A method of artificially producing the coloring matter of the madder plant, known under the name of " alizarin," has been recently discovered by Messrs. Graebe and Liebermann, of Berlin. The extraction of alizarin from the madder root was effected some time ago by Mr. Kopp, whose process was as follows : He heated the powdered madder with a watery solution of sulphurous acid (SO), which extracted two coloring matters, the alizarin and purpurin, with other substances. When this solution was heated to 133 Fah. a precipitate, consisting of almost pxtro alizarin, was deposited. On filtering the solution and heating it ag'ain to 313 Fah. the sulphurous acid was all cspoUed, and the solution conBsquently lost its ability to retaiH iin; second oloiing matter OT porptir-n, which Wae therefor? n(Jipitateili The two fioorifjg tkjuirt mesieaed pwpacd on Wasselonne, France, and supplied to cotton manufacturers for dyeing and printing. The coloring matters obtained from coal tar have the property of removing all other coloring matters except indigo, cochineal, and madder. Strange to say, the chief coloring matter of the last is now produced from coal tar itself. On distilling coal tar, volatile and fixed oils are obtained which boil at from 86 to 572 Fah. Among the latter is found a hydrocarbon, called " anthracene," the formula of which is C28 Hjj. From this substance was obtained alizarin, previously only found in the root of the madder. The method of producing alizarin was first made known by the publication of the French patent, the particulars of which will be here narrated, with additional observations on the manner in which the formation of the alizarin can bo effected. In the introductory remarks respecting the patent, it is stated that alizarin is the chief coloring matter of the madder that dyers, and especially calico printers employ to dye their goods rose, pink, violet, brown, and black, according to the kind of mordant made use of in the operation of print-ing. It is also asserted that the prepared madder, called goraneen {fleurs de ga/rcmce), is consumed to the extent of thousands of tuns yearly. In modern times also the pure coloring matters were extracted from the madder and used in dyeing and printing operations. The process discovered by Messrs. Graebe and Liebermann, of Berlin, consists in the production of alizarin without the employment of madder, and in an entirely new way. The process presents three different stages. In the first place the hydrocarbon called anthracene, already alluded to, is employed as the raw material. For some time past the antracene, or parapraphthalin, ha been obtained from the destructive distillation of coal tar. This anthracene must be transformed in the first stage of the process into a substance containing more oxygen than itself; namely, oxanthracene, or anthrachinon. This substance has been already obtained by other chemists by heating anthracene with nitric acid, and then purifying the product by distillation, when it presents itself in the form of yellow needles. Messrs. Graebe and Liebermann, however, effected the transformation of anthracene into anthrachinon in the three following ways : In the first process the anthracene is treated with a solution of bichromate of potash,and then treated with sulphuris acid, until all the chromic acid is reduced to peroxide of chromium. AS regards the relative quantities of the two substances made use of, one part of anthracene is treated with two parts of bichromate, and the necessary amount of sulphuric acid afterward added. Any other Chromate may be employed instead of the bichromate of potash. The oxanthracene, or anthrachinon, thus obtained appears as a solid, insoluble brown mass. In the second process, two parts of bichromate of potash are heated with one part of anthracene, and about fifty parts glacial acetic acid, until aU the chromic acid is reduced. When cold, the anthrachinon is found in the same form as in tho preceding process. Some of the anthrachinon which remains dissolved in the acetic acid, may be obtained by distilling the latter. In the third operation a mixture of anthracene and glacial acetic acid is heated to 176 Fah., and heated with nitric acid, which must be added a drop at a time. The relative quantities of the two substances employed are one part of anthracene to one part of nitric acid. In this process the anthracene is converted into a substance richer in oxygen than itself, the formula for anthracene being Cja Ho, while that of the oxanthracene is Cgg Hg O2. In the second stage of the operation the oxanthracene is heated