20 Chemical Notices from Foreign Sources. centrated solution of chrome alum in vessels which are sealed at the lamp while boiling we observe that, however concentrated the solution, it does not, at common temperatures, deposit crystals of violet alum. Moreover, contrary to the assertions of M. Lecoq de Boisbaudran, it does not take the tint of solutions made in the cold, even after a very long time. These green solutions, preserved from contact with a crystal of alum and submitted to slow evaporation, whether by heat or in the dry vacuum of the air-pump, give as residue a solid, transparent matter, of an emerald green. This residue is the same, whatever may be the state of dilution of the original solution, and it preserves the same colour and appearance for more than a year. If instead of evaporation it is exposed to intense cold, crystals of alum are not produced. But a solution produced at the same temperature and not modified by heat yields when exposed to cold violet octahedral crystals of alum. If the vessels containing the green saturated solution are opened and the liquid touched with a crystal of chrome alum, a violet crystallisation begins and gradually increases. This effect may be produced by the contact, not merely of chrome-alum, but of any alum whatsoever. Those of potash, ammonia, iron, and thallium produce violet crystals, like chrome alum itself, contrary to the assertion of M. Lecoq de Boisbaudran. But the contact of crystals other than alums is unable to induce the crystallisation of the supersaturated solution. Transformatious of Persulpho-cyanogen.-M. J. Ponomareff. The author has studied the action of perchloride of phosphorus and of ammonia upon persulphocyanogen. Transmission and Inoculation of the Virus of Carbuncle, &c., by Flies.-M. J. P. Megnin.-The author finds it proved that certain blood-sucking flies with rigid and penetrating probosces, such as the Glossina (Tsetse flies), Simulia, &c., may effect the transmission of virulent maladies, and among others, of carbuncle. Reimann's Farber Zeitung, No. 43, 1874. This number contains remarks on the recent rise in the price of raw aniline and consequently of aniline colours; receipts for a cerise on woollen yarn; a marine blue on mixed woollen and cotton goods (both pieces and garments); and a fast black on cotton yarn. There is the continuation of a paper on the removal of "burls" from wool by chemical means. Böttger gives the following process for the manufacture of corallin. I part of crystalline oxalic acid, 1 parts of phenol, and 2 parts of oil of vitriol are heated for five to six hours to 140-150° C. The resulting mass is poured into hot water and boiled. There is thus obtained a resinoid product, brittle when cold, and with a green metallic surface reflection; when ground it yields an orangered powder. CHEMICAL NEWS, not merely nitro-benzol but also binitro benzol is formed, which by subsequently taking up hydrogen becomes phenylen-diamin. If the substance can be obtained in quantity, it may possibly serve for the preparation of phenyl-brown (Manchester brown), which has been already used in dyeing with success. 1 Daudenart and Verbert patent a process for utilising the waste water from scouring wool. It is mixed with a solution of caustic baryta as long as a precipitate is formed. When this has settled the clear liquid is drawn off, evaporated to dryness, and the residue ignited, yielding a mixture of potash with a little chloride of calcium. (In England soda would be generally found in place of potash). The fatty acids are separated from the precipitate by means of hydrochloric acid, washed, and pressed. The solution of chloride of barium is mixed with hydrate of magnesia, and carbonic acid is passed into the mixture until all the baryta is precipitated. Finally the carbonate of baryta is re-converted into caustic baryta by ignition with charcoal. Prof. A. W. Hofmann has found phenylen-diamin (C12H5N2H3) in aniline oils boiling at high temperatures, i.e., between 270° and 300°. It is a solid, crystalline body, boiling at 280°. The crystals melt at 63°. It was formerly made directly from binitro-benzol. Its occurrence in the above mentioned aniline oils is explained by the circumstance that in nitroising artificial impure benzol No. 44, 1874. This number contains receipts for a marine blue on woollen pieces, garments, or yarns; for a deep aniline blue on mixed woollen and cotton garments; and