has constantly gained more adherents. The opponent THE CHEMICAL NEWS. of vitalism inferred that in living organisms the same VOL. LXIV., No. 1671. VACUUM SPECTRO.PHOTOGRAPHY.* By Prof. V. SCHUMANN. By means of a new vacuum spectro-photograph which I have personally constructed during the last twelve months, I have found it possible to resolve into separate lines the region of the hydrogen spectrum discovered last year (see CHEMICAL NEWS, vol. lxii., p. 299, Dec. 29, 1890), situate beyond the wave-length 1820, and, in addition, to photograph a more refrangible region which likewise displays a considerable wealth of rays. The number of the lines of the resolved groups is far greater than could be expected from my last year's photograms. For instance, in one of these groups, the length of which does not exceed 11 m.m., I count more than go sharply defined lines. The width of my slit had to be selected not above 0.004 m. m. The success of such delicate proofs depend also on an exceptionally fine texture of the sensitive plate. NOTE ON ESTIMATION OF PHOSPHORIC ACID IN SLAGS. By VINCENT Edwards, F.C.S. HAVING to analyse some samples of slag which contained a considerable quantity of phosphoric acid, and finding they obstinately resisted treatment with aqua regia, it occurred to me that toiling with concentrated sulphuric acid might be effectual. This I carried out in a small flask, such as is used for Kjeldahl's process, adding a globule of mercury at the same time. I took about 0'5 grm. of the substance, which contained much silica and carbon, and boiled till almost white; this took a little over an hour. On cooling I diluted to 250 c.c., filtered off 100 c.c., and precipitated the P2O5 by direct addition of citro-magnesic solution and ammonia; after standing collected the precipitate, dissolved in dilute nitric acid, and estimated by uranium solution, it being impossible to weigh as the precipitate contained a white substance insoluble in nitric acid, most likely silica; this might, however, be removed by evaporation. The process appears satisfactory, and gave 4'5 per cent P2O5 more than by treatment in the usual way with HCl and HNO3. It is quite as simple as by any fusion method, and appears to be a means by which many complex substances which contain phosphoric acid might be dissolved and determined. Lawes' Chemical Works, Barking, November 12, 1891. powers must exclusively prevail as in inorganic nature, seeing that a series of chemical compounds, hitherto known only as the products of vital processes, had now been obtained in the laboratory. Important as this assumption has been and will doubtless remain, it derives little support from synthetic chemistry. For however many products of the anaplastic or -which is less surprising-of the kataplastic metabolism of animals and plants are artificially put together from their elements by all manner of round-about methods, this is merely a fresh proof that these substances may be obtained by another process besides the one which the vegetal or animal organism uses in their production. It is a fact that the chemist in his syntheses conducts a totally different process from the organism. Why, therefore, may not an especial energy be exerted in the raised by many to-day as it was sixty years ago. Quite This question is organism, the so-called vital force? recently at the opening of the British Association in Manchester, Roscoe said, after a decided rejection of the vitalistic hypothesis:-"We might raise the question whether any limit has been set to this synthetic power of the chemist? ... Though the danger of dogmatising on the progress of science has already been seen in too many cases, we cannot help feeling that the chemist has for the present no prospect of breaking down the barrier which exists between the organised and the non-organised world." Chemistry, as such without calling other facts into play, has certainly hitherto banished an especial vital power into the realm of fable. But if it should happen-and its early occurrence is important-it must be demonstrated that the chemical processes in the vegetal and animal organism must be capable of explanation by the existing natural laws, or by them and possibly by natural laws yet to be discovered and in harmony with them, and that actions and syntheses can be elicited outside of the living in consequence some of the peculiar physiological reorganism exactly as within it. This problem is capable of solution. But we must first apprehend what belongs to the performance of the ordinary chemical reaction; then which of these conditions are wanting or are modified in the chemical transformations in the organism, or if any novel conditions appear. If these differences are clearly shown, then such modified conditions