this new branch of manufacture, which is already carried on so successfully in Europe.

In the manufacture of iron with blast furnaces there is formed more or less of a dark-colored glass known as slag or scoria. This refuse matter accumulates around furnaces, and must be carried away in order to get rid of it. It is almost as great a nuisance as the coal dust of our anthracite coal mines.

Within three or four years the manufacture of articles made from slag has been carried on successfully in England in the iron districts. In the Cleveland district alone from three to four million of tons of slag are made annually. Bricks, paving stones and slabs, concrete panels, tiles, etc., are now made from this material. I believe it capable of being introduced as a building material in many ways, and that ready means for its application would soon be discovered should its manufacture be carried on in this country. In England we read of an iron manufacturer offering to furnish to any glass-maker who wishes to establish glass works in his neighborhood three million of tons of slag for nothing. Doubtlessly, there would be plenty of our iron-makers who would show as much generosity to any one wishing to embark in this business.

Slag-glass, in its natural state, is too dark to be applied to the purposes for which ordinary white glass is used, but it can readily be made useful in all articles of cheap and ordinary use where slightly colored glass is not objectionable. As a competitor against ordinary glass, slag-glass has a great advantage in its low price, since the larger part of its ingredients could be had for nothing.

In connection with blast furnaces it would be an easy matter to erect glass works, and, by proper arrangements, to transfer the hot slag into glass furnaces, and thereby retain a large part of the heat already developed. Should the slag not contain a sufficient quantity of silica, an additional amount of sand might be added. Should it be too silicious, and thereby produce a too hard and brittle glass, the required quantity of sulphate of soda might be added to produce a glass of the ordinary conditions. The installation of the furnaces might be so arranged as to utilize some of the waste gases of the blast furnaces. The furnaces could be built without pots, and tank furnaces, similar to those used in the iron manufacture, might be used with slight modifications, or furnaces in the style of Siemens’s continuous melting plan. With the exception of the color, this glass could be produced in all degree of hardness and softness

suitable for different purposes. For the terracotta articles now so extensively used in Europe those made with slag glass could be substituted, and so made and ornamented as to be a vastly cheaper substitute.

The utilization of slag in another direction has already been introduced in this country. At the Clove Furnace, Greenwood Iron Works, Orange County, New York, a manufactory has been started for the production of mineral wool, so called, used as a non-conducting substance for lining roofs, protection against fire, etc. The slag in its molten state is drawn from the blast furnace and emptied into a tank carried upon a small wheel truck, or car. The car runs upon a railway and is carried opposite the wool-house, which is lined inside with thin sheet-iron. There are two floors, but the upper one does not run the whole distance of the building. The operation is as follows: The car filled with hot glass is brought opposite the apertures in the wool-house, the glass is allowed to drop upon a runner in a small stream, steam is conveyed under the runner, and as the glass drops it is met by the jet of steam, which blows it with great force inside of the wool-house in very thin filaments. In order to obtain proper filaments the glass must not be too liquid, but of a sufficient degree of plasticity only. The effect of the steam or air jet is to detach from the flowing stream a small hot shot, which furnishes the basis for the filament; the smaller the shot the smaller the filaments. It has been found that by regulating the heat of the flowing stream and the strength of the steam jet, the shot remaining may be reduced to less than one-sixteenth of an inch and is not necessary to be separated from the wool, as it does not impair its effect. The lightest wool, carried to the upper floor, is entirely free from the residuary balls.

This mineral wool being non-combustible, and of very fine texture, answers the conditions for a good non-conductor of heat. It has been applied as a coating for steam-boilers, engine cylinders, steam-domes, pipes, a lining for ice-houses, brewers’ vaults, refrigerators, etc. It should be applied loose, without crushing, as although it is perfectly elastic yet it is apt to be broken in small pieces which easily escape confinement. This wool has received an extensive application in England under the name of slag-wool; and in Germany, where it is known as silicate cotton, a cubic foot costs from 10 to 20 cents, according to fineness of filaments.

