child had been taking one-fifth of a grain of | sugar of lead two or three times a-day, for nearly nine weeks. About this time it got worse, and Dr. G. A. Rees was sent for. This gentleman instantly recognised the symptoms of poisoning by lead, and, after searching into its source, he traced it to the medicine, and advised its discontinuance. Two days after this the child died, and, at the instance of the coroner, we were called upon to make a further inquiry into the case. It was learned from the parents, that the child was a fine healthy boy before this sickness, but that, almost immediately after it had commenced taking the schoolmaster's medicine it began to fall away, and to complain of severe pains in its belly; these were proved to be of a colicy nature, by the fact, that the child always lay upon its abdomen when it sought relief or went to sleep; its belly also became hard, and rather pinched in; the bowels were very confined, and the stools black and disagreeable, there was also a most intolerable foetor of the breath; latterly the child got very drowsy, and was unable to move about as usual; in short, the limbs were beginning to get palsied. Upon the day of its death, however, it became convulsed, and a few hours before death, fell into a state of coma, from which it was never roused, RISING OF LAND.* It is a fact, worthy perhaps of a passing notice, that the whole of the land in and about the neighbourhood of Conception Bay, Newfoundland very probably the whole island is rising out of the ocean, at a rate which promises, at no very distant day, materially to affect, if not render useless, many of the best harbours we have now on the coast. At Port-de-Grave a series of observations has been made, which undeniably prove the rapid displacement of the sea level in that vicinity. Several large flat rocks, over which schooners might pass some thirty or forty years ago with the greatest facility, are now approaching the surface, the water being scarcely navigable for a skiff, At a place called the Cosh, at the head of Bay Roberts, upwards of a mile from the sea shore, and at several feet above the level, covered with five or six feet of vegetable mould there is a perfect beach-the stones being of a moderate size, and in all respects similar to those now found in the adjacent land-washes. *Newfoundland Times. INDIAN COBALT. A NEW field of cobalt has been discovered in the East Indies, in the mountainous country of Rajpootanah-a district already celebrated for its mineral wealth, and principally for its rich and various copper ores and its alums. It is in one of the copper-mines. that this cobalt is found-lying abundantly in the state of sulphate of great purity. It is accompanied by only one other sub.. stance-pyrites of iron, highly magnetic, and easily separated from it by a loadstone of moderate power. These it contains in the proportion of 9-22 per cent. The remainder of the mineral consists wholly of pyrites of cobalt, of the specific weight of 5.45 and the composition following:-cobalt 64.64, sulphur 35 36. The Indian jewellers already use it advantageously for colouring gold, with a rose tint of great delicacy. NEW CEMENT FOR THE TEETH. M. OSTERMAYER proposes a cement which he considers to approach very nearly to the composition of enamel : it consists of quicklime, 13 parts; anhydrous phosphoric acid, 12 parts. The lime must be finely pulvesized, and chemically pure, The anhydrous phosphoric acid is obtained by the combustion of phosphorus in dry air. The two substances are to be quickly mixed together, so as to form a powder. This is to be introduced into the cavity of the tooth, previously dried, and to be moistened with a small quantity of water. THE CHEMIST. 1. CHEMISTRY. EXPERIMENTS ON THE COMBINATIONS OF MELLON.* BY MESSRS. M. M. A. LAURENT AND CH. GERHARDT. In consequence of the animadversions of M. Liebig on the chemical researches of Messrs. Laurent and Gerhardt, the latter chemists undertook the following experiments, the result of which they laid before the Academy of Sciences. The comparative study of the changes organic substances undergo, by means of chemical agents, suggested to us, lately, several new ideas on the chemical equivalents of these substances, and also on certain relations that exist between the equivalents of the elements of which they are composed. We were thus led to establish the principle, that in a regular and precise notation, corresponding with four volumes of vapour 1. The equivalent of every oxigenated substance, gave an even number, for the exygen and its substitutes-sulphur, selenium and tellurium. 2. The equivalent of every non-nitrated substance gave a number divisable by four, as the sum of the hydrogen and its substitutes-halogenated substances and metal. 3. The equivalent of every nitrated, phosphorated, or arseniated substance, gave a number, also, divisable by four, as the sum of the hydrogen and nitrogen, or their substitutes. 