uestions such as these :-Suppose in a trigonal or hexagonal system that other planes of symmetry intersected with the planes S and C at crystallometric angles; or, again, suppose in the tetragonal system that the plane C were to become conformable with either the S or the group of planes, in which case new planes of symmetry would intersect at 45° with the planes in question in their zone axis; and every supposition that we can frame of this kind would readily receive an answer from trigonometry. The principle of a systematic triangle that has been introduced in previous lectures enables us, however, to deal with this problem from a more general point of view. Since the systematic triangle represents the smallest spherical triangle that any system admits of, of which the kinds of systematic triangles. They will be severally represented by figures. But it will be seen that great circles passing through the poles h, in pairs, are potentially also planes of symmetry, and in this case the two kinds of symmetry under consideration become identical; since the zone circles [hh], Fig. 14, will bisect each and every of the systematic triangles in the former of the two cases, forming new systematic triangles which fulfil the conditions of having their angles crystallometric. This condition, however, is not fulfilled by the zone circles passing through adjacent pairs of poles, d, since the spherical triangle formed by the sides d t, do, ot, in Fig. 14, has its angle at d=67 30, which is not a crystallometric angle; nor are the adjacent spherical triangles repetitions by symmetry of this triangle. It results from this that the The characters of the several forms the poles of which lie on the arcs or at the angles of the systematic triangles were next considered, though not in detai!, since their descriptions are to be obtained in any of the ordinary works on crystallography. poles o are poles of trigonal, but not of hexagonal, sym-) system are so far isomorphous. If all the permutations metry: the poles h, on the other hand, are tetragonal that can be performed on the position of the indices in poles, and the poles d are ortho-symmetrical in character. the symbol hk of the hexakis-octahedron be combined In fact, the system under discussion presents us with three with all the different varieties in sign which those indices planes of symmetry, containing the zone circles, [hh], can undergo, it will be found that a symbol will be obperpendicular to each other, which we may call the proto-tained for each one of the forty-eight faces, with a detersystematic planes S; and, further, six planes of deuterosymmetry, 2, intersecting in triads in the axes [o] and in minate position on the sphere. pairs perpendicularly in the axes [h], in which they intersect at 45° with the great circles S, each plane again meeting a plane S perpendicularly in a zone axis [d]. The poles hand o represent those of the well-known figure, the cubo-octahedron; the poles d are those of the rhombic-dodecahedron, or 12-1aced rhombohedron. Fortyeight systematic triangles partition the surface of sphere, so that the most general form of this system-and therefore, also, the most complex single form in crystallography —is the 48-faced scalenohedron, known as the hexakisoctahedron (hkl). The planes S are naturally axial planes of the system; they are parallel to the faces of the cube, and the crystallographic axes are their normals. A face of the octahedron intersects at equal distances with each of these axes, so that the parameters of the crystal are equal. Taking h>>4, the symbol (kk) was that of the 24-faced figure, the icositetrahedron; the form {hhl} being that of the triakis-octahedron, and the form {h ko that of the tetrakis-hexahedron: the poles h of the cube belong to the form {100}; the poles d of the rhombic-dodecahedron to the form {110}; and the poles o of the octahedron to the parametral form (III). I I Of the merosymmetrical forms of this system, the a symmetrical kind being unexemplified in Nature, the holoFIG. 14. sides K The systematic triangle has, as we have seen, for systematic hemihedral forms, including the tetrahedron, III, the hexakis-tetrahedron x {hk 1}, the trigonal dodecahedron hkk, and the triakis-tetrahedron H=35° 15' 35" D=54° 44' 15" =1) K hh, were alluded to. In them the S planes are only potential, while the planes are actual planes of symmetry. The hemi-systematic forms-in which the planes are potential, while the planes S are actual planes of symmetry-are centro-symmetrical; such are {h}, the dyakis-dodecahedron, and hko, the pentagonal dodecahedron, a figure not to be confounded with the regular dodecahedron of geometry. A tetartohedral form exists in this system, the dyakis-hexahedron (hkl), consisting of twelve irregular pentagons. It КП π is remarkable, in this respect, that the crystals which carry it as a form exhibit rotatory polarisation similar to that exhibited by quartz. ERRATA.