Hydro-iridio-cyanic Acid (Ir2Cy33 HCy).—This body is obtained in crystalline crusts when the iridiocyanide of barium is precipitated with sulphuric acid, and the residuum is recovered by ether. It is soluble in water and alcohol, but sparingly in ether. The solution with the addition of hydrochloric acid gradually deposits a green precipitate of sesquicyanide of iridium. MM. Wöhler and Booth have obtained the salt of potassium.† It is very soluble in water, but insoluble in alcohol. Its crystals, which are very beautiful, belong to the class of right rhomboidal prisms. They are anhydrous. The barium salt (Ir2Cy33 BaCy+18HO) is very soluble in water and insoluble in alcohol. The iridio-cyanides precipitate salts of copper, blue; those of mercury, zinc, protoxide of iron, white; of peroxide of iron, yellow. those The composition of rhodio-cyanides is analogous to that of the iridio-cyanides. M. Claus has prepared the potassium salt by melting double chloride of rhodium and ammonia with cyanide of potassium. Concentrated acetic acid decomposes this salt, disengaging hydrocyanic acid and depositing sesquicyanide of rhodium. Iridio-cyanide of potassium not decomposing under the same circumstances, this reaction can be made useful in separating iridium from rhodium. Cyanide of Rhodium, Rh2Cy3, a beautiful carmine red powder, soluble in cyanide of potassium, and decomposable by heat, leaving a residuum of metallic rhodium. The author adds a few observations on the platinum eyanides. He describes a double platino-cyanide of potassium and sodium (KCy.NaCy.2PtCy + 6HO), which crystallises in oblique rhomboidal prisms of a beautiful orange yellow, a platino-cyanide of cinchonine in white crystalline needles, a platino-cyanide of cadmium, CdCy.PtCy, obtained by precipitating the salt of Gmelin by chloride of cadmium. The latter cyanide is crystalline, and of a yellowish colour. It is soluble in ammonia, forming with this base a salt Notes on Benzoylnaphthylamide, by A. H. CHURCH. WHEN naphthylamine, in fine powder, is warmed gently with its equivalent of chloride of benzoyle, hydrochloric acid gas is evolved, and in accordance with analogy in the case of aniline, benzoylnaphthylamide formed. The crude product is washed with water, then with a solution of carbonate of soda, and finally re-crystallised from boiling absolute alcohol. On cooling, the solution solidifies into a mass of flattened needles. These crystals are odourless and colourless, and, unlike most naphthylamine compounds, are not darkened by exposure to the light and air. When heated they fuse into a colourless oil, which solidifies without crystallising. They gave on analysis numbers closely according with the formula : Poggendorf's Annalen der Physik und Chemie, vol. xxxi. p. 161. CHO N. Dibenzoylnaphthylamide. Chloride of cumyle, chloride of succinyle, and chloride of sulphophenyle, act energetically upon naphthylamine. According to analogy, the several products, none of which I have as yet analysed, should be :— C10H110 CH, N. Cumylnaphthylamide. HJ Contributions towards a Knowledge of the Inorganic Experiments with Fluorine. Fluorine has been found in animal and vegetal bodies, by Berzelius, Erdmann, Marchand, Heintz, G. Wilson, T. J. Herapath, Nickles, and other chemists. In animal bodies it is found in greatest quantity in those partssuch, for instance, as teeth and feathers-in which silicic acid and phosphoric acid abound. It is rarely found in estimable proportions; thus, Wilson found mere traces of it in the ashes of twenty-four pints of blood, of twelve pints of milk, and of twelve pounds of cream cheese. Fluorine enters so sparingly into the composition of animals and plants, that it is difficult to believe in its importance to those organisms. Its presence in them is, in all probability, accidental, and arises from the circumstance of its being almost invariably associated in the mineral kingdom with silicon and phosphorus, which, on being taken up, as they are in large quantities by plants, carry with them a trace of fluorine. In like manner the iron taken up by plants carries with it into the vegetal mechanisms a little of its kindred metal and frequent companion-manganese. The ashes of the plants which grew in the vessels of groups a, b, and e were carefully examined for fluorine with negative results. The quantities operated upon were, however, too small to enable me to state positively that they did not contain very minute traces of fluorine. CHEMICAL NEWS, Į The Inorganic Constituents of Plants. Conclusion. 