with bromine, when two equivalents of hydrogen are replaced by two equivalents of the latter, and a substance is formed which has the composition Cjg Hg O3. To obtain this substance the anthracene is placed in a sealed tube, with two equivalents of bromine, and heated ten hours at a temperature of 176 to 266 Fah. The hydrobromic acid formed during the operation can be removed by leading the gases into a solution of some alkali. A crystalline mass is found in the tube, which has to be purified by tecrystalliza-tion. This substance has the composition Cgg Hg 0. It may be obtained likewise in the following way : Eight equivalents of bromine are allowed to act upon one equivalent of anthracene (Cgg HJQ), when a substance is formed having the composition C. Hg Bg, and which appears in the tube as a crystalline mass. On treating this substance with an alcoholic solution of potash it is transformed into an anthracene in which four equivalents of hydrogen are simply replaced by four equivalents of bromine. The formula therefore of this new substance is as follows : Cjg Hg. When this last is treated with any oxidizing agents a new substance is formed, two equivalents of bromine replacing two equivalents of oxygen, so that the new sitbstance has the composition C28 Hg O,. This is the so-called bibromide of anthrachinon. B. By employing chlorine instead of bromine an analogous substance is formed, in which two equivalents of chlorine havR replaced two equivalents of hydrogen. This is the bi-chlortde of anthrachinon, as its discovererfs call It. Its J(D gc Hj O3, TWg BvtbttMic is treated with * o# 55 of from 356 to 500 Pah., ?when the liquid becomes blue. When the formation of this blurf substance is completed the liquid is allowed to become cold, and the substance is then extracted by water. This is a salt, iu which an organic acid is united to potash. On heating the bichloranthrachiuon (Cjg Hg Oj) with an alkali, the chlorine is replaced by hydrogen, and six equivalents of water are at the same time added to the composition of the new substance (Cja He 0,) + 3 KG H0+30=3KC] +(C.,s Hg O) CU The substance Cjg Hj Og is still in combination with the alkali, but can be separated from the latter by adding an acid to the alkaline solution, when a yellow precipitate results.; This yellow precipitate is found to be pure alizarin, and can be employed in dyeing and calico printing. Experiments were made in the manufactory of Messrs. Liebermann, of Berlin, to test the efficacy of this artificial alizarin, and the results were extremely satisfactory. It is to be regretted, however, that this interesting discovery of Messrs. Graebe and Liebermann has hitherto been turned to little practical account. In the first place the anthracene, or raw material from which the alizarin is extracted, is very difficult to obtain. The coal oils contain only very minute quantities of anthracene. But then the same method which was employed to produce aniline may be chosen. But even the aniline was found in such small quantities in the tar that the employment of aniline would be far less extensive than it is iu the present day if this were its only source. The labors of Zinin, Bchamp, Hitscherlich, and others, taught us to prepare aniline from benzole, a substance abounding in the elements of tar. The same synthetical method must be employed to obtain anthracene. Messrs. Limpericht and Berthelot showed that anthracene can be prepared synthetically. To prepare aniline toluen, a hydrocarbon consisting of 4 Hg, is heated with chlorine and then decomposed at 393 Fah. by the vapor of water, or the toluen is conducted toluen. anthracen. through a tube heated to redness [3 Cj H8] = C28 'Bg + QB.. The possibility of forming anthracene synthetically is shown in our laboratories. Why, then, should it not be used to produce alizarin on a large scale ? It is, of course, necessary that the new preparation or artificial alizarin should be cheaper than the alizarin extracted from the root of the madder. One considerable obstacle to this is, that alizarin obtained from madder is already prepared on a large scale in Prance. But, after all, the new discovery must be considered as an important step in the art of manufacturing colors, and it is sincerely to be hoped that the c.ew method of preparing artificial alizarin will soon be cheap enough to allow of its general employment in dyeing and printing. On Iacqnerlng, The Painter, Gilder, and Varnisker's Companion gives the following recipes : LACQURE FOR BRASS. Seed-lac, six ounces; amber or copal, ground on porphyry or very clean marble, two