2 erties of ruled spaces. He defines a point a, and a plane a through this point, as a couple, which he indicates by the symbol (a, a). Among the couples situated upon a straight line A (i.e., the point a lies on a straight line A, which is itself contained in the plane a), there is a simple infinity satisfying a given condition; their aggregate constitutes a correlation. If this condition consists in the equality of the anharmonic ratios of the four points and the four planes of four arbitrary couples of the correlation, the correlation is said to be anharmonic. An important application is made of a theorem of Chasles', concerning the distribution of the tangent planes to ruled surfaces. If u1 u2 uз u are parameters upon which depend a knowledge of a right line (u), and u1 + du1, etc., those which refer to an infinitely near line (u+du), the vanishing of a homogeneous function of the differentials du expresses a property of the system of lines (u) and (u+du), and, consequently, of the correlation which they determine relatively to one of the group (u). The differentials du, or finite quantities t proportional to them, may be considered as homogeneous co-ordinates of the different anharmonic correlations existing upon the line u. Among these correlations those which destroy one or two kinds of t-co-ordinates constitute, respectively, a plexus or a series of correlations. These plexi and series replace the cones of elementary directions in punctual space. The condition for the meeting of two lines (u) and (u+ du) is expressed by the vanishing of a quadratic form N(du); and, obviously, all forms such as KN(du), where K is only a function of the variables u, express the same property. The author remarks that it is possible to choose K in such a manner that the resulting form shall represent the moment of the two lines: i.e., the product of the shortest distance between them by the sine of the angle of their mutual inclination. A number of analogies are here given with punctual spaces. The author makes use of a theorem of Sturm's, concerning pencils of lines; and, particularly, of a method of Darboux', referring to the linear representation of surfaces. A special system of co-ordinates is examined, in which the linear complex possess the properties of spheres; and from this is deduced a system analogous to pentospherical co-ordinates, of which the Plückerian coordinates and Klein's sextuply-orthogonal system are particular cases. The third part of the memoir refers entirely to infinitesimal properties of the second order. The problem treated is an extension of the theory of geodesics, and conducts to a geometrical interpretation of Lipschitz' normal co-ordinates. (Bull. sc. math., etc., 1882.) T. C. [289 PHYSICS. (Photography.) When a Photographic halos and reversals. brilliant point of light is photographed, we often find that it is surrounded by a black circle on the negative, whose inner edge is distinctly marked, while its outer shades off imperceptibly into the surrounding regions. Capt. Abney shows that this is not a diffraction phenomenon as has been asserted, but is due to reflection from the back surface of the glass; and that the diameter of the ring depends on the thickness of the glass, and on its critical angle of reflection. All trouble from halos may be avoided by coating the back of the plate with Brunswick black, which reflects back no light to the film. It is a well-known fact, that, if we greatly over-expose a plate, we shall get a reversal of the image, the lights taking white, and the shades black, instead of vice versa as usual. Now, it has been shown that this is due to the action of the bromine, which has been freed in the lower layers of the film by the action of light, and rises, attacking the metallic silver and sub-bromide in the upper layers. This difficulty is avoided by soaking the film in a solution of potassium nitrite, which absorbs the bromine as fast as it is formed, and before it can do any damage. — (Brit. journ. phot., Jan. 5.) W. H. P. [290 Keeping-qualities of gelatine plates. — Mr. William Brooks has been making some experiments on the keeping-qualities of gelatine plates, and finds, that, though they may work well for a few months, they become slower after that time, the images thinner, and that they develop a tendency to fog. Emulsions were made up with the different silver salts and it was found that plates coated with the pure bromide of silver would keep well for six months; those coated with bromo-iodide would keep four months; those with bromo-chloro-iodide, three months; and bromo-chloride, two months. The latter plates gave by far the best results when new; but unexposed plates very soon deteriorated, especially if the weather was damp. (Brit. journ. phot., Feb. 2, 1883.) W. H. P. [291 Lead as an intensifier. - Herr Grebner recommends the following intensifying solution: nitrate of lead, 4 parts; potassium ferricyanide, 6 parts; water, 100 parts. When this solution has acted sufficiently long upon the plate, it is taken out and washed; it is then placed in a mixture of one part of a saturated solution of potassium chromate, and five parts of ammonia, after which it is washed for a short time. If washed too long, the film has a tendency to peel. This formula is applicable to collodion plates. — (Brit. journ. phot., Feb. 2, 1883.) [292 W. H. P. determined by Gauss's method. The author claims, that in a resistance of one to five ohms the fractional error would be within Too.