NEWS SCIENTIFIC AND ANALYTICAL CHEMISTRY. Analysis of the" Montpellier Saline Chalybeate" Water, Harrogate, by Dr. SHERIDAN MUSPRATT, M.D. (Hon,) F.R.S. Ed., M.R.I.A., &c. HAVING, at the suggestion of numerous scientific men, undertaken an analysis (just completed) of the above famous spring, which is often called, in Harrogate, Kissingen Water," although its constituents bear very little resemblance to the world-renowned Continental spa; and as Dr. Kennion, the eminent consulting physician, regards my results "most interesting as a safe guide in prescribing," I am induced to forward these few remarks, with the tabular analysis (mean of four determinations) for publication in your ably-conducted scientific journal :— On the Amines of Benzoic Alcohol,* by M. CANNIZZARO. For the same reason that phenols were long supposed to be analogous to alcohols, it has until lately been thought that aniline, toluidine, and their homologues were alkaloids of a constitution analogous to that of methylamine, ethylamine, etc. The discovery of benzoic alcohol, and the comparison of its properties with those of cresylic phenol, has controverted the first of these opinions. The facts which I have the honour of submitting to the Academy show that the alkaloid derived from benzoic alcohol, the true primary benzylamine, differs altogether from toluidine, whence it may by analogy be inferred that alkaloids derived from true aromatic alcohols differ from those which are analogous to aniline. The following is the method for obtaining primary benzylamine:--Mix chloride of benzyl (benzhydrochloric ether) with an alcoholic solution of ammonia, and leave the whole to stand for a few days. White * Comptes Rendus, lx., 1207. VOL, XII. No. 295.—JULY 28, 1865, crystals then form in needles and flakes, which separate from the liquid. These crystals are merely the tertiary benzylamine which I described some years ago. and treat the residue with hot water. There remains Filter the liquid, distil the alcohol in a water bath, an insoluble matter which fuses in hot water. This is a second and slightly coloured portion of tertiary benzylamine. Evaporate the partially-cooled aqueous solution, separated by filtration from the latter substance, to dryness in a water bath. A saline residue remains, which is a mixture of a little sal-ammoniac and the hydrochlorates of primary benzylamine and of another alkaloid, probably secondary benzylamine. Separate, by fractional crystallisation, the portion which is most soluble in water, which is nearly pure hydrochlorate of primary benzylamine. A free alkaloid is obtained by treating a concentrated aqueous solution of this hydrochlorate by an excess of potash solution. The alkaloid then floats on the surface. To assist the separation add ether; separate the etherial from the aqueous solution, and distil the ether in a water bath. Place the residue, slightly coloured yellow, in contact with a stick of fused potash to dry it and to preserve it from the action of the carbonic acid. After a few days separate the limpid liquid from the potash and distil, collecting what comes over at about 182. Colourless primary benzylamine is thus obtained. This is not, however, perfectly pure; when mixed with water it gives a turbid solution, caused apparently by the presence of a little secondary alkaloid." By repeated fractional distilllations benzylamine is at last with difficulty perfectly purified. I, however, effected this object by the following method :-I passed a current of dry carbonic acid over primary benzylsolid compound formed and the temperature rose. I amine purified as much as possible by distillations; a washed this compound with perfectly dry ether, which which did not absorb carbonic acid and remained liquid. took away the small quantity of the other alkaloid, This solid carbonate, dried on blotting-paper, I dissolved in hydrochloric acid, carbonic acid was disengaged; I crystallised the hydrochlorate formed and then extracted the alkaloid by the process above described. The alkaloid C,H,H2N thus separated is a colourless liquid, boiling without decomposition between 182° and 183 (uncorrected). It seems unalterable by the action of the sun; it mixes with water in all proportions; potash in excess separates it from these solutions, tinging it with yellow; it rapidly absorbs carbonic acid, giving a crystallised compound as does amylamine. It has an energetic alkaline reaction, fumes when in contact with hydrochloric acid, combines with acids with considerable disengagement of heat, and gives neutral salts. The hydrochlorate C,H,MHCI crystallises in striated flakes; with platinic chloride it gives a chloro. platinate crystallised in orange coloured plates. These characteristics sufficiently show how much this alkaloid differs from toluidine. The difference consists not only in the physical characteristics and