The American Miller and Millwright's Assistant, by William Carter Hughes
Having been requested by the publisher, Mr. Henry C. Baird, to enlarge and revise my book on Milling, I take pleasure in saying to my readers, that my first endeavors have been so well received by those engaged in the practical operation of milling - for whose benefit the work was designed - that this edition will be found more to the purpose of both the miller and mill owner. The improvements made in milling during the last four years have been numerous as regards machinery. In merchant mills the greatest benefit has resulted to our business, within the last four years, in this particular; and the first I shall notice is, the present arrangement of merchant bolts, where the No. 10 cloth is found to be more suitable throughout, both for return and dusters; as it is easily demonstrated, that where the flour is properly ground, if you have length of bolts sufficient for your grinding capacity, and all coarser as above stated, you will not require to regrind any portion of your offal a second time, making a great savings in the expense of manufacturing, and an improvement in the quality of the flour, as you bran will be much more inform than where a second grinding is resorted to. The next improvement of importance to millers is that of cleaning the grain perfectly. I have added to this edition a number of very excellent machines, (such as smut and winnowing machines,) all of which are necessary to give the flour a good color. The next machine I shall call your attention to, (that I consider no mill perfect without,) is Kinman's Flour Packer and Chest combined; an engraving of which is given. And last, though not least, indeed, is the improvement in the construction of wheat may be considered the key to the whole milling business, a good French burr millstone, and those made by Munson and Hart, of Utica, N. Y., in particular. This firm have lately added an improved eye to their millstones, that allows them to be run at any desired motion, without clogging. The milling business occupies a respectable portion of our national industry, and gives employment to a large investment of capital in all the principle wheat growing States of this Union, which contributes largely to the benefit of our American farmers, in making a home market for Wheat and Indian Corn, the two principle staples of American produce. The author of this work, having spent the best portion of his life in the pursuit of his calling as a practical Miller, begs to say, in preparing this work for the milling public, that his object is to establish a correct guide to a business which so little is known about, in a shape of substantial reference, instead of speculative theories, and that confined to the minds only of those who are attached to the business, either by employment of capital or otherwise. Special regard has also been paid to most of the essential improvements which have, of late, been introduced for the benefit of the miller. And we can also say, that we have omitted a large number of late inventions, from the belief of their utter worthlessness for a great many of the purposes for which they were designed; and those of our friends who furnished us with drafts and long statements of their peculiar views on milling, will please accept our thanks for the same, and this, our apology for not giving them a place in these pages. With a full assurance and hope that this work may prove useful to all engaged in milling. I respectfully subscribe myself, Wm. C. Hughes.
The following table shows the required length of over shot or breast wheels, on falls from 10 to 30 feet, to drive from one to four run of four and a half feet stones, with all the necesary machinery for a merchant flouring mill. The column marked "Fall" shows the number of feet fall on the breast wheel, or the diameter of the over shot. --------------------------------------------------------------------------------------------------------------------- Diameter of overshot in fall - Number of run of stones.1 2 3 4 Multiply the number of run required by the length as stated in the table. --------------------------------------------------------------------------------------------------------------------- First column-Diameter of water wheel Second column-width of water wheel with one pair of millstones. To determine the width of a water wheel to power; 2 pairs, 3 pairs or 4 pairs, multiplty the length (width) of wheel in feet to determine how much wider or larger in diameter a wheel should be (diameter in the case of a breast shot water wheel). length of wheel in feet x-twice-3 times-4 times. --------------------------------------------------------------------------------------------------------------------- 10' -7' 11' -6 1/4' 12' -5 3/4' 13' -5 1/2' 14' -5' 15' -4 1/2' 16' -4 1/4' 17' -4' 18' -4' 19' -3 3/4' 20' -3 1/2' 21' -3 1/4' 22' -3 1/4' 23' -3' 24' -3' 25' -2 3/4' 26' -2 2/3' 27' -2 1/2' 28' -2 1/2' 29' -2 1/2' 30' -2 1/4'
