u} x eee ore = &ii Ah, j 3 fit nen , ch Spc Saye ae THE ANNALS PHILOSOPHY. NEW SERIES. JULY TO DECEMBER, 1826. VOL; -XIL AND TWENTY-EIGHTH FROM THE COMMENCEMENT. ESRI cr mes London : Printed by C, Baldwin, New Bridge-street ; FOR BALDWIN, CRADOCK, AND JOY, PATERNOSTER-ROW. eB 1826. | ee wit Bete 5 Die cea TABLE OF CONTENTS. Te es — -NUMBER I.—JULY. Dr. Colquhoun on a new Form of Carbon 6. 4i.0.0 6... eeec eee ee eee es cong | Rev. Mr. Powell’s Remarks on some of Mr. Ritchie's Experiments on DUAR TRONE cee Lin vinka skas some oiwe kes vie e SWHIVUNG. 2 ALTA ATS 13 Mr. Miller on the Production of Acatia CUE sos ois inves 3 O8 Cid P. IVA eolpy Mr. Miller on the Oxidation of Palladium. ...:.06..5 0000000000505 v7h2 “SO Mr, Miller on the Vapours which render Platinum red-hot........022... 94 Dr. Christison’s Reply to Mr. Phillips .... 00.00.00 0.0. 0c cece ccc ce aeee 23 Mr. Christie on the Magnetism of Iron arising from its »s Rowe. (With a Plate.) continued .....-..-. te asians Wanna Bi wn etatahe ORES Ta, SUI OS 27 Analysis of Acorns...... Sao nie Bh. AMIE SOE, BO Ae 43 Mr. Horner on the Use of continued Fractions. with iiinbdertbted Nume- rators in Summation of Series (concluded). ...0s.086.00cceeccueceeess 48 Col. Beaufoy’s Astronomical Observations .............0 00000 cece cece 52 Analytical Account of the Philosophical Transactions of the Royal Society of London, for 1826. Parts I. and Il. (concluded)... .......... 52 ne of the Royal Society ..... seuss vanentnn cd ee P08; Prete mre 61 oe Royal Institution. sis cvssiceasaesceayss Bee OT Geological Society. .....0¢.:cccce8. Swans Soon chee 67 _ On the Absorption of Gases by Liquids. .........0.45. giged As FUP 69 ‘ deat. Drummond's Stationclight: 0... 6 FM Poe Oe EN 74 Butter in a Bog. .... SDs os Se A DWSUE MOTTE CUBR a ees ‘aendcetacod sims. Luminous Meteor. ..... hse dices eal Pad HeeeNab i sancti igde Nc Gieiccarldtecoun insider incaiaa ede 75 New Scientific Books . ..:..... Brag * + sien pian Shaye tehveuralnenanhe iain 296 Mier eben iF oS seca cca os Mera eK oo cab ee SE OEE Ovlocesun cae Be ais hy § Mr. Giddy’s Meteorological J ournal ...... swewall. bend sa pas daccaate basis’? 998 Mr. Howard’s Meteorological Journal. .... beadasioasal). dave eqecdin. eee FO eee NUMBER 11L—AUGUST. Rev. Mr. Emmett’s Account of a curious Phenomenon observed in the Ne oe re ea eee Sok ee ees Lae ul one's «alls bem v0.9.0 6 Ra's ee | M. Chladni’s New Catalogue of Wheialites, PACED EEL 0g 0. sa Awsinie'so kiv.ao 83 Mr. Herapath on the Quantity of Vapour in the Atmosphere, and the MII MHTRVIRICS CEN TRIUEL STC ce ecco hy cess cE bR stds dante edgyes 07 Mr. Gtay on the Genus Hinnita OPEDG Fiance. oo os ag kon o's vga e ies ohn ia: 108 Mr. Christie on the Magnetism of Iron arising from its Rotation (continued). 106 M. Berzelius’s Analysis of some Minerals........ FEN 00 sats Tighe detnle « coves. TS iv CONTENTS. On Excessive Heat in America during the Summer of 1825. ....+.0000« Rey. Mr. Ritchie’s Reply to the Rev. Mr. Powell ...........0.000. ins Statement of a Plan for making a minute Survey of the Heavens .,...... Analytical Account of the Philosophical Transactions of the Royal Society of London, for 1826. Parts I. and IL. (continued) ...........0e0005- Proceedings of the Astronomical Society. ........+eceeeeeereeseeeeres Linnean Society......... Ai ii,» viviownille sien 'a Biersiae 0 Geological SOrety. 00.0555 is pice sine pwhidiomh cipinvores bie Wernerian Natural History Siciwy. i dois SHES Ed Medico-Botanical Society of London. 6..sWei cds. Crystallization of Sulphur. ........ steraioe oo w¥e be UAE. as owe JEUY sé Meconiate of Morphia. .0..0.0.00, Lkadnabssibe U6 QU IIUUULS UE TUS Ie ares On the Use of Common Salt and Sulphate of Soda in Glass-making .. Inspiration, of Hydrogetay; apisicediiexalacigs Ai OULITE VO Se Intelligence from the Land pis Expedition, under Capt: Franklin and . Dery Righardspnjods i anciad psfeisde BOLL 0 wuiat get ith use Stereotype Printing .........ssc+eesceceeee ee bedecss 00 6 OI GETS On an Air-pump, without Artificial Valves bid tammiedonae 4 dQee 3h 20. ta Hardening of Steel Dies........ceessecsvseeeeseeee Ve So GOd We TSE re Cutaneous Absorption. ....... « bebibones pO 10 NOU RIEUIUE, OF S00 Animal Magnetism in France.......2..seeesees Wie OLeOs ss 4 TOLGGHS Fossil Megalosaurusand Didelphis... ..........0sceeeeeeeees fo. boosted Heart of the Frog used for Poison. .......0c i. cccecc cece cele tbdccule se oe ‘Raming Rattle-anakes _ ¢ oes. s2.00 0502 o9ae cbUUeoee MGen Se. 12 CEOIUIT New Scientific Books............ PR et EL wih. vereves.s errr. New Patents . .........0 orneesss sethmaiv, Jcsimalua). sweverworrrres Mr. Giddy’s Metentolonical Journal:. sbispiF ad cous’ TonoipandA oak : Mr. Howard’s Meteorological Jourmal.....sacsseseceecesseeene NUMBER m1 .-—SEPTEMBER. Dr. Colgnhoun? s Cheaiicil Essay on the Art of Baking Bread Potter act Messrs. Babbage and Herschel’s Account of the Repetition of M. Arago’s: Experiments on the Magnetism manifested by various Substances dur- ing Che Act of Rotation... on... ve es de sch isi seshsauecab eres etec ces Mr. Brayley on the Rationale of the Formation of the Filamentous and Mamillary Varieties of Carbon; and on the probable Existence of but two distinct States of Aggregation in Ponderable Matter. ............ | Mr. Faraday on the Mutual Action of Sulphuric Acid and Naphthaline, Gl Gah dew “Acid PRUE sec sc ccs oe as. bh cre wegeenncden ins. 4s Analytical Account of Prot, Daubeny’s work, on active aol extinct Vol- of Philosophical Transactions of the Royal Society of London, for 1826. Parts I, and LI. (concluded) ..........cecceeces , 124 161 183 226 CONTENTS. Vv q. | Page Proceedings of the Astronomical Society. ......é:c0s eeeeedevsssncess 280 Solar Spectrum—Light and Heat... 0.0... 0.22 ce ceeeee ces dviewied. £01. 234. Luminous Circle around the, Moon ......0.ceseeeeeoeeeen sees Losliddwe 236 Geckoes used! for‘ctitehiing Flies... ii dic icc c ices ce adie since warenidivcee 27 On the Serpents of Southern Afficas ....... sess beereeeee eens wie siete sie. 207 Manner of the Serpent-Eater (Gypogeranus) in destroying Serpents...... (237 New Species of a North American Quadruped: ............0.0eeeeees +» 238 New Scientific Books........sceseseeceses ase bO. bp bald. Mar-amitmuted 239 fl heheal ee ICRRE CGE EEDECE ET ere We 8 whore do Hackh: vedvsicctite on 821 Mr. Scanlan on theincidental Formation of the Compound of Hyponitrous _ and Sulphuric Acids, lately examined by Dr. Henry....-.........002. 334 vi CONTENTS, Mr. Phillips's Answer to Dr. Christison’s “ Reply..)....0.2..). os 335, Rev.J.B. Emmett’s Telescopical Observations'on the Moon’. )...).0.) 2387 Mr. Goldingham on the Pendulum at the Equator pip vA peel gale Mis Pelletier.on Cafein. ....cccveccsecvececdcpestebicoteves pnd to aey 354 Mr. Sturgeon on an improved Rlectso-naapibtla ‘Apparatus. (with a Plaka): 2ST AGT oth Re Toad Pia mre ee y i AY SEOISES 357 Mr. Gray on the Genus Hinnites ..4... 