-P. 64, col. 2, lines 13 and 14 should read as follows:-"symmetrical to S, and potentially to a plane of which n is the pole. Som and are possible planes, and, on the assumption of," &c. P. 102, col. 2, line 14 from bottom, for its read each. P. 102, col. 2, line 10 from bottom, for signs read sides. P. III, col. 2, line 7 from bottom, for c read C. ON THE OCCURRENCE OF PHOSPHATES IN THE CAMBRIAN ROCKS.* By HENRY HICKS, F.G.S. In this paper the author showed from experiments that the Cambrian strata in Wales contain a far greater amount of phosphate and carbonate of lime than had hitherto been supposed. The results published by Dr. Daubeny some years ago, and which have since received the support of some eminent geologists, were proved therefore to be entirely fallacious when taken to represent the whole Cambrian series; for though some portions show only a trace of these ingredients, there are other beds both interstratified with and underlying these series, which contain them in unusually large proportions. The author, therefore, objects to look upon Dr. Daubeny's experiments as tending in any way to prove that the seas in which these deposits had accumulated contain but little animal life, and that we had here approached the borders of the lower limit of organic existence. He contended that the presence of so much phosphate of lime, and also of carbonate of lime, as was now proved by analyses made by Mr. Hudleston, F.C.S., Mr. Hughes, F.C.S., and himself, to be present in series of considerable thickness in the Longmynd group, Menevian group, and Tremadoc group, proved that animal life did exist in abundance in these early seas, and that even here it must be considered that we were far from the beginning of organic existence. The amount of phosphate of lime in some of the beds was in the proportion of nearly 10 per cent, and of carbonate of lime over 40 per cent. The proportion of phosphate of lime, therefore, is greater than is found in most of what have been considered the richest of recent formations. The amount of P205 was also found to increase in proportion to the richness of the deposit in organic remains. It was found that all animal and vegetable life had contained it from the very earliest time; but it was apparent that the Crustacea were the chief producers of it in the early seas; and of the Crustacea, the trilobites more particularly. It was always found where they were present, and the shell of some of the larger trilobites, as now preserved, contain as much as from 40 to 50 per cent of phosphate of lime. The analyses made by Mr. Hudleston and the author of recent Crustacea proved that they also contain P2O5 in very considerable proportions. In the second part of the paper the author showed that where intrusive dykes had passed through or between the beds containing the phosphate of lime, the beds for some distance on each side of the dykes had undergone a considerable change. Scarcely a trace of the P205 or of the lime was now to be found in them, though it was evident that before the intrusions into them had taken place, they, like the other portions of the beds, had evidently contained both ingredients in considerable proportions. It was well known that heat alone could not separate P2O5 from lime; therefore he found it difficult to account for this change in the character of the beds, unless it could be produced by gases or watery vapour passing into them at the time the intrusions took place. He thought it even probable A Paper read before the Geological Society of London, March 24, 1875. that the dykes, which in some parts are found to contain a considerable amount of lime and also P2O5, might have derived these, or at least some portions of these, from the beds through which they had been forced, and which must have been broken up and melted as they passed known in Wales of earlier date than the Llandeilo beds; through them. There are no contemporaneous tuffs and he thought these dykes belonged to that period, and that they were injected into the Lower Cambrian beds. after from 8,000 to 10,000 feet of deposit had been superimposed. In an agricultural point of view the author considered that the presence of so