There is no description of within, within our knowledge, that affords so much variety of texture, or that is so well adapted for grinding, as that known as the "French Burr." It varies from the closest of quality to the openest and poorest of the stone species. We shall now, in this chapter give the necessary directions, which, if attended to strictly, will always insure the miller, who should always be the person to select the quality of millstone which will enable him to make the best yields, as well as a better quality of flour than he can otherwise do no any other description or selection of this kind of stone. In the first place, I here remark, that every well informed, practical miller, of at least ten years' experience in the business, must be well versed in the difference of the French burr, which, long practice, his experience tells him that which is likely to do the best work, when set in order for grinding; he must be acquainted, also with what is termed the best stock for making millstones, as the stone is imported from France in blocks of various sizes, which blocks of stone differ as much in color as they do in quality. The first thing, to be done, on going to the millstone manufactory, is to select those sized stones you want. By examination, you will soon be able to discover whether they suit these directions or not; if the stone is of a close appearance, and of a white color, without any yellowish spots in the seams, or where the blocks join each other closely fitted, and the said seems must be parallel with the diameter, as by being so they do not break off the edges of the seams, by interfering with the furrows; also, do not forget to take a mill pick, and go over every block, which you may do in a few minutes, and if they prove of an equal hardness, then we should recommend that run as being a good run of stones for grinding wheat expressly. If they should prove, after trying them in this manner, that some parts of the different blocks of which the stone is composed are rather softer, and incline to be open about the eye, do not take them, as it will take up more time in dressing them, to keep them in a good face, than two such as we have first described. The clear white and sometimes variegated stock, resembling marble, is the best description of French burr, for all uses; as that kind of stock is always free and hard, and holds an edge as long as any other color. For grinding corn expressly, stone of a different color may be used best for this kind of grinding; I say best because it is of a keener temper, and not so subject to soft, open places, as the stone first described. This kind of stock is of a pale, bluish cast, and more particularly known to millers for its resistance of right good steel; but after being dressed, will grind more hard corn than any other kind of stone in use. Of course if this quality, we have dressed a large number of run for different mills, expressly for flouring, which, with judicious management, answer a very good purpose; but I do not recommend this kind, as it requires a miller of good judgment to superintend in dressing them; for, in the first place, if they are allowed to get smooth, they are apt to heat, as well as grind wheat oily. In the next place, if they are dressed at all rough, they will make very specky flour, and grind harsh, - two evils not to be tolerated about a flouring mill, further, the nature of this kind of burr is of a dead, heavy texture, and entirely unfit for steam mills. Where the power is at all varying or unsteady, this kind of burr imparts to the flour a kind of grayish cast. There is also another description of burr stock which I must here notice, and the worst of all others to the miller who has been so unfortunate as to purchase such stones with the least reasonable hope that he has got good ones. This is a burr of a yellowish color, called by some the Fox burr, and not at all badly named, as it is very deceptive in its appearance. In dressing this kind of stone, it resembles a knotty nature, with a good inclination to curl as you strike it with the pick. After you have ground with it for the space of twenty four hours, take it up, and it has all the appearance of being varnished with the best opal varnish, which makes the miller sigh for "the good old days of Adam and Eve, " when the gray Laurel Hill rock Stone were fashion, or what the Virginia miller calls "Virginia Creeper," either of which is preferable to the last described French Burr. Having treated of the French Burr, we shall now direct out remarks to that of our American production, the Raccoon Burr.
