Chapter II: Application of Light-Gas (9)

The annexed figures represent Mr. Ollerenshaw’s machine, now generally employed for ironing hats. _Fig._ 534. is the frame-work or standard upon which three of these lathes are mounted, as A, B, C. The lathe A is intended to be employed when the crown of the hat is to be ironed. The lathe B, when the flat top, and the upper side of the brim is ironed, and lathe C, when its under side is ironed; motion being given to the whole by means of a band passing from any first mover (as a steam-engine, water-wheel, &c.) to the drum on the main shaft _a a_. From this drum a strap passes over the rigger _b_, which actuates the axle of the lathe A. On to this lathe a sort of chuck is screwed, and to the chuck the block _c_ is made fast by screws, bolts, or pins. This block is represented in section, in order to shew the manner in which it is made, of several pieces held fast by the centre wedge-piece, as seen at _fig._ 535.

The hat-block being made to turn round with the chuck, at the rate of about twenty turns per minute, but in the opposite direction to the revolution of an ordinary turning lathe, the workman applies his hot iron to the surface of the hat, and thereby smooths it, giving a beautiful glossy appearance to the beaver; he then applies a plush cushion, and rubs round the surface of the hat while it is still revolving. The hat, with its block, is now removed to the lath B, where it is placed upon the chuck _d_, and made to turn in a horizontal direction, at the rate of about twenty revolutions per minute, for the purpose of ironing the flat-top of the crown. This lathe B moves upon an upright shaft _e_, and is actuated by a twisted band passing from the main shaft, round the rigger _f_. In order to iron the upper surface of the brim, the block _c_ is removed from the lathe, and taken out of the hat, when the block _fig._ 536. is mounted upon the chuck _d_, and made to turn under the hand of the workman, as before.

The hat is now to be removed to the lathe C, where it is introduced in an inverted position, between the arms _g g_ supporting the rim _h h_, the top surface of which is shewn at _fig._ 537. The spindle _i_ of the lathe turns by similar means to the last, but slower; only ten turns per minute will be sufficient. The workman now smooths the under side of the brim, by drawing the iron across it, that is from the centre outwards. The hat is then carefully examined, and all the burs and coarse hairs picked out, after which the smoothing process is performed as before, and the dressing of the hat is complete.

Messrs. Gillman and Wilson, of Manchester, obtained a patent, in 1823, for a peculiar kind of fabric to be made of cotton, or a mixture of cotton and silk, for the covering of hats and bonnets, in imitation of beaver. The foundation of the hat may be of felt, hemp, wool, which is to be covered, by the patent fabric. This debased article does not seem to have got into use; cotton, from its want of the felting property and inelasticity, being very ill-adapted for making hat-stuff.

A more ingenious invention of John Gibson, hatter, in Glasgow, consisting of an elastic fabric of whalebone, was made the subject of a patent, in June, 1824. The whalebone, being separated into threads no larger than hay stalks, is to be boiled in some alkaline liquid for removing the oil from it, and rendering it more elastic. The longest threads are to be employed for warp, the shorter for weft; and are to be woven in a hair-cloth loom. This fabric is to be passed between rollers, after which it is fit to be cut out into forms for making hats and bonnets, to be sewed together at the joints, and stiffened with a preparation of resinous varnishes, to prevent its being acted upon by perspiration or rain. A very considerable improvement in the lightness and elasticity of silk hats has been the result of this invention.

The foundation of men’s hats, upon whose outside the beaver, down, or other fine fur is laid to produce a nap, is, as I have described, usually made of wool felted together by hand, and formed first into conical caps, which are afterwards stretched and moulded upon blocks to the desired shape. Mr. Borradaile, of Bucklersbury, obtained a patent in November 1825, for a machine, invented by a foreigner, for setting up hat bodies, which seems to be ingeniously contrived; but I shall decline describing it, as it has probably not been suffered by the _Union_ to come into practical operation, and as I shall presently give the details of another later invention for the same purpose.

Silk hats, for several years after they were manufactured, were liable to two objections; first, the body or shell over which the silk covering is laid, was, from its hardness, apt to hurt the head; second, the edge of the crown being much exposed to blows, the silk nap soon got abraded, so as to lay bare the cotton foundation, which is not capable of taking so fine a black die as the silk; whence the hat assumed a shabby appearance. Messrs. Mayhew and White, of London, hat-manufacturers, proposed in their patent of February, 1826, to remedy these defects, by making the hat body of stuff or wool, and relieving the stiffness of the inner part round the brim, by attaching a coating of beaver upon the under side of the brim, so as to render the hat pliable. Round the edge of the tip or crown, a quantity of what is called stop wool is to be attached by the ordinary operation of bowing, which will render the edge soft and elastic. The hat is to be afterwards dyed of a good black colour, both outside and inside; and being then properly stiffened and blocked, is ready for the covering of silk.

The plush employed for covering silk hats, is a raised nap or pile woven usually upon a cotton foundation; and the cotton, being incapable of receiving the same brilliant black dye as the silk, renders the hat apt to turn brown whenever the silk nap is partially worn off. The patentees proposed to counteract this evil, by making the foundation of the plush entirely of silk. To these two improvements, now pretty generally introduced, the present excellence of the silk hats, may be, in a good measure, ascribed.