much phosphate of lime in some of the series of beds must be a matter of great importance; and on examining the districts where these series occurred, he invariably found the land exceedingly rich. Mr. Hudleston gave the results of the analyses made by him at the request of Mr. Hicks. He found in a portion of dark grey flaggy rock taken from close to a fossil 162, in a portion of black slaty rock containing trilobites, but in contact with trap o'11, in a portion of the shell of a trilobite 17.05, and in the trap above mentioned 0.323 per cent of phosphoric anhydride. A lobster-shell dried at 100° C. gave 3.26, an entire boiled lobster (undried) 0.76, and a boiled lobster without shell o'332 per cent of P205. If the analysis of an entire lobster be correct, he estimated of phosphoric anhydride. In the analysis of the shell of that a ton of boiled lobsters would contain about 17 lbs. a trilobite there appears to be a great excess of phosphoric acid, which Mr. Hudleston thought must be due to sub stitution. Prof. MASKELYNE said that the solution of the question of the diminution of the phosphate of lime near intrusive rock was easy. The intrusive rock in cooling would contract, and thus facilitate the percolation from above or the forcing up from below of water, which flowing through the adjacent rocks would dissolve out the phosphate of lime. He remarked that north of Cardigan Bay pisolitic iron ore was found charged with phosphate of lime. Mr. D. FORBES stated that when, many years ago, Dr. Daubeny maintained that the Cambrian rocks only con (in 1857) chemical analyses of some of the oldest then tained mere traces of phosphoric acid, he had published known limestones, showing that these contained quite as that the larger proportion of phosphate of lime found in much phosphoric acid as recent ones. He considered the fossil Crustacea, as compared to the recent, was mainly due to the fact that, besides the organic matter, carbonate of lime had also been removed from them; and that the reason of the casts of Paradoxides near dykes of igneous rock containing only traces of phosphoric acid and lime was rather the removal of these substances by water than the igneous action of the dyke. He could not eruptive rocks was derived from the sedimentary fossilagree in believing that the phosphoric acid found in iferous beds through which they passed, but regarded it Even the Menevian and Laurentian rocks were after all as an inherent constituent of the eruptive rock itself. only made up of the debris of previous eruptive rocks; and he looked upon the eruptive rocks as the original source of all the phosphoric acid assimilated by animal and vegetable life. He regarded this paper as a most valuable contribution to geological science. obtained by Mr. Hicks. Mr. Kocн enquired whether any Vivianite had been Prof. SEELEY thought that the paper, interesting as it phosphate of lime in phosphatic deposits, especially such was, did not bring us any nearer to the source of the the Bala beds. The proportion of phosphoric acid in the as those recently described by Mr. Davies as occurring in ash of the lobster did not appear to be greater than in that of plants; and whilst the debris of marine animals would be rapidly dispersed, those of seaweeds would remain at the bottom, and it was to these that he was inclined to attribute the accumulation of phosphate of NEWS lime in these deposits. At the same time he believed that the phosphoric acid was primarily derived from volcanic rocks, out of which the phosphates have been washed by water. The great proportion of phosphate of lime in the shell of the trilobite was probably due to infiltration. Mr. HUGHES said that he had examined many soils in Australia and elsewhere, and that when the soil was deficient in phosphate of lime the underlying rock was the same, but when the soil was rich in phosphate the rock also contained it. He had also found phosphoric acid in igneous rocks from the north of England and Scotland. Mr. TOPLEY enquired as to the amount of phosphoric acid in the flesh of the lobster. He remarked that the shells of the gault were largely phosphatised, and that they seem to have drawn their phosphoric acid from the surrounding rock. There are many phosphatic nodules in the lower part of the gault, and also on the surface of the Kentish rag. The AUTHOR, in reply, said he thought it possible that water, or rather watery vapour, may have washed out the phosphate of lime from the altered beds; but he contended that this must have taken place at the time the intrusions occurred, for