This description of stone is of American production, and its geological nativity is confined to the State of Ohio, not being known elsewhere. Its locality is in Muskingram and adjoining counties, known by the name of the "Flint Ridge." This stone is a description of burr, and makes a very good substitute for the imported or French burr. During may residence in, the State of Ohio, I was employed by the Messrs, Adams, of Muskingum county, who do a large business in flouring, being the most extensive millers in that part of the State. One of their mills, in which the author was employed, was of six run of stones, all of them of Raccoon burr, and having dressed them, the only conclusions I drew, from the work the stones made, was, that they required to be dressed oftner than the generality of the French burr. The reputation of this mill than stood high in New York for making a good article of superfine flour. The difference in the price between the Raccoon and imported being from 35 to 45 per cent cheaper. They are put together in blocks and fitted up as the French burr, and will answer a good purpose for grist mills, or for grinding coarse grains, such as grist grinding generally consists of, for the use of the farmer.
While the mill is in progress of building, the stones may be prepared by the miller who is to have charge of the running of the mill when completed, as no other than the head miller should direct the operation of putting in the dress; and any fault in their operation he should be held individually accountable for. It being necessary to take the stone out of wind before the dress is laid out, it may be done in the following manner: First, prepare yourself with a good tram staff of the following shape; have your staff dressed four inches wide, with a hole through it exactly four inches wide, with a hole through it exactly in the center; then frame two posts, two by three inches wide, at equal distances from your center hole, and then place a cap on the posts in which your elevation screw is inserted, for the purpose of allowing the staff to come in contact with the stone. In addition to this, there is a plan different in its construction, which is to use a bar of flat iron, of any suitable size, say half an inch thick, by one inch wide, or one and a half inch wide; bend it in a circular form, and let it into the staff with screws; drill a hole through the center, exactly in range with the hole through the staff for the elevating screw. This description of staff is easier made than the first mentioned, and much more easily kept in repair. The spindle that the staff works on requires to be an inch in length; one of this size will work without springing. It will be necessary to have these screws, which are to be inserted into the staff, in three different sections of the hole which the spindle passes through. The object of these screws is simply to allow the staff to be trammed or centered to the face of the stone, by altering any three of those points which the screws represent. By placing your spindle properly in the eye of the stone, the screws may be dispensed with, and also a great deal of trouble in using the screw to train the staff, as every time the staff is taken off the spindle, in replacing it, the points require to be examined and trammed over. If the spindle is properly placed in the eye, no objection can be found in using the staff without screws, as the main center for taking the wind out of the stone is entirely dependent on the spindle which the staff is suspended on; then the miller must center his spindle from the circumference of the stone, instead of centering it by the eye, as many do, supposing that the eye is always in the center of the stone, which is not always the case. Being prepared now to use paint for the staff, which may be prepared by mixing 2 ounces of either Spanish brown or Venetian red; the latter is preferable, as it shows on the stone better with spirits of turpentine or soft water. By means of the screw at the top of the spindle, you allow the staff to come down so as to slightly touch the stone, by which your work off all the high places, until the stone is perfectly out of wind, and may be known to be so when it paints the face all over exactly alike. For new stone, the eye blocks should be worked about a sixteenth below the rest of the face. The next part of the work, being to lay out and draft a proper dress, may be done as follows: Before we dismiss the subject of taking millstones out of wind, we will just refer to another mode; namely, the using of three angles laid out on the surface of the stone, and each angle intersecting the other, which forms a center by working the lowest angle shown on the stone first to a good face, and working the others down to it. This is a mode we cannot recommend, as it consumes nearly as long again to prepare a stone with this plan as it does with the tram staff, consequently is much more expensive, and its principles belong to a past generation, but are mechanically correct, and answers in places where a tram staff cannot be got readily.