0.000.000 00000000008. “ ar ... 861 Mr. Graham on Alcohol derived from the Fermentation of Bread. « .. 863 Mr. Levy on the Tungstate of Lead ..ceceasisiscseeseseees Shes ss ae 364 Mr. Meikle on the Law of Temperature... ../...... re 6 Mr. Stephens’s Suggestions for the Improvement of the British System of CpUs SUEEM a tho cw cahe set ceneen once ess taences +6 nahee aan 369 M. Balard on a peculiar Substance contained in Sea Water. Br Arras ise" -- 381 Proceedings of the Medico-Botanical Society of London................ 387 On the Confinement of Dry Gases over Mercury. ohn seaees sents, Se CRG T aS 500s: ovgdachecroseretneds Cp wnedara ss Seances a eno og cc pe, oteD Lodine found in the Mineral Spring of wohaidiiari near Leith ...... 0... 890 Fluidity of Sulphur at common Temperatures . 2.2... 0.02... cece eee “890 TOGSRRCIINT ETAT OCC ob on cwcins saan oni ve entsss seat heacnratet shares 391 Analysis of Halloyite ........ Mint mmanananie aah deit ainnin gous he hess 584 391 Cold: produced by Combination of Metals. ...,..........ceeeceeeeeeees 392 Notite on the Digestive Organs of the Genus Comatula of Lamarck, and on the Orinvidea of Mullet .... 2.0.60 ec. gece eseesmepereregeccees . B92 Rplendid Collection of Shells. .o.ee eee econ ceceeccncccoes 304 New Scientific Books................ deem RU ian hada § taxon n't Saas aioe 394 ayy a one pea enn, Salad ius hc wists A bbhan ea: 45, a Mr. Giddy’ s ‘Meteorological Journal ......,...... eblke és geRsUADed «5 seve 396 Mr. Howard's Meteorological Journals,..........+se0+eeeeseesersseeae 397 eve eee tion of an Iron Plate, ideveb . In order to find the points which I have mentioned, I adjusted the instrument’ so that the plane of the fixed limb was’ exactly in the magnetic meridian, and then brought the other limb into | the same plane: the centre of the plate was then on the magnetie meridian, and its plane perpendicular to that plane, asrepresented in fig. 1. I now made the plate revolve in its own plane about the axis Bd, and noted very carefully its effect on the needle. In doing this I found that if I placed the plate on the arm, so that a certain point, ¢ for instance, coincided with the plane of the limb, the deviation was different when the same point, by the revolution of the plate, coincided with the limb agaiti.: As it appeared by this that the revolution of the plate had an effect upon the needle, independent of the partial magnetism of parti- eular points, I considered that if the plate were made to revolve the contrary way, the deviation ought to be on the opposite side, and this I found to be the case. I will'illustrate this by the observations made when I first noticed the effect. The plate was divided at every 30° of its circumference (fig. 2) by lines drawn through the centre, and being placed on the arm, so that 0° eoknliaed with the upper part of the limb, the north end of the needle pointed 10’ east; but when this point again coincided with the limb, by the upper edge of the plate revolving from west to east, the needle pointed 30’ east: making the plate revolve the contrary way, that is, its upper edge from east to west, when 0° coincided with the limb, the north end of the needle pointed 28’ west: so that there was a difference’of 58’, when every point of the plate had the same position with respect to the needle, according as the plate was brought into that po- sition by revolving from west to east, or from east to west. As this appeared extraordinary, I made repeated observations at the time to ascertain that the effect was independent of any acci- dental circumstances, and found that the results always accorded with the first, the difference caused by the rotation of the me bate however greater or less according to the position of the plate. | ramet 4 1826.]; oo ainising frown its Rotation.) 31 Having fully satisfied myself that, in whatever manner'the rotation of the plate might cause this difference, such was really the effect, I next endeavoured to ascertain the nature and degree of the difference, according to the different situations of the centre of the plate. . For this purpose I made a great variety of _ experiments, of which I shall.not however here give the details, as | afterwards repeated them in a more convenient manner, and with greater precision; but shall merely point out the nature of them in general, and the conclusions which [at the time drew from them... The instrument’ being adjusted, and the arm fixed so that the centre oi the plate was in the position ‘which I required, I made the plate revolve so that its upper edge’ moved from west to east, and noted the greatest:and least deviation: of the north end of the needle; I then made the correspondin observations when the plate revolved in the contrary direction } a mean of the differences between the two greatest and between the two least I considered as the effect produced on: the needle by the rotation of the plate in opposite directions. »Repeatin these in a variety of positions, L found that when: the centre ‘o the plate was inthe magnetic meridian, its: plane being always a tangent to the sphere circumscribed about the centre of the needle, the deviation of the needle caused by the rotation of the - plate in its plane,was the greatest when the centre of the plate was in the equator, and that it decreased from there towards thé poles, whereit was nothing; * that when its centre was on the equator, this deviation was the greatest when the centre of the plate was-on the meridian, or in longitude 90°, and decreased to nothing in the east and west points, or when the longitude of the plate was 0° or 180°; and that when the centre of the plate was in the secondary both to the equator and meridian, the. rotation of the plate, whatever might be its latitude, caused’no deviation of the needle, In)these experiments, the plate which I made use of was a circular one 17-88 inches in diameter, -and: ‘099 inch in thickness, weighing 112. 