and forward along the rocking lever, approaching the fulcrum, B, during the down-stroke of the hammer, and receding from it during the up-stroke. By this means the velocity of the hammer is considerably accelerated in its downward stroke, causing a sharp blow to be given while it is gently raised during its upward stroke.

To alter the force of the blow, the hammer, G, is made to rise and fall through a greater or less distance, as may be required, from the fixed anvil block, K, after the manner of the smith giving heavy or light blows on his anvil. It is evident that this special alteration of the stroke could not be obtained by altering the throw of a simple crank and connecting rod; but by placing the slot, C, parallel with the direction of the rocking lever, E, when the latter is in its lowest position, with the hammer resting on the anvil, and with the crank at the top of its stroke, this lowest position of the rocking lever and hammer is made constant, no matter what position the fulcrum, B, may have in the slot, C. To obtain a short stroke, and consequently a light blow, the fulcrum is moved in the slot toward the hammer, G; and to produce a long stroke and heavy blow the fulcrum is moved in the opposite direction.

Fig. 3 gives the details of the pneumatic connection between the main piston and the hammer, in which packing and packing glands are dispensed with. The hammer, G, is of cast steel, bored out to fit the main piston, F, the latter being also bored out to receive an internal piston, L. A pin, M, passing freely through slots in the main piston, F, connects rigidly the internal piston, L, with the hammer, G. When the main piston is raised by the rocking lever, the air in the space, X, between the main and internal pistons, is compressed, and forms an elastic medium for lifting the hammer; when the main piston is moved down, the air in the space, Y, is compressed in its turn, and the hammer forced down to give the blow. Two holes drilled in the side of the hammer renew the air automatically in the spaces, X and Y, at each blow of the hammer.

Figs. 4 to 6, on the next page, represent the medium size forging hammer, for making forgings in dies, swaging and tilting bars, and plating edged tools, etc.

The hammer weighs 1 cwt., has a stroke variable from 4 in. to 14 in., and gives 200 blows per minute; the compressed air space between the main piston and the hammer is sufficiently long to admit forgings up to 3 in. thick under the hammer.

To make forgings economically, it is necessary to bring them into the desired form by a few heavy blows, while the material is still in a highly plastic condition, and then to finish them by a succession of lighter blows. The heavy blows should be given at a slower rate than the lighter ones, to allow time for turning the work in the dies or on the anvil, and so to avoid the risk of spoiling it. In forging with the steam hammer the workman requires an assistant, who, with the lever of the valve motion in hand, obeys his directions as to starting and stopping, heavy or light blows, slow or quick blows, etc; the quickest speed attainable depending on the speed of the arm of the assistant. In the movable-fulcrum forging hammer the operations of starting and stopping, and the giving of heavy or light blows, are under the complete control of one foot of the workman, who requires therefore no assistant; and by properly proportioning the diameter of the driving pulley and size of belt to the hammer, the heavy blows are given at a slower rate than the light ones, owing to the greater resistance which they offer to the driving belt.

In this hammer the pneumatic connection, the arrangements for the starting, stopping, and holding up of the hammer, as well as those for communicating the motion of the crank-pin to the hammer by means of a rocking lever and movable fulcrum, are similar to those in the planishing hammer, differing only in the details, which provide double guides and bearings for the principal working parts.



The movable fulcrum, B, Figs. 4 and 5, consists of two adjustable steel pins, attached to the fulcrum lever, Q, and turned conical where they fit in the socket, D. The fulcrum lever is pivoted on a pin, R, fixed in the framing of the machine, and is connected at its lower extremity to the nut, S, in gear with the regulating screw, T. The to-and-fro movement of the fulcrum lever, Q, by which heavy or light blows are given by the hammer, is placed under the control of the foot of the workman, in the following manner: U is a double-ended forked lever, pivoted in the center, and having one end embracing the starting pedal, P, and the other end the small belt which connects the fast pulley on the driving shaft, A, with the loose pulley, V, or the reversing pulleys, W and X. These are respectivly connected with the bevel wheels, W{1}, and X{1}, gearing into and placed at opposite sides of the bevel wheel, Z, on the regulating screw in connection with the fulcrum lever. When the workman places his foot on the pedal, P, to start the hammer, he finds his foot within the fork of the lever, U; and by slightly turning his foot round on his heel he can readily move the forked lever to right or left, so shifting the small belt on to either of the reversing pulleys, W or X, and causing the regulating screw, T, to revolve in either direction. The fulcrum lever is thus caused to move forward or backward, to give light or heavy blows. By moving the forked lever into mid position, the small belt is shifted into its usual place on the loose pulley, V, and the fulcrum remains at rest. To fix the lightest and heaviest blow required for each kind of work, adjustable stops are provided, and are mounted on a rod, Y, connected to an arm of the forked lever. When the nut of the regulating screw comes in contact with either of the stops, the forked lever is forced into mid position, in spite of the pressure of the foot of the workman, and thus further movement of the fulcrum lever, in the direction which it was taking, is prevented. The movable fulcrum can also be adjusted by hand to any required blow, when the hammer is stopped, by means of a handle in connection with the regulating screw.