The first thing we shall notice under this head is the amount of draft necessary for your leading furrows. This must be varied according to the size and quality of your stone. Stones that are close require more than open ones, consequently the miller's own experience must direct him to define the difference between close and open millstones, knowing that open stones have greater amount of draft than close ones. But I have found, from my own experience, that there is, also another essential point to be considered, that is, the particular dress you use, as in no quality of stone, either close or open, should as much draft be given to a stone of any size where a circle dress is used, as may be given where the dress is straight. My rule is, for a straight dress, in close stone, an inch to the foot of the diameter, and three quarters of an inch with the curve. After you have made up your mind on the amount of draft which you intend to use, set a piece of board in the eye of your stone, which for convenience we will call a draft board; then if you wish to use four inches draft, set your dividers four inches, and after you have found the exact center of your stone, place the point of your dividers in that center, and strike a circle on the board, called the draft circle. This is the first preparatory step of importance, the next being to know what way your stone is to run, whether with the sun or contrary; if with the sun, use circle dresses in preference to all others, will require abundant proof on this subject, we hope to give it to them; and if we succeed in enlightening them on the main error of all circular dresser, all we ask of them is to adopt what science and practical experience prove to be the better mode. To illustrate this subject fully, we take a millstone of four and a half feet in diameter, with a motion of 175 to 180 revolutions per minute, and prepare it for flouring with a circular dress, with furrows on a circle of once and a half the diameter of the stone. I pitch on this particular dress to illustrate my views, as eight tenths of all the circular dresses I have examined are drafted at the eye of the lowest number of inches generally given, being three and a half inches at the center, I ask, what will the angle be, that the furrows will pass each other, from the eye to the periphery? We suppose, that in such a draft above described, the angle of the furrows are equal; this should not be the case, when we consider that the center force increases as the distance from the center increases, caused by the circumference of every superficial inch of the stone increasing. We ask, then, how are you to bring the same amount of meal on this increasing velocity of the skirts of the stone, that you have at the center, when your draft, in both parts of your stone, are alike demonstrated by purely scientific principles, being governed by the laws of circular motion, on the same principles as above described? We affirm, that at least one twentieth of the pressure used on a stone of four and a half feet diameter, making 175 revolutions per minute, grinding 15 bushels per hour might be dispensed with, or avoided, if the draft or dress was applied in such a manner as to decrease as the central force increased, which would allow the angle of draft with which their furrows cross each other, in inverse proportion to their diameter. If the twentieth of the pressure need not be used; that is just one twentieth of the power saved, with at least an equal advantage gained of five per cent, in the quality of the flour; as the less pressure used in manufacturing, the better the flour after it is manufactured. This most all will admit. With this dress, more time is consumed in keeping your stone in proper order, than should be, as all experienced millers will readily admit. The skirts of the stone with circular dresses are always lower than either the breast or eye; and the smaller the circle used, the greater this difficulty will exist, it being impossible to give the skirt as must of the meal, with this dress, as its relative proportions require. Where a stone four and a half feet in diameter is grinding, say 15 bushels per hour of wheat, and running night and day, in twenty four hours from the time it was started, the heat caused by the great pressure used becomes intense, as it forms a scalding temperature, which greatly affects the quality of the flour. To test this principle more full, I have compared the degrees of the temperature of the meal with this dress, and what is called the old fashioned straight quarter, as the meal issued from the stone, and found the following results:- The circle dress ground the warmest by ten to twenty degrees of Fahrenheit; both the same kind and sized stone grinding about the same quantity. On two separate examinations of the heat of the meal, the stone with the circle dress had 18 leading furrows, and the straight quarter 16 furrows. Now, by this experiment alone, I do not say that this quarter, or straight dress, is the one I should recommend all millers to use. No, by no means; as the disproportion in the draft of its short furrows condemns it alone. But the experiment went to prove its superiority over the circle, which was readily discovered in the lively, rich color of the flour, and the clean appearance of the offal. The different dresses, are all got up from those two, - the circle and straight quarter dress; and I must say, that their inventors were actuated more by a love of variety and novelty, than from the dictates of practical experience. For that reason, we shall not take time to notice them at