The apparatus above alluded to, for making the foundations of hats by the aid of mechanism, was rendered the subject of a patent, by Mr. Williams, in September, 1826; but I fear it has never obtained a footing, nor even a fair trial in our manufactures, on account of the hostility of the operatives to all labour-saving machines.

_Fig._ 538. is a side view of the carding engine, with a horizontal or plan view of the lower part of the carding machine, shewing the operative parts of the winding apparatus, as connected to the carding engine. The doffer cylinder is covered with fillets of wire cards, such as are usually employed in carding engines, and these fillets are divided into two, three, or more spaces extending round the periphery of the cylinder, the object of which division is to separate the sliver into two, three, or more breadths, which are to be conducted to, and wound upon distinct blocks, for making so many separate hats or caps.

The principal cylinder of the carding engine, is made to revolve by a rigger upon its axle, actuated by a band from any first mover as usual, and the subordinate rollers or cylinders belonging to the carding engine, are all turned by pullies, and bands, and geer, as in the ordinary construction.

The wool or other material is supplied to the feeding cloth, and carried through the engine to the doffer cylinder, as in other carding engines; the doffer comb is actuated by a revolving crank in the common way, and by means of it the slivers are taken from the doffer cylinder, and thence received on to the surfaces of the blocks _e e_. These blocks, of which two only are shewn to prevent confusion, are mounted upon axles, supported by suitable bearings in a carriage _f f_, and are made to revolve by means of a band _g g_, leading from a pulley on the axle of a conical drum beneath. The band _g_ passes over a pulley _h_, affixed to the axle of one of the blocks, while another pulley _i_, upon the same axle, gives motion, by means of a band, to as many other blocks as are adapted to the machine.

As it is necessary in winding the slivers on to the blocks, to cross them in different directions, and also to pass the sliver over the hemispherical ends of the blocks, in order that the wool or other material may be uniformly spread over the surface in forming the cap or hood for the shell or foundation of the intended hat, the carriage _f_, with the blocks, is made to traverse to and fro in lateral directions upon rollers at each end.

This alternating motion of the carriage is caused by a horizontal lever _l l_, (seen in the horizontal view _fig._ 538.) moving upon a fulcrum pin at _m_, which lever is attached to the carriage at one extremity _n_, and at the other end has a weighted cord which draws the side of this lever against a cam wheel _o_. This cam is made to revolve by means of a band and pulley, which turns the shaft and endless screw _q_, and this endless screw taking into a toothed wheel _r_, on the axle of the cam _o_, causes the cam to revolve, the periphery of which cam running against a friction roller on the side of the lever _l_, causes the lever to vibrate, and the carriage _f f_, attached to it, to traverse to and fro upon the supporting rollers, as described. By these means the slivers are laid in oblique directions, (varying as the carriage traverses,) over the surface of the blocks.

The blocks being conically formed, or of other irregular figures, it is necessary, in order to wind the slivers with uniform tension, to vary their speed according to the diameter of that part of the block which is receiving the sliver. This is effected by giving different velocities to the pulley on the axle of the conical drum _s_, corresponding with _e_. There is a similar conical drum _t_, placed in a reverse position in the lower part of the frame, which is actuated by a band from any convenient part of the machine passing over a pulley _u_, upon the axle of _t_. From the drum _t_, to the drum _s_, there is a band _v_, which is made to slide along the drums by the guidance of two rollers at the end of the lever _l_.

It will now be seen that when the larger diameter of the cam wheel _o_ forces the lever outwards, the band _v_ will be guided on to the smaller part of the conical drum _t_, and the larger part of _s_, consequently the drum _s_ will at this time receive its slowest motion, and the band _g_ will turn the blocks slower also; the reverse end of the lever _l_, having by the same movement, slidden the carriage into that position which causes the slivers to wind upon the larger diameter of the blocks.

When the smaller diameter of the cam is acting against the side of the lever, the weighted cord draws the end of the lever to the opposite side, and the band _v_ will be guided on to the larger part of the cord _t_, and the smaller part of the cone _s_; consequently, the quicker movement of the band _g_ will now cause the blocks _e e_ to revolve with a corresponding speed. The carriage _f_ will also be moved upon its rollers, to the reverse side, and the sliver of wool or other material be now wound upon the smaller parts and ends of the blocks, at which time the quicker rotation of the blocks is required. It may be here observed, that the cam wheel _o_ should be differently formed according to the different shaped blocks employed, so as to produce the requisite movements of the lever and carriage suited thereto.

It only remains to state, that there are two heavy conical rollers _w w_, bearing upon the peripheries of the blocks _e e_, which turn loosely upon their axles by the friction of contact, for the purpose of pressing the slivers of wool or other material on the blocks as it comes from the doffer cylinder of the carding engine, and when the blocks have been coated with a sufficient quantity of the sliver, the smaller end of the pressing rollers is to be raised, while the cap is withdrawn from the block. The process being continued as before, the formations of other bodies or caps is effected in the manner above described.

After the caps or bodies of hats, &c. are formed in the above described machine, they are folded in wet cloths, and placed upon heated plates, where they are rolled under pressure, for the purpose of being hardened. _Fig._ 539. represents the front of three furnaces _a a a_, the tops of which are covered with iron plates _b b b_. Upon these plates, which are heated by the furnace below, or by steam, the bodies wrapped in the wet cloths _c c c_, are placed, and pressed upon by the flaps or covers _d d d_, sliding upon guide rods, to which flaps a traversing motion is given, by means of chains attached to an alternating bar _e e_. This bar is moved by a rotatory crank _f_, which has its motion by pulleys from any actuating power. When any one of the flaps is turned up to remove the bodies from beneath, the chains hang loosely, and the flap remains stationary.