0z. .The further 1 had pursued this inquiry, the more I was disposed to attribute the effects | haye mentioned to a general magnetic action, arisihg in a peculiar manner from the rotation of the iron; and my next experiments were with the view of ascertaining how farthis idea was correct, As similar results might not be obtained with any other plate, 1 next made use.of a plate 12:13 inches in diameter and :075 inch in thickness, weighing 38:75 oz. and with it obtained results precisely of the same nature, though consider- _ ably less in quantity. Another. objection which occurred to me’ a * I should here mention, that, from the nature of my instrument, I could not make observations at the north pole; but as the results, as far.as I could observe, were of the same nature on this side of the equator as on the south side, I think I am warranted in- concluding, that af the north pole the results would likewise be of the same nature as at the south pole,” 5 wits 32 Mr. Christie on the Magnetism of Iron’ = (Jury, was this—that the iron being evidently slightly polarized in par- ticular points, the effect might be supposed to arise from an impulse given to the needle by the motion of these points in a particular direction, and that the directive power of the needle not immediately overcoming the slight friction on the pivot, a deviation might thus arise from the rotation of the plate. Had this, however, been the cause of the deviations, I should have expected that, when the centre of the plate was in the meridian, the greatest effect would be produced with the plate parallel to the pho and its centre vertical to that of the needle; but I had seen that the greatest deviation took place when the centre of the late was in the equator, its plane being perpendicular to it; and the deviation arising from the rotation, when the plate was parallel to the horizon, was not a fifth of the deviation when the plate was perpendicular to that plane. Besides it was manifest that if this were the cause, any other impulse would have a similar effect. I therefore made the needle revolve first in one direction, and then in that opposite, by means of a small bar-magnet, and invariably found that it settled at the same point, in whichever direction the impulse was first given, and the results obtained by the rotation of the plate were iu these cases of the same nature as before. It was also evident, that if the deviations I have mentioned arose from this ‘circumstance, the needle being agitated after any particular point of the plate was brought to the limb of the instrument, it ought to settle in the same direction, whether that point were brought into this posi- tion by revolving from east to west or from west to east ; but this, except in the cases I have mentioned, where the rotation pro- duced ne deviation, was not found to take place. In order wholly to obviate this objection, in all my future experiments, after any point had been brought to the limb of the instrument, I Sgiteted: the needle, and let it settle before I noted the devia- tion. | | “ Description of particular Experiments. ‘ As I had found in my first experiments that I could obtain the nature of the deviation caused by the rotation by noting the reatest and least deviations when the plate was made to revolve in contrary directions, but that the quantity of that deviation could not by this means be determined with any degree of pre- cision, I resolved to make my future observations differently. The method I adopted, when the change in the deviation from one point of the plate to another was considerable, was this: the plate being placed in any required position, I made it revolve once, for example, the upper edge boon east to west, without noting the deviations, bringing the point marked 0° to coincide with the line indicating the position for observation ; from hence I continued the revolution of the plate until the point marked * 1826.) . 9 arising from its Rotation.» > oo 30° coincided with the same line, and, after slightly agitating the needle, noted the deviation; and in the same manner were the points 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300°, 330°, 360°, or 0°, brought successively to coincide, and the deviations noted. I now madé the plate revolve once from west - to east, without noting the deviations, bringing 0° or 360° to coincide with the same line, and then brought in succession 330°, 300°, 270°, 240°, 210°, 180°, 150°, 120%; 90°, 60°, 30°, 0° to coincide, noting the deviations as before. The sum of the first set divided by 12, I considered as the mean deviation, when the plate revolved from east to west ; and the sum of the others divided by 12, as the mean deviation, when the plate revolved from west to east: their difference was the mean effect of the rotation in contrary directions., This I call the Deviation due to Rotation; and to distinguish it from the deviation caused simply by the position of the iron, I call this last the Absolute Devia- tzon. When the change in the deviation from one point of the plate to another was not so considerable, [ made the observa- ‘tions, only for the points 0°, 90°, 180°, 270° on the plate. .. “I now proceed to the detail of the experiments, and the conclusions I draw from them. In those which I shall first describe, the centre of the plate was always in the magnetic meridian ; its plane was perpendicular to the meridian, and a tangent to the sphere, whose centre was the centre of the needle; and the plate revolved, as in all other cases, in its own plane: they are a repetition of those by which I first discovered several of the facts I have mentioned, but made for the purpose of deter- mining more precisely the deviation caused by the rotation. In making these, the instrument was adjusted so that the index at g, fig. 1, pointed to 0°, that at K to 90°, and those at 0, 0’ to zero.” Mr, Christie now gives a table of observations, the results of which he states as follows: ‘«From these observations it appears, that when the centre of the pias was in the pole of the magnetic sphere, its plane being parallel to the equator, the position of the needle, for any situa- tion of the several points of the plate, was the same whether they were brought into that situation by the plate revolving from east through south to west, or from west through south to east ;~ thatis, that the deviation due to rotation was nothing : “That the deviation due to rotation increased from this point towards the equator, where it was the greatest : _ And that the horizontal needle was affected by the rotation of the plate, not according to the situation of the centre of the pips as regarded the poles and equator of the horizontal needle, ut as regarded the poles and equator of an imaginary dipping ‘needle passing through the centre of the horizontal needle. — ~ © This last is not so evident, from the circumstance of the New Series, vou. X11. D | 34 Mr. Christie on the Magnetism of Iron [JuLy, deviation being nothing when the centre of the plate was in the pole of the dipping needle, and a maximum when in the equator, as from its being very nearly equal at equal distances on each side of the pole, and also of the equator; that is, at very unequal distances from the axis of the horizontal needle ; and from the deviations at equal distances from the axis of the horizontal needle being very unequal. For if we compare the deviation due to rotation in lat. 70° 30’ 8, long. 90°, with that in lat. 70° 30’ S, long. 270°, the difference is only 