4. The equivalent of every carbonated substance, always contains an even number of the equivalents of carbon, or is divisable by four, with C-37.5. In a notation corresponding with two volumes, the preceding values are divided by two. On account of the simplicity of the formula, we give the preference to this second mode of notation. Since these propositions were laid down, they have been confirmed by the composition of all well studied bodies; there were * Comptes Rendus, March 16, 1846. N.S., VOL. IV.-No. XLI., May, 1846. but a small number of substances, and those ill understood, and badly analysed, the composition of which did not agree with these views; many exceptions of this kind have also disappeared, since the analyses of several of the substances have been carefully repeated. Up to the present time, we have been alone in supporting our opinion, not that it has been attacked by means of experiments. We confidently say, no chemist has, as yet, established a single well-proved fact, contrary to the preceding propositions. We now ask for the judgment of the Academy. The new experiments we are about to lay before it will enable it to decide between M. Liebig and ourselves. The question in dispute between us reduces itself to the following points :-Either our four propositions are untrue, or M. Liebig's experiments on mellon, sulphocyanogen, and their derivatives, are false. It must be observed that M. Liebig's experiments on mellon and sulphocyanogen, form one of the principal supports of the theory of compound radicals, taught by that chemist at Giessen. The history of mellon is noticed in M. Gay-Lussac's celebrated work on cyanogen; like that gas, mellon, according to M. Liebig, is a radical composed of carbon and nitrogen, the mellonides correspond with the cyanides, and hydromellonic acid with hydrocyanic acid. It is the same with the radical, sulphocyanogen. At the time we made our last communication we had not repeated all the experiments of M. Liebig. We had only modified a part of the theory, and the authority M. Liebig's name bore, appeared sufficiently to warrant the correctness of the other results. But now we regret that we must inform the Academy, that this confidence has entirely deceived us, it is not only a portion of M. Liebig's researches that is false, but the whole history of mellon and sulphocyanogen, all their transformations, and all their reactions. More than this, we are enabled to prove that the pretended analogues of cyanogenmellon and sulphocyanogen-do not exist. 2 B Thus the base of his theories falls to pieces, theories that for ten years have exercised the most baneful influence on science, by induc, ing a majority of chemists to seek these imaginary compounds. MELLON. constitutes mellon. The same product is also formed by the chlorocyanamide to be a combination of cyanamide, an imaginary body, and protochloride of cyanogen, another imaginary body. These hypotheses necessarily fail in the face of the composition we have just given. When we heat chlorocyanamide, according to M. Liebig, it sublimes a white substance, In the dry distillation of the yellow sub-containing the whole of the chlorine and stance, called, improperly, sulphocyanogen, chlorocyanamide, and the mellon remains. we obtain a grayish-yellow residuum, which If the reaction takes place, as M. Liebig says it does, the formula we attribute to mellon, is evidently incorrect. We have rewith surprise that the chlorocyanamide is peated this experiment, and we have seen transformed, not only into mellon and sal ammoniac, but that an enormous quantity of hydrochloric acid is also disengaged; about 16 per cent, or one equivalent. action of heat on melam, ammeline, amme lid, chlorocyanamide, and persulphohydrocyanic acid. When we employ sulphuretted bodies to prepare the mellon, it is difficult to obtain it perfectly pure; but, it is not the same when we prepare it by calcining chlorocyanamide and ammelid. Our analyses, made upon the products obtained by these processes, gave us, exactly, the formula C6 H3 No. M. Liebig does not admit the presence of hydrogen in this compound; he only discovered eight atoms of nitrogen, instead of nine; and he also supposed that, under the influence of heat, mellon was transformed, purely, and simply, into three volumes of cyanogen, and one volume of nitrogen. In this there is a serious error, to which we shall recur presently. Let us now see whether the composition we assign to mellon agrees with that of the bodies from which it is derived, and with its transformations. FORMATION OF MELLON BY CHLOROCYANA If we deduct from the elements of the chlorocyanamide, the elements of one equivalent of sal ammoniac, and one equivalent of hydrochloric acid, the remainder exactly represents the composition we have attributed to mellon; the following equations show the formation and