further length than considering it no advantage to the miller, although there may be some who will value it more than any other dress (quarter dress) represented, because they have spent more time in getting up, than they have taken to examine the error they have made by introducing a combination of artificial drafts for millstones, contrary to those laws of circular motion and central forces which govern all kinds of millstone dresses, of whatever kind used. We shall not present that dress for millstones that science and experience show to be best for all sizes of stone and varieties of central motion occasioned by the revolutions made per minute of the stone. These dresses represent a perfectly straight furrow, one inch and one eight in width, for a stone four and a half feet in diameter. The number of leading furrows should be from 16 to 20, or 21, if the stone is more than ordinarily close; I prefer 21. Then divide those quarters with another furrow each, which will give 42 whole furrows, allowing the short furrows to enter the leading ones in close stones: This dresses may be called, properly, the "new quarter dress;" its superiority over the old 16 dress is apparent to all, when we examine the drafts. Millers who may think that there is too much face on the skirt, may safely increase the size of their furrows one eight of an inch on the skirt, and in very open stones may decrease it accordingly, as well as the number of furrows. I have the opinion of several of the best millers in the United States, all agreeing on this dress as being the best in use. By the use if it, we entirely dispense with that short furrow necessarily used in the old 16 quarter dress, by giving the short furrow in the new quarter dress about the same draft as the second furrow in the old, which serves to make the flour better, as less pressure is used with the new quarter dress than with the old. The short furrows in the 16 quarter dress, that angle at which they cross each other being too obtuse to admit of cutting, as many, the angle being 84 degrees of draft, they push the meal out, and cannot act otherwise. With the new quarter dress, as described, I should not recommend more draft at the eye of the stone than three and a half inches, where its motion is from 160 to 180 revolutions per minute, for a stone of four and a half feet in diameter, with the same proportion, according to the size of the stone.
The manner in which furrows are shaped in very important, as, in discharging the meal, they will, if not properly made, make too many middlings, and allow the bran to pass out thicker than it ought to be. the proper form, I have found, for them, is a perfectly true taper. From the first edge, commonly called the track edge, up to the second, called the feather edge, and of a depth of three eighths of an inch at the back or first edge, up to a sixteenth part of an inch at the feather edge of a new stone, and not deeper than the depth of a good heavy crack, when your stones are in perfectly good face for flouring. Now, much pains in the mechanical construction of them may be saved to the young miller by the use of a gauge and staff. To dress his furrows you want to make, cut on wood, which will assist you. To make all your furrows precisely the same depth, the staff is a small, flat rule, four or five inches long, by which you can apply paint to your furrows to work then even, by which much time is spared, for the paint shows you all the high places, so that not one stroke of the pick need be lost. For flouring, you furrows require to be as smooth as the face, as rough furrows make the flour specky. I have heard millers object frequently to their bolts not being right, when the whole cause lay in the rough manner in which their stones are dressed.
Every three months is as often as necessary to dress the furrows, but in a mill that does of good business, the face of the stones requires cracking as often as very four days, the stone running night and day. Cracking the face, as it is termed, is an artificial mode of cutting the face of a millstone in parallel lines with the furrows by which the bran is cleaned; consequently, when well done, a stone will grind a third faster than without the cracking face, and the flour is far superior. With stones cracked with about from 26 to 30 in every superficial inch of the face, reason tells us that they need not be pressed so close together. It requires a good deal of practice to be perfect in this part of the miller's art, but by the use of practice we become perfect in this, as well as any other branch of the business. After the stones are taken up for the purpose of sharpening them, the first thing the miller should do is to take a soft sandstone, which should be kept for the purpose, and rub the face of the millstones all over with it. The object of this is to scour the face, which leaves it in better order to receive the work you are going to put to it. Sweep them off clean, and then apply your staff. If your stone should be higher about the eye and breast, skin off those places, and crack the balance; then your stone is ready for grinding. If you should find your stones in good face when you take them up, with the paint equally distributed all over the face of the stone alike, being the highest about the eye, then the stones are considered to be in good face; then crack them all over nicely, without breaking the face, which must be done with a sharp pick; then apply a little tallow around your spindle neck, and if the spindle is loose, tighten it, and tram your spindle down, as they are in good order for grinding.