a yellowish mode on mixed stuffs and garments. An adventurer is going about Germany selling receipts for a "new brilliant black" and a "cheap brown." The former is produced by boiling the goods with lead-ore and soda, and the latter with truffles (1) 20 to 30 lbs. of which suffice for 100 lbs. of cloth. Then follows a receipt for a Guernsey blue on woollen yarn and for preparing trame silk. No. 45, 1874. The editor points out that soluble glass "free from amorphous silica" is being offered to dyers as a particularly valuable article. There are receipts for a blond, a light olive, and a stonegrey on wool; a coffee-colour on woollen yarn; an aniline violet on wool and cotton rags; an olive and a reseda on wool and cotton garments; a peacock-blue on cotton yarn, and a white on silk. For printing a Prussian blue Scheurer dissolves the colour in alkaline tartrate of ammonia. 50 parts tartaric acid, 190 ammonia, and 110 dry powdered Prussian blue, are dissolved together in 150 parts of water and thickened with an equal weight of tragacanth mucilage. The goods are printed with this mixture, dried, and passed through sours, which developes the colour. For dyeing the goods are steeped in the liquid-without thickeningdried and soured. The colour is very fast. Moniteur Scientifique, du Dr. Quesneville, Formation of Molasses.-F. Anthon.-Chemists are not agreed on the origin of molasses. Some maintain that its formation is due to non-crystalline organic bodies, gums, extractive, &c. Others hold that it is produced by the presence of mineral salts in the saccharine juice. Lastly, a third party believe that the substances "other than sugar may be classified as (a) generators of molasses; (b) indifferent; and (c) preventers of molasses. The author shows that chloride of calcium, added in small quantities, decreases the yield of molasses. But if added in large excess it prevents altogether the crystallisation of sugar, and the whole mass becomes molasses. Hence one and the same body may be either regarded as promotive or preventive of the formation of molasses, and the above classification must fall to the ground. Preparation of Saffranin.-A. Ott.-The author recommends as the best method to treat with syrupy arsenic acid the azotised compounds obtained by acting with nitrous acid upon heavy aniline oils containing toluydin, and boiling at 198° to 200°. For the preparation of the nitrous acid he takes I part of starch and 8 of nitric acid, heating in the water-bath; the gas generated before being conducted into the aniline oil is not washed in water, but passed through sulphuric acid. When the aniline has become a maroon-brown, and crystallises on a watch-glass, 100 parts are mixed with 90 parts of arsenic acid at 72 per cent. To prevent a too rapid rise of temperature the arsenic acid is introduced very gradually. The mass is then heated on the sand-bath till a violet colouration appears. According to Reimann (Farber Zeitung, No. 41, 1871) the application of heat for five minutes is sufficient. The author finds that in operating upon 50 grms. it is necessary to heat for at least two hours. The whole is then boiled with water containing lime, in which the violet colouring matter is insoluble. To remove the deposit formed the whole is poured upon flannel filters, beneath which is a layer of sand. The filtrate is slightly saturated with hydrochloric acid, and an excess of chloride of sodium is added. The precipitated saffranin is purified by solution in acidulated water, and re-precipitation with salt. boiling at 2055° to 209; this was benzoic alcohol, its boiling-point being raised by a trace of unaltered benzamide held in solution. Action of Sulphur on Carbonate of Lime.-Egidio Polacci.-With reference to his former paper on this subject (Gaz. Chim., t. iv., p. 245), that a mixture of flowers of sulphur, distilled water, and carbonate of lime gives, in two to three hours, an intense reaction of sulphuric acid. Production of Ozone by means of Electric Dis Gazzetta Chimica Italiana, Anno iv., Fascicolo 6, 7, and charges.-C. Giametti and A. Volta.-Not adapted for 8, 1874. Isomerism of Aromatic Bodies with Six Atoms of Carbon.-W. Koemer.-A paper occupying nearly 150 pages, and incapable of being usefully abstracted. Action of Hydriodic Acid on Santonic Acid.-S. Cannizaro and D. Amato.-A preliminary notice.-The direct product of the action is a hydrocarbon of the composition C15H24. On Meta-Santonin.