-(Comptes rendus, xcv. 23.) Another method, by the same author, is to revolve a coil inside of a bobbin which carries a current passing through the resistance to be measured. The current induced in the revolving coil is opposed to the difference of potential at two points in the resistance to be measured. The condition of equilibrium is r = 2n CS, where n is the velocity of rotation, S the distance between the points of contact, and C a constant of the bobbin. The author gives an experimental method of finding S', the value which S would assume if the bobbin were extended to infinity in both directions. The value of C for such a bobbin is 4 d being the distance between two turns of the wire. (Comptes rendus, xcv. 26.) J. T. π d' [293 Aërial navigation by electricity.-M. Gaston Tissandier has found that an electric motor of the Siemens pattern, driven by a bichromate battery, the whole not exceeding the weight of three men, is capable of furnishing regularly for three consecutive hours the work of twelve to fifteen men. A balloon of 900 cub. m. capacity could raise in the air such an apparatus with the additional load of two or three men. M. Tissandier is now engaged in the construction of a gas-generator; after this is completed, he hopes to construct an elongated balloon to which he can apply his machinery. (Rev. électr., Jan. 27, 1883.) J. T. [294 Cost of electric lighting. - Dr. Siemens, in his address to the London society of arts, showed that arc-lamps were cheaper than incandescent lamps, and that both would be decidedly cheaper than gas-lighting if the electric companies had the opportunity to make sufficiently large plants, and the gas companies continued to pay their present large dividends.-(Rev. électr., Nov. 25, 1882.) J. T. [295 New electric lamp. - Mr. Charles Lever of Manchester has invented and patented an electric lamp in which the carbons are held apart by a spring when no current is passing. The current, when first started, excites an electro-magnet which releases a clip, and allows the upper carbon to fall upon the lower; the weakening of the magnets consequent on shunting the current through the carbons allows the spring to bind the clip, and draw back the upper carbon to the proper distance. When the carbons burn away so as to increase the resistance greatly, this process is repeated. (Rev. électr., Jan. 6, 1883.) [296 J. T. Electric torpedo-boat.—A torpedo-boat has just been satisfactorily tried at Constantinople, in which a Siemens electro-motor drives two screw propellers in the rear of the boat. The vessel is cigar-shaped, and moves under water at the rate of eight knots an hour. Its path is traced in the day-time by a wire which projects above the surface, and is followed by a telescope; in the night, by a lantern having an opening only towards the shore, and a light too feeble to betray itself to the enemy by reflection. The place in which the torpedo-boat was tried furnished a severe test on account of the strong currents, which vary in direction in different parts of the channel, and in strength from one part of the day to another. The wires conveying the explosive discharge are, of course, distinct from those carrying the motive current. (L'Electricité, Jan. 6, 1883.) J. T. [297 Electro-magnetic theory of light.-J. W. Gibbs continues his mathematical treatment, obtaining in this paper as the general equation of monochromatic light in a medium of any degree of transparency:— 4 π2 Pot [U]Arev [9] Ave = [U] Ave +[U]Ave, p2 where and denote linear and vector functions; Pot, the operation by which the potential of a mass is derived from its density; q, the actual potential; U the electrical displacement; and p, the period of the luminous disturbance. The symbol [ ] Ave denotes a space-average taken through a sphere of unit radius concentric with the point considered. This treatment removes certain objections to the electro-magnetic theory raised by Lorentz and Rayleigh. The equation, however, is not claimed to be rigorously general. (Amer. journ. sc., Feb., 1883.) J. T. [298 u the angle of the magnetic axis with the axis of rotation, hand h' the cosines of the angles which these two axes make with the radius vector from the earth's centre. (Comptes rendus, xcv. 23.) J. T. [299 Distortion of the spark by statical electricity. - M. Aug. Righi argues, that the spark of a disruptive discharge ought to be acted upon by neighboring statical charges, as if the spark were a body electrified to the same sign as the electrode whose electric density before discharge is stronger. Experiments in which one electrode of a Holtz machine is connected with the earth, and also where one electrode has a greater curvature than the other, confirm his conclusions. (Comptes rendus, xcv. 24.) J. T. [300 ENGINEERING. Regulation of rivers, and prevention of floods. A valuable report upon the rectification of the Rhine and Danube