for a chemical reaction can be produced artificially at pleasure; hence there would arise a bio-chemistry very different from and far more manifold than the chemistry of the day. It may here be premised that such modified conditions of reaction really exist in the living cell, and that even in chemical manufactures organism-reactions," accidentally discovered in practice, find their application. In such cases modern chemistry, when questioned concerning their origin, is accustomed to content itself with the phrase," not perfectly explicable." A considerable number of misty conceptions, such as 'katalysis," "power of contact," " ferment," "allotropy," &c., cannot hide the imperfections of such poor attempts at explanation, as they are recognised by every competent and reflective observer. For a chemical reaction to take place a relatively considerable number of conditions must be fulfilled. Το ascertain these we ask what occurs without exception in every chemical reaction; we then exclude strictly whatever is not to be observed in every case.. We then observe that whatever can always be shown in every chemical reaction is indispensable for the occur. rence of such reaction, or is a necessary concomitant phenomenon. Those natural processes which we call chemical reactions must be distinguished from all others by something in a genetic respect, which characterises them as chemical processes, and which must not be wanting if they are to retain this character. This something must be that which always belongs to all chemical reactions. Now it is a common character of all chemical reactions in the customary sense of the word occurring on the earth's surface that : 1. Different materials come in direct contact. 3. There arise electric currents. 4. Changes of volume and of 5. Thermic energy occur. 6. An action of mass is present. In the text-books the chemical reaction, the foundation of chemistry, as such is scantily or not at all discussed. The metaphysical enquiry as to the ultimate ground throws the more proximate question into the shade. The six unconditional requirements of all chemical reactions are here collated probably for the first time. NEWS . seedlings, as the growth of the roots came to a close after the first day. Leaves of Valisneria spiralis, after remaining for three days in the above solution of azoimide salt, had lost their vital turgescence, displayed no plasmatic currents, and the cells were dead. In the check solution, which contained nitrogen in the form of ammonium sulphate, the leaves remained alive and the cells displayed lively plasmatic currents. Leaves of the hazel-nut plant, placed in the solution of sodium-azoamide, showed brown spots after three days. 2. Experiments on Alga. carpus, Oscillaria, also cells of Desmidiaceae (Closterium, A number of threads of Spirogyna, Zygnema, MesoCosmarium, various diatoms (Nasicula, Gomphonema, Odontidium), were placed in well-water containing part It must be asked whether they are always to be found per thousand of sodium-azoimide. After eighteen hours accompanying the chemism of organised matter. not the slightest injurious action could be detected under As the three fundamental functions of protoplasm, that ground-third day could a slowly progressive fading be detected. a magnifying power of 800 diameters. Not until the floor of all telluric life, we recognise :-(a) Change of matter; (b) change of energy; (c) change of form: Even after ten days living cells could still be detected in band c are impossible without a, and a consists of strong granulation of such an appearance as may be the Algæ. The dead cells of the Spirogyra showed a assimilation and dissimilation. observed in the influence of ammonium salts at i part per thousand. (To be continued). In the diatoms and Oscillaria the phenomena of movement did not totally disappear before the fifth day. At the same time the death of the protoplasm of the Desmidiacea was recognised. If the above solution was diluted ten times, and mineral nutrient salts were added (o'1 of each per thousand), the Algæ above named remained living even after three weeks, and were healthy. Filaments of Vaucheria exhibited distinct growth. Very different is the behaviour of the same Alga with hydroxylamine and diamide. By these substances, at the same dilution (or per thousand), the Algæ are killed within forty-eight hours at furthest, even in a perfectly neutral solution. 