-S. Cannizaro and D. Amato.Meta-santonin has the melting-point 160.5°. It is not affected by the action of the air or of light; it forms prismatic crystals, and under a pressure equal to 10 m.m. of mercury it melts at 238° to 240°. It is tolerably soluble in hot, but sparingly soluble in cold water; very soluble in ether and alcohol; most soluble in an aqueous acid solution formed by the action of water upon the iodide of phosphorus. Solution of potassa does not seem to have any effect upon it. abstraction. This number contains a report on the effects of bruising oats for the food of horses, which, contrary to expectation, Quantitative Determination of the Atomic Group proved injurious rather than beneficial, the animals fed on C2H2O contained in Acetyl Substitution-Products-ground oats being much more liable to sweat. The pro-Fausto Sestini.-A known quantity of the acetylic de- cess of M. Dobelle, of Amiens, however, who merely rivative is placed in a suitably-arranged recipient with a flattens instead of grinding, is stated to give satisfactory measured volume of normal solution of caustic soda, and results. is heated to 100° for some hours. Into the cold liquid is poured a volume of normal solution of sulphuric acid exactly equal to that of the alkaline solution employed. It is then filtered, the vessel and filter are well washed, and with the standard solution of soda the quantity of acetic acid produced by the reaction is determined. Action of Bromine upon Anhydrous Chloral.-A. Ogliaforo. The author expected to obtain the compound C2Cl, Br, or a chloro-bromide of the constitution C2C13Br3, by treating, first chloral with bromine, and then making the pentachloride or chlorobromide of phosphorus act upon the compound C2C13BrO, which, according to every probability, should be formed. The action of bromine upon chloral is much more complex. Allylate of Chloral.-A. Ogliaforo.-A preliminary notice. Transformation of Benzamide into Aldehyd and Benzoic Alcohol.-Prof. J. Guareschi.-The author added about 45 grms. of benzamide in a retort to ten to fifteen times its volume of ether, afterwards a little water, sodium amalgam, and pure and dilute hydrochloric acid. The reaction was sufficiently regular and care was taken that the liquid remained always acid, hydrochloric acid being added by degrees. To guard against a rise of temperature, the vessel was kept constantly in cold water. About 1500 grms. of sodium amalgam were employed, containing 3 per cent of sodium. When the reaction was over, the ethereal liquid was separated; it was faintly yellowish, and had an odour of bitter almonds. This liquid, distilled in the water-bath, left a residue liquid and yellowish, which had an intense odour of bitter almonds. It was agitated with 3 or 4 volumes of a solution of bisulphite of soda of sp. gr. 1'27, to separate benzoic aldehyd. The aqueous liquid, separated and decomposed with carbonate of soda, contained a small quantity of benzoic aldehyd. Having washed two or three times with water the liquid which had not combined with bisulphite of soda, it was submitted to distillation; a little water passed over first, then a portion boiling at 200° to 212°. On submitting this to fractional distillation, there was found a portion Reports on the Electro-catalytic Apparatus for Producing a Light, Invented by MM. Voisin and Dronier. This apparatus is based on the same principle as the Doebereiner lamp, but by the intervention of electric action the catalytic effect is reinforced. Mineral Industry at the Exhibition of Vienna, in 1873.-M. Gruner, a member of the International Jury.— A general view of the mineral statistics of the world. other Metals. An interesting paper which we may on a future occasion insert in full. Electrolytic Determination of Copper and certain No. 12, December, 1874. Kuhlmann, jun.-The Wigsnoes mine is situate in the Mines of Pyrites of Wigsnoes, Norway.