In conclusion the author wishes to direct attention to the fact, that in many of our largest manufactories, particularly in the midland counties, foot and hand labor for forging and stamping is still employed to an enormous extent. Hundreds of "Olivers," with hammers up to 60 lb. in weight, are laboriously put in motion by the foot of the workman, at a speed averaging fifty blows per minute; while large numbers of stamps, worked by hand and foot, and weighing up to 120 lb., are also employed. The low first cost of the foot hammers and stamps, combined with the system of piece work, and the desire of manufacturers to keep their methods of working secret, have no doubt much to do with the small amount of progress that has been made; although in a few cases competition, particularly with the United States of America, has forced the manufacturer to throw the Oliver and hand-stamp aside, and to employ steam power hammers and stamps. The writer believes that in connection with forging and stamping processes there is still a wide and profitable field for the ingenuity and capital of engineers, who choose to occupy themselves with this minor, but not the less useful, branch of mechanics.

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THE BICHEROUX SYSTEM OF FURNACES APPLIED TO THE PUDDLING OF IRON.

Since the year 1872, the large iron works at Ougre, near Liege, have applied the Bicheroux system of furnaces to heating, and, since the year 1877, to puddling. The results that have been obtained in this last-named application are so satisfactory that it appears to us to be of interest to speak of the matter in some detail.

The apparatus, which is shown in the opposite page, consists of three distinct parts: (1) a gas generator; (2) a mixing chamber into which the gases and air are drawn by the natural draught, and wherein the combustion of the gases begins; and (3) a furnace, or laboratory (not represented in the figure), wherein the combustion is nearly finished, and wherein take place the different reactions of puddling. These three parts are given dimensions that vary according to the composition of the different coals, and they may be made to use any sort of coal, even the fine and schistose kinds which would not be suitable for ordinary puddling. The gases and the air necessary for the combustion of these being brought together at different temperatures, and being drawn into the mixing chamber through the same chimney, it will be seen that the dimensions of the flues that conduct them should vary with the kind of coal used; and the manner in which the gases are brought together is not a matter of indifference.



The gas generator consists of a hopper, A, into which drops, through small apertures a, the coal piled up on the platform, D. These apertures are closed with coal or bricks. The bottom of the generator is formed of a small standing grate. The coal, on falling upon a mass in a state of ignition, distills and becomes transformed into coke, which gradually slides down over a grate to produce afterward, through its own combustion, a distillation of the coal following it. But as these are features found in all generators we will not dwell upon them.

The gases that are produced flow through a long horizontal flue, B, into a vertical conduit, E, into which there debouches at the upper part a series of small orifices, F, that conduct the air that has been heated. The gases are inflamed, and traverse the furnace c (not shown in the cut), from whence they go to the chimney. Before the air is allowed to reach the intervening chamber it is made to pass into the sole of the furnace and into the walls of the chamber, so that to the advantage of having the air heated there is joined the additional one of having those portions of the furnace cooled that cannot be heated with impunity.

The incompletely burned gases that escape from the furnace are utilized in heating the boilers of the establishment. The dimensions given these furnaces vary greatly according to the charge to be used. All the results at Ougre have been obtained with 400 kilogramme charges, and the dimensions of the gas generators have been calculated for Six-Bonniers coal, which does not yield over 20 per cent. of gas.

The advantages of this system, which permits of expediting all the operations of puddling, are as follows:

1. A notable economy in fuel, both as regards quantity and quality.

2. Economy resulting from diminution in the waste of metal, with a consequent improvement in the quality of the products obtained.

3. Diminution in cost of repairs.

4. Less rapid wear in the grates.

5. Improvement in the conditions of the work of puddling.

As regards the first of these advantages, it may be stated that the puddling of ordinary Ougre forge iron, which required with other furnaces 900 to 1,000 kilogrammes of coal, is now performed with less than 600 kilogrammes per ton of the iron produced. The puddling of fine grained iron which required 1,300 to 1,500 kilogrammes of coal is now done with 800. So much for quantity; as for quality the system presents also a very marked advantage in that it requires no rolling coal—the operation of the furnace being just as regular with fine coal, even that sifted through screens of 0.02 meter.

The second class of advantages naturally results from the almost complete prevention of access of cold air. The saving in wastage amounts to 3 or 4 per cent., that is to say, 100 kilogrammes of iron produced is accompanied by a loss of only 9 to 10 kilogrammes, instead of 13 to 15 as ordinarily reckoned.

The diminution in the cost of repairs is due to the fact that the furnace doors, of which there are two, permit of easy access to all parts of the sole; moreover, the coal never coming in contact with the fire-bridges, the latter last much longer than those in other styles of furnaces, and can be used for several weeks without the necessity of the least repair. The reduced wear of the grates results from the low temperature that can be used in the furnace, and the quantity of clinker that can be left therein without interfering with its operation, thus permitting of having the grates always black. These latter in no wise change, and after five months of work the square bars still preserve their sharpness of edges.

As for the improvements in the conditions of the work of puddling, it may be stated that with a uniform price per 100 kilogrammes for all the furnaces, the laborers working at the gas furnaces can earn 25 to 30 per cent. more than those working at ordinary furnaces.

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GESSNER'S CONTINUOUS CLOTH-PRESSING MACHINE.