ounces; dragon's blood, forty grains; extract of red sandal wood, thirty grains; oriental saffron, thirty-six grains; pounded glass, four ounces; very pure alcohol, forty ounces. Articles, or ornaments of brass, to which this varnish is to be applied, should bo exposed to a gentle heat and then dipped into the varnish. Two or three coatings may be thus applied, if necessary. Articles varnished in this manner may be cleaned with water and a bit of dry rag. LACQTJBE POE PHILOSOPHICAL INSTRUMENTS. Gamboge, an ounce and a half; gum sandrac, four ounces; gum elemi, four ounces; best dragon's blood, two ounces; terra mrita, an ounce aud a half; oriental saffron, four grains; geed-lac, two ounces; pounded glass, six ounces; pure alcohol forty ounces. Terra mrita is the root of an Indian plant; it is of a red color, and much used in dyeing. In varnishing, it is only employed in the form of a tincture, and is particularly well adapted for the mixture of those coloring parts which contribute the most towards giving metals the color of gold. In choosing it be careful to observe that it is sound and compact. The dragon's blood, gum elemi, seed-lac, and gamboge, are all pounded and mixed with the glass. Over them is poured the tincture obtained by infusing the saffron and terra mrita in the alcohol for twenty-four hours. This tincture, before being poured over the dragon's blood, etc., should be strained through a piece of clean linen cloth, and strongly squeezed. If the dragon's blood gives too high a color, the quantity may be lessened according to circumstances. The same is the case with the other coloring matters. This lacquer has a very good effect when applied to many cast or molded articles used in ornamenting furniture. GOLD-COLOEBD LACQUBE POE BRASS WATCH CASES, WATCH KEYS, BTC. Seed-lac, six ounces; amber, two ounces; gamboge, two ounces; extract of red sandal wood in water, twenty-four grains; dragon's blood, sixty grains; oriental saffron, thirty-six grains; pownded glass four ounces j pure alcohol, thirty-Six ounfies. The eed'lae, aintter, gwMs iid dfgoa's Moo must fcg with the pounded. glass. Over this mixture is poured the tincture formed by infusing the saffron and the extract of sau-al wood into the alcohol, in the manner directed in the last receipt. The varnishing is completed as before. Metal articles that are to be covered with this varnish are heated, and, if they are of a kind to admit of it, are immersed in packets. The tint of the varnish may be varied in any degree required, by altering the proportions of the coloring quantities according to circumstances. TO MAKE LACQUEE OF VAEI0U8 TINTS. Put four ounces of the best gum gamboge into thirty-two ounces of spirits of turpentine; four ounces of dragon's blood into the same quantity of spirits of turpentine as the gamboge, and one ounce of anatto into eight ounces of the same spirits. The three mixtures should be made in different vessels. They should then be kept for about a fortnight, in a warm place, and as much exposed to the sun as possible. At the end of that time they will be fit for use; and you can procure any tints you wish by making a composition from them, with such proportions of each liquor as practice and the nature of the color you are desirous of obtaining will point out. TO CLEAN OLD BRASS WOEK POE LACQUBEING. First boil a strong lye of wood ashes', which you may strengthen with soap lees; put in your brass work, and the lacquer will immediately come off; then have ready a pickle of aqua f ortis and water, strong enough to take off the dirt; wash it immediately in clean water, dry it well and lacquer it. The Fat-aday Iectures—Receptlou of Dumas In ]:ngland. A crowded meeting of Fellows of the Chemical Society and their friends, including many ladies, was held in the Theater of the Royal Institution of Great Britain on Thursday, June 17, Mr. Dumas (the Faraday of France) having been invited to deliver the inaugural address. The chair was occupied by Prof. Williamson, F.R.S,, who briefly explained the nature and object of the lectures which it was intended to inaugurate, concluding by presenting Mr. Dumas, on behalf of the society of which he is president, with a large gold medal, which he stated in a few appropriate remarks (in French) had been specially struck in commemoration of Mr. Dumas' visit to this country. Mr. Dumas having acknowledged the high honor that had been conferred upon him by selecting him as the representative of the samans of his country, delivered a brilliant and eloquent discourse, iu which he traced the progress of discovery in