Fine glass-wool or glass-cotton is made in Austria in very fine white and colored filaments, and is used for the

manufacture of cloth, laces, ladies’ fancy articles, etc. I do not believe, however, that this glass is capable of a very wide range of application, since it is subject to break into short fibers whenever it is submitted to a certain pressure while folded. A quantity of this glass wool I brought over from the Exhibition and put away in an envelope, on being opened, shows a pretty large percentage of white, short, broken fibers settled at the bottom. This would indicate that glass, even in such an attenuated condition, still retains to a certain degree the peculiar brittleness of all glass. In the weaving process a large proportion of these fibers must be lost, and a fabric folded and put under pressure could not resist the deterioration of such a treatment, and would show a number of broken fibers in the folded places.

Mechanical tools.

While Europe, to attain perfection in manufacturing, has had to depend upon the superior skill of workmen, in this country, being entirely deprived of skilled labor in the beginning, we have had to depend upon the substitute of mechanical devices. The inventive genius of our people. proves the old adage, “Necessity is the mother of invention” to be a true one. Necessity has pointed out the want to be supplied. This is one-half of the invention, as, when we know what we want, we can always find mechanical means to accomplish our end. The inventive genius of this country has also been greatly fostered by our wise patent laws. The question of self-interest or profit is a factor in inventing which cannot be ignored. It is to be hoped that the attempts which have been made lately to procure national legislation to use by force the property of inventors and to deprive them of its control will be frowned down by all those who have the prosperity of this country at heart, and who have a well-defined idea of the sacred right of property, be it patent property or any other.

In glass-making, as in other industries, the scarcity of skilled labor drove our people to devise means for accomplishing work without its aid. We were naturally driven to machinery. To obviate hand-blowing, a process which is very difficult to master, shaping with press and iron molds was substituted. The beneficial results of this invention are incalculable. It placed our manufacturers in a position to make regular and cheap wares, while skilled labor became no longer necessary. The simplicity of the operation of pressing glass was such that in a very

short time men could be trained to perform the work. It does not require much knowledge to train men to gather glass, drop it into a mold, and cut off a sufficient quantity. The glass now being in the iron mold, a plunger is made to press the plastic mass, and in solidifying, by cooling, the objects retain the form of the mold and the plunger. A simpler operation can scarcely be devised. This invention was the royal road to success. Then came improvements fast and thick in combinations of the different pieces of molds, improvements in presses, and tools for holding the pieces while being fire-polished.

One of the most important inventions in pressing, one which in my opinion was the foundation of goblet-pressing, is the cup-shape given to the foot in the mold instead of pressing it flat as in the finished shape. This invention is evidently based upon the principle that in flowing sharp angles should be avoided and curves substituted. By this means glass is made to flow gradually in easy curves and the wrinkling of surfaces is avoided. It is a principle which should never be forgotten by inventors — a principle of the utmost importance to produce smooth, clear, and even surfaces. One of the defects of pressed glass, and which shows its inferiority to cut glass, is the difficulty of producing and maintaining sharp angles. If we succeed in obtaining these angles to our satisfaction in the mold, in fire-polishing and in reheating we are very apt to lose them. The heat taking effect at first upon the thinnest parts, the angles, softens them and the sharpness is lost. To obviate this to a certain degree, it has been imagined to so shape the iron molds that the angles stand in bolder reliefs, viz, the angles are lengthened in the molds. It will be seen that if the heat softens these angles they yet stand enough in relief to give marked and distinct outlines.

To obviate the uneven surface of flat or fluted articles, the molds have been constructed so as to make the flutes deeper in the middle, and with angles slanting towards this point. It will be seen that a flute composed of two angles tending to the center is not as likely to show defects as if it was of a plain flat surface. Although these improvements have accomplished much towards attaining perfection, pressed glass will never attain the beauty of cut glass.

Another defect of pressed ware is the marks left on the glass at points where the different pieces of the mold are joined together. However skillfully the molds may be made, in course of time the joints will work loose through the expansion and contraction of the metal, and the glass

will gradually be pressed in the loose spaces of the joints, thereby imprinting on the surface of the articles ribs or sharp threads, marring the beauty of the work. Among the notable improvements made in molds and presses, the following are some of the more particularly worthy of notice:

To obviate the mold-marks, molds have been made to open at such places and parts of the design that they can scarcely be seen — in goblets, for instance, the marks are left on the edges of angles; also in combining the molds so as to leave the marks on the edge of the scallop made by the top of flutes in a goblet or tumbler.