It is well known that there are several serious drawbacks in the usual plan of pressing woolen or worsted cloths and felts with press plates, press papers, and presses. Three objections of great weight may be mentioned, and events in Leeds give emphasis to a fourth. The three objections are—the labor required in setting or folding the cloth, the expense of the press papers, and the time required. The fourth objection, about which a dispute has occurred between the press-setters and the master finishers in Leeds, refers to the inapplicability of the common system to long lengths. The men object to these on account of the great labor involved in shifting the heavy mass of cloth and press plates to and from the presses. A minor drawback of this system is that it involves the presence of a fold up the middle of the piece. On account of these drawbacks it has long been understood to be desirable to expedite the process, and also to dispense with the press papers. This is the main purpose of the machine we now illustrate in section, in which the pressing is done continuously by what may be termed a species of ironing. The machine consists of a central hollow cylinder, C, three-quarters of the circumference of which is covered by the hollow boxes, M, heated by steam through the pipes shown, and which are mounted upon the levers, BB', whose fulcra are at bb. By means of the hand-wheel, T, and worm-wheel, n, which closes or opens the levers, BB', the pressure of the boxes upon the central roller may be adjusted at will, the spring-bolt, F, allowing a certain amount of yield. The faces of the press-boxes, MM, are covered by a curved sheet of German silver attached to the point, Y. This sheet takes the place of the press papers in the ordinary process. The course of the cloth through the machine is as follows, and is shown by the arrows: It is placed on the bottom board in front, and in its travel it passes over the rails, O, after which it is operated on by the brush, Z, leaving which it is conveyed over the rails, V and I, the rollers, K and P, and thence between the pressing roller, C, and the German silver press plate covering the heated boxes, M. Leaving these the piece passes over the roller, P, and is cuttled down in the bottom board by the cuttling motion, F, or a rolling-up motion may be applied. The maker states that arrangements for brushing and steaming may also be attached, so that in one passage through the machine a piece may be pressed, brushed, and steamed. The speed of the cylinder may be adjusted according to the quality or requirements of the goods that are under treatment. At the time of our visit, says the Textile Manufacturer, printed woolen pieces were being pressed at the rate of about four yards a minute, but higher speeds are often obtained. Messrs. Taylor, Wordsworth & Co., who have erected many of these machines in Leeds, Bradford, and Batley, inform us that they find they are adapted for the pressing of a wide variety of cloths, from Bradford goods and thin serges to the heavy pieces of Dewsbury and Batley. The inventor, Ernst Gessner, of Aue, Saxony, adopts an ingenious expedient for pressing goods with thick lists. He provides an arrangement for moving the cylinder endwise, according to the different widths of the pieces to be treated. One list is left outside at the end of the cylinder, and the other at the opposite end of the pressing boxes. The machine we saw was 80 in. wide on the roller, and it was one the design and construction of which undoubtedly do credit to Mr. Gessner.



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IMPROVEMENTS IN WOOLEN CARDING ENGINES.

Mr. Bolette, who has made a name for himself in connection with strap dividers, has experimented in another direction on the carding engine, and as his ideas contain some points of novelty we herewith give the necessary illustrations, so that our readers can judge for themselves as to the merit of these inventions.



Fig. 1 represents the feeding arrangement. Here the wool is delivered by the feed rollers, A A, in the usual manner. The longer fibers are then taken off by a comb, B, and brought forward to the stripper, E, which transfers them to the roller, H, and thence to the cylinder. The shorter fibers which are not seized by the comb fall down, but as they drop they meet a blast of air created by a fan, which throws the lighter and cleaner parts in a kind of spray upon the roller, L, whence they pass on to the cylinder, while the dirt and other heavier parts fall downwards into a box, and are by this means kept off the cylinder. It is evident that in this arrangement it is not intended to keep the long and the short fibers separate, but to utilize them all in the formation of the yarn. The arrangement shown in Fig. 2 refers to the delivery end. Instead of the sliver being wound upon the roller in the usual way, it runs upon a sheet of linen, P, as in the case of carding for felt, with a to-and-fro motion in the direction of the axis of the rollers. In this way one or more layers of the fleece can be placed on the sheet, which in that case passes backwards and forwards from roller S to R, and vice versa. It is, in fact, the bat arrangement used for felt, only with this difference, that the bat is at once rolled up instead of going through the bat frame. In the manufacture of felt it is of course of importance to have many very thin layers of fleece superposed over each other in order to equalize it, and if the same is applied to the manufacture of cloth it will no doubt give satisfactory results, but may be rather costly.



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NOVELTIES IN RING SPINDLES.

One of the drawbacks of ring spinning is the uneven pull of the traveler, which is the more difficult to counteract as it is exerted in jerks at irregular intervals. It is argued that with spindles and bearings as usually made the spindle is supported firmly in its bearing, and cannot give in case of such a lateral pull when exerted through the yarn by the traveler, and the consequence is either a breakage of the yarn or an uneven thread. Impressed with this idea, and in order to remedy this defect, an eminent Swiss firm has hit upon the notion of driving the spindle by friction, and to make it more or less loose in the bearings, so that in case of an extra pull by the traveler the spindle can give way a little, and thus prevent the breakage of the yarn. This idea has been carried out in four different ways, and as this seems to be an entirely new departure in ring spinning, we give the illustrations of their construction in detail.