These caps or hat bodies, after having been hardened in the manner above described, may be felted in the usual way by hand, or they are felted in a fulling mill, by the usual process employed for milling cloths, except that the hat bodies are occasionally taken out of the fulling mill, and passed between rollers, for the purpose of rendering the felt more perfect.

Mr. Carey, of Basford, obtained a patent in October, 1834, for an invention of certain machinery to be employed in the manufacture of hats, which is ingenious and seems to be worthy of notice in this place. It consists in the adaptation of a system of rollers, forming a machine, by means of which the operation of roughing or plaiting of hats may be performed; that is, the beaver or other fur may be made to attach itself, and work into the felt or hat body, without the necessity of the ordinary manual operations.

The accompanying drawings represent the machine in several views, for the purpose of showing the construction of all its parts. _Fig._ 540. is a front elevation of the machine; _fig._ 541. is a side elevation of the same; _fig._ 542. is a longitudinal section of the machine; and _fig._ 543. is a transverse section; the similar letters indicating the same parts in all the figures.

Upon a brick or other suitable base, a furnace or fire-place _a_, is made, having a descending flue _b_, for the purpose of carrying away the smoke. A pan or shallow vessel _c c_, formed of lead, is placed over the furnace; which vessel is intended to contain a sour liquor, as a solution of vitriolic acid and water. On the edge of this pan is erected a wooden casing _d d d_, which encloses three sides, leaving the fourth open for the purpose of obtaining access to the working apparatus within. A series of what may be termed lantern rollers, _e e e_, is mounted on axles turning in the side casings; and another series of similar lantern rollers, _f f f_, is in like manner mounted above. These lantern rollers are made to revolve by means of bevel pinions, fixed on the ends of their axles, which are turned by similar bevel wheels on the lateral shafts _g_ and _h_, driven by a winch _i_, and geer, as shown in _figs._ 540. and 541.

Having prepared the bodies of the hats, and laid upon their surfaces the usual coatings of beaver, or other fur, when so prepared they are to be placed between hair cloths, and these hair cloths folded within a canvass or other suitable wrapper. Three or more hats being thus enclosed in each wrapper, the packages are severally put into bags or pockets in an endless band of sackcloth, or other suitable material; which endless band is extended over the lantern rollers in the machine.

In the first instance, for the purpose of merely attaching the furs to the felts (which is called slicking, when performed by hand), Mr. Carey prefers to pass the endless band _k k k_, with the covered hat bodies, over the upper series _f f f_, of the lantern rollers, in order to avoid the inconvenience of disturbing the fur, which might occur from subjecting them to immersion in the solution contained in the pan, before the fur had become attached to the bodies.

After this operation of slicking has been effected, he distends the endless band _k k k_, over the lower series of lantern rollers _e e e_, and round a carrier roller _l_, as shown in _fig._ 542.; and having withdrawn the hat bodies for the purpose of examining them, and changing their folds, he packs them again in a similar way in flannel, or other suitable cloths, and introduces them into the pockets or bags of the endless bands, as before.

On putting the machinery in rotatory motion in the way described, the hats will be carried along through the apparatus, and subjected to the scalding solution in the pan, as also to the pressure, and to a tortuous action between the ribs of the lantern rollers, as they revolve, which will cause the ends of the fur to work into the felted bodies of the hats, and by that means permanently to attach the nap to the body; an operation which when performed by hand, is called rolling off.

The improved stiffening for hat bodies proposed by Mr. Blades, under his patent of January, 1828, consists in making his solution of shellac in an alkaline lye, instead of spirits of wine, or pyroxylic spirit, vulgarly called naphtha.

He prepares his water-proof stiffening by mixing 18 pounds of shellac with 1-1/2 pounds of salt of tartar (carbonate of potash), and 5-1/2 gallons of water. These materials are to be put into a kettle, and made to boil gradually until the lac is dissolved; when the liquor will become as clear as water, without any scum upon the top, and if left to cool, will have a thin crust upon its surface of a whitish cast, mixed with the light impurities of the gum. When this skin is taken off, the hat body is to be dipped into the mixture in a cold state, so as to absorb as much as possible of it; or it may be applied with a brush or sponge. The hat body being thus stiffened, may stand till it become dry, or nearly so; and after it has been brushed, it must be immersed in very dilute sulphuric or acetic acid, in order to neutralize the potash, and cause the shellac to set. If the hats are not to be napped immediately, they may be thrown into a cistern of pure water, and taken out as wanted.

Should the hat bodies have been worked at first with sulphuric acid (as usual), they must be soaked in hot water to extract the acid, and dried before the stiffening is applied; care being taken that no water falls upon the stiffened body, before it has been immersed in the acid.

This ingenious chemical process has not been, to the best of my knowledge, introduced into the hat manufacture. A varnish made by dissolving shellac, mastic, sandarach, and other resins in alcohol, or the naphtha of wood vinegar, is generally employed as the stiffening and water-proof ingredient of hat bodies. A solution of caoutchouc is often applied to whalebone and horse-hair hat bodies.

