^B! »w.n-.>. ->it0 * . 496 On the Aurora Borealis of the 7th of January, 1831. By Dr. MOLL, of Utrecht . "v * . . . . .519 Observations on the Aurora Borealis of the 7th of January, the llth of January, and the 7th of March, 1 83 1 . By the Hon. CHARLES HARRIS ........ 522 On the Height above the Surface of the Earth of a Luminous Arch of the Aurora Borealis, on the 7th of January, 1831. ByS. H. CHRISTIE, Esq., M.A., F.R.S., &c. . . . .525 On Elaterium ; and a New Principle obtained from it by Analysis. By HENRY HENNELL, F.R.S., M.R.I., Chemical Operator, Apothecaries' Hall • /«;. . . ^ * .••••) . . 532 Contributions to the Physiology of Vision. No. II. . . 534 On the Ripple-Marks and Tracks of certain Animals in the Forest Marble. By G. POULETT SCROPE, Esq., F.R.S., F.G.S., &c. . 538 11 CONTENTS. Page Proceedings of the Royal Institution of Great Britain . .547 Proceedings of the Academy of Sciences in Paris . . .558 ANALYSIS OF BOOKS, AND SELECTIONS FROM THE TRANSACTIONS OF SCIENTIFIC SOCIETIES. Life of Sir Humphry Davy, Bart., LL.D. . . . .571 Acta Academiae Caes. Leop. Carol. Naturae Curiosae Bonnae . 585 Memoirs of the Institute of France . . . .595 FOREIGN AND MISCELLANEOUS INTELLIGENCE, § 1. —MECHANICAL SCIENCE. 1. Stiffness and Strength of Timber .... 599 2. Proportion between the Metre and English Yard . . ibid. 3. On the Velocity of an Elastic Fluid which flows from a Reservoir into a Gasometer ...... ilrid. 4. On the Discharge of a Jet of Water under Water (R. W. Fox, Esq.) ibid. 5. Optical Deception upon the Liverpool and Manchester Rail Road 600 6. A Barometer of a new Construction (Proposed by M. Kupffer.) . 601 7. Occultation . . . . . . . ibid. 8. Pendulum Observations ...... 602 9. Dip of the Magnetic Needle at St. Petersburgh ... 604 10. On the Direction and Intensity of the Magnetic Force at St. Peters- burgh (M. Erman) ...... ibid. 11. Variation of the Needle ..... 607 12. On the Figure of the Magnetic Equator .... ibid. 13. New Dipping Needle ...... 608 14. Powerful Electro-Magnets . . . .609 15. On the Intensity of the Earth's Magnetism (Kupffer) . . 610 § II.— CHEMICAL SCIENCE. 1. Matteuci on the Origin of the Action of the Voltaic Pile . . 612 2. Conducting Powers of Liquified Gases (K. T. Kemp) . .613 3. Generation of Steam by Heated Metal . . . ibid. 4. On the Preparation of lodic Acid (Serullas) . . . 614 5. On the Precipitation of the Vegeto- Alkalies by lodic Acid (Serullas) 615 6. On the Action of Bromic and Chloric Acids on Alcohol (Serullas) ibid. 7. On Perchloric Acid and its Facil Formation (Serullas) . . 616 8. On the Spontaneous Inflammation of Pulverized Charcoal (Aubert) . 617 CONTENTS. ill Page 9. Power of Carbon to destroy the Bitterness of certain Bodies ••>-» 619 10. Method of preparing Selenium from the Sulphuret (M. Magnus) . 619 11. On the Compounds of Ammonia with Anhydrous Salts (H. Rose) 620 12. Test of the Protoxide and Peroxide of Iron (Berzelius) « ,. 624 13. A new Metal Vanadium, associated with Iron (Sefstrom) . ' , 625 14. Combustion of an Alloy of Tin and Lead (R. W. Fox) . . 626 15. Vauquelin's Process for obtaining Metallic Chromium ,•» • ^'^ 16. On the Absorption of Oxygen at High Temperatures, by Silver (Gay-Lussac) w { ; i . U*T^' »*>"' 627 17. Robiquet on a new Metallic Dye ..... 628 18. Purple Precipitate of Silver, Gold, &c. &c. ?"™' "*", »,., . ibid. 19. (Enometeror Alcohometer (M. Emile Tabarie) . , . 629 20. On the Manufacture of Sulphuric Ether (C. Wittstock) . ibid. 21. On Columbine ; a New Vegetable Principle (M. Wittstock) . 630 22. On the Composition of Camphor and Camphoric Acid (J. Liebig) 631 23. Use of Mica in minute Chemical Analyses . . 633 24. On Perforating and Cutting Glass, Earthenware, &c. (Mr. Marsh) . ibid- § I II. —NATURAL HISTORY, &c. 1. Circulation of Fluids in Vegetables . . . .635 2. Structure of Leaves ...... 636 3. Germination of Seeds at the Surface of Mercury . ' i' • . 637 4. Fertilization of Plants . . ;ov '; . . ibid. 5. Structure of the Radish Root . fo*?^' . . . 638 6. Russet in Apples . . . *• y*- - . >/. 3* • Hid. 7. Medicinal Use and Effect of the Ava Root . i ' 3«jf*>-« ! &V" 639 8. Mexican Domestic Bees. (Melipona Beechei) . g»--t . 640 9. Mean Meteorological Results . . . . 641 10. Climate of England. ...... 642 11. On the Earthquake at Odessa on the 26th of November, 1829 (M.Hauy) . . . . #%> ., . 64a 12. Geography of Siberia .... ,.i*l..:.! ;..'.,. 644 ERRATA IN No. III. Page Line Pajrc Line 320 4 from bottom, for Chartres read 330 25 from top, for Tanz read Jansr. Castres. ib. 2 from bottom, for Tanz read Jansz. 325 5 from \witom, fur vitro-crystal lines 331 6 from top, for Borel rend Boreel. read vitrocnstallincs. 332 5 from top, for Borel read Boreel. 329 16 from top, for Bussi read Russii. ih. 1 from bottom, for that read thus. ib. 22 from top,/or Teannin read Jeannin. ib. 1 from bottom, for produced read pro- ib. 23 from top, for Busbi read Russi. cured. ROYAL INSTITUTION OF GREAT BRITAIN, 4lh April, 1831. THE WEEKLY EVENING MEETINGS of the Members of the Royal Institution will be resumed on Friday the 15th instant, at half-past Eight o' Clock, and will be continued on each succeeding Friday evening till the end of the Season. The following are the Arrangements of the Lectures which are to be delivered on each day at Three o' Clock in the Afternoon : — CHEMICAL AND NATURAL PHILOSOPHY. By MICHAEL FARADAY, Esq., F.R.S., F.G.S., Corr. Memb. Royal Acad. Sciences Paris, Director of the Laboratory of the Royal Institution, &c. &c. To commence on Thursday, the 1 4th instant, and to be continued on each succeeding Thursday till the 5th of May. The following are the Subjects of the Course : — April 14th, Optical Decep- tions— April 21st, Lithography — April 28th, Flowing of Sand— and May 5th, Caoutchouc. GEOLOGY. On some of the most important points in Geology. By THOMAS WEBSTER, Esq., F.G.S. To commence on Saturday, the 16th of April, and to be continued on each succeeding Saturday till the 21st of May. POETRY AND THE POETS. By JAMES MONTGOMERY, Esq., Author of ' The World before the Flood,' f Pelican Island,' &c. To commence on Tuesday, the 26th of April, and to be continued on each succeeding Tuesday till the com- pletion of the Course, on the 31st of May. ACOUSTICS. By ROBERT WILLIS, M.A., F.R.S., Fellow of Caius College, Cambridge. To commence on Thursday, the 12th of May, and to be continued on each succeeding Thursday till the completion of the Course, on the 1 6th of June. BOTANY. On Vegetable Physiology and Botany. By JOHN LINDLEY, Esq., F.R.S. and F.L.S., Prof, of Botany in the University of Lond., and Assist. Sec. Hort. Soc. To commence on Saturday, the 28th of May, and to be continued on each succeeding Saturday till the completion of the Course, on the 18th of June. The Sons and Daughters of the Members of the Royal Institution, under Fifteen Years of Age, may be admitted on payment of half the sum for each Course. Syllabuses of the Lectures may be obtained at the Royal Institution. JOURNAL THE ROYAL INSTITUTION OF GREAT BRITAIN. ON CERTAIN PHENOMENA RESULTING FROM THE ACTION OF MERCURY UPON DIFFERENT METALS. BY J. F. DANIELL, F.R.S., AND M.R.I. E results of the following experiments on the action of mercury upon different metals may probably be considered interesting; not only on account of the novelty of the facts, which have been hitherto, I believe, unnoticed, but from the relation in which some of them may be found to stand to the laws of molecular attraction. EXPERIMENT I. A piece of flexible metallic tube, which is composed of an alloy of tin and lead, was partly immersed in mercury con- tained in a wine-glass. In the course of a few days it was exa- mined, and found studded with brilliant metallic crystals, in a line coincident with the level of the fluid. After this exami- nation, it was replaced and left undisturbed for six weeks : at the expiration of which period it was carefully lifted out of the mercury ; and a considerable groupe of well-defined crystals were found loosely adherent to its upper part, and many similar ones floating upon the surface of the mercury. Their form was that of hexahedral plates variously modified ; some of them were above one-tenth of an inch diameter, and their lustre was white and silvery. By placing them in a small inverted cone of paper, perforated at its apex, the fluid mercury drained from VOL. I. OCT. 1830. B S Mr. Daniell on the Action of Mercury them, and they were left in nearly a dry state. The tube was dissolved away at its lower end to a thin edge, and the action of the mercury had evidently decreased as it ascended : the upper part to which the crystals were attached was but little acted upon, so that, in its whole length, it gradually tapered downwards. The substance of the metal, even above the part immersed, was saturated with mercury, and had become very brittle. Hence it appears that the action of the mercury upon the alloy was, first to saturate its pores and disintegrate its sub- stance, forming a brittle, uncrystallized compound which it must have subsequently dissolved. The amalgam thus pro- duced, being of less specific gravity than the fluid metal, floated to its surface, where the attraction of cohesion between the par- ticles of the compound, being greater than the attraction which held them in solution in the fluid, caused them to crystallize. I have formerly * remarked, that if a mass of any soluble salt be carefully suspended in water, it will be more acted upon at its upper than its lower end, and will assume, more or less, the form of a cone, with the apex at the surface of the liquid. The particles of water which are in immediate contact with the salt, combine with a portion of it, and thus becoming speci- fically heavier than the remainder, sink to the bottom of the vessel ; others succeed and follow the same course. A layer of saturated solution is thus deposited, which increases in depth as the process advances, protecting in its rise that part of the mass which is covered with it from further action. In the present instance the process is directly the reverse : the solvent, by union with the solid, becomes specifically lighter, and the saturated solution is first formed upon the surface ; and the action continuing longest at the bottom of the mass, a cone is produced with its apex downwards. EXPERIMENT IT. A piece of pure tin, in the usual form of closely- aggregated imperfect prisms, in which it is found in commerce, was partly immersed in mercury, and left undisturbed for a month. Upon * Journal of the Royal Institution, vol. i,, p. 24, 1st Series, upon different Metals. 3 examination, a large cluster of crystals, similar to the preceding, was found adhering to its upper part, and others floating upon the liquid. They were not quite so large as the first; but bore very distinctly the form of six-sided plates. The whole mass was thoroughly saturated with mercury, but had been more acted upon at the bottom than the top of the portion immersed. At the lower end, the prisms had the appearance of being more detached from one another than in their original state, from cracks which had taken place in the metal ; and which conferred upon their extremities the semblance of imper- fect pyramids. Several deep clefts also had been formed along the more prominent edges of the mass. EXPERIMENT III. A small bar of lead was plunged, for about half its length, into some mercury contained in a test-tube. Having been left undisturbed for ten days, it was carefully lifted out and exa- mined. A bundle of very delicate, silver- white, feathery crystals was found loosely adhering to it, on a line with the surface of the fluid. Their form could not be accurately determined, but they resembled a heap of frosty particles swept together on a pane of glass ; and their minute prisms appeared to be attached together at angles of sixty degrees. The bar had been most acted upon at its lowest extremity : it was thoroughly impreg- nated with mercury throughout its substance, but had not totally lost its ductility. After the operation, the tin crumbled to pieces under a slight blow of the hammer, but the lead could be flattened into a plate. EXPERIMENT IV. A bar of zinc was treated in the same way, and for a like period. It was found, upon examination, studded throughout the whole length which had been immersed with very bold crystals, of the form of hexahedral plates, which increased in quantity and size from below upwards. The bar tapered downwards to a point, and was more unequally acted upon than the former metals, its surface being rough, and corroded into cavities. Some of the crystals adhered very strongly to the surface, and B 2 4 Mr. Daniell on the Action of Mercury some of them had the appearance of being partly imbedded in the bar, or dissected from its substance. They were of a darker hue, and more brilliant than the crystals from lead and tin. EXPERIMENT V. A bar of fine silver was partly immersed in mercury, as in the preceding cases : at the expiration of a fortnight no crystals had been formed. The mercury had entered into its substance, but upon trial it had not lost its malleability. It was replaced, and at the end of six weeks had not apparently changed its characters. The test-tube, with its contents, was now heated till the mercury began to boil, and was set by to cool gradu- ally. In twenty-four hours' time the bar was again examined, and a bundle of very fine needle-crystals was found clustered round the part which was just intersected by the surface of the liquid. In this case, the affinity of the mercury for the silver enabled it to penetrate its pores, and thoroughly to saturate it, but its attraction for the resulting compound was not sufficiently strong to allow it to overcome the remaining attraction of aggregation, and dissolve the solid at the ordinary temperature of the air. When assisted, however, by heat, the solution was effected, and the compound, as in the former instances, being specifically lighter than the pure fluid, floated to the top, and crystallized. EXPERIMENT VI. A small portion of a bar of fine gold, about an inch and a half in length, was put into mercury, in which, of course, it sank, from its greater specific gravity. The fluid very quickly penetrated it, and completely destroyed its yellow colour. In a month's time it retained its malleability, and a part of it was flattened under the hammer into a very thin plate. Its sur- face was studded with very minute crystals, whose dimensions were too small to be determined. The gold was then heated in the mercury to the boiling point of the latter, when it was completely dissolved, and a pasty amalgam formed. There can be no doubt tlaat in all these instances the mer- upon different Metals. 5 cury formed definite solid compounds with the several metals, which were capable of being held in solution by an excess of the fluid ; but were also capable, in favourable circumstances, of separating from it, and crystallizing in peculiar forms. Whether, at the same time, any other compound may have been formed of an essentially liquid nature, I have not ex- amined; but I may here remark, that the manufacturers of looking-glasses have made the observation, that the mercury which is pressed out of the tin amalgam, which they apply to the backs of their plates, is in as pure a state as that which they originally make use of. EXPERIMENT VII. A square bar of tin, about five inches long, and whose sides were a quarter of an inch wide, was laid horizontally in a card- tray, and just covered with mercury. To render the action as equal as possible, it was frequently turned upon its different sides, and examined. At the expiration of twenty-four hours, minute fissures began to appear along all its lateral and termi- nal edges. The process was continued, and the cracks widened, until, on the third day, they opened to such a degree as to shew that the bar was resolved into four equal trihedral, rect- angular prisms, with two equal angles. They were readily separated from each other by the point of a penknife, and two similar pyramids, whose angles at their bases were 45°, were at the same time detached. This groupe is accurately represented in their relative positions, a little separated, at Fig. 1, Plate I. a, a, a, a are the small triangular prisms, which, when in contact, made up the original square bar ; and b represents one of the terminal pyramids. All the angles were as sharp and perfect, and the faces as neat, as if they had been carved with tools ; and when brought into contact with one another, they adhered together with some force, from the cohesive attraction of a little mercury which hung about them. This experiment I imme- diately repeated, and obtained the same very remarkable results. I was at first induced to consider this singular phenomenon as dependent upon the original structure of the bar, from the consideration of the following facts, which are well known to 6 Mr. Daniell on the Action of Mercury most workers in the metals, and which I have myself verified by experiment. No metal can be hammered round upon an anvil, either hot or cold. Blacksmiths very well know that they cannot forge a round bar of iron ; and I have myself seen a rod of the best iron which, properly heated, could be extended indefinitely, when hammered square or flat, split into fibres, and become perfectly disintegrated after a few blows given equally round. When it is desired to give a round form to any part of a square bar of iron, it is effected by forcing it, while hot, into a kind of fornij or mould, of the required dimensions ; or, as is well known, it may be extended in a cylindrical form to almost any degree, by the equal pressure applied in the process of wire- drawing. If square bars of gold, silver, or copper^ the most malleable of all the metals, be hammered upon the edges, and the blows repeated round, so as to give them a cylindrical shape, they soon become what is technically termed rotten, and break into fibres, while the bars may be extended under the hammer to any degree, by blows directed parallel to their ori- ginal faces, or may be beat into leaves of almost inconceivable thinness, if the force be directed upon one surface only. The less malleable metals, lead, brass, and tin, become even sooner disintegrated when hammered round ; and, although they are capable of considerable extension, when hammered square, they ultimately split along the edges in a manner very similar to the disintegration which I have just described as resulting from the action of mercury upon the tin bar. It is also worthy of observation, that the metallic bars, when hammered square, generally assume a rhomboidal, rather than a perfectly rectangular form, and that the fissures take place indifferently upon all the angles ; but if the hammering be continued, they sometimes split into two, in the direction of one of their diagonals, before the separation takes place in the direction of the other. I have not been able to satisfy myself whether this tendency to the rhomboidal form results from any inequality in the blow of the hammer, producing an inclination of the planes of compression to one another ; or whether it may be referred to the forms of the ultimate particles of the metals ; but I have ascertained that it takes place even when the greatest upon different Metals. 7 pains are taken to keep the face of the hammer parallel to the surface of the anvil ; and that it can only be counteracted, when required, by directing a blow from time to time upon the acute angle. To determine, if possible, whether any connexion sub- sists between these results of the direct application of mecha- nical force to the metals, and the structure of the bars of tin developed by the action of mercury, as just described, I insti- tuted the following experiments. EXPERIMENT VIII. A bar of tin, of about the same dimensions as the last, which had assumed the rhomboidal form during the process of ham- mering, from the original cylindrical shape in which it had been cast, was treated with mercury in the manner described above : it was resolved, as before, into four rectangular trihe- dral prisms, but with two unequal angles, corresponding to the bisected angles of the rhomboid. EXPERIMENT IX. The tin bars upon which the previous experiments were made had been shaped by the hammer, and I was desirous of ascer- taining whether the forces which had been applied had in any way disposed their particles to assume the structure which had thus been developed. For this purpose, a bar was cast, in a mould, of nearly the dimensions of that employed in Exp. vii. and was treated with mercury in the same manner. The four trihedral prisms, with their two pyramids, were formed as before ; but the clefts and the planes of junction were not as neat as in the foregoing instances. This seemed to be owing to the angles of the original bar not having been so sharp as when formed by the hammer, but having necessarily come rounder from the mould, and presenting a surface to the action of the mercury. EXPERIMENT X. A cast cylinder of. tin, five inches long, and a. quarter of an inch in diameter, was substituted for the square bar in the 8 Mr. Daniell on the Action of Mercury , experiment : at the end of three days, during which it was frequently turned, the terminal edges were cleft all round, and irregular cracks appeared upon various parts of its surface. Two solid pieces, approaching the hemispherical form, but much flatter, were extracted from the ends by the point of a knife, and two cup-like cavities were formed in the bar. By introducing the edge of the knife into the cracks upon the sur- face, its substance was broken away in parts, and a concentric arrangement of the amalgam disclosed round a central nucleus 5 the appearance of which is represented at Fig. £. The out- side coating, 6, 6, was perfectly brittle, but the centre rod, a, a, still partially retained its malleability, and could be bent two or three times backwards and forwards, before it broke. EXPERIMENT XI. Another bar of tin was cast, of the form and dimensions of half the preceding cylinder, divided longitudinally. Its ap- pearance, after being treated with mercury as described, is exhibited at Fig. 3. Its two lateral edges were sharply cleft asunder, as at a, a, and some irregular cracks appeared upon its round surface. Part of the substance of the amalgam was broken away, as shewn at bt when a centre cylindrical rod appeared, and the concentric arrangement was apparent, as in the last experiment. EXPERIMENT XII. Having cast a cylinder of tin, similar to that employed in Exp. x., one half of it was made square by the file, and the whole was then submitted to the action of mercury as before. The cleavage down the lateral edges, which were very sharp, was perfect, and a most beautiful pyramid was formed at the square end. The cylindrical portion of the bar was irregularly cracked, and there seemed to be a tendency of the clefts in the square edges to continue their course into this part. These results are represented at Fig. 4; a is the terminal pyramid, by b the cleft upon one of the edges of the square bar ; c, c the cylinder. upon different Metals. ' 9 EXPERIMENT XIII. I cast a square bar of tin, of similar dimensions to that which I employed in Exp. ix. One half of its length was hammered upon the edges till four new planes were formed in their places, and the square reversed from its original position. Thus both ends of the bar were still square, but the edges of one half were in the direction of the planes of the other half, and a small intermediate portion was irregularly octangular. The whole was soaked in the shallow bath of mercury. The cleavage upon the edges of the hammered half was perfect, and the trihedral prisms and terminal pyramid very distinct. The edges of the cast portion were not cleft, but the sharp divisions of the ham- mered edges were continued down its faces, in ragged, irregular cracks, which gaped particularly near the point of junction. This end, therefore, had a tendency to separate into four tetra- hedral prisms, and the force was so great, that they broke off near the point of junction of the two parts of the bar, and ultimately assumed the appearance represented at Fig. 5. The sharp and even cleft upon one of the edges of the hammered portion is exhibited at a, a, and the ragged crack upon the corresponding face of the cast part at b b, gaping at the point of fracture, c, c, as if rent asunder with great violence. I attempted in vain to produce analogous results with bars of lead, brass, gold, silver, and zinc, for in none of these in- stances could I obtain evidence of the action of any mechanical force acting upon the particles of the metals ; although their union with the mercury was, to all appearance, as intimate as that of tin. No cracks or disruptions appeared in any of them. The surfaces of the four first remained perfectly smooth and continuous, but that of the last was corroded into cavities. There can be little doubt, I think, that the disruptive force which effected the disintegration of the tin bars, in the manner above described, was the powerful contraction of the integrant particles of the metal, in the act of combining with the mercury. It has, indeed, been proved that the amalgam hence resulting is of considerably greater density than the mean of its compo- nent parts, and that such approximation of molecules must, 10 Mr. Daniell on the Action of Mercury therefore, take place ; the balance of force which determines its particular direction in the instances pointed out, forms an interesting subject of investigation, which, together with the cleavage and dissection of crystals, and the manner in which they are affected by light and heat, may ultimately contribute to the explanation of the laws of molecular attraction. I shall conclude this paper with the result of some experi- ments upon the mutual action of mercury and platinum. EXPERIMENT XIV. There is no apparent action whatever between mercury and a bar of platinum, at the common temperature of the atmos- phere ; but when exposed together for a short time to the boiling point of the former, the latter becomes superficially coated with the fluid. The combination is so slight, that the mercury may easily be wiped off mechanically, as water from wet glass. Platinum, which has been kept constantly wetted with mercury for six years, has not become disintegrated, or in any way changed its properties. EXPERIMENT XV. A few grains of spongy platinum, formed from the ammonio- muriate, were violently agitated with mercury and a few drops of water in a test-tube : a kind of thick scum, or semifluid amalgam, speedily collected upon the surface, from which the still fluid metal could easily be poured off. EXPERIMENT XVI. The foregoing experiment was repeated ; but the water was acidified with acetic acid. The test-tube was five inches long, and about half an inch diameter. The mercury occupied about an inch, and the weak solution of the acid about half an inch of its depth. The platinum was thrown in, and the whole shaken together for a short time ; when the tube became filled with an amalgam, of the consistence of soft butter. When the tube was upset, a very few drops of fluid mercury ran out of it ; and when the amalgam was shaken out into a saucer, it retained its consistence for many weeks. It possessed a dullish metallic hue, like that of lead which has become tarnished ; and very upon different Metals. H much resembled the amalgam formed by the electrization of mercury in contact with ammonia. The experiment was frequently repeated, sometimes with the substitution of some neutral salt for the acid, and always with similar results. When the amalgam was laid upon filtering paper, the mois- ture was gradually absorbed and evaporated, and the mercury returned to the fluid state. EXPERIMENT XVII. The experiment was varied by filling a tube, which was some inches longer, with the weak acid solution ; and after the formation of the amalgam by agitation, inverting it in a cup of mercury. Minute bubbles of gas were immediately seen rising from the amalgam through the fluid, and collecting in the upper part of the tube. Upon close examination, particles of the spongy platinum could be discovered between the sides of the glass and the mercurial paste, round which bubbles of gas gradually accumulated, which gave the whole a honey- combed appearance. These, as they increased in size, slowly crept up the sides of the tube, till, reaching the fluid, they rapidly ascended to the top. In twelve hours' time, nearly the whole of the liquid had been expelled from the tube, and when a light was applied to the gas it exploded. Some of the acetic solution, which had been frequently em- ployed in repetitions of the experiment, was slowly evaporated, and afforded crystals of prot-acetate of mercury. EXPERIMENT XVIII. I endeavoured, in vain, to produce analogous results, by agitating amalgam of gold and other amalgams with diluted acetic acid and solutions of neutral salts. No action was apparent, and in no instance was anything like the frothy amal- gam produced. Hence it appears that, when minutely divided platinum is agitated with mercury, and moisture is present, an electrical action takes place, which, when heightened by the addition of a diluted acid, or the solution of a neutral salt, is sufficiently energetic to decompose water and evolve hydrogen : the oxygen 12 Mr. Daniell on the Action of Mercury, fyc. at the same time combines with the mercury, and a solution is effected by the acetic acid, which its unassisted affinity could not have produced. This action appears to be of the same nature as that described by Mr. Faraday *, in his account of the Alloys of Steel ; during his experiments upon which, he found that steel, alloyed with an hundredth part of platinum, was acted upon by dilute sulphuric acid, with infinitely greater rapidity than the unalloyed steel, and that an acid, which scarcely touched the pure steel, dissolved the alloy with ener- getic effervescence. It also appears that this electrical action communicates an adhesive attraction to the particles of the metal, by which the particles of liquid and aeriform bodies are entangled and re- tained, a kind of frothy compound formed, and the fluidity of the mercury destroyed. The appearance of this amalgam is so very like that of the ammoniacal amalgam formed by ex- posing a solution of ammonia in contact with mercury to the influence of the Voltaic pile, or when an amalgam of potassium and mercury is placed upon moistened muriate of ammonia, that it is impossible not to be struck with the resemblance. I am inclined, indeed, to believe, that the production of the latter may be explained upon the same principles as that of the for- mer. When the effect is produced by the direct application of the electrical current, by means of the battery, it ceases the moment the connexion between the poles is broken ; and when brought about by the agency of the amalgam of potassium, the elec- trical action is doubtless excited by the contact of the two dissimilar metals, and the frothy compound lasts no longer than the existence of the potassium in the metallic state. In the action which I have just described, bet ween mercury and finely- divided platinum, the permanence of the metals produces a much more lasting effect, and the soft amalgam may be pre- served for a great length of time without altering its appear- ance. At all events, these results cannot but increase the strong doubts which previously existed concerning the hypo- thesis of the metallization of ammonia, and the supposed compound of mercury and ammonium. * Philosophical Transactions) 1822. Part II., p. 262. ( 13 ) ON THE MEANS OF GIVING A FINE EDGE TO RAZORS, LANCETS, AND OTHER CUTTING INSTRUMENTS. BY THOMAS ANDREW KNIGHT, ESQ., F.R.S., President of the Horticultural Society, &c. TN the preparation of steel, and in the art of subsequently forming it into cutting instruments, the British manufac- turers are, I believe, unrivalled ; and they have probably approximated, if they have not attained, perfection : but in the art of giving the finest possible edge to their instruments, when formed, I think that they have generally still some- thing to learn ; for I hear surgeons often complaining, that they rarely find themselves in possession of a perfectly well set instrument ; and I have never yet, in any instance, seen a razor come from a cutler so set that I could use it with any degree of comfort, though I have obtained razors from many of the most eminent manufacturers of the metropolis. The machinery which they employ has long appeared to me to be imperfect and uncertain in its mode of operating, and in many respects inferior to that which I have been some years in the habit of using, and which I shall proceed to describe. This consists of a cylindrical bar of cast steel, three inches long without its handle, and about one-third of an inch in diameter. It is rendered as smooth as it can readily be made with sand, or, more properly, glass-paper, applied longitudi- nally; and it is then made perfectly hard. Before it is used, it must be well cleaned, but not brightly polished, and its sur- face must be smeared over with a mixture of oil and the char- coal of wheat straw, which necessarily contains much siliceous earth in a very finely reduced state. I have sometimes used the charcoal of the leaves of the Elymus arenarius and other marsh grasses ; and some of these may probably afford a more active and (for some purposes) a better material ; but upon this point I do not feel myself prepared to speak with decision. In setting a razor, it is my practice to bring its edge (which must not have been previously rounded by the operation of a strop) into contact with the surface of the bar at a greater or 14 Mr. Knight on the Means of giving less, but always at a very acute angle, by raising'the back of the razor more or less, proportionate to the strength which I wish to give to the edge; and I move the razor in a succession of small circles from heel to point, and back again, without any more pressure than the weight of the blade gives, till my object is attained. If the razor have been properly ground and prepared, a very fine edge will be given in a few seconds; and it may be renewed again, during a very long period, wholly by the same means. I have had the same razor, by way of experiment, in constant use during more than two years and a half; and no visible portion of its metal has, within that pe- riod, been worn away, though the edge has remained as fine as I conceive possible ; and I have never, at any one time, spent a quarter of a minute in setting it. The excessive smoothness of the edge of razors thus set led me to fear that it would be indolent, comparatively with the serrated edge given by the strop ; but this has not in any degree occurred ; and therefore I conceive it to be of a kind admirably adapted for surgical purposes, particularly as any requisite degree of strength may be given with great precision. Before using a razor after it has been set, I simply clean it on the palm of my hand, and warm it by dipping it into warm water ; but I think the instrument recommended operates best when the temperature of the blade has been previously raised by the aid of warm water. A steel bar, of the cylindrical form above described, is, I think, much superior to that of a plane surface for giving a fine edge to a razor or penknife ; but it is ill calculated to give a fine point to a lancet ; and I therefore cause a plane surface to be made, a quarter of an inch wide, on one side of the bar, by cutting away a part of its substance ; and I have found this form to be most extensively useful. The edge of some razors, whether formed of wootz, of mixed metals, or of pure steel, but particularly of mixed metals, has generally appeared to me to be more keen and active when used a few seconds after it had been applied to the bar, than on the following day ; and I have often seen the utmost activity restored to the edge of such instruments, so instantaneously, and by so apparently inadequate means, that I have been a fine Edge to Cutting- Instruments. 16 sometimes led to suspect the operation of the bar to have been something more than that of having worn away a minute por- tion of the metal : but I am not disposed to offer any conjec- tures respecting other effects which I may have conceived it to produce. I have in many instances been able to give a very fine edge to razors in possession of my friends, which I could not set tolerably well by any of the ordinary means; and I have found that those composed of different materials could be set with equal facility, though the sensations they excited, when used, appeared to me to be in many instances dissimilar. The instruments upon which I have chiefly made experiments have come from the manufactories of Mr. Pepys. Mr. Stoddart, and Mr. Kingsbury. The material which appeared to me to receive that which I shall call the most eager edge (and it was very durable) was wootz, from the manufactory of Mr. Pepys; and that which received the smoothest edge^ and which I thought best calculated for surgical purposes, was the mixture of rhodium and steel ; the powers of the pure steel of Mr. Kingsbury appeared to be intermediate : and my experience leads me to believe that, under different circumstances, each of these materials might be used with some exclusive advan- tages. ON THE PECULIAR HABITS OF CLEANLINESS IN SOME ANIMALS, AND PARTICULARLY THE GRUB OF THE GLOW-WORM. BY J. RENNIE, A.M., A.L.S. TN an excursion, for the purposes of natural history, to the woods in the vicinity of Dartford, in Kent, the 14th of last March, I found an insect, which I had not hitherto met with, creeping upon the mossy trunk of an oak, which, besides, was entwined with honeysuckle ; and, near the bottom, a fern plant was rooted amongst the decaying bark. This insect much resembled the female glow-worm in external appearance, but it was considerably longer, and the colours different. Its head, though small, was formed like those of the grubs of pre* 16 Mr. Rennie on the Cleanliness of Animals. daceous beetles, whence I conjectured it might belong to some of their numerous families ; but lest I might be deceived in this, and that after all it might be a vegetable feeder, I put some of the oak bark, moss, fern, and honeysuckle, along with it into a collecting-box. Into the same box I afterwards put several specimens of small snails, with pellucid shells, which I found in the same locality — a circumstance which led me to the discovery of one of those facts that, after eluding direct research, are often the result of accident. It was not till next day that I looked into the box, when I perceived that none of the vegetable substances had been touched, for the snails had glued themselves to the lid, ac- cording to their usual custom when put into a dry place ; and though the little stranger was sufficiently lively, and walked about in all directions, nothing within reach appeared to suit its taste. After watching it for some time, my attention was drawn to some very singular movements which it made with its tail, and which the reader will understand better if he has observed how the common earwig, or the insect popularly called the devil's coach-horse, (Goerius olens, STEPHENS,) bends up its tail over its back, somewhat in the manner of a spaniel when it trips along well pleased before its master. The forked tail of the earwig, however, as well as that of the goerius, is said to be used in assisting to unfold its long and closely-folded wings, an operation which I have never myself witnessed ; but as the strange insect had evidently no wings, this could not be the design of the movements to which I have alluded. I have more than once seen a female moth strip the down from her body to furnish her eggs with a warm covering, for which purpose she bent in the required directions an instrument like a pair of tweezers, situated at the extremity of the tail ; but in the in- stance in question this could not be the case, as there was no down on the body : and yet, upon closer inspection, it seemed to be pulling off something very assiduously from the parts upon which the extremity of the tail was turned back. There appeared to be something so uncommon in these movements, that my curiosity was excited to observe them more minutely ; and as the creature was not at all timid, I could easily observe it through a glass of some power. The Mr. Rennie on the Cleanliness of Animals. 