325 me that too much importance is given to the difference The investigations, the results of which I have now in the composition of the ashes of various kinds of plants. had the honour of submitting to the Royal Dublin Excepting those plants, such as the Gramineæ and the Society, have occupied a large portion of my time for Equisetæ, which contain a large quantity of silica for several years past, but particularly during the years mechanical purposes, there is, after all, but little differ1858 and 1861. To ensure the accuracy absolutely ence between the composition of the ashes of all our necessary in experiments of this kind, the greatest care cultivated plants. How often do we not find a greater had to be exercised in the preparation of the substances difference in the composition of two specimens of the employed in which the plants were grown, and in the same plant than in the composition of two plants belongperformance of the analyses of their ashes. The limits ing to different species? That sea-weeds contain a large to which this paper is restricted by the rules of your amount of sodium compounds is no proof that soda is Society, oblige me to be so concise in my descriptions the alkali they prefer. They are constantly moistened that I cannot enter into the details of the methods which with sea-water, of which sodium is the most abundant I adopted in analysing the ashes of the plants experi- constituent. Ought we not rather to consider potassium mented upon; I can, therefore, give but a mere outline as the alkali essential to sea-weeds, since, when watered of the procedure. Great care was taken in separating with a fluid containing thirty times more sodium than the plants from adhering earthy matter, and the cleaning potassium, they absorb from it both elements in nearly of the seeds was effected according to the plan recom- equal proportions? Were potassium the preponderating mended by H. Rose. As it was of importance that there ingredient of sea-water, I have no doubt the amount of should not be the smallest loss of the alkaline chlorides sodium existing in sea-weeds would be exceedingly small. (which are so likely to be volatilised if exposed to a high The opinion of the late Dean (Herbert) of Manchester, temperature), Cailatt's mode of removing the organic that plants do not grow naturally in the soils best suited constituents, by the action of dilute nitric acid, was, in to them, absurd though it may at first sight appear, is, most instances, adopted. By this method the incinera- after all, not very far from the truth. "I saw," said the tion of the residual parts of the plants is effected at a com- sagacious Dean, "a crocus, a sternebergia, and an orniparatively low temperature, and the amount of ashes thogalum, growing in contact with each other aloft on obtained is greater than when the combustion is effected the meagre soil of Mount Enos; but not a seed-pod of by the old way,-i.e., by burning the substance in a the sternebergia could be discovered, and very few of crucible placed in an oblique position. In a few instances the crocus. In a more fertile soil they would have been the incineration was effected in a muffle, according to choked by some stronger plant, but they would rejoice Strecker's modification of Erdmann's plan. The vegetal in a better soil if protected against the oppressor." The and animal substances were first merely charred at the Dean contends that the reason why certain plants are lowest possible temperature, and exhausted of all their found in peculiar situations is not because they prefer constituents, which are soluble in water and dilute hydro- them, but simply because they alone are capable of chloric acid. The incineration was then completed, and existing there, or because in more favourable places they the ashes examined by the most recent and improved would be overcome by more vigorous plants. I am almost methods. disposed to adopt the Dean's theory in its entirety. Do we not see the furze flourishing in places where the wheat, the pea, or the cabbage would speedily perish; yet who can doubt that the furze thrives still better when cultivated in a kindly soil? The bare rocks to which the algæ cling are sterile to the cultivated plants; but what chance of existence would the soft mass of cells which form these vegetal mechanisms have, if surrounded by such firm, hardy plants as the thistle, the sweet-briar, or the cabbage? It is not the partiality of the sea-weeds for soda, which is the cause of their growing only on the coast; it is because their low organisation permits them to live upon the coarse fare supplied by the ocean, and to be developed under other conditions of existence, which would speedily prove fatal to plants higher in the scale of vegetal life. It is my intention to prosecute still further inquiries into the nature of the inorganic constituents of plants; and the problems which appear to me to be ripe for solution, and which I shall make an attempt to solve, are the following:: I. Whether or not magnesia can be wholly substituted for lime. II. Is iron absolutely necessary to plants, or may manganese replace it? III. May chlorine, which is so constantly present in plants, be replaced wholly or partly by bromine or by iodine, or by fluorine ? IV. Are bromine and iodine essential ingredients of marine plants?