The following recipe has been prescribed as a good composition for stiffening hats: four parts of shellac, one part of mastic, one half of a part of turpentine, dissolved in five parts of alcohol, by agitation and subsequent repose, without the aid of heat. This stiffening varnish should be applied quickly to the body or foundation with a soft oblong brush, in a dry and rather warm workshop; the hat being previously fitted with its inside turned outwards upon a block. The body must be immediately afterwards taken off, to prevent adhesion.

_Hat-Dyeing._--The ordinary bath for dyeing hats, employed by the London manufacturers, consists for 12 dozen, of--

144 pounds of logwood;
12 pounds of green sulphate of iron, or copperas;
7-1/2 pounds of verdigris.

The copper is usually made of a semi-cylindrical shape, and should be surrounded with an iron jacket or case, into which steam may be admitted, so as to raise the temperature of the interior bath to 190° F., but no higher, otherwise the heat is apt to affect the stiffening varnish, called the gum, with which the body of the hat has been imbued. The logwood having been introduced and digested for some time, the copperas and verdigris are added in successive quantities, and in the above proportions, along with every successive two or three dozens of hats, suspended upon the dipping machine. Each set of hats, after being exposed to the bath with occasional airings during 40 minutes, is taken off the pegs, and laid out upon the ground to be more completely blackened by the peroxidizement of the iron with the atmospheric oxygen. In 3 or 4 hours the dyeing is completed. When fully dyed, the hats are well washed in running water.

Mr. Buffum states that there are four principal objects accomplished by his patent invention for dyeing hats.

1. in the operation;

2. the production of a better colour;

3. the prevention of any of the damages to which hats are liable in the dyeing;

4. the accomplishment of the dyeing process in a much shorter time than by the usual methods, and consequently lessening the injurious effects of the dye-bath upon the texture of the hat.

_Fig._ 544. shows one method of constructing the apparatus. _a a_ is a semi-cylindrical shaped copper vessel, with flat ends, in which the dyeing process is carried on. _b b b_ is a wheel with several circular rims mounted upon arms, which revolve upon an axle _c_. In the face of these rims a number of pegs or blocks are set at nearly equal distances apart, upon each of which pegs or blocks it is intended to place a hat, and as the wheel revolves, to pass it into and out of the dyeing liquor in the vat or copper. This wheel may be kept revolving with a very slow motion, either by geer connecting its axle, _c_, with any moving power, or it may be turned round by hand, at intervals of ten minutes; whereby the hats hung upon the pegs, will be alternately immersed for the space of ten minutes in the dyeing liquor, and then for the same space exposed to the atmospheric air. In this way, the process of dyeing, it is supposed, may be greatly facilitated, and improved, as the occasional transition from the dye vat into the air, and from the air again into the bath, will enable the oxygen of the atmosphere to strike the dye more perfectly and expeditiously into the materials of which the hat is composed, than by a continued immersion in the bath for a much longer time.

A variation in the mode of performing this process is suggested, and the apparatus _fig._ 545. is proposed to be employed, _a a_ is a square vat or vessel containing the dyeing liquor; _b b_ is a frame or rack having a number of pegs placed in it for hanging the hats upon, which are about to be dyed, in a manner similar to the wheel above described. This frame or rack is suspended by cords from a crane, and may in that way be lowered down with the hats into the vat, or drawn up and exposed in the air; changes which may be made every 10 or 20 minutes.

I have seen apparatus of this kind doing good work in the hat-dyeing manufactories of London, that being a department of the business with which the Union has not thought it worth their while to interfere.

Mr. William Hodge’s patent improvements in hat dyeing, partly founded upon an invention of Mr. Bowler, consist, first in causing every alternate frame to which the suspenders or blocks are to be attached, to slide in and out of grooves, for the purpose of more easily removing the said suspenders when required. _Fig._ 546. represents the improved dyeing frame, consisting of two circular rims, _a a_, which are connected together at top and bottom, by three fixed perpendicular bars or the frame-work _b b b_. Two other perpendicular frames _c c_, similar to the former, slide in grooves, _d d d d_, fixed to the upper and lower rims. These grooves have anti-friction rollers in them, for the purpose of making the frames _c c_, to slide in and out more freely. The suspenders or substitutes for blocks, by these means, may be more easily got at by drawing out the frames _c c_, about half way, when the suspenders, which are attached to the frames with the hats upon them, may be easily reached, and either removed or altered in position; and when it is done on one side, the sliding frame may be brought out on the other, and the remaining quantity of “suspenders” undergo the same operation.

The patentee remarks, that it is well known to all hat dyers, that after the hats have been in the dyeing liquor some time, they ought to be taken out and exposed to the action of the atmospheric air, when they are again immersed in the copper, that part of the hat which was uppermost in the first immersion, being placed downwards in the second. This is done for the purpose of obtaining an uniform and regular dye. The patentee’s mode of carrying this operation into effect, is shown in the figure: _e e_ are pivots for the dyeing-frame to turn upon, which is supported by the arms _f_, from a crane above. The whole apparatus may be raised up or lowered into the copper by means of the crane or other mechanism. When the dyeing-frame is raised out of the copper, the whole of the suspenders or blocks are reversed, by turning the apparatus over upon the pivots _e e_, and thus the whole surfaces of the hats are equally acted upon by the dyeing material.