17 caudal instrument I discovered, by this means, to consist of a double row of white cartilaginous rays, disposed in a circle, one row within the other ; and, what was most singular, these were retractile, in a similar manner to the horns of the snail. The rays were united by a soft, moist, gelatinous membrane, but so as to be individually extensile ; one or two being frequently stretched beyond the line of the others. The rays were also capable of being bent as well as extended, and they could therefore be applied to the angles or depressions of an uneven surface. It was not long before I convinced myself that this singular instrument was employed by the insect for cleaning itself ; and it would have been difficult to devise anything more effectual for the purpose, though its action was different from all others of this kind with which I was acquainted, inasmuch as it operated by suction, and not as a comb, a brush, or a wiper, of which I shall mention some examples in the sequel. It was, moreover, furnished in the interior with a sort of pocket, of a funnel shape, formed by the converging rays, into which was collected whatever dust or other impurities were detached from the body, till it could hold no more, when, by a vermi- cular movement of the rays, the accumulated pellet was ex- truded, and placed with great care in some place where it might be out of the way of again soiling the glossy skin of the insect. This skin, if I may call it so, was of a soft, leathery appearance; exhibiting, when magnified, a minute delicate dotting, similar to shagreen — but to the naked eye this was not apparent. a a Magnified views of the cleaning Instrument, open and closed, a, the under side of the body j bt the cleaning instrument. VOL, I. OCT. 1830. 18 Mr. Rennie on the Cleanliness of Animals. The instrument just described, accordingly, when expanded over a portion of this shagreened surface, was subsequently drawn out, with an evident effort, (repeated, if necessary,) in the same way as boys draw their moist leather suckers, when they amuse themselves in dragging stones after them. Every particle of dust or other extraneous matter is thus detached from the skin, and, by a peculiar movement of the retractile rays, is lodged in the funnel-shaped pocket. Larv of the glow-worm on a tendrilled branch, using its cleaning instrument. This singular instrument is also used for the very different purpose of assisting the animal to walk, and particularly to maintain a position against gravity, which its feet are ill calcu- lated to effect ; though its habits, as we shall presently see, render it in some measure indispensable. Larva walking against gravity by means of the funnel at the anus. The interest which I began to take in the insect induced me to endeavour to ascertain its species $ and on turning over the Mr. Rennio on the Cleanliness of Animals. 19 voluminous work of Baron de Geer, I found it was accurately described and figured by him as the grub (larva) of the female glow-worm, (Lampyris noctiluca ;) but though he had bred several of these, he does not seem to have observed their sin- gular mode of cleaning themselves, which I have just described. He was also unsuccessful in discovering their peculiar food. * I know not,' says he, ' what it eats ; but the form of its teeth would make me suppose it to be carnivorous. It lived with me on moist earth, where I 'strewed grass and the leaves of various plants; having remarked that it became feeble and languishing when I failed to supply it with moisture*.1 Two of the most celebrated French naturalists of the present day make a similar statement respecting its food. ' It is be- lieved,' says Dumeril, ' that the glow-worms are carnivorous in the perfect state, but that their grubs (larva) feed on vege- tables— what, is unknown f.' ' This grub,' says Latreille, * though furnished with strong jaws, (which would indicate that it is carnivorous,) feeds upon grass, and leaves of various plantsj ;' but I doubt whether this is not a hasty and un- warrantable inference from De Geei*. The actual food of the grub in question shews, in a very striking point of view, the design of Providence in furnishing it with the instrument which I have described. I was not a little surprised one day to observe the creature moving about with one of the little snail-shells on its head, and could not Larva feeding on a small snail. * De Geer, Mem. Insectes, vol. iv., p. 48. f Diet, des Sciences Naturelles, vol. xxv., p. 21 Nouvcau Diet, d'Histoire. Naturclle, vol. xvii., 284. C 2 20 Mr. Rennie on the Cleanliness of Animals. conjecture what had made it take a fancy to so singular a helmet ; but I soon perceived that it was in fact making prey of the poor snail — having, for that purpose, thrust its narrow extensile head half to the bottom of the shell, which it did not quit till it had devoured the inhabitant. It was thus proved to me that it was not a vegetable feeder, but carnivorous ; and I subsequently found, upon trial, that it would touch no animal except snails. Its head, from being extensile, is well adapted for pursuing its prey to the inmost recesses of their shells ; and its mandibles, which are curved in form of a pair of calliper compasses, appear, as in the in- stance of the grub of the ant-lion (Myrmeleon formicarius}, to be employed rather for sucking than for eating, though I was unsuccessful in satisfactorily ascertaining this point. Head of the glow-worm grub, a, the head ; b, the neck ; c, the antennae ; d, the jaws. It is more to the present subject to mention, that the grub cannot well devour one of its victims without being soiled with slime ; and accordingly, after every repast, I observed that it went carefully over its head, neck, and sides, with its cleaning instrument, to free them from slime. Though not directly connected with my immediate subject, it maybe interesting to many 'readers to mention that the above grub, as well as those observed by Baron de Geer, distinctly proved the fallacy of the common doctrine respecting the light of the glow-worm, which goes to maintain that it is a lamp, lit up by the female, to direct the darkling flight of the male. ' Ce sont,' exclaims Dumeril, ' les flambeaux de 1'amour — des phares — des telegraphes nocturnes — qui brillent et signalent au loin le besoin de la reproduction dans le silence et Tobscurite des nuits *.' Mr. Leonard Knapp, refining upon this notion, conjectures that the peculiar conformation of the head of the * bictionnaire des Sciences Naturelles, xxv. 216. Mr. Rennie on the Cleanliness of Animals. 21 male glow-worm is intended as a converging reflector of the light of the female, ' always beneath him on the earth.' * As we commonly,' he adds, ' and with advantage, place our hand over the brow, to obstruct the rays of light falling from above, which enables us to see clearer an object on the ground, so must the projecting hood of this creature converge the visual rays to a point beneath */ Unfortunately for this theory, the grubs — which, being in a state of infancy, are therefore incapable of propagating — exhibit a no less brilliant light than the perfect insect. De Geer says the Jight of the grub was paler, but in the one which I had it was not so. He also remarked the same light in the nymph state, which he describes as * very lively and brilliant ;' and, in this stage of existence, it is still less capable of propagating than in that of larva. * Of what use then,' he asks, ' is the light displayed by the glow-worm ? It must serve some pur- pose yet unknown. The authors who have spoken of the male glow-worms say positively that they shine in the dark as well as the females {.' These plain facts appear completely to ex- tinguish the poetical theory. But to return to our immediate subject. A very remarkable instrument, which recent observations seem to prove to be intended for a similar purpose to that of the caudal apparatus of the glow-worm, just described, occurs in the fern-owl, or night-jar (Caprimulgus Europaeus), popu- larly called the goat- sucker, from an erroneous notion that it sucks goats — a thing, which the structure of its bill renders impossible as that of cats sucking the breath of infants, as is also popularly believed. The bird alluded to has the middle claw cut into serratures, like a saw or a short-toothed comb ; the use of which structure seems to have been misunderstood by White of Selborne. Foot of the European night-jar, shewing the pectinated clav Journal of a Naturalist, p. 292, first edition. f De Geer^ Mem. iv. 44. 22 Mr. Rennie on the Cleanliness of Animals. < If it takes/ says he, ' any part of its prey with its foot, as I have the greatest reason to believe it does chafers, (Zantheumia soktitialis, LEACH, MS.,) I no longer wonder at the use of its middle toe, which is curiously furnished with a serrated claw*.' Mr. Dillon has recently controverted this opinion ; his observa- tions leading him to suppose that the serratures are employed by the bird to comb its whiskers (vibrissae)-\ . Mr. Swainson, again, a high authority on such a subject, thinks that the fact of an American group of the same birds (Caprimulyida), which have no whiskers to comb, and an Australian group, which have whiskers, but no serratures on the claws, are dis- cordant with Mr. Dillon's opinion J. It frequently happens, however, that the most ingenious and apparently incontrover- tible reasoning in natural history, is overturned or confirmed by facts accidentally observed. I was, I confess, disposed to think Mr. Dillon's opinion more plausible than true, and to agree with White, and the learned arguments of Mr. Swainson, till I met with some observations of the distinguished American ornithologist, Wilson, upon some of the transatlantic species. In his description of the whip-poor-will ( Caprimulgus vocife- rus), he says, ( the inner edge of the middle claw is pectinated, and, from the circumstance of its being frequently found with small portions of down adhering to the teeth, is probably em- ployed as a comb, to rid the plumage of its head of vermin, this being the principal and almost the only part so infested in all birds §.' Of another species, called chuck- will's- widow (C. Caroli- nensis], he says, ' their mouths are capable of prodigious expansion, to seize with more certainty, and furnished with long hairs or bristles, serving as palisades to secure what comes between them. Reposing much during the heats of the day, they are much infested with vermin, particularly about the head, and are provided with a comb on the inner edge of the middle claw, with which they are often employed in ridding themselves of these pests, at least when in a state of captivity ||.' Considering the utility of such an instrument, we may wonder, * Nat. Hist, of Selborne, i. 160. Ed. Lond. 1825. f London's Mag. of Nat. Hist. ii. 31. J Ibid. iii. 188. § Wilson's American Ornithology, v. 77. || Ibid. vi. 97. Mr. flennie on the Cleanliness of Animals. 23 perhaps, that, besides the herons (Ardetf), no other birds are similarly provided for attacking those troublesome insects (Ho- maloptera, MACLEAY, Nirmida, LEACH, &c.), which often seriously injure the vigour and health of the animal infested, and sometimes even occasion death. On going to visit the ruins of Brougham Castle, in Cumberland, I was struck by the unusual tameness of a swallow (Hirundo rustica), which I found sitting on the parapet wall of the bridge which crosses the Emont, on the road from Penrith. Swallows are, indeed, far from being generally shy, trusting, perhaps, to their rapi- dity of flight should danger threaten ; but this poor swallow allowed itself to be approached, without offering to escape. It seemed, in fact, instinctively courting human aid, at least I was inclined so to interpret its pitiful looks. On taking hold of it, I found the feathers swarming with an insect (Craterina Hi- rundinisy OLFERS) somewhat larger in size than the common house-bug (Cimex lectularius). I took the poor bird imme- diately to the river ; and, on being freed from its tormentors, it flew off joyfully to join its companions. Had it been fur- nished with a comb, like the night-jars, it would not probably have needed my assistance. It may not fall in the way of many of the readers of this paper to make personal observations on the foot-comb of the night-jar; but similar instruments, of still more ingenious con- struction, may be inspected, by whoever will take the trouble, in two of our most common animals — the cat and the house-fly1 (Musca domestica), both of which may very frequently be seen cleaning themselves with the utmost care. The chief instru- ment employed by the cat is her tongue ; but when she wishes to trim the parts of her fur which she cannot reach with this, she moistens, with saliva, the soft spongy cushions of her feet, and therewith brushes her head, ears, and face, occasionally extending one or more of her claws to comb straight any matted hair that the foot-cushion cannot bring smooth, in the same way as she uses her long tusks in the parts within their reach. The chief and most efficient cleaning instrument of the cat, however, is her tongue, which is constructed somewhat after the manner of a currycomb, or rather of a wool-card, being beset with numerous horny points, bent downwards and back- 24 Mr. Rennie on the Cleanliness of Animals. wards, and which serve several important purposes, such as lapping milk, and filing minute portions of meat from bones. Magnified view of a portion of the upper surface of the Cat's Tongue. But what falls chiefly to be noticed here, is its important use in keeping the fur smooth and clean ; and cats are by no means sparing in their labour to effect this. The female cat is still more particular with her kittens than herself, and always em- ploys a considerable portion of her time in licking their fur smooth. The little things themselves, also, begin, when only a few days old, to perform the office for themselves ; and I have observed the half-fledged nestlings of the black cap (Sylvia atricapilla), and a few other birds, preening their feathers as dexterously almost as their dam herself could have done. It requires the employment of a microscope of considerable power, to observe the very beautiful structure of the foot of the two-winged flies (Muscidce), which still more closely re- sembles a currycomb, than the tongue of the cat does. This structure was first minutely investigated by Sir Everard Home 'and Mr. Bauer, in order to explain how these insects can walk upon a perpendicular glass, and can even support themselves against gravity. Of the structure of the foot of flies, con- sidered as an instrument for cleaning, I have not hitherto met with any description in books of natural history, though most people may have remarked flies to be ever and anon brushing their feet upon one another, to rub off the dust, and equally assiduous in cleaning their eyes, head, and corslet with their fore- legs, while they brush their wings with their hind legs. In the common blow-fly (Musca carnaria), there are two rounded combs, the inner surface of which is covered with down, to serve the double purpose of a fine brush, and to assist in forming a vacuum when the creature walks on a glass, or on the ceiling of a room. In some species of another family (^mlidce), there are Mr. Rennie on the Cleanliness of Animals, 25 A, side view of the last joint of the leg of the blue-bottle fly (musca vomitoria.) B, do. of the fever fly (bibio febrilis.} Both figures magnified 100 times. three such combs on each foot. It may be remarked, that the insects in question are pretty thickly covered with hair, and the serratures of the combs are employed to free these from entangle- ment and from dust. Even the hairs on the legs themselves are used in a similar way ; for it may be remarked, that flies not only brush with the extremities of their feet, where the curious currycombs are situated, but frequently employ a great portion of their legs in the same way, particularly for brushing one another. Birds are peculiarly distinguished for their cleanliness, which appears to be instinctive ; that is, it becomes apparent very soon after they are hatched, at least in those nestlings which are at first blind ; the others (Gallina, &c.) do not so much requireit, from their running off immediately out of the nest after their dam. The parents of blind nestlings are particu- larly careful in watching, after feeding, till they moot, car- rying it off in their beaks, an office which they even perform for the female while she is hatching. I have particularly re- marked this in the common starling (Sturnus vulgaris), a thing the more necessary, from the bird nestling in the holes 26 Mr. Rennie on the Cleanliness of Animals. of trees ; and Colonel Montague observed it in the gold-crested wren (Regulus cristatus, RAY,) in the instance of a nest of young which were fed by the parents after being carried into a room*. ' In birds,' says White, ' there seems to be a parti- cular provision, that the moot of the nestlings is enveloped in a tough kind of jelly, and therefore is the easier conveyed off without soiling or daubing. Yet, as Nature is cleanly in all her ways, the young perform this office for themselves in a little time, by thrusting their tails out at the aperture of their nests f.' Another delightful writer says, c birds are unceas- ingly attentive to neatness and lustration of their plumage. Some birds roll themselves in dust, and occasionally particular beasts cover themselves with mire ; but this is not from any liking or inclination for such things, but to free themselves from annoyances, or to prevent the bites of insects £.' I may be permitted to illustrate one of these remarks of Mr. Knapp, by mentioning the fact, that in some parts of Africa the elephant and the rhinoceros, in order to protect themselves from flies, roll themselves in mud, for the purpose of forming an impenetrable crust upon their skin when it becomes dry. Their most formidable insect pest, according to Bruce, is a fly called Tsalfaya, belonging, it would appear from the descrip- tion, to Clairville's Haustellata. It is said not to be larger than a common bee, but is more terrible to those two animals than the lion himself. It has no sting, but insinuates its sucker (haustellum) through the thickest skin, in the same manner as our cleg (Hamatopota pluvialis, MEIGEN) does. The effects of this sucking are such, that the part not only blisters, but frequently mortifies, and in the end destroys the animal ; but the coating of dried mud over the skin affords them effectual protection, and therefore cannot be justly quoted as an instance of their dirty habits. It is highly probable, as it appears to me, that the proverbially unclean habits of swine may be re- ferred to a similar origin, particularly as no animal is more careful to have its bed clean and dry. There is another family of animals no less repulsive to the feelings of many people, though not proverbially dirty as the * Ornith. Diet. Introd. f Nat. Hist. ofSetborne, i.269. I KNAPP, Journ, of a Naturalist ,311. Mr. Rennie on the Cleanliness of Animals. 27 swine, which I have discovered to be peculiarly cleanly ; I refer to the several species of spiders. During the course of a series of observations and experiments on the process by which they can shoot lines of their gossamer silk across a brook, or other intervening obstacle, it was indispensable that I should pry with minute attention to their every movement ; and I was soon struck with one which interested me not a little, in the instance of one of the long bodied species, (Tetracjnatha extensa, LATREJLLE.) It appeared to be mumbling, if I may use the term, its legs between its mandibles, drawing each leisurely along, as a dog may be seen to gnaw a bone when not very much in earnest, but more by way of pastime than of making a dinner. I could not at first account for this ; the ancient naturalists, who drew largely on their imagination when facts failed them, would at once, I have no doubt, have leapt to the conclusion, that the spider, in default of prey, actually devoured its own legs, as it has been asserted to do its web*. A little attention convinced me, that the movements alluded to were precisely1 of the same kind as the preening of birds. Spiders have their legs more or less covered' with sparse hair, which, being rather long and bristly * is apt to catch up bits of their own web and other extraneous matters, and these, from the delicacy of their semi-transparent skin, must produce un- comfortable irritation. To free themselves from this is one of their daily occupations ; and when a spider appears to the less minute observer to be quite at rest, it will often be seen, on close inspection, to be assiduously and slowly combing its legs in the manner I have above mentioned. The term combing is very appropriate in the instance of the common garden-spider (Epeira diadema), which is furnished with a set of teeth some- what in form of a comb; but it has another instrument in addition to this, peculiarly useful in the process, consisting of a smooth and somewhat curved horny needle, which bends over the teeth of the comb, and holds the limb which it is dressing more firmly down, as if, after entering it in the hair, we were to apply a finger over the edge of one of our artificial combs. In some other spiders (Dysdera erythrina, &c.), there is, in the situation of the comb just described, a closely set brush of * BLOOMFIELD'S Remcunsy vol. ii. 28 Mr. Rennie on the Cleanliness of Animals. thick hairs, which is employed in the same way. Any person who will take the trouble may readily verify these observations by confining a spider in a wine-glass, placed in a saucer filled with water, from which it cannot escape, so long as there is no current of air to carry off a silken line for a bridge. Those who have paid attention to ants, may have remarked that a pair of them may be often seen touching one another with their antenna?, and even passing their tongues over part of each other's bodies, in the same way as they are seen to do with their eggs, larvae, and pupae, erroneously imagined by the ancients to be hoarded grain. The necessity which they are under of moving these to various parts of the colony, in consequence of variations in the weather, must often expose them (polished though they be) to soiling; but the careful nurses instantly remove every thing of this sort with their mandibles, or tongue • — movements which have been misinterpreted, as licking the pupae into shape ; as the bear is no less erroneously asserted to do by her cubs. In all such cases, cleanliness seems to be the chief, if not the sole, motive ; as those mutual caresses of the working ants are, I think, for the same purpose. These, indeed, remind me strongly of the common practice of horses and cows of cleaning each other's necks and heads, which the individual cannot itself reach with its tongue ; and, in the same way, caged birds will sometimes do the friendly office to a fel- low-prisoner, of pecking off anything extraneous adhering to the head or the bill, where preening is impossible, and the foot is seldom well adapted to the purpose. Such are a few of the illustrations which have suggested themselves to me upon this subject : should they be found interesting, I may probably add a few more at a future op- portunity. Lee, Kent, 1st July, 1830. DESCRIPTION AND APPLICATION OF A TORSION GALVANOMETER. BY WILLIAM RITCHIE, A.M., F.R.S. Assoc. Mem. S. A. for Scotland, Rector of the Royal Academy of Tain. TN a paper which appeared in the first part of the Philoso- '• phical Transactions for 1830, 1 investigated the elasticity of threads of glass, and applied that property to the construc- tion of a delicate and accurate galvanometer. The instrument then described, though sufficient for most purposes, requires some modification to adapt it to researches of extreme delicacy. The description of the instrument, in this more perfect state, with a few of its numerous applications, will form the subject of this communication. For experimental researches in electro-magnetism, it is ex- tremely useful to have constantly at hand a quantity of copper wire, of different degrees of fineness, coated with sealing-wax. The most convenient mode of giving the wire this coating, is the following : — Stretch the wire between two supports, heat it gradually, from one end to the other, with an iron bar, or spirit-lamp, and continue rubbing the heated part with a stick of sealing-wax ; the wire will receive a fine coating, sufficient to prevent metallic contact when portions of it are pressed together in the construction of any piece of electro-magnetic apparatus. Take the wire thus coated, heat it slightly to prevent the wax cracking, and form it into a rectangular shape, consisting of six, eight, or ten repetitions of the wire, according to the delicacy of the instrument required. The upper side of the rectangle must then have the wires separated into two equal portions, bent round a small cylinder, and then continued straight, so as to leave a circular opening in the middle, about one-third of an inch in diameter. The use of the circular open- ing, in the upper side, is to allow a slender axis, carrying the magnetic needles, to pass through it, in order to increase the power of the instrument, and render the compound needle 30 Mr. Ritchie on a Torsion Galvanometer. astatic. Portions of a brass tube, about an inch long, are to be soldered to the ends of the wires forming the rectangle, for the purpose of holding a small quantity of mercury, to render the metallic contact complete. The annexed cuts exhibit a vertical section of the rectangle, and a horizontal one of its upper side. II The wires, forming the rectangle, are pressed close together, and secured by a waxed sewing-thread, rolled tightly round them. The rectangle is then fixed in a rectangular box, having the upper side formed of two sliding panes of window glass, for the purpose of shutting up the needle from the agitation of the air. Each pane has a small semicircle cut out of the middle of the edge, by means of a round file, so as to leave a circular opening directly above that in the rectangle. Various contri- vances for suspending the magnetic needle might be adopted. The following is perhaps the most convenient : — Into a strong wooden sole, or base, fix two upright supports about three feet long. A small stage at the top, having a divided circle on its upper side, and which may be elevated or depressed at pleasure, completes the frame of the instrument. The stage has two holes of the same size as the supports, and at the same distance, with two small screws passing through its sides, opposite the centres of the openings, for the purpose of fixing the stage securely at the proper height. A small cylindrical wooden key or peg, having a small bore in the axis for the purpose of receiving the end of the glass thread, passes through the centre of the divided circle, and is made to turn easily, without much friction. After numerous trials, the following appears to me the best mode of preparing the threads of glass, so as to have their extremities somewhat thick and tapering, for the purpose of securing them in the torsion key, and in the axis which carries Mr. Ritchie on a Torsion Galvanometer. 31 the magnetic needles. Take a solid rod of glass, or a piece of a clean thermometer tube, having a very fine bore, and draw out one of its ends, as in the annexed cut. Direct the very point of the flame on the thick portion at A, and pull it out, between the two hands, to the proper length. As it is hardly possible to get a thread of glass of the proper length and fineness, at the first trial, it will be found necessary to draw several, and select the one best adapted to the purpose. Two slender darning needles, of the best steel, are then to be selected, the eyes to be broken off, and the ends filed to a point similar to the other ends, and then strongly magnetised in the usual way. The needles are then to be fixed transversely in a piece of straw, or other light substance, about an inch long, and at the distance of about half an inch from each other, with their corresponding poles in opposite directions — the one needle in- tended to be above the upper side of the rectangle and the other below it. One end of the glass thread is then to be securely fixed in the end of the straw, or light axis, by means of strong cement or sealing-wax, whilst the other extremity is fixed, in like man- ner, in the centre of the torsion key. A single fibre of silk, having a small weight attached to it, is fixed to the lower end of the axis, and made to pass through a small hole near the lower side of the rectangle, for the purpose of keeping the axis carrying the needles, in the centre of the circular opening in the coil. The upper needle has two pieces of fine straw, several inches long, fixed on its ends, so that the slightest deflection may be readily observed. The extremity of one of the straws is made to oscillate between two upright pieces of glass, to prevent the needle moving over an extensive arc, and thus lengthen the time necessary to complete an observation. The whole will be obvious from the simple inspection of the an- nexed vertical section of the instrument, in which A B is the rectangular coil of wire, NS, S' N', the magnetic needles; C^ the stage with the divided circle and torsion key, and G the glass thread. If, instead of the glass thread, the needle be 32 Mr. Ritchie on a Torsion Galvanometer. suspended by a single fibre of silk, the instrument becomes a galvanoscope of extreme delicacy. The following experiment affords a striking illustration of the extreme sensibility of the instrument with this modification. EXPERIMENT I. File off a few grains from a piece of zinc and] copper by means of a coarse file ; place two of these near each other in the bottom of a clean watch glass ; bring the clean ends of two fine copper wires, connected with the cups of the galvanometer, in contact with them, and then drop over them a small quantity of dilute acid, and the compound needle will be deflected several degrees. Mr. Ritchie on a Torsion Galvanometer. 33 The instrument by which I ascertained the existence of a Voltaic current from this elementary battery, consisted of a greater number of coils in the rectangle, and the needles were light and strongly magnetised. Having thus minutely described the torsion galvanometer, I will now shew some of its applications ; but before doing this it may be thought necessary to establish its accuracy, not by reasoning (which is already done in the Philos. Trans.), but by direct experiment. The following experiments will shew in a striking manner the perfection of this instrument above those formerly employed. EXPERIMENT II. Take two equal rectangular slips of copper and zinc, an inch broad and eight or ten inches long, and divide them into square inches by narrow bands of wax or cement. Solder copper wires to their extremities, and fix them in a small frame, so that they may always be placed at the same distance from each other. Immerse them in a vessel of water, containing a small quantity of sulphuric acid, to the first horizontal divi- sion ; turn round the torsion key till the untwisting force of the glass thread balances the deflecting power of the electric current, and note the number of degrees of torsion. Immerse them to the second division, turn round the torsion key as before, and the degrees of torsion necessary to balance the deflecting force of the current, from two square inches, will be found double of those for one square inch. Repeat the experi- ment with three, four, &c., square inches, and the degrees of torsion will be found to be proportional to the surface of the plates immersed. Having thus shewn experimentally the accuracy of the instrument, I shall now apply it to determine the power gained by Dr. Wollaston's contrivance of a Galvanic battery above those formerly in use. EXPERIMENT III. Having provided a clean slip of copper, two inches broad and about four inches long, I formed it into a rectangle, open VOL. I. OCT. 1830. » 34 Mr. Ritchie on a Torsion Galvanometer. at the top, and then covered the inner surface of the bottom with cement. A plate of zinc, of the same size with the rectangle of copper, was placed exactly in the middle, hav* ing a face of clean copper opposite each of the sides of zinc. Copper wires being soldered to the rectangle of copper and to the plate of zinc, and their ends dipped into the small metallic cups of the galvanometer, the elementary battery was then immersed in very dilute acid, and the torsion key turned till the deflecting force of the battery was vanquished, the number of degrees being about a thousand. Having removed the battery, I covered one side of the plate of zinc and the opposite surface of copper with cement, and repeated the expe- riment as before ; when, as might naturally be expected, the number of degrees of torsion were found to be very nearly five hundred. We may, therefore, safely conclude that the double plate of copper doubles the quantity of electricity without, of course, altering its tension. Immediately after (Ersted's beautiful discovery of the mu- tual action of magnets and Voltaic conductors, it was known that an immense increase of electro-magnetic power is gained by diminishing the distance between the copper and zinc plates ; but, for want of a proper galvanometer, the law does not seem to have been determined with that rigorous accuracy which places its truth beyond the possibility of doubt. To accomplish this was the object of the following experiment. EXPERIMENT IV. In order to avoid every source of inaccuracy, I procured a rectangular wooden box, about a foot long, two inches broad, and two and a half inches deep, into which plates of zinc and copper two inches square might be fixed at any distance from each other. Having filled the box with dilute acid, I placed the copper plate at one extremity and the zinc plate at the distance of nine inches, and observed the degree of torsion, as in the preceding experiments. I then untwisted the thread, placed the zinc at the distance of one inch from the copper, and observed the degrees of torsion, which were now nearly three times as great as before, This was next repeated with the Mr. Ritchie on a Torsion Galvanometer. 35 plates at the distance of nine and four inches, and gave the deflecting forces in the ratio of 2 to 3, which are the square roots of 9 and 4. After trying the effects of the plates at different distances, the following law was established, which had formerly been obtained by a different process : viz. — that the quantity of Voltaic electricity circulating along the metallic conductor connecting two plates of dissimilar metals, is inversely as the square roots of the distances between the two plates. This law was originally deduced by Professor Gumming, by observing the deflection of a compass needle, and then taking the deflecting forces as the tangents of the angles of deviation from the original direction of the needle and straight conductor. When I undertook this investigation, it had escaped my me- mory that any law had been discovered which connected the deflecting force with the distance of the plates. This circum- stance, as well as the different process by which it was deduced, affords the most complete proof of its truth. This law is certainly very different from what we might at first have expected. We might, without experiment, have argued thus: If one inch of fluid between the plates offer a certain resistance to the electric current, two inches will pre- sent twice the resistance, three inches three times the resist- ance, 8fc. &c. With regard to the cause of this curious law, we can at present scarcely offer a conjecture. Does the electric fluid, after passing through a certain length of an imperfect conductor, acquire some power which enables it to pass more easily through an equal portion ? There are phenomena in nature in which imponderable agents do acquire such proper-* ties, Light may be so far modified as to pass entirely through glass, which, without such a modification, would have been partly reflected. De Laroche discovered that invisible radiant heat, after passing through a thin plate of glass, passes with less resistance or loss through a second, &c. But, instead of being led away by analogies, which by some may be regarded as fanciful, I shall mention one practical lesson to be deduced from the law in question. In constructing a battery for electro- magnetic purposes, there is not so much power gained as might be supposed by putting the plates very near each other. For example, if the plates are at the distance of a quarter of an D 2 36 Mr. Ritchie on a Torsion Galvanometer. inch, and then at the distance of one-eighth of an inch, the power gained will only be as the square root of .25 to the square root of .125, or nearly as 50 to 35 ; and the hydrogen constantly escaping, and partially occupying the place of the liquid in the narrow cell, considerably diminishes this apparent increase of power. This circumstance ought not to escape the attention of philosophical instrument-makers in the construc- tion of batteries for electro-magnetic purposes. Considerable uncertainty still prevails with regard to the law which connects the conducting powers of metallic wires with their lengths. According to Professors Barlow and Gumming, the law is the same as that established for fluid conductors. According to the experiments of M. Becquerel, the conduct- ing powers of metallic wires are simply as their lengths. The following experiment will set the question at rest. EXPERIMENT V. The galvanometer I have hitherto used requires the following modification for this investigation. Form the rectangle of a single copper wire, and suspend the magnetic needle directly over it, and in the same direction. Take a certain length of the same copper wire, and connect it with a small elementary battery, turn the key, and observe the degree of torsion. Take nine times the length of the same wire, and repeat the experi- ment with the same battery and acid, and the number and degrees of torsion will only be one-third of those obtained in the first experiment. This experiment I repeated with dif- ferent lengths of bell- wire, and always found that the intensity of the current was inversely as the square roots of the lengths — the same as the law for liquid imperfect conductors. M. Becquerel seems to have fallen into the mistake we have now pointed out, by using a galvanometer made of a long wire formed into a coil, and neglecting the resistance the electric current must have experienced in passing through the instru- ment itself. The conducting powers of metallic wires, or their ribands, for common electricity, depends almost entirely on their surface, without any reference to their thickness. The fact would seem to be, that common electricity glides along the surface of the Mr. Ritchie on a Torsion Galvanometer. 