1’; in the first case, the centre of the plate was at the distance of 90° from the axis of the hori- zontal needle, and its plane parallel to it; and in the other at the distance of 51°, and its plane making an angle of 39° with this axis, Again, in the four corresponding situations of lat. 19°30’, the mean deviation due to rotation is 1° 32’, and none of 'the deviations differ from this by more than 5’, although in two cases the centre of the plate was in the axis of the horizontal needle, and its plane perpendicular to it, and in the two others the centre of the plate was at the distance of 39° from this axis, and its plane made an angle of 51° with it. The mean of the deviations due to rotation in the three* corresponding situations of lat. 45° is 49’, from which none of the deviations differ by 3’, notwithstanding the difference in the situations of the centre and plane of the plate, in these cases, with tion to the axis of the horizontal needle. In long. 90° lat. 45°, the centre of the plate was 64° 30’ above the horizontal axis, and its plane made an angle of 26° 30’ with it; in long. 90° lat. 45° N, it made an wtisle of 64° 30’ at 25° 30’ below it; and in long. 270° lat. 45° S, it was.in a position above it similar to the last. Any doubt, however, on the subject will be removed, if we compare the deviation in long. 90° lat. 39° N with that in long. 270° lat..0; the one deviation Being nearly double of the other, although the centre of the plate was at the distance of 19° 30’ from the axis of the horizontal needle, and its plane’ made an angle of 70° 30’ with it in both cases. The difference is even more strik- ing, if we compare the deviation in lat. 70° 30’ 8, long. 270°, with that in lat. 31° 30’S, long. 90°, the centre of the plate being in each case et the distance of 51° from the axis of the horizontal needle, and its plane making an angle of 39° with it. The differences which we have noticed inthe deviations observed at the same distance from the equator, is not more than I have found to arise from a slight change in the adjustment of the centre of the needle to the centre of the instrument, the plate remaining in the same position. These errors of adjustment I found it almost impossible to avoid, owing probably in a great ‘** The nature of the instrument would not admit of observations being made so near to the north pole in long. 270° as lat. 45°, or so near as lat. 70° 30’ on the other side of the support G I.” 1826.] arising from its Rotation. 35 measure to the magnetic centre of the needle not being in the centre of suspension ; and it was to counteract their effects, that I generally made observations on contrary sides of the centre. “ With respect to the direction in which the deviation due to rotation took place, it appears, that the rotation of the plate always caused the north end of the needle to move in the same direction as the edge of the plate nearest the south pole of the magnetic sphere ; su that the deviation of the north end of the needle was in the direction in which the south edge of the plate moved, and that of the south end of the needle in the direction in which the north edge moved, referring the edges to the poles of the sphere. _* Having ascertained, that when the centre of the plate was in the pole, and its plane parallel to the equator, the deviation due to rotation was nothing; and some of the first experiments which I had made having indicated that this was also the case when the centre of the plate was in the secondary to the equator and meridian, and its plane, as before, a tangent to the sphere, I wished to ascertain whether such were really the fact.” The experiments made accordingly, the results of which are given in another table, left no doubt in Mr. C.’s mind on the subject, and from them, combined with the preceding, * we may infer, that if the centre of the plate were made to describe _any parallel of latitude, the deviation due to rotation would be nothing when the longitude was 0° or 180°, and a maximum when the longitude was 90° or 270°, which is precisely the reverse of the absolute deviations that would be produced by the plate describing the parallel of latitude. : _ © The next experiments which I made were with the view of determining whether the rotation of the plate would produce any deviation, when its plane coincided with the equator. For this purpose an axis was fixed perpendicularly on the arm’ of the instrument in such a manner, that when the plate revolyed on it, its plane was parallel to the limb. ‘In otder to make these observations, it was necessary te adjust the whole instrument twice ; since the deviations for the _ longitudes 90° and 270° could not be observed with the same adjustment as those for the longitudes 0° and 180°. For the longitudes 90° and 270°, the axis of the instrument was hori- zontal, and pointed east and west, and the moveable limb revolved on the axis until its plane, and therefore also that of the iron plate, made an angle of 90° 30’ with the horizon, rising towards the north; so that the compass being elevated until the centre of the needle was in the plane of the plate, the plate was then in the equator. For the other longi- tudes, the axis of the instrument was inclined to the horizon at an angle of 19° 30’, and in the plane of the meridian ; and the moveable limb adjusted at right angles to the fixed one: the D2 36 Mr. Christie on the Magnetismof Iron [Juny, compass was then elevated to coincide with the plane of the late. : ee In these experiments the distance of the centre of the iron from the centre of the needle was 13-2 inches; but as its edge was only 4:26 inches distant, the differences between the devia- tions corresponding to the several points on the plate were greatly increased ; and therefore to obviate any inaccuracies that might arise, from the points not being brought into precisely the same situation when the plate revolved in the opposite directions, I increased the number of observations, making twenty-four for each position, namely, twelve points on the plate, as I have before described, the deviation for any point being observed when that point coincided with the line joining the centre of the plate and needle.” The obseryations on this subject, which are given in a third table, “ show very clearly, that when the centre of the plate is in the equator, and its plane also coincides with the plane of the equator, the deviation due to rotation is always nothing, since the small differences to be observed here in the revolutions in oppo- site directions are only such as may justly be attributed to slight “errors in the adjustments of the centre of the needle or of the plane of the plate, which are almost unavoidable. With regard to the several deviations in the different columns, I should notice that they are