Fig. 1 represents Bourcart's recent arrangement of attaching the thread guide to the spindle rail and the adjustable spindle. The spindle is held by the sleeve, g, which latter is screwed into the spindle rail, S, this being moved by the pinion, a; the collar is elongated upwards in a cuplike form, c, the better to hold the oil, and keep it from flying; d is the wharf, which has attached to it the sleeve, m, and which is situated loosely in the space between the spindle and the footstep, e. Above the wharf the spindle is hexagonal in shape, and to this part is attached the friction plate, a. Between the latter and the upper surface of the wharf a cloth or felt washer is inserted, to act as a brake. The footstep, e, is filled with oil, in which run the foot of the spindle and the sleeve m, the latter turning upon a steel ring situated on the bottom of the footstep. As, thus, the foot of the spindle is quite free, the upper part of the spindle can give sideways in the direction of any sudden pull, and the foot of the spindle can follow this motion in the opposite direction, the collar forming the fulcrum for the spindle. By this alteration of the vertical position of the spindle into an inclined one (though ever so trifling), the contact of the friction plate, a, and the wharf is interrupted, and thus the speed of the spindle reduced. This will cause less yarn to be wound on, and the pull thus to be neutralized; but as the wharf keeps turning at the same speed, its centrifugal force will act again upon the friction plate, and thus bring the spindle back to its vertical position as soon as the extra drag has been removed.

In Fig. 2 the footstep, e, has the foot of the spindle more closely fitting at the bottom, but the upper part of the step opens out gradually, and forms a conical cavity of a little larger diameter than the spindle, so that the latter has a considerable play sideways. The wharf carries in its lower part the sleeve, g, which runs upon a steel ring as above. The upper surface of the wharf is arched, and upon this is fitted the correspondingly arched friction plate, a, which latter is attached to the spindle by a screw. The position of the spindle is maintained by the collar, m. This collar is loose in the spindle rail, and only held by the spring, m'. If now, a lateral drag is exerted upon the upper part of the spindle, the collar car follows the direction of this drag, and the spindle thus be brought out of the vertical position, the friction plate slipping at the same time. The force of the spring conjointly with the centrifugal force will then bring back the spindle into its normal position as soon as the drag is again even.

Fig. 3 shows a spindle with a very long conical oil vessel, B, resting upon a disk, e", in cup, e', with a cover, e"'. The wharf, d, is here situated high up the spindle, has the same sleeve as in the preceding case, and runs round the bush, g, upon the ring, z. The friction plate resting upon the wharf is joined to the collar, a, running out into a cup shape, which is fixed to the spindle, which here has a hexagonal form. In this case the collar gives with the spindle, which latter has the necessary play in the long footstep; and as the collar and friction-plate are one, it is brought back to its normal place by centrifugal force.

A peculiar arrangement is shown in Fig. 4. Here the ring and traveler, f, are placed as usual, but the spindle carries at the same time an inverted flier, t. The spindle turns loosely in the footstep, e, the oil chamber being carried up to the middle of its height. The wharf is placed in the same position as in the previous case, having also a sleeve running in the oil chamber, c, upon a steel ring, z. The friction-plate a, on the top of the wharf carries the flier, and on its upper surface is in contact with the inverted cup, a, which is attached to the spindle by a pin or screw. In order to limit at will the lateral motion of the spindle there is attached to the latter, between the footstep and the collar, a split ring, i, which can be closed more or less by a small set screw. The spindle is thus only held in the perpendicular position by its own velocity, which will facilitate a high degree of speed, through the entire absence of all friction in the bearings, this vertical position being assisted by the friction motion whenever the spindle has been drawn on one side. Although the notion of mounting spindles so that they can yield in order to center themselves is not new, it is evident that considerable ingenuity has been brought to bear upon the arrangement of the spindles we have described, but we are not in a position to say to what extent practice has in this case coincided with theory.—Textile Manufacturer.

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PHOTO-ENGRAVING ON ZINC OR COPPER.

By LEON VIDAL.

This process is similar in many respects to the one which was some time ago communicated to the Photographic Society of France by M. Stronbinsky, of St. Petersburg, but in a much improved and complete form. An account of it was given by M. Gobert, at the meeting of the same society, on the 2d December, 1882. The following are the details, as demonstrated by me at the meeting of the 9th of May last:

Sheets of zinc or of copper of a convenient size are carefully planished and polished with powdered pumice stone. The sensitive mixture is composed of:

The whites of four fresh eggs beaten to a froth......................... 100 parts Pure bichromate of ammonia......... 2.50 " Water.............................. 50 "

After this mixture has been carefully filtered through a paper filter, a few drops of ammonia are added. It will keep good for some time if well corked and preserved from exposure to the light. Even two months after being prepared I have found it to be still good; but too large a quantity should not be prepared at a time, as it does not improve with keeping.

I find that the dry albumen of commerce will answer as well as the fresh. In that case I employ the following formula:

Dry albumen from eggs.............. 15 to 20 parts Water.............................. 100 " Ammonia bichromate................. 2.50 "

Always add some drops of ammonia, and keep this mixture in a well corked bottle and in a dark place.