at present these beds are as solid and impervious to water as are the beds in which the phosphate of lime is now present. He stated that he did not intend to say that there were no contemporaneous traps of so old a date as the Menevian beds, but that there were none in Wales of earlier date than the Arenig or Llandeilo series; he had even mentioned that there were some in Canada of the age of the Laurentian rocks; but as there was no evidence of any of these in Wales, we could not look upon the phosphate of lime in these beds as having been obtained from dissolved apatite. In reply to Prof. Seeley, he said he could not allow that some beds lost all their phosphate of lime by percolation of water, and that the fossils in the others obtained it by the same means. He did not suppose, however, that all the phosphate of lime present in the fossil shell occurred in the natural shell, and he believed that it had to some extent in the process of fossilisation replaced carbonate of lime. Mr. HUDLESTON, in reply to Mr. Topley first, said that his calculations of the percentage of phosphoric acid in the lobster were based upon the amount compared with the total contents of the animal itself, as this seemed the most suitable for purposes of geological inquiry. That ratio once established, other calculations might be made. The phosphates in these as in other sedimentary rocks must be regarded as a sort of residuum or ash, the result of the decomposition of nitrogenous organic matter which was left after the more volatile carbon, hydrogen, nitrogen, and oxygen had, under various combinations, more or less completely disappeared. Calcium phosphate is known to be the chief constituent of the ash of most albuminous principles; analyses of these were quoted. The question of the loss of phosphoric acid in the rock adjoining the trap was one of much difficulty; but as an instance somewhat similar, Bischof was quoted to the effect that large quantities of calcium phosphate occur in basalt in the vicinity of a guano deposit at the Isle of Ascension. THE COKE-MANGANESE GALVANIC CELL. By SERGIUS KERN, St. Petersburg. THE well-known Leclanché's cell is now in use for many purposes, giving a very constant current, but which, however, is much decreased by the resistance of the tar covering the top of the porous cell, and by the decomposition of the manganese dioxide, which is transformed during the action of the cell into manganous oxide; the latter oxide closes the pores of the cell. My cell is a modification of Leclanché's one, and the experiments proved it to act very constantly. Two parts of cleanly washed coke, and one part of | manganese dioxide (MnO2) in the state of powder, are well mixed together with a small quantity of water acidulated with some drops of nitric acid; the mixture then is strongly pressed into brown paper cartridges 0.125 metre high and o'03 metre diameter. The resulting coke-manganese cylinders are dried in a warm place, but not over a fire, because the heat, as it is known, decomposes the manganese dioxide. The dried cylinders are placed in glass jars containing concentrated solution of ammonium chloride (NH3HCI), and surrounded with zinc-plates curved in the usual manner. By this arrangement the use of porous cells is avoided, and a battery of such elements acts more constantly; besides this, the construction of it is cheaper. Instead of having glass jars, I am using wooden boxes, the size of the glass jars; the internal parts of the boxes are covered with the following mixture, melted in an iron cup-2 parts of wax, 10 parts of common resin (colophony), 2 parts of red-lead, and part of gypsum. The zinc of the element is the negative pole; the coke, the positive pole. The reactions which take place in this element may be represented by the following equations :2NH3HC1+2Zn=2ZnCl2+2NH3+H2; H2+MnO2 = MnO+H2O. DEVELOPMENT REPORT ON THE OF THE CHEMICAL ARTS DURING THE LAST TEN YEARS.* By Dr. A. W. HOFMANN. The Elements of Water. By Dr. A. OPPENHEIM. Oxygen.