37 metal, being prevented from escaping by the pressure of the am- bient air, whereas Voltaic electricity requires a certain thickness of metal for its transmission*. Voltaic electricity, from a single pair of plates, seems to be conducted from molecule to molecule, in some measure resembling the conduction of caloric. Hence, if the diameter of the wire be too fine to allow of this depth of metal, a considerable portion of the electric fluid will be stopped. But, provided the wires be sufficiently thick to allow of this necessary depth of the electric film, then the conducting power ought to be nearly as the circumference of the wire, or as its diameter. If one of the wires be very fine, and the other of a large diameter, this law could not exist. This fact was clearly proved by the following experiment. EXPERIMENT VI. Having taken equal lengths of very fine copper wire and of common bell wire, I used them successively as conductors from the same elementary battery, and ascertained the degrees of torsion as in the former experiments, and found that the large wire conducted better than in the mere ratio of the diameters. For example, the diameter of the one wire was scarcely three times that of the smaller, yet the ratio of their conducting powers was nearly as one to four. I then passed the thick wire through rollers, till it was reduced to a very thin riband, hav- ing its external surface nearly twice that of the original wire, but instead of conducting double the quantity of the original wire, it conducted only three-fourths of that quantity f. From the law established in the fourth Experiment, we need scarcely despair of seeing the Electro-Magnetic Telegraph established for regular communication from one town to another, at a great distance. With a small battery, consisting of two plates an inch square, we can deflect finely-suspended needles * Hence if a metallic rod be raised to a red heat, its power of conducting com- mon electricity is increased, whilst its conducting power for Voltaic electricity is con- siderably diminished. f The fact here established bears a striking analogy to a curious fact discovered by Mr. Barlow. He found that it requires a certain thickness of iron or steel to receive the magnetic influence — Is there any relation between the thickness of the iron or steel necessary to receive the magnetic influence and the thickness of the conductor necessary to convey that kind of electricity which acts most power- fully on the needle ? " 38 Mr. Ritchie on a Torsion Galvanometer. at the distance of several hundred feet, and consequently a battery of moderate power would act on needles at the distance of a milej and a battery of ten times the power would deflect needles with the same force, at the distance of a hundred miles, and one of twenty times the force, at the distance of four hun- dred miles, provided the law we have established for distances of seventy or eighty feet hold equally with all distances what- ever. PRACTICAL AND PHILOSOPHICAL OBSERVATIONS ON NATURAL WATERS. BY WILLIAM WEST, ESQ. § 1. On the Water from Peat Lands, and its application to domestic purposes. T HAD an opportunity, some time since, of closely examining many specimens of water from this part of the country, (Leeds,) which were soft and nearly pure, containing from half a grain to two grains of solid matter in the gallon, one part in 50 or 60,000, but tinged by colouring matter from peat. With most of the re-agents no action took place, or it was so slight as to be difficult of detection ; but when evapo- rated until a gallon was reduced to a few spoonfuls, the com- position of this small portion was easily shewn to be sufficiently complicated : and it varied greatly in different specimens which, passing in their original state under the action of the tests with- out any alteration being produced, might have been supposed exactly similar. The fact is, the water precipitated from the rain and mountain mists had taken up small portions of the soluble substances which came in its way ; but its course had been too short, and its action too much confined to the earth's surface, to acquire much from any of these. These streams were on high moor land; either running in the ravines, or springing from natural or artificial openings in mill-stone grit. One practical difficulty of considerable importance arises when water from brooks in such situations is employed, or Mr. West on Natural Waters. 39 when a large quantity of such water has to be collected for the supply of a town. The upland streams, deriving their supply from high and barren land, barren of all but moss and heather, are more or less deeply coloured by vegetable matter derived from peat. There has occasionally been much controversy respecting this peaty water; and among those who have en- tered keenly into this, both parties have been, I think, some- what in the wrong. While those are mistaken who condemn, in the gross and for every purpose, water tinged in any degree with peat, or who maintain that it cannot be deprived of this colour, they are equally so who treat such an impregnation as not injurious to any of the useful qualities of the water. What may be the exact effect on the human constitution of the small quantity of soluble vegetable matter, of whatever nature, from which the hill streams derive their colour, I do not pretend to say ; but the water is unsightly, not only from the brown tinge, but from the coloured froth formed by the bubbles of air which escape on standing. These, in water in general, break as they reach the surface ; but, from the viscidity produced by the peat, they collect and remain, giving an un- pleasant and repulsive appearance. Now, I hold an opinion, which has been confirmed by some experienced medical men, that the salubrity of water, as a beve- rage, depends less upon its absolute purity than upon its being brisk and palatable. We know how palling to the stomach is water which has been boiled and cooled, or has stood long in open vessels ; yet, so far as the term * pure water' means water free from the presence of other substances than water, such is frequently more pure than when originally drawn. I appre- hend, that though much in diet which is agreeable to the palate is at the same time unwholesome, yet that will not commonly perform its part well which is itself positively disagreeable. Again, in experimenting upon this peaty colour, either as strong as it could be obtained, or in its common and more dilute state, I found it closely to follow the habits of those vegetable infusions which are prepared expressly for the colour they impart. Thus it is found dissolved, not merely suspended, passing any number of times through filtering-paper without 40 Mr. West on Natural Waters. diminution, and not much impairing the transparency or re- fractive power of the water. It is quickly and completely separated by aluminous earth in a state of minute division; the alumine, at first snow-white, becoming brown, and forming a true lake. It is separated by muriate of tin, in flakes com- posed of colouring matter and oxide of tin. Many other of its habitudes agree — all, indeed, which I have compared. Thus it more readily leaves the water> and fixes itself on the material boiled or washed in it, when that is of silk or woollen, animal productions — than when linen or cotton, vegetable fabrics. Printed cotton, however, of bright colours, is at once stained and altered, from the mordant of the print combining with or fixing the additional colour. White linen or calico, on the other hand, once washed in pale yellow water, is not percep- tibly stained ; with deep brown water it is discoloured by the first operation ; and the same result takes place from the re- peated use of that which, in a single trial, produces no sensible effect. Though this substance obstinately resists mere filtering, such as would separate suspended impurities, yet sand, containing, as I apprehend, some alumine, is effectual in separating it: but the kind of sand which will filter at once most speedily and effectually ; the degree of mixture with clay which will produce the greatest chemical effect without lessening mate- rially the permeability of the sand ; the depth of sand required ; the fall or pressure which best unites speed and effect; — all these are points calling for experiment, and which, if not well ascertained before attempting to filter on the great scale, may cause much useless delay and expenditure. Long exposure in reservoirs to light and air, assisted, as I believe, by the action of the clay with which they are lined, destroys the colour. The water with which one large town is supplied enters the reservoirs more deeply stained than any of the streams which formed the subject of my experiments ; and left them, at the time it was brought to me, less coloured than the water of the river Aire. But I am told that, in winter time, when a flood happens, the water from the surface, leaving each reservoir soon after it enters, is delivered from the pipes to the houses Mr. West on Natural Waters. 41 very much discoloured. Where such water, then, must be used, (and from its softness it has many advantages,) a well- arranged and well-managed filter is highly desirable. It may serve to shew how cautious we should be in attri- buting mistakes on scientific points to any writer, from minute criticism of the terms used, to notice that, in an official report from one of the most eminent chemists of the present day, it is stated that the yellow or light-brown peaty water is not, in his opinion, objectionable for * any domestic purpose.' He undoubtedly used the term in a limited sense, confining it to the preparation of food, and to its power as a simple detergent, without taking notice of the probability of its leaving a colour of its own. Again, the Commissioners of 1825, on the Supply of Water to the Metropolis, in their able report, say, « It must, however, be recollected, that insects and suspended impurities only are removed by filtration ; and that, whatever substances may be employed in the construction of filtering-beds, the purity of the water, as dependent upon matter held in a state of solution, cannot be improved by any practicable modification of the process/ &c. &c. Now this, as I have proved by expe- riment, is not applicable to some dissolved animal and vegetable matters : it can only be strictly true as applied to the salts con- tained in water ; and though undoubtedly correct in the general as to these, yet exceptions are still possible. Besides the superiority of filtering over mere subsidence, for the mechanical separation of impurities, I think enough atten- tion has not been paid to the power of alumine to separate both animal and vegetable matter, however perfectly dissolved. I evaporated deep-coloured peaty water, previously filtered and very bright, and obtained at the rate of 1.6 grains from one pint. On calcination, these 1.6 grains were reduced to 0.6. About 0.8 grains of the quantity thus dissipated was vegetable matter ; 0.2 or upwards was carbonic acid, from carbonate of lime. I then separated the colouring matter by well-washed alumine ; the water was left perfectly limpid : on evaporation it left one grain, which, on calcination, became 0.6, as before : allowing for the carbonate of lime decomposed by the heat, not less than four-fifths of the vegetable matter had separated in combination with alumine. 42 Mr. West on Natural Waters. I exposed a weak solution of gelatine to similar treatment, with correspondent results : the greater part was separated in the same manner ; the water evaporated left little but the salts contained in the jelly. I ascertained that common clay pro- duced, by allowing longer time, the same changes in appear- ance, and that the weight of the dissolved matter was less than before ; but I could not easily free the clay so entirely from salts as to bring the proportion separated to the same degree of certainty by weighing. § 2. On the deposition of Sulphate of Lime from Hard Waters, and on the Solvent Power of Hard Waters. Sulphate of lime, being held in waters by its own solubility, cannot be wholly separated by mere boiling : on applying heat to its solution, one of two effects takes place : if the evaporation is slow, the solution is left more concentrated and stronger ; if it be boiled briskly, the solution may remain of the same strength though not saturated, while a portion of the sulphate separates in a solid form. The manner in which this proceeds is curious ; the property is common in a greater or less degree to all sub- stances difficultly soluble, though lime itself is the most strik- ing instance. When a bubble of steam arises, the salt which was dissolved in that portion now vaporized, separates in the solid state ; and as such bodies require not only a large portion of water, but a long time to effect solution, before this is again dissolved, many other particles are separated, and thus the quantity deposited goes on increasing, the strength of the so- lution itself remaining all the time nearly the same, though any difference which may take place is of course in the way of increase. Thus in the production of ' fur,1 in the vessels in which it is boiled, the sulphate of lime acts about as speedily as the car- bonate, and probably more injuriously. In many operations, therefore, it becomes a very serious evil. I was assured at Manchester that it was necessary frequently to empty the engine boilers, and chip out the crust formed, in some cases as often as once in six weeks ; the labour of effecting this, and the hin- Mr, West on Natural Waters. 43 derance to work, and loss of fuel consequent on letting out the fire, are not the only disadvantages attendant upon the cir- cumstance. The boilers must be more quickly destroyed, from the great heat of the outside being very slowly conducted through the earthy crust. In fact, they told me that for a short time before the usual periods for cleaning, it was difficult to get the steam up, whatever firing was used. Nor is the employment of the Sabbath for this purpose to be left out of the question. The adhesion of the earthy matter to the iron is lessened, and the interval between the cleanings consequently protracted, by the use of potatoes, the pulp of which envelop- ing the crystals, lessens their tendency to cohere, and preserves them for a time suspended in the water of the boiler. I have taken much pains with a set of experiments to settle this point, among others, viz., * On the comparative solvent powers of waters holding in solution various salts in different proportions.' I have come to the conclusion, that the earthy salts exert a great influence in preventing the solvent action of water on vegetable substances ; the proportion dissolved by pure or soft water being considerably greater than that by hard water. Portions of tea of the same weight, viz., thirty-six grains after drying, with equal quantities of boiling water of different kinds, standing in similar vessels for the same time, yielded, the hard water, after deducting the weight of the earthy matter, about four grains of extract ; that is, the infu- sion left, besides the earths, four grains, on evaporation to dryness; the leaves again dried weighed thirty-two grains: the extract from the soft, or distilled water was pretty exactly eight grains; the leaves, after drying, twenty-eight grains. Thus, the soft water had extracted from the tea just twice as much as the hard. I made numerous experiments of the same description, but found it difficult, from circumstances con* nected with the absorbent nature of the leaves, to obtain exactly the same quantities of extract and of spent leaves, in repetitions of the same experiment, and cannot, therefore, de- pend on this mode of comparing waters differing little from each other ; and the effect of pure water is certainly very near to that of any natural water containing carbonate of soda. I think, however, that the soda does a little increase the quantity 44 Mr. West on Natural Waters. taken up, and that it is probable the celebrity of these waters for such purposes depends on three circumstances, — the real increase of solvent power ; the darker colour, giving the ap- pearance of greater strength ; and the sensibility of the palate being increased by the soda. § 3. On the Gaseous Contents of Waters. The gases usually found in such waters as are commonly em- ployed for other than medicinal purposes are, carbonic acid gas, azote or nitrogen and oxygen. In the waters containing soda, there are commonly small por- tions of sulphuretted hydrogen and of carburetted hydrogen, but these soon escape on exposure to the atmosphere, leaving the water free from its original unpleasant smell. Oxygen gas is less frequent and less abundant than might be supposed. In many cases I have proved its absence, by introducing into the water substances which readily absorb oxygen, by exposing to such substances the gas separated by boiling, and by exploding a mixture of the gas with a known quantity of oxygen, and more than its equivalent of hydrogen. This absence of oxygen is easily accounted for, where substances exist which would at once combine with it, as oxide of iron, or sulphuretted alkalies ; but I have had the same results in cases where it might have existed without interfering with the constituents of the water. From its absence under these circumstances, as well as upon other grounds, we may infer that the gases disengaged from spring water are not absorbed from the atmosphere, but are formed and taken up by the water while in the earth. Stand- ing water and streams, however, undoubtedly absorb air. Dr Ure states, that he obtained from such waters about l-35th of their bulk of gases, of which from l-20th to l-10th was car- bonic acid, and the remainder common air. He does not, how- ever, say whether he tried any experiments to ascertain this last point, or only assumed it to be so. I have invariably found less oxygen, in proportion to the nitrogen, than in air, and from . the principles which determine the absorption of gases by water, it should be so. I have also always obtained Mr. West on Natural Waters. 45 a greater portion of carbonic acid, as well as a greater volume of the mixed gases. From hard, brisk pump water I obtained, by boiling, quanti- ties which, in round numbers, and for the specific gravity, varied but little, in repeated trials, from sixteen cubic inches of car- bonic acid, and the same quantity of a mixture of azote with a small quantity of oxygen. The water of the Aire, taken from the cut which supplies the waterworks, gave two inches and three-quarters of carbonic acid, and eleven inches and three-quarters of azote and oxygen, the total quantity of gases being less than half that from pump water. From that of a large fish-pond I obtained more gas than from the river, but less carbonic acid, viz., two cubic inches and a quarter of carbonic acid, fourteen inches azote, and two oxygen. It is only within these very few years that carburetted hy- drogen has been recognised in water. Its presence was first noticed, I believe, by Dr. Scudamore and Mr. Garden, inHar- rogate sulphur-water. It is found accompanying sulphuretted hydrogen in every water which I have tried in which that gas occurs, and is disengaged from many springs in much greater quantity than the water can absorb, so as to form large bubbles. This phenomenon has been observed in many parts of the world, and the inflammability of the gas disengaged in such situations had been often noticed, but its exact nature has been in most cases rather inferred than proved. This circumstance of an inflammable gas, great part of which is carburetted hydrogen, issuing spontaneously from water, may be seen in several places in our neighbourhood. At Har- rogate large bubbles occasionally rise through the water. At Stanley there is a continual flow of small bubbles ; the dif- ference depends upon the figure of the well or boring, and that of the passages through which it is supplied. At Slaith- waite the disengagement of gas is still more abundant, so that there is a succession of large bubbles, and the gas may easily be collected in considerable quantities, or set fire to at the surface of the water. The nature and amount of gaseous impregnation, though often of moment in medicinal waters, is almost immaterial for 46 Mr. West on Natural Waters. domestic purposes, with the single exception of water used unmixed as a beverage. The gases do not appear to interfere with the solvent properties of water, at least while cold, and when heated they are quickly disengaged. The changes which take place as to the gases, when brisk pump water is exposed in open vessels, are rather curious. I found that water yielding twenty-six cubic inches, viz., ten carbonic acid, and sixteen azote, &c., when fresh drawn, gave, after standing five hours, twenty-five inches ; the diminution was in the azote, the carbonic acid remaining the same. At the end of nine hours, the total gases, twenty-two inches, one- fourth of the azote had escaped, but very little, not two per cent., of the carbonic acid. After three days, however, the case was different ; no further escape of azote had taken place, the water yielded about fifteen inches per gallon, and of this only from one and a half to two consisted of carbonic acid. The quantity of this gas was smaller than in river or pond water. If these experiments, which I have not had time to repeat, are tolerably correct, they would shew that, on expo- sure to the atmosphere, the azote and oxygen contained in water very soon begin to separate from it ; that after a time the carbonic acid partially escapes, the other gases remaining ; and that this continues until very little carbonic acid is left. The power of water to retain gases in solution depends, the temperature and pressure remaining the same, on the affinity of water for the gas, and upon the proportion of that gas in the superincumbent atmosphere. Those having a great affinity for water fly off in some degree when the gases above the water are wholly different, and those least readily absorbed are retained under an atmosphere of the same gas. Now, these two are antagonist principles in the case before us, azote having little affinity for water, but constituting four-fifths of the sur- rounding common air ; carbonic acid being much more abun- dantly absorbed, but having no atmosphere of its own desscip- tion to press on the water containing it. No calculation could enable us, I think, to ascertain beforehand the order and the degree in which these effects would take place ; that is, to pre- dict the result of these experiments. GENERAL REMARKS ON THE WEATHER IN MADAGASCAR, ANp CHIEFLY AT ITS CAPITAL, TANANARJVOU, From the 27th of June, 1828, till the 1st of January, 1829; with a Meteorological Journal from the 1st of January to the 25th of March, 1829. BY ROBERT LYALL, ESQ. British Resident-Agent, Member of many Foreign and British Societies, &c., &c. [Communicated by Mr. J. F. DANIELL.] TVTE arrived at Tamatave on the 27th June, 1828. During * our residence there till the llth of July, and of four days at Ivondrou, the weather was very warm, and much resembled that we had experienced at Mauritius before our departure. On the journey to Tananarivou, it continued very warm, even during the passage of the great forest, and until we crossed the river Mangoor : it then became gradually cooler ; and, as it was cloudy and windy on traversing the mountain called Augave, (the height of which, above the level of the sea, may be five thousand feet,) it was even cold. Indeed, the change of climate was very remarkable ; and the weather continued cold, not only on the road to the capital, but after our arrival in it. I entered Tananarivou on the 31st of August, on a beau- tiful morning, with a splendid sun. The weather conti- nued very fine, and in the middle part of each day it was warm for a considerable period ; but, as there was no rain, the mountains had a very barren and bleak appearance. East and south-east winds blew hard, almost every evening, and ren- dered it so cold, that, in slender houses, we were necessitated to have recourse to woollen clothes, to a small fire both morning and evening, and to blankets in the night. Excepting a few days, on which it was warm, (as the 12th of August, when his late majesty, Radarna, was interred, and a few hours before and after mid-day,) the thermometer ranged from 50° to 60° of Fahrenheit for a considerable time. On the 17th of August it was windy, and so cold, that we put on our cloaks to go to church. The sympiesometer and the barometer were very little affected, and the medium altitude of the latter may be reckoned 48 Mr. Lyall on the Weather in Madagascar. 25.32 inches. We had neither rain, nor storms, nor even any high winds. The weather, about the end of August, became consi- derably warmer, and continued fine ; the evenings and the mornings were beautiful and highly salubrious, being clear, dry, and cool. Afterwards the thermometrical range became higher, the temperature being generally between 60° and 70° Fahren- heit : now and then, however, for a few hours after the middle of the day, it rose as high as 75° and 80°. Again, when the heat had been less intense in the day, it descended in the evening to 65° and 60° of Fahrenheit. The sympiesometer and the barometer seemed nearly stationary during September and October ; and the wind was regular, at least every even- ing, and blew from the east and south-east. From about the beginning to the 22nd of November we had, now and then, a heavy shower, but no great quantity of rain fell ; so that the Malagash government and people began to fear the loss of their rice crops, in consequence of long-continued drought. They had recourse to their idols, or god?, for assistance, as recorded in my journal of this period. On the afternoon of the 22nd, however, ' a day sooner than the gods predicted,' rain fell very copiously, and continued to do so all night, and even during a part of the 23rd. This date (though afterwards we had some fine days) may be reckoned the commencement of the rainy season in 1828. This remarkable epoch has therefore been late ; but I have been told that it has occurred, though very rarely, that the rainy season has not commenced till January, which must always be a serious misfortune. It has been remarked, that the periodical rain has not followed the usual course — of falling in heavy showers, some time between the hours of two and six o'clock, P. M. On the contrary, it has frequently commenced earlier, and, more frequently, at a later hour ; indeed, it has sometimes rained the whole night, and even in the morning and forenoon we have had heavy showers. Again, after heavy rain-falls, there have been pe- riods of one day, of two days, and even of three days, very fine weather, and without a drop of rain ; but with such heavy dews during the night, as, in the morning, led me to suppose that it had rained. Thunder-showers, which have been fre- Mr. Lyall on the Weather in Madagascar. 49 quent, have generally fallen in the afternoon. The lightning was vivid, and the thunder loud and near, so that a number of lives were lost by the former, in the capital and in its vicinity. Very often in the evening, and especially after thunder-storms, as in Russia, a great part, and even nearly the whole of the hemisphere was illuminated by that kind of lightning (called zara by the Russians) which flashes from cloud to cloud, but never approaches the earth, and by which lives, I believe, are never lost. About the end of November, or the beginning of December, at four o'clock, p. M., a very heavy shower, mixed with large hail, fell, to the astonishment of Mr. Chenard, the tutor of my children, who had often heard of, but had never seen such a * phenomenon.' Ever since the rainy season has set in, with the exception of a few hours before and especially after noon, the heat has been very moderate. The barometer, comparatively speaking, has varied little ; nor has the sympiesometer been greatly affected by the changes of weather. The wind, since the 22nd of No- vember, has been more variable, and frequently from the north, north-west, and west. The quantity of rain which fell previous to the 22nd of November may be estimated at two inches, and that since the 22nd of November at about twelve inches — total, fourteen inches — till the commencement of the report for the month of January, 1829, which accompanies these observations. JOURNAL VOL. I. OCT. 1830. E 50 JOURNAL of the WEATHER, at TANANARIVOU, Capital of e 8 S3 Jan- uary. Baro- meter. Thermometer. Hygrometer. Rain. WIND. Max. Min. Dew Pt. Direction. Force. 1 25 -25 75 66 75 68 •g E Gentle 2 25-25 78 67 74 87 . K & NW Do. 3 25 -30 77 70 74 66 • NW Do. 4 25-28 79 69 76 65 •M NW & W Strong • 5 25-28 74 66 74 68 . E Moderate 6 25-27 74 62 70 68 •65 ENE N Si NW Strong 7 25-32 74 64 70 <;s •28 E & NE Gentle 8 25-28 74 66 68 68 •1 NW Do. 9 25-24 76 68 69 66 NW & W Do. 10 25-25 76 67 68 65 1-5 Ibid. Do. 11 25-28 74 66 69 64 •58 NW&W Gentle with breezes c 12 25-28 75 66 69 67 •80 NWW&E Calm with breezes 13 26-22 79 65 68 65 •45 E and calm Do. 14 25-24 74 65 68 68 •48 Calm, E and calm Gentle 15 25 30 73 64 66 64 •10 Calm,EESE& E Gentle with breezes 16 25'25 73 65 66 64 • • Calm, & E & SE Do. 17 25-34 73 65 66 63 - Calm & E Do. 18 25-33 73-5 65 66 63 1'07' Calm, E NNE & E Calm and gentle with breezes 19 25-32 73-5 66 67-5 64 •27 ENE & calm Gentle 0 20 25-31 72-5 65 67 66 •60 E calm & SW Do. 21 25-28 73 62 63 64 3-20 ENEE&SW & calm Gentle with breezes 22 25-30 73 62 65 65 1-0 E &SW Breezes and squally 23 25-31 73 62 67 65 •76 NNE & E & SW Squally 24 25-29 74 63 69 66 •56 NE &E Calm and breezes 25 25-24 75 62 67 65 •1 NE W & NW Do. 26 25-22 74 64 66 64 1-45 NE NNE & calm Gentle with breezes 27 25-26 75 65 67 64 •8 SE &E 'Do. 1 28 25 -30 72 65 66 64 •15 SE &E Do. 29 25-28 73-6 64 66 64 . E&SE Gentle 30 25-26 72-4 64 66 65 •11 NE E & SE Do. with breezes 31 25-28 73 64-5 66 67 'I Do. Do. MADAGASCAR, for the Month of JANUARY, 1829. 51 GENERAL OBSERVATIONS ON THE WEATHER, &c. Weather cloudy. Weather clearer. Weather cloudy. Wind in the evening, west and strong. Heavy showers, with thunder and lightning. feather cloudy j during the last 18 hours, the wind went nearly round the compass ; heavy showers. Feather clear. Sunshine with gentle showers. Unsettled appearance. /eather in the morning clear, and till noon, with strong breezes. Trifling showers. Heavy dew in the night. Fog this morning. Weather clear. Heavy dew in the night. I Weather clear till 3, then cloudy. Excessively heavy rain in the evening, when the bar, and there was a corresponding fall of the sytnp. Much thunder and lightning. •. sunk to 26° 18'' Weather clear till about 2 P.M., then overcast. In the afternoon rain fell amidst a fog. A good deal of thunder and lightning. f Sympiesometer, 27*72. Weather cloudy, especially after 2. Thunder and lightning, P.M. . -| Temperature, 74'6. (.Barometer, 25 '23. After 2 weather became cloudy. About 5 P.M., partial rainbow In the south-east. Moon obscure in the evening. Constant gentle rain, with heavy showers in the night. Weather cloudy, with clear intervals. Fine day. Rainbow as yesterday. Rain began at 2 P.M. Heavy showers. Moonlight and starlight evening, with clouds here and there. No rain in the night. Cloudy and calm this morning. Clear intervals and showers. Moon Very hazy. Evening darkish. Some thunder and lightning with showers, and fair intervals. Symp. and bar. kept rising all day. In the evening, symp. 27'98. Temp. 65. A uroraborealis in the even- Ing. Moonlight and many constellations visible till 10 P.M., when the whole heavens became obscure ; yet, as was to be expected, no rain fell ; but there was a strong squall. Morning cloudy. Beautiful day. Symp. and bar. fell a little after mid-day. Clear moonlight and starlight evening, and many planets and constellations beautifully seen ; but at half past 9, not a single star was visible. Morningtine. Mid-daysultry and cloudy. At 1 P.M., symp. and bar. falling; at 2 weather overcast; at4, symp. 27'83 ; temp. 71 ; bar. 25-83, when there was a heavy shower with thunder. Weather now fair. Weather cloudy in the morning. Fine from 9 in the morning till 2 P. M. ; then overcast. Symp. fell to 27'94, and bar. to 2u'8 ; heavy shower at 3, then fair weather, alternatefy with thunder and showers. Sheet lightning in the evening. Weather cloudy and sultry ; at mid-day dew point 66 (black ball,) temp. 73. Fall of symp. and bar, trifling; though there were heavy showers. Morning foggy. Weather cloudy ; then clear with sunshine and sultry. At 1 P.M., symp. 27 78, temp. 72'6, bar. 25'26, dew point 62. Heavy showers at 1, 3, and 5 P.M. Rained all night. Now fair with sunshine. Weather cloudy, then fine, and again cloudy. After half past 1 rain began. Very heavy showers In the afternoon, evening, and night, with fog. Now foggy. Weather cloudy, then fine, afterwards overcast, and rain commenced before noon. Thunder in the afternoon with squalls and heavy showers. One remarka trifling. When the wind was at s.w. there were squalls. afternoon with squalls and heavy showers. One remarkable heavy shower. Fall of symp. and bar. " i the ' Weather cloudy, then tine till near noon, when rain commenced. Heavy showers with thunder. Very uai -in, sultry, and oppressive at 2, and afterwards. Weather ve to sink at breezy, and even squally in the afternoon. " Much thunder. Appearance of a" surrounding storm. Conjecture that rain fell at a distance, jry tine from 9 A.M. til!2 P.M. ; then cloudy, and a trifling shower fell. Symp! and bar. began 1 1, and though the day was still very fine, they sunk till 2, when a trifling shower fell. Sultry, Though neither symp. nor bar. rose, weather very fine from 6 A.M. till 1 F.M. , then cloTidy and sultry. Much thunder in all directions, and continued heavy rain with breezes. Fine weather, though cloudy and sultry. Symp. and bar. nearly stationary all day; a little rain. Symp. and bar, ascended in the evening. Aurora borealis in the evening. Weather cloudy, sultry and fine. No rain during day. Symp. and bar. rose in the evening. A heavy shower between 5 and (> this morning. Now cloudy. Fine weather toward 4 P.M., symp. fell to 1V76, and bar. to 25 26, but they soon rose again. No rain. Magnificent starlight evening. Fine weather. Symp. and bar. fell a little in the evening. Heavy shower at 11 last night. Now cloudy, but with indication of fair weather. Beautiful weather. Last twenty-four hours, symp. and bar. varied very little. At 6 this morning a trifling shower. 52 JOURNAL of the WEATHER at TANANARIVOU, Capital of a Feb- ruary. Baro- meter. Thermometer. Hygrometer. Rain. WIND. Max. Min. Dew Pt. Direction. Force. 1 25-31 72 62-3 65 64 •9 E&SE Grentle with breezes 2 25-29 72 63 -2 65 64 . Do. Do. 1 25-29 73 64 67 67 . ENE&E Do. 4 25.29 73'4 61-2 61 57 • • E Gentle 5 25-28 76-2 66'3 68-5 66 • • Do. Do. • 9 25-30 73-5 67-5 67 66 • E& SE Do. 7 25-25 76-6 68-3 69 67 •3 Do. Do. 8 25-22 75-3 64 64-5 61 • E Gentle with breezes 9 25-20 74-5 65-2 61 63 • • E & E by S Do. ([ 10 25-18 77-2 (50-3 61 54 E Gentle during day, strong in the night. 11 25-12 76-4 66-8. 67 64 • • ESE &S Gentle with breezes 12 25'6 76-2 68-5 68 67 •22 SE & NNW Gentle and then strong 13 25-21 75-8 67-4 68-6 67 •36 NNW & NW Strong with squalls 14 25-28 79-3 67-3 67 65 •4 NW N & NE Gentle 15 25-34 73-2 66 67 65 •20 E & calm Do. 16 25-35 72-7 05-5 6S-5 64-50 •1 SE E & NE Very gentle 17 25-34 73-8 62-5 64-65 62 •1 E.E by S&E Moderate 0 18 25-33 73-6 62 -S 64 61 • E Strong with breezes 19 25-36 73-7 62-7 63-5 61 • E Moderate with breezes 20 25-37 73-2 61-8 64 57 . ESE Do. 21 25-35 71-4 60-2 64 61 . Do. Do. 22 25 '37 72-6 60-2 64 63'5 •1 Do. Strong with breezes 23 25-34 74-1 58-4 63 61 . Do. Do. 24 25-34 73-5 61-3 65 60 •1 SE Do. 25 25-34 70-6 61-4 64 60 • ESE Do. T 2rt 26'86 69-8 60-2 63 59 •7 ESE SE & ENK Do. 27 25-34 6ST> 57-3 63 60 . E &ENE Do. 28 25'32 69 -4 57 62 58 •1 ENE Do. MADAGASCAR, for the Month of FEBRUARY, 1829. 53 GENERAL OBSERVATIONS ON THE WEATHER, &c. Weather cloudy. Sympiesometer and barometer nearly stationary. Gentle shower one P.M. Even- ing cloudy. Morning cloudy. Weather cloudy. Symp. and bar. fell a little In the forenoon, but ascended again in the afternoon. Weather fine, but sultry. Symp. and bar. nearly stationary. Sheet lightning in the evening. Weather very line. Symp. and bar. still nearly stationary. Star-light evening, with much sheet lightning. Beautiful fresh morning. Beautiful weather ; yet after two o'clock P.M. the bar. fell to 25.25, and the symp. also sunk. Even- ing line. Much sheet lightning in the evening. A great deal of distant thunder. Conjecture that rain fell at a distance. Fine weather. Beautiful evening. At half-past ten o'clock, when taking an observation of Castor, the whole heavens became covered by clouds. Much sheet lightning in the evening. Fine morning. Fine weather: toward 3 P.M. symp. arid bar. fell, and still they remain low. A trifling shower at half post 9 in the evening. Some sheet lightning in the evening. Cloudy morning. Fine weather. Symp. and bar. rose a little after seven P.M. ; but fell again in the night. Sheet lightning in the evening. Fog between five and six o'clock this morning. Heavy dew. Soon after mid-day, symp. and bar. fell to their present state, though the weather was, and still is beautiful. Splendid evening, with some sheet lightning. Weather continues beautiful, though the symp. and bar. remain low. Sheet lightning in the evening. Weather as yesterday. Symp. fell to 27.54; temp. 76.4; and bar. was depressed to 25. 12 by four o'clock P.M.; dew point 70, black ball ; and 76 covered ball. No rain. Wind south and gentle till four o'clock, P.M., then was NN.W., strong and squally ; and the weather became overcast. Thunder and appearance of storm in the N. and N.W, Star-light evening and night. The quantity of rain which has fallen during the last fifteen days amounts only to iVo- Tne weather has generally been beautiful, and such (as it is said) is rarely experienced at this season of the year. The ground has become arid, and dust is flying about as in the dry season : rain much wanted. Though for the last week, and especially during the last three days, the instruments and appearances lead again and again to the expectation of rain, yet till yesterday evening at half past 9 P.M. we had none. Distant thunder; though little rain has fallen here, I believe much has fallen in the vicinity. The symp. stood at 27.52, temp. 75.20 ; weather sultry. Bar. 25.60. Wind went to the N.W., and was strong and squally at 4 P.M. Dirty appearances. Sheet lightning in the evening. Fine clear weather, with scattered clouds, till four o'clock, P.M., when it rained. Symp. and bar. rising: indeed the latter rose to 25.18, though there were showers last night. Some thunder. Sheet lightning in the evening. Forenoon fine, warm, and sultry. In the afternoon, a good deal of thunder. Weather cloudy. Appearance of rain all round the capital. Much sheet lightning in the evening. Weather cloudy all day. Thermom. at eleven o'clock, A.M. 72'20 ; at noon, only 69'30 ; at one o'clock, P.M., 71-50, in consequence of the fall of trifling showers. Sheet lightning in the evening. Although showers fell in the afternoon, evening, and night, yet symp. and bar. kept on the ascent. The statement of the weather for last ten days merits particular attention. Weather cloudy the whole day : at ten o'clock A.M., drizzling rain, which also took place at different times, but in all was very trifling; yet the symp. ascended to 27.98, and the bar. to 25.38 j after- wards they slowly fell to their present state. Sheet lightning in the evening. Cloudy weather, but fine ; trifling showers, especially about three o'clock, P.M. Fine moonlight and starlight evening. Bar. rose to 25.38, but fell again in the night. Weather fine, and generally clear, with now and then scattered clouds. Morning fresh. Climate, upon the whole, delightful and healthy. Evening moonlight and clear, except at intervals, in conse- quence of rapidly passing clouds. Some sheet lightning. Weather tine, fresh morning ; most agreeable at noon, in consequence of the sun's influence, became very warm in the afternoon ; beautiful evening. Fine morning. Beautiful weather ; splendid evening. Fine weather. Temp, moderate. Sometimes cloudy in the evening. Clear in night. Morning foggy in the east. Fine day; but as the wind was nearly constant, and the temp, never high, at times, rather fresh. Afternoon cloudy. Rain showed itself in the last twenty-four hours. Fresh morning. Shower of rain. Fine agreeable healthy weather. Evening pleasant. Weather continues good ; though part of the last twenty-four hours it was sometimes cloudy, espe- cially in the v.w. : a little rain fell. Wind strong in the night. Cloudy morning, especially towards the N.K. Threatens rain. Weather cloudy, often threatened rain ; but the quantity that fell during the last twenty-four, and the preceding forty-eight hours, did not amount to more than -ji^ of an inch. Still cloudy. Weather cloudy all day, with trifling showers and strong breezes. Fresh. Still cloudy this morning. (Jowl healthy weather, though sometimes cloudy. Ditto, the wind lias varied little for some time past ; the breezes have generally taken place in the night, or with showers. The quantity of rain that has fallen this month forms a great contrast to what fell in December, 1828, viz. 12 inches ; and what fell in January, 1829, viz. 14*02 inches. Aurora borcalis in the evening. 