solubility in water, but also in the chemical properties. Toluidine is a very feeble alkaloid, while the basic characteristics of benzylamine are as pronounced as those of ethylamine and its homologues. Starting upon the supposition that benzylamine is to toluidine what benzoic alcohol is to cresylic phenol, I have endeavoured to find out whether, by making the radical benzyl take the place in toluidine of the two other atoms of hydrogen which remained of the am monia a body would be obtained isomeric or identical with tertiary benzylamine. The result will be communicated in a succeeding paper. PHARMACY, TOXICOLOGY, &c. On the Ointment of the Yellow Amorphous Oxide of Mercury, by Drs. HOFMANN and PAGENSTECHER. WE borrow the following from the pages of our valuable contemporary, the Ophthalmic Review - Two forms of oxide of mercury are recognised?— 1st. The crystalline or red oxide, prepared by the dry method, and commonly known as red precipitate, constituting the very common remedy; and 2nd. The amorphous, or yellow oxide, prepared by the wet method, by precipitation; up to within a few years unknown to the Pharmacopoeia, although it is indubitably preferable to the first. The common red precipitate is rendered applicable to practice by being triturated in a porcelain mortar till no more brilliant crystalline points can be perceived; a powder is thus obtained which is quite soft, and when rubbed between the fingers no longer imparts any gritty feel. If this, after being prepared in the most careful possible way, is submitted to the microscope, it may, under a magnifying power of even 120 diameters, be recognised as a mass of broken crystals. The point up to which the trituration should be continued, which forms the measure of the fineness of the division, is in this method uncertain and inconstant. Thus this preparation occurs in different degrees of fineness in different shops; and as its efficacy is intimately connected with its fineness, the surgeon gets preparations which act with unequal strength. For obtaining, therefore, a preparation uniform in its effects, and in the finest possible state of division, the yellow precipitate, which is thrown down, is highly to be recommended. Thinking this would also prove a far more energetic preparation, I, in 1856, for the first time prepared some, and recommended its use to Dr. Pagenstecher in his eye practice, instead of the common precipitate, and found my anticipations most gratifyingly confirmed. The mode of preparing the yellow precipitate, although well known, may be still worth mentioning. Care must be taken in the precipitation to obtain a pure oxide, and not any of its compounds, to which precipitates of mercury have a great tendency-a fact which might detract from the efficacy of the preparation. The precipitation is effected by adding a solution of the chloride of mercury to a solution of potash, in such a way that there is always an excess of the latter. After the precipitate has deposited itself, the supernatant fluid is at once poured off, the precipitate thoroughly washed with distilled water, and dried by a gentle heat, with exclusion of daylight. Thus prepared, the yellow prccipitate has a light yellow (that of the yolk of an egg) colour, and is an exceedingly fine powder, which, even under the microscope, appears completely amorphous. In addition to both the above signalised properties, it differs from the ordinary precipitate in its chemical behaviour, being much more quickly acted on by reagents. A solution of oxalic acid, which acts on the red oxide only after boiling, very quickly changes the yellow oxide, even at the ordinary temperature, into the white oxalate. The preparation of hypochloric acid gas depends on the property the yellow oxide of mercury possesses of decomposing in contact with chlorine gas; the results being NEWS hypochloric acid and chloride of mercury; whereas the red oxide undergoes, with chlorine gas at the ordinary temperature, hardly any change. This difference of chemical behaviour of the two oxides constitutes a diffe rent degree of resistance to the various agents they are submitted to, and is explained by their different states of cohesion. In respect to the use of the yellow precipitate for eye ointments, I may be allowed to say a few words on the vehicle of the ointment. The most perfect vehicle for an eye ointment must be very soft, without, however, being too fluid, lest the heavy oxide sink to the bottom; but when in contact with a moderate heat of the body, it must completely melt, so that the preparation it contains may become quickly and uniformly diffused over the eye. Besides this peculiarity of consistence, the vehicle must be as far as possible indifferent in its behaviour to the oxide, and exhibit the least possible tendency to rancidity, which might exert a deoxidising, reducing action on the