-Like the evolution of human life, the development of every chemical art is connected with oxygen; Directly or indirectly, it intervenes in every manufacturing operation. With equal necessity, life and technology derive it from that exhaustless source of all being, the atmosphere. Furthermore, no discovery has had a greater significance for the history of culture than that of the material nature of the air, and the discovery-the centenary of which we commemorate this year-of its most important constituent, oxygen gas. To the same discoveries chemical industry owes its rational foundation and the possibility of its advancement, and thus both the existence and the progress of technology are linked to the same element. What, in comparison with these incalculable benefits, are the advantages which pure oxygen gas has conferred upon industry by its direct application? To give a reply to this question is the object of the following lines, and as no reports or text-books have hitherto treated this subject in a connected manner, we may venture to exceed in point of time the boundaries of this report. Lavoisier, who first recognised in its full extent the importance of oxygen, took the first successful step in its technical application. "It is evident," he writes, "that atmospheric air is not the most suitable to increase the action of fire, and that, if we drive a current of air upon ignited fuel by means of bellows, three parts of injurious, or at least useless, gas are driven in for one part of the serviceable kind of air, and that, therefore, if the latter could be used for combustion in a pure state, the action of the fire would be much enhanced. This idea has doubtless occurred to many persons prior to myself, and I "Berichte über die Entwickelung der Chemischen Industrie Während des Letzten Jahrzehends." +"Die Elemente des Wassers." + "On the 1st of August, 1774, I endeavoured to extract air from mercurius præcipitatus per se."-Joseph Priestley, Experiments and Observations on Air," ii., 106. See also Kopp, "Geschichte der Chemie," iii., 200 and 204. "Memoire sur un Moyen d'Augmenter Considérablement l'Action du Feu et de la Chaleur dans les Operations Chimiques."-" Oeuvres de Lavoisier ii., 425. hear that Archard, the celebrated chemist of Berlin, has carried it into application;* but it is still needful to devise a cheap and convenient apparatus." For this purpose, Lavoisier used at first bladders fitted with tubes and taps. "I made," he continues, "with a knife, a hole three to four lines deep in a large piece of charcoal, and laid in it 6 grs. of platinum, set fire to the charcoal at an enameller's lamp by means of a blowpipe, opened the jet of my apparatus, and blew pure oxygen into the hollow. The charcoal burnt very rapidly, with detonation as it produces with melted saltpetre, and with a dazzling brilliance; and in a few moments the platinum melted into granules, which then united into a ball. The fusion was equally successful, whether the ordinary platinum of commerce was taken or such as had been previously freed from magnetic particles by means of a magnet. Hitherto, platinum has not been melted." Lavoisier improved his apparatus in the same year,t in conjunction with Meusnier, and produced a gasometer consisting of two boxes, and which on a small scale much resembled those now in use at gas-works. About the same time, Saron constructed two blowpipes (chalumeaux), one of which delivered oxygen and the other hydrogen. By their means, however, Lavoisier did not succeed in fusing platinum. He hoped, however, to construct an improved blowpipe, in which the oxygen should surround the hydrogen, and thus was developed the plan of the oxyhydrogen blowpipe, which has rendered such essential service in the metallurgy of platinum and in soldering lead. The application of oxygen for melting platinum remained dormant until, in 1857 to 1859, Deville and Debray made known their important investigations on the platinum metals, and introduced the industrial fusion of platinum. The autogenous soldering of platinum, and the production of fused ingots on the large scale, was first carried out by Johnson, Matthey, and Co., of London, and also by Heraeus, of Hanau, in Germany. Debray's and Deville's experiments led, above all, to the discovery of a refractory material for crucibles and furnaces. For this purpose quick-lime offered itself, which has the further advantage of retaining the heat as completely as possible. The chemists above-named increased the heat further by leading the flame from above directly upon the surface of the metal, and determined the amounts of oxygen and hydrogen theoretically and practically necessary for melting 2 kilos. of platinum, i.e., by calculation, 55 litres of oxygen and 11c of hydrogen. The amount actually fused was more than 1 kile, so that -a highly favourable result-not 50 per cent of the heat produced was wasted. These experiments had a further bearing upon the industrial history of oxygen, as they led to the comparison of the cost of the methods of its production and to the search for a less expensive process. We may divide the known methods into chemical and mechanical, subdividing the former into continuous and interrupted procedures. (To be continued.) Inaccuracy of Determinations of Nitrogen in Manures.