chemical science from the time of the ancient Greeks until now, and compared the knowledge which they possessed with that which modem research had placed us in possession of. He remarked that the ancient Greeks recognized only the four elements—earth, air, fire, and water; but although they had thus distinguished them from each other, they had left everything to be discovered concerning them, rich as their materials were for the making of discoveries. The action of these elements the Greeks perfectly understood; but it was left for Lavoisier to teach us how to understand nature more completely. The elements of Lavoisier were those which were irreducible, and so far as the principle was concerned his views were still adopted, but while Lavoisier could only recognize thirty-one elements, subsequent researches had discovered no less than thirty-five new ones. He referred to the researches of Dr. Dalton and Dr. Prout, and to the views entertained as to the atomic numbers being exact multiples of a standard number, urging that all elements were but varied combinations of some primary element with which as yet we are unacquainted. The remarkable nature of the progression of the numbers representing the atomic weights of elements of the same class was, he was convinced, not the result of mere accident. There was lithium, with its number 7; sodium, 33; and potassium, 39—each progressing by the number 16. Then, again, there was magnesium, 13; calcium, 30; and iron, 38—each progressing by the number 8, or the half of 16, which was certainly a most remarkable fact, and tended, in connection with our other knowledge, to show how much we have still to learn. Referring to Faraday's researches in connection with the natural forces, he observed that it was Faraday who had shown the correspondence of electricity, magnetism, light, and heat; and that it was Faraday that had taught them that chemical affinity obeyed the same laws as those of physics. Newton foresaw much, but Faraday demonstated it. Newton I discovered the law of universal gravitation; and to show how I little they knew even now he would say that there was no one present at that meeting, at which the strongest lights of the science of England were represented, who could tell them anything of the cause of that universal gravitation. He thep traced the effects of light and heat upon organized beings, and our ignorance of the cause of those effects, pointing out the enormous field which was open for future; investigation. At the conclusion of the discourse, Dr. Tyndall, as an old student of Dumas, moved the cordial vote of thanks of the I Chemical Society to him for having inaugurated their Faraday Lectures, remarking that the impression which Dumas had produced upon his mind when as a student he first heard him at the College de France, nearly twenty-five years since, led him to think that he was then a!t the znith of his power; but the discourse they had heard that evening had convinced him he waa mistaken, for his vigor aind eloquence now surpassed anything he had heard frcfm him many years ago. The Tote Was cari*ied With alamatiou, and having heen aelsnowledgvj wih vmsb eirtoooi "hf Dttreftgi tha mming lInamelInK and Polishing. In speaking of enamel it must be understood as polished ' paint on the surface of woodwork, such as doors, architraves, I window shutters, etc. Enameling and polishing is an art which requires the exercise of the greatest care and patience in its execution. A little carelessness orinattention at the fin-ish may undo the work of days. The work will not bear any; hurry, either in the material or labor, but must go through its regular course,have its proper time to darken between each coat and process; and the rabbing down must be patiently and gently done—heavy pressure will only defeat the end iu view. Great care should be taken in the selection of the pum. ice stone, both lump and ground, as the slightest particle of grit or hard pressure will scratch, and thus cause hours of la. bor to be thrown away. In describingthe material used for the purpose.we shall only describe that which we consider best suited for getting up the white or light-tinted enamel. There are several kinds of fill, ingup color used and sold by the colormen.but most of them are of a dark color, not suited for light work, as they require so many coats of paint afterward, to get a pure body o color that it defeats its own object. In practice, we find it best to fill up from the first with the same tint of color we intend to finish with, thus forming a solid body of pure color, which will bear much