3. Experiments with Bacteria. One portion of a culture solution of the following composition Potassium sodium tartrate, I per cent; potassium diphosphate, o'1 per cent; magnesium sulphate, 0'05 per cent; calcium chloride, o'05 per cent-was mixed Having been put in possession of some sodium-with o'I per cent sodium azoimide, a second with o'r per azoimide by the great kindness of Prof. Curtius, I resolved to take these questions in hand. 1. Experiments with Phanerogams. A culture solution was made up with magnesium sulphate and potassium monophosphate, o.2 per thousand each; potassium chloride and calcium chloride, o'r per thousand each; and a trace of ferrous sulphate. To this liquid there was added o'2 per thousand of sodiumazoimide; and to a second portion, instead of the lastmentioned substance, an equal quantity of ammonium sulphate. In each solution there were placed three barley seedlings of 3 to 35 c.m. in length. The next day a great difference was visible; the ammonia plants had grown distinctly, and measured on the third day respectively 10, 103, and 107 c.m. The azoimide plants had scarcely grown at all, and measured 3.1, 3.6, and 3'9 c.m. In the length of the roots there appeared an equally striking difference. On the fourth day yellow spots appeared on the leaves of the azoimide plants; and on the fifth day from the commencement of the experiment the plants had faded, and were dying in all parts. The ammonia plants meantime developed in the normal manner. Even three seedlings which had been placed for comparison in well-water, without the addition of any nutrient salts, remained healthy, and grew for some time. Hence sodium azoimide had evidently exerted a poisonous action. A poisonous action was also observed in lupin * Ber. Deutsch. Chem. Gesell. cent diammonium phosphate, and a third with both these nitrogen compounds together. The three mixtures were then infected with bacteria which had grown in a methylic nutrient solution on exposure to the air. After fortyeight hours the second portion showed a strong bacterial turbidity, whilst the microscope showed a vast quantity of bacteria, which quickly effected the fermentation and combustion of the tartaric acid in the nutrient solution. The two others, even after standing for six weeks, and after repeated infection, remained perfectly clear, and developed not a trace of bacteria. Even when the solutions were diluted fivefold, and infected afresh, there were still no living bacteria. They were thus again diluted twofold, so that they only contained o'r per thousand sodium azoimide; 0'5 per cent glucose was added. They were infected again, and let stand for fourteen days in an open flask. No bacterial turbidity appeared, but a few living bacteria were present. That flask which contained ammonia along with the sodiumazoimide displayed a thin film of Saccharomycetes (probably S. ellipsoideus). (To be continued.) A Treatise on Manures.-Messrs. Whittaker and Co. have in the press a second edition of Dr. A. B. Griffiths's "Treatise on Manures." It is a little more than two years since the work appeared; therefore, to bring the new edition up to date, it has been necessary to add fifty pages of new matter. DETERMINATION OF SMALL QUANTITIES By F. MYLIUS and F. Foerster. AFTER a few minutes it is allowed to flow into a second similar parting funnel, where it is shaken with to c.c. of aqueous ether in order to remove again the greatest part of the free eosine taken up by the water at the first shaking. The solution thus twice shaken is lastly collected in a flask in order to compare it with a solution of alkaline eosinate of known strength. Such a comparative solution is made up with a number of c.c. of the above-named For alkaline solution of iodeosine diluted with water. comparison solutions are preferred the colouration of which corresponds to 5-20 c.c. of the original solution in 100 c.c. and strata of liquid of 5-15 c.m. in depth. On account of the small extent of these figures, it is often necessary to dilute the coloured solution in a suitable manner. Here, and in measuring out the comparative solution, it must be remembered that the quantity of liquid used for comparison = IIO C.C. For the purpose of comparison, Wolff's colorimeter is very suitable, in which the adjustment of two solutions for equality of colour is effected by regulating the depth of the strata. As regards the calculation of the determinations which have been carried out by the above-named process, it was already mentioned that we cannot conclude directly the quantity of alkali present from the red colouration of the shaken solution by comparison with a solution of sodium cosinate of known strength and of an equal intensity of colour. Into the watery stratum there passes, as already mentioned, some free eosine, which partly remains there after the second shaking; this introduction is, however, exceeded by the eosine given off to the ether in consequence of the hydrolytic fusion of the alkaline eosinates. Both these influences cannot be calculated, and hence it becomes necessary to multiply the quantity of alkali calculated