To coat the metal plate, place it on a turning table, to which it is made fast at the center by a pneumatic holder; to assure the perfect adhesion of this holder, it is as well to wet the circular elastic ring of the holder before applying it to the metallic surface. When this is done, the table may be made to rotate quickly without fear of detaching the plate by the rapidity of the movement. The plate is placed in a perfectly horizontal position, where no dust can settle on it; the mixture is then poured on it, and distributed by means of a triangular piece of soft paper, so as to cover equally all the parts of the plate. Care should be taken not to flow too much liquid over the plate, and when the latter is everywhere coated, the excess is poured off into a different vessel from that which contains the filtered mixture, or else into a filter resting on that vessel. The turning table should now be inverted so that the sensitive surface may be downwards, and it is made to rotate at first slowly, afterwards more rapidly, so as to make the film, which should be very thin, quite smooth and even. The whole operation should be carried out in a subdued light, as too strong a light would render insoluble the film of bichromated albumen.

When the film is equalized the plate must be detached from the turning table and placed on a cast iron or tin plate heated to not more than 40 or 50 C. A gentle heat is quite sufficient to dry the albumen quickly; a greater heat would spoil it, as it would produce coagulation. So soon as the film is dry, which will be seen by the iridescent aspect it assumes, the plate is allowed to cool to the ordinary temperature, and is then at once exposed either beneath a positive, or beneath an original drawing the lines of which have been drawn in opaque ink, so as to completely prevent the luminous rays from passing through them; the light should only penetrate through the white or transparent ground of the drawing.

I say a positive because I wish to obtain an engraved plate; if I wanted to have a plate for typographic printing, I should have to take a negative. After exposure the plate must be at once developed, which is effected by dissolving in water those parts of the bichromated gelatine which have been protected from the action of light by the dark spaces of the clich; these parts remain soluble, while the others have been rendered completely insoluble. If the plate were dipped in clear water it would be difficult to observe the picture coming out, especially on copper. To overcome this difficulty the water must be tinged with some aniline color; aniline red or violet, which are soluble in water, answers the purpose very well. Enough of the dye must be dissolved in the water to give it a tolerably deep color. So soon as the plate is plunged into this liquid the albumen not acted on by light is dissolved, while the insoluble parts are colored by absorbing the dye, so that the metal is exposed in the lines against a red or violet ground, according to the color of the dye used.

When the drawing comes out quite perfect, and a complete copy of the original, the plate with the image on it is allowed to dry either of its own accord, or by submitting it to a gentle heat. So soon as it is dry it is etched, and this is done by means of a solution of perchloride of iron in alcohol. Both alcohol and iron perchloride will coagulate albumen; their action, therefore, on the image will not be injurious, since they will harden the remaining albumen still further. But to get the full benefit of this, the alcohol and the iron perchloride must both be free from water; it is therefore advisable to use the salt in crystals which have been thoroughly dried, and the alcohol of a strength of 95.

The following is the formula:

Perchloride of iron, well dried 50 gr. Alcohol at 95 100 "

This solution must be carefully filtered so as to get rid of any deposit which may form, and must be preserved in a well-corked bottle, when it will keep for a long time. The plate is first coated with a varnish of bitumen of Judea on the edges (if those parts are not already covered with albumen) and on the back, so that the etching liquid can only act on the lines to be engraved. It is then placed, with the side to be engraved downwards, in a porcelain basin, into which a sufficient quantity of the solution of perchloride of iron is poured, and the liquid is kept stirred so as to renew the portion which touches the plate; but care must be taken not to touch with the brush the parts where there is albumen remaining. The length of time that the etching must be continued depends on the depth required to be given to the engraving; generally a quarter of an hour will be found to be sufficient. Should it be thought desirable to extend the action over half an hour, the lines will be found to have been very deeply engraved. When the etching is considered to have been pushed far enough, the plate must be withdrawn from the solution, and washed in plenty of water; it must then be forcibly rubbed with a cloth so as to remove all the albumen, and after it has been polished with a little pumice, the engraving is complete.

It will be seen that this process may be used with advantage instead of that of photo-engraving with bitumen, in cases where it is not advisable to use acids. One of my friends, Mr. Fisch, suggests the plan—which seems to deserve a careful investigation—of combining this process with that where bitumen is employed; it would be done somewhat in the following way. The plate of metal would be first coated evenly with bitumen of Judea on the turning table, and when the bitumen is quite dry, it should be again coated with albumen in the manner as described above. In full sunlight the exposure need not exceed a minute in length; then the plate would be laid in colored water, dried, and immersed in spirits of turpentine. The latter will dissolve the bitumen in all the parts where it has been exposed by the removal of the albumen not rendered insoluble by the action of light. But it remains to be seen whether the albumen will not be undermined in this method; therefore, before recommending the process, it ought to be thoroughly studied. The metal is now exposed in all the parts that have to be etched, while all the other parts are protected by a layer of bitumen coated with coagulated albumen. Hence we may employ as mordant water acidulated with 3, 4, or 5 per cent. of nitric acid, according as it is required to have the plate etched with greater or less vigor.

By following the directions above given, any one wishing to adopt the process cannot fail of obtaining good results, One of its greatest advantages is that it is within the reach of every one engaged in printing operations.—Photo News.

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MERIDIAN LINE.

[Footnote: From Proceedings of the Association of County Surveyors of Ohio, Columbus, January, 1882.]