rabbing down without being shady. For all dark grounds, which have to be finished a dark color, the black or dark filling is the best. The tools and material required are as follows, viz; 1, White lead ground in turpentine, and best white lead in oil. 3, A clear, quick, and hard-drying varnish, such as best copal, Mande Brthen' white eobarg, and white enamel varnish, etc, ete, 3, Ground and lump pumice stone, or putty powder, 4. Rotten stone, ground in water or oil, 5, Some white felt, from a quarter to a half inch iu thickness, and of the best quality, 6, Several flat wooden blocks, of various sizes and forms, suitable for getting into corners and moldings; these must be covered with the felt on the side you intend to use, 7. Two or three bosses, made with cotton wool aud covered with silk. 8. Sponge, and wash or chamois leather. In order to simplify the description we will take a plain panel to work upon. If it is new, give it two coats of oil color, mixed in the ordinary way; now mix the white lead ground in turps with only a sufficient quantity of varnish to bind it with,thinning to a proper consistency with turps. It is as well to add a little of the ordinary white lead, ground in oil, as it helps to prevent cracking. Give the panel four or five coats of this mixture leaving a sufficient interval between each coat to allow it to dry well. Let it stand for a few days, until it is hard enough to rab down,When it is ready, you may rab it down, first with a soft piece of lump pumice stone and water,to take off the rough parts. Now use the felt and ground pumice stone and cut it down,working the hand in a circular form or manner. You will require to exercise much care and patience to rub it down to a level surface and without scratches. When you have got it downlevel,if it is scratched or not sufficiently filled up, give it one or two more coats, laying it on as smoothly as you can, and rub down as before. If done properly, it will now be perfectly smooth, level, and frea from scratches; wash well down, and be careful to clean off all grit or loose pumice stone, Now mix flake white from the tube with the before-named varnish, till it is of the consistency of cream. Give one coat of this; when dry give another, adding more varnish to it. Now, let this dry hard, the time for which will of course de-pend upon the drying qualities of the vamish; some will pol-ish in eight or nine days, but it is much the best to let it stand as long as you possibly can, as the harder it is the brighter and more enduring will be the polish. When it is sufficiently hard, use the felt and very finely ground pumice stone and water; with this cut down till you get it perfectly smooth; now let it stand for a couple of days to harden the surface, then take rotten stone either in oil or water, use this with the felt for a little while, then put some upon the surface of the silk boss, and gently rub the panel with it, renewing the rotten stone as required. It is always better to rub in a circle than straight up and down, or across. Continue this until you have got it to a fine equal surface all over; it will begin to polish as you go on, but it will be a dull sort of polish. Clean off—if the rotten stone is in oil, clean off withdry flour; if in in water, wash off with sponge and leather, taking care that you wash it perfectly clean, and do not scratch. You will now, after having washed your hands perfectly clear, use a clean damp chamois leather, holding it in the left hand, using the right to polish with, keeping it clean by frequently drawing it over the damp leather. Now use the ball of the right hand press gently upon the panel, and draw your hand forward or toward you; if you do this properly, it will bring up a bright polish on the work, and every time you bring your hand forward a sharp shrill sound or whistle will be produced, if this is the case, you may be sure you are in the right path. Continue this until the whole surface is one even bright polish. It will be some time, and will require much practice, before you will be able to do this in the best manner; but with perseverance and practice the difficulty will soon vanish. A soft smooth skin is best for polishing; if it is very dry and hard it is apt to scratch. The latter part of these instructions referring to the polishing, will of course, apply to polishing up on imitation woods and marbles, or on any polishing varnish, using the varnish pure, of course.—London Building News. The good Conductor of heat is the good conductor of elee tricity, and the ha eMt of. Is the ha codiction of electricity