directly from the red colouration observed by an empirical factor in order to obtain the quantity of alkali really present. In order to find such a factor there were carried out a series of determinations with varying quantities of a solution of soda containing ro m.grm. Na2O per litre. It appeared that on employing every precaution required by the sensitiveness of the method, equal results were obtained under like conditions, though, as it might be expected, the values found show deviations which may amount to 10 per cent of the total. The following table contains the mean values from a series of separate determinations: solution required by pure water, as this difference can only be referred to the alkali present. It is observed that the quantities of alkali computed in this manner approximate very closely to the same fraction of that really present, i.e., on the average 72 4. In order to raise this 72'4 to 100 it must be multiplied with 100/72'4=1*38. Hence I c.c. of the alkaline solution of eosine repre sents 1 An example will explain what has been said. In the above conspectus we find that the colour observed corresponds to 45 c.c. of the eosine solution; as the "eosine value" of pure water 56, the colour corresponding to 39'4 c.c. solution of eosine. If all the alkali the alkali were present as neutral sodium eosinate, I c.c. of eosine 0'00074 m.grm. Na2O; but in fact I c.c. solution would = corresponds to 138 times this quantity of alkali; that is, to o 00102 m.grm. Na2O. Hence 39:4 c.c. correspond to 00402 m.grm. Na2O, and the quantity employed would be o'0400 m.grm. Na2O. How far we arrive at an agreement between the quantities of alkali used and detected will be seen from the following conspectus: LONDON WATER SUPPLY. REPORT ON THE COMPOSITION AND QUALITY OF DAILY By WILLIAM crookes, F.R.S.; and C. MEYMOTT TIDY, M.B., F.C.S., Barrister-at-Law, Professor of Chemistry and of Forensic Medicine at the London Hospital; Medical Officer of Health for Islington. To GENERAL A. DE COURCY SCOTT, R. A., Water Examiner, Metropolis Water Act, 1871. London, November 7th, 1891. SIR, We submit herewith the results of our analyses of the 189 samples of water collected by us during the past month, at the several places and on the several days indicated, from the mains of the seven London Water Com. panies taking their supply from the Thames and Lea. In Table I. we have recorded the analyses in detail of samples, one taken daily, from October 1st to October 31st inclusive. The purity of the water, in respect to organic matter, has been determined by the Oxygen and Combustion processes; and the results of our analyses by these methods are stated in Columns XIV. to XVIII. We have recorded in Table II. the tint of the several samples of water, as determined by the colour-meter described in a previous report. In Table III. We have recorded the oxygen required to oxidise the organic matter in all the samples submitted to analysis. Of the 189 samples examined, all were found to be clear, bright, and efficiently filtered. As a consequence of the exceptionally flooded state of the rivers during the greater portion of the month of October, the character of the water supplied to the Metropolis, in respect to its degree of freedom from organic matter, was on the whole less satisfactory than it has been found for a long time past. The New River Company's supply, though appreciably affected towards the end of the month, maintained a high average standard; while the supply of the East London Company from the Lea, and that of the Chelsea Company from the Thames, were, owing doubtless to the large storage area of these two Companies, not affected by the floods to any notable extent. In the case of the other Thames-supply Companies, in different degrees in different instances, the proportions of organic matter present, as indicated by the degree of colour-tint of the water, and estimated by the combustion and oxidation processes, were appreciably in excess of the proportions habitually met with. The mean proportion of organic carbon present in the Thamesderived supply was o'197 in 100,000 parts of the water, as against a mean of o'129 part in the previous month's supply; while, in two samples, the maximum amounts were found to be 0.395 and 0.422 part respectively,-the variation of amount in the other samples examined ranging from o°143 part to 0.241 part in 100,000 parts of the water. We are, Sir, THE existence of gold in the form of a natural sulphide in conjunction with pyrites has often been advanced theoretically as a possible occurrence, but up to the present time this occurrence has, I believe, never been established as an actual fact. During my investigations on the ore of the Deep Creek Mines, I have found in them what I believe