decomposition of chlorocyanamide : CHL. SOL. OF CYAN. 2 C3 N3 C13+ H3N C6 H8 N10 C12+ 4 CH. FORMATION OF MELLON BY AMMELID. According to M. Liebig, ammelid should have for its formula C6 H9 N9 03. This composition not agreeing with our views, one of us thought, more than two years since, it ought to be replaced by the following :-C3 H4 N4 O2. This correction was afterwards justified in a very remarkable manner, it was admitted by M. Liebig himself, without any doubt on his part. M. Liebig, in fact, has just published, in concert with M. Wöhler, the announcement of a new derivative of urea, to which he assigns precisely the formula we have proposed for ammelid. These properties, and the composition of this new body immediately struck us, since they appeared to be applicable to a body already known-ammelid. We therefore repeated the experiments of the German chemists, and we can affirm that the pretended new body of Messrs. Wöhler and Liebig, is no other than ammelid.* We * By the side of the announcement of this new body, is found another, in the same number, of a new cyanic ether; but the formation, the properties, and composition of this new body, evidently proves that this pretended new ether is only the urethane of have analysed it, as well as the ammelidate of silver, and our experiments have led us to the following formula :-C3 H4 N4 O2. We have seen that, by calcining ammelid, cyanuric acid, cyanic acid, and ammonia, were disengaged; while mellon remained: there remains the elements of one equivalent of mellon which agrees with the formula, we attribute to it 6 (C3 H1 NO2) = 3 (C3 N3 H3 O3+CHNO + H3 N) + C6 No H3. FORMATION OF MELLON BY POLIENE. The result of M. Voelkel's experiments is, that the melam of M. Liebig is an impure substance, as one of us had already announced, and is composed of a mixture of melam and a substance isomerous with melamine and poliene containing C3 H6 N6. Melam has not, therefore, the composition attributed to it by M. Liebig. Again, poliene, subjected to the action of heat, disengages ammonia, and leaves mellon: this decomposition, therefore, again confirms the formula we give to mellon 2 C3 H6 N6=C6 H3 N9 +3 H3 N. FORMATION OF MELLON BY PERSULPHO HYDROCYANIC ACID. According to M. Liebig, persulphohydrocyanic acid, subjected to the action of heat, is completely decomposed into sulphuret of carbon, sulphuretted hydrogen, sulphur, and a residuum of mellon, from which potash extracts, without the aid of heat, hydromellonic acid, while with heat, it yields mellonate of potassium, or a new salt, containing no hydrogen. one of us, after the indications of M. Liebig for hydromellonic acid. If we have committed an error, it must be entirely attributed to the numerous contradictions and mistakes to be found in M. Liebig's memoir on this subject. We will return to these compound bodies in another memoir. Finally, the residuum of the calcination of persulphohydrocyanic acid, or mellon, gives no trace of hydromellonic acid, when treated with potash. The preparation of mellon, by the calcination of persulphohydrocyanic acid, is easily understood, for it is preceded by that of poliene, and it is the latter which is converted, as we have seen, into mellon and ammonia. THE ACTION OF HEAT ON MELLON. M. Liebig has said, and repeated it many times, that mellon is decomposed by the action of heat, into three volumes of cyanogen and one of nitrogen. If mellon has the composition we attribute to it, such a decomposition is impossible. We have repeated M. Liebig's experiments, with pure mellon, arising from the chlorocyanamide, and we have seen, that, besides the cyanogen and nitrogen, whose proportions vary considerably, at the beginning and at the close of the operation, a gas is disengaged absorbable by hydrochloric acid, while two different substances are sublimed, one of a reddish colour and the other yellow. We could scarcely comprehend, how a decomposition so complicated only exhibited, in the hands of M. Liebig, three volumes of cyanogen and one volume of nitrogen; but his theory required it to be so. ACTION OF POTASH ON MELLON. We completely disagree with M. Liebig. By the calcination of persulphohydrocyanic acid, sulphuretted hydrogen, sulphohydrocyanic acid, bydrosulphate of ammonia, sulphur, yellow crystals, Zeize salt, and an enormous quantity of ammonia, whose presence entirely escaped the attention of M. M. Liebig, when examining the action of Liebig, are disengaged. In addition to this, potash or mellon, perceived that a new salt the matter dissolved in the potash, without was formed, to which he attributed the folheat, is not hydromellonic acid, but a mix-lowing composition :-C4 N5 Ag2 O, salt of ture of sulphur and ammelid. It is the gelatinous appearance of the precipitate that led M. Liebig into error. silver. Our experiments on this subject being not yet concluded, we shall, at present, confine Finally, boiling