+ I am not vain enough to suppose that the results of my investigations, however elaborate and extensive they may be, will solve these important problems; their complete and satisfactory solution can, indeed, only be accomplished by the labours of many chemists, and by the careful performance of a large number of experiments. The more I study this subject the more I am disposed to believe that many of the mineral substances found in plants are either wholly useless, or are present in greater quantity than is necessary or useful. It also appears to * Chlorosis is a disease not confined to animals; for, according to E. Gris, chlorotic plants (Castanea Americana, Quercus phellos, &c.) were cured by watering them with a solution of protosulphate of iron. It is probable that neither bromine nor iodine is essential to vegetables. That they are constantly present in marine plants, is simply because they are carried up into them by the alkaline metals; but if both of these palogens were completely removed from the ocean, I have no doubt their absence would in nowise affect the vegetation of the coast. In concluding this paper, I have to acknowledge my obligation to Mr. Emerson Reynolds for his assistance in carrying out some of the details of the investigations described therein. [In the foregoing paper, the new unitary system of chemical notation has been employed-a system which, from its simplicity, deserves to be generally adopted.] Bicarbonate of Ammonia.-Schrötter found a mass of crystals in a cast-iron pipe through which raw gas passed, which on analysis proved to have the composition NHO,2CO,+HỎ. Before the analysis was made the crystals were cleaned from coal-tar with which There is no they were soiled, and were resublimed. doubt, then, of the existence of a true bicarbonate of ammonia.-Sitzungsrb. d. Akad. d. Wissenschaf, zu Wien, Bd. xliv., s. 33. PHYSICAL SCIENCE. On the Action of the Voltaic Pile on Salts of Potash and Soda, and Alloys submitted to Igneous Fusion, by M. GERARDIN. M. GERARDIN has just completed, in the laboratory and at the expense of the Duc de Luynes, a long series of experiments on the electrolisation of salts and alloys submitted to igneous fusion. We have space only for his principal conclusions, and for some simple and easy experiments in support of them. 1. In the electrolytic decomposition of potash and soda salts submitted to igneous fusion the oxygen alone goes to the positive pole, the two radieals of the acid and of the base going to the negative pole. By plunging the poles of the battery into a crucible containing fused borax, an abundant disengagement of oxygen takes place at the positive pole, and at the negative pole bubbles of sodium which burn on the surface. After the experiment the negative pole is found surrounded by a considerable deposit of amorphous boron. 2. The presence of excess of alkali does not vitiate the results, and imparts the advantages of conductibility and fluidity, which admit of the operation being performed with batteries of from one to four ordinary elements of Bunsen, and in ordinary furnaces. Platinum poles are much less attacked than in operating at a higher temperature without the addition of alkali. All the salts of potash and soda can be decomposed in this manner with the greatest ease. M. Gerardin has operated upon borates, silicates, zincates, stannates, chromates, manganates, titanates, molybdates, uranates, aluminates, arseniates, arsenites, antimoniates, phosphates, sulphates, carbonates, and nitrates, and in every instance oxygen only was disengaged at the positive pole. The decomposition of uranates and phosphates furnish the best experiments. With uranates globules of potassium or sodium appear at the negative pole, and detonate in the midst of a shower of uranium sparks. With phosphates, when the current has ceased to pass there is a brilliant combustion of phosphorus at the negative pole at the termination of the experiment. Chlorates alone are the exception to the rule. Chlorine and oxygen are disengaged simultaneously at the positive pole. But this anomaly may be attributable to the decomposition of chloride of potassium, which takes place when the heat has begun to decompose the chlorate of potash. 