oxide. Numerous experiments with hog's lard, butter, glycerine, glycerine ointment, and mixed fats, have led me to give preference to the last, and I recommend either the mixture of spermaceti, wax, almond oil, and rose-water, known as cold cream, only omitting the water, as this favours rancidity, and substituting for it quantities of almond oil, varying according to the heat of the weather; or a mixture of coca-butter and almond oil, likewise proportionate to the temperature. In both compounds the almond oil must be as fresh as possible, and had best be prepared by the apothecary himself. As regards the strength of the ointment, I generally use one drachm of oxide to one ounce of fat. This may appear very strong to some, but experience amply shows that, applied in proper cases, it does not in any way irritate too much. Idiosyncrasies may, of course, be observed, as in every remedy; and if the ointment in a given case irritates too much, its strength may be reduced to thirty grains of oxide to the ounce. I may further remark, the two constituents of the ointment must be rubbed up to a most intimate admixture if it is to act well. The following are, then, the two formula:R. Hydrarg. oxydat. flavi, gr. xxx. (Via humida parati.) Ung. cetacei, 3ss. Misce exactissime et fiat unguent. R. Hydrarg. oxydat. flavi, gr. xxx. (Via humida parati.) Ung. cetacei, 3j. Misce exactissime et fiat unguent. THE DUBLIN INTERNATIONAL EXHIBITION. By CHAS. R. C. TICHBORNE, F.C.S., F.R. G.S.I., &c. (Specially Reported for the CHEMICAL NEWS.) (Continued from page 29.) The Colonies.-Canada sends a magnificent collection of minerals, forwarded from the Crown lands and by the Board of Arts of Canada, Montreal. Amongst them are fine specimens of plumbago, carboniferous pyrites, nickel ores, splendid crystals of amethyst quartz, a Canadian apatite of importance, as it can be procured in large quantities, and contains 90 (80?) per cent. of phosphate of lime. This mineral is exhibited by Messrs. Rickman, of Liverpool. The Falkland Islands send specimens of oil, crude and refined, from the king penguin. This is an oil something intermediate between cod oil and seal oil in its properties. From the Indian museum a very interesting collection of mineral, agricultural, and manufacturing products, including materia medica, are exhibited; also a very fine collection of raw products exhibited by Mr. Baden Powell, from the Lahore Central Museum. The Newfoundlanders are evidently trying to find applications for the fish caught in connection with the cod oil fisheries. De Grouchy and Co. show an assortment of preserved fish, and amongst others a noveltyviz., "cod tongues preserved." W. Mort, 155, Fenchurchstreet, London, exhibits a stupendous block of malachite from the Peak Downs Copper Mines. Such a splendid specimen as this is really a treat to mineralogists. Victoria has contributed largely. The Bank of Australasia sends a collection of gold selected and prepared by the bullion clerk and the bank assayer, Mr. Paterson. The total value of the gold exhibited in its different states is 33597. 8s. 9d. We have also 29257.'s worth from the Union Bank of Australia. This is a very interesting collection, as we have specimens of all the alluvial gold of Australia and New Zealand. It is said that the gross weight of gold which has been produced from the mines of Victoria in little more than thirteen years is over 1024 tons, the value of which is 133,861,7087. sterling. The mines of Victoria are now in a more prosperous condition than they have been for some years past. In this section there are a number of essential oils new to British commerce. The oil of peppermint has the same character as the English oil, and is distilled from English peppermint grown in the colony. It is sold at 40s. per pound. The oil of Eucalyptus Amygdaline can be produced wholesale at 38. per pound; 1 cwt. of leaves and twigs yields 22 oz. oil. This oil is now being supplied to the London market. The gum of this tree is soluble in water, and possesses valuable tanning properties. Quantities could be shipped. Ceylon.-Simmonds, P. L., roccella tinctoria Nigella sativa, cassia bark, cinnamon, Juffna moss (Plocarix Candida), nutmeg fruit. Professor A., collection of medicinal plants. These are very interesting, and are accompanied by a description. Brousse, vanilla. Mauritius.-Bonton, Langlos, mace and nutmegs, &c., in their natural state Scott, column of coal from Albion Mines. Thirty-six feet six inches represents the thickness of the main seam. Wamerly German Gold Mining Company, bar of gold 48 lbs., and auriferous quartz. Queensland.—Simmonds, Dungong oil (a substitute for cod-liver oil), Australian manna. Vancouver's Island.-Simmonds, Ostoocham oil (a fish oil recommended in place of cod-liver oil). Victoria.