has been made by M. Gustave Wex, privy councillor to the emperor of Austria, in which an account is given of the work carried on between Mannheim and Basle during the period from 1819 to 1863, by which the distance has been shortened from 252 to 169 kilometers, and the fall increased by thirty per cent. The stream has moreover been confined to a uniform channel, the banks being carefully protected, and the old bed with its branches filled, and the land thus reclaimed brought under cultivation. Government considers that the benefits from the change are so large as to make ample payment for the outlay. Similar work upon the Danube has been in progress from 1869 to 1881. The author concludes, that from 48 years of observation and experience of extensive works undertaken for the improvement of rivers, it can be confidently stated that by careful study, even the most tortuous rivers and the swampiest valleys can within a few -(Van years yield the most satisfactory results. Nostrand's eng. mag., Feb., 1883.) G. L. V. [301 The preservation of timber.-A committee of eight members of the Amer. soc. of civil engineers has made a preliminary report upon the above matter, in which a list of thirty-three different chemical processes is presented for preserving wood from decay. The census of 1880 has shown the need of a far more economical use of timber in this country than has prevailed heretofore. Not less than a thousand circulars were sent out to civil engineers, railroadsuperintendents, dealers in timber, and chemists; and numerous letters from engineers are given, in regard to the duration of wood under various conditions. (Trans. Amer. soc. civ. eng., Oct., 1882.) [302 G. L. V. New harbor at Vera Cruz, Mexico. — The plans of Mr. James B. Eads for a new and extensive artificial harbor at Vera Cruz have been for some time before the engineering world, and the work was commenced last autumn. The natural harbor is exposed to gales from the north and north-west, and is often made very dangerous during storms. The plan of Capt. Eads provides for a quiet harbor with deep water and suitable lights for guidance of shipping. The cost of the above works is reckoned at about ten millions of dollars. - (Engineering, Nov., 1882.) [303 G. L. V. phosphorus trichloride to aniline was heated over a free flame in a porcelain dish, and the orange-yellow product boiled with alcohol. On adding water a white precipitate of the above composition was thrown down. This substance is not acted upon by aqueous potassium hydrate nor by dilute sulphuric acid, but it is decomposed by strong nitric acid. (Harvard chem. club; meeting Jan. 9.) [304 Phenoxybromacrylic acid.- Professor Hill described phenoxybromacrylic acid which he had obtained by acting upon mucobromic acid with potassium phenolate, and treating with potassium hydrate the product thus obtained." He proposed to study it more carefully with the hope of establishing the relative position of the bromine atoms in mucobromic acid and the connected dibromacrylic and dibrommaleic acids. (Ibid; meeting Jan. 23.) (Analytical.) [305 Quantitative determination of calcium. Dr. Kinnicutt gave an account of some experiments which he had undertaken with Mr. F. G. Short on the quantitative determination of calcium. Calcium oxalate is precipitated highly crystalline from a boiling solution if it is cooled rapidly, and it may be filtered immediately. In the separation of calcium and magnesium, the calcium oxalate may be filtered without standing, if the formation of an ammonio-magnesium oxalate is prevented by using a small excess of ammonium chloride and by cooling rapidly after precipitation. (Ibid.) [306 Estimation of sulphur in illuminating-gas. — A method proposed by O. Knublauch consists in burning a known volume of the gas, mixed with air, in a glass tube, and absorbing the sulphuric and sulphurous acids in a solution of potassium carbonate. After oxidation of the sulphurous acid with potassium permanganate, the sulphur is calculated from the weight of barium sulphate obtained by precipitation with barium chloride. For details of the method, and description of the apparatus, reference is made to the original article. — (Zeitschr. anal. chem., 1882; also Berichte deutsch. chem. gesellsch., xv. 2403.) [307 C. F. M. Volumetric determination of copper, iron, and antimony by the processes of M. F. Weil. - If a standard solution of stannous chloride is added to a boiling solution of cupric chloride containing sufficient free hydrochloric acid to impart to it a yellow color, complete reduction of the copper solution is indicated by disappearance of the color. A solution of ferric chloride also is rapidly reduced by stannous chloride. In each case the final re-action is so clearly marked that no other indicator is required. When cupric chloride is added to a solution of antimonic chloride in an excess of hydrochloric acid, the mixture acquires a greenish-yellow color. If the quantity of copper is known, by deducting from the volume of tin solution required to reduce the mixture the volume corresponding to the copper, the difference represents the volume of stannous chloride required to reduce the antimonic to