It should be observed, that when the dyeing-frame is raised up out of the copper, it should be tilted on one side, so as to make all the liquor run out of the hats, as also to cause the rims of the hats to hang down, and not stick to the body of the hat, or leave a bad place or uneven dye upon it. The second improvement described by the patentee, is the construction of “suspenders,” to be substituted instead of the ordinary blocks.

These “suspenders” are composed of thin plates of copper, bent into the required form, that is, nearly resembling that of a hat block, and made in such a manner as to be capable of contraction and expansion to suit different sized hats, and keep them distended, which may be altered by the workman at pleasure, when it is required to place the hats upon them, or remove them therefrom. The dyeing-frame at _fig._ 546. is shown with only two of these “suspenders,” in order to prevent confusion. One of these suspenders is represented detached at _fig._ 547., which exhibits a side view; and _fig._ 548. a front view of the same. It will be seen by reference to the figure, that the suspenders consist of two distinct parts, which may be enlarged or collapsed by a variety of means, and which means may be suggested by any competent mechanic. The two parts of the suspenders are proposed to be connected together by arms _g g_, and at the junction of these arms a key is connected for turning them round when required. It will be seen on reference to the front view, _fig._ 548., that the “suspenders” or substitutes for blocks, are open at the top or crown part of the hat; this is for the purpose of allowing the dyeing liquor to penetrate.

From the mixture of copperas and verdigris employed in the hat-dye, a vast quantity of an ochreous muddy precipitate results, amounting to no less than 25 per cent. of the weight of the copperas. This iron mud forms a deposit upon the hats, which not only corrodes the fine filaments of the beaver, but causes both them and the felt stuff to turn speedily of a rusty brown. There is no process in the whole circle of our manufactures, so barbarous as that of dyeing stuff hats. No ray of chemical science seems hitherto to have penetrated the dark recesses of their dye shops. Some hatters have tried to remove this corrosive brown ochre by a bath of dilute sulphuric acid, and then counteract the evil effect of the acid upon the black dye by an alkaline bath; but with a most unhappy effect. Hats so treated are most deceptious and unprofitable; as they turn of a dirty brown hue, when exposed for a few weeks to sunshine and air.

HEALDS, is the harness for guiding the warp threads in a loom; that is, for lifting a certain number of them alternately to open the shed, and afford passage to the decussating weft threads of the shuttle. See WEAVING.

HEARTH; (_Foyer_, Fr.; _Heerde_, Germ.) is the flat or hollow space in a smelting furnace upon which the ore and fluxes are subjected to the influence of flame. See COPPER, IRON, METALLURGY, &c.

HEAT, is that power or essence called caloric, the discussion of whose habitudes with the different kinds of matter belongs to the science of chemistry.

HEAT-REGULATOR. The name given by M. Bonnemain to an ingenious apparatus for regulating the temperature of his incubating stove rooms. See INCUBATION, ARTIFICIAL, for the manner of applying the Heat-Regulator.

The construction of the regulator is founded upon the unequal dilatation of different metals by the same degree of heat. A rod of iron _x_, _fig._ 549., is tapped at its lower end into a brass nut _y_, enclosed in a leaden box or tube, terminated above by a brass collet _z_. This tube is plunged into the water of the boiler, alongside of the smoke-pipe. (_Fig._ 549*. is a bird’s-eye view of the dial, &c.) The expansion of the lead being more than the iron for a like degree of temperature, and the rod enclosed within the tube being less easily warmed, whenever the heat rises to the desired pitch, the elongation of the tube puts the collet _z_ in contact with the heel _a_, of the bent lever _a_, _b_, _d_; thence the slightest increase of heat lengthens the tube anew, and the collet lifting the heel of the lever, depresses its other end _d_ through a much greater space, on account of the relative lengths of its legs. This movement operates near the axis of a balance-bar _e_, sinks one end of this, and thereby increases the extent of the movement which is transmitted directly to the iron skewer _v_. This pushing down a swing register diminishes or cuts off the access of air to the fire-place. The combustion is thereby obstructed, and the temperature falling by degrees, the tube shrinks and disengages the heel of the lever. The counterpoise _g_, fixed to the balance-beam _e_, raises the other extremity of this beam, by raising the end _d_ of the lever as much as is necessary to make the heel bear upon the collet of the tube. The swing register acted upon by this means, presents a greater section to the passage of the air; whence the combustion is increased. To counterbalance the effect of atmospheric changes, the iron stem which supports the regulator is terminated by a dial disc, round the shaft of the needle above _h_, _fig._ 549*.; on turning this needle, the stem below it turns, as well as a screw at its under end, which raises or lowers the leaden tube. In the first case, the heel falls, and opens the swing register, whence a higher temperature is required to shut it, by the expansion of the tube. We may thus obtain a regularly higher temperature. If, on the contrary, we raise the tube by turning the needle in the other direction, the register presents a smaller opening, and shuts at a lower temperature; in this case, we obtain a regularly lower temperature. It is therefore easy, says M. Bonnemain, to determine _à priori_ the degree of temperature to be given to the water circulating in the stove pipes. In order to facilitate the regulation of the apparatus, he graduated the disc dial, and inscribed upon its top and bottom, the words, Strong and Weak heat. See THERMOSTAT, for another HEAT-REGULATOR.