to be gold existing as a natural sulphide. The description of this ore will, no doubt, be of interest to your readers. The lode is a large irregular one of pure arsenical pyrites, existing in a felsite dyke near the sea coast. Surrounding it on all sides are micacious schists, and in the neighbourhood is a large hill of granite about 800 feet high. In the lode and the rock immediately adjoining it are large quantities of pyrophyllite, and in some places of the mine are deposits of this pure white, translucent mineral, but in the ore itself it is a yellow and pale olivegreen colour, and is never absent from the pyrites. From the first I was much struck with the exceedingly fine state of division in which the gold existed in the ore. After roasting and very carefully grinding down in an agate mortar, I have never been able to get any pieces of gold exceeding the one thousandth of an inch in diameter, and the greater quantity is very much finer than this. Careful dissolving of the pyrites and gangue, so as to leave the gold intact, failed to find it in any larger diameter. As this was a very unusual experience in investigations on many other kinds of pyrites, I was led further into the matter. Ultimately, after a number of experiments, there was nothing left but to test for gold as a sulphide. Taking 200 grms. of pyrites from a sample assaying 17 ozs. fine gold per ton, grinding it finely, and heating for some hours with a solution of sodium sulphide (Na2S2), on decomposing the filtrate and treating it for gold I got a result at the rate of 12 ozs. gold per ton. This was repeated several times with the same result. This sample came from the lode at the 140 feet level, whilst samples from the higher levels where the ore is more oxidised, although carrying the gold in the same degree of fineness, do not give as high a percentage of auric sulphide. It would appear that all the gold in the pyrites (and I have never found any apart from it), has originally taken its place there as a sulphide. The following is an analysis of a general sample of the ore : PROPERTIES OF PRECIPITATES, &c.* By E. WALLER, Ph.D. (Concluded from p. 269). SnS2. Rem.-Usually precipitated by H2S in acid solution, or by acidifying solutions of alkaline sulpho-stannate. Obtained for purposes of separation, or for determination as SnO2 after oxidising. Disposition to run through the filter checked by alkaline acetates or nitrates, &c. Cond.-Solution slightly acid, moderately dilute. Precipitation promoted by acetates, interfered with by alkaline oxalates or oxalic acid. Sol.-Moderately concentrated acid, especially HCl, dissolve or prevent precipitation. The influence is more marked the more concentrated the acid, or the higher the temperature. Soluble in a boiling solution containing free H2C2O4. (Separation from Sb.) Ign. If rapidly and strongly heated, some SnS, may be volatilised. By moderate heating with access of air, SnO2 forms without loss. It is, however, usual to assist the oxidation with a few drops of HNO3 added from time to time. Ammonium Phosphomolybdate. 12M0O3(NH4)3PO4+. Rem.-Yellow, finely-crystalline precipitate. Precipitant (NH4)2M004 in HNO3 solution. The ratio of MoO3 to P2O5 in the precipitate varies according to the proportion of substances present in the solution (NH4NO3, Fe2(NO3)6, &c.), the proportion of free acid, the kind of acid, the length of time elapsing before filtering, and the temperature at which it is effected. With the same or closely similar conditions, the ratio of MoO, to P2O, is essentially the same. Precipitation promoted by agitation. When precipitation is complete, the precipitate settles rapidly after stirring. Precipitated under the conditions described by Emmerton (volumetric determination of P in irons), the ratio of MoO3 to P2O5 is 24 to 1. Cond.-Solution should be acid with HNO3. Too much free HNO3 retards, or may prevent complete precipitation; too little allows Fe2O3 to come down with it, in which case the colour is more orange. An excess of the * From School of Mines Quarterly, xii., No. 4. precipitant should be present; also at least 10 grms. of NH4NO3 for every o'i grm. or less of P present. Temperature should be 70-85° C. Below 70° the separation is very slow, whereas on boiling (other conditions being right), MoO3 or Fe2O3 may accompany the precipitate. Reducing agents, organic acids, silica, chlorides, and HCl, should be absent. H2SO4 and sulphates retard precipi. tation. If the precipitate is to be dissolved for volumetric estimation, in a solution of material containing but little iron, some iron should be added to give correct results, or the standard should be obtained with material of the same character. Sol.