antimonious chloride. Copper, iron, and antimony may be determined in the same solution by a combination of these methods. After each series of determinations the tin solution must be restandardized. — (Revue des mines, Chem. news, 46, 284.) C. F. M. [308 AGRICULTURE. Availability of nitrogenous fertilizers. - To obtain an approximate idea of the relative value of different nitrogenous substances as fertilizers, Stutzer and Klinkenberg propose to digest them with an acid Fineness of superphosphates. In pot experiments with finely ground superphosphate and with the same substance artificially granulated, Wagner finds the former decidedly superior. — (Biedermann's central-blatt, 1882, 665.) H. P. A. [310 Clover sickness. A particular case of clover sickness' has been investigated by Kutzleb. It was shown that the failure of the clover was not due to parasites, to lack of nitrogen, to lack of water, or to unfavorable physical properties of the soil. An analysis of the soil showed a decided deficiency of easily soluble potash (soluble in carbonic-acid water), especially in the subsoil, in comparison with the soil of neighboring estates on which clover flourished; and the clover sickness is attributed by the author to this cause. No attempt appears to have been made to test the effect of manuring the field in question with potash. — (Biedermann's central-blatt, 1882, 728.) H. P. A. [311 Seed-testing. - Ad. Mayer and Van Pesch suggest various unimportant modifications in the methods of seed-testing in general use in the seed-control stations of Germany. Nobbe comments on these suggestions. A subsequent paper by Nobbe treats of the method to be followed in testing the sprouting power of beet-seed, and of the best manner of expressing the results. (Landw. versuchs-stat., xxviii. 167, 283.) H. P. A. [312 IGEOLOGY. Induration of rocks by atmospheric action. — Dr. M. E. Wadsworth gave some observations, made in 1871-73, upon the effect of atmospheric action in indurating the friable St. Peters and Potsdam sandstone in Wisconsin. This effect was quite strongly marked upon the exposed surfaces, resulting in induration, the partial obliteration of the granular structure, the formation of concretions, and even of quartz crystals; while the covered portions of the same blocks and slabs retained the usual friable character. (Bost. soc. nat. hist.; meeting Feb. 7.) - [313 Glacial phenomena of Mill Rock near New Haven.-Prof. W. P. Blake spoke of the low eastand-west ridge just north of New Haven, and referred its existence to the intrusion of trap-rock in the form of a narrow vertical dike, a part of the East-rock dike. It presents a precipitous front to the south; but northwards the slope is gentle, and is formed of sandstone. This dike of hard trap, and the adjacent hardened sandstone, stood up like a wall in the path of the great glacier; and its surface is strongly rounded off, grooved, polished, and striated by the ice. This cutting is best seen on the surface of the hard sandstone. The direction of the glacier appears to have been from the north-east. In addition to the glacial scratches, there is a series of transverse valleys or depressions having about the same direction. These appear to have been formed by the ice following the lines of outcrop of the harder beds of sandstone underlaid by soft red shales. Heavy bowlders of hard trap are irregularly distributed in sandy gravel on the north slope. There are some large bowlders of quartz, but granite bowlders do not occur. Most of the bowlders have flattened sides, showing extensive abrasion. They are generally ellipsoidal in form, and are often broken at one end. The quartz bowlders are found in forms which indicate that they were firmly held in the ice, first in one position, then in another, some of the smaller masses having several facets. A great variety in the nature of the soil is observed. There are deposits of clean sand and of bowlder-clay. These peculiarities, and the abraded bowlders, indicate the moraine profonde, or under-moraine. The large pot-holes cleanly cut in the sandstone of the north slope are referred by Prof. Blake to glacial origin, being similar to the giants' kettles' of the glaciated regions of Norway, and formed, probably, by vertical torrents falling through the ice-sheet. (Conn. acad. arts and sc., meeting Jan. 17.) [314 Humite. As the result of the crystallographic study of this mineral from Ludugrufvan (Sweden), Hj. Sjörgren has shown its analogy to the crystallized humite from Vesuvius, though the number of occurring planes is much smaller. The associations of the mineral from this locality is very similar to that occurring at Brewsters, N.Y.; the humite, associated with magnetite, calcite, and brucite, occurring from pure, through all stages of decomposition into serpentine. The pure, unaltered crystals were mostly found imbedded in calcite. In thin sections under the microscope, the appearance is almost identical with that of olivine. The author entering into a discussion of the chemical composition of this, and the closely allied minerals clinohumite and chondrodite, states that the presence of water in all these minerals has often been noted; and, although it fails to appear in most of the published analyses, there is, in most cases, a deficiency of constituents given, in order to make up the full 100 per cent; and this deficiency increases as the quantity of fluorine decreases. Provided this deficiency is due to undetermined water, it might be taken to indicate, that, where there is a deficiency of fluorine, a univalent hydroxyl group enters into the mineral as an isomorphous replacement of a part of the fluorine. Taking this into consideration, and also the varying ratios of Si: R (R=Mg and Fe), he finds that the three minerals agree closely with the following formulae, arranged so as to show their relation to one another and to olivine: olivine, Alloclasile.