54 JOURNAL of the WEATHER at TANANARIVOU, Capital of | March Baro- meter. Thermometer. Hygrometer. Rain. WIND. Max. Min. Dew Pt. Direction. Force. 1 25-32 70-7 59 63 59 ' - ENE Moderate with breezes 2 25-30 70.2 61 65 64 • • ENE E & calm Do. 3 25-28 74 59 64 60 E & calm Do. 4 25-25 76-1 62 68 66 273 E Do. • 5 25-26 75-4 55 67 65 •60 E & calm Gentle with breezes 6 25-25 72 62 69 66 2-26 Do. Do. 7 25-29 72-4 64 667 66 •48 ENE & calm Do. 8 25-30 71-2 62 67 66 1-33 E NE &E Do. ^ 9 25.28 67-6 59-4 63 66 •68 E calm & E Gentle 10 25-28 71-5 61-4 67 65 1-75 E & calm Do. 11 25.29 71-3 60-4 65 63 .45 ENE&E Do. c 12 25-32 70 62 67 65 1-43 E&NE Moderate 13 25-30 71-3 61 68 62 •73 Do. Do. — 14 25-26 73-8 58 67 67 •01 Do. & NW Do. 15 25'28 73-2 62-4 69 67 . NW Do. 16 25-22 72-8 63 68 66 • Do. Do. 17 25-28 75-6 63-2 69 67 •01 NW&E Gentle 18 25-30 71 60 66 62 •85 Do. Moderate 19 25-30 72-2 61-2 67 65 . NE&E Do. 0 20 25-37 72-6 62 67 64 . E Gentle 21 25-37 72-3 60-5 64-5 61 . E Gentle in the day, strong all night 22 25-35 72-4 59 64 62 . E & calm Moderate 23 25-32 71-8 f>9 0S 63 . Do. Do. with strong breezes 24 25-31 72 60 66 64 . Do. Gentle with breezes 25 25'29 72'4 60-2 65'5 64 t • Do. Do. MADAGASCAR, for the Month of MARCH, 1829. 55 GENERAL OBSERVATIONS ON THE WEATHER, &c. Fine weather, though sometimes cloudy. A Scotch mist for a few minutes. Partial rainbow in th east at 5, P.M. Delightful day, but at times cloudy. Symp. and bar. fell, however, yesterday afternoon, and remain low. Dull morning. Weather as yesterday. Bar. fell T^ and remains at 25 '29. Symp. §ame as yesterday. Aurora borealis in the evening. Symp. and bar. fell after noon, about 2 P.M., heavens became overcast all around, and at 3 a heavy shower fell. Rainbow in the taut ut 5 P.M. In the evening much thunder and lightning, and rain alternating with fair intervals, during which many beautiful coruscations, and much sheet light ning illuminated parts of the hemisphere. Much rain in the night. Foggy morning. Forenoon fine. Sultry. Thunder and lightning. Dark wet evening, except when illuminated b) sheet lightning. Raining heavily at present. Gentle rain during greatest part of the day with heavy showers j much rain in the night. Foggy morning. Weather cloudy, with now and then heavy showers. Atmosphere sultry and oppressive. No thunder Some lightning in the evening. Foggy mild morning. Fine forenoon. Showers and gusts of wind from the N.K. Rained all night, but not heavily. Stil raining gently. The low lands are completely inundated. Fresh and rather cold day. Long continued scattered rain, both in the day and the night. Symp and bar. not much affected yesterday, but have descended a little in the night. Cloudy morning. Cloudy, mild, but disagreeable weather. Surrounding country much inundated. Bad weather. Inundation of the country in some parts very complete. Alarm was sounded at 5 this morning, that the river Kioupa had burst through its banks to the south. The quantity of stagnated water is therefore likely to be much augmented. Symp. and bar. have operated in con- trary direction. Foggy morning. Fine weather and showers alternately during day. Good deal of distant thunder and lightning, Heavy showers in the evening and night. Foggy morning. Showers and sunshine. Pretty good weather in the intervals. Some thunder and lightning. Shee lightning in the evening. Foggy morning. Some distant thunder after 4, just before which there was a smart breeze from the w., accompanied by a trifling shower. Fog this morning. Weather fine, but the plain surrounding Tananarivou is BO inundated as in many places to resemble ponds and lakes. Fine weather. A good deal of sheet lightning in the evening. Notwithstanding the fall of the symp. and the bar. Morning beautiful. Some distant thunder was heard, but only O'l of rain has fallen the last 24 hours. Fog early this morning which has changed to a Scotch mist. Fine weather till 1 P.M., when there was a shower. Symp. and bar. fell. A good deal of thunder and much evening lightning. Heavy rain in the night. Appearance of fair weather this morning. Weather fine and healthy. As the country still is, and is likely to be for some time to come, inun- dated, the air is moist. Distant thunder. Sheet lightning in the evening. Fine morning. Fine weather. Beautiful moon-light evening with some sheet lightning. Hazy in the S.E. this morning. Fine weather continues. Aurora borealis in the evening. Cloudy in the K. and s., but with other favourable indications. Weather very fine, yet when two black clouds passed there was for two or three minutes a Scotch mist. Sheet lightning in the evening. Beautiful day. Sky clear before 6. Cloudy morning. Weather continues charming. No rain last twenty-four hours, notwithstanding fall of symp. and bar. Fine weather. Sheet lightning in the evening. Mr. Lyall had scarcely registered the above obser- vations, when he was made a prisoner at the instance of the gods of Madagascar, torn in a moment from his family and removed to Ambouhipaina, seven miles east of Tananarivou. 56 Mr Lyall on the Weather in Madagascar. GENERAL OBSERVATIONS. 1. TANANARIVOU, the capital of Madagascar, is situated in 18° 56' 20" S. L., and, I conjecture, in about 47° E. L. From barometric obser- vations, I reckon its elevation to be nearly five thousand feet above the level of the sea ; and its highest pinnacle, called Ambouin Sim- boun, about seven hundred and fifty feet above the level of the greatest part of the surrounding plain. I am about to make extensive and more accurate observations respecting some of these points, which I shall not fail, in due time, to make public. 2. In consequence of the peculiar situation of Tananarivou, and especially of its great elevation, a series of well-conducted and well- recorded meteorological observations must be of the highest interest. By the acquisition of additional instruments, and greater practice, I trust to render every month's report more detailed and more interesting than another, until the climate here is sufficiently known. 3. The observations have been made every morning at six o'clock, because this is the only hour on which I could count for regularity : therefore, the day commences at six o'clock, A. M., and ends at six, A. M., of the succeeding day. 4. The sympiesometer used is Adie's, No. 497. 5. In consequence of an accident having happened to one of Newman's mountain barometers (an excellent instrument), I have been compelled to make the foregoing observations with Jones's mountain barometer, which is constantly suspended. In order to have the means of making comparative observations, however, I my- self filled the tube of Newman's barometer, which, though the starting point be somewhat different, acts upon the same general principles and in the same manner as Jones's. The two instruments work together. 6. Rutherford's register thermometer is used for the maximum and minimum. 7. In all my observations with the sympiesometer, after carefully adjusting thejtfewr de lis, I find it necessary to attribute 10, 12, 14, 16, or even more degrees to the mere effect of temperature, between the hours of one or two o'clock and four o'clock, p. M. ; otherwise I should be constantly predicting rain. 8. Daniell's hygrometer is used. 9. I have given a statement of facts, without attempting to draw conclusions. Time does not permit such inquiries ; besides, professed meteorologists will do this much better than I could : therefore, copies of this table, and of that of all future tables, shall be forwarded to my friends, Mr. Dalton, of Manchester, and Mr. Daniell, of London. ROBERT LYALL. ON THE ELUCIDATION OF SOME PORTIONS OF THE FABULOUS HISTORY OF GREECE, BY THE APPLICATION OF THE ANALYTICAL PRINCIPLES OF PHILOLOGY. BY WILLIAM SANKEY, A.M. of the University of Dublin, and ad eundem of Cambridge, &c. TN a former essay I directed my attention to the legitimate L principles which should guide us in the analysis of lan- guages, and applied the same to the investigation of the origin of some of the distinguishing characteristics, as well as apparent anomalies, of the Greek tongue. I would now bring the prin- ciples to bear upon points still more interesting, as shewing us that this is a subject which does not confine its views to the mere mechanism of language, but that it may be advantage- ously employed in enabling us to arrive at the accurate mean- ings of words on the one hand, or, on the other, in throwing light upon the darker ages of history, while as yet dawning through the thick mists of fable. With respect to the assistance we thus derive in ascertaining the appropriate meanings of words, we may exemplify this in the word Xaor, a people, which however, analytically, signifies more accurately a multitude, being obviously resolvable into the radix Xx and oy. Now, Xa is clearly the same as the particle Xa, valde, presenting, therefore, at once, in the com- pound Xst-os-, the idea of largeness. We are also enabled thus immediately to detect the error of the older etymologists, who, being unacquainted with the just principles of analytic philology, deduced Xaos-, a people, from Xa*$-, a stone. Again, to take the particle <$s : this word generally ranked as an adversative, but we shall probably be led to question the justness of this classification when we consider that $e is closely allied in sensible character to £s-o;, ligo, from which it is at once obtained by a direct analysis. The idea, therefore, con- veyed by this particle £e, must be connected with that of bind- ing. This will further appear from its affinity to £si, oportet, which is, indeed, the third person singular of the former verb Sew, the notion of a physical restraint, which is primarily con- veyed by this latter being metaphorically transferred in what is called the impersonal $a, to a moral obligation. Hence then 58 Mr. Sankey on the Philological Analysis it follows that £e should be ranked amongst the conjunctions copulative, and not among the disjunctives, as it has been generally classed by grammarians and lexicographers. Indeed, when we consider the very forced and inelegant construction which, following the present rendering of this particle, is com- monly given to sentences wherein it occurs, we might be apt a priori to doubt whether its proper meaning had been yet assigned. In truth, I believe there will be found but few passages in which the sense would not be much improved by taking $& as a connective, instead of an adversative. I do not, however, deny, but that in some instances it may be used with somewhat of a disjunctive signification. For example, where it is put, as it were, in opposition to /u,sv. Even in these instances, however, the meaning would not be much obscured by rendering £s as a copulative. Perhaps, in such cases, the force of £e might be very well given by the English yet, which is itself derived from the Latin copulative et, and that from the Greek ert, moreover. This view of £s, as a connective, may receive still further support from the consideration that this particle is closely allied in sensible character to the copulative re, the difference lying solely in the interchangeable letters £ and T. Now rs unquestionably signifies and, the same as xat, with which also it is frequently used, xai being put in the former member of a connected sentence, whilst rs occupies the latter. But £s itself is also sometimes used in the same manner after xai. Indeed, in most of those instances in which TE is used, it will be found that &e, according to the laws of enun- ciation, would necessarily be pronounced TE, the £ being changed into r, as occurring after v or a. It is true indeed that £s is sometimes found following after having an apparent connection with tmrnpi a mother, and by the force of a false etymology being supposed to be quasi yn wrnp9 the Greeks have there- upon raised a fabulous allegorical structure. A further confirmation of this view is to be found in the Latin term Ceres, which corresponds to the Greek A*j//.r/?7)p. For Cer-es, as we have remarked before of Kopj, is also mani- festly derived from %zip-u, tondeo. The c, however, of the radix being retained in Cer-es is a proof that its signification is connected with the action of the verb in a present and active energy, whilst the plural termination es shews that this word 60 Mr. Sankey on the Philological Analysis was not originally limited merely to a single individual. Ceres, therefore, analytically and primarily, meant the shearers collectively. So that the terms Ceres, Ksp-w and Core, Kopj, in this respect answer to one another both etymologically and physically, as cause and effect. From this instance we may be led to perceive that much of the Greek mythology, which was almost altogether physical, had its foundation in the radical meaning of the appellative terms therein used. Thus the origin of the numerous fables spread about Pro- teus is at once explained on attending to the real import of the Greek name TIpcJlsios, which being derived from irpaflos, meant the first element ; this, many amongst the Greeks con- sidered to be simple. Out of it, therefore, every thing mate- rial being imagined to be produced by variety of combinations, the fable accordingly took its rise, that Proteus, Ttpuleios, was capable of assuming every shape. Again, the Curetes, Kovpvflef, originally signified the winds, being derived from %opw, verro, to sweep along. In a double meaning of words, and the ambiguity thence arising, originated the fable of Cadmus and the offspring of the dragon's teeth. The history, as deduced from the fable, seems to have been simply this : Cadmus brought with him into Greece many of those improvements which Asia, as ear- lier inhabited, had already made in agriculture and the arts of life. Amongst others he introduced the culture of the avapTov, genista, broom, whose twigs were manufactured into a species of cordage. This plant is of a deep copper or serpent colour. Now, it is remarkable, that the same word Briti in the Hebrew and Syriac or Phoenician languages, signi- fies both a serpent and brass or copper, owing, no doubt, to the similarity in the colour of these objects. Hence, there- fore, it is likely, originated the mistake which gave rise to the fable. For this word ttrnj, having probably been used by Cadmus and his Phoenician followers, in reference to the colour of the broom, it was erroneously interpreted, according to its ambiguous meaning, as denoting a serpent. Hence, the seeds of the broom were called serpents' teeth, which they might themselves also be fancied somewhat to resemble in size, &c. ; and so they were fabled to be particularly the teeth of one of of the Fabulous History of Greece. Gl the larger of those noxious reptiles which, as much infesting the adjacent parts, Cadmus, in clearing the country for his new settlement, had but a short time before destroyed. The ambiguity of the word mraplov, also, which etymologically may signify anything sown, contributed to spread the error. The genista having been sown in drills, as in an oziery, with its upright form and spear-like branches very naturally presented an appearance somewhat like that of a battalion of armed men, to which the imagination would find a still further resemblance in the helmet- shaped carina of its papilionaceous flower. In accordance therefore with this view, the cutting down of the plant for the purposes of manufacture would be represented as a mutual combat amongst the offspring of the dragon's teeth, ignorance, credulity, and fear, coupled with a lively imagination, easily converting the strenuous labours of the workmen into a mutual assault of combatants. The survivor or survivors, as the fable has it, were clearly the labourers employed by Cadmus, who having been at first concealed by the standing broom, and afterwards becoming visible on its being cut down, were imagined to be the remains of the crop of armed men ; and these same workmen, as being his ordi- nary attendants, probably themselves also Phoenicians, further assisted Cadmus in building the walls of Thebes. I am aware that this fable has been otherwise explained, as resting altoge- ther upon the ambiguity above remarked, of the Phoenician word DPI:, which signifies both a serpent and brass, as though the dragon referred to a king armed in brass who was over- come and killed in battle by Cadmus, and the seed of the dragon's teeth to the scattered troops of the slain monarch's subjects, that rose up in arms of the same brazen materials upon his death. That, however, the explanation I have given is more correct, will be evident from the similar achievement of Jason, where we have, besides the account given of the very preparation of the ground for the seed by the labours of the oxen, a circumstance completely confirmatory of its being an agricultural rather than a military exploit. What gives greater weight to the argument derived from this source is the close connection in every point of view between this feat of Jason and that of Cadmus, notwithstanding the interval of time that 62 Mr. Sankey on the Philological Analysis had elapsed between them, and the distance at which Colchis lay from Thebes : for Phryxus, himself a native of Thebes, and born during the lifetime of Cadmus, had probably brought along with him, on his flight from Bceotia, the seeds of [the ffwaplov, the culture of which, as we have seen, had been already introduced into that country by Cadmus. Hence, therefore, the merit of Jason in this particular will consist in the readiness with which he learned the sowing, rearing, and management of this plant in all its stages, as also the skill with which he guided the plough drawn by brazen-shod oxen. For such is the true history, when divested of fable, of the brazen-hoofed bulls ; whilst the panting breathing of the smoking animals, blown with their exertions in ploughing a heavy soil, gave rise to the poetic exaggeration that they vo- mited forth flames of fire. From this view of the history of one part of the Argonautic expedition, I am naturally led to notice another instance, con- nected with another part, where the ambiguity of a name gave rise to a very remarkable mistake. The Argonauts, cut off in their retreat from Colchis through the Euxine Sea by the outlet of the Hellespont, were necessarily driven northwards to the Palus Maeotis, whence, the country about the mouths of the Tanais and the Vistula being probably at that time under water, they were enabled, by transporting their light vessel but a short way across the land, again to launch into the deep. Sailing therefore through the Baltic, and crossing the German Ocean, they passed along the shores of the British Isles. Here it was that, as they discerned the coasts of Ireland, the melan- choly coincidence of a name raised in their superstitious bosoms the most gloomy apprehensions. Informed, no doubt, that this island was called Eirionn or Erin, as it is still denominated in the Erse or Gaelic, the original language of the country, those adventurers connected this appellation with the Greek word Epiwus, a name which, derived from spis, strife, a sinful idolatry had given to the imaginary inflictors of avenging torments. Believing, therefore, that this island belonged to these fancied tormentors, they were appalled at the circum- stance ; and, struck with horror and remorse at the recollec- tion of their conduct towards the Colchians, and the disastrous of the Fabulous History of Greece. 63 fate of Absyrtus, they were naturally filled with the most alarming terrors for their situation. Another instance in which the application of true principles of etymology will be found to afford us much assistance in elucidating history, where it has been obscured by fable, is that which relates to one of the most remarkable of the adven- tures attributed to Perseus. I allude to that which refers to his obtaining, as it was fabled, the Gorgon's head; an adven- ture, as generally narrated, altogether incredible, but which, when properly understood, is highly interesting, as giving us an account of perhaps the earliest introduction, as it would appear, of the coral into Greece, — at least of that species which is called the Medusa's head. It is probable, indeed, that the Tyrians, in their commerce with the Greeks, had brought them specimens of the madrepore, and other coralline produc- tions, at the same time describing the Medusa's head as being of a rarer kind and more difficult to be obtained. A desire, therefore, of obtaining this species, as well as of satisfying an excited curiosity in visiting and exploring strange countries, combined, it is likely, with general objects of a commercial character, impelled Perseus to undertake what may be truly called a voyage of discovery. That he indeed was considered by the Greeks as having first made known to them the coral, and that as one of the fruits of this expedition, is evidently to be inferred from the epithet given to this natural production, the coral) in that line of the poet, where the author expressly de- nominates it, clearly in reference to this very fact, Persean, — — Ilioff'/iioao filivo; (Aiyct, xoupuXioia. The great strength of the Persean coral. It is remarkable, also, that this author, after describing the coral as being originally a vegetable production growing in the depths of the sea, the saltness of whose waters withered its leaves, and so left it, with its branches denuded and bare, to float the sport of every wave, till, thrown at length upon the shore, it indurated on being exposed to the air ; it is re- markable, I say, that he connects the coral with the Gor- gon's head, fabulously ascribing the deep colour of the red coral to the effect of its being tinged with Medusa's blood. 64 Mr. Sankey on the Philological Analysis Now, this explanation, though obviously false, marks the local, or, so to speak, geographical affinity, which was at that time admitted to hold between the coral and the Gorgon's head, and that both were considered to have been obtained from the same place. The truth is, that the error has arisen here from the ambiguous etymology of the name xopaX^wv, or xoup&Xiov. This word, analysed, is evidently a compound of two distinct words, xwpn or xo^-xj, and aXr, mare. Now we have already seen, that the first part, xopj, etymologically signifies the harvest. Hence xoi^aXXtov or xopaXXtov analyti- cally means the harvest of the sea — an expression which, as very happily designating those resemblances of vegetable life which grow, as it were, beneath the bosom of the deep, was a most appropriate appellation for those crops of coral which Perseus brought home with him. The Greeks appear, how- ever, to have been misled here also, as in the fable of Ceres and Proserpine, by the more common acceptation of the word xopn, and so interpreted the compound xoupzXiov, as though it signified the girl of the sea. This interpretation may also have received some further support from Perseus having possibly encountered and slain, in this expedition, one of the native queens of the country which was the more immediate scene of his exploits. We need not, therefore, be surprised that, in conformity with this view, it was imagined that the Medusa coral, with which Perseus, it would appear, adorned the boss of his shield, was the head of a female, as that species of coral bears some resemblance to the human face, especially that of a woman encircled with heavy ringlets of thick curling hair. Even though we suppose the name to have been originally derived from xopy, puella, and from this fanciful resemblance given primarily to this species, but afterwards extended to corals in general, this will still nowise militate against the view I have taken of the origin of the fable, as grounded on the in- troduction of the coral into Greece. Further, from their like- ness to vegetable and animal life, corals were considered as petrifactions ; and hence arose the idle tale, the offspring of superstition and credulity, of the petrifying qualities of the Gorgon's head, and of whole hosts of armies turned into stone immediately on its being presented to their view by Perseus. of the Fabulous History of Greece. 65 If we examine a little also into the origin of the other fabulous circumstances recorded as connected with this adventure, we shall find them also tending still further to confirm the view I have been endeavouring to establish. Thus the wings and talaria with which the supposed Hermes or Mercury is said to have furnished Perseus, clearly signified nothing else than an oared ship or ships with which he had been furnished probably by the Tyrians ; the wings evidently denoting the sails, and the talaria the oars. Even in the etymology of the name Hermes, E/jpcw, we may find, perhaps, a stronger support for this conjecture than at first view might be imagined. The verb Epzaffu signifies to row in particular, and to navigate in general; but verbs in oau are generally derived from, or rather are but other forms of verbs in u or so>. Hence we are led to an obsolete radix, spsu, of the same signification, from which, according to the general analogy of the language, comes E/>/x,-r,s-, the rower, navigator, or, more properly, being originally E/>/>t-ees-, of the plural form, the rowers, navigators. The Greeks, how- ever, naturally enough considered this word to have been de- rived from £/>&;, dico, or perhaps sipoa, necto ; and from this, and the circumstance that the communication between the different parts of Greece and the chief seat of government (which, it would appear, was at that time in Crete or Asia) was carried on by means of sailing vessels, arose many of the fabulous stories related of their Hermes or Mercury. Another etymology might, perhaps, be assigned for this name Hermes, which would no less agree with the main facts of the fable. The radical part of Eppt-m, when analysed, is evidently E/;/x. Now this, written in Hebrew characters, is Din, which, both in the form of the radical letters and the pronunciation, is not very dissimilar to DTH or DTin, the name of the king of Tyre contemporary with David and Solomon. Under this view, then, Hermes, E^/oc-yjy, being of the plural form, would denote the seamen of king Hiram, and so point to the Tyrians as the people who, from their maritime situation and habits, furnished Perseus in particular with the ships necessary for his voyage, as they had all along been the medium of intercourse between the chief seat of government and the provinces of Greece. The chronology, I may also remark, would herein agree with that VOL. I. OCT. 1830. F 66 Mr. Sankey on the Philological Analysis set forth by Sir Isaac Newton, who makes Acrisius, the grand- father of Perseus, contemporary with David. Even, according to the more received chronology, the name Hermes, Epp-ns, may have been derived from a king of Tyre, as the appellation of Hiram, which seems to have been not uncommon among the Tyrians, may have been borne by others of their monarchs, prior to him who was the friend of David and Solomon. However this may be, it is remarkable that the Latin name Mercurius, as well as the Greek, 'E/j/xojs-, seems originally to have been of a plural form, Mercuri, — the terminal us being afterwards added, in conformity with the erroneous notions of a false theology. Hence, whilst the Greeks gave the appella- tion E/5/X7JS-, either from the mode in which these foreigners visited their shores as sailors, or from the name of the monarch whose subjects they were, the Latins, on the other hand, designated them, from their occupation as traders, Mercuri, which word, indeed, considered as a translation of the ambi- guous Hebrew word vys, will at the same time point out both the pursuits in which they were engaged, and their original parentage and country, viz., merchants, Canaanites. This view will be found to agree very well with the various cha- racters ascribed to Hermes or Mercury, so celebrated for elo~ quence and craft, for his skill in mercantile transactions, and readiness in embassage, &c. It is supported also by the fabulous history of his birth, as reported to be the son of Maia. The personal existence of such a female may indeed be well considered doubtful. The name, however, Maia, as derived from ^y.iu, cupio, was obviously directly given, as a very appropriate appellation, to the fifth month of the year, our May — a month so desirable to mortals, after the gloom and nakedness of winter, for the serenity of its skies, the fresh verdure of its foliage, and the richness of its flowery blooms. In the same season > also, navigation, which had been impeded by the raging storms and the roaring seas of winter, was again resumed. As, therefore, these Tyrian or Canaanitish merchant mariners, \3jD, Mercuri, E^/AEE*, generally revisited the shores of Greece and Italy in the month of May, they were allegori- cally said to be the offspring of Maia ; and this, literally taken, was afterwards transferred, as the real origin of his birth, to the of the Fabulous History of Greece. 67 fictitious being Mercurius, who had been made, as it were, their personal representative. To return, however, to the fable of Perseus. I may just remark, in further confirmation of the Medusa's head having been a real coralline production, that Perseus is represented as cutting down the coral with the apww, or sickle — the very in- strument which he is said to have been furnished with for the express purpose of cutting off the Gorgon's head ; but which, in truth, it is clear he had really provided himself with, with a view to this coralline expedition. Many other instances might be adduced, in which an ana- lytical investigation of the names of persons and things throws light upon the history where it has been obscured beneath a mass of fable. Such a view, indeed, of fabulous history, is highly important. No doubt that which is called the fabulous age of Grecian story is deeply involved in thick clouds of obscurity ; yet here and there, through the breaks in the gloom, we can dimly discern forms cast in the same mould with ourselves. It will scarcely be denied, that most of the person- ages which are spoken of as flourishing at that early period did really then exist. The main body of the events in connexion with which their names have been handed down to us, must have had some foundation, in fact, more solid than the mere imagination of the poet, or the fanciful story-telling of the dealers in the marvellous. The early history of every people, except that of the Jews, we find mingled with fable ; and this has arisen, not merely from that love of the marvellous which characterises a rude, untutored race, but also from the want of those faithful records which, by presenting an accurate delinea- tion of events, would, in a great measure, have corrected those popular errors and delusions which have interwoven themselves with the facts. Indeed, there exists at all times a class of persons whose minds are prone to see everything under an exaggerated form, and no less so to communicate their own impressions with additional circumstances of exaggeration unto others. Any person who is at all acquainted with the peasantry, may have observed how distorted a form any more than ordinary event will come to assume among them, as it is con- reyed from mouth to mouth, even in the immediate neighbour- F2 68 Mr. Sankey on the Philological Analysis of the hood of the transaction. Unquestionably, these appendages to the fact will vary much, both in tone and extent, according to the peculiar character of the age and people. Still, we may be certain that facts, orally transmitted, must, through a lapse of time, receive a considerable degree of colouring from the prevailing hues of the various media through which they are transmitted. Many of the leading circumstances may be altered, and not a few may be omitted, whilst some additional ones may be grafted upon the original. The general outline, however, still will have been drawn from fact. Amid all the windings, therefore, and intricacies of the labyrinth, we need not despair of being able to discover the thread which shall serve to extricate us from the maze. It will be found, indeed, I believe, that most of these fabulous legends may in general be traced to — 1. Exaggerated descriptions. %. Mistakes in the reasons and explanations assigned for any particular line of acting, where that was such as might, perhaps, appear extraor- dinary to persons unacquainted with the circumstances and motives that influenced. 3. Allegorical representations of per- sons and events. 4. Metaphorical language ; and 5, as above, ambiguities of words. This last requires no further confirma- tion, after the many instances we have already been consider- ing, in which the foundation of the legend obviously rests upon such ambiguities. In like manner, too, each of the other heads might also be illustrated by appropriate examples, were it not that this would lead us beyond the proper limits of this Essay. I cannot, however, help adducing one which falls under the second head, inasmuch as, though altogether absurd, as at present narrated, it is capable of receiving the simplest explanation ; I allude to the singular tale of the punish- ment of the daughters of Danaus. The solution is clearly this : The perforated vessels which the daughters of Danaus filled with water were evidently clepsydrae, the use of which they had brought with them from Egypt. The Greeks, how- ever, in their then state of ignorance, could naturally enough perceive no benefit to be derived from pouring water into vessels merely for the purpose that it might run out again through holes in the sides and at the bottom ; the more so as this operation, being constantly repeated, seemed as endless as, Fabulous History of Greece. 69 no doubt, it appeared to them unmeaning. Hence, therefore, they imagined it was a retributive punishment inflicted upon these females on account of their cruel murder of their hus- bands. What may, perhaps, add confirmation to this view of the fable, is the fact recorded by Diodorus Siculus respecting the priests of the temple of the false god Osiris in Egypt ; namely, that they filled three hundred and sixty milk bowls every day. Sir Isaac Newton, in his Chronology , imagines that the historian here means that the priests filled each day one bowl out of three hundred and sixty bowls, counting thereby the days of the Egyptian calendar year. Now it is probable that these bowls were clepsydrae, each running for twenty-four hours, thus noting also the time of the day, by being adjusted with something of a graduated scale, according to the descent of the fluid. They would answer, therefore, the double purpose of a diurnal time-piece and of an annual calendar. Taking, however, the historian according to the more obvious meaning of his words, namely, that the priests filled the whole number of the three hundred and sixty bowls every day ; then, if each bowl ran exactly four minutes, and they were filled by these numerous attendants accurately in succession, the entire cycle would be completed just in the twenty-four hours ; so that these four-minute chronometers would give precisely the time of the day. Commencing also every day one bowl lower down, if I may so say, in the order, then the days of a year of three hundred and sixty days would be likewise kept by the number of the bowl with which they began each day. Indeed, were we even unable to assign any probable reason for this custom, still it would serve so far to explain the fable of the Danaides ; inasmuch as, Egyptians as they were by birth, there can be but little doubt but that they carried with them into Greece their Egyptian predilec- tions and Egyptian rites. Hence, therefore, we might natu- rally expect to find some notice, though tinged as it is with fable, of their having adopted this Egyptian custom of pouring a fluid into perforated vessels, and that, no doubt, with the same view, whatever that might be, with which it was origi- nally practised in their native land. ON THE LIMITS OF VAPORISATION. BY M. FARADAY, F.R.S., Director of the Laboratory of the Royal Institution, &c. &c. T WAS induced some time since to put together a few remarks and experiments on the existence of a limit to vaporisation, which were favoured with a place in the Philosophical Transac- tions for the year 1826. When the experiments there men- tioned were published, I arranged some others bearing upon the same subject, but which required great length of time for the developement of their result. Four years have since elapsed, during which, the effects, if there had been any, have been accumulating, and it is the object of this brief paper to give an account of them. The point under consideration originally was, whether there existed any definite limit to the force of vaporisation. Water at 220° sends off vapour so powerfully, and in such abundance as to impel the steam-engine ; at 120° it sends off much less ; at 40°, though cold, still vapour rises ; below 32°, when the water becomes ice, yet the ice evaporates; and there is no cold, either natural or artificial, so intense as entirely to stop the evaporation of water, or in the open air prevent a wet thing from becoming dry. The opinion of many, among whom were the eminent names of Sir H. Davy and Mr. Dalton, was, that though the power of evaporating became continually less with diminution of tem- perature, it never entirely ceased, and that therefore every solid or fluid substance had an atmosphere of its own nature about it and diffused in its neighbourhood ; but which being less powerful as the body was more fixed, and the existing temperature lower, was, with innumerable substances, as the earths, metals, Sec., so feeble as to be quite insensible to ordi- nary or even extraordinary examination, though in certain cases they might affect the transmission of electricity ; or, rising into the atmosphere, produce there peculiar and strange results. The object of my former paper was to shew that a real and distinct limit to the power of vaporisation existed, and that, at common temperature, we possess a great number of substances Mr. Faraday on the Limits of Vaporisation. 