-M. F. island of Karmo, on the west coast of the Scandinavian peninsula. It was discovered in 1865 by a French engineer, M. Defrance. The beds of pyrites are in contact with metamorphotic schist on one side, and on the other with gabro, known as hyperite and euphotide, composed of a granular mass of labradorite, white, green, and violet, strongly impregnated with smarage and diallage. It contains rock crystal, titaniferous iron, and garnets. The ore is generally composed of sulphuret of iron mixed with sulphuret of copper and furrowed with blende. The gangue is silica, with a little fluor spar and chlorite. Traces of carbonate of lime are also found. The average proportion of sulphur is 45 per cent, with 3 per cent of copper, though certain parts contain 12 to 14 per cent of that metal. Specimens of metallic copper are also found. Silver and gold occur only in very small quantities. Of arsenic there is not a trace, which greatly enhances the value of the ore for the manufacture of sulphuric acid. Les Mondes, Revue Hebdomadaire des Sciences. 22 Chemical Notices from Foreign Sources. charcoal with hydrochloric acid in the hope of increasing its decolourising power by removing the phosphate of lime is an error. He admits, however, that phosphate of lime has no action upon the colouring matter of madder. No. 13, November 23, 1874. Explosion at a Colour Manufactory.-On Wednesday, November 18, in the works of M. Poirier, manufacturer of aniline colours on a large scale, a retort containing nitrate of methyl, destined for the preparation of a new green, and heated to a high temperature under great pressure, burst suddenly with a report comparable to the discharge of several heavy cannons. Twelve of the workmen were severely wounded, two of whom are already dead, whilst twenty others sustained slighter injuries. The explosion was heard over all Paris, at Vincennes, Meudon, and St. Germain-en-Laye. The accident is ascribed to the imprudence of a workman, who, despite express prohibition, entered the shed with a lamp. Conditions of the Sugar Manufacture.-M. E. Pesier. Whatever may be the details and the name of the procedure adopted, it is indispensable to admit only the juice obtained by tearing and pressing the tissues; in other words, the liquor from the rasps and the presses and avoid the products of boiling the beet-root; consequently, to leave no pulp in the juice. This necessity has arisen {CHEMICAL NEWS, January 8, 1875. moving freely in all directions. According to this supposition, the calorific equivalent required to occasion, in a volume of gas v, a pressure =p, will be зри A being the equivalent of duty of the calorific unity. For a gas containing no other heat, the ratio k of specific heat to the pressure constant at that heat, the volume being constant will be . The maximum value found, in reality, is k=j, a close approximation. Clausius assumes, even in the chemical elements in a gaseous state, an internal atomic heat without influence or pressure. M. Puschl admits that a volume, v, of any fluid, submitted to a pressure, p, contains a caloric equivalent βυ A resulting from the condensations and rarefactions of its smallest elements of volume; and that although exciting locally differences of pressure and temperature, this equivalent influences neither pressure nor temperature in their totality. Taking this calorific equivalent into account, the minimum of heat which we can suppose in a gas is from the employment of filter-presses. To employ for and not defecation a dose of lime, so as to saturate the juice, To keep the defecated alkaline juice at a boil until the ammonia is completely expelled. The injection of steam or of carbonic acid, or mechanical agitation, promotes this object. Not to neutralise all the free lime with carbonic acid. To employ animal charcoal well burnt, well washed, and free from caustic lime, from sulphides, and from chloride of calcium. To avoid every stoppage, and even slowness in the operations. Finally, to evaporate as rapidly as practicable at the lowest possible temperature. No. 14, December 3, 1874. M. Chevreul has given in his resignation as Director of the Museum of Natural History. Classification and Purification of Saccharine Juices by means of Baryta and Basic Phosphate of Ammonia. The baryta is introduced in proportions suitable to combine with the mineral and organic acids present, and eliminate them by precipitation. Basic phosphate of lime is then added to the extent of 1 to 2 litres at 10° B. for each kilo. of baryta employed, and precipitates the lime. The application of heat expels the ammonia. Excess of the reagents must be avoided. These chemicals are much superior to blood and animal charcoal, the former of which introduces the germs of fermentation. Tanning with Chloride of Zinc.-MM. Meutens and Kresser propose to employ chloride of zinc in tanning hides, and in preparing a size for paper, incapable of putrefaction, and very slightly hygroscopic. 