-This mineral, which occurs at Oravicza (Hungary) in small crystals resembling mispickle, has been newly investigated by A. Frenzel, and shown to be in composition also closely related. On account of the rarity of the crystals, enough of them could not be obtained for analysis; but several analyses from specimens of massive material were made which agreed nearly with the formula (Co Fe) (AsBi) S. It varies from mispickle in that most of the iron has been replaced by cobalt, and part of the arsenic by bismuth. - (Min. und petr. mitth., v. 179.) [319 8. L. P. METEOROLOGY. Thermal belts of North Carolina. - Professor J. W. Chickering read a paper on this topic, reciting the observations of Mr. Silas McDowell and others. The valley of the Little Tennessee river, in Macon county, is about 2,000 feet above tide. When the thermometer indicates a temperature of about 26° F., the frost extends about 300 feet in vertical height up the mountain-sides, and there ceases, appearing again 400 feet higher. In the intervening belt, the most delicate plants remain untouched; and so sharp are the dividing-lines, that sometimes one half of a shrub may be frost-killed, while the other is unaffected. Following a tributary stream upward from the valley, one passes three mountain-barriers, and enters in succession three valleys, the highest of which is plateau-like, and 3,900 feet in altitude. The vernal zone appears in each valley, rising as the valleys rise, but somewhat less rapidly; so that in the highest it is only 100 feet above the plateau. In this frostless zone the Isabella grape not merely has ripened for twenty-six consecutive years, but is free from mildew, blight, and rust. In Polk county a similar belt is said to skirt the Tryon mountain, extending from 1,200 to 2,200 feet above tide. This is untouched by frost until the latter part of December, and is usually free from snow; while the mountains above and the valleys below are covered. The peculiar stratification of the air indicated by these statements merits scientific investigation. — (Phil. soc. Washington; meeting Feb. 24.) [320 GEOGRAPHY. (Asia.) -- Riebeck in India. - Dr. Riebeck writes, that after returning with rich collections from Darjiling to Calcutta, where an industrial exhibition gave him opportunity to procure many specimens, he went to Chittagong, and secured in a relatively short time tribes. A famine in the hill country had driven the photographs and suffering people into the British territory, not with any warlike designs as had been reported, but simply to obtain food, mostly rice from the government stores. The poor people often came from twenty-five days' journey beyond the British boundary, and many of them had never seen Europeans before. — (Verh. gesell. erdk. Berlin, ix. 1882, 504.) W. M. D. [321 Regel in central Asia. - Dr. Regel reports a number of new geographic details to the Russian geographical society from the region of Karategin and Darwas, about the sources of the Amee River. The climate is clear and dry in summer; but in the long winter there are heavy snowfalls, preventing communication between the villages. On the way eastward to Karategin, he crossed three nearly meridianal mountain ranges. South-east of the Wakish, the ranges run north-east and south-west; and after crossing the Pandj (Pandsch), the great Badakshan range is fully parallel to the Hindu-Kush. The Wakish, Pandj, and Wandj rivers are respectively 100, 100-170, and 60-100 metres broad. The natives regard the latter two as the true head-waters of the Amee. They both have turbid water, and in winter carry cakes of ice. There are no bridges over the Pandj, and the stream is crossed on goat-skin floats. The population of these villages is very mixed: some of the tribes seem of true Aryan type. For the last fifty years the country has been desolated by wars, in which the prisoners were carried off to be sold as slaves at Buchara, Kashgar, and Badakshan. — (Verh. ges. erdk. Berlin, ix. 1882, 505.) W. M. D. [322 (Africa.) New expeditions for eastern Africa. — The geographical society of London has given Mr. Joseph Thomson command of an expedition to enter eastern Africa from Zanzibar, with the object of exploring a direct route to the eastern shores of Victoria Nyanza, and examining Mount Kenia. Thomson left England on Dec. 13. He has previously led two expeditions in this region with excellent success, and a good share of scientific results. He is now preceded in the field by