3. Bodies which tend together at the negative pole are in a state of mixture rather than in a state of combination. The proof of this lies in the absence of phos phuretted or siliciuretted hydrogen in the decomposition of phosphates or silicates, to which is added potash, which is always hydrated. The combustion of phosphorus after the decomposition of phosphates is a further incontestable proof of this proposition. 4. The poles are often attacked. Thus, if in decomposing silicates an ingot of aluminium is taken as the negative pole, the aluminium alloys itself to the potassium and sodium set free. In presence of water this alloy yields spontaneously inflammable siliciuretted hydrogen. 5. During the decomposition of chlorides, bromides, iodides, sulphides, &c., the positive pole is energetically attacked, and the compound formed decomposes a short time after, under the influence of the current. Thus, by placing a positive copper pole in a crucible containing fused sea-salt, it will be observed that, after the passage of the current, half the crucible will take a greenish-blue colour, from the chloride of copper, and the other half red, from the metallic copper. With iron poles the action is more complex; for the sea-salt attacks the oxide of iron unless hindered by the action of the current. On this point the Duc de Luynes has performed an excellent experiment, hitherto undescribed. He threw some pieces of iron into a crucible containing fused sea-salt, and filled up the crucible with pieces of earthen crucible. Chloride of iron forms, which, under the influence of humid air, is transformed into oxide, the earthen pots at the same time becoming covered with a multitude of crystals of oligist iron, identical with those of the Island of Elba. 6. The electrolytic decomposition of compounds formed at the expense of the poles is not identical in the dry and the wet way. Thus, when copper poles are used, if the same current is passed into fused or dissolved sea-salt, there results in the first place chloride of copper and reduced copper, and in the second place, hydrate of suboxide of copper, of a beautiful yellow colour. 7. When several bodies are fused together, their electrolytic decomposition is not simultaneous, but successive. Thus, in the decomposition of uranates, sparks of uranium appear before the bubbles of potassium. This is attributable to the reducing action of bodies with strong on those with weak affinities. This is easily proved by dissolving oxide of copper in fused borax. When the borax is nearly solidified the bubbles of sodium detonate slowly, and the blue colour imparted to them by the dissolved oxide of copper will be superseded by the red of the reduced copper. 8. All alloys, without exception, lose their homogeneousness when traversed by the current. Thus, fused plumbers' solder when electrolysed becomes brittle at the positive pole and soft and malleable towards the negative pole. The amalgams and alloys of potassium and sodium can be operated upon when cold. The amalgam of sodium decomposes water when taken at the negative pole, but not at the positive. Potassium and sodium alloy, under the influence of the current, solidifies at both poles. 9. Whatever the electro-chemical rank of a metal, if present in small quantities in the alloy, it goes always to the negative pole. The amalgams of gold and bismuth dissolved in mercury may be taken as examples. Whatever the amalgamated metal, it always returns to the negative pole.Comptes-Rendus. INTERNATIONAL EXHIBITION. CLASS III. Substances used as Food. (Continued from page 319.) A SIMPLE exhibition of substances used as food is by no means a satisfactory or, rather, satisfying display. The special organ which desires to be satisfied has no chance of gratification; and thus the mere sight of the richest bride-cakes under close glass shades, the most tempting of bon-bons in impervious glass cases, the neatest of wines in sealed bottles, and the brightest of ales in untapped barrels (which last, by the way, might as well be filled with water), is little better than a CHEMICAL NEWS, 1 Royal Institution of Great Britain. mockery, if it be not altogether a delusion. We may say, indeed, that the only satisfactory display in this division is the case of Dr. Hassall (788), a sight of the contents of which is enough for a visitor. We are almost tempted to ask how the Doctor could have got possessed of all these abominations. Did he really find those Bath buns coloured with chromate of lead exposed for sale at a pastrycook's? Are all these poisonous delicacies in common use, and intended by their makers to be eaten? We might ask many other questions concerning the contents