Much has been attempted to improve this important tool, but all I have seen are worthless, in comparison with that made from the cast steel bar, as generally used. The size of the steel bar ought to be one and one eighth of an inch square; cut in six inches long, and draw it with a ture taper from the center each way. The best cast steel should be used for mill picks; and when your picks are done, they should be an inch and a guarter to three eighths wide. At each end of the steel should be hardened till they show a straw color for two inches. The blacksmith who sharpens them requires to pay a good deal of attention, to prevent the steel from getting too hot, as it is easily detected when done; and also to hammer them on an anvil that is smooth, to prevent the edges from cracking. I have taken a good deal of pains to get a recipe for making a composition for tempering cast steel, which may be found useful.
It is generally very difficult for the miller to get the blacksmith to give the steel its proper temper, from a want of a sufficient knowledge on the part of blacksmiths generally what the temper should be. We here insert a composition for the purpose, which assists the process of tempering cast steel, by assisting the steel to retain its natural qualities and fineness of temper in opposition to the great degree of heat used for drawing and tempering, as the oftener steel is heated, the more brittle become its fibres, which renders it worthless to the mechanic, and more particularly to the miller. To 3 gallons of water add 3 ounces of spirits of nitre, 3 ounces of spirits of harthorn, 3 ounces of white vitriol, 3 ounces of salammoniac, 3 ounces of alum, 6 ounces of salt, with a double handful of hoof parings; the steel to be heated a dark cherry red. Every miller should keep a large jug of this preparation in the mill, for tempering his picks; also, it must be kept corked tight to prevent evaporation.
The proof staff is made of cast iron, with a perfectly true face, and set in a case with a cover to it. It is for the purpose of keeping the wood staff, that is used to work the stone, by, in order; as, by applying one one the other, you will soon detect any error in your stone staff. A little sweet oil should be applied on the proof when about to try the order which your stone is in. Rub the face of the iron staff gently with a woolen cloth, with a small quantity of oil; then apply the wooden one; the oil of the iron staff will adhere to the wood, so as to guide to the highest spots. You can face your staff much better with this instrument than it is possible for a plane to do it, as, in finishing, you use a scraper of steel or glass. A proof staff is an article that should lie in every flouring mill; it is as necessary as a half bushel measure or toll dish. In my examinations of some of our best flouring mills, I have found this instrument wanting, and was much surprised when many good practical miller have told me they never used one. the proof staff requires but to be seen and used once, to be the miller's favorite. They are made in all sizes, to suit all descriptions of millstones, the general price being $25. In those mills that have the proof staff in use, the offals are from two pounds to five pounds lighter per bushel than mills that have not.
The following natural history of the most important of the stone species, was presented us by Mr. J. E. Mitchell, Millstone Manufacturer of Philadelphia. It contains valuable and interesting information for millers, and will be read with pleasing satisfaction by all our American millers; For in "all the stone that this earth" is best, We millers think French Burr the best. Four National Gold Metals have been awarded to Monsieur Roger fils, for the superior quality of his millstones and burr blocks.