Molds have been made with different mechanical devices to operate a plunger above and another below, in order to form two cavities, such as the cup-shaped foot and the bowl of a goblet. Letters, monograms, and ornaments have been made by introducing lateral pieces in molds containing the proper designs. These pieces are changeable, and the same shaped article may be made having different lettering, etc. Curved tubes and glass slippers have been made by giving the plunger a descending curvilinear instead of a vertical motion.

Lamps, goblets, and similar articles have been made by first pressing the foot, then blowing the head or body upon it, placing the foot in suitable bearings to connect the two together. The upper part may either be blown in a mold or previously shaped with tools and made to adhere while the glass is hot. Goblets are also made by first pressing the bowl and stem, inverting the goblet, then pressing the foot upon the stem. When the pieces are rotated in the mold the foot is placed upon a pivoted rotating form.

Pieces which are wider at top than bottom cannot be pressed in the usual way, since the plunger is always a cone, which must be pushed into the mold and withdrawn. These pieces are pressed bottom up, and lips or projections sufficient to form the bottom are formed in the mold. The piece, after being pressed, is withdrawn from the mold, the bottom is heated, and with a tool the lips are brought together to close it up.

Pieces requiring to have designs pressed in the side which would prevent them from coming out of a mold made in one piece, have been made by having sliding lateral pieces placed in the side of the mold. These pieces are moved forward and withdrawn by suitable means, leaving the piece free to come out of the mold. Improvements in the same order have also been made for molding handles or

forming holes in handles by means of sliding pieces, which are pushed through the side of the mold and withdrawn to take the pieces out.

When articles are so shaped on the outside as to present a few protuberances, and it is not thought advisable to open the mold, in order to avoid mold-marks the molds are so combined that the protuberances are made by sliding lateral pieces, which, when withdrawn, allow the object to be taken out of the mold.

In shaping tools for mouths of bottles, jars, etc., we have several combinations to produce effects not to be obtained by hand.

The ordinary neck shaping tool for making bottle necks is made of a central pivoted piece to form the inside of the neck and two stationary pieces to form the outside. Sometimes the necks of certain jars require to have a screw shape molded in the inside. To accomplish this the central piece of the shaping tool is made screw-like, and the two outside rubbing pieces of the desired shape, according to the style of jar. It is sometimes desired to form cavities or projections in or on the necks of jars; this is usually done by having laterally moving pieces attached to the inside former or the outside jaws, as the case may be; these sliding pieces are operated when the tool is at rest after shaping the neck. In the same order of tools may be classed the formers for making the pouring lips on the neck of cruets. These tools have suitably shaped jaws, which are pressed against the neck to give it the proper slant. It is also desirable sometimes to make holes in the side of a jar or a jar cover. This is done by having metallic pegs placed on the outside jaws, which are pushed in through the metal to pierce it. The middle piece fitting the inside of the bottle neck in some of the forming tools is so made that at the time of entering it is very narrow, but is gradually widened by forcing apart the two sections of which it is made.

Molasses cans are now made with a glass pouring lip at top and slanting channel to run the dripped molasses into the can again, the whole being closed by a metallic cover. To form the glass lip the piece is molded upside down, with bottom flaps to close up the can. In this position the can forms a cone; the plunger can therefore be pushed in and withdrawn with facility. The bottom of the mold is made of a suitable shape, and the plunger is so combined with the bottom piece that the opening in the mouth of the can is made at the same time as the body is pressed. This is accomplished by the combination of a movable bottom

with sharp angles, so that when the plunger passes the sharp angles, and fitting close against these, the bottom piece of glass is cut off as the mold bottom recedes. By this device clock frames, decanters, pipes open at both ends, etc., are also made.

Handles have been pressed in separate molds and the body of the object subsequently blown upon them in another mold, the operation cementing the two together while the metal is hot. Small hand lamps have been blown in ordinary iron molds, and the handle formed by allowing hot plastic glass to descend in a channel at the side of the mold until the two ends meet the bowl of the lamp and become cemented to it while hot.

Lamps have been made with the foot and bowl fastened together by means of a metallic ferrule screwed over the two parts. In order to obtain the screw-pegs at the bottom of the lamp bowl and the top of the foot, molds have been devised so as to give to the bottom piece of the mold a rotary motion to withdraw it from the formed peg. This style of forming screws is to avoid the mold-marks which are made when the mold opens, but, in my opinion, it is complicating the mold to obtain but a slight advantage.