-Connor, resins, &c. Beveridge, resin of callitris verrucosa. Hood and Co., collection of chemicals and soaps. The latter at very low prices. Hobson's Bay Soap and Candle Company. Müller, Dr., F.R.S., a fine collection of gums. Foreign States-The house of Petricoli, Austria, a very ancient firm, shows in Section 2 some beautifully bleached wax, and state that it is bleached naturally, and that chemically bleached wax is always tinged, and, therefore, requires the admixture of stearine or spermacetic to make it presentable. How far this is the fact has to be proved, but the wax exhibited possesses a virgin hue which the writer has never seen equalled. In the Belgium Department there are two exhibitors of oxide of iron, which, under the name of minium de fer, is extensively used as a paint for metal work. That of MM. Hoorichx and Gorrissen, Brussels, consists of burnt ochre, and is offered at a remarkably low price -about 5s. 6d. per cwt. The article exhibited by Eucalyptus Corymbosa yields an oil the wholesale De Cartier, Brussels, costs about 16s., and is quite a price of which is 6s. per pound, as 1 cwt. of leaves and different product; it is got by burning and powdering twigs will only give 9 oz. of oil. The oil of Melaleuca hematite, and levigating it with water. It is called Ericifolia can be manufactured for 20s. per pound, 1 cwt.minium de fer d'Anderghem, and is being manufactured of leaves and branchlets yielding 4 oz. of oil. It is said in immense quantities. M. Cartier says that it is destined that it is equal in effect to the oil from Melaleuca Leuca- to supplant red lead and other paints for iron work; dendron (cajeput oil). It would be interesting to see if colisthar, which by its mode of production always conthis oil consists of the dihydrate of cajeputene of tains some sulphuric acid, a small quantity, it is true, Schmidt-essential oil of Cortex Atherosperma Mos- but enough to attack the iron and cut into it; whilst chata. The physiological effects of this oil in small doses from statements made by eminent English and French are described as diaphoretic, diuretic, and sedative, and chemists the use of red lead is injurious to the iron it appears to exert a specific lowering influence upon the heart's action. "As a medicine it has been used in the Colonial Hospitals, and employed successfully in cases of heart disease. Administered in one or two drop doses at intervals." The leaves give an oil the physiological effect of which is weak in comparison. Fine specimens of the Xanthorrca Australis or Grass Tree Resin are shown. The solution of this gum in spirit leaves a bright red polish on wood. It contains cinnamic and benzoic acids, the action of nitric acid upon the gum gives rise to picric acid. The report also says that this gum will possibly be found useful for dyeing scarlet. Mr. Slater in this section also exhibits some damask roses, which are really fine commercial specimens, proving the desirability of further trying what the climate will do, as regards the cultivation of perfumery plants. Other exhibitors in the Colonial Department see and 2. Canada-Bogart, D. Gospel, petroleum oil. coated with it.* PROCEEDINGS OF SOCIETIES. COLLEGE OF PHYSICIANS. LECTURE I. (Continued from page 32.) You will observe that all I have hitherto said with regard to these three hydrides is simply a matter of experiment or observation, uncontrolled by any theory whatever. It is a matter of fact that if you take equal. volumes of hydrochloric acid, steam, and ammonia gases, you can extract from the ammonia three times as much hydrogen, and from the steam twice as much hydrogen, as can be got from the hydrochloric acid; whereas the amount. In the British Department there are some colours exhibited under the name of "Pulford's Magnetic Paints." This can be understood as regards the brown. The blues and greens proved to be ordinary colours, containing a small quantity of magnetic oxide of iron. of nitrogen you can extract from the ammonia is exactly equal in bulk to the amount of oxygen you can extract from the steam, and to the amount of chlorine, and, consequently, of hydrogen, you can extract from the hydrochloric acid. It is also a matter of fact that if you take equal volumes of hydrogen, chlorine, oxygen, and nitrogen, the weight of these equal volumes will be in the proportion of 1: 35.5 16: : 14, as shown more fully in the table before you. Gaseous Elements and Types. 