71 which are perfectly fixed. The arguments adduced, were drawn first from the power of gravity, as applied by Dr. Wollaston, to shew that the atmosphere around our globe had an external limit, and then from the power of cohesion ; either of these seemed to me alone sufficient to put a limit to vapori- sation, and experiments upon the sufficiency of the latter force were detailed in the paper. The conclusion was, that although such substances as ether, alcohol, water, iodine, &c., could not as such be entirely de- prived of their vaporising force, by any means we could apply to them, but still, if in free space or in air, would send off a little vapour, yet there were other bodies, as iron, silver, cop- per, &c., most of the metals, and also the earths, which were absolutely fixed under common circumstances, the limit of their vaporisation being passed; and further, that there were a few bodies, the limits of whose vaporisation occurred at such temperatures as to be within our command, and therefore passable in either direction. Thus mercury is volatile at tem- peratures above 30°, but fixed at temperatures below 20°, and concentrated sulphuric acid, which boils at temperatures about 600°, is fixed at the ordinary temperature of the atmosphere. It is well known in the practical laboratory that vaporisation may be very importantly assisted so as to make certain pro- cesses of distillation effectual, which otherwise would fail. Thus with the essential oils, many of them which would re- quire a high temperature for their distillation if alone, and be seriously injured in consequence, will, when distilled with water, pass over in vapour with the vapour of the water at a much lower temperature, and, being condensed, may be obtained in their unaltered state. It has been supposed that the vapour of the water, either by affinity for the vapour of the essential oil or in some other way, has increased the vaporising force of the latter at the temperature applied, and so enabled it to distil over; but there is no doubt that if air or any other similar elastic medium were made to come in contact with the mass of essential oil at 212° in equal quantity, and in a manner to represent the vapour of water, it would, according to well known laws, carry up the vapour of the essential oil perhaps to an equal extent, 72 Mr. Faraday on the Limits of Vaporisation. and pass it forward ; only the facility with which the carrying agent is condensed when it consists of steam, allows of the condensation of every particle of the essential oil vapour, whereas the permanency of the elastic state of the air would cause it to retain a large proportion of the vapour of the oil when cold, and consequently a diminished result would be obtained. There are, nevertheless, some appearances which seem to favour the idea that occasionally water favours vaporisation beyond what air, equal to the bulk of the vapour of the water, would do in the manner referred to above ; and it was to ascer- tain whether substances which, from a consideration of the general reasoning already referred to, and the high tempera- ture at which they sensibly volatilized, might be considered as fixed at common temperatures, could have any sensible degree of volatility, in conjunction with water or its vapour, conferred upon them at ordinary temperature. It is well known that a theory of meteoric stones has been founded on the supposition that the earthy and metallic matter found in them had been raised in vapour from similar matter upon the earth's surface ; which vapours, though extremely attenuated and dilute at first, gradually accumulated, and by some natural operation in the upper regions of the atmosphere became condensed, forming those extraordinary masses of matter which occasionally fall to us from above. The theory has in its favour the remarkable circumstance, that, notwithstanding many substances occur in meteoric stones and iron, yet there is none but what also occur on this our earth * ; and it also has a right to the favouring action of water, if there be such an action ; because vaporisa- tion is one of the most important, continual, and extensive operations that goes on between the surface of the globe and the atmosphere around it. In September, 1826, several stoppered bottles were made perfectly clean, and several wide tubes close at one extremity, so as to form smaller vessels capable of being placed within * This very striking circumstance does not prove that aerolites in any way originate from our planet j but then, if we could by other arguments deduce that they were extraneous, it would lead to the conclusion that the substances which have been used in the construction of this our globe, are the same with those •which have been used extensively elsewhere in the material creation. Mr. Faraday on the Limits of Vaporisation. 73 the bottles, were prepared. Then selected substances were put into the tubes, and solutions of other selected substances into the bottles : the tubes were placed in the bottles so that nothing could pass from the one substance to the other, except by way of vaporisation. The stoppers were introduced, the bottles tied over carefully and put away in a dark safe cupboard, where, except for an occasional examination, they have been left for nearly four years, during which time such portion of the substances as could vaporise have been free to act and produce accumulation of their specific effects. No. 1. The bottle contained a clear solution of sulphate of soda with a drop of nitric acid, — the tube, crystals of muriate of baryta. One half or more of the water has passed by evapo- ration into the tube, and formed a solution of muriate of baryta above crystals, but both that and the remaining solution of sulphate of soda is perfectly clear ; there is not the slightest trace of sulphate of baryta in either the one or the other, so that neither muriate of baryta nor sulphate of soda appear to have volatilised with the water. No. 2. Bottle, solution of nitrate of silver; tube, fused chlo- ride of sodium. All the water has passed from the nitrate of silver to the salt ; but there is no trace of chloride of silver either in one or the other. No nitrate of silver has sublimed with the water, nor has any chloride of sodium passed over to the nitrate. No. 3. Bottle, solution of muriate of lime ; tube, crystals of oxalic acid. The water here remained with the muriate of lime. In the tube, the oxalic acid when put in had formed a loose aggregation, with numerous vacancies, and with a very irregular upper surface about an inch below the upper edge of the tube. No particular appearances occur in the vacancies; but at the top there has evidently been a sublimation of the oxalic acid, for upon the crystals and glass new crystals in exceedingly thin plates and reflecting colour have been formed ; these rise no higher in the tube than to the level of the most projecting part of the original portion of oxalic acid ; no appearance of sublimation is evident above this, and it seems as if the most elevated parts of the salt have given off vapour, which has sunk and formed crystals on the neighbouring 74 Mr. Faraday on the Limits of Vaporisation. lower surfaces, but that no vapour has risen to the upper part of the tube. On examining the solution by a drop or two of pure ammonia, it was however found that a slight precipitate of oxalate of ammonia occurred. The experiment shews, therefore, that oxalic acid is volatile at common temperatures, and had not only formed crystals in the tube, but has passed over to the solution of lime. No. 4. Bottle, solution half sulphuric acid, half water; tube, crystallized common salt. No water has passed to the salt. On opening the bottle, the clear diluted sulphuric acid was examined for muriatic acid, but no trace could be found. Hence chloride of sodium has not been volatilised under these circumstances. No. 5. Bottle, solution of muriate of lime ; tube, crystals of oxalate of ammonia. The oxalate of ammonia appeared quite unchanged. The solution of muriate of lime was perfectly clear ; but when a little pure ammonia was added to it, a very faint precipitate of oxalate of lime was produced. No. 6. Bottle, little solution of potash ; tube, white arsenic in pieces and powder. This bottle was opened because of the appearances, in October, 1829, and had then remained three years undisturbed. The arsenious acid was to all appearance unchanged. The solution of potash was turbid and foul. On chemical examination, it proved to have acted powerfully on the glass. It had dissolved so much silica as to become a soft solid, by the action of an acid, and it had also dissolved a con- siderable quantity of lead ; but there was no trace of arsenious acid in it; so that this substance, although abundantly volatile at 600°, had not risen in vapour when aqueous vapour and air was present at common temperatures. No. 7. Was some of the sulphuric acid used in these expe- riments, preserved for comparison. No. 8. Bottle, solution half sulphuric acid, half water ; tube, pieces of muriate of ammonia. When this bottle was opened, the pieces of muriate of ammonia presented no appearance of change ; there was no moisture about them, nor any ap- pearances of dissection that I could distinguish. The diluted sulphuric acid being examined by sulphate of silver, gave no appearances of muriatic acid; so that muriate of ammonia appears fixed under these circumstances. Mr. Faraday on the Limits of Vaporisation. 75 No. 9. Bottle, a little solution of persulphate of iron ; tube, crystals of the ferro-prussiate of potash. Both were un- changed ; there was no appearance of Prussian blue about either the crystals or solution ; neither of the salts had been volatilised. No. 10. Bottle, a little solution of potash ; tube, fragments of calomel. Here the potash had acted upon the glass, as in No. 6; but, with respect to the calomel, the volatility of which was in question, there was not the slightest trace of such an effect. No black oxide nor other substance existed in the potash solution which could allow the presumption that any calomel had passed. No. 11. Bottle, solution of potash; tube, fragments of cor- rosive sublimate. Here the potash had acted on the glass as before ; carbonic acid had also gained access by the stopper ; so that no caustic potash was present ; but there were distinct appearances of the sublimation of corrosive sublimate, and minute crystals of the substance were even attached to the under part of the stopper in the bottle. Hence corrosive sublimate is volatile at common temperatures. No. 12 and 13. Bottles, solution of chromate of potassa; tubes, in one, chloride of lead in powder, in the other nitrate of lead in crystals. In both these experiments the chromate of potash had acted upon the lead of the glass, and rendered it yellow and dim ; so that no indication could be gathered relating to the non-volatility of the compounds of lead. No. 14. Bottle, solution of iodide of potassa ; tube, chloride of lead. Both remained unaltered; the solution of iodide was perfectly clear and colourless ; no trace of the chloride of lead had passed over in vapour. No. 15. Bottle, solution of muriate of lime; tube crystals of carbonate of soda. A part of the water has passed to the car- bonate of soda; but both it and the remaining solution of muriate of lime are perfectly clear. No portion of either salt has volatilised from one place to another. No. 16. Bottle, dilute sulphuric acid ; tube, nitrate of am- monia in fragments. The nitrate was slightly moist. The acid being examined was found to contain nitric acid, whilst the test acid, No. 7, was perfectly free from it. It would 76 Mr. Faraday on the Limits of Vaporisation. therefore appear that nitrate of ammonia is a salt volatile at common temperatures, although it is just possible that slow decomposition may take place in it, and so nitric acid or its elements pass over. No. 17. Bottle, solution of persulphate of copper ; tube, crystals of ferro-prussiate of potash. The crystals had attracted most of the water from the cupreous salt ; but the solution of ferro-prussiate and that of the copper had their proper colour ; neither were rendered brown ; no salts had been volatilised. No. 18. Bottle, solution of acetate of lead ; tube, iodide of potassium. The acetate of lead is now dry ; the iodide of potassium has taken all the water and formed a brown solution, in which there is free iodine ; probably a little acetic acid has passed over and caused the change in the iodide of potassium. There is no appearance of iodide of lead in the tube, but there is in the bottle, and most probably in consequence of the vaporisation of the free iodine from the solution in the tube. From these experiments it would appear that there is no reason to believe, that water or its vapours confer volatility, even in the slightest degree, upon those substances which alone have their limits of vaporisation at temperatures above ordi- nary occurrence, and that consequently natural evaporation can produce no effects of this kind on the atmosphere. It would also appear that nitrate of ammonia, corrosive sublimate, oxalic acid, and perhaps oxalate of ammonia, are substances which evolve vapour at common temperatures. Royal Institution, Aug. 30, 1830. ( 77 ) ON THE EFFECTS OF ELECTRICITY UPON MINERALS WHICH ARE PHOSPHORESCENT BY HEAT. BY THOS. J. PEARSALL, Chemical Assistant in the Laboratory of the Royal Institution. D (URING some experiments, made to observe the effects of an electrical discharge passed over the variety of fluor spar called chlorophane, which is peculiarly distinguished for its phosphorescence when heated, I remarked certain appear- ances, which are detailed in the following investigation. When the electrical discharge is passed over fragments, or the coarse powder of a very fine specimen of chlorophane, a brilliant green light is produced. On repeating the experi- ment many times, I found the phosphorescence re-occurred with each repetition of the discharge, and was even sensibly strengthened by the operation . This striking appearance induced me to suppose that even such minerals as had been deprived of the power of phospho- rescing by calcination might have it restored by virtue of electric action, and led me to make the following experiments, which will shew how far this supposition was confirmed. A specimen of chlorophane, possessing naturally the pro- perty of phosphorescence in a very high degree, was first subjected to the action of heat. The light emitted was co- loured, first bluish-green, very bright ; then pinkish, blending with pale-whiteness as it became red-hot, when it lost all peculiar light. A portion of the same mineral, which had been calcined, and thus deprived of its power of phosphorescence, was then subjected to a single discharge from a small Leyden jar, of about a square foot of coated surface. The substance became luminous during the passage of the electricity, producing a green light. On the application of heat to the portion thus electrized, it was found to be phosphorescent, and to emit a green light nearly as strong as a portion of the mineral in its natural state, with which it was compared. This experiment was repeated, and always with constant results, 78 Mr. Pearsall on the Effects of An inferior specimen of chlorophane was then heated, when it gave out a strong light of a faint purple colour; but it decrepitated so violently during calcination, that a piece of sufficient size to be electrified alone could not be obtained. The splinters were then placed in a glass tube, through which three electrical discharges were passed, producing a deep purple light after each discharge. They were then heated upon platinum, when they evolved phosphoric light of dif- ferent colours, some fragments appearing green, others yellow, the whole finally assuming a deep purple light. These colours were obviously distinct from those of the natural mineral, a portion of which, heated at the same time, shewed only light tints of purple. Part of the same calcined specimen, but not electrified, gave no light when heated*. Chlorophane, whose phosphorescence had been destroyed by an intense heat, was exposed for two days to the sun's rays without effect ; but a single discharge again restored its phos- phorescence. Repeated discharges were made upon the same substance, and it was found that the property was increased by the num- ber and intensity of the discharges, the green light evolved by heat being deeper and of longer duration after three, six, or twelve discharges, than after a single discharge. Chlorophane, which had been heated intensely, and had been since exposed, under ordinary circumstances, to daylight for eight months, had not acquired the least phosphorescence ; but it gave a greenish light during the passage of the electri- city, increasing with the strength of the discharge, and was afterwards luminous by heat t- A crystal of purple fluor spar, calcined at the same time, « The mode I adopted was to heat the portions of mineral upon a platinum capsule, covered by a watch-glass. The phosphorescence was thus rapidly pro- duced, and easily governed by the regulated flame of a spirit-lamp. The identical fragments were also readily submitted to repeated examinations ; and I conceive that by using platinum instead of iron, as usually recommended, I guarded against the introduction of matter which might have interfered in the experiments. The calcinations were performed in a crucible at a red heat. •J- Dr. Brewster exposed specimens to the sun's rays concentrated in the focus of a lens, but without the slightest indication of returning phosphorescence. — BaEwsiJSR on the Phosphorescence of Mineral*. Edin, PhU, Journal, i, 387. Electricity upon Minerals. 79 and similarly exposed to ordinary light, did not phosphoresce when heated, until it had been electrized, when it was faintly luminous, with a deep-purple light. Apatite was then experimented with, and likewise deprived of its phosphorescent property by calcination ; but, upon electrifying it, and applying heat, it was found to have re- sumed the power, and evolved a lemon-coloured light, which rendered the figure of the fragment distinctly visible. With apatite, as well as with chlorophane, the light repro- duced was in proportion to the discharges made. A fragment of apatite answers better than the mineral powder. These experiments proved, that the phosphorescent pro- perty, when destroyed by heat, can be restored by electricity to minerals which had thus been deprived of it. I was therefore led to investigate how far other mineral substances which phosphoresced by heat could have this pro- perty increased and restored to them ; and also whether some substances, which did not possess this property naturally, could have it imparted to them by electric action. The following experiments were accordingly made: — A colourless variety of fluor spar was tried, which gave not the least indication of light when heated ; but after six dis- charges had been made from the Leyden jar, it was capable of evolving a beautiful flame-coloured or orange light. In this case, the property was conferred upon a substance which pro- bably never possessed it previously. The experimental results obtained with other specimens are given in the form of a table, under the respective heads. 80 Mr. Pearsall on the Effects of Effect when Re-heated. Faint light. Momentary light, but distinct. 1 Faint light. Light faint violet-coloured, I ending with deep purple. ii '3's fi iil i J| |1 u o Light orange colour — bright, 1 short duration. § 1 B Greenish yellow light. 5 •1 1 li il D3 i I •9 ^ "S il Ditto. Orange light, — required high temperature. 1 ft, J * I* _3 ^n ^ • A +• 1 90 3 * | 1 1 1 1 !l .8 ;g JS "S ^3 '-3 09 2 s 'w f 1 g 1 ^3 W bp -4-i x -2 r2 *^5 1 -S" -2^ 1 : .8 '^d 1 1 1 1 8 1! 6 cc S 1 1 Q 1 02 Cfi 'I c» £& IS o % Calcined. ~OT 3 3 Q S o •1 5 Q _o 1 n § I I o C3 6 a I 2 "1 O) Q i 1 * .13 1 Jgi fi "o P ^ _2 o fe ^ ~u W V At ^r 32 "So ;5 o tscS 'o i i =i H3 1 * . 1.-3 ^ 1 "Sa . '> ^ i *>£ ^ "? to • 4j*i'l H ^ o o *« bC ^£3 "5 5 g 6 O o £9 -2 c5 QJ o _ ^*J 3— •^ r^5 bo Jo ^ ^j •C o ."ti ^ ^ £ Q Q 6B 3 02 o s Q S w •5 I r'. . rt • r3 W . . ^^ M "S a B rt 2 o •2 f-H U w , 1 .' 1 1 *8 ! 2 I- 1 1 ' White crystalliz S '-« 1 3 3 Q S ! Green crystals. 1 I s •a B j if i* ti I* Another specii dark purple. J jj fr 5 "2, So £| 1 0 M . j | S 5 5 * 5 5 * S * 5 H ij S R « e$ co ,- <0 00 » 0 rH « 3 C4 eo i— 1 r— I Electricity on Minerals. 81 In these, as well as in the preceding experiments, portions of the same calcined mineral, but not electrified, were heated at the same time ; but in no instance did the non-electrified sub- stance evolve light. In this table, it will be observed that Nos. 1, 2, and 3, did not possess light in their natural state, but light was imparted to them by electricity. No. 4 possessed alight of a faint colour, which became whiter as it was heated, but its conferred light ended in purple. Those numbered from 5 to 10 had light restored to them, which differed, however, in colour from their previous natural phosphorescence. 11 and 12 had light given to them. No. 13 had light restored to it. I now proceed to some remarks on colour given to fluor spar by electricity. In some experiments with the white fluors which had a yellowish tinge, it was observed that, after the powder was electrified, or when six or seven discharges had been made through a piece of the mineral, that a difference was perceptible between the electrified and the natural mineral, the electrified substance having a bluish tint, whilst the other was white. The phosphorescence was also stronger, where the tint thus given was most obvious. As the colour had been most decidedly given by electricity to some portions of a crystallized mass of dark compact purple fluor, which had been rendered colourless by heat, some white pieces were selected and broken ; one portion had twelve dis- charges passed over and through it, which produced a light blue colour, very decided upon the edges and angles of the laminae, especially toward the exterior. Both fragments were then heated ; that which had been electrified gave a pale blue light of short duration, and, when cold, had lost its blue tint; the other portion evolved no light. The fact, also, was well shewn by confining the electrical effects to one extremity of a colourless portion ; a perceptible tint was caused by a few discharges. Some splinters and fragments were placed in a small heap, inside a glass tube, open at both ends, and between the two ends of the wires of the discharger, which were about an inch apart, VOL. I. OCT. 1830. G 82 Mr. Pearsall on the Effects of and likewise introduced into the tube ; after several discharges had been made, most of the splinters had acquired a blue tint ; when heated they evolved a strong light of a pale yellow colour. Larger pieces electrified, assumed a blue tint, giving also a blue light when heated ; but when these pieces were crushed into small fragments, electrified in the tube, and then heated, they evolved a pale yellow light, as in the preceding experi- ment. In some instances, however, fragments gave a light, at first blue, afterwards changing to a straw colour ; but in every repe- tition the colour and intensity of the light differed according to the size of the specimen, as in the above examples. The blue tint caused by electricity seemed to be superficial, or nearly so; for when some coloured portions were broken, they were colourless in the interior, but tinted upon the external edges. The colourless parts were not phosphorescent, while the coloured and exterior parts were. So that it is probable that the phosphorescent property is also conferred principally upon the superficies, which may be the cause of the differently- sized pieces evolving differently-coloured light. To avoid any fallacy from the transfer of metal from the wires, and its oxidation by the electrical explosions, experi- ments were repeated, and the discharges were made from platinum points, with the same resulting blue colour as before. Other substances were then examined, which, however, pro- duced nothing immediately bearing upon the preceding experi- ments, excepting, however, that it was found that, by passing twelve discharges through a diamond, it afterwards evolved a pale blue light when heated ; it had been made red-hot previous to electrization, but without effect. Two other diamonds gave no light when heated, until from twelve to twenty discharges had been made over them, when they, also, gave a pale blue light by heat. Diamonds probably vary in respect to this property ; for a cut diamond gave no light, neither could any be imparted to it by electricity; whilst, on the contrary, another diamond was found slightly phosphorescent by heat, shewing feebly a pale bluish light ; and this specimen, when electrified and again heated, gave a stronger blue light than any other diamond. Electricity upon Minerals. 83 An amethyst, sapphires, rubies, and garnets, with many ordinary mineral substances, gave no indication either of natu- ral or acquired phosphorescence. In conclusion, I may be allowed to remark, that I am not aware that the phosphorescent property has ever been restored, or imparted, to this class of bodies, by any other means. Note. — The consideration of other varieties of fluor, and the duration of the effects, as well as other circumstances bear- ing upon the preceding facts, may form the subject of a future communication. ON THE DEVELOPMENT OF THE SEVERAL ORGANIC SYSTEMS OF VEGETABLES, with reference to their Functions ; and especially on the Respiration of Plants, as distinguished from their Digestion. BY GILBERT T. BURNETT, ESQ. TN no subject has indeterminateness, arising from conflicting dogmata, prevailed in a more perplexing, in a more dis- heartening degree than in the general philosophy of life, and particularly in the physiology of plants. At one time even vitality was denied to exist in them : their curious structures and still more curious functions being all considered as merely mechanical and chemical phenomena. When subsequently their vitality was proved, the reaction perverted the very truth that it established, by attributing to simpler plants the organs of the more complex animal frame : thus we hear of the arte- ries, the veins, and the nerves of plants ; of the uterus, the vagina, and the testes: the roots have been declared lacteals, and other parts placental vessels ; the leaves have been con- sidered lungs or gills, and in their functions sometimes they have been compared to kidneys: again, the wood has been esteemed the osseous compages of the plant, and the pith, its spinal marrow, or the centre of its nervous system ; which last idea introduced the absurd doctrines of the instincts, sensation, and perceptivity of vegetables. Nay, when not even a sem- blance of parallelism could be either found or feigned, as was G 2 84 Mr. Burnett on the Development the case with the stomach and the heart ; then by a licence still more exceptionable, analogy and affinity were confounded with eacli other, and all deference both to structure and to function disregarded ; for in this instance heat was regarded as the heart, and the earth as the stomach of plants. Simi- larity of function is often found, however, to be a far less erring guide than similitude of external form and structure ; the one is more general and less modified than the other, for very diversified means may be adopted to achieve the self- same end : thus nutrition may be performed without a mouth to receive, teeth to chew, or even a stomach to digest the food ; respiration may take place without either lungs or gills ; pre- hension without either hands or claws ; and progression with- out wings or feet. Thus among plants, although the root may in general be the prime organ of nutrition and the seed of reproduc- tion, many plants are efficiently nourished and propagated without either root or seed ; at least without those modifications of the nutritive and reproductive systems being present, which are ordinarily so called; the functions remaining when the organs have disappeared, i. e., the ends being still the same, though the means have been greatly varied. From these cir- cumstances such plants have been called imperfect plants; yet this has been only done, because they have been imper- fectly considered ; and still more, because the abstract idea formed by many phytologists of a seed or of a root, has been rather the amplification of the idea of some particular seed or root, e. U> to that of the patio, which, he says, in p. 91 of the work, 'has subsisted two centuries and a-half, and will subsist as long as the world endures.' f ' Metal de Ayuda' — Ore of a more fusible character, mixed with the less tractable ores to assist their fusion. J ' Plomillos' — Scoriae charged with lead. $ « Fierros' — Slag or scum, being an unreduced mass of oxides and sulphurets, in which those of i/w predominate, 144 Commentaries on the some of clay. In some the smelting is performed with wood, in others with charcoal ; in some the mouths or apertures are stopped up, and in others left open. In some, the ore and wood are mingled together ; in others, the wood or charcoal is not in contact with the ore, but the flame only, whence they are called reverberatory furnaces/ * Of the smelting of Ores. — Having made the proper mixture, and prepared the furnaces and the machines for supplying them with wind, the smelter must heat or anneal the furnace, if, from being new or newly repaired, it requires it ; for, if the ore be thrown in whilst the furnace is cold, it is apt, upon getting warm, to fly or crack, with danger to the bystanders: and if it be moist, in the summer, the same thing will happen, and it will explode with very great force. During the first few hours, charcoal is first thrown in, then a basket of slags, then one of charcoal, and so on, until it be time to add the mixed ore. Haifa basketful of this is then thrown in, and upon that a basket of charcoal, and so on, until the furnace begins to work, after which, alternate basketsful of mixed ore and charcoal are thrown in. One or two cargas of charcoal are con- sumed for each charge, according to the nature of the ore ; some ores requiring the furnace to be moderately filled ; others, that it should be filled to the top. If the ore be not earthy, but clean, the furnace may be charged freely. ' The furnace being thus arranged and brought into play, smelts four charges in twenty-four hours, the ingots being tapped off from time to time ; for which purpose, an aperture is made below the bridge of the breast-pan, and the melted portion runs off into the float. The first ingot let off, after repairing the furnace, is called calentadura, and is smaller than the others, because the furnace becomes coated with vitrified ore adhering to it, and care is there- fore taken not to throw in rich ores for the calentadura. The fused metal being let off, the bridge is stopped up, the breast-pan is cleared out, charcoal dust is thrown into and around it, and the furnace is again set to work. The portions which may have adhered to it are taken off last of all, and are mixed with the ores in future smeltings. * After the smelting is performed, the furnace is uncharged, which is done in the following manner. The charges of ore being all finished, slags and charcoal alone are thrown in, until all the smelted ore has flowed into the breast-pan, when the furnace throws oft' a very beautiful flame. The wall of mud bricks and everything which may have adhered to it, are then broken down with a crow or iron bar of about twenty-five pounds weight. And here the unfortunate smelters suffer much, during an hour of great labour ; for the furnace is hot in the extreme, the crow is heavy, and the incrusted matter adheres very closely. The smoke and vapour from the slag, which are quenched by pouring water upon them, and which are consequently carried down to the feet of the Mining Ordinances of Spain. 145 workmen, are poisonous ; and as they drink water incessantly to relieve their exhaustion, they lose the use of their hands and feet, and become bloated. They are subject also to violent pains in the stomach, occasioned by the coldness of the ore.' After describing the mode of refining the silver, the author proceeds to describe the operation of cold amalgamation, or amalgamation by the patio, by which the greater part of the gold and silver now circulating over the whole globe has been reduced from the ore. ' Of the reduction of Ores by Quicksilver. — Nature, by exhibiting to mankind the effect of fire in fusing the surface of mountains, first suggested to them the idea of smelting the ores containing lead. Nature also, by setting before them the particles of quick- silver found amongst the ores, first guided them to the method of mixing the harsh ores with quicksilver, salt, and water ; an opera- tion which, although in the infancy of the discovery rude and troublesome in practice, requiring many months to effect the reduc- tion of the gold and silver, has now, by the devices of art, and the lessons of experience (the best instructor in the hidden mysteries of physics), been carried to perfection ; magistral* and various other mixtures being employed, so that the ore may be reduced in twenty days or under — and the process has even been completed in twenty, four hours. * The object of first importance, in the process of amalgamation, is to provide a skilful amalgamator, capable of distinguishing be- tween smelting ores, and those adapted for amalgamation ; who can make assays, in the small way, to ascertain what the monton will yield in gross ; who understands the proper ingredients, tem- peratures, admixtures, and stirrings to be applied, and who can calculate and compare the probable amount of the expenses and of the metallic produce: for the bringing the silver to the proper point is not to be entrusted to a mere ignorant blockhead. 4 Secondly, a due selection of the ores must be made, for the purpose, in performing the reduction by amalgamation, of making such mixtures as their nature may require ; and such ores as require smelting, must be set apart for that operation. * Third, the ore must be ground as fine as possible, that the quicksilver may combine more readily with the silver. * Fourth, the ore being ground, it is the practice, in some dis- tricts, to roast such as is of a sulphureous or bituminous (?) nature, in furnaces adapted for that purpose ; in which the criterion of being sufficiently purified, is the ceasing to give off vapour. The same treatment is also applied to the pyritous or resplendent ores, which, under the influence of fire, lose their splendour, and at the same time, get rid of their prejudicial qualities. Those which contain * Sulphuret of copper, roasted and ground to powJer.— Trans. VOL. I. OCT. 1830. L 140 Commentaries on the litharge or copperas should not be roasted, until they have been washed and thoroughly agitated in tubs of water, so as to separate the copperas ; for unless this precaution be taken, it will be increased in quantity by the action of the fire, instead of being driven off, and it will have the effect of destroying the quicksilver, and preventing* its uniting with the silver. It is sometimes proper to roast the ore after grinding, and sometimes while in the rough. But the most usual course, in the mining districts of New Spain, is not to roast the ore at all, on account of the injurious effect of the operation, in rendering it dry, in diminishing its richness, and in augmenting its bad qualities. * Fifth, the ore being ground, is thrown into heaps or montons, usually of 30 quintals ; but in some places of 18 quintals: and the montons are sometimes placed beneath a roof, but most frequently in a well-flagged yard or patio, whence this mode of reduction is called the reduction by the patio. * Sixth, with each monton of 18 quintals, are mixed two barrels of brine, from impure salt; six, eight, or ten pounds of magistral, as the nature of the ore may require, and from ten to twelve pounds of quicksilver. The monton thus prepared, is stirred and trodden, which is called repasar. After two or three days, the stirring and treading are repeated, and if it require more quicksilver, a further charge is thrown in, and it is again stirred, until found to require no more : and it is to be observed, that the more quicksilver it requires the better, as a proportionate quantity of silver may be expected. * Seventh, the quicksilver must be added at different times, and not be thrown in all at once, so that it may by degrees take up the whole of the silver. The first stirrings must be performed with softness and gentleness, lest the quicksilver should become too minutely divided and form Us, which is the term applied when it divides into almost imperceptible particles. From the varying na- ture of the ore, and the diversity of circumstances which arise, no certain rules can be laid down for the course to be pursued in stirring in the quicksilver and magistral, and it will therefore be found, that it is sometimes necessary to excite heat by stirring, and at others to apply moisture. Neither is it possible to determine the precise moment at which the montons are in a state for washing, for though they may not make any Us of silver, nor require any more quicksilver, yet the quicksilver may be dispersed. The only rule is, to ascertain whether the proportion of silver taken up, cor- responds with the result of the assay made at the commencement of the process ; and there is no way of ascertaining this, but by making a further trial, in a small way, whether the monton is in want of any addition, which in such case may be supplied, or whe- ther it is complete, in which latter case the monton may be washed. 4 Eight, the monton being ready for washing, is thrown into wooden Vats of very large size, within each of which is contained a Mining Ordinances of Spain. 147 mill. The mill is turned by a mule, and it is proper that it should not always go round in the same direction, but that the motion should be sometimes reversed : the object being-, that the Uses of silver may fall to the bottom, and that the quicksilver contained therein may not be lost by escaping with the slime or earthy residue, which contains a proportion of silver, and also of quicksilver in a minute state of division. To prevent this loss, it is therefore neces- sary that the mixture should be kept briskly stirred in every part. The slime being separated, the quicksilver remains at the bottom of the vat, combined with the silver, in which state it is called amalgam. The amalgam is taken out and placed in a linen bag, which being suspended from the beams, the uncombined quicksilver runs out. The part which remains in close combination is made up into small cakes, which are formed into one large cake or pina (pine apple), the size being adapted to the capacity of the brass cap or bell. The latter consists of two pieces, the first of which is in the form of a large basin, with a groove round the rim and a hole in the bottom. On the inner part of the rim are three rests, on which is placed a grating, made of iron bars, and upon that is set the pina or cake, which is covered over with the cap. The cap is bell-shaped, and fits into the groove of the vessel, which must be surrounded with earth, and have a pan of water beneath it. The cap or bell remains above, and is covered entirely with ignited charcoal, the heat from which, raising the quicksilver in vapour, it finds its way into the vessel, and passing through the hole in the bottom, is received in the pan of water, and brought back into the state of fluid quicksilver. Where caps of brass, copper, or iron, cannot be procured, they must be made of the finest clay, adapted to resist the fire. * The proportion of silver returned, depends on the quality of the ore ; sometimes the produce of silver is equal to an eighth part of the quicksilver mixed in with the monton, sometimes a sixth part, and sometimes a fifth part. The quicksilver separated in a liquid state, still contains minute particles of silver, and it is set apart to be used in working other montons, until consumed. This is the only part really consumed ;* for the rest is either lost by being converted into lis in the montons, or escapes with the slime, from the agitation of the mill, being divided into the most minute and imperceptible particles. A quintal of quicksilver is not wholly consumed until after it has been employed seventeen times.' "When the ore is tolerably rich, and a more speedy return of the silver is desired, another process is sometimes resorted to> which is called the beneficio por cazo, or reduction by the cazo. * In Mexico, the difference between the quantity of quicksilver employed in the process of reduction and the quantity recovered, is arbitrarily divided into quicksilver consumed and quicksilver lost; a quantity equal or proportionate in wi-ijrhtto the silver obtained, being said to be cowswrwct/, and the remainder of the dciicient quicksilver to be /wiV, — Trans, It* 148 Commentaries on the This process has the advantage of wasting very little quick- silver, and is thus described : — * Reduction by the cazo (pan). — This method of reduction affords the most speedy means of extracting the silver. The ore being tho- roughly ground, and a quintal being taken, the proper quantities of salt, water, and quicksilver, are mixed in, according to the nature of the ore. The mixture is then placed over the fire, and must be kept constantly stirred, and the act of ebullition further assists in keeping it in motion. It is tried from time to time, to ascertain whether it requires any further addition of quicksilver or salt. Each pan will reduce three charges per day. If the ore be rich, it will often yield a marc, a marc and a half, or two marcs per quintal : and provided the quality be not lower than six ounces, this mode of reduction is very advantageous ; but if the produce of silver be below that rate, it will not answer, from the great consumption of wood, quicksilver, and salt, together with the cost of the pans and coppers. The latter must be closely attended to, to see that there are no chinks or cracks in the bottom, through which the quicksilver might escape; to prevent which, they should be varnished with several coats of lime, slag, iron, and white of egg, well beaten up together. Barba expresses himself in highly approbatory terms of this method of reduction, both on account of the saving in quick- silver, and because fuel may be supplied from various trailing plants, which abound in the Indies, and may likewise be much economised by making one furnace heat four pans, as we have seen in several sugar mills in the kingdom of Mexico. 