Dr. G. A. Fischer, for whose expedition the Hamburg geographical society has appropriated 15,200 marks. Fischer was to leave Pangani last November, and march toward Liconono, then to the south-eastern shore of Victoria Nyanza, and the little-known Baringo Lake, and, if possible, to go on farther north. Parts of this region have been specially studied by German explorers: Erhardt, Krapf, and Rebmann, in 1848-49; v. d. Decken, Kersten, and Brenner, in 1859 and 1862; Hildebrand, in 187577; and Denhardt, and Fischer himself, in 1878. (Proc. roy. geog. soc., 1883, 32; Verh. ges. erdk. Berl., 1882, 399; Ausland, 1882, 978.) W. M. D. [323 Dr. Junker on the Uelle. This persevering explorer joined an armed Egyptian party a year ago, and followed down the valley of the Uelle, gaining some information about its probable lower course, and returning by a détour to the south and east. It seems that Uelle is simply, as is so often the case, the local word for river, and that its name is really Makua; so with its southern branch marked Nomayo on Schweinfurth's map, which should be Bomok indi. Dr. Junker concludes from native information, that the Makua Uelle is the head stream of the Shari; and that the Nepoko, rising farther east and flowing south, is Stanley's Aruwimi branch of the Kongo. He also refers to a large lake south of the region he passed through, and doubtless corresponding to the lake reported from upper Egypt by Lupton; Junker's Makua being presumably the same as Lupton's Bahr el Makwar. (Proc. roy. geogr. soc., Jan., 1883; Peterm. mittheil., 1882, 424, 441.) W. M. D. [324 BOTANY. The chromatophor of algae. While at the zoological station in Naples, Prof. Fr. Schmitz studied the arrangement of the coloring matter in the cells of marine algae; and he has since extended his observations to the coloring matter of other groups of plants. At present he gives only the results of his observations on algae, reserving for a future publication his researches on Archegoniata and phaeno gams. In a few plants, as the Phycochromaceae, the coloring matter is uniformly diffused through the cell; but in most cases it has a definite outline, and forms a mass to which Prof. Schmitz gives the name of chromatophor. In the higher plants the chromatophor is principally represented by chlorophyl grains; but in algae it is often represented by bands, stellate masses, or large irregularly shaped bodies. Schmitz finds in the chromatophors of many algae more or less spherical bodies to which he gives the name of pyrenoids. They occur in some red and brown algae, and are very common in green algae. Schmitz shows that the chromatophors of algae are capable of division, and that new chromatophors are always formed from some already existing chromatophor and not from the protoplasm itself, using the word in its strict sense. In some cases it appears to be the case that pyrenoids which are in reality nuclei of the chromatophors have been mistaken for the nucleus of the cell itself; as in the case of Anthoceras, where it has been generally supposed the cell nucleus was surrounded by an irregular mass of chlorophyl. (Verhandl. natur. vereins Rheinl. u. Westfalens, 1883.) [325 American Characeae. -The manuscript of the late Alexander Braun, of Berlin, has been edited by Nordstedt, who has added notes and observations of his own; and the whole forms the most complete monograph of the Characeae yet published. In it appear for the first time in print descriptions of several American species which were hitherto only known from herbarium names. The monograph includes one hundred and forty-two species and sub-species. — (Abhandl. acad. wiss. Berlin, 1882.) w. G. F. [326 W. G. F. -- Relations of organic matters in the soil to the process of assimilation in the sugar-beet. - The old experiments have been repeated and extended by Corenwinder, but have added very little to what was known before. He states, however, that the beet, when cultivated in a soil very rich in carbonaceous matters, can absorb more or less carbon from that As to the use which is made of this carbon, he is unable yet to express a positive opinion; so the question has not been materially affected by his present work. (Comptes rendus, Jan. 2.) G. L. G. 1328 source. Detection of adulterations in tea. Mayer calls attention to the peculiar character of the felted hairs on the leaves of certain Camellias, and to the universal occurrence of firm cells, which are almost true sclerenchyma, in the parenchyma of the under side of the leaves of tea. The cells are said to be best seen when thin sections of soaked leaves are first treated with dilute potassic hydrate, afterwards washed with alcohol of 50% which contains 10% hydrochloric acid, and finally placed in glycerine and water. — (Zeitschr. f. naturwiss., 1882, no. 3.), G. L. G. [329 (Fossil plants.) Laminarites Legrangei. Saporta reviews the characters and conformation of this species, described formerly by Saporta and Marion in their work on the Evolution of the vegetable kingdom, p. 101, f. 34. Nathorst of Stockholm had considered it as representing the tracks of animals. From better, very large specimens, Saporta has seen it composed of bands or |