HEAVY SPAR, _sulphate of Baryta, or Cawk_; (_Spath pesant_, Fr.; _Schwerspath_, Germ.) is an abundant mineral, which accompanies veins of lead, silver, mercury, &c. but is often found, also, in large masses. Its colour is usually white, or flesh-coloured. It occurs in many crystalline forms, of which the cleavage is a right rhomboidal prism. It is met with also of a fibrous, radiated, and granular structure. Its spec. grav. varies from 4·1 to 4·6. It has a strong lustre, between the fatty and the vitreous. It melts at 35° Wedgew. into a white opaque enamel. Its constituents are 65·63 baryta, and 34·37 sulphuric acid. It is decomposed by calcination in contact with charcoal at a white heat, into sulphuret of baryta; from which all the baryta salts may be readily formed. Its chief employment in commerce is for adulterating white lead; a purpose which it readily serves on account of its density. Its presence here is easily detected by dilute nitric acid, which dissolves the carbonate of lead, and leaves the heavy spar. It is also a useful ingredient in some kinds of pottery, and glass.

HECKLE; (_Seran_, Fr.; _Hechel_, Germ.) is an implement for dissevering the filaments of flax, and laying them in parallel stricks or tresses. See FLAX.

HELIOTROPE; is a variety of jasper, mixed with chlorite, green earth, and diallage; occasionally marked with blood-red points; whence its vulgar name of _bloodstone_.

HEMATINE; is the name given by its discoverer Chevreul to a crystalline substance, of a pale pink colour, and brilliant lustre when viewed in a lens, which he extracted from logwood, the _hæmatoxylon Campechianum_ of botanists. It is, in fact, the characteristic principle of this dye-wood. To procure hematine, digest during a few hours ground logwood in water heated to a temperature of about 130° F.; filter the liquor, evaporate it to dryness by a steam bath, and put the extract in alcohol of 0·835 for a day. Then filter anew, and after having inspissated the alcoholic solution by evaporation, pour into it a little water, evaporate gently again, and then leave it to itself in a cool place. In this way a considerable quantity of crystals of hematine will be obtained, which may be readily purified by washing with alcohol and drying.

When subjected to dry distillation in a retort, hematine affords all the usual products of vegetable bodies, along with a little ammonia; which proves the presence of azote. Boiling water dissolves it abundantly, and assumes an orange-red colour, which passes into yellow by cooling, but becomes red again with heat. Sulphurous acid destroys the colour of solution of hematine. Potash and ammonia convert into a dark purple-red tint, the pale solution of hematine; when these alkalis are added in large quantity, they make the colour, violet blue, then brown-red, and lastly brown-yellow. By this time, the hematine has become decomposed, and cannot be restored to its pristine state by neutralizing the alkalis with acids.

The waters of baryta, strontia, and lime exercise an analogous power of decomposition; but they eventually precipitate the changed colouring matter.

A red solution of hematine subjected to a current of sulphuretted hydrogen becomes yellow; but it resumes its original hue when the sulphuretted hydrogen is removed by a little potash.

The protoxide of lead, the protoxide of tin, the hydrate of peroxide of iron, the hydrate of oxides of copper and nickel, oxide of bismuth, combine with hematine, and colour it blue with more or less of a violet cast.

Hematine precipitates glue from its solution in reddish flocks. This substance has not hitherto been employed in its pure state; but as it constitutes the active principle of logwood, it enters as an ingredient into all the colours made with that dye stuff.

These colours are principally violet and black. Chevreul has proposed hematine as an excellent test of acidity.

HEMATITE; (_Fer Oligiste_, Fr.; _Rotheisenstein_, Germ.) is a native reddish-brown peroxide of iron, consisting of oxygen 30·66; iron 60·34. It is the kidney ore of Cumberland, which is smelted at Ulverstone with charcoal, into excellent steel iron.

HEMP; (_Chanvre_, Fr.; _Hanf_, Germ.) is the fibrous rind of the bark of the _cannabis sativa_, which is spun into strands or yarn for making ropes, sail-cloth, &c. It is prepared for spinning in the same way as flax, which see. _Hemp-seed_ contains an oil which is employed for making soft soap, for painting, and for burning in lamps. See OILS.

Importation of undressed hemp for home consumption; and amount of duty, in

1837. 1838. | 1837. 1838.
Cwts. 596,994·3 | 667,017 | _£_2487 | _£_2780

HEPAR; which signifies liver in Latin, was a name given by the older chemists to some of those compounds of sulphur with the metals which had a liver-brown colour. Thus the sulphuret of potassium was called liver of sulphur.

HEPATIC AIR; sulphuretted hydrogen gas.

HERMETICAL SEAL, is an expression derived from Hermes, the fabulous parent of Egyptian chemistry, to designate the perfect stoppage of a hollow vessel, by the cementing or melting of the lips of its orifice; as in the case of a glass thermometer, or matrass.

HIDE; (_Peau_, Fr.; _Haut_, Germ.) the strong skin of an ox, horse, or other large animal. See LEATHER.

Importation of untanned hides for home consumption; and amount of duty, in

1837. 1838. | 1837. 1838.
332,877 | 301,890 | _£_46,190 | _£_36,647

HIRCINE; from _hircus_, a ram; is the name given by Chevreul to a liquid fatty substance, which is mixed with the oleine of mutton suet, and gives it its peculiar rank smell. Hircine is much more soluble in alcohol than oleine. It produces _hircic_ acid by saponification.