In telegraph insulators, however, requiring a hollow screw, the rotating retreating bottom piece becomes a necessity, as the plunger cannot be pushed and withdrawn owing to the projecting screw threads.

Lamps are blown with metallic pegs or collars embedded in the glass. The pegs are previously heated, set into recesses in the molds, and the lamp blown over it. I do not think this a very good improvement, for the rate of expansion of iron or metal is so different from that of glass that it frequently happens that this inequality causes the glass to crack.

Round glass balls used for casters or for shooting at are now made by using molds containing several sections, which leave only a small connection of glass between each ball. A rod of hot glass is prepared, then rolled lengthwise over the different sections of the mold; the glass is gradually shaped into several balls, slightly attached together by thin connections; these are easily severed, and the balls are then perfectly round.

Glass chandeliers in imitation of their costlier brothers in cut glass are now pressed and molded at a very low cost. To press these chandeliers iron molds of the proper shape are used, and the plunger is as usual made of corresponding shape. To make the holes for the mounting pipes and the

gas cocks the plunger carries lengthened pegs which fit closely into corresponding holes in the mold, and as the plunger descends the holes are cut out. These chandeliers are also blown instead of pressed. The blowing molds are of iron, properly shaped; the pieces are blown as usual, with a blow-over piece, which is detached by any of the well-known ways. This style of chandeliers consists of a series of blown or pressed pieces, which are mounted on metallic gas pipes and fastened at the ends. It will readily be seen that this mode of manufacture cheapens the cost very materially.

Molds have been made with movable bottoms to allow the surplus glass, when in excess, to force the latter down, thereby increasing the thickness of the bottom piece. In order to equalize the distribution of heat in iron molds, they have been so made that by varying the thickness of the different parts the cooling and heating become equalized.

To manufacture battery jars, having tubular formations running from top to bottom, a ring plate is used, having two mandrels attached to it and falling into suitable recesses in the bottom of the mold. This ring plate being adjusted in the mold, the plunger is made to come down, and by its pressure the hot glass is made to run around the mandrels while the jar itself is being formed. The plunger having been withdrawn, the mandrel plate is pulled out, and the tubular cavities now appear properly formed.

Articles wider at the bottom than at the top, on the outside may be pressed by introducing between the outer shell of the mold and the plunger a cylinder tapering wider from top to bottom. The inside of the article must of course be made tapering downward towards the center, so that the plunger may be withdrawn. It will be understood that the plunger having been withdrawn, the article being wider at the bottom than at the top, it cannot yet be taken out of the mold. To do so the intermediate cylinder is withdrawn, and the article is now left perfectly free to come out.

A combination mold has been made to press molasses cans and such articles which are wider in the middle than at both ends. It is plain to be seen that to make such cans no plunger can be used to press the article all the way down on account of the belly of the can. To obviate this inconvenience, molds have been made of several pieces, as follows: The upper part of the can, consisting of the neck and handle, is pressed in a mold having a movable bottom piece which is run up past the belly of the can, but only to a proper distance, so that the bottom may be left thick enough

to furnish sufficient material to form the body of the can. The plunger is provided with air passages to admit of the body being blown. The lower part of the mold, through which the bottom piece ascends, is made of the proper shape to form the body and bottom. The operation is as follows: The mold-bottom piece is run up to its proper height, glass is introduced in the mold, the plunger is brought down, thereby forming the neck and handle of the can and a thick glass bottom. The mold bottom-piece is now lowered, the thick glass bottom is dilated and made to fit the lower mold by the pressure of the air sent through the plunger, thereby finishing the piece.

Another mode of manufacturing molasses cans consists in pressing the neck and handle in a separate mold, making the inside of the neck slightly tapering upwards. The body of the can is then blown in the usual form of mold, and the two parts are cemented by running the neck piece of the body into the pressed neck, and cement is then poured into the space left between the two.

In order to facilitate the molding of plain blown articles, molds are mounted on revolving platforms, and, by a suitable combination of levers, are made to open and shut, even when the platform is revolving. The molds may be made of a series of rollers shaped so as to make the desired article, or of sections of molds, or two solid halves. The mechanism for revolving the mold-bearer may be cogwheels or other gearing.