8.5 8 H2N 17 H.C 16 Now we come to a matter of interpretation. From these, in addition to many other considerations, we accord to hydrogen, chlorine, oxygen, and nitrogen the atomic weights 1, 35'5, 16, and 14, and we express the comparable molecules of hydrochloric acid, water, and ammonia by the formulæ HCl, H2O, and H2N respectively, each of which represents the same gaseous bulk, or 2 volumes of its particular compound. This formula for water is warranted by a host of considerations. It may suffice here to remark that in composition, condensation, and properties, water H2O, is strictly intermediate between the acid monhydride of chlorine HCl, and the alkaline trihydride of nitrogen H,N. Now, what is true of hydrochloric acid is also true of hydrofluoric acid, hydrobromic acid, and hydriodic acid. From two volumes of each of these gases we are able to extract the same volume of hydrogen, while from equal bulks of sulphuretted, selenetted, and telluretted hydrogen, we are able to extract twice the volume of hydrogen, and from equal bulks of phosphoretted, arsenetted, and antimonetted hydrogen we are able to extract three times the volume of hydrogen that we can extract from hydrochloric acid, as indicated in the table. Monhydrides. HCI HBr HI HF Dihydrides. H2O H2S H,Se H2T H&As H3Sb The metals do not, as a rule, combine with hydrogen, but their chlorides may be divided into three classes, corresponding to the chlorides of the non-metals, by having regard to such considerations as the following:We find that the proportions of the solid non-metals, iodine, sulphur, and phosphorus, which unite with one, two, and three volumes of hydrogen respectively, and with one, two, or three volumes of chlorine, as shown cn the above table, and which we have agreed to regard as their atomic proportions, have the same specific heat as one another. Now, if we take for the atomic proportions of the different metals those quantities of the several metals which have the same specific heat as one another and as the atomic proportions of the solid non-metals, then we find that the chlorides of the metals, like those of the non-metals, may be divided into monochlorides, dichlorides, and trichlorides respectively, as shown in this next table. For instance, we have in this table a list of chlorides of metallic and hydrides of non-metallic compounds corresponding with one another. Specific heats of at. weights. Formula. 80 127 6.87 IH Lithium 7 6'58 LCI Sodium 23 675 NaCl Potassium 39 Silver AgCl Now, we find that chlorine is not only capable of uniting with hydrogen in the proportion of volume to volume, but it is also capable of replacing hydrogen in the same ratio in a great variety of compounds. Indeed, we may consider the comparable molecules of free chlorine CICI, and hydrochloric acid HCl, to be derived from the molecule of free hydrogen HH, by a displacement of two atoms, and of one atom, of hydrogen respectively, by equivalent quantities of chlorine. Accordingly we are acquainted with chlorides corresponding to all the pre: considered hydrides, ClCl and CII corresponding to HCl and III, Cl,O and Cl,S corresponding to H,O and H2S, and Cl,N and Cl,P corresponding to H,N and II,P, &c., and these chlorides when in the gascous state are found to have exactly the same bulk as their corresponding hydrides. Thus, from two litres of oxide of chlorine ClO we are able to extract two litres of chlorine and one litre of oxygen, just as from two litres of oxide of hydrogen H,O we are able to extract two litres of hydrogen and one litre of oxygen. Gold Tetrads— Tin. Lead Palladium Platinum Only a few of these metallic chlorides can be vapourised at manageable temperatures; but with regard to such of them as are moderately volatile, it is found that two litres of their respective vapours contain as many litres of chlorine as are indicated by their respective formulæ deduced from the specific heats of their constituent metals. With regard to corrosive sublimate vapour, for instance, we find that from two litres of chloride of mercury Cl2Hg, we can extract two litres of chlorine, just as we can from the same bulk of chloride of oxygen Cl,O; whereas, if we take two litres of chloride of bismuth Cl,Bi, we can extract therefrom three litres of chlorine, just as from two litres of chloride of phosphorus ClaP we can extract three litres of chlorine. We find, then, that in the case of those metallic chlorides which are volatisable we can get from 2 volumes of their respective vapours quantities of chlorine corresponding to the quantities obtainable from similarly formulated non-metallic chlorides. I may take the opportunity of saying that from considerations of this sort, together with others of almost equal cogency, it is demonstrable CHEMICAL NEWS, College of Physicians. that the formula for corrosive sublimate, Cl,Hg, in the old London Pharmacopoeia is right, while that in the British Pharmacopoeia, HgCl, is indisputably wrong. In the present state of knowledge, the matter no longer admits of any question whatever. Having thus considered our primary hydrides of chlorine, oxygen, and nitrogen, as typical of monad, dyad, and triad combinations in general, I now wish to direct your attention, lastly, to their mutual relationship. Here we have them written up in an easy form : Chlorides. HCI KCI Hydrates. H(HO) K(HO) : Amides. H(H2N). K(H,N). If