potash does not convert ourselves to saying, that the formula of this the residue into mellonide and a new salt, salt is entirely different, and that it is imposfree from hydrogen. This new salt is tri-sible that such a body should be produced basic; it contains hydrogen, and its acid is of exactly the same composition as that we have attributed to hydromellonic acid in our last communication. It is that assumed by M. Dumas. We propose to publish a note upon this subject, as soon as we learn that M. Wurtz acknowledges the identity of the two substances. under the influence of potash, if the formula of mellon is such as we have attributed to it. We will return to this compound in another memoir. ACTION OF POTASSIUM ON MELLON. M. Liebig's theory appeared to be solidly based, by the fact of the direct combination of his mellon with metallic potassium, but his theory prevented M. Liebig seeing correctly. If we take very pure mellon, arising from the calcination of chlorocyanamide, heat it with a morsel of potassium cut round with a penknife, so as to have it free from naphtha, the combination will be immediately effected, with the disengagement of light, but, at the same time, a large amount of ammonia will be also disengaged. This disengagement of ammonia did not entirely escape M. Liebig's notice: but he attributed it-who would have thought it?to the naphtha adhering to the potassium We will return, in another memoir, to the composition of the mellonurets. We know that M. Liebig considers the latter as a simple compound of cyanogen and sulphur, his theories required this. But the correctness of M. Liebig's analysis had been already contested by Messrs. Parnell and Voelkel, who assert that sulphocyanogen contains in addition, oxygen, and more than a hundreth part of hydrogen. The formula proposed by Messrs. Liebig, Voelkel, and Parnell, appeared to us inadmissible, and we have studied the subject anew. After having passed a current of chlorine through sulphocyanuret of potassium, we examined the yellow precipitate with a microscope; but what was our astonishment at seeing that this precipitate was a mixture of three different substances, and yet it is on such a mixture that M. Liebig has founded the theories of sulphocyanurets. To obtain pure sulphocyanogen, we had to pass a current of chlorine through sulphocyanuret of potassium. We stopped the operation from time to time and filtered; then we examined with the microscope, successively, all the precipitates, and we analysed that which appeared to us to be most homogeneous. Here is another fact which we hand over to chemists for their appreciation. When we add an acid to a mellonuret, it produces a white precipitate, which M. Liebig described at length, some time since, under the name of hydromellonic acid. One of us, while operating on this product, perceived that it contained large quantities of potash, and we acquainted M.Hoffinan, M. Liebig's nephew, with the fact; we know not whether this letter was communicated to M. Liebig, we are willing to believe that the communication was never made to him; but since we pointed out the presence of potash in hydromellonic acid, M. Liebig suddenly changed his opinion. The companion to hydrocyanic acid, hydromellonic acid, no longer exists, according to him; the body he analysed and described under that name, is now only an acid mellonuret of potash leaving, by calcination, 17 per cent. of the cyanide of that metal.* 3CNSH+C12 C3 N3 S3 H+ 2 H Cl. M. Liebig relies on this fact to accuse us of As to the formation of mellon by the calbad faith, by pretending we never made the cination of the so called radical, of the sulexperiments, we communicated to the Aca-phocyanurets, it is easily understood. We demy. The substance, after having been long and well dried, was quickly weighed to give it no opportunity of absorbing moisture, we obtained by analysis, results which are well represented by the following formula :C3 N3 S3 H. We have, therefore, along with the sulphohydrocyanic acid H know that in this operation sulphur or sulphuret of carbon-are disengaged while mellon remains, we have therefore. 3C3 N3 S3 HC6 H3 N2 + 3CS2 + S3. CONCLUSIONS. To sum up this discussion, we should say— 1. Mellon is not as M. Liebig says, a binary compound, that may be compared with which do not exist in the proportions mencyanogen; for besides the carbon and nitrogen, tioned by M. Liebig, it contains a half per cent. of hydrogen and is represented by C6 H3 No. 2. Mellon does not combine purely and simply, as M. Liebig says, but the combination is accompanied by the disengagement of ammonia, and the product forms a bibasic salt C N8 M2; a salt, which, when dissolved in water gives, perhaps, C6 N8 M2 H2O. 3. Mellon arising from the calcination of per sulphohydrocyanic acid, when dissolved in potash, does not yield a mellonuret as M. Liebig has advanced, but produces a tribasic |