not those actually observed, but derived from them by subtracting the same number from all the deviations observed in two corresponding columns, so that they indicate the same difference of deviations in the two revolutions as those actually observed, and therefore give the same deviation due to rotation. ‘The necessity of this reduction arose from the circumstance of my having to adjust the compass to the proper height, so that its centre might be in the plane of the plate, while it was under the influence of the partial magnetism of particular points in the plate and having done this, when zero of the compass was rought to coincide with the point of the needle it was not necessarily in the magnetic meridian, since the needle was under the influence of this partial magnetism; and as I wished the deviations to be those from the meridian, I reduced the observed deviations as I have mentioned. “ Being convinced that the rotation of the plate in the plane of the equator caused no deviation of the rhedlle. I proceeded to determine the effects produced by its rotation in other planes. In the first set of observations which I made, the centre of the plate was in the meridian, and its plane perpendicular to the plane of-the meridian and passing through the centre of the needle. Before however making these, to avoid the necessity of moving the compass as in the Tast, I made a slight alteration in the instrument. Instead of haying the axis on which the plate revolved perpendicular to the arm, and the plate conse- 1826.) \ arising from its Rotation. 37 quently paralle] to the limb, this axis was inclined in such a manner that the plane of the plate passed through the axis of the instrument; so that the axis of the instrument being hori- zontal, and passing through the centre of the needle perpendicu- larly to the meridian, when the arm of the instrument was adjusted to zero on the limb, the revolution of the limb caused the centre of the plate to describe the magnetic meridian, and at the same time the plane of the plate always passed through the centre of the needle. The distance between the centre of the plate and that of the needle was, as in the last, 13:2 inches.” “* From these observations I find, directly contrary to what took place when the plane of the plate was a tangent to the sphere, that the deviation due to rotation increases from the equator to the pole, where it is a maximum. In this case, how- ever, as in the other, the deviations are very nearly equal at equal distances on each side of the equator; so that, as before, it appears that the horizontal needle was affected by the rotation of the plate, not according to the situation of the centre of the plate with respect to the poles and equator of the horizontal needle, but with respect to the poles and equator of an imaginary dipping needle passing through the centre of the horizontal needle. . “ With regard to the direction of the deviation due to rotation, it appears, that when the centre of the plate had north latitude, the north end of the needle deviated tn the direction of the motion of the plate’s inner edge; and when it had south latitude, the north end deviated ina contrary direction to that of the inner edge of the plate, and therefore the south end deviated in the direction _ of the anner edge: so that the end of the needle of the same name as the latitude, always deviated in the direction of the motion of the plate’s inner edge. ~ | : _ Let us compare this with the inference we have drawn from the observations, viz. that when the centre of the plate is in the meridian, and its plane a tangent to the sphere, the north end of the needle, by the rotation of the plate, deviates in the direction’ of the motion of the south edge, and the south end in the direc- tion of the north edge of the plate; that is, either end of the’ needle deviates in a direction contrary to that of the motion of the edge of the plate nearest to the pole of the sphere of the’ same name as that end. Now, if from the position which the plate had in the last experiments, namely, its plane passing through the centre of the needle, it be conceived to revolve about its diameter, which is perpendicular to the plane of the meridian, until its plane be a tangent to the sphere, the direc- tion of the revolution about this diameter being of the inner’ edge towards the pole of the same name as the latitude of the’ plate’s centre, the inner edge will become the edge of the same name as the end of the needle, which, in its first position, 38 Mr. Christie on the Magnetism of Iron [Jouy, according to our inference from the last observations, deviated in the direction of its rotation; but according to the inference drawn from the first series of observations, the end of the needle of the same name as this edge, will, in the new position, deviate in a direction contrary to that of its rotation; so that the rotas tion of the plate being in the same direction in. both positions, the deviations by rotation will be in contrary directions .in the two cases; and consequently, between the two positions, the plane of the plate must haye passed through one in which the rotation would produce no deviation. If we conceive the plate to come into the position of the tangent-plane by revolving about its diameter in the opposite direction, that is, by the inner edge moving towards the pole of a contrary name to the latitude, the inner edge will become the edge of the contrary name to the end of the needle, which in the first position deviated in the direction of its rotation; and therefore that end of the needle will still continue to deviate in the same direction; that is, the direction of the rotation being the same in the two positions, the deviation by rotation willbe in the same direction in both cases ; and consequently between the two positions, either there is no position of the plane of the plate in which the rotation will produce no deviation, or there are two, or some even number of such positions. ~ « J have not been able to determine in all cases experiment- ally, the situation of the plane in which the deviation due to rotation vanishes, or whether there may be more than one plane in which this takes place ; but all the observations which I have made confirm me in the opinion which I formed on comparing the preceding results, that when the centre of the plate is in the meridian, there is only one plane between the tangent-plane and the plane passing through the centre of the needle in which the deviation due to rotation vanishes, and that that plane is parallel to the equator, “‘ Another conclusion which ‘we may draw from these experi- ments compared with those above referred to, is this, that when the centre of the plate is in the meridian, and its plane perpen- dicular both to the meridian and equator, then, supposing the plate always to revolve in the same direction, the deviation will always be in one direction, in whatever point of the meridian the centre of the plate may be. _ “ As I had already found, that when the centre of the plate was in the secondary to the equator and meridian, and its plane a, tangent to the sphere, the rotation caused no deviation of the horizontal needle : it appeared.to me that there ought to be no deviation due to rotation when the plane of the plate was in any other plane perpendicular to this secondary. To ascertain how far my views were correct, or otherwise, I adjusted the plate on the arm, the same as in the last experiments, and the instrument 1826.) arising from its Rotation. 