5pv 3pv as generally supposed; k, therefore, = 3. Electricity.-Professor Bolchmann has verified a series of formulæ relative to experiments on dielectric action at a distance, as also the dielectric constant of sulphur according to the difference of directions in reference to the optic axes in which the electricity acts. This constant, in fact, differs according to these directions, and in conformity with the theory of Maxwell, if we admit that the luminous take place normally in the plane of polarisation. The author has also determined the dielectric constant of glass, quartz, calc- and fluor- spars, and of selenium, both for permanent and alternating charges. No. 15, December 10, 1874. This number contains no chemical matter. Revue Universelle des Mines, de la Metallurgie, des This number contains no chemical papers, except such as have already been noticed in the CHEMICAL NEWS from their original sources: MEETINGS FOR THE WEEK. Medical, 8. TUESDAY, 12th.-Civil Engineers, 8. Photographic, 8. Anthropological, 8. New Process for Converting Sulphate of Soda.- MONDAY, Jan. 11th.-Royal Geographical, 81. Carbon has the property of converting sulphate of soda into silicate in presence of silica, sulphurous acid and sulphnr being given off. The process is conducted at a red-heat in retorts like those used for coal-gas, and heated in a similar manner. The sulphur is collected by condensation. The sulphurous acid may either be converted into sulphuric acid in the usual manner, or else it may be absorbed in carbonate of soda, yielding bisulphite of soda, which, when treated with zinc, yields the "hydrosulphite" now used in indigo dyeing. Alcoholic Yeast. This substance when dried can endure for some hours a temperature of 100°, and for a shorter time even 130°. In its normal state, containing water, it can endure cold amounting to -113° without becoming disorganised. Royal Institution, 3. E. Ray Lankester, Esq., M.A., WEDNESDAY, Chemical, 8. Royal Society Club, 61. London Institution, 7. Royal Institution, 3. Prof. P. M. Duncan, F.R.S., FRIDAY, 15th.-Royal Institution, 9. Prof. Tyndall, D.C.L., LL.D., TO CORRESPONDENTS. F. H. Storer, W. E. A. Aikin, J. Fallon, H, C. Bolton.-Received Theory of Gases.-Professor Puschl.-It is customary to ascribe the pressure of gases to the shock of their atoms with thanks. THE CHEMICAL NEWS. VOL. XXXI. No. 790. ON ATTRACTION AND REPULSION RESULTING FROM RADIATION.* By WILLIAM CROOKES, F.R.S., &c. (Continued from page 13.) 32. WHEN the balance was in air of ordinary density, and the hot body was placed above the pith ball in the position a (see fig. 2), it will be remembered that the action was to cause the ball to rise: the rising was, however, less decided than when the heat was applied below (27, 29). On re-exhausting the balance-tube and taking a series of observations, placing the hot bulb above the pith ball in the position a (fig. 2); instead of below it, the ascending tendency of the pith got less and less. Several millimetres below the previously ascertained point of neutrality the hot bulb at a ceased to exert an action, and marked, being exactly opposite but equal to the action of the bulb of hot water. 34. In trying some of these experiments in a Sprengel vacuum an action was noticed which led me to think that some of these movements might be due to electricity. When a hot glass rod is held motionless against the lower side of the exhausted tube, the repulsion of the pith ball takes place in a perfectly regular manner; but if the glass rod has been passed once or twice through the fingers, or if it is rubbed a few times sideways along the exhausted tube, the beam immediately moves about in a very irregular manner, sometimes being repelled from and at others attracted to the side of the tube, where it sticks until the electrical excitement subsides. When the finger is rubbed against the exhausted glass tube, the same electrical interference takes place; attractions and repulsions occur by fits and starts, the pith sticks to the tube, and does not regain its ordinary state for some hours. When a small spirit-flame is passed beneath the pith end of the balance in the vacuum, a similar but much fainter electrical effect is noticed. This, however, is not sufficient to interfere with the repulsion due to radiation unless the vacuum is very good and free from aqueous vapour. 