The following process has been used by the undersigned for many years. The true meridian can thus be found within one minute of arc:

Directions.—Nail a slat to the north side of an upper window—the higher the better. Let it be 25 feet from the ground or more. Let it project 3 feet. Kear the end suspend a plumb-bob, and have it swing in a bucket of water. A lamp set in the window will render the upper part of the string visible. Place a small table or stand about 20 feet south of the plumb-bob, and on its south edge stick the small blade of a pocket knife; place the eye close to the blade, and move the stand so as to bring the blade, string, and polar star into line. Place the table so that the star shall be seen very near the slat in the window. Let this be done half an hour before the greatest elongation of the star. Within four or five minutes after the first alignment the star will have moved to the east or west of the string. Slip the table or the knife a little to one side, and align carefully as before. After a few alignments the star will move along the string—down, if the elongation is west; up, if east. On the first of June the eastern elongation occurs about half-past two in the morning, and as daylight comes on shortly after the observation is completed, I prefer that time of year. The time of meridian passage or of the elongation can be found in almost any work on surveying. Of course the observer should choose a calm night.

In the morning the transit can be ranged with the knife blade and string, and the proper angle turned off to the left, if the elongation is east; to the right, if west.

Instead of turning off the angle, as above described, I measure 200 or 300 feet northtward, in the direction of the string, and compute the offset in feet and inches, set a stake in the ground, and drive a tack in the usual way.

Suppose the distance is 250 feet and the angle 1 40', then the offset will be 7,271 feet, or 7 feet 3 inches. A minute of arc at the distance of 250 feet is seven-eighths of an inch; and this is the most accurate way, for the vernier will not mark so small a space accurately.

ANGLE OF ELONGATION.

This should be computed by the surveyor for each observation. The distance between the star and the pole is continually diminishing, and on January 1, 1882, was 1 18' 48".

There is a slight annual variation in the distance. July 1, 1882, it will be 1 19' 20". If from this latter quantity the observer will subtract 16" for 1883, and the same quantity for each succeeding year for the next four or five years, no error so great as one-quarter of a minute will be made in the position of the meridian as determined in the summer months. If winter observations are made, the distance in January should be used. The formula for computing the angle of elongation is easily made by any one understanding spherical trigonometry, and is this:

R x sin. Polar dist. ——————————- = sin. of angle of elongation. cos. lat.

As an example, suppose the time is July, 1882, and the latitude 40. Then the computation being made, the angle will be found to be 1 43' 34". A difference of six minutes in the latitude will make less than 10" difference in the angle, as one can see by trial. Any good State or county map will give the latitude to within one or two miles—or minutes.

The facts being as here stated, the absurdity of the Ohio law, concerning the establishment of county meridians, becomes apparent. The longitude has nothing at all to do With the meridian; and a difference of six miles in latitude makes no appreciable error in the meridian established as here suggested, whereas the statute requires the latitude within one half a second, which is fifty feet. There are some other things, besides the ways of Providence, which may be said to be "past finding out." It is not probable that a surveyor would err so much as three miles in his latitude, but should he do so, then the error in his meridian line, resulting from the mistake, will be five seconds, and a line one mile long, run on a course 5" out of the way, will vary but an inch and a half from the true position. Surveyors well know that no such accuracy is attainable. R. W. McFARLAND,

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ELECTRO-MANIA.

By W. MATTIEU WILLIAMS.

A history of electricity, in order to be complete, must include two distinct and very different subjects: the history of electrical science, and a history of electrical exaggerations and delusions. The progress of the first has been followed by a crop of the second from the time when Kleist, Muschenbroek, and Cuneus endeavored to bottle the supposed fluid, and in the course of these attempts stumbled upon the "Leyden jar."

Dr. Lieberkuhn, of Berlin, describes the startling results which he obtained, or imagined, "when a nail or a piece of brass wire is put into a small apothecary's phial and electrified." He says that "if, while it is electrifying, I put my finger or a piece of gold which I hold in my hand to the nail, I receive a shock which stuns my arms and shoulders." At about the same date (the middle of the last century), Muschenbroek stated, in a letter to Raumur, that, on taking a shock from a thin glass bowl, "he felt himself struck in his arms, shoulders, and breast, so that he lost his breath, and was two days before he recovered from the effects of the blow and the terror" and that he "would not take a second shock for the kingdom of France." From the description Of the apparatus, it is evident that this dreadful shock was no stronger than many of us have taken scores of times for fun, and have given to our school-follows when we became the proud possessors of our first electrical machine.

Conjurers, mountebanks, itinerant quacks, and other adventurers operated throughout Europe, and were found at every country fair and fete displaying the wonders of the invisible agent by giving shocks and professing to cure all imaginable ailments.

Then came the discoveries of Galvani and Volta, followed by the demonstrations of Galvani's nephew Aldini, whereby dead animals were made to display the movements of life, not only by the electricity of the Voltaic pile, but, as Aldini especially showed, by a transfer of this mysterious agency from one animal to another.

According to his experiments (that seem to be forgotten by modern electricians) the galvanometer of the period, a prepared frog, could be made to kick by connecting its nerve and muscle with muscle and nerve of a recently killed ox, with, or without metallic intervention.

Thus arose the dogma which still survives in the advertisements of electrical quacks, that "electricity is life," and the possibility of reviving the dead was believed by many. Executed criminals were in active demand; their bodies were expeditiously transferred from the gallows or scaffold to the operating table, and their dead limbs were made to struggle and plunge, their eyeballs to roll, and their features to perpetrate the most horrible contortions by connecting nerves with one pole, and muscles with the opposite pole of a battery.