-Readily dissolved by NH4OH and other alkalies; also by alkaline phosphates. If the ammonia is too strong, however, the solution will be turbid with (NH4)2M0O4. Dissolved or decomposed by water alone, the more readily the higher the temperature. Precipitation prevented by tartaric acid or organic substances of that class. Somewhat soluble in HCl, or moderately strong H2SO, and HNO3. Insoluble in weakly acid solutions and acid solutions of NH4 salts. Solution for washing should contain I per cent HNO3 and 10 per cent NH4NO3, or a corresponding amount of H2SO and (NH4)2SO4 Contam.-Arsenio-molybdate, silica, Fe2O3, TiO2. Arsenio-molybdate precipitates the less readily the lower the temperature. By allowing the solution to stand for about two days at 40° C., the phospho-molybdate may be precipitated free from arsenic. When present, however, As is separated either before or after. Silica, either as hydrated SiO2 or as silico.molybdate (the existence of which is disputed), may be present. By allowing the ammonia solution to stand for some time after addition of NH4Cl, the flocculent silica separates and may be filtered off. bases with the silica is best prevented by drying at 120° C. Some alumina almost invariably remains with the silica if Al is present in the solution. Sol. Dissolved by boiling or fusing with fixed alkalies, caustic or carbonated. Insoluble in water and acids (HFi excepted). Contam.-Insoluble sulphates (PbSO4, BaSO4) removed by digestion with concentrated H2SO4, and filtering through asbestos. (For other solvents of these substances, vide sup.) In some cases CaSO4, removable by digestion with HCI and NH4Cl. The precipitate may also contain a form of Fe2(SO4)3 (when separated from concentrated H2SO4) which dissolves in dilute H2SO4 with some difficulty, but is readily soluble in HCI. SnO2 or Sb2O4 may be retained, as well as TiO2 (possibly combined with P2O5) and ferric or aluminic oxides or basic salts. TiO2 tends to hold P2O5,Al2O3 and Fe2O3 in the precipitate. To avoid error in such cases the SiO2 should be determined by loss, adding HF or NHF (and in any case H2SO4), igniting off SiF4, and weighing again. This treatment is advisable whenever Al2O3 is present in the solution in any quantity. Ign.-Precipitate is very light and fine, and readily carried off by flame, requiring especial precaution on igniting. After ignition, the precipitate will absorb appreciable amounts of water if exposed to air containing moisture. ON THE OCCURRENCE OF NITROGEN IN URANINITE, AND ON THE COMPOSITION OF URANINITE IN GENERAL.* By W. F. HILLEBRAND. (Continued from p. 257.) X. XI. Fe2O3 in the precipitate often causes it to separate in crusts on the sides of the beaker. On attempting to dissolve in ammonia, yellow to red Fe2(OH)6 mixed with TABLE III.-Uraninite from Colorado and North Carolina. Fe2(PO)2 remains undissolved. After washing with ammonia this residue is dissolved in HNO3, the solutions united and re-precipitation effected, after acidifying with HNO3. Hydrated TiO2 (which retains P205) can be separated by fusing the portion insoluble in ammonia for some time with Na2CO3 (vide Na2TiO3), leaching with water, and in the water solution re-precipitating with the molybdate reagent. SILICA. Rem. and Cond.-On adding an excess of mineral acid to a solution containing a silicate, free silicic acid containing indefinite amounts of water is formed, partially or entirely soluble. On evaporation H2O (of constitution) is removed and insoluble SiO2 is separated, which may be filtered off after digestion with diluted acid. HCl is the acid most frequently used. When HNO3 is used, regard must be had to the fact that certain nitrates (Fe2(NO3)6, &c.), are decomposed at the temperature usually employed to drive out the last portions of the water (110-130° C.), and are not readily re-formed by digestion with diluted HNO3. The heat is usually maintained until there is no perceptible odour of acid. With H2SO4, the heat is continued until fumes of SO3 are evolved, indicating that H2SO4 is the only free acid remaining. If the heat has not been sufficiently prolonged or intense, the separated silica may be flocculent and filters with difficulty, or some may remain soluble. If the heat has been too high, the conditions may have favoured a re-combination of silica with the bases, and consequent soluble silica (analogous to the action by fusion). The temperature which can safely be applied may be put at 110-120°. According to Gilbert (Technical Quarterly, February, 1890), when only Ca and alkalies are present, the temperature of drying may be carried up to 280° C. without detriment; but if Mg is present, re-combination of the UO3 UO2 ZnO FeO CaO MgO IX. Colorado. a. b. 25.26 North North Mean. Carolina. Carolina. 25.26 50'83 44'II 58.47 58.56 58.51 39°31 46.56 TiO 2 ZrO2 Tho2 2.78 0.69 0'71 0'70 MnO |