An extract from the Report of the National Academy of Paris on the Quarries and Millstone yards of M. Roger fils, at La Ferte Sous Jourarre: The Committee of Arts and Manufacturers of the National Academy of Paris appointed a special Committee to visit the produce of the Manufactory of M. Roger fils, Millstone maker, at La Ferte sous Jouarre. The above Committee, consisting of men of special knowledge, and chosen among the members of the said Academy, hastened to fulfill their mandate, and proceeded forthwith to La Ferte sous Jouarre. The Committee give the following account of their proceedings: "From time immemorial, the millstone of La Ferte sous Jouarre has been acknowledged as being infinitely superior to any other. Various quarries exist in France, Spain, Germany, and in almost all the other countries of Europe, but they are valueless when compared to the working under our present examination. This fact is unquestionable, and is fully established by innumerable experiments; it is of public notoriety that the grinding stones of La Ferte sous Jouarre perform much more work, yield meal much whiter and of much better quality than any others, are enabled to grind to the greatest perfection the corn of every country, and moreover are made so as to last forty to fifty years at least. "These immense advantages insure them preferences wherever they are known, although their price be higher than that of any others; but the results obtained by all intelligent miller do not make the pecuniary question a consideration, for the grinding stones are the principle organs of the mill. We will add that the establishments in the environs of Paris are indebted for the very great repute in which their produce is held, to the exclusive use of the grinding stones of La Ferte sous Jouarre. "This little town, situated in the valley of the Marne, (seine-et-Marne,) and crossed by the latter as well as by the Paris and Strasburg railway, which greatly facilitate the egress of its produce, is surrounded by hills in which are embedded strata of a stone composed of pure silica earth, slightly colored by ferruginous deposits. This is the material which is now used in the composition of good grinding stones, and which, at the same time as it has established the reputation of La Ferte sous Jouarre, has bestowed on France a branch of industry to which every other country is now, and ever will remain, trieutary. "The range of knolls which encircle the town is divided into three principle hills: "To the north, on the left bank of the Marne, rises the Tarterel; to the south, the eye rests on the picturesque hill of Jouarre, separated from the valley of the Manene by the minor Morin, into which it descends; to the west, on the right bank of the Marne, runs the eminence which contains the quarry of La Justice. "The Tarterel itself, contains in general, within its strata, but a light salt gray flint, with large openings, which is no longer in repute in consequence of the improvements made in the art of corn grinding. "But at the foot of the hill, beds of stone are to be found which are deservedly much esteemed. The quarries which are situated on the same line, on this side of the Tarterel, produce a violet and pinkish flint, very appropriate to every system of grinding. The quarries of Bois-des-Cheneaux, in particular, which line the former, and of which the stone is light yellowish, sharp, not brittle, and very strong, is considered as producing first rate materials for grinding stones. "The hill of Jouarre produces a great abundance of grinding stones of various species. It contains good veins, but the strata are in general of little consistence, the beds are not well connected, and the stone yielded, which is a blue slaty color, light blue and gray, is full of small porosities. The quarries of La Ferte sous Jouarre give large quantities of dark blue, light blue, light gray, yellowish gray, and sometimes white flint, with small openings. "The quality of this stone is in very high repute since the introduction of the English system, of grinding. "The valley of the Marne, in the direction of Chateaux-Thierry, and nearly as far as Eqernay, contains several beds of stone which are, at the present moment, is active working. The principle quarries are those of Villieurs-aux-Pierre, Domptin, Charteves, Orbais, Margny, and Les Souvriens. The stone of those quarries, which is mostly of the same quality and color as that of the other quarries of La Ferte sous Jouarre, is principally used in the manufacture of burr stones, and is, in consequence, in great demand for exportation. "It would be extremely difficult to state at what precise period La Ferte sous Jouarre discovered the treasure which was ultimately to afford an easy and honest livelihood to its inhabitants. One fact is unquestionable, namely, that for several centuries past, excavations have been successively made with the most extraordinary good fortune, and that the results of such excavations have been exceedingly productive. "But La Ferte sous Jouarre does not enjoy exclusively the privilege of producing stones for grinding purposes. Some ten or twelve years ago, chance discovered, near the town of Epernon, a stratum of molar quartz, of which the flint, sometimes gray, blue, or white, although does not afford the French millers every quality that is to be found in the stone extracted at La Ferte sous Jouarre, must nevertheless be considered as a formidable