of this case, but this is not the place; we may, however, inquire whether, if people will buy lozenges and things of that sort at less than the cost of sugar, plaster of Paris, or flour, can reasonably be considered an adulteration? There are a few novelties in this division which deserve particular notice. There is, for instance, the uncooked preserved meat exhibited by Messrs. Jones and Trevithick (795). Of all the means devised for protecting organic matter from that arch promoter of decomposition, oxygen, Mr. Jones's plan would seem to be one of the best. He places the material to be preserved in air-tight vessels, effects the complete exhaustion of the atmospheric air, and then replaces it with pure nitrogen. How far the plan is successful may be seen by the specimens exhibited. Here are a leg of mutton, a piece of salmon, and some sausages. Warmth and moisture have evidently done their best to bring about decomposition; but the active agent of change being absent, they seem to remain quite unaltered. There can be no doubt of the success of this plan if it be perfectly carried out; but it will be expensive, we imagine, and leave a large field open to Mr. M'Call (802), who exhibits preserved cooked meats close by. Mr. M'Call adopts the old plan of expelling air by boiling, but he adds an ingenious contrivance of his own. All who have been condemned to live on preserved meats are well aware that a little decomposition almost always takes place in them; and few who eat them escape without more or less diarrhoea. Probably the air is never completely replaced by steam in the boiling, or some air may make its way again into the cases before they are soldered down; so Mr. M'Call has a plan by which he expects to effect the absorption of any oxygen remaining in the case. In the top of his cans is a small capsule in which he places a button of fused hyposulphite of soda, which, by a peculiar contrivance, is exposed when the can is soldered, and becoming dissolved is expected, by the decomposition familiar to chemists, to absorb any oxygen left in the vessel. Whether it really does so we will not undertake to say, but, at all events, the case of beef open on the table is quite free from taint, and looks remarkably good. 327 ceeded in getting his glucose into an agreeable looking granular condition, very much like honey, and there is now no legal objection to its general introduction. Mr. Garton here exhibits specimens in the various stages of manufacture, and also samples of beverages made with his grape sugar in place of malt. Every practical chemist will see how much these may be made to surpass those produced in the ordinary way, and how large a field is open to the employment of this material. The strongest ales may be brewed having very little more colour than the decoction of the hops; the British brandy maker may now equal his Continental rival at Cognac ; and the maker of perfumes will find a spirit quite free from any other odour than its own. British wines, too, will lose some of their objectionable qualities if fermented with this glucose. We may pass over most of the remaining exhibitors in this class with a very few words. No doubt the ales of Messrs. Salt and Co. (874) and Bass and Co. (853) fully sustain the reputation of these brewers; but the visitor must exercise his faith, for the barrels are untapped and the bottles are sealed. Messrs. Fortnum and Mason have a very fine display of preserved fruits and other good things for which they are famous. In case 783 Messrs. Fry exhibit all sorts of cocoa and chocolate preparations, from the stump of a cocoa tree to the finished chocolate bon-bons; and in 776 Messrs. Dunn and Hewett display a similar collection to which they scientifically add a specimen of theobromine, the only one we have yet seen in the Exhibition PROCEEDINGS OF SOCIETIES. ROYAL INSTITUTION OF GREAT BRITAIN. A Course of Six Lectures on Some of the Chemical Arts, with LECTURE II. (Thursday, May 15, 1862.) I MUST now make a little recapitulation of our last lecture, and show you the manner in which its waste products are applied to useful purposes. I explained to you that gas was produced by the distillation of coal; that for a long time the thoughts of manufacturers were applied only to the first purposes for which coal was used, namely, the production of the gas; and that all the substances which are accessory products were looked upon in the light of concomitant evils, the tar and water being waste products, which were inconvenient, and to be got rid of by the most ready methods. Long ago, in the seventeenth century, Boyle wrote an Essay entitled, "Man's Great Ignorance of the Uses of Natural Things; or, that