4 The assays in the small way will indicate, exactly, what quantity of silver the boiling should yield ; but this is more readily ascertained by inspecting the substance itself, which, being taken out with a ladle, and the slime being separated, the metal remains. The slime is separated by washing, in vats of water, supplied from a cistern appropriated to the purpose. This operation removes all the earthy matter and slime ; which, when a sufficiency is collected, are worked over in the process of reduction by cold amalgamation. The quicksilver settles, and is found at the bottom of the vat, com- bined with the silver. The quicksilver is then separated, in the manner described under the head of reduction by the patio ; but it always requires refining, never turning ont pure, like that from the patio.1 A third method depends on the employment of sulphate of copper, or colpa. This process, called the bcneficio por colpa, is as follows : — * Of the reduction by colpa (sulphate of copper.) — The plan or sketch of the new method of reducing the silver from all classes of ore, whether cold or warm, by means of colpa, or white or yellow copperas, was described by Don Lorenzo Phelipe de la Torre Barrio y Lima, a proprietor of mines in the district of Mining Ordinances of Spain. 149 San Juan de Lucanas in Peru, and was printed at Lima in 1738, and reprinted at Madrid in 1743 ; where a summary of the dis- covery was likewise printed separately, in the same year, which met with commendation from the pen of Father Feyjoo*. The discovery consists in employing colpa, or copperas ; the goodness of which is tried by reducing it to powder, moistening it with water, and throwing some globules of quicksilver into it. If the quicksilver spreads, or separates into minute particles, the colpa is good ; and the like if the quicksilver, when placed on the colpa, and stirred in a cup or with the finger, assumes a bluish ash colour, or divides. * The ore and the colpa being well ground, the latter is to be taken in an equal proportion to the salt used. The mixture is to be stirred, as in the ordinary process of reduction, four times a day, and is afterwards to be charged with about two quintals more of the colpa, and water is to be sprinkled uniformly over it. The quicksilver is then to be stirred in, in such quantity as the nature of the ore may require. After six days an assay is made, the stirring being continued ; and if the ore be too warm, it is allowed to cool, or lime is thrown in ; after which fresh charges of quicksilver are added from time to time. The slime must be washed without throwing in any quicksilver by way of bano^. When the quick- silver is driven off, it will be found that a greater proportion of silver is obtained, and that none of the quicksilver is consumed, except such part as is lost in the stirring, or from other accidental circumstances. This is the method pursued with the cold ores. « ' For the warm ores it is said, that when ground, a basketful of lime is to be thrown uniformly over them. To twenty-five quintals of ore, ten arrobas I of salt are to be added, with a sufficient quantity of water, and the mixture must undergo four stirrings. The next day, the colpa, being first well prepared, is to be added, in the proportion of one half, to the weight of salt used ; and a sufficient quantity of water being added, the mass is to be stirred four times, and as often on the following day. The mass being spread abroad, another arroba of colpa is to be thrown in, distributing it uniformly, and the mixture is to be sprinkled with water. When thus moist- ened, the quicksilver is to be stirred in; and three da\s afler, it must be ascertained, as in the ordinary mode of reduction, whether the montons are cold and require more stirring, or whether they are warm, and demand a further addition of lime.* Other methods of reduction are likewise described, which, being in less general use, we pass over. When on the subject of boundaries, the author describes, at * Cartas eruditas, torn, ii., carta 19. f A term applied to a supplementary proportion of quicksilver, usually thrown iu by way of softening the slime preparatory to washing. — Tnins. £ An arroba is 2i>ibs. Spanish. — Trans. 1 50 Commentaries on the some length, the method of mine-surveying practised inNew Spain, and the simple instruments employed for that purpose ; and he takes occasion to recommend the adoption of the me- thod then practised in Europe, which he illustrates by descrip- tions of the instruments, figures, and diagrams. (Vol. i. p. 327, &c.) The latter method being, in principle, though not in all its details, the same which is now pursued in the Cornish mines, it is unnecessary to refer to it more particularly. The various machinery employed in mining and the reduc- tion of the ores, is also described and illustrated by faithful, though rude figures. (Vol. ii. p. 189, &c.) In another part of his work, the author discusses the expe- diency of opening the quicksilver mines of New Spain, and the probability of their admitting of being worked with advantage. The trade in quicksilver being monopolized by the crown of Spain, no mines of that metal were allowed to be worked, but those of El Almaden in Old Spain, and Guancavelica in Peru, and hence no progress was ever made in turning to advantage the quicksilver veins of New Spain. But that there are such veins, and that they might be worked to much advantage, is evident from the following passages: — ' In stating above, that we have not met with any account of mines of quicksilver having been worked in the early times after the discovery of the kingdom of New Spain, we are to be under- stood as referring to the sixteenth century, the era of the conquest; but subsequent to that period, many instances may be found. 'First, some quicksilver mines were discovered in the jurisdiction of Chilapa, at sixty leagues distance from Mexico, to the southward*. Don Gonzalo Suarez de San Martin went over in August, 1676, to explore these mines, with a master smith and master bricklayer, and having set up a shed, a house, a smithy and furnaces, he had a part of the crest of the vein blasted away on the 14th of October, and commenced the works of San Mateo, San Joseph and Santa Catalina, all contiguous. He began three adits at a greater depth ; but the hardness of the ground obliged him to remove half a league farther down, where, finding fair indications of success, he drove the work of la Concepcion. Here also he found very good ore, in a matrix of white spar, and drove a work, which he called los Reyes. He then drove an adit in a cross direction, and, at the distance of 47 varas, cut a vein of considerable size. Several assays were made of the ores from these works, both in the large and small way. Those from San Mateo yielded, by the minute assay, 12 ounces of quicksilver per quintal, those from Concepcion 25 ounces, those from the cross-cut 26 ounces. * Villa Senor, Theatro Americano, torn, i., page 178. Mining Ordinances of Spain. 151 * The second instance was during the viceroyalty of the Duke de la Conquista, who, in the year 1740, commissioned Don Philip Cayetano de Medina, an alderman of Mexico, and proprietor of the estate in which the Cerros of el Carro and el Picacho were situaU-d, and Don Gregorio de Olloqui, an inhabitant of San Luis Potosi, to inspect some quicksilver mines in the aforesaid Cerros, which, according to Don Mathias de la Mota*, are in the jurisdiction of the Sierra de Pinos, in the kingdom of New Galicia. The result of this commission has not become known. * The third instance is that stated above, as having occurred in respect to these very mines of el Carro and el Picacho, in the year 1745, when the working of a newly-discovered mine of quick- silver was taken up by Don Fermin de Echevers, the president of Guadalaxara. On this occasion, we know from very good authority, that the vein was found to be rich, abundant, and easily worked, and equal to the supply of the whole kingdom of New Spain ; and also, that upon the result of the reduction of some of the ore, con- ducted under the president's orders, the cost of the quicksilver amounted to no more than 22 or 23 dollars per quintal. * The fourth instance we shall mention, occurred previously to the last, being in the year 1743, early in the viceroyalty of Count Fuenclara, by whose order doctor Pedro Malo da Villavicencio, senior judge of the royal audiency, set out for the purpose of exploring some other quicksilver mines near Temascaltepec, the ores of which had been subjected to several experiments and assays at Mexico, by Don Manuel de Villegas Puente, factor of the royal stores, who now accompanied the senior judge ; but their investigations failed of any beneficial result, and it appears that nothing but urgent necessity will ever induce the government to sanction the laws permitting mines of quicksilver to be worked, like those of silver, gold, or any other metal. * Yet, as it is evident that there are within this kingdom mines of quicksilver, which the crown might at any moment order to be worked, nothing is easier than to demonstrate the expediency of adopting the same plan here, which has succeeded so well in the famons mines of Guancavelica in Peru f- For, first, whenever the supply of quicksilver fails, as has happened times without number, either in consequence of war, of losses at sea, or of the delay attendant upon procuring it from such a distance, the reduction of the ore in the amalgamation works is brought to a stand, the revenue is thrown into arrear, the whole kingdom suffers, the work- ing of the mines is interfered with, and trade receives a check. By setting the quicksilver mines at work, all or most of these evils would be remedied, facilities would be afforded for reducing the silver in an expeditions manner, and the amount of the tenths, the one per cent, and the coinage duty would be augmented.' * Mota, MS. History of New Galicia, c. 62, n. fin. f Solorz. Folit. lib. G; cup. -. 152 Muller on the Structure of the Eyes In confirmation of the above, it may be added, that other veins of quicksilver, appearing, by the analysis of Professor Del llio, to afford ores worth working, have recently been disco- vered in Mexico. Analyses of two specimens of the ore may be seen in the Philosophical Magazine for August, 1828. The pits (shafts) and adits, by the aid of which the water is carried off from the mines, are then described. These, with a chapter describing the operations of the mint of Mexico (vol. ii. p. 233), a vocabulary of mining terms (vol. ii. p. 320), and an enumeration of the mining districts of New Spain (vol. ii. p. 332), are the principal matters falling under the second head, which are treated by the author at length, and with these we shall conclude the present analysis ; passing over the legal department of the subject, which, although forming the bulk of the work, might, we apprehend, be less interesting to the readers of this Journal. Anatomische Untersuchungen uber den Bau der Augen bei den Insekten und Crustaceen vom Dr. J. Muller zu Bonn. Mekel's Archiv fiir Anatomic und Physiologic. 1829. — (Anatomical Investigations of the Structure of the Eyes in Insects and Crustacea, by Dr. J. Muller, &c. &c.) nnHE original observations of Dr. Muller, contained in his -*- * Beitrage zur vergleichenden Physiologic des Gesicht- sinnes, Leipzig, 1826," of which the present paper is a conti- nuation, and which have subsequently been confirmed by G. Treviranus, Huschke, and Straus Durckheim, have hitherto been unnoticed in this country. They are of interest, how- ever, not only as furnishing more correct ideas of the structure and character of the eyes of Insects and Crustacea than those generally received, but also as serving to remove the apparent anomalies by which they were supposed to be separated from the corresponding organs in vertebral animals. It may not be superfluous to state, that, according to the usually admitted opinions, the structure of these organs, whe- ther simple, conglomerate, or compound, is essentially similar; consisting in pyramidal prolongations of the optic nerve, covered by a uniform stratum of black pigment, and externally by a transparent cornea ; the existence of a crystalline or vitreous humour being expressly denied. Such an organization, whilst it presents no analogy with that of the higher animals, places of Insects and Crustaceans Animals. 153 insuperable difficulties in the way of all attempts of explaining the nature of the function, and naturally enough has been quoted in support of the extravagant doctrine which refers the seat of vision in the eyes of animals to the choroid. The observations of Dr. Muller refer to the four different forms of eyes as they occur in Insects and Crustacea, viz. : — 1. Simple Eyes. 2. Aggregates of Simple Eyes. 3. Com- pound Eyes with facets on the external surface. 4. Com- pound Eyes without facets. 1. Simple Eyes. — The eye of Scorpions and Solpugae have all the parts of the eyes of higher animals, viz., a retina sur- rounded by a layer of black pigment, a lens and vitreous humour, and lastly a cornea, convex externally. The black pigment, surrounding the cup-shaped retina, forms at the anterior edge of the vitreous humour a projecting belt, closely embracing the greatest posterior convexity of the lens. In Scolopendra morsitans there are four such simple eyes on each side of the head, of which three are circular, and the fourth and largest, elliptical. In all there is a hard, amber-coloured, and almost circular lens, in immediate contact with the posterior surface of the cornea. Each lens is lodged in a cup- shaped retina, coated externally by black pigment. In these, as in most other simple eyes, there is either not any vitreous humour, or it is so small as to escape notice. In other cases, on the contrary, as Mantis religiosa, Gryllus hierogliphicus, and the larva of Dytiscus marginalis, there is reason to suppose it exists. 2. Aggregates of Simple Eyes. — Of this kind are the eyes of Oniscus, Julus, Lepisma, Cymothoa, &c. In a large species of Cymothoa, where the number of eyes thus aggregated was about forty, Dr. Muller found as many crystalline globes or lenses, one in contact with the posterior surface of each cornea ; they were hard, transparent, and amber-coloured. Behind each lens was a larger globular mass, also transparent and amber-coloured, with a pit on its anterior surface, in which was lodged the posterior convexity of the lens. This larger mass was coated externally and posteriorly by a layer of black pig- ment, and in contact at its back part with a fibre from the common optic nerve, which probably is expanded into a cup- shaped retina, situated between it and the stratum of pigment. 3. Compound Eyes with polygonal facets. — In many Crus- tacea, the existence of crystalline cones or prisms between the facets of the cornea and the fibrils of the optic nerve has long been known. Such were described in Astacus fluviatilis, by 154 Mttller on the Structure of the Eyes Leuwenhoek and Cavolini ; in Pagurus Bernhardus, by Swam- merdam ; in Limulus Polyphemus, by Andre. In Penaeus sulcatus, Dr. Miiller describes the cornea as sub- divided into quadrangular facets, and in contact posteriorly with a stratum of short crystalline masses, the lateral surfaces of which are coated by a greenish opaque pigment, separating them from each other. The crystalline columns, or prisms, are quadrangular, perfectly transparent, very short, being about as long again as they are wide, and in contact posteriorly with the fibrils of the optic nerve. In Lucanus cervus (Coleoptera), the cornea is exceedingly thick, its facets being elongated like prisms. The crystalline bodies are conical, the bases being almost in contact with the cornea, whilst the apices are in contact with the extremities of the fibrils of the optic nerve, each of which is coated externally by a violet pigment. A similar structure with some minor variations is also to be found in Orthoptera, Hemiptera, Lepidoptera, Hymenoptera, Diptera, and Neuroptera. As the general result of such obser- vations, Dr. Miiller describes the structure of such compound eyes as follows : — Behind the facets of the cornea is situated a stratum of elongated transparent prisms, in close apposition to each other, cylindrical or conical, — and allowing the transmis- sion of light in the direction of their longitudinal axis only, their lateral surfaces being coated with pigment. The propor- tion between their longitudinal and transverse diameters varies from 10 : 1, to 2 : 1. The anterior extremity, in contact with the cornea, is sometimes smooth, sometimes rounded. The pigment is sometimes black, as in Dytiscus, Blatta, PhalaenaB, &c. ; at others, as in Penseus, Locusta, Gryllus, &c. yellowish- white, greenish, &c. though still opaque. In some few cases the transparent cones are wanting, though their place is even here supplied by a thin transparent mem- brane, subdivided like the cornea into facets ; e. y. in Vespa crabro, Papilio rhamni, Libellula quadrimaculata, ./Eschna grandis. In Meloe maialis, the cornea is studded posteriorly with transparent projections, very convex, and almost para- bolical. 4. Compound Eyes without facets. — In Monoculus apus the cornea, which is continuous with the common integuments, is smooth, and without facets ; on removing it, the surface of the eye presents a dense aggregate of very small semicircular elevations, which terminate posteriorly in pointed cones, embedded in black pigment, and connected with the tuft- of Insects and Crustaceans 4nimak< 155 shaped extremities of the optic nerve. A similar structure probably exists in all the Monoculi, and most of the inferior Crustacea. In the Daphniae the crystalline bodies are pear- shaped, short, and few in number; such also is the case in Gammarus pulex. In all, the principal peculiarities, inde- pendent of the absence of facets on the cornea, consist in the anterior rounded extremities of the crystalline cones, and the manner in which they project anteriorly beyond the stratum of pigment in which their apices are immersed ; to which, how- ever, there are some approximations in insects. Are these peculiarities connected with the aquatic habits of these animals, rendering necessary a greater refractive power? The pear-shaped masses in the Daphniae and Gammarus pulex present an approach to the lenses of simple eyes, as they occur (aggregated) in Oniscus, &c. The latter, however, besides possessing a spherical lens, have a round vitreous humour, and never the transparent conical masses. The difference from these aggregates is still greater in Monoculus apus, the cones being elongated, small, and numerous. Hence it becomes necessary to discriminate the compound eyes with- out facets, of the inferior Crustacea, as well from the compound eyes with facets of insects and Crustacea, as from the aggregates of simple eyes in Millipedes and Onisci. Ueber den Ban der Augen bei Murex tritonis, Linn., vom Dr. J. Mtiller zu Bonn. (Meckel's Archiv, No. 3, 1829. On the Structure of the Eyes in Murex tritonis.) fTVHE black points at the extremities of one of the pairs of feelers in Helix pomatia, were long ago described by Swam- merdam as eyes, in which he recognised an aqueous humour and a crystalline lens. Subsequently, Stiebel ( ' Meckel's Archiv,' b. 5) examined the same parts in Helix pomatia and Cyclostoma viviparum, and found in them a choroid, an iris, and a crystalline. As the true nature of these supposed eyes of gasteropodous mollusca was, however, still by many considered problematical, Dr. Mulier availed himself of an opportunity of deciding the question by examining them in Murex tritonis. They are here placed at the outer side of the feeler, on a small eminence near its root, the axis of the organ being in the same direction as that of the feeler itself. The surface of the eye is convex, and surrounded by a prominent ridge formed 156 Miiller on the Eye in Murex Tritonis. by the substance of the feeler. The eye itself is easily sepa- rable from the surrounding substance, and is then seen as a blackish sphere, with its greatest diameter in the longitudinal direction. A thin transparent lamella, continuous with the substance of the feeler, is expanded in front of the globe of the eye. This cornea, as it may be considered, is separated from the globe by a space extending over its anterior third, which in the recent state is probably occupied by a fluid (aqueous humour). The posterior part of the globe, embedded in the substance of the feeler, is formed by a greyish-black membrane (choroid), which at its anterior part forms a narrow circular belt of a darker colour (iris), perforated in its centre by a circular pupil. The external margin of the cornea reaches somewhat farther back than the outer edge of the iris. The optic nerve, which is a branch of the nerve running in the axis of the feeler, perforates the posterior part of the cup formed by the choroid, and probably expands on its inner surface into a retina, of which some imperfect traces were visible. The inner surface of the choroid is perfectly black ; its cavity is almost completely occupied by a firm, round, amber-coloured mass, similar to those found in the eyes of spiders, and representing either a crystalline lens or vitreous humour. As the most essential parts of an eye are here present, and of comparatively large size, we are warranted in supposing that there must be a corresponding power of vision. Experi- mental observations on this point are the more desirable, as in Helix and Cyclostoma, where there is a similar organization, the animals appear not to see, or at least not distinguish objects. ( 157 ) FOREIGN AND MISCELLANEOUS INTELLIGENCE. § I.— MECHANICAL SCIENCE. 1. RESISTANCE OPPOSED TO WATER MOVING IN PIPES. — (U Aubuisson.) NOTWITHSTANDING the endeavours made to deduce formulae from ex- periments on the passage of water through tubes, so as to assist and guide the engineer in laying down pipes to supply manufactories or towns, yet frequent mistakes have occurred: thus at Paris, at the Fontaine des Innocens, only two-thirds of the water calculated upon were obtained ; whilst, in the faubourg St. Victor, only the half of that expected issued from the pipes. These differences appear to result from experiments made on too small a scale, or with apertures dis- proportionate to the areas of the tubes ; for the results of practice come sufficiently near to the formulae of MM. Prony and Eytel- wein, when the velocity of motion in a pipe was small in conse- quence of a contracted aperture made in a plate of metal being used. When the contracting plate was altogether removed, then the pro- duct in water was a fourth or third less than that given by the formulae, from which M. D'Aubuisson concludes that the resistance increases with the velocity in a greater ratio than that given to it in the calculations; where it is supposed to increase proportionably as v9 + m v, m being nearly equal to 0.055, and v representing the mean velocity. In consequence of the arrangement and state of the water-pipes at Toulouse, some large and accurate experiments have been made there by MM. Castel and D'Aubuisson, in systems of pipes of 4.7 inches and 10.63 inches in diameter, and 1434 and 1986 feet in length. In these experiments the quantity of water passed and the pressure were varied; the results were noted, and also calculated by the formulae, so as to deduce the loss of pressure due to the resistance of the pipes: that by calculation came out 27., 25., 32.7, and 31.7 per cent, below the result of experiment. As the two latter were the principal experiments, it is concluded that, generally, calculation gives the resistance nearly one-third less than what is obtained by actual and careful practice *. 2. ON THE RESISTANCE OF LEAD TO PRESSURE, AND ON THE INFLUENCE OF A SMALL QUANTITY OF OXIDE UPON ITS HARDNESS. The recent experiments of Mr. Bevan on the compression of lead f, and his proposal of applying balls of that metal to estimate the force of presses, screws, &c., must be well known to English readers. * Annales de Chimie, xliii. p. 224. f Quarterly Journal of Science, N. S., vol. vi.,p. 392. 158 Foreign and Miscellaneous Intelligence. A similar investigation has been entered into by M.Coriolis, which, however, is much more refined as regards those circumstances that enable the lead to resist the force applied. The points at first under investigation by the latter philosopher were temperature, time, impact, and state of the surfaces between which the lead was confined. The pieces of lead were cylinders 24 millimetres in diameter, and 19 in height ; weighing each from 100 to 101 grammes. The arbitrary scale of measurement used gave 680 divisions for the 19 millimetres of height. The lead was pressed between two plates of iron in a kind of box, allowing lateral enlargement as the pressure was exerted, and the measurements of thickness were taken by means rendering the estimation very delicate. To remove any irregularity resulting from differences in the times of pressure, it was in all ordinary cases limited to an exact minute. To ascertain the effect of impact, two pieces, which had been pressed equally, were then re-pressed, the one for two minutes, the other also for two minutes, but at eight different operations. On making thus the effect of impact eight times as much in one case as in the other, still the whole difference was only 19 divisions, which, di- vided amongst the extra 7 impacts, gives only about 3 divisions for each. As to the original temperature, its effect amounts to little or nothing ; for when the cylinders were purposely cooled down, the mere effect of compression evolved so much heat that they could scarcely be touched, and this heat soon overpowered the original difference : experimentally no sensible difference was produced. In reference to the influence exerted by the state of the surfaces be- tween which the lead was pressed, this also proved to be insensible. In the experiments the results are always expressed by the num- ber of divisions to which the thickness of the lead has been reduced from the original standard thickness of 680 parts ; and in this ab- stract we shall only give the mean results. Under the following pressures the ordinary lead used in mints was reduced to the ex- pressed thickness. Kilogrammes . 1500 1824 ]950 3175 Thickness . . 463 336 337 296 When this lead was re-fused and cast, it was found to have increased so much in hardness, as with 1500 kilogrammes to give 490 degrees. Lead was then reduced from the carbonate, and tried after being fused and cast once, twice, thrice, &c., care being taken as much as possible to prevent oxidation by the use of tallow, charcoal, &c,, upon the surface. By the pressure of 1950 kilogrammes it was, after the first fusion, reduced to 333 degrees ; after the second to 351 ; after the third, to 398, always setting off from the standard thickness of 680. This effect was referred to a small quantity of oxide introduced Mechanical Science. 150 into the lead at each time of pouring. To ascertain the truth of this opinion, a stopcock was attached to the bottom of the melting vessel so that the lead could be drawn off without any contact with the atmosphere, the surface above being covered all the time with a thick layer of charcoal powder. Then the former experiments being repeated, it was found that lead, after the first fusion, was reduced to 303, less than on any former occasion ; after a second, to 311 ; and, after a third, to 301 ; so that now no repetition effusion produced any effect. Some of the lead was also cast in this way, being- first raised to a cherry-red heat, and others only to the lowest point necessary for liquefaction. The effects were the same in both : no influence had been exerted over the hardness of the metal, and the changes which usually occur are due to a little oxide introduced. In experiments upon the influence of time it was found that, after a minute had elapsed, the effect of time was masked by the general effect of the metal, and nearly hidden. For a charge of 1950 kilo- grammes the compressions were as follows : — Time . . 30" 45" 60" 75" 90" 120" Thickness 365 331 322 321 319 313 So that here, after a minute, 10" produced an effect of only 2 de- grees upon the scale. Still it was found the effect did proceed ; for with a charge of 1760 kilogrammes the effect was as follows : — Time ... 1 minute 1 hour 24 hours Thickness 317 245 223 So that, after 24 hours, the lead still continued to give way. The most important conclusion from these experiments is, that lead fused and cast in the open air is of variable hardness, and that to obtain it with its true and constant power of resistance, it must be cast out of contact of air, and drawn off from the bottom of the mass *. 3. ON THE POWER OF HORSES. — ( B. Bevan, Esq.) The following experimental data are from a letter written by Mr. Bevan to the Editors of the Philosophical Magazine. " In the period from 1S03 to 1809 I had the opportunity of ascertaining correctly the mean force exerted by good horses in drawing a plough ; having had the superintendence of the experi- ments on that head at the various ploughing matches both at Wo- burn and Ashridge, under the patronage of the Duke of Bedford and the Earl of Bridgewater. I find among my memoranda the result of eight ploughing matches, at which there were seldom fewer than seven teams as competitors for the various prizes, * Annales dc Chiinic, xliv. p, 103, 100 Foreign and Miscellaneous Intelligence. Lbs. The first result is from the mean force of each horse in six teams of two horses each team, upon light sandy soil . =156 The second result is from seven teams of two horses each team, upon loamy ground, near Great Berkhampstead . rr 154 The third result is from six teams of four horses each team, with old Hertfordshire ploughs = 1 27 The fourth result is from seven teams of four horses each team, upon strong stony land (improved ploughs) = 167 The fifth result is from seven teams of four horses each team, upon strong stony land (old Hertfordshire ploughs) . . = 193 The sixth result is from seven teams of two horses each team, upon light loam = 177 The seventh result is from five teams of two horses each, upon light sandy land = 170 The eighth result is from seven teams of two horses each team, upon sandy land = 160 " The mean force exerted by each horse from fifty-two teams, or one hundred and forty-four horses, = 163 pounds each horse; and although the speed was not particularly entered, it could not be less than at the rate of two miles and a half per hour. " As these experiments were fairly made, and by horses of the common breed used by farmers, and upon ploughs from various counties, these numbers may be considered as a pretty accurate measure of the force actually exerted by horses at plough, and which they are able to do without injury for many weeks ; but it should be remembered that if these horses had been put out of their usual walking pace, the result would have been very different. The mean power of the draught-horse, deduced from the above-mentioned ex- periments, exceeds the calculated power from the highest formula of Mr. Leslie;" — which is as follows: (15 — v)* =: pounds avoir- dupois for the power of traction of a strong horse, and (12 — v)2 = pounds traction of the ordinary horse, v — velocity in miles per hour*. 4. ON THE CHANGE OF VOLUME OCCURRING WHEN BODIES COMBINE TOGETHER. An experimental examination of the change of density induced by combination has been undertaken by M. P. Boullay, with a view to ascertain whether any general law could be deduced by which might be obtained an insight into the density of substances generally when in combination. His first care was to obtain the specific gravities of many bodies, simple and compound, to a high degree of accuracy, and in this respect every precaution appears to have been taken. Then comes the point principally under discussion: either the spe- * Phil. Mag., N. S., viii. p. 22. Mechanical Science. 161 cific gravity of a compound is the sum of the specific gravities of its elements, or it is different in consequence of contraction or dilata- tion. In by far the greater number of cases it proves to be different : thus, in the sulphurets of mercury, lead, arsenic, antimony, tin, and iron, the specific gravity is increased; in the iodide of potassium it is also increased ; in those of silver, mercury, and lead, it is dimi- nished. Then endeavouring to determine whether the contraction was the same for bodies having similar atomic composition, no analogy was found ; so that, though many sulphurets and iodides have been examined carefully, nothing can be deduced from them relative to other sulphurets and iodides : even constancy of contrac- tion or expansion cannot be deduced, for the iodides present cases of both. These results on the sulphurets and iodides appear to M. Boullay important, not only as adding facts to our knowledge, but as marking and destroying an error into which many philosophers, occupied with the same question, have fallen. They have endeavoured to deter- mine the specific gravity of bodies brought to the same condition, (the solid state, for instance,) but have been stopped by those sub- stances which cannot be brought into that form. Assuming the hypothesis, however, that in the union of two bodies in the solid state there was neither expansion nor contraction, or else that the negative element only was altered, they have thought themselves justified in deducing from the specific gravity of a binary compound and one of its elements, the specific gravity of the other : thus the densities of oxygen and chlorine have been calculated from the metallic oxides and chlorides. This assumption is entirely done away by the facts quoted. Even admitting for a moment the hypothesis as good, calculation from it proves its own fallacy : thus the density of oxygen derived in this way from the oxides varies from 1.25 to 5.88, which, without experiment, would prove great modifications by expansion and con- traction. The chlorides gave still more striking results for chlorine ; and from the specific gravity of the chloride of potassium it would appear that a volume of this binary compound contains more than its volume of metal only, indicating an enormous contraction between that substance arid the chlorine*. 5. APPARENT HYDROSTATIC ANOMALY WITH LAUREL-OIL. Dr. Hancock has remarked a curious apparent anomaly in the hydrostatic pressure of two fluids, the lighter of which, upon mix- ture, passed to the bottom, and the heavier to the top. One of the fluids is laurel-oil ; the other a mixture of pure ether (i. e. free from alcohol) and proof spirit in equal proportions, or with a slight excess of ether. Such a mixture is lighter than the essential oil, but when the latter is poured upon the former it floats, and indeed whichever * Annales de Chimie, xliii. 266. VOL. I. OCT. 1830. M 162 Foreign and Miscellaneous Intelligence. is added last the same effect takes place ; nor does the ultimate state of things differ, whether the mixture be made gently, or violent agitation be given to it. Dr. Hancock concludes that these seemingly strange appearances result from the strong affinity of the essential oil for ether, by which it attracts it from the mixture with alcohol, combines with it, and so forms a mixture essentially lighter than the ether and spirit. He found, by trial, that though the essential oil would not mix with ether if at all adulterated, that with pure ether it dissolves in ever^ proportion. A remarkable circulating motion was also observed when laurel-oil and alcohol were brought together. * Take a phial of the laurel-oil, and drop into it at different intervals some rectified spirits of wine, when the most interesting results will be observed to ensue — a circulation, presently commencing, of globules of alcohol up and down through the oil, which will last for many hours or for days, (how long is unknown.) A revolving or circu- lating motion also appears in the oil, carrying the alcoholic globules through a series of mutual attractions and repulsions ; the round bodies moving freely through the fluid, turning short in a small eccentric curve at each extremity of their course, passing each other rapidly without touching, but after a time they seem to acquire a density approximating to that of the lower stratum, which appears to be an aqueous portion separated by the ethereal oil from the alcohol ; and this assimilation taking place, the globules, after per forming many revolutions, will fall flat upon the surface and unite with the lower or watery stratum. This experiment was performed with a small phial : perhaps a larger one would render the result more perspicuous*.' 6. ON THE QUANTITY OF LIGHT REFLECTED BY METALLIC SPECULA AT DIFFERENT ANGLES OF INCIDENCE. — (R. Potter, Esq.) A paper upon this subject has been read to the Royal Society by Mr. Potter, in which he shews some curious departures in fact from generally received opinions. Sir Isaac Newton has stated, that metallic specula, in common with all other substances, reflect light most copiously when incident most obliquely. Some experiments made by the author, with specula of his own construction, having raised doubts in his mind as to the accuracy of the prevailing opinion on this subject, which accords with that of Newton and of Bouguer, he instituted a more exact inquiry into the proportions of incident and reflected light from specula at various angles of incidence. He used for this purpose a photometer resembling that of Bouguer, and consisting of an upright screen with a square aperture, across which a piece of thin tissue paper was extended, destined to receive on one compartment the reflected light from one lamp, and on another * Brewster's Journal, 1830, 48, 51. Mechanical Science. 