39 so that the axis AQ, being in the plane of the meridian and inclined to the horizon at an angle of 19° 30’, the centre and plane of the plate were, during the revolution of the limb, always in the position I required. The distance between the centres o the needle and plate was, as before, 13°2 inches.” ; “ Although the deviations due to rotation in these observations are in some cases greater than might perhaps on a first view be expected, if in the position in which I have supposed the plate, its rotation would really produce no deviation, yet the differ- ences are not in any case more than may, I consider, be fairly attributed to errors in the adjustments. That the deviations, when the plate révolved from south to north, had a tendency most generally to be greater than when it revolved in a contrary direction, as is evident by referring to the Table, appears at first sight more unfavourable to my opinion than the magnitude of the difference ; but on further consideration, I think that this will be allowed rather to point out the source of the errors in the results, than the incorrectness of my views, and that these errors arose from the plane of the plate not being in those cases perpendicular to the plane of the secondary to the equator and meridian. The proximity of the edge of the iron to the ends of the needle, varying from 5:16 inches to 4:27 inches at the south end, and from 5:16 inches to 5:92 inches at the north -end, I considered to be another source of error ; the inequalities arising from. the effects. of particular points near the edges of the iron on the ends of the needle being the more sensible when the distances are small. .All my observations were made as near to the centre of the needle as the instrument would admit, in order that the effects of the rotation, since they were in many cases extremely small, might be the more sensible ; and by this means I discovered the nature of the effects produced on the needle by the rotation of the plate; but I am fully convinced, that for the purpose of comparing the results of observation with the conclu- sions from theory, it is always desirable, that the observations should be made when the iron is at such a distance from the centre of the needle, that the effects of particular points near its edges, on the ends of the needle, are nearly insensible. Taking these circumstances into consideration, [ was quite satisfied from these experiments, that, if the centre of the plate be in the secondary to the equator and meridian, and its plane perpendi- eular to the plane of that circle, the rotation of the plate will produce no effect on the absolute deviations caused by th mass. | - In order to determine what effects would be produced by the rotation of the plate when its centre was in the secondary to the equator and meridian, and its plane in the plane of this circle, the instrument was adjusted as in fig. 1, the index at g pointing to 70° 30’; the limb 8 AL N was then placed at right angles to 40 Mr. Christie on the Magnetismof Iron = [Juty, SQN, and the arm A B attached ‘to it with the iron plate on the axis; and that the centre of the needle might be in the plane of the plate, the compass box was moved in the direction of the meridian, , “Some of my first observations were made with the centre of the plate in the equator, and I immediately found, that the deviation due to rotation, instead of being 0, as in the cases when the plate revolved in the planes at right angles to its present osition, was here considerable ; and also that, that of the south end of the needle was in the direction of the upper, or south edge of the plate, age to what had been observed in the same plane at the pole. This indicated that there must be, at Jeast,, one point in this circle on each side of the pole, where the deviation due to rotation was 0; and to determine nearly the latitude of this point, I made observations at every 10° of lati- tude on each side of the south pole. Before, however, giving these observations, it is necessary that I should state the kind of reliance I place on them as forming a complete set. In order to make the observations near the pole, it was necessary to adjust the instrument with the axis horizontal and pointin east and west, and after having made the complete set, suspected that in the change from the one adjustment to the other, the centre of the plate had been nearer to that of the needle in making the observations near the equa« tor, than those near the pole ; and that consequently, the devia- tions due to rotation in the former case, were proportionally too great; I was confirmed in this suspicion on comparing these observations with those which I had, in the first instance, made in lat. 0° and in lat. 90°; and still further on comparing them with others, which | subsequently made at the several distances 15, 17, 19, 20 inches; in the corresponding situations. For example, in my first observations, the deviations due to rotation in lat. 0°, long. 0°, and in lat. 0° long. 180° were 3° 10’, and 3° 14’, giving a mean 3° 12! in lat. 0; and in lat. 90 8, 1°31’; when the centres of the plate and needle had been carefully adjusted to the same distance 13°2 inches, in the two cases; whereas the corresponding deviations in the table are 5° 43’ and 1° 291’; and, by subsequent observations, I found the sum of the deviations at the distances 15, 17, 19, and 20 inches to be in these two cases, 7° 20’ and 3° 32’, to which 3° 12’ and 1° 31’. are very nearly proportional. These differences however do not in the least affect the conclusions which I at the time drew from this set of observations.” “It appears, from these observations, that when the plate revolves in the plane of a secondary to the equator and meri- dian, “1st. The deviation due to rotation is a maximum when the centre of the plate is in the equator. WoO 3 1826.}) - arising from its Rotation. 