there is no one thing in nature whereof the use to human life is thoroughly understood." This truth of the seventeenth century is still a truism in the nineteenth century, the whole progress of manufacture being merely most useless, to-morrow become embraced within the an illustration of it. Substances which to-day are the circle of industrial utilities. It is quite true that there Among the drinks there are also some novelties in the case of Mr. Garton, at present uncatalogued, but just over those we have mentioned. Mr. Garton has taken out a patent for converting common cane sugar into grape sugar, and using this for the production of beer, wines, and spirits. The conversion of the sugar is effected in a very ingenious way. Some ready-made glucose and a little acid are added to the dissolved cane sugar, and the mixture is then strongly agitated for a considerable time, after which it is found that the whole of the sugar has undergone a change from cane sugar to grape sugar. The great difficulty which Mr. Garton had to overcome was that of getting the sugar back properties, or all the uses to which it can be applied for again to a solid form, for our vexatious excise regula- the purposes of common life. I take Boyle's old title as tions forbid the entrance of anything like molasses to a the text for our discourse; but I have only time to give brewery or distillery. The inventor has, however, suc-it a very limited application, by describing the utilities is no one substance in nature of which we know all its now derived from tar, although time will not allow me to completely that we are obliged to add more water in order embrace them all in one lecture. to fill the tube. You will recollect what were the waste products of the coal-gas manufacture. You will find the products of the distillation of coal in the first diagram on the gallery. First, gaseous products were produced, part of which were useful-the diluents and illuminants; part were impurities, and were got rid of by certain processes. Even these impurities are in some cases now applied. After that there was the crude coal oil, which is commonly called tar; and then there was a watery portion which contained salts of ammonia. We, therefore, had the gaseous products, the crude oil or tar, and the watery distillate. All except the gaseous products were regarded as impurities-waste substances which were got rid of, and the getting rid of which was a serious undertaking to the gas manufacturer; and I wish now to show you how all these have been utilised. We begin with the gas water, the badly-smelling, black, ugly gas water of the gas-works, and see what has been obtained from it. The gas water contains salts of ammonia. These salts of ammonia, except in one instance, consist of the base ammonia united with volatile acids, sulphuretted hydrogen, and carbonic acid in the other. A certain quantity of chloride of ammonium, or ammonia in union with hydrochloric acid, is also found in the gas water. The value of these salts of ammonia was long known before they were extracted from the watery waste product of the gas manufacture. In fact, ammonia derives its name from one of the titles given to Jupiter, "Jupiter Ammon," near whose temple in Upper Egypt ammonia was for many generations manufactured from the refuse of camels, which was taken and heated and distilled, and gave off ammonia or some of its salts. Hence its name. Its uses were familiar in this country, and its applications to manufactures were known long before persons thought of extracting it from gas water. After a time chemists found sulphide of ammonium and carbonate of ammonia in the watery portion of the coal gas distillate. This distillate gives a very abundant source of ammoniacal salts, and, in fact, the source from which it is now almost all derived. As, however, the subject of to-day's lecture, when we come to the colours produced from coal-tar, wholly relates to the characters of ammonia and the base which is in these salts, I must be permitted, with the excuse of the many chemists whom I see present, to tell those who are not necessarily chemists what ammonia is, and what are its peculiar characters. The general character of ammonia is probably known to you all. Here is a vessel containing it. It is, as you will see, a colourless gas. It has a very pungent smell; it has an alkaline character; and it is extremely soluble in water. Mr. McIvor will now agitate a portion of this with water, and then you will see how soluble it is. Its alkaline character I wish to explain to you for a moment. An alkaline character is the character possessed by certain bases, such as soda and potash, and a trivial feature of it, but a very