The heart was made to beat, and many men of eminence supposed that if this could be combined with artificial respiration, and kept up for awhile, the victim of the hangman might be restored, provided the neck was not broken. Curious tales were loudly whispered concerning gentle hangings and strange doings at Dr. Brookes's, in Leicester Square, and at the Hunterian Museum, in Windmill Street, now flourishing as "The Caf de l'Etoile." When a child, I lived about midway between these celebrated schools of practical anatomy, and well remember the tales of horror that were recounted concerning them. When Bishop and Williams (no relation to the writer) were hanged for burking, i.e., murdering people in order to provide "subjects" for dissection, their bodies were sent to Windmill Street, and the popular notion was that, being old and faithful servants of the doctors, they were galvanized to life, and again set up in their old business.

It is amusing to read some of the treatises on medical galvanism that were published at about this period, and contrast their positive statements of cures effected and results anticipated with the position now attained by electricity as a curative agent.

Then came the brilliant discoveries of Faraday, Ampre, etc., demonstrating the relations between electricity and magnetism, and immediately following them a multitude of patents for electro-motors, and wild dreams of superseding steam-engines by magneto-electric machinery.

The following, which I copy from the Penny Mechanic, of June 10, 1837, is curious, and very instructive to those who think of investing in any of the electric power companies of to-day: "Mr. Thomas Davenport, a Vermont blacksmith, has discovered a mode of applying magnetic and electro-magnetic power, which we have good ground for believing will be of immense importance to the world." This announcement is followed by reference to Professor Silliman's American Journal of Science and the Arts, for April, 1837, and extracts from American papers, of which the following is a specimen: "1. We saw a small cylindrical battery, about nine inches in length, three or four in diameter, produce a magnetic power of about 300 lb., and which, therefore, we could not move with our utmost strength. 2. We saw a small wheel, five-and-a-half inches in diameter, performing more than 600 revolutions in a minute, and lift a weight of 24 lb. one foot per minute, from the power of a battery of still smaller dimensions. 3. We saw a model of a locomotive engine traveling on a circular railroad with immense velocity, and rapidly ascending an inclined plane of far greater elevation than any hitherto ascended by steam-power. And these and various other experiments which we saw, convinced us of the truth of the opinion expressed by Professors Silliman, Renwick, and others, that the power of machinery may be increased from this source beyond any assignable limit. It is computed by these learned men that a circular galvanic battery about three feet in diameter, with magnets of a proportionable surface, would produce at least a hundred horse-power; and therefore that two such batteries would be sufficient to propel ships of the largest class across the Atlantic. The only materials required to generate and continue this power for such a voyage would be a few thin sheets of copper and zinc, and a few gallons of mineral water."

The Faure accumulator is but a very weak affair compared with this, Sir William Thomson notwithstanding. To render the date of the above fully appreciable, I may note that three months later the magazine from which it is quoted was illustrated with a picture of the London and Birmingham Railway Station displaying a first-class passenger with a box seat on the roof of the carriage, and followed by an account of the trip to Boxmoor, the first installment of the London and North-Western Railway. It tells us that, "the time of starting having arrived, the doors of the carriages are closed, and, by the assistance of the conductors, the train is moved on a short distance toward the first bridge, where it is met by an engine, which conducts it up the inclined plane as far as Chalk Farm. Between the canal and this spot stands the station-house for the engines; here, also, are fixed the engines which are to be employed in drawing the carriages up the inclined plane from Euston Square, by a rope upwards of a mile in length, the cost of which was upwards of 400." After describing the next change of engines, in the same matter of course way as the changing of stage-coach horses, the narrative proceeds to say that "entering the tunnel from broad daylight to perfect darkness has an exceedingly novel effect."

I make these parallel quotations for the benefit of those who imagine that electricity is making such vastly greater strides than other sources of power. I well remember making this journey to Boxmoor, and four or five years later traveling on a circular electro-magnetic railway. Comparing that electric railway with those now exhibiting, and comparing the Boxmoor trip with the present work of the London and North-Western Railway, I have no hesitation in affirming that the rate of progress in electro-locomotion during the last forty years has been far smaller than that of steam.

The leading fallacy which is urging the electro-maniacs of the present time to their ruinous investments is the idea that electro-motors are novelties, and that electric-lighting is in its infancy; while gas-lighting is regarded as an old, or mature middle-aged business, and therefore we are to expect a marvelous growth of the infant and no further progress of the adult.

These excited speculators do not appear to be aware of the fact that electric-lighting is older than gas-lighting; that Sir Humphry Davy exhibited the electric light in Albemarle Street, while London was still dimly lighted by oil-lamps, and long before gas-lighting was attempted anywhere. The lamp used by Sir Humphry Davy at the Royal Institution, at the beginning of the present century, was an arrangement of two carbon pencils, between which was formed the "electric arc" by the intensely-vivid incandescence and combustion of the particles of carbon passing between the solid carbon electrodes. The light exhibited by Davy was incomparably more brilliant than anything that has been lately shown either in London, or Paris, or at Sydenham. His arc was four inches in length, the carbon pencils were four inches apart, and a broad, dazzling arch of light bridged the whole space between. The modern arc lights are but pygmies, mere specks, compared with this; a leap of 1/3 or 1/4 inch constituting their maximum achievement.