41 . ~ 2d. It decreases as the plate approaches the pole, and is 0 between the latitudes 50° and 60°, apparently very nearly at 55°; and from this point it increases till it attains a maximum in a contrary direction at the pole. » “3d. Atthe south pole and on each side down to the latitude 55°, the deviation of the south end of the needle due to rotation is in the direction of the north or lower edge of the plate; or, from the south pole down to the latitude 55°, the sowth end of. the needle moves towards the plate, when the tnner edge of the late moves from the south pole, and from the plate when the imner edge moves towards the south pole. fer ' “4th. From the equator towards either pole as far nearly as the latitude 55°, the south end of the needle moves in the direc- tion of the south edge of the plate; that is, it moves towards the plate when the znner edge of the plate moves towards the south pole, and from the plate, when that edge moves from the south pole; also the north end of the needle moves éowards the plate, when the znner edge moves towards the north pole, and from the plate, when that edge moves from the north pole. Consequently towards whichever pole the zner edge moves, the corresponding end of the needle will move towards the plate from the equator to the latitude of 55° nearly, and the contrary will take place from the latitude 55° to the pole. “‘ The observations which I made with the plate on the north: side of the equator, though not so multiplied as those on the south, were sufficient to show, that the deviations due to rota- tion observed the same laws on that side of the equator as I had noticed’on the south side. “The deviation due to the rotation of the plate, when its centre is in the secondary to the equator and meridian, having a pecu- liar character, namely, two greater maxima when the centre is in the equator, two less maxima, in a contrary direction, when the centre is in either pole, and four points where it vanishes, I consider to be particularly well adapted for forming an estimate of the correctness of any theory which may be adopted for the explanation of the phenomena mm general ; since the theory must be perfectly compatible with these peculiarities, before it can be applied to the explanation of the less marked phenomena. _ As it appeared from these observations, that the point where the deviation due to rotation vanishes, is not far from lat. 55°, the complement of which, 35°, is nearly half the angle of the dip; I wished to ascertain whether the deviation were really _ 0 in latitude 54° 45’, which I considered to be correctly the complement of half the dip 70° 30’, although I could not see how the angle which the plane makes with the horizon could: have an influence on an angle in the plane itself. Subsequent observations showed, that in this instance the deviation due to. rotation vanishes, or nearly so, when the polar distance of the 42 Mr. Christie on the Magnetism of Iron, &c. [Iuur; centre of the plate is equal to half the angle which the dipping needle makes with the horizon. Whether this coincidence is purely accidental, or is a necessary consequence of the manner mn which the effect is produced, must remain doubtful, , until it can be shown how the action takes place; it, however, led me to ascertain precisely the point at which the deviation due to rotation vanishes.” | * General Law of the Deviation due to Rotation deduced from the Experiments. “Having now ascertained the nature of the effects produced on the horizontal needle by the rotation of the plate in different planes, [ endeavoured to discover some general law, according to which the direction of the deviation depended on the direc- tion of the rotation of the plate; so that the situation of the centre of the plate, the plane in which it revolved, and the direction of rotation being given, we might point out imme- diately the direction in which the deviation would. take place. “ On comparing together all the facts which I have detailed, I found that this might be effected in the following manner. 1 refer the deviations of the horizontal needle to the deviations of magnetic particles in the direction of the dip, or to those of a dipping needle passing through its centre; so that, in whatever direction this imaginary dipping needle would deviate by the action of the iron, the horizontal needle would deviate in such a manner as to be in the same vertical plane with it: thus, when the north end of the horizontal needle deviates towards the west, and consequently the south end towards the east, I consider that it has obeyed the deviation of the axis of the imaginary dipping needle, whose northern extremity has deviated towards the west and its southern towards the east; so that the western side of the equator of this dipping needle has deviated towards the south pole of the sphere, and its eastern side towards the north pole. It would follow from this, that if the north and south sides of the equator of the dipping needle (referring to. these points in the horizon) deviated towards the poles, no cor- responding deviation would be observed in the horizontal needle ; the effect, in this case, taking place in the meridian, would only be observable in the angle which the dipping needle made with the horizon. As it is not my intention at present to advance any hypothesis on the subject, I wish this to be consi- dered only as a method of connecting all the phenomena under one general view. Assuming it then for this purpose, it will be found that the deviations of the horizontal needle due to rotation are always such as would be produced by the sides of the equator of this imaginary dipping needle deviating in directions contrary to the directions in which the edges of the plate move, that.edge of the plate nearest to either edge of the equator producing the. 1826.] Analysis of Acorns. 43 reatest effect on it... By referring to the particular laws which [ -deduoed at the time of making the experiments in different planes, it will be seen that they are all comprised under this general law; but this will be rendered more evident by taking an instance. j ) “ When the centre of the plate is in the meridian, and its plane a tangent to the sphere, the eastern side of the equator of the imaginary dipping needle, according to the above law, will deviate in a direction contrary to that of the motion of the eastern edge of the plate, and consequently the northern extre- mity of the axis will deviate in a contrary direction to that of the motion of the plate’s northern edge, or it will deviate in the direction in ahssk the southern edge of the plate moves. Hence the horizontal needle obeying the deviations of this dip- ping needle, the deviations of its north end due to the rotation of the plate will be in the direction in which the south edge of the plate moves, which is the law deduced from the experiments first detailed.” - EE. W.B. “i (To be continued.) Artic.e. VIII. Analysis of Acorns. (To the Editors of the Annals of Philosophy.) - GENTLEMEN, » . I see to inclose the notes made of some experiments to ascertain the component parts of the acorn. Although the analysis is not complete, and I have since found no leisure to supply what is wanting in it; yetit seems to contain some facts on the subject that I am not aware can elsewhere be found; and for that reason you may, perhaps, think the inclosed paper enti- tled to:a place in your pages. Yours, &c. W. B. [We could wish that the experiments of our correspondent had been more complete, as we are not fond of admitting frag- ments into the Annals of Philosophy. We publish his commu- nication, however, in the hope that he will pursue the subject to a satisfactory conclusion.