HOG’s LARD; see FATS.

HONEY; (_Mel_, Fr.; _Honig_, Germ.) is a sweet viscid liquor, elaborated by bees from the sweet juices of the nectaries of flowers, and deposited by them in the waxen cells of their combs. Virgin honey is that which spontaneously flows with a very gentle heat from the comb, and common honey is that which is procured by the joint agency of pressure and heat. The former is whitish or pale yellow, of a granular texture, a fragrant smell, and a sweet slightly pungent taste; the latter is darker coloured, thicker, and not so agreeable either in taste or smell. Honey would seem to be merely collected by the bees, for it consists of merely the vegetable products; such as the sugars of grape, gum, and manna; along with mucilage, extractive matter, a little wax, and acid.

HONEY-STONE; (_Mellite_, Fr.; _Honigstein_, Germ.) is a mineral of a yellowish or reddish colour, and a resinous aspect, crystallizing in octahedrons with a square base; specific gravity 1·58. It is harder than gypsum, but not so hard as calc-spar; it is deeply scratched by a steel point; very brittle; affords water by calcination; blackens, then burns at the flame of the blowpipe, and leaves a white residuum which becomes blue, when it is calcined after having been moistened with a drop of nitrate of cobalt. It is a mellate of alumina, and consists of:

Klaproth. Wöhler.

Mellitic acid 46 44·4
Alumina 16 14·5
Water 38 41·1
--- -----
100 100·0

The honey-stone, like amber, belongs to the geological formation of lignites. It has been hitherto found clearly in only one locality, at Artern in Thuringia.

HOP; (_Houblon_, Fr.; _Hopfen_, Germ.) is the name of a well-known plant of the natural family of Urticeæ, and of the dioecia pentandria of Linnæus. The female flowers, placed upon different plants from the male, grow in ovoid cones formed of oval leafy scales, concave, imbricated, containing each at the base an ovary furnished with two tubular open styles, and sharp pointed stigmata. The fruit of the hop is a small rounded seed, slightly compressed, brownish coloured, enveloped in a scaly calyx, thin but solid, which contains, spread at its base, a granular yellow substance, appearing to the eye like a fine dust, but in the microscope seen to be round, yellow, transparent grains; deeper coloured, the older the fruit. This secretion, which constitutes the useful portion of the hop, has been examined in succession by Ives, Planche, Payen, and Chevallier. I have given a pretty full account of the results of their researches in treating of the hop, under the article BEER.

HORDEINE, is the name given by Proust to the peculiar starchy matter of barley. It seems to be a mixture of the starch, lignine, and husks, which constitutes barley meal. See BEER.

HORN; (Eng. and Germ.; _Corne_, Fr.) particularly of oxen, cows, goats, and sheep, is a substance soft, tough semi-transparent, and susceptible of being cut and pressed into a variety of forms; it is this property that distinguishes it from bone. Turtle or tortoise shell seems to be of a nature similar to horn, but instead of being of a uniform colour, it is variegated with spots.

These valuable properties render horn susceptible of being employed in a variety of works fit for the turner, snuff-box, and comb maker. The means of softening the horn need not be described, as it is well known to be by heat; but those of cutting, polishing, and soldering it, so as to make plates of large dimensions, suitable to form a variety of articles, may be detailed. The kind of horn to be preferred is that of goats and sheep, from its being whiter and more transparent than the horn of any other animals. When horn is wanted in sheets or plates, it must be steeped in water, in order to separate the pith from the kernel, for about fifteen days in summer, and a month in winter; and after it is soaked, it must be taken out by one end, well shaken and rubbed in order to get off the pith; after which it must be put for half an hour into boiling water, then taken out, and the surface sawed even lengthways; it must again be put into the boiling water to soften it, so as to render it capable of separating; then, with the help of a small iron chisel, it can be divided into sheets or leaves. The thick pieces will form three leaves, those which are thin will form only two, whilst young horn, which is only one quarter of an inch thick, will form only one. These plates or leaves must again be put into boiling water, and when they are sufficiently soft, they must be scraped with a sharp cutting instrument, to render those parts that are thick even and uniform; they must be put once more into the boiling water, and finally carried to the press.

At the bottom of the press employed, there must be a strong block, in which is formed a cavity, of nine inches square, and of a proportionate depth; the sheets of horn are to be laid within this cavity, in the following manner: at the bottom, first a sheet of hot iron, upon this a sheet of horn, next again a sheet of hot iron, and so on, taking care to place at the top a plate of iron even with the last. The press must then be screwed down tight.

There is a more expeditious process, at least in part, for reducing the horn into sheets, when it is wanted very even. After having sawed it with a very fine and sharp saw, the pieces must be put into a copper made on purpose, and there boiled, until sufficiently soft, so as to be able to be split with pincers; the sheets of horn must then be put in the press, where they are to be placed in a strong vice, the chaps of which are of iron and larger than the sheets of horn, and the vice must be screwed as quick and tight as possible; let them cool in the press or vice, or it is as well to plunge the whole into cold water. The last mode is preferable, because the horn does not shrink in cooling. Now draw out the leaves of horn, and introduce other horn to undergo the same process. The horn so enlarged in pressing, is to be submitted to the action of the saw, which ought to be set in an iron frame, if the horn is wanted to be cut with advantage, in sheets of any desired thickness, which cannot be done without adopting this mode. The thin sheets thus produced must be kept constantly very warm between plates of hot iron to preserve their softness; every leaf being loaded with a weight heavy enough to prevent its warping. To join the edges of these pieces of horn together, it is necessary to provide strong iron moulds suited to the shape of the article wanted, and to place the pieces in contact with copper-plates or with polished metal surfaces against them; when this is done, the whole is to be put into a vice and screwed up tight, then plunged into boiling water, and after some time it is to be removed from thence and immersed in cold water. The edges of the horn will be thus made to cement together and become perfectly united.