rival for its predecessor in the ultramarine countries where it arrives in burr stones; and the activity which is to be witnessed in the quarries of Saint-Lucien and Roches, shows, beyond doubt, that the trade of such stones has become a very important branch for foreign exportation. La Ferte sous Jouarre itself affords a striking proof of the fact, that the stone of Epernon has a very positive merit, since the manufacturers in the former town make use of it for their millstones. "Now that you are acquainted with the various beds of grinding stone, it is important that you should have described to you, as succinctly as possible, the various systems of grinding which have been adopted, up to the present day; because those various systems require severally a special quality of stone, and because it is this requisite that has given to the various quarries the repute into which they have arisen. "In former days, large blocks of stone were extracted from the quarry. These blocks were made into grinding stones of a single piece, or of two or three pieces, grossly put together, and the grinding stones were delivered in this state to the mills. "Such grinding stones had no furrows; but in order that the stones should have a certain sharpness, that which had large cavities, or opening, was selected in preference to any other. "These stones, which were very large and had large openings were called French stones. "Some forty years ago, the English discovered that by cutting in the grinding stones a stated number of furrows, traced so as to facilitate the grinding without thwarting the effect of centrifugal motion, a stone with small openings might be used to advantage, and the circumference of the grinding stone might be considerably decreased, without in any way diminishing the quantity or perfection of the work. This system proved highly successful, and hence the name of English millstones, given to those of this description in France. "The grinding stone manufacturers of La Ferte sous Jouarre, who had at their immediate convenience the best materials, who were acquainted with the wants of the French mill industry, (which has its superiority over that of all Europe,) and who were making wide strides toward improvement and perfection, were very soon able to make English grinding stones. They added to the latter system a third one, consisting of stone having rather large porosities, and which, on the account of the furrows, they called semi-English. But as they were award that it is important, in order that the grinding stone should be softer than the other; that all should have the same grain, the same porosity, the same color, and that consequently in stones made of a single block, chance alone could determine the good or bad quality, they forthwith manufactured grinding stones, made up of a great number of pieces, all exactly similar, taking care to suit their choice to the custom of the country in which the millstones are to work, to the grinding system, adopted by the miller, and lastly to the nature of the grain to be ground. "Since then this business has sprung into an art, the manufacture of millstones requiring quite a special knowledge, and an ability not acquired by everybody. "He begins by the center piece or eye stone, which is most generally of a single piece, and must be of great solidity, particularly for the runner, for it is in this eye stone that the iron cross, by which the stone is suspended, must be fixed. Round this center piece are set and fixed with plaster, the choice pieces previously bound together, and to which, as much as possible, the same thickness in the corresponding angles had been given. These pieces give the grinding stone the circumference it is desired to attain. "At present the joints of these several pieces are made with such nicety and precision, that it is almost impossible to see the stone is not of a single piece. "When the stone has in this manner, reached the required size, it is banded over to the smith, who encircles it by a large hot hoop, to hold the different pieces together; from the smith it passes into the dressing department, where, by the help of rulers perfectly straight, its surface is made even. The latter operation being completed, it passes into the hand of the furrow cutter, who make and traces its divisions, and cuts in its surface a number of furrows, according to the quality of the stone, or to the nature of the grinding for which it is intended. "The next process is to give sufficient aperture to the eye, and then the stopping up process, which consists of filling up the upper face with a sort of masonry, composed of small pieces of millstones and plaster, and thus giving the necessary weigh and thickness. The bed stone does not require to be balanced; this is not the case with the upper one or runner, which, having to revolve on a pivot, requires, as near as possible, its weight to be uniform in all its parts. "As, in spite of all the care that is taken to balance the runner, it might happen that this would not be acquired to perfection, room is left in the stopping up to place a few boxes parallel to each other. These boxes are intended for lead, when in the mill a perfect equilibrium of the grinding stone is requisite before the latter can be applied to their work.
Note: The fitst edition of The American Miller and Millwright's Assistant, by William Carter Hughes, was published in 1850, by Harsha and Hart, Detroit.