35. The end of a glass beam in a Sprengel vacuum was found to be attracted by either pole of an inductioncoil, when the other pole was not well insulated. FIG. 4. when the neutral point was exceeded by some millimetres I could still detect no movement. However, at 2 millims. below a vacuum, I detected a tendency of the pith to sink when the experiment was tried, and in a good Sprengel vacuum there was an unmistakable repulsion exerted between the two bodies, the pith sinking in obedience to the radiation from above almost as strongly as it rose when the heat was applied beneath. 33. I now wish to ascertain the effect of cold on the balance pith balls, and for this purpose a lump of ice was employed. The experiments were first tried with the balance-tube full of air, cold being applied either above or below the pith ball; a lump of ice generally produced an upward movement of the pith, but it was very faint, and sometimes the motion appeared to be in the opposite direction. It was evident that the true action of a cold body, whatever it might be, was here masked by currents of air; and I therefore exhausted the apparatus and tried the effect of ice at the previously ascertained neutral point, viz., at about 7 millims. below the vacuum. It was absolutely inert. I then carried the exhaustion to the fullest extent, testing the balance with ice during its progress. As the gauge approached nearer and nearer to the height of the barometer, the ice commenced to attract the pith; and at last, when the gauge and barometer were level, the attraction of the ice, whether applied above or below, was very From the Philosophical Transactions of the Royal Society of London, vol. clxiv., par 2. Scale.. To ascertain whether electricity exerted any special action in the ordinary repulsions in vacuum, the following experiments were tried : 36. A straw beam with pith extremities was enclosed in a tube (24) and exhausted to the full power of the Sprengel pump. After adjustment by heat, till it was in equilibrium and very delicate to slight radiation, it was re-exhausted and hermetically sealed up. The tube was then completely surrounded with wet blotting-paper, with the exception of a small aperture through which the movement of the beam could be observed; the blotting-paper was connected to earth by a wire soldered on to a gas-pipe. On bringing a piece of warm copper beneath the pith ball, it rose as readily as if the outside of the tube had been dry and insulated. The finger moistened with warm water also repelled the pith; and when cooled with melting ice, and then applied dripping wet either above or below the pith ball, there was attraction. The same result, but more strongly marked, took place when a piece of ice was used instead of the cold finger. A straw beam furnished with brass balls at each end was suspended in the usual manner on a double-pointed needle; and the brass balls and needle were placed in metallic connexion by means of a very fine platinum wire. The needle did not rest on the sides of the glass * Preliminary experiments showed me that the brass balls on th straw beam acted in every respect the same as the pith balls, wit regard to hot and cold bodies externally applied, both at ordinar pressures and in a vacuum; but they moved in a more sluggis manner. tube but in steel cups, to which was soldered a platinum wire passing through the glass tube and connected to earth. The tube was then exhausted, and the usual experiments tried with hot and cold bodies, both with and without a wet blotting-paper cover. In all cases the brass balls behaved normally, being repelled by heat and attracted by cold. These experiments show that electricity is not a chief agent in these attractions and repulsions, however much it may sometimes interfere with and complicate the phenomena. 