It is sometimes desirable to make certain articles with openings, such as on the top of a lamp head, to leave an opening for filling the lamp. These holes, or openings, are produced as follows: After the lamp head has been properly shaped, a small quantity of hot glass is dropped upon the lamp top, which has been previously reheated. The lump and the top of the lamp being now sufficiently plastic, a tool somewhat in the style of those for forming bottle necks is used. This tool consists of an annular piece, which is brought over the hot lump of glass and shapes the outside. While this annular piece is in contact, a central pin is pushed forward and pierces the glass, thus producing the opening. Should it be wanted to cement a cap over the opening, the shaping tool is provided with two levers having ends properly shaped for the purpose. These ends are pressed on the outside of the tube and form recesses.

Many articles, after being molded, pressed, or blown, require to be held by the foot for fire-polishing, or giving them the final shape. It has been customary, heretofore, to fix the

foot to a piece of hot glass on the end of an iron rod, and the finishing is then put on. To detach the pieces it is necessary to part the two by giving a sharp blow on the iron rod. The foot frequently retains pieces of broken glass, which must be removed by grinding. To avoid this, spring “snaps” are used. These consist of a couple of jaws mounted on springs, so that they can open and shut. These jaws are fastened at the end of an iron rod, like a blow-pipe.

If a goblet is to be finished, the operation is as follows: The jaws are made to open, and, by the action of the springs, they immediately close upon the foot and hold the goblet ready to be finished. Sometimes these jaws are so arranged that they can be set forward and back a,nd fastened by screws. This admits of holding a large variety of pieces of different sizes.

When pressing glass continuously for a long time, the molds often get heated too high, and in this state glass is very apt to stick to them. This inconvenience is now done away with by a system of blowing air into the molds. By means of a revolving fan, or other device, and tin pipes ar­ranged around the furnace, a continuous stream of air is furnished. India-rubber pipes are attached to the tin pipes at suitable places. By means of these pipes, after each pressing, or as often as necessary, a stream of air is sent inside of the mold, thereby cooling it. The air circulating in the pipes may also be used for ventilation and cooling the glasshouse.

Of late, attempts have been made to use presses for pressing glass by steam or compressed air. One of these presses has a set of molds carried upon a revolving bed, and is operated by a presser like a hand-press. The power, however, is applied to the presser by means of an auxiliary steam engine, which is continually at work. Whenever an article is to be pressed, by suitable leverage the presser is forced down, then released, the bed-plate revolves far enough to bring another mold under the presser, and the operation is repeated as often as desired. Mechanism is attached and operated also by steam so as to push the pieces out of the mold after they are pressed. These are the principal features of the invention.

In the other press steam is replaced by compressed air contained in a reservoir, which may be filled by means of an air-compressing engine. The bed-plate carrying the molds has a rectilinear motion. When an article is to be pressed, the mold is brought under the presser; by means of suitable valves and pipes, air is sent to a cylinder piston carrying the

plunger. The pressure of the air forces the presser down into the mold, the valves are reversed, and the piston and presser fly back. A new mold is now under the plunger. The operation may be repeated as often as desired by simply opening and closing the air valves. In this press, as in the other, the pieces are forced out of the molds by rising plugs or bottoms. The different motions of this press are entirely automatic, with the exception of operating the air valves.

In order to form the air bubbles which are often seen in­side of solid pieces of glass, they have been pressed with cavities on the outside, and after being reheated they are closed by pressing the outside down with suitable tools, thus inclosing the air in the cavities.

In making chimneys many ingenious devices are now used. They are blown in metallic molds, having piercers attached to the bottom to open the lower part of the chimney. Sometimes, in order to have the chimneys cut at the proper height, creasers or cutters are added at suitable places in the mold, which, by rotating the piece, indent it sufficiently so that the superfluous parts may be broken off. Molds have been made with a base terminating in a very sharp angle. When the glass enters the mold the blower allows the glass to reach into the angular cavity, gently blows, and, when finishing, increases the force of his blowing, thereby spreading the glass at the bottom of the chimney against the thin, sharp base into a very thin sheet of glass, which can subsequently be taken off very easily. Chimneys are pressed in molds having knife-edges inserted at the bottom, thereby reducing very materially the thickness of the glass at that point. The piece remaining beyond the crease thus produced can be knocked off, leaving the chimney open at both ends.