important one, is that it renders reddened infusions blue. I have got here the alkali soda, and if I add it to a reddened vegetable infusion, you see the reddened vegetable infusion becomes blue. This is an ordinary character, and apparently a trivial matter, but still an important one. Now we will agitate this ammonia with water, in which it is partly soluble, and we will admit the water into it, and you will see how it rises. You will observe, at the same time, that this red matter as it rises becomes blue. It is so exceedingly soluble in water, that the water dissolves the ammoniacal gas; and its alkaline character is shown to you very distinctly by the red colour of this red water becoming strongly blue just as this fixed alkali soda or potash rendered it blue. Observe how extremely soluble this alkaline ammonia is. You see the water absorbs it so It is the character of an alkali to unite with an acid. An acid with which it forms, one of the most economical salts of which I have to speak, is muriatic acid. Here I have some muriatic acid-colourless, like the ammonia, but yet possessing very different properties. You see in this case we have got this water blue instead of red, and we will now remove our vessel and agitate it in the same way. We introduce a little of the water and shake it up, so as to dissolve some of the muriatic acid, which is of a different character altogether from ammonia. And now we pass it back into the basin of water coloured blue. The other was red and became blue; but now the blue becomes red, from this gas being an acid-having an acid instead of an alkaline character. Now, I wish to show the effect when these two gases are mixed. We must allow a little time for the completion of the experiment. I have here some ammonia, and I will place a flame below it; and in the other retort I have an acid, and I will place a light below that also. This is When both of these are heated we will muriatic acid. bring the vapours into contact. You will see then that the muriatic acid will unite with the ammonia, and produce a substance which is exactly the same, although not in such a solid form, as this muriate of ammonia [referring to a large white block of that substance on the lecture table]. It is hydrochloric acid and ammonia which form this solid cake in the manner in which it occurs in commerce. How completely, you will see, this shows the deductive character of chemistry. Chemistry, in its present state, is not an inductive science; it is a deductive science. It is a science taught to us by experiment. These liquids are now nearly boiling, and we will pass the two gases into this large tube. [The vapours of the ammonia and the hydrochloric acid were passed through separate tubes up into a large glass globe, and there allowed to mix]. They are now joining one another, and they are forming this solid white muriate of ammonia by their union. You see how this solid body is formed from two gases, a result which could not have been predicated by any science, and is only taught to us by experience. Having explained the preliminary points to you, I now desire to show how salts of ammonia are manufactured in the arts. When a ton of coal is distilled, above ten gallons of the watery portion comes over from it-ten gallons from Newcastle coal. This contains sulphide of ammonium and carbonate of ammonia. Now, sulphuretted hydrogen and carbonic acid are both volatile substances. It is, therefore, only necessary to add a strong acid to obtain whatever salt we please from these compounds of ammonia. Muriate of ammonia is manufactured in this way:-The gas liquor is run into a deep cistern. This cistern is connected with a chimney, and there is poured into it muriatic acid. That muriatic or hydrochloric acid expels the sulphuretted hydrogen and the carbonic acid, and forms muriate of ammonia in solution. The bad-smelling gas, sulphuretted hydrogen, which smells like rotten eggs, is passed up the chimney, and removed from the locality of the works, to be given to people living at a distance. The muriate of ammonia is placed in a pan containing about 1500 gallons, and evaporated till strong enough to crystallise. The muriate of ammonia obtained in this way is impure, and has to be sublimed in order to be obtained in this state. This is a piece taken from the top of the retort. After that it is removed to a still of this kind-an iron pot surrounded by a leaden dome; and here a fire is placed below it, and the muriate of ammonia vaporises from its impurities, and condenses at the top as a crystalline solid. About 4000 tons of this muriate of ammonia are made annually in this country from gas water. It is used extensively in making alum, |