Comparing the actual progress of gas and electric lighting, the gas has achieved by far the greater strides; and this is the case even when we compare very recent progress.

The improvements connected with gas-making have been steadily progressive; scarcely a year has passed from the date of Murdoch's efforts to the present time, without some or many decided steps having been made. The progress of electric-lighting has been a series of spasmodic leaps, backward as well as forward.

As an example of stepping backward, I may refer to what the newspapers have described as the "discoveries" of Mr. Edison, or the use of an incandescent wire, or stick, or sheet of platinum, or platino-iridium; or a thread of carbon, of which the "Swan" and other modern lights are rival modifications.

As far back as 1846 I was engaged in making apparatus and experiments for the purpose of turning to practical account "King's patent electric light," the actual inventor of which was a young American, named Starr, who died in 1847, when about 25 years of age, a victim of overwork and disappointment in his efforts to perfect this invention and a magneto-electric machine, intended to supply the power in accordance with some of the "latest improvements" of 1881 and 1882.

I had a share in this venture, and was very enthusiastic until after I had become practically acquainted with the subject. We had no difficulty in obtaining a splendid and perfectly steady light, better than any that are shown at the Crystal Palace.

We used platinum, and alloys of platinum and iridium, abandoned them as Edison did more than thirty years later, and then tried a multitude of forms of carbon, including that which constitutes the last "discovery" of Mr. Edison, viz., burnt cane. Starr tried this on theoretical grounds, because cane being coated with silica, he predicted that by charring it we should obtain a more compact stick or thread, as the fusion of the silica would hold the carbon particles together. He finally abandoned this and all the rest in favor of the hard deposit of carbon which lines the inside of gas-retorts, some specimens of which we found to be so hard that we required a lapidary's wheel to cut them into the thin sticks.

Our final wick was a piece of this of square section, and about 1/8 of an inch across each way. It was mounted between two forceps—one holding each end, and thus leaving a clear half-inch between. The forceps were soldered to platinum wires, one of which passed upward through the top of the barometer tube, expanded into a lamp glass at its upper part. This wire was sealed to the glass as it passed through. The lower wire passed down the middle of the tube.

The tube was filled with mercury and inverted over a cup of mercury. Being 30 inches long up to the bottom of the expanded portion, or lamp globe, the mercury fell below this and left a Torricellian vacuum there. One pole of the battery, or dynamo-machine, was connected with the mercury in the cup, and the other with the upper wire. The stick of carbon glowed brilliantly, and with perfect steadiness.

I subsequently exhibited this apparatus in the Town-hall of Birmingham, and many times at the Midland Institute. The only scientific difficulty connected with this arrangement was that due to a slight volatilization of the carbon, and its deposition as a brown film upon the lamp glass; but this difficulty is not insuperable.—Knowledge.

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ACTION OF MAGNETS UPON THE VOLTAIC ARC.

The action of magnets upon the voltaic arc has been known for a long time past. Davy even succeeded in influencing the latter powerfully enough in this way to divide it, and since his time Messrs. Grove and Quet have studied the effect under different conditions. In 1859, I myself undertook numerous researches on this subject, and experimented on the induction spark of the Ruhmkorff coil, the results of these researches having been published in the last two editions of my notes on the Ruhmkorff apparatus.



These researches were summed up in the journal La Lumire Electrique for June 15, 1879. Recently, Mr. Pilleux has addressed to us some new experiments on the same subject, made on the voltaic arc produced by a De Meritens alternating current machine. Naturally, he has found the same phenomena that I had made known; but he thinks that these new researches are worthy of interest by reason of the nature of the arc in which he experimented, and which, according to him, is of a different nature from all those on which, up to the present time, experiments have been made. Such a distinction as this, however, merits a discussion.

With the induction spark, magnets have an action only on the aureola which accompanies the line of fire of the static discharge; and this aureola, being only a sort of sheath of heated air containing many particles of metal derived from the rheophores, represents exactly the voltaic arc.



Moreover, although the induced currents developed in the bobbin are alternately of opposite direction, the galvanometer shows that the currents that traverse the break are of the same direction, and that these are direct ones. The reversed currents are, then, arrested during their passage; and, in order to collect them, it becomes necessary to considerably diminish the gaseous pressure of the aeriform conductor interposed in the discharge; to increase its conductivity; or to open to the current a very resistant metallic derivation. By this latter means, I have succeeded in isolating, one from the other, in two different circuits, the direct induced currents and the reversed induced ones. As only direct currents can, in air at a normal pressure, traverse the break through which the induction spark passes, the aureola that surrounds it may be considered as being exactly in the same conditions as a voltaic arc, and, consequently, as representing an extensible conductor traversed by a current flowing in a definite direction. Such a conductor is consequently susceptible of being influenced by all the external reactions that can be exerted upon a current; only, by reason of its mobility, the conductor may possibly give way to the action exerted upon the current traversing it, and undergo deformations that are in relation with the laws of Ampre. It is in this manner that I have explained the different forms that the aureola of the induction spark assumes when it is submitted to the action of a magnet in the direction of its axial line, or in that of its equatorial line, or perpendicular to these latter, or upon the magnetic poles themselves.