The recent tendency of work in making chimneys is to have rotating tools of different shapes, and to present the article to be shaped against it. While the tool is rotating, the different branches composing it are made to expand to a definite size after having entered the article while folded to their smallest compass. Chimneys are open at the bottom and flared at the top by means of these devices. Many devices have been used in these tools, but they nearly all operate upon the expansion principle after having entered the article. Solid conical pieces have been used for flaring, some plain and others ribbed, but they are all more or less objectionable on account of creasing or twisting the glass by the large amount of friction produced. The most

successful flarers are those made of a few sectional branches revolving at a rapid rate.

The cupped feet of goblets are also opened by these flaring and opening tools. With the inside flaring or opening tools, jaws have been combined so as to form the outside, both revolving. By this means the mouths of bottles are shaped, as well as the extremities of chimneys, etc. These tools are supplanting the old hand shaping tools. In order to crimp chimneys sectional blades are added to flaring tools, so that when the flaring is finished they may be crimped by pushing the blades against the flared end. These crimping tools differ in shape, but are alike in principle.

The same style of forming tools has been made with revolving rollers placed on the end of a revolving shaft. The object to be shaped is placed between the opened rollers; by suitable mechanism these rollers are made to close, the roller shaft, revolving, causes the shaping rollers to revolve by their friction against the object. By giving different shapes to the shaping rollers different styles of goods may be made. The rollers have for object to avoid the great friction produced by solid or sectional molds, and are of the same nature as the revolving molds previously mentioned.

I have thus rapidly sketched the principal improvements made in mechanical tools for working glass. Many minor inventions have been made, but they are mostly modifications of other devices. Our aptitude to adapt machinery to our wants is as noticeable in glass-making as in other branches of industry. Many inventors, however, not being sufficiently acquainted with the peculiar properties of glass, have applied to its working combinations of machinery altogether impracticable. Glass, while hot, may be compared to plastic dough, and it is only in this state that it can be properly worked. Should it be too hot, it becomes too liquid and cannot be worked. In pressing, the plastic mass is forced up and fills the cavity between the plunger and the inner shell of the mold. Should the glass be too liquid it could not retain the shape given to it by the mold, and would fall down again. Should the mass be too cold the action of the plunger would be hard and imperfect, and the friction of the glass against the surfaces of the mold and plunger would cause wrinkles to appear upon the face of the pressed articles. Glass being worked in a plastic state, in order to get even and smooth surfaces abrupt angles should be avoided, since the plastic mass cannot pass a sharp curve without creasing its surface. In blowing articles, shaping with tools, or blowing in molds, should the

glass be too hot it cannot retain its shape; should it be too cold the shaping becomes difficult. Pieces requiring some time to finish them have to be reheated again and again until finished. This frequent, reheating and cooling has a tendency to produce devitrification, and the glass loses its transparency.

Having been the pioneers in pressing glass, we retain to this day the supremacy in this branch. European pressed glass cannot be compared with our productions, and, at the rate that mechanical inventions are applied to its working, we certainly should maintain our position over all other parts of the world. As in other branches of manufacture, patents have been issued for inventions possessing no novelties, and have led to litigations both costly and vexatious. With the custom in vogue in making appointments in our civil service this can scarcely be avoided. If examiners in our Patent Office were retained during good behavior, and not subject to political changes or removal to make places for new-found friends, we could reasonably hope to have an efficient corps, in which each man would be thoroughly posted in his own particular branch. With efficient examiners, holding their positions for life or during good behavior, there would be no inducement to do wrong, nor would patents be granted for inventions known to other persons better posted than themselves. A patent issued under the seal of the Patent Office and granted after examination by such a corps of clerks would be invaluable to inventors, and in many instances such a document would be a sufficient guarantee against the invasion of their rights. Whether we shall ever reach such a happy result in our civil service is for the people to decide. In a popular form of government what the people wish should be granted by our legislatures. The patent laws have done much towards fostering our industries, and inventors, as a class, have contributed much to our prosperity, besides pouring a large revenue into our national Treasury; they, therefore, would seem to have a right to ask the paternal care of the government.