under suitable conditions we act upon hydrochloric acid HCl, water H.HO, and ammonia H.H2N by a metal-say by potassium-we obtain in each instance The one atom of potassium turns the same reaction. out one atom of hydrogen; and from each of the three molecules, instead of chloride, oxide, and nitride of hydrogen, we get the chloride, hydrate, and amide of potassium, which may be regarded as compounds of potassium K, with the residues or radicles chlorine Cl, euryzen HO, and amidogen H,N. Hence, caustic potash and potassamide may be regarded as the hydrated and ammoniated forms of chloride of potassium. In a similar manner to nearly every chloride, mineral or organic, simple or compound, there exists a corresponding hydrate and amide bearing to it the same relation that caustic potash and potassamide bear to chloride of potassium. We may consider chloride of potassium, for instance, as a compound of the metal potassium, with the residue from hydrochloric acid. And in the same way we may consider caustic potash as a compound of the metal with the residue from water, and potassamide as a compound of the metal with the residue from ammonia; and hereafter it will appear that some of the most complicated products of tissue metamorphosis are merely the ammoniated forms of very simple bodies, just as potassamide is the ammoniated form, and caustic potash the hydrated form of chloride of potassium. If in chloride of zinc ZnCl2, we replace the two atoms of chlorine by euryzen or peroxide of hydrogen, we obtain hydrate of zinc; whereas if we replace them by amidogen we obtain zincamide. Similarly if in chloride of phosphorus PCl3, we replace the three atoms of chlorine by peroxide of hydrogen, we obtain phosphorous acid; whereas if we replace them by amidogen we obtain phosphoramide; these three bodies being, so to speak, the phosphorus representatives of hydrochloric acid, water, and ammonia, or of chloride of potassium, caustic potash, and potassamide. Passing on to organic compounds, marsh gas is found to consist of one atom of carbon united with four atoms of hydrogen. Now, if we take the chlorine derivative of this marsh gas-that is, if instead of CH, we take CH,Cl, -and replace the atom of chlorine by an atom of peroxide of hydrogen, we obtain ordinary wood spirit; whereas if we replace it by amidogen we obtain methylamine, a very common product of the putrefactive decomposition of animal matter, as shown in the first line of the next table: Chlorides. Hydrates. CO(HO)2 C2H CIO, CH(HO)O, Amides. CH (H2N) CO(H,N), Again, if in phosgene gas COC, we replace the two atoms of chlorine by peroxide of hydrogen, we obtain carbonic acid; whereas if we replace them by two atoms of amidogen we get urea, as shown in the second line of the table. Physiologists regard urea as a complex organic 41 as the ammoniated form of one of the simplest mineral The next formula, C,H,CISO2, represents chlor-ethyl chloric acid, water, and ammonia. You perceive that this establishment between most complicated and diverse bodies of relations similar to those between chloride of potassium, caustic potash, and potassasubsisting between hydrochloric acid, water, and ammonia— mide-furnishes us with a key to the composition and In bodies with two atoms of chlorine, we may replace metamorphoses of a whole host of organic compounds; but the generalisation is capable of being pushed much farther. either one or both of them by euryzen or by amidogen; or we may replace one of them by amidogen and the other by euryzen; whilst in bodies containing three or four I have here increases in a very rapid manner, according to the well known algebraic rule of combinations. atoms of chlorine, the possible number of derived bodies written down the names of a few well-known double chloro-hydrates, chloro-amides, and amid-hydrates, by way First of all we have difluoride of copper, or cupric difluoride, followed by cupric fluorhydrate; next we come to mercuric dichloride or corrosive sublimate, and then which one of the original chlorine atoms is replaced by to mercuric chloramide, or white precipitate, a body in amidogen. Next we come to cyanuric trichloride and its chloro-diamide, two of the original chlorine atoms are numerous derivatives, in the first of which, namely, cyanuric replaced by amidogen. Then we have in succession cyanuric trihydrate or ordinary pyro-uric acid, cyanuric dihydrateamide or melanuric acid, cyanuric hydrate-diamide or ammeline, and lastly cyanuric triamide or melamine, a body produced, as I have already said, by the action of heat upon urea. I refrain from entering into further details upon this subject. I have shown you the wide applicability of the generalisation, and that by its means we are capable of associating with one another the most diverse bodies, and establishing between them the same simple relations which |