163 compartment the direct light from another lamp, employed as a standard of comparison. By adjusting the respective distances of the lamps, the lights on the paper were rendered sensibly equal in point of intensity, the equality being judged of by the eye viewing them from the other side. The measurements were taken alternately, first one of the direct, and then one of the reflected lights, until a sufficient number of uniform results were obtained. The author, after taking every precaution that occurred for insuring accuracy, invariably found that the proportion of light reflected from metallic substances, instead of increasing, diminished in pretty regular gra- dation, as the angle of incidence was augmented. Thus, in the first experiment, when the angle of incidence was 20°, the proportion of the reflected to the incident light was as 69.45 to 100 ; at 40° it was 66.79 ; and at 60° it was reduced to 64.91. Some irregula- rities occurred in the series of results deduced from different sets of experiments, arising partly from the variableness of the light given out by the lamps, and partly from the difficulty of preserving the metallic surface in the highest state of lustre which it has when newly polished. The author combats the opinion, that the quan- tities of light which metals are capable of reflecting when polished, are in the ratio of their densities ; and finds that in those metals which were the subjects of his experiments, the quantities of light absorbed or lost by reflection at incidences nearly perpendicular are almost exactly in the ratio of their specific heats*. 7. ON THE APPARENT PROJECTION OP STARS UPON THE MOON'S DISK. The attention of astronomers has lately been called in a particular manner, by Sir James South, to the extraordinary effect which had often previously been observed of the apparent projection of the stars upon the moon at the time of occultation. The star, on coming up to the moon, in place of disappearing instantly behind its edge, appears (for several seconds occasionally) to advance a short space on to or before its disk, and then disappear. This effect does not always happen with the same occultation ; some persons see it- others do not; it happens for variable periods of time, and upon both the dark and bright limb of the moon, though most frequently upon the latter^ A very curious letter upon this subject has been written by M. Gergonne to the editor of the Bibliotheque U?u'versellet in which he describes an example of this illusion, of rather an early date. * Before 1789, or rather in 1786, I cannot say at what season, as I was coming after mid-day from the College of Nancy, where I studied, (it consequently was about a quarter to five o'clock,) I found about a dozen men and women in a group, at the bottom of the Rue St. Michel, very nearly in front of an Eglise de Penitens * Phil. Mag., N, S., viii, 60. 164 Foreign and Miscellaneous Intelligence. which has disappeared in the revolution — their eyes being atten- tively fixed on the sky. Inquiring1 of one of them what was the matter, he pointed with his finger to the object of their attention, at the same time saying, " A star on the moon !" and, in fact, I saw a star of considerable brilliancy on the edge of the enlightened part of the moon's disk. According to the position of the star relative to the sun, which was still far from setting, this should have hap- pened in the spring or autumn, near the first quarter. I remained some instants considering the phenomenon, which gradually dis- appeared. I cannot now say positively whether the star disappeared behind the moon, or whether it separated from it. * Although I was not at that time much versed in astronomy, I did not doubt that the supposed star was Venus, which I had some- times observed in full daylight ; and as I also knew that Venus was placed in the heavens as to us far beyond the moon, the phenomenon appeared very surprising to me ; and hence, doubtless, the reason why I have preserved the recollection of it. * This particular fact would have nothing more remarkable than many others which had been cited, if it did not establish, i. That the phenomenon may be seen in full day-light; ii. That it may be well observed with the naked eye, and that, consequently, the ex- plication is not to be found in any action of the telescopes ; iii. That it does not depend upon such a condition of the eye as, being purely accidental or exclusively proper to such and such persons, would prevent its uniformly affecting several persons collected together accidentally ; iv. That its duration may much exceed that of some seconds, for on this occasion it certainly lasted above a minute. Such a prolonged effect should necessarily happen each time that the motion of the occulted star is, with respect to the moon, nearly a tangent to its disk ; and if I had at hand the volumes of the Connaissance des Terns for that time, I should, without doubt, find that the occultation which I have described, and which I should then be able to refer precisely to the year and day, would be in this condition. It is also to occultation of this kind that the preference should be given, that leisure may be obtained for the correct ob- servation of the appearances.' This letter is signed J. D. Gergonne, editor of the Annales des Mathematiques, and in a note to it, it is stated that in the Connaissance des Terns for 1788, p. 43, may be found mention of an occultation of Venus on the 9th April, 1788, about three hours fifty-four minutes afternoon, which might be seen from many parts of the earth, but not at Paris*. 8. ON THE PRODUCTION OF COLOURED BANDS BY PLANE MIRRORS. If a person stand before a silvered mirror and observe the re- flected image of a candle, he will see at its sides several verv * Bib. Univ., 1830, 345. Mechanical Science. 165 apparent coloured bands. The light may be held a few inches before the eye, and so that the incident and reflected rays may make but a small angle. This experiment is due to Mr. Whewell of Cambridge ; but M. Quetelet, on repeating it, found that it was not constantly produced, and that the necessary condition was the presence of a slight film of vapour on the glass*. To make the experiment it is sufficient to breathe upon a cold mirror at the place where the image of the candle is to be reflected. M. Quetelet has found that the experiment succeeds as well when the mirror is not silvered ; even a piece of crown glass will do ; but, from its irregularities, the bands are not so distinct. Day- light does not interfere with the observation. A drop of oil behind the glass makes the colours disappear. A line from the image of the eye to the image of the light is always perpendicular to the direction of these coloured lines. The bands affect the form of curved lines, which, in certain cases, degenerate into straight linesf. They do not extend far beyond the image of the light. The colours proceeding from the light are bluish-green, yellow, red ; bluish- green, yellow, red, &c. Other circumstances being the same, the bands are larger as the observer is farther from the mirror, as the ligfit is nearer to the eye, and in fact as the angle between the inci- dent and the reflected rays is smaller. This phenomenon does not appear to be related to that which Newton observed with concave mirrors. It appears, as to the colours, to have more connexion with the effect observed when the sun or a light is seen through a transparent plate upon which has been spread a very fine powder. The breath forms but a transient haze ; but M. Quetelet has found an easy mode of rendering the preparatory state of the glass permanent. It consists in extending a very thin regular film of fatty matter, as oil or tallow, over the glass ; a soft cloth is to be pressed lightly or dabbed over the whole surface of the film to destroy the parallel lines otherwise existing, and then the effect is obtained as well as with the breathj. 9. SIZE FOR ILLUMINATORS, ARTISTS, &c. .Four ounces of Flanders glue and four ounces of white soap are to be dissolved on the fire in a pint of water, two ounces of powdered alum added, the whole stirred and left to cool. It is to be spread cold with a sponge or pencil on the paper to be prepared, and is much used by those who have to colour unsized paper, as artists, topographers, &c.§ * Many mirrors produce the effect without the film, in consequence of a slight granulation left upon the surface of the glass by the manufacturer. — Ed. f We have never seen the bands in a flat piece of glass otherwise but straight. — -Ed, I Bull. Univ., A. xiii., 190, 192. § Ibid. E. xiv. 344. 166 Foreign and Miscellaneous Intelligence. § II.— CHEMICAL SCIENCE. 1. GALVANIC CURRENTS DURING THE DECOMPOSITION OF WATER. The following description is from the personal observation of Pro- fessor Silliman. * In the decomposition of water by the galvanic power, two tubes being filled with water, and inverted in a vessel filled with that fluid, their orifices being about one inch apart and the connexion established through the fluid by slips of platina, I had recently the satisfaction of observing distinctly the currents of gas as they took their departure to their respective poles. It has been a problem, whether the water is decomposed under one tube, or the other tube, or at some intermediate point; but, in the expe- riment referred to, ocular demonstration was exhibited, that the decomposition took place simultaneously, under both tubes, and not at any intermediate point. This appeared from the fact, that under each tube a current of gas rose vertically from the platina slip, and collected in the top of the tube, while another current shot off laterally and took up its march towards the opposite pole beneath the contiguous tube : as this process was going on at the same time under both tubes, it follows that there were opposite currents of gas, but they occasioned less mutual disturbance than might have been supposed ; because the levity of the hydrogen and the gravity of the oxygen determined them to pass each other at dif- ferent levels, and although many bubbles were buoyed up in the passage, and made their escape, and were lost by passing through the water intermediate between the two tubes, a large part of the gases was collected in the respective tubes. The process was con- tinued for several hours with a large battery, and the currents were palpable to all the bystanders. With a magriifying-glass the ap- pearance was beautiful, and nothing can exhibit more decisively the all-dominant power of the galvanic influence in causing even gaseous elements to separate at different points, and to pass horizontally, in opposition, through at least two inches of water, until they arrived at the poles by which they were respectively attracted : but, on examining the gases in the two tubes, so far from finding the oxygen gas in the one and the hydrogen in the other, there was found in both a highly explosive mixture, which gave a very sharp report when a flame was applied ; and in fact the result was pre- cisely the same as when the two tubes, standing in different vessels and furnished with metallic caps and depending platina wires, to connect them with the slips of the same metal below, are joined by a good conductor touching the caps. Did the strong mechanical conflict of the two opposite currents cause the gases to be intermingled and thus to be in part carried into the stream? or did a portion of each gas fail to be expelled from the tube by the attractions and repulsions, and thus rise by mere Chemical Science, 167 levity, to mingle with the gas appropriate to each particular pole * ? We can by no means consider Professor Silliman's account as at all altering the state of our knowledge relative to where the decompo- sition of water occurs, between or at the voltaic poles. The Pro- fessor seems to imply that it takes place at both poles, quoting the two currents from each pole as the proof; but there is no proof that the two currents were not of the same gas, i.e., both oxygen at the positive and both hydrogen at the negative pole ; and, in fact, that is the only way of accounting for the mixture of both gases in both receiving tubes. There is great reason to believe that the arrangement of the gas at each pole into two currents, one internal and the other external to the receiving tube, was a mere conse- quence of the descending water carrying off the smaller bubbles with it.— Ed. 2. POWER OF METALLIC RODS, OR WIRES, TO DECOMPOSE WATER, AFTER THEIR CONNEXION WITH THE GALVANIC PILE is BROKEN. — (Berzelius.) In the experiments which I undertook in 1806, 7, in company with Mr. Hisinger, we had found that rods of metal which were em- ployed to decompose water by means of the galvanic pile, continued to develope gas after their connexion with the pile had ceased, a circumstance which seemed to indicate a continuance of electrical state, though these rods shewed no action upon any other portion of liquid, even of the same kind, than that in which they had been placed during their contact with the pile. This observation, which I had almost forgotten, has been lately confirmed by Pfaff, who has also added to it several others of a similar kind. We might suppose such effects to be produced by a residual polarity, both in the liquid and the metal, shewing itself, as long as it continues, by a continua- tion of chemical action ; but some of Pfaff 's experiments seem to oppose this idea, for he found that the addition of ammonia to the liquid, by which all its internal polarity was destroyed, did not deprive the wires of their effect. The metals which acquire this property in the highest degree are iron and zinc, next to which is gold. He attempts to explain the phenomenon, by supposing that the continued passage of the electrical stream had brought the elements of the water nearer to a state of separation, so that a very slight influence was sufficient to destroy their union. It must be confessed, however, that we cannot at present advance a satisfactory explanation!. 3. ON PYROPHOSPHORIC ACID AND THE PYROPHOSPHATES. Mr. Clarke first pointed out the singular change induced upon the phosphates by calcination, and, conceiving the acid was changed in its nature, gave it in its new condition the name of Pyrophos- * Silliman's Journ., xviii. 199. f Berzelius, Arsberattelse, 1829, p. 33. 168 Foreign and Miscellaneous Intelligence. phoric acid. Gay-Lussac then gave further light on the subject, and now M. Stromeyer has published an investigation of the sub- ject, which adds Very much to what was before known. M. Stromeyer first compares the two salts of silver, namely, the phosphate and pyrosphosphate, as those compounds which most strikingly exhibit the new characters impressed on the acid. Both these salts are pulverulent, and, when well dried, anhydrous ; the first is yellow, the second white ; the first has a specific gravity of 7.321, the second of 5.306. The first fuses with great difficulty, requiring a very high temperature, and cools into a yellow mass. The second fuses beneath a red heat into a brown liquid, which, by cooling, becomes a colourless, crystalline mass. Both salts are insoluble in water, both dissolve in nitric and sulphuric acid, and are precipitated unchanged ; but when the pyrophosphate is heated in solution, it becomes ordinary phosphate. Muriatic acid decom- poses it, but without changing the peculiar character of the acid. All the metallic pyrophosphates, boiled with phosphate of soda, become phosphates, and form pyrophosphates of soda — the reverse does not take place. Hence pyrophosphoric acid should be placed after phosphoric acid in chemical affinity ; and this alone establishes an important distinction between the two. Most of the pyrophosphates recently precipitated dissolve freely in the solution of pyrophosphate of soda. The same effect does not happen with the phosphates and phosphate of soda. Hence, that a great difference exists between the phosphoric and the pyrophosphoric acid is evident, although the latter is obtained by calcining the former, or by burning phosphorus in oxygen ; still there are plenty of reasons why the difference should not be due to either an excess or deficiency of oxygenation in this respect. M. Stromeyer shews that both are alike ; neither does it depend upon more or less water combined, for the two salts of silver are both anhydrous, and yet their properties are distinct. M. Stromeyer determined the composition of these two salts, and, by various modes of experimenting, proved that they contained different proportions of acid and base. The result of all his experi- ments was, that the proportions per cent, were as follows : — Oxide of Silver. Acid. In the phosphate . . 83.454 . 16.545 pyrophosphate . 75.390 . 24.610 for equal quantities of acid, therefore, the quantity of oxide of silver in the two salts is as 3 : 5. This great difference in saturating power is the cause why, when a neutral phosphate of soda is calcined, it becomes strongly alkaline, for the phosphoric acid present, by be- coming pyrophosphoric acid, loses two-fifths of its neutralising power, and yet this extraordinary effect happens without any loss of acid, or any change in the quantity of its constituents. The whole dif- ference depends upon the manner in which the elements combine, and it is one more added to the very few decisive cases previously known, in which the mere mode of combination, and that too in a Chemical Science. 169 binary compound, produces such differences of properties as to con- stitute the products real and distinct substances*. 4. PRODUCTION OP HYDROCYANIC (PRUSSIC) ACID UNDER UNCOMMON CIRCUMSTANCES. — (A. A. Hayes.) Wishing to decompose some nitric acid containing about one-third its weight of dry acid, it was subjected to distillation with one-third of its weight of raw sugar; the distillation was attended by the production of vapours of nitrous and hyponitrous acids, as is usual in the decomposition of nitric acid. The fluid in the receiver was slightly acid, it was therefore returned to the retort still containing the residue of the first operation, and gentle heat applied ; the strong and peculiar odour of hydrocyanic acid was developed, in such a quantity as to render the atmosphere of a small room irre- spirable. After cooling the apparatus and decanting the distilled fluid, a few drops of ammonia were added, and the alkaline fluid, mixed with a solution of proto-sulphate of iron, and a few drops of acid, deposited a bulky precipitate, which, on exposure, became of a fine blue colour. — Rosebury Laboratory, March, 16th, 1830 f. 5. ACTION OF CHLORINE ON CARBURETTED HYDROGEN. — A memoir upon the action of chlorine on carburetted hydrogen, consisting of single proportionals of carbon and hydrogen, has been read by M. Morin to the Societe de Physique, &c., of Geneva, of which the following is a brief abstract. The investigation was rendered necessary in consequence of the conflicting statements put forth by different philosophers of the nature, composition, and pro- duction of the resulting substance. When chlorine and olefiant gas are brought together over water, a compound sometimes called chloric ether, or hydrocarburet of chlorine, is formed, which was analysed several years since by MM. Robiquet and Colin: they concluded, from all their experiments, that it consisted of equal volumes of chlorine and olefiant gas com- bined together, and in fact, it was well ascertained, that in these proportions the substance was abundantly produced, and the gases disappeared. M. Morin analysed it by passing its vapour through a tube heated to dull redness : carbon was left in the tube and a gaseous mixture obtained, containing two volumes of muriatic acid gas, and one volume of a peculiar carburetted hydrogen, containing twice its volume of hydrogen, in combination with 0.6 of a volume (as the hypothesists say) of the vapour of carbon ; 3.7 parts of the hydro- carburet of chlorine were used, and, according to the received opi- nion of composition, a fourth more of muriatic acid, and a third less of the carburetted hydrogen gases ought to have been obtained. Hence it appeared, that a very considerable part of the chlorine * Ann. de Chim., xliii. 364. f Silliman's Journal, xviii. 201 . 170 Foreign and Miscellaneous Intelligence. had somehow disappeared. M. Morin found this in the water over which the compound had originally been formed ; for although both gases may have been well purified, this water always becomes strongly acid, and in fact, being saturated with bi-carbonate of potassa, eva- porated to dryness and ignited, the chloride of potassium produced was found to contain half the chlorine which had been employed in forming the oily fluid. Hence the true theory of action is as follows : four atoms of car- buretted hydrogen being acted upon by two atoms of chlorine (equal volumes), one of the former gave its hydrogen to one of the latter, to form one of muriatic acid, and its carbon to the other atom of chlorine, to form an atom of proto-chloride of carbon. This atom of proto-chloride, combined with the remaining three of carburetted hydrogen, forms the chloric ether * ; and upon consi- deration it will be found, that such a compound would give by decomposition the proportion and kind of gases before stated to occur. Action of Chlorine on Alcohol. — As alcohol and ether may be considered as hydrates of carburetted hydrogen, M. Morin then closely investigated the effect of chlorine upon them. In the alcohol experiment, the chlorine being disengaged in a matrass, then passed through a vessel containing chloride of lime, next through that containing the alcohol, next to this was a vessel containing water, and ultimately a fourth with a solution of chlo- ride of lime ; the third vessel was to absorb any muriatic acid formed, and the fourth to saturate any carbonic acid which might be disengaged. When the chlorine was passed very slowly, and the alcohol was very pure, the whole of the gas was absorbed, and a greenish oily liquid was deposited at the bottom of the vessel. Gradually the absorption of chlorine diminished, but did not cease until several days had passed, after which the bubbles were increased in bulk whilst traversing the liquid. There were then two liquids in the vessel, the lower third was oily, whilst the upper part was very acid and fuming. Either could be coloured green by a slight excess of chlorine. The increase in weight indicated the chlorine absorbed, and by saturating the acid liquor with bi-carbonate of potassa, the quantity of muriatic acid produced was easily deter- mined. Of the two liquids, the lightest was found to precipitate by water, and to be a solution of the heavier in acid ; the quantity thus dissolved was estimated by comparative experiments. The quantity of carbonic acid produced was as nothing, the trace existing probably came from the manganese. The experiment proved that chlorine combined with alcohol in a volume equal to that of the hydro-carbon present, estimated in the same state ; that half the * We have ventured to alter the number of atoms, &c., referred to by M. Morin in illustration, without, however, altering the sense of the statement. M. Morin doubles the atom of carbon, and calls it vapour, &c. ; the consequence is, that in the very passage altered, the theoretical impropriety occurs of saying, that fo'-car- burettcd hydrogen is composed of two atoms of hydrogen and one of carbon. — Ed. Chemical Science. 171 chlorine became muriatic acid, and that the other half formed a substance of the same specific gravity as the hydro-chloride of carbon. Hence, it may be concluded that chlorine acts on alcohol as it does on olefiant gas ; that the composition of the substances obtained in both cases is the same, and that the water of the alcohol is not concerned in the action. A good result can only be obtained in operating at temperatures close to 32°, in allowing only a very slow current of chlorine, and in effecting complete saturation. The operation will soon appear terminated, but in such cases a very variable oily product will be obtained. Action of Chlorine on Ether. — The same kind of experiment, and with the same apparatus, was then made with ether, also a hydrated hydro-carbon. By keeping the temperature at 32°, or below; moderating the current of chlorine; and continuing the operation until the saturation was perfect ; all the muriatic acid produced passed into the third vessel, or that containing the water. In place of the ether, nothing remained but a green liquid impregnated with chlorine, and of the specific gravity of chloric ether. The muriatic acid produced represented half the chlorine : the oily matter was equal to what the hydro-carbon in the ether could have produced, as olefiant gas with chlorine. The quantity of carbonic acid evolved was quite insignificant; the water of the ether was inert during the action, and in fact, the action of chlorine is the same whether olefiant gas, alcohol, or ether be used. Although all proceeds successfully if every precaution be taken, yet inattention easily gives erroneous results, If the saturation be incomplete, the oily matter varies in density and quantity. If the current of chlorine be rapid, ether is carried off into the water and escapes the action. If the temperature rise, the muriatic acid and ether react upon each other, and muriatic ether is produced. The substances thus produced, though alike in composition, vary in some properties, and principally in taste and odour; these differ- ences, it is supposed, may be due to a little sweet oil of wine. That made with the gases has a sweet penetrating taste and agreeable odour ; those with alcohol and ether have an acrid taste, resembling more that of peppermint ; in colour and some other qualities they differ slightly. They agree, however, in specific gravity, which is between 1.22, and 1.24 ; in extreme solubility in alcohol and ether; in being almost insoluble directly in water, but soluble by means of muriatic acid, and remaining in solution after the acid is neutralised. All produce by combustion a green flame, and abundant vapours of muriatic acid*. 6. BROMIDE OF CARBON. The following account of this substance is extracted from a work on bromine and its chemical combination, by C. Lcewig. * Ann, do Chimie, xliii. 225. 172 Foreign and Miscellaneous Intelligence. Bromide of carbon may be prepared in two ways ; according to the first method, bromine is mixed with alcohol at 36° Baumti. The mixture heats strongly, and if bromine is still added, a moment of sudden effervescence supervenes, accompanied with disengagement of vapours of hydro-bromic acid and free bromine. After the liquid has cooled, there is added an alcoholic solution of caustic potash until discolouration is produced ; water is then poured in, and the alcohol is evaporated at a gentle heat. When the liquid begins to cool, there separates a small quantity of a yellow oil, heavier than water, and immediately after a concrete crystalline matter. The alcoholic solution may also be diluted with a large quantity of water, and in this manner the concrete substance equally separates with the oil. This combination, however, may be obtained in greater quantity by the following process. Bromine is put along with ether for a certain time, and the mixture is then distilled. At first there only passes hydrobromic acid, and then comes a very clear oil, which falls to the bottom of the liquid that has already passed. When the distillation has been continued for some time it is interrupted, pure potash is added to the residuum, and it is diluted with water. There is then deposited a voluminous white mass which is washed with water upon a filter. It is then melted at a very gentle heat, and allowed to harden by cooling. This bromide of carbon forms white opaque scales, greasy to the touch, like camphor, and friable. Its smell is highly aromatic, re- sembling that of nitric ether ; its taste is sharp, like that of pepper- mint. In the fluid state it is transparent and colourless. It burns as long as it is in contact with flame, and disengages vapours of hydro-bromic acid. It is heavier than water, melts at a slight degree of heat, evaporates at 212° F., and sublimes, forming aci- cular crystals, having a pearly lustre. It is but feebly dissolved by water, to which it communicates its smell and taste. When the water is at 122° F., it is dissolved, and at a higher degree it is in part evaporated with the vapour. Alcohol and ether easily dissolve it, and the solutions are not rendered turbid by nitrate of silver. Alkalies have no action upon it, even at the boiling temperature. Sul- phuric, hydrochloric, and nitric acids have no. effect upon it. When the melted bromide of carbon is submitted to a current of free gas, chloride of brome is immediately formed. On heating it with the oxides of iron, copper, zinc, &c., there are obtained metallic bro- mides, and carbonic acid gas. By making it pass these metals in the state of vapour, there are obtained metallic bromides and charcoal. It is to this latter property that M. Lee wig has had recourse for analysing the bromide of carbon, which is composed of 9.01 carbon, and 91.99 brome, the atomic weight of the latter being F= 941.1*. * Eclin. Nat. Journal, ii. 233. Chemical Science. 173 7. PREPARATION OF PHOSPHURET OP LIME. — (Dr. Coxe.) 1 employ two Hessian crucibles, some of the inner members of a nest. The larger of the two has a hole bored through its bottom, and a test tube of a suitable size luted in with clay. The phosphorus is put into the test tube, the top of which is loosely covered with a piece of broken crucible to prevent the small pieces of quicklime from running down into it. The lime is then put in so as to fill this crucible and partly fill the upper smaller one, which serves as a cover to it, and is luted on with some fine clay a little moistened. The cover has also a small hole in its top to afford an outlet for the air, or volatilised phosphorus, if there should be any occasion for it. The whole is now placed upon the grate of a furnace, with the test tube projecting through and appearing below, and a charcoal fire kindled around it. The phosphorus may be kept cool if it should be ' thought necessary, by making the tube dip into the water, contained in a tin cup attached to the end of a stick. When the crucibles and their contents are thoroughly red hot, a chafing dish is substituted for the tin cup, and the phos- phorus rising in vapour produces the desired change. The phos- phuret should be preserved in a sealed vial. The same crucibles may be used a number of times*. 8. IODIDE OF POTASSIUM A GOOD TEST FOR ARSENIC — CURIOUS COMPOUND PRODUCED. Professor Emmett of Virginia has recommended the iodide of potas- sium, or iodine alone occasionally, as a useful test for white arsenic. He found that when the iodide was added to a solution containing only 2.8 per cent, of arsenious acid, or 1.8 per cent, of arsenite of potassa, or when iodine alone was added to a solution containing 2.8 per cent, of arsenite of potassa, an immediate precipitation took place. If the precipitation be performed with drops upon a glass plate, then -jj^dth of a grain of arsenic is sufficient for the pur- pose; the precipitate, when gradually formed, is white, adheres with great tenacity to the glass plate, and then may be thoroughly washed, and will present the following characters. Concentrated nitric acid changes the white colour to a dark brown, purple, or even black, from free iodine ; and starch added at the same time, becomes deep blue. Strong hot sulphuric acid does the same ; when cold, it merely produces a bright yellow, the latter effect is produced by strong muriatic acid. Metallic salts are not likely to cause errors in the use of this test, because, if originally present, they are sepa- rated by the carbonated alkali used to dissolve the arsenious acid. The presence of coffee, tea, milk, and other liquids, does not seem materially to retard the precipitation. The substance thus formed appears to be a curious compound. It resembles arsenious acid in solubility and precipitation ; thus, * Sillimaa's Journal; xvii. 349. 174 Foreign and Miscellaneous Intelligence. hot water dissolves about 5.3 per cent and deposits nearly one half on cooling-. It requires a much higher heat than white arsenic for its volatilisation (550° Fahrenheit), and at 600° is decomposed, giving off first arsenical fumes arid then evolving iodine. On ana- lysing the substance it turned out to be a compound of Arsenious acid . . 63 . 3 Iodide of potassium . 36.7 100.0 Notwithstanding the novelty of such a compound, in which it is impossible to tell whether the white arsenic acts the part of acid or base, although it is present nearly to the extent of five atoms, and where no analogy to the composition of a double salt appears obvious ; yet Professor Emmett observes there are facts from which its exist- ence must be inferred. Thus iodide of potassium, even when added in great excess, does not precipitate the whole of the arsenite of potassa, nor is it capable of diminishing the alkaline reaction ; on the contrary, when arsenite of potassa is so far neutralized by free acetic or arsenious acid as not to affect turmeric paper, it acquires this property by the addition of iodide of potassium, apparently in consequence of a union between the latter substance and the excess of arsenious acid, which while dissolved had the power of counteract- ing the alkaline effect : other considerations lead to the same result. If subsequent experiments should establish the existence of such a compound, it will be a solitary but striking example of what may be considered a chemical hybrid *. 9. AMMONIA IN NATIVE OXIDE OF IRON. — (Boussingault.) Vauquelin shewed that rust of iron contained ammonia, and Che- vallier shewed that the natural oxide of iron also contained the same alkali. As the oxides the latter worked with came from a dis- tance, it might be urged that they had acquired ammonia by the way ; for if rust formed within houses absorbed ammonia, so also might native oxides acquire that alkali in its transit from place to place. M. Boussingault, therefore, sought to ascertain whether the natural oxides of iron gave the substance immediately after their extraction from the earth. In the mine of Cumba near Marmato, a large vein of hydrated oxide of iron in syenitic porphyry is worked as a gold ore. In a part of this mine, called por a fuera, where the work proceeds with activity, about a foot of mineral was broken down at the end of the excavation so as to expose a fresh surface, and then a hole was bored in the very middle of the vein ; after having been carried eight inches deep, the powder of the ore was collected carefully in a basin, placed under the hole, and touched by nothing but the tool. Four ounces of this ore were then bruised and rubbed in distilled * Sillimau's Journal, xviii., 58, Chemical Science. 175 water, the filtered liquid was acidified by muriatic acid and evapo- rated ; it left fifteen grains of residue, which being introduced into a glass tube with a piece of quicklime slightly moistened and heated, gave ammonia sensible not only to test papers, but also by its strong odour. Hence it results, as M. Chevallier has stated, that the natural oxides of iron contain ammonia, and this fact, conjoined with that of Austin, that ammonia is formed by the oxidation of iron in contact with air and water, acquires a certain degree of geolo- gical importance*. 10. ATOMIC WEIGHT OF TITANIUM. — (Rose.) M. Rose some time since endeavoured to ascertain the atomic weight of titanium from the analysis of its sulphuret, but finds, as he suspected, that the sulphuret often contains titanic acid, and there- fore yields uncertain results. In fact, when chlorine was passed over the heated sulphuret, besides the chlorides of titanium and sulphur, titanic acid always appeared. He has, therefore, resorted to the chloride of titanium as a more definite compound ; a mixture of titanic acid and charcoal is heated and chlorine passed over it ; the chloride of titanium formed is recti- fied from off mercury or potassium t several times to remove the excess of chlorine, and is then a clear limpid fluid like water, leaving no trace of chlorine when decomposed by water. If this chloride and water be brought together suddenly, heat is evolved, and the solution is milky ; if the chloride is left in a moist atmos- phere, the action takes place without the least formation of turbid- ness. After some time the titanic acid is precipitated by ammonia, carefully added so as not to be in great excess, exposed to a mode- rate temperature to dissipate the excess, and filtered to separate the titanic acid. The above liquor is then mixed with nitric acid, and the chlorine precipitated from it by a solution of nitrate of silver. The titanic acid and chloride of silver are then weighed and give data to determine the quantity of titanium and chlorine in the original compound. From the mean of many experiments thus made, it would appear that one hundred parts of the compound contain Chlorine . 74.46 . . 71.461 Titanium . 25.54 . . 23.539 and as 74.46 chlorine correspond to 16.82 oxygen, that the titanic acid is composed per cent, of Oxygen . 39.71 . I . 36.130 Titanium . 60.29 . | . 63.870 Dumas, some time since, endeavoured to ascertain the specific gravity of the vapours of the chloride of titanium, and found it to be 6.836, that of air being 1. This would give the composition of the above compounds as expressed in the second column of figures. The cause of this difference between the results obtained is, at * Ann. de Chimie, xliii., 334. | Potassium does not act upon the compound at boiling temperatures. 176 Foreign and Miscellaneous Intelligence. present, unknown, but unfortunately throws doubt upon both processes*. 11. ON THE CRYSTALLIZATION OF GOLD. — (Professor Henslow, of Cambridge.) A small glass-stoppered phial, containing a solution of gold in a mix- ture of nitric and muriatic acids, had stood long neglected for a considerable time (perhaps four or five years) in a cupboard. Upon accidentally discovering it, I found a portion of the acid had escaped and the gold crystallized. This effect had probably been promoted by a flaw in the phial, which extended through the neck, and a little way down its length. The stopper, in consequence, must have been slightly loosened, and thus allowed more space for the formation of a thin dendritic crystallization of the gold. This was further con- tinued down the inner surface of the phial, and was there sufficiently thick to admit the impression of minute but distinct crystalline facets. A small crystallized lump of gold lay at the bottom of the phial, but I believe this had been originally attached to the rest, and merely fallen by its weight, as I have since observed to be the case in another portion. Around the stopper, and along the flaw, there was a saline concretion, which tasted like sal ammoniac, and as ammonia was kept in the same cupboard, it had probably united with the muriatic acid as it exuded. Upon finding this specimen, I examined some other metallic solutions, and found a similar separa- tion of the metal had taken place, in a phial containing a solution of platina, and in another containing a solution of palladium. In both these cases a thin, interrupted, and dendritic lamina of metal might be seen between the stopper and the neck, but the crystalliza- tion had proceeded no further. I unstoppered the phial containing the platina, and the lamina (as might have been expected) imme- diately disappeared in the form of a slight muddy film. The palla- dium I still possess. Probably this phenomenon maybe of frequent occurrence ; but as the separation of the metal does not often extend below the neck of the phial, it may have passed unnoticed. These facts, if multiplied, may perhaps serve to throw some light upon the mode in which the dendritic laminae of native gold, silver, &c., are formed in rocks f. It would have been satisfactory to know whether, in the case de- scribed by Professor Henslow, any lard, wax, or lubricating matter had been originally applied to the stopper of the phials, which could have caused or promoted the effect of reduction. The Professor has not before met with any cases of reduction in the crystalline form of gold from solution in acid. These, however, are not uncom- mon. We have specimens of gold finely crystallized, by gradual reduction and deposition, from an ethereal solution of its chloride ; and both gold and silver, and also other metals, may be reduced » Aunalen der Physik, xv.; 145. f Mag. Nat. Hist. i.; 146. Chemical Science. 