-A. Bobierre.-The author shows that in the analysis of oil-cake, a smaller or larger portion of the ammonia liberated may be dissociated, according to the conditions under which the combustion is carried on. The losses may amount to 24 per cent of the total nitrogen in the sample. To avoid them it is necessary not to use too long a combustion-tube, to employ a gas- instead of a charcoal-furnace, and to conduct the operation rapidly. -Comptes Rendus. * Memoiren der Berliner Academie, 1779. "Sur un Nouveau Moyen de Produire avec une tres Petite Quantité de Charbons une Chaleur," &c. + Lavoisier, "Oeuvres," ii., 432. : Lavoisier," Oeuvres," ii., 430. PROCEEDINGS OF THE NEWS SOCIETY OF PUBLIC ANALYSTS. ON Wednesday last, the 5th inst., an ordinary general meeting of the Society was held at Cannon Street Hotel. The President (Dr. REDWOOD) was in the chair, and the meeting was numerously attended by members from various parts of the country. The minutes of the last meeting having been read and confirmed, Mr. WIGNER (Joint Secretary) read the fol lowing report of the Council: TO THE SOCIETY OF PUBLIC ANALYSTS. GENTLEMEN, The Council beg to present a Report of the steps they have taken since our last meeting, on February 5th, in reference to the proposed repeal of the "Adulteration Act, 1872," and to the " Sale of Food and Drugs Act, 1875." At that date it will be remembered that, though an intimation had been given of the probable introduction of a new Adulteration Bill, the draft of such Bill was not printed, and its provisions were therefore entirely unknown. Considering it desirable, however, that the views of this Society should, if possible, be embodied in the Bill on its first seeing the light, rather than in subsequent amendments, we addressed a letter to the Secretary of the Local Government Board, requesting him to receive a deputation for the purpose of hearing certain representations which we were prepared to make, as to some features which we considered it important should appear in the new Bill. For convenience, we classified the points referred to under thirteen heads. To this letter we received a most courteous reply from Mr. Clare Read, conveying the thanks of the President of the Local Government Board for the suggestions we had offered, and expressing his hope that many of them would be found to be met in the forthcoming Bill, of which Mr. Read promised to send us an early copy. Agreeably with this promise Mr. Read forwarded to us, on the 16th of February, a draft of the Sale of Food and Drugs Bill." Seeing at once the urgency of our immediately taking this Bill into our consideration, the Secretaries summoned a Council meeting by telegraph, for February 18th. At this meeting, which was a protracted one, the Bill was debated clause by clause, and, as a result, the Secretaries were instructed to urge upon the Government-either orally or by letter, or by both means-certain amendments in the Bill, which appeared to the Council to be of vital importance. Conformably with this instruction the Hon. Secretaries sought and obtained an interview with Mr. Read on the following day, being the date fixed for the second reading, when various points were urged upon him. To the reasonableness of some of these amendments he at once assented, and promised a full consideration to the whole of them. The Secretaries, not being content to rely wholly upon Government support, had an interview with Dr. Lyon Playfair, who went at great length and with much interest into the matter, and whose speech on the second reading displayed an ability and a comprehensive grasp of the subject unapproached by any other speaker. A further Council meeting was held on March 2nd, when Mr. Wigner submitted a form of certificate as an amendment to the one printed in the Schedule of the Bill. requested to transmit a copy of the same to the Local This was unanimously adopted, and the Secretaries Government Board, together with some further suggestions for amending the Bill. The Bill being now fairly before the public, articles appeared in many of the newspapers severely criticising its provisions. Amongst others the Times published a very able article on the subject, which, however, contained Deville and Debray, 1859, Ann. Chim. Phys., Ivi., 395. Dingler's what appeared to be a reflection on the Public Analysts, Polyt. Journ., cliv., 130, 199, 287, 383. |