To complete the polish of the horn, the surface must be rubbed with the subnitrate of bismuth by the palm of the hand. The process is short, and has this advantage, that it makes the horn dry promptly.

When it is wished to spot the horn in imitation of tortoise-shell, metallic solutions must be employed as follows:--To spot it red, a solution of gold in aqua regia must be employed; to spot it black, a solution of silver in nitric acid must be used; and for brown, a hot solution of mercury in nitric acid. The right side of the horn must be impregnated with these solutions, and they will assume the colours intended. The brown spots can be produced on the horn by means of a paste made of red lead, with a solution of potash, which must be put in patches on the horn, and subjected some time to the action of heat. The deepness of the brown shades depends upon the quantity of potash used in the paste, and the length of time the mixture lies on the horn. A decoction of Brazil wood, or a solution of indigo, in sulphuric acid, or a decoction of saffron, and Berbary wood may also be used. After having employed these materials, the horn may be left for half a day in a strong solution of vinegar and alum.

In France, Holland, and Austria, the comb-makers and horn-turners use the clippings of horn, which are of a whitish yellow, and tortoise-shell skins, out of which they make snuff-boxes, powder-horns, and many curious and handsome things. They first soften the horn and shell in boiling water, so as to be able to submit them to the press in iron moulds, and by means of heat form them into one mass. The degree of heat necessary to join the horn clippings must be stronger than that for shell skins, and it can only be found out by experience. The heat must not however be too great, for fear of scorching the horn or shell. Considerable care is required in these operations, not to touch the horn with the fingers, nor with any greasy body, because the grease will prevent the perfect joining. Wooden instruments should be used to move them, while they are at the fire, and for carrying them to the moulds.

In making a ring of horn for bell-pulls, &c., the required piece is to be first cut out in the flat of its proper dimensions, and nearly in the shape of a horse-shoe; it is then pressed in a pair of dies to give its surface the desired pattern; but previous to the pressure, both the piece of horn and the dies are to be heated; the piece of horn is to be introduced between the dies, squeezed in a vice, and when cold, the impression or pattern will be fixed upon the horn. One particular condition, however, is to be observed in the construction of the dies, for forming a ring. They are to be so made, that the open ends of the horse-shoe piece of horn, after being pressed, shall have at one end a nib, and at the other a recess of a dovetailed form, corresponding to each other; and the second operation in forming this ring of horn is to heat it, and place it in another pair of dies, which shall bring its open ends together, and cause the dovetailed joints to be locked fast into each other, which completes the ring, and leaves no appearance of the junction.

In forming the handles of table knives and forks, or other things which require to be made of two pieces, each of the two pieces or sides of the handle is formed in a separate pair of dies; the one piece is made with a counter-sunk groove along each side, and the other piece with corresponding leaves or projecting edges. When these two pieces are formed, by first being cut out of the flat horn, then pressed in the dies in a heated state, for the purpose of giving the pattern, the two pieces are again heated and put together, the leaves or edges of the one piece dropping into the counter-sunk grooves of the other piece, and being introduced between another pair of heated dies, the joints are pressed together and the two pieces formed into one handle.

In making the knobs for drawers which have metal stems or pins to fasten them into the furniture, the face of the knob is to be first made in a die, as above described, and then the back part of the knob with a hole in it; a metal disc of plate-iron is next provided, in which the metal stem or screw pin is fixed, and the stem being passed through the aperture in the back piece, and the two, that is, the back and front pieces of horn put together, they are then heated and pressed in dies as above described; the edge of the back piece falling into the counter-sunk groove of the front piece, while by the heat they are perfectly cemented together.

HORNSILVER; (_Argent Corné_, or _Kerargyre_, Fr; _Hornsilber_, Germ.) is a white or brownish mineral, sectile like wax or horn; and crystallizing in the cubic system. Its specific gravity varies from 4·75 to 5·55. Insoluble in water; not volatile; fusible at the blowpipe, but difficult of reduction by it. It deposits metallic silver when rubbed with water upon a piece of clean copper or iron. It consists of 24·67 chlorine, and 75·32 silver.

Hornsilver is rare in the European mines, but it occurs in great quantity in the districts of Zacatecas, Fresnillo, and Catarce, in Mexico; and in Huantajaya, Yauricocha, &c., in Peru; where it is abundantly mixed with the ores of hydrate of iron, called Pacos and Colorados, interspersed with veins of metallic silver, which form considerable deposits in the _penæan_ limestones. There it is profitably mined as an ore of silver.

HORNSTONE; is a variety of rhomboidal quartz. Being both hard and tough, it is well adapted to form the stones of pottery mills for grinding flints; it is called chert in Derbyshire, where it abounds.