177 from these solutions in acid, and crystallized, by leaving pieces of charcoal, phosphorus, &c., in them. — Ed. 12. SALICINE — ITS POWER AS A FEBRIFUGE. — (Leroux.) A very important Memoir by M. Leroux, which was presented to the Academy of Sciences, has been most favourably reported upon by MM. Gay Lussac and Majendie. It relates to nothing less than the discovery of a principle in indigenous plants which may replace quinia and cinchonia as medical remedies. Being aware that the willow had been employed advantageously as a bitter and febrifuge, M. Leroux sought in it for some active principle, and ultimately sent two preparations to the Academy, one called salicine, the other sulphate of salicine. He at first thought the new principle was a vegeto-alkali, but when afterwards in Paris, he convinced himself that it had no power of neutralizing acids, did not combine with them, was rendered uncrystallizable by them, contained no nitrogen, and was not a vegeto-alkali. The sulphate was a mistake. Salicine is in the form of very fine nacreous white crystals, very soluble in water and alcohol, but not in ether; it is very bitter, and partakes of the odour of willow bark. In order to obtain it, three pounds of the bark of the willow (salix helix), dried and pulverized, is to be boiled in fifteen pounds of water, with four ounces of carbonate of potash, for an hour ; it is to be filtered, and, when cold, two pounds of solution of sub-acetate of lead added: when settled, it is to be filtered, treated with sulphuric acid, the rest of the lead pre- cipitated by sulphuretted hydrogen, the excess of acid neutralized by carbonate of lime, again filtered, the liquid concentrated and satu- rated by dilute sulphuric acid, then boiled with animal charcoal to remove colour, filtered hot, crystallized repeatedly, and dried with- out access of light. About one ounce of salicine will be obtained in the large way; probably twice the quantity would result, for great loss is occasioned by the above numerous operations. It may be pre- served in well-closed bottles, and does riot attract moisture. As to the medicinal powers of this substance, M. Majendie states, that his own experience of its effects in intermitting fevers is favourable, and that he has seen three doses, of six grains each, stop a fever. He quotes the experiments of MM. Miquel, Husson, Bally, Girardin, Cognon, &c,, at the hospitals and elsewhere, in its favour : they all agree in its anti-febrile power, and in stating that from twenty-four to thirty grains of salicine will arrest the return of the fever, whatever may be its kind. This is nearly the same as the dose of the sulphate of quinia. In concluding, the commissioners state, that M. Leroux has discovered in the willow (salix helix), a crystal I izable principle which approaches sulphate of quinia in its anti-febrile power, and that this discovery is, without contradiction, one of the most VOL, I. OCT. 1830. N 178 Foreign and Miscellaneous Intelligence. important that has fyeen made for many years in pharmaceutical chemistry*. 13. PREPARATION AND COMPOSITION OF MALIC ACID. This curious vegetable acid has been obtained pure and crystallized by M. Liebeg, and carefully analysed, for the purpose of setting the discordant results of different chemists at rest. The expressed juice of the ripe fruit of the mountain ash was boiled with animal char- coal, which had previously been purified by muriatic acid ; and a certain quantity of potash added, but so as to leave a great excess of acid ; the whole evaporated till thick as syrup, then mixed with five or six times its volume of spirit of wine, and the clear, vinous liquor, after separation from the mucilaginous matter, distilled. The thick viscid residue of the distillation was again acted upon by alcohol, which entirely did away with the mucous state. Being again distilled, the residue was diluted with much water, precipi- tated by acetate of lead, and the malate of lead obtained, decom- posed in water by sulphuretted hydrogen. The addition of potash and treatment by alcohol has for its object the separation of tar- taric acid and tartrate of potash, which occurs in the original juice, and which otherwise would have given a mixture of tartaric acid with the malic. As directed, the malic acid can contain only citric acid, or traces of tartaric acid ; when concentrated, therefore, am- monia is to be added in quantity insufficient to neutralize the liquor ; alcohol, equal in volume to the liquid, is to be added also, and the whole allowed to cool, when quadrangular crystals of the acid malate of ammonia will be obtained, the salt being very little soluble in alcohol, even though diluted. These dissolved in water, precipitated by acetate of lead, and the precipitate decomposed by sulphuretted hydrogen, yield pure malic acid ; which will be found to crystallize by evaporation in the air, forming, first, acicular cry- stals, and ultimately a solid crystalline mass. A crystallized malate of zinc was then formed, resembling in properties that described by M. Braconnet. By a heat of 212° it loses ten per cent, of water, without change of form ; at 248° it lost other ten per cent., then becoming a white coherent powder. By analysis, the salt gave 46.734 malic acid, 32.711 oxide of zinc, 20 . 555 water, the oxygen of the oxide, water and acid being as 1:3:4. Hence the equivalent of malic acid is 57 . 3, hydrogen being unity. The malate of silver is anhydrous at 212°, and composed of 66.975 malic acid, 33.026 oxide of silver per cent., which gives the equivalent number of malic acid as 57.2. When the dry salt is decomposed by heat, it blackens only for an instant, and yields carbonic oxide gas, which burns like alcohol, and contains no empyreumatic matter. * Ann. de Chiraie, xliii.,440. Chemical Science. 179 The acid malate of ammonia was then decomposed in the manner adopted by MM. Liebeg and Woehler, with the hippuric acid*. It gave azote and carbonic acid in the proportion of 1 : 8, indicating four atoms of carbon in the acid. The hydrogen was determined by burning the dry malate of zinc with oxide of copper, and collect- ing the water by chloride of calcium. The results came out as 4 atoms carbon, 24 ; 2 hydrogen, 2; 4 oxygen, 82; =58: but as this was too high, as compared to the conclusions respecting the equivalent number, and as it was the same with the composition of dry citric acid, excess of hydrogen was suspected ; and as a trace of water in the salt used would account for this excess, other experi- ments were made with the anhydrous malate of silver. This salt gave little more than one atom of oxygen, and the composition of malic acid may therefore be considered as follows : — 4 atoms carbon . . 24 1 „ hydrogen . . 1 4 „ oxygen . . 32 Equivalent number . 57f 14. ULMIN, OR ULMIC ACID, AND AZULMIC ACID. The following points relative to the history of ulmin are abstracted from a thesis by M. P. Boullay on this subject. This substance derives its importance from the numerous circumstances which give rise to it, and the daily conversion of numerous vegetable matters, especially those in wood, into it. Its existence in vegetable earth, in manure, and in the sap of plants, shews the important part which it performs, and it is probably the most valuable compost known. It occurs in enormous quantities in brown earth, turf, &c., and Hol- land probably owes the superiority of its agricultural productions to the quantity which it naturally possesses. M. Boullay has considered it as an acid, and gave it a corre- sponding name, because of its power of combining with bases. It was first found by Vauquelin in an exudation from the elm tree ; M. Braconnot formed it artificially. It is produced in the distillation of wood in soot, and may be formed by the action of sulphuric and muriatic acids upon many vegetable substances. Ulmic acid differs from the substances produced by the action of air or oxygenizing bodies, on extracts, tannin, gallic acid, or gallates, both by its colour and solubility in alcohol. It is more probable, from the properties of the resulting substance, that when gallic acid or the gallate of ammonia is exposed to air, a new sub- stance, not sufficiently examined, is produced. The composition of ulmic acid is the same as that of dry gallic acid, but it has a much feebler saturating power ; its equivalent number is to that of gallic acid as 5 : 1. It has been analysed by * Quart. Jour, of Science, vol. vii. p. 424. f Ann. de Chim. xliii. 259. N 2 180 Foreign and Miscellaneous Intelligence. Boullay, and gallic acid by Berzelius ; the proportions they obtain are as follow : — Ulmic Acid. Gallic Acid. Carbon . . 56.7 57.08 Water . . 43.3 42.92 equal to three proportions oxygen, three hydrogen, and six of carbon. Hence it was supposed, that gallic acid differed only in water of crystallization, but all attempts to deprive it of water, and convert it into ulmic acid, failed. The ulmates of the metals, although insoluble in saline so- lutions and in excess of ammonia, are, when well washed, soluble in water, like the ferro-prussiate of iron. They take fire at a tem- perature much below a red heat, and burn. Three of them were found by experiment to be composed, per cent,, as follows : — Oxide of Silver. Of Lead. Of Copper. 28.57 . 26.86 . 10.5 Ulmic acid 71.43 . 73.14 . 89.5 Hence the equivalent of the acid consists of fifteen proportions of oxygen, fifteen of hydrogen, and thirty of carbon, which, taking hydrogen as unity, is 315. This is precisely five times the number of gallic acid. The feeble capacity of saturation possessed by ulmin may, per- haps, be important in nature, for a large quantity of this food of plants may in consequence be transmitted to them from decomposing substances, by small quantities of alkali or ammonia. The earthy ulmates, and especially that of lime, are not quite insoluble, and withal are capable of being suspended so perfectly in fluids as to be useful in the nutrition of plants, whilst still they are not so likely to be washed away as the soluble ulmates. Azulmic Acid. — By this name M. Boullay designates a substance which has the same kind of relation to ulmic acid that azoted organic matter has to such as is of vegetable origin. The carbonaceous product left by the spontaneous decomposition of hydrocyanic acid is azulmic acid, and not a carburet of azote. It contains hydrogen, and can combine with salifiable bases in the same manner as hydro- cyanic acid itself. Azulmic acid is not soluble either in hot or cold water or alcohol : strong cold nitric acid dissolves it, forming a reddish solution, precipitable by water. The alkalies dissolve it very freely, producing deep-coloured solutions : the acids precipitate these solutions, as do also the metallic salts. By heat azulmic acid gives first hydrocyanate of ammonia, then cyanogen, and leaves carbon. When analysed, the proportion of azote to carbon was in volumes as 2 to 5. Hence, upon theory, it will consist by weight per cent, of 47.64 azote, 50.67 carbon, and 1.69 hydrogen. Pursuing the analogy between ulmic and azulmic acid, M. Boullay endeavoured to form the latter by heating gelatine with potassa, in imitation of M. Braconnot's process for forming ulmin ; and, in fact, azulmic acid appeared to be produced. Azulmic acid is pro- Chemical Science, 181 duced also not only by the spontaneous decomposition of hydrocyanic acid, but by those of hydrocyanate of ammonia, of cyanogen dissolved in water, by the action of cyanogen upon bases, and indeed whenever compounds of this substance are experimented with. The action of weak nitric acid on cast iron, or the carbon it contains, produces a similar substance ; and as azulmic acid appears to combine with concentrated nitric acid, there is reason to believe that artificial tannins are only combinations of this body with nitric acid, or at least that they contain an analogous substance*. 15. ON GASEUM AND MILK. — (Braconnot.) An excellent, because practical memoir on milk has been published by M. Braconnot, in the Annales de Chimie, xliii. 337, which offers many applications of a substance long but not thoroughly known, not a few of which we anticipate will hereafter come into use. This substance is caseous matter, or, as he has called it, caseum. Soluble Caseum, and its Applications. — 2500 parts (grammes) of the curd of new cheese, as sold in the market, were heated to 2 12° for some time : it contracted, and became a glutinous elastic mass, swimming in much serum. Being washed in boiling water, to re- move the acid serum, and dried, it weighed 469 parts. It was a compound of caseum with acetic and lactic acids : being divided, put into sufficient water with 12.5 parts of crystallized bicarbonate of potassa, and heated, it dissolved with effervescence, producing a mucilaginous liquor, distinctly reddening litmus paper. Being evaporated carefully, with continual agitation, it left a soft portion, which, as it cooled, acquired consistency, was drawn out between the fingers into thin portions, and then dried in the air upon a sieve : it weighed 300 parts. This soluble caseum is a surcaseate of po- tassa, containing still butter and salts. It resembles isinglass, is of a yellow-white colour, translucent, and of a stale taste : it is per- fectly soluble in hot or cold water, producing a fluid rendered milky by the presence of butter. In this impure state the substance is easily prepared : instead of the bicarbonate, the potash or soda of commerce may be used. The following are hints for its application. Like gelatine, it may be preserved without alteration for any length of time, and may be obtained in enormous quantities, if required. Associated in various ways with food, it must prove of the greatest importance on board vessels for long voyages. Its aqueous solution, sugared and fla- voured with a little lemon-peel, makes an agreeable and nourishing drink for invalids. It is a powerful cement : its solution, evapo- rated on glass or porcelain to dryness, cannot be removed without injury to the vessels ; its hot concentrated solution has been applied with great success to join glass, porcelain, wood, and stone. The same solution forms a brilliant varnish : being applied to paper, it • Annales de Chimie, xliii. 273, 162 Foreign and Miscellaneous Intelligence. makes labels, which, when moistened and attached, adhere with great force. It may be used instead of isinglass in dressing silks, ribands, gauze, preparing artificial flowers, &c. It has not answered in endeavours to clarify beer, but is equal to milk or cream in the clarification of table liqueurs, giving them the softness and qualities of age. It may be used in place of creamed milk in the clarification of beet-root, sugar, syrups, &c., in conjunction with animal char- coal, without exciting any fear regarding the presence of serum. M. Braconnot thinks also, that by the help of a little ammonia the greater part of the curd previously separated as above from its serum may be taken up and converted into a dry substance, which, with the help of earthy salts, will be of great service in clarification : for, having dissolved some of this preparation in water, a small quantity of muriate of lime, sulphate of magnesia, or even sulphate of lime in powder was added : the liquid remained clear whilst cold, but the slightest effect of heat made it coagulate uniformly throughout ; the coagulum gradually contracted, and a perfectly clear liquid issued from it. Milk has always been considered as a certain antidote in some cases of poisoning. The soluble caseum will perform the same office against most of the metallic salts, but there is reason to believe that white of egg is better than either against corrosive sublimate. Chemical Properties of Caseum. — Caseum is an acid which, because of its tendency to combine with almost every substance, it is very difficult to obtain pure. The soluble caseum already de- scribed is to be dissolved in boiling water, put into a funnel, the aperture of which is stopped, and left until a layer of cream has collected on the surface. After removing this, a little sulphuric acid is to be added, which will form a clot of sulphate of caseum : this is to be well washed and then heated in water, with just enough carbonate of potash to dissolve it. The mucilaginous liquor formed is, whilst hot, to be mixed with its volume of alcohol. It is neces- sary that no deposit form at the moment ; it should occur only in the course of twenty-four hours, and will include the butter, the sulphate of potash, and part of the caseum. All is to be placed on a cloth, and a clear transparent liquid will pass, which, evaporated to dryness, leaves caseum pure, except in retaining a minute portion of potash. Caseum, or caseic add, thus obtained, is a dry diaphanous sub- stance, resembling gum arabic in appearance, and unalterable in the air. It reddens litmus paper, is soluble in hot or cold water, forming transparent viscid adhesive solutions, yielding by evapora- tion transparent pellicles, which again dissolve in water. The mi- neral acids, except the phosphoric, when added to the liquor, unite to the caseum, and produce white, opaque, coagulated, insoluble masses. Very weak solutions are not thus coagulated, as may be seen by adding a little diluted sulphuric acid to such ; heat does not Chemical Science. 183 cause the effect, but the moment a little lime is added it happens at once. Milk with twice its bulk of water is not coagulated by sul- phuric acid cold, but apply heat and the effect is produced, because a little phosphate of lime in the milk then becomes sulphate, and acts as above. Generally, the combinations of cheesy matter with acids are irnputrescent. Well washed sulphate of caseum was left with water for a long time : it gradually disappeared, but produced no putrid odour. Vegetable acids precipitate caseum, unless in excess. Potash, soda, and ammonia produce very soluble compounds with it, which are perfectly transparent, unalterable by air, and resemble gum. All earthy bases and metallic oxides form insoluble compounds. All salts, except those with base of potash, soda, or ammonia, combine with caseum to form insoluble compounds. Even a little selenitic water put into a solution of caseum, though it causes no change at first, yet, when heat is applied, produces insoluble pellicles, which are a compound of the caseum and earthy salt. The same or still more striking coagulation happens with sulphate of magnesia and acetate of lime. Strong alcohol does not affect caseum ; weak alcohol dissolves it. Sugar renders a solution of caseum more liquid : gum arabic renders it quite insoluble, probably from the presence of earthy salts in it. Infusion of galls acts with it as with gelatine. M. Braconnot sus- pects that vegetable albumen is nothing more than caseum with some earthy salts present. Improved Milk. — Besides caseum and butter, milk contains salts, &c. which are not particularly desirable. M. Braconnot took 2J litres (4.4 pints) of milk, heated it to 113° F., gradually added dilute muri- atic acid, and agitated the whole. The curd formed contained the caseum and butter, and, being separated from the whey, was gradu- ally mixed with 5 grammes (77 grains) of crystallized sub-carbonate of soda, reduced to powder and warmed. No water was added, but the whole gradually dissolved. It had the weak acidity of recent milk, and formed about a half-litre of cream (a fifth of the first bulk), capable of numerous applications in domestic economy. If made up to its first bulk with water and a little sugar, it forms a milk more agreeable than the original; or it may be flavoured, &c., and used as cream. If it be heated with about its weight of sugar, it becomes remarkably fluid, and forms a perfectly homogeneous syrup of milk, which will keep for any length of time, and which, by the mere addition of a sufficient quantity of water, forms a perfectly homogeneous white opaque liquid, which is in every respect like sugared milk of improved flavour. The syrup diluted with water forms a nourishing drink for invalids. Carefully evaporated, but not beyond a certain limit, or the butter would separate, it gave, when cold, a soft confection, which left for a twelvemonth in a loosely stopped bottle, underwent no change. This, when exposed in thin portions to the air, was rendered quite dry, and could then be crushed 184 Foreign and Miscellaneous Intelligence. and kept for any length of time without change, being always recon* vertible into useful states by the mere addition of water*. 16. MANUFACTURE OF CHARCOAL. A new process, recommended in the Journal des Fore/5, for this purpose, is to fill all the interstices in the heap of wood to be charred with powdered charcoal. The product obtained is equal, in every respect, to cylinder charcoal ; and, independent of its quality, the quantity obtained is very much greater than that obtained by the ordinary method. The charcoal used to fill the interstices is that left on the earth after a previous burning. The effect is produced by preventing much of the access of air which occurs in the ordinary method. The volume of charcoal is increased a tenth, and its weight a fifthf. Mr. Doolittle, of Birmington, United States, has lately charred wood in kilns constructed for the purpose. One was built of brick- work, thirty feet diameter and nine feet high, to the opening of the arch which inclosed the top. It had openings at the top and sides for the purpose of admitting air, charging, extracting, &c., all which openings were under regulation. The charcoal thus obtained was exceedingly good in quality, free from stones, earth, &c., and very abundant in quantity, the increase being, in the latter respect, some- times half as much more as the old mode of burning would givej. 17. POTASH OBTAINED COMMERCIALLY FROM FELSPAR. According to M. Fuchs, this important alkali may be extracted from minerals containing it, by the following method : — They are to be calcined with lime, then left for some time in contact with water, and the liquor filtered and evaporated. M. Fuchs says he has thus obtained from nineteen to twenty parts of potash from felspar, and from fifteen to sixteen from mica, per cent§. 18. SALE OF SELENIUM. Perfectly pure selenium (free from sulphur) is announced for sale, at the price of four gold Frederics (ninety francs) per ounce of Cologne (446 grains). Applications, post paid, with the money, is to be made to the Ducal Office of the Mines of Harzgerode, in the duchy of Anhalt. * Ann. de Chim. xliii. 337. f Bull. Univ., D. xiv. 262. J Silliman's Journal, xvii. 395. § Ann. de 1'Industrie, v. 278. Natural History, #c. 185 § III. NATURAL HISTORY, 8fc. 1. MECHANISM OF THE HUMAN VOICE IN SINGING. A memoir on this curious subject has been read to the Academy of Sciences by M. Bennati, and examined by MM. Cuvier, Prony, and Savart. The former of these three philosophers has reported thereon to the Academy. The principal object of the memoir is to make known the powers of an organ in effecting the modulations of the voice, which in this point of view has been little attended to by physiologists. This is the soft palate, or the narrow part of the gullet formed above by the uvula, at the sides by the arches, and at the bottom by the root of the tongue. M. Bennati has succeeded in constructing an instrument which can include three octaves. He points out in his memoir the precautions which should be taken in this respect for the instruction of young persons destined to be vocalists; amongst one of the principles, is, to interrupt the exercises at the period when the voice changes. M. Bennati concludes his memoir by this proposition, that it is not only the muscles of the larynx which serve to modulate the sounds, but also those of the os hyoides, of the tongue, and of the veil of the palate ; without which all the degrees of modulation necessary in singing cannot be attained. From hence it results that the organ of voice is an organ mi generis, an instrument inimitable by art, be- cause the materials of its mechanism are not at our disposal, and we cannot conceive how they are appropriated to the kind of so- norousness which they produce. This result, although not entirely new to science, appears to the reporters to be proved by M. Bennati by new facts and observations, and to have acquired such develop- ment as to fix the attention of physiologists*. 2. GLOBULES IN THE HUMOURS OF THE EYE. MM. Ribes and Donne have lately discovered globules in the humours of the eye, of a smaller size than those of the blood. There are three orders of them : the first are in sinuous chaplets, and very apparent ; the second are isolated, larger than the others, aud surrounded by a black circle ; the third are least distinct, arid resemble a kind of mist. The authors are disposed to question the utility of so many parts of the visual organ in the production of impressions on the retina. It is known that the removal of the crystalline lens by extraction does not destroy vision. The rays of light must be considerably modified by the globules of the humours t. * Revue Ency. xlvi. 502. f Archiv. General. Medical Journal, v. 148. 186 Foreign and Miscellaneous Intelligence. 3. USE OP NITROGEN IN RESPIRATION — CYANOGEN IN THE BLOOD. Dr. Rich, Professor of Chemistry in the Vermont Academy of . Medicine, has put forth a view of the part which nitrogen performs in respiration, to produce cyanogen, which then exists in the blood as cyanide of iron. He quotes the observations of others, by which the nitrogen of the atmosphere is shewn to be absorbed in respi- ration, and also occasionally given out again in the lungs, and he thinks there is no more difficulty in conceiving that it should enter into the blood in the pulmonary vessels, and combine with the carbon in the blood, just as oxygen does. Cyanogen would probably result; and then, referring to the ordinary processes by which Prussian blue is obtained from dried blood, Dr. Rich seems to consider it just as likely that the process should merely transfer the cyanogen already existing, as that they should cause its formation from the carbon and nitrogen present. This view appears to him to explain the difference which has existed amongst chemists relative to the presence of iron in the blood. Englehart's process of detecting iron in the fluid blood, or rather in the colouring matter of the blood, namely, by passing chlorine through it for a time, and then testing the clear solution, he conceives to depend upon the chlorine taking away the cyanogen from the iron, and so bringing the latter into a state indicative by the usual tests *. Dr. Rich has not had the opportunity of supporting his views by any experiment, although he suggests some. We cannot help ob- serving that the idea of the cyanogen obtained by the Prussian blue maker being merely that which pre-existed in the blood, appears to be a very violent one. The quantity he can obtain from dry blood is enormous, many times surpassing the weight of the co- louring matter in it. Further, the colourless serum will yield plenty ; and now, in fact, blood is but seldom resorted to for it, but hoofs, horns, and other sources of animal matter, are used for the purpose. 4. ACTION OF THE PILE ON LIVING ANIMAL SUBSTANCES. Being desirous of testing by experiment the opinion often enter- tained and advanced, that secretions in the living body are the result of electrical decomposition, M. C. Matteucci applied the poles of a voltaic pile containing fifteen pairs of plates, to two wounds made on the lateral parts of the abdomen of a rabbit, so as to leave the peritoneum bare. The poles were of gold, and it was soon found that a yellow alkaline liquor, containing many bubbles of air, col- lected at the negative pole, whilst a yellow liquid with few bubbles and slightly acid, collected at the positive pole. When the positive pole was copper, it became covered with a green coat slightly acid ; the same results were obtained by acting upon other parts of the * Silliman's Journal, xviii. 52. Natural History, 8fc. 187 body, as the liver, intestines, &c. The substance obtained at the negative pole besides alkali, contained much albumen and coagu- lated by heat ; the fluid at the positive pole also contained a highly uzotated substance. These experiments M. Matteucd considers as supporting the opinion advanced above ; and considering the secreting viscera in different feeble electric states, it is easy to conceive the production of acid and alkaline substances characterizing the secretions, and to understand the formation of new substances by the combination of the nascent elements. The electric state of the organ secreting particular fluids may also be deduced ; and still further it might be expected, that alkaline secretions would contain substances in which hydrogen and carbon formed the principal part ; whilst acid secretions would contain bodies abounding more in oxygeu and azote. A brief consideration of the analysis of those substances which are found in the urine, milk, bile, saliva, &c., will shew generally the truth of this deduction *. 5. ON THE DISORDERS ARISING FROM THE LONG-CONTINUED USE OF IODINE. — (Dr. Jahn.) The following is the account which Dr. Jahn gives of that diseased state of the system, which results from along continued or excessive use of iodine, and which it will be found differs much, as do also the explanations of the effects, from the descriptions of MM. Coindet, Gardiner, Sceter, &c. When introduced into the organic fluids, iodine acts firstly and principally upon the process of nutrition. The first evident effect is an absorption of the fat, so that a gradual leanness is remarked. At the same time, we may observe with a little attention, an aug- mentation of all the excretions. The skin, in consequence of an increased deposition of carbon upon it, appears dull and of a livid hue ; there is great and clammy perspiration ; respira* tion is obstructed, the urine is increased in quantity, and the surface of it is often covered with an oily pellicle. The alvine evacuations are increased, and the faeces are loaded with bili- ous matter and contain but little mucus ; the seminal secretion is increased, and also the menstrual discharge. * It is clear/ says M. Jahn, ' that in this state the vitality of the veins and lymphatic vessels is exalted, and the predominance of venous excitement is shewn, by the swollen state of the superficial veins, and the blue colour of the lips. The blood, it-may be inferred from the diminished redness of the skin, and the feebleness of the arterial pulsations, has acquired a more serous character, and is more liquefied, so that the quantity of serum is greater in proportion to the cruor and fibrine. The energy of the irritable tissues is comparatively diminished. Hence the patient is more easily fatigued than before; digestion is * Arm. de^Chimie, xliii. 259. 188 Foreign and Miscellaneous Intelligence. irregular, the saliva and mucus are diminished, and complaint is made of dryness of the mouth and throat. The nervous power is also materially affected, and symptoms resembling hysteria and hypochondriasis arise, morbid sensibility, lowness of spirits, timidity, sensation of weakness, trembling of the limbs, similar to that pro- duced by mercury, agitated sleep, with disagreeable dreams, &c. At this period irregular and transient febrile attacks announce a reaction of the constitution. If now the morbid condition be not opposed, and if the iodine be continued, the above symptoms in- crease in severity, and shortly the glandular tissues, the breasts, testicles, and thyroid gland are diminished in substance. At length, all those symptoms arise, which are said to constitute nervous con- sumption. M. Jahn has examined two bodies, which presented the traces of the action of iodine. A woman, who having misused the remedy, was attacked with enteritis, which proved fatal; and a man affected with cancer of the stomach, who was treated by the internal and external use of iodine, and who took very large doses of the tincture secretly, in hopes of a more speedy cure. In the bodies of these patients the fat had disappeared, the various tissues had a withered and flabby appearance, the glands were shrunk and soft, and also the mesenteric ganglia (which are usually much developed in cancer of the stomach), the thyroid and supra-renal glands, the liver, spleen and ovaries. Notwithstanding the mischief sometimes inflicted by the use of iodine, M. Jahn considers it one of the most valuable remedies which has been recently discovered*. 6. CHLORINE AN ANTIDOTE TO HYDROCYANIC ACID. MM. Persoz and Nonat have verified the favourable results which M. Simeon had obtained relative to the remedy which chlorine affords against prussic acid. They operated upon three dogs, upon the eyes of which a drop of prussic acid had been placed. Dividing the symptoms into three periods, namely ; i. uneasiness, ii. tetanus, iii. interrupted respiration : they found that when chlorine was applied in the first period, the relief was immediate, the respiration became regular, vomitings and alvine discharges occurred, the animal gradually regained its strength, rose unsteadily, and, in about half an hour, was as lively as at first. Applied at the second period, the symptoms were arrested, but the restlessness continued awhile ; and though respiration was less painful, the convulsive movements continued for ten minutes, then occurred vomitings, &c., as before, and, at the end of an hour, the animal was perfectly well. The two dogs thus treated being tried next day with the same quantity of prussic acid, but without chlorine, died in a few minutes. * Med. Jour., xlix., p. 72. Natural History, fyc. 189 In the third case, all the effects of the prussic acid were pro- duced before the chlorine was applied ; the respiration had ceased for twenty-five seconds, and the animal was rapidly perishing ; but the chlorine not only recalled it to life, but ultimately restored it to full vigour : the full effect only occurred, however, after some hours. Ten days after it was quite well, and the paralysis of the abdominal parts, which occurred in all, had, in this case, entirely disappeared. After this, MM. Persoz and Nonat sought to ascertain whether the prussic acid, being absorbed into the vessels and tissues, the chlorine would follow and decompose it. Two dogs of equal strength were taken, the crural veins laid bare, and separated from the neighbouring parts, and especially the accompanying nervous fibres; then a drop of prussic acid was put upon each vessel. The effects were instantaneous ; a few drops of chlorine (solution) were let fall on to one of the crural veins — the other animal was left alone. The first was as immediately recovered as it was injured ; the second died directly. The first felt no inconvenience after some hours, except from the wound. Endeavours were then made to kill him, by putting prussic acid upon the eye and upon the crural vein of the opposite side ; but the animal only felt temporary inconvenience and a few convulsive movements, and was very quickly at ease. Hence it appears that the chlorine administered beforehand is taken into the circulation, and is then an effectual remedy against prussic acid. Trials made with the chlorids of lime and soda, in place of chlo- rine, shewed that they possessed no corresponding powers, being quite inert as antagonists to the hydro-cyanic acid *. 7. ON THE CURE OP ANIMAL POISONS, AND PROBABLY HYDRO- PHOBIA, BY THE LOCAL APPLICATION OF COMMON SALT. (Rev. J. Fischer.) The Rev. J. G. Fischer was formerly a missionary in South America, and is anxious to call the attention of the public to the probable utility of common salt, as a remedy in cases of hydropho- bia, if at least the opinion be correct, that what will cure the bites of venomous serpents will be efficacious in the former class of cases. He says, * I actually and effectually cured all kinds of very painful and dangerous serpents' bites, after they had been inflicted for many hours; for immediately after I had applied my remedy the pain subsided, and the patient calmed, which remedy was nothing else than common table salt; and I kept it on the place or wound, moist- ened with water, till all was healed, within several days, without ever any bad effect occurring afterwards. I, for my part, never had an opportunity to meet with a mad dog, or any person who was bitten by a mad dog ; I cannot, therefore, speak from experience, as to * Ann, do Ckimie., xlui., 324. 190 Foreign and Miscellaneous Intelligence. hydrophobia, but that I have cured serpents' bites always, without fail, I can declare in truth.' Mr. Fischer then quotes Dr. Urban's practice from Hufeland's German Medical Journal. He had six methods, but his most suc- cessful was to apply a thick pledget, soaked in any saline solution, to each wound, or to each place where the teeth had made a mark without breaking the skin, and retain them there by bandages. The best solution is of salt, one ounce, or one ounce and a half, to a pound of plain water, and the wounds are to be kept constantly moistened with it. The lint is to be renewed and soaked twice a day ; the places wetted every two hours, and even washed by the patient, especially if any indications of relapse, as itching or pain, should manifest themselves. A case is then quoted from the Kent Herald, and Morning Herald of July 28, 1827, as follows : * A friend of ours was some years since bitten by a dog, which a few hours afterwards died raving mad. Immediately upon receiving the bite, he rubbed salt for some time into the wound, and, in consequence, never experi- enced the least inconvenience from the bite, the saline qualities of the salt having evidently neutralized the venom, and prevented, in all probability, a melancholy death by hydrophobia.' That which induced Mr. Fischer to try the above remedy, in the case of serpents, was ' a page of the late Bishop Loskiell's (with whom I was personally acquainted), in his History of the Missions of the Moravian Church in North America, which says, as far as I recollect, that at least among some tribes, they were not at all alarmed about the bites of serpents, having always in use such a sure remedy as salt for the cure of them, so much so, that they would suffer a bite for the sake of a glass of rum. It was this that induced me to try the cure of venomous bites with salt, and the trial has exceeded my expectations.' ' P. S. The advice of killing all dogs is neither practicable nor necessary : apply salt to man and dog, the bitten and the biter, all will be most probably well *.' &c. 8. ON RESTORATION FROM DROWNING BY INSUFFLATION OF THE LUNGS. At the sitting of the 22d May of the Royal Academy of Medicine, M. Piorry reported the results of his experiments on the insufflation of the lungs of living rabbits, of the lungs of sheep, and man, after death. He concluded, first, that insufflation seldom causes rupture of the lungs unless too long and too violently continued ; that death is caused by a mixture of air and blood in the heart, or by a double hydrothorax, or by the distension of the abdomen; that this insuffla- tion may cause subpleural but not interlobular emphysema; and that insufflation of the digestive tube is almost as promptly mortal as that of the lungs by preventing the descent of the diaphragm and impeding respiration. Secondly, that crepitation always indicates * Me