37. I now wished to see the effect of applying to the gravitating masses a hot body inside the exhausted balance-tube instead of outside, and accordingly constructed an apparatus shown in fig. 4. a, b are two balls suspended on a straw beam; c is a platinum spiral fastened to two stout copper wires cemented into holes drilled through a plate of glass, which can be cemented to the end of the tube; d, d are the battery-wires: e is the extremity of the tube, drawn out for attachment to the Sprengel pump. A single Grove's cell served to heat the platinum spiral to redness. By careful management and turning the tube round the necessary degree, I could place the equipoised brass ball either over, under, or at the side of the source of heat. A contact-key enabled me to heat the spiral without removing the eye from the micrometer. With this apparatus I wished to learn more about the behaviour of the balance during the progress of the exhaustion, both below and above the point of no action, and also to ascertain the pressure corresponding with this critical point. In air of ordinary density the action of the hot spiral was one of attraction both above and below. Not wishing, however, to complicate the action by air-currents, I exhausted with the Sprengel pump until the gauge stood about millims. below the barometer. I then tried the 40 following experiments: 38. The brass ball was placed so that its position when in equilibrium was about 1 millim. above the spiral, and The ball was the latter was rendered incandescent. immediately drawn down to the spiral, sometimes touching and then rebounding with considerable force. 39. The brass ball was then arranged so that it was about 1 millim. below the spiral. On turning on the battery-current the ball rose to the hot platinum. This latter action might be due to air-currents; but it is difficult to imagine that air-currents could drag the ball down to the hot spiral when the latter was beneath it (38). 40. The ball was arranged so that the platinum spiral was opposite the end, but a little above, as shown in fig. 4A. On igniting the spiral the movement was very slightly upwards. When the spiral was rather below the ball, as shown in fig. 4B, the ball moved downwards when contact with the battery was made; the tendency in each of these cases was to bring the centre of gravity of the brass ball as near as possible to the source of heat. 41. The pump was then worked until the gauge had risen to 5 millims. of the barometric height. On arranging the ball above the spiral and making contact, the attraction was still strong, drawing the ball downwards a distance of 2 millims. The pump continuing to work, the gauge rose until it was within 1 millim. of the barometer. The attraction of the hot spiral for the ball was still evident, drawing it down when placed below it, and up when placed above it. The movement was, however, much less decided than before, and in spite of previous experience (30, 31) the inference was very strong that the attraction would gradually diminish until the vacuum was absolute, and that then, and not till then, the neutral point would be reached. Within 1 millim. of a Sprengel vacuum there appeared to be no room for a change of sign. 42. The gauge rose until there was only half a millimetre between it and the barometer. The metallic hammering heard when the raefaction is close upon a vacuum commenced, and the falling mercury only occa CHEMICAL NEWS, sionally took down a bubble of air. On turning on the battery-current, there was the faintest possible movement of the brass ball in the direction of attraction. 43. The working of the pump was continued. On next making contact with the battery, no movement of the ball could be detected. The red-hot spiral neither attracted nor repelled. I had arrived at the critical point. On looking at the gauge I saw it was level with the barometer. (To be continued.) LECTURES ON THE MORPHOLOGY OF AT THE CHEMICAL SOCIETY. By NEVIL STORY MASKELYNE, M.A., F.R.S., &c. LECTURE III. HAVING thus far treated of some of the simplest relations of crystal faces as referred to a system of axes crossing one another at right angles, the lecturer proceeded to indicate the methods by which such relations may be also established between the faces where either no axes perpendicular to each other are furnished by edges of the crystal, or where, for other reasons, axes oblique to each other are selected. And, first, he pointed out the general features of a crystallographic axial system. Such a system will present, in its most general form, three axes, X, Y, Z, inclined to one another, at angles represent two quantities, viz., and, which will give the ratios of the intercepts of some assumed plane, viz., on the axis of X, I on the axis of Y, and on the axis of Z; hence, such a system presents five elements, viz.: a C It will also be observed that the space around the origin of the axes is divided by the three axial planes, XY, Fig. 3. YZ, ZX, into eight spaces, or compartments, termed octants, which may be characterised by the signs of the axes that include them. |