— Ed. ] cent Ewper. 1.350 grains of acorns were triturated in a marble mortar with water (about 21 pints), and passed through a fine hair sieve ; what remained on the sieve, pressed and dried at a heat of about 130° for three hours, was a light-brown matter (B) eg grains. 1 1 eP | (A.) What passed through the sieve deposited a white sedi- 44 * Analysis of Acorn’. [Jury, ment, which, after standing twelve hours,.was separated by ouring off the supernatant 3 wre and after being dried five boars at about 100°, weighed 71 grs. It was digested in dilute nitric acid, and was dissolved in two days; from this it was pre- cipitated by alcohol. . (B.) The 63 grains of dry matter were macerated in cold water two days, and the water (C) being poured off, was dried, and alcohol of commerce added to it, but no part was dissolved, although the colour of it became deeper, and it obtained a more friable and harsh texture. The alcohol being poured off, nitric acid was added, and a partial solution took place ; for at the end of twenty-six days, I found one-third of it dissolved. The solu- tion was decanted off, and evaporated to dryness ; the residue was very soluble in water, and of a wax-yellow. With this solu- tion, muriate of lime gave no precipitate ; muriate of tin, nitrate of silver, acetate of lead, gave each a copious white precipitate. wie This water did not seem to have taken up any part of the 63 grs. | . (D.) The water that passed through the hair sieve was evapo- rated to two ounces, and gluten coaguléted in flakes, which, separated by the filter and dried, weighed 25 grs. Isinglass then precipitated about 10 grs. of tannin, the remaining part was owing to an accident unexamined, © | The composition, therefore, appears to be, ‘ Grains, Starch. eeertes eed BESO VUE VES oes VS 71 Insoluble matter ....6cccccccees + Gh Eee Matee (oC otk Ve tabi Vides ab aaa ot uee Tannin . ee eee Ce ae ee cake Vas eeuek ne 10 Extract, &c. and los$. os. cc ese eeee ISL 350 Exper, 2. Analysis of the Ashes of Burnt Acorns.—The shells, or external coats (not the cups, or calyces), were taken off. Grains, The shelled acorns weighed. ........ 1500 The shells, or coats ....... 5 AY PUNY 360 Total .. eevee 6's Ba CR a eiaidalt we 1860 (A. 1.) The shelled acorns were placed in a brown earthen- ware cup, uncovered at the top, and continued at a red heat for five hours, until burnt to ashes, which weighed, while hot, 20 grs. Upon these ashes, three ounces of water were poured, and after sometime filtered, the insoluble matter on the filter (A. 2.) being’ dried, weighed five grains. The solution (A. 1.) turned turmeric, paper brown. | ; 1826.) Analysis of Atoris. 45 .. This solution was evaporated to dryness, gave ‘a brown deli- quescent mass, to which alcohol was added... The alcoholic solution evaporated to dryness weighed 1-1 gr. and appeared by dissolving in water, and adding nitrate of silver, to be composed of -4 muriate of magnesia and -7 potash. The portion insoluble in alcohol was saturated with dilute nitric acid with efferves- cence, and evaporated to dryness. It weighed 20 grains, and burnt like nitre; 200 grs..of water were added, which dissolved the whole, except °5.gr. which was sulphate of lime. This solu- tion gave no Sis pm with. nitrate of silver, or oxalic acid ; carbonate of potash showed avery slight cloud. It appeared to be nitrate of potash = 19°5 grs. which contain 9°17 of potash. _ Consequently the soluble part (A. 1.) contains e Grains. Carbonate of potash. ...+.sse2+e+e0 88 Potash e@eenreereeeee ee eo eeeeeoevee ove we 5:3 ‘Sulphate of lame. « «0:05 seie.- os + aM? Ye 0:5 Muriate of magnesia. ...... ‘SSoune anes Ow | 150° (A. 2.) The insoluble part being digested in dilute muriatic acid was dissolved, except *5 gr. silex, with a trace of alumine. From the muriatic solution was precipitated the iron by means of prussiate of potash, which gave a precipitate of prussiate of iron of *2 gr. = °1 gr. carbonate of iron ; after adding a drop or two of muriatic acid to the filtered solution, carbonate of potash was added in excess, which precipitated 6 grains of carbonate of lime = 3°4 lime, and on boiling gave a further precipitate of 9) grav carbonate of magnesia. ence the part insoluble in water consists. of Grains ee uk she ok anc ana,< P ae wep ie wey: 0°5 Oe a a Saal i all ag Ne 0-1 a ek oh he Whe ik a ahd». abla aun hte dune 3°4 BEES isn sign Davee shah Al On A nie oo ROMO Xo cc. c,0i dbodiein ich shee San Le GE 0-5 Pc tesa teninen Sik piavel’s trieia’é Mietatwain "125: SOON int ch cltiie's palitece pits OW aninaed law 026 Line of) + a oinictilnaly Gee eden ont 2:0 Magnesia..wcesesoren vlesees osvawe: 6 _ 2°75 Exper. 3. Analysis of Acorns.—5000 grains of epee acorns were pounded in a mortar tolerably fine, and in this state they stood two or three days. The colour of the mass darkened, an became a deep-brown. They were triturated repeatedly in a marble mortar with water, and thrown on a seive, upon which they were well washed with water until it came off colourless : 13 pints of water (E) were employed. It was of a pale leather- brown, and deposited starch (F). {t did not change the colour of turmeric or litmus papers, or of turmeric reddened with an alkali. The insoluble matter (G) still remained of a chocolate colour, and had a chaffy appearance; three pints of cold water (H) were added to it, and put in the oven all night at a heat of about 180°. The water had acquired a deep-brown colour owing to the extract it had dissolved. It was poured off in the morning, having stood about 10 hours. The matter (G) had then a pale leather colour, which soon became darker on expo- sure to the air; two pints more water (I) were then added to it, and it was again placed in the oven for four hours. This water having dissolved another portion of the extract was poured off, and two pints more (J) added, which, having stood in the oven several hours, was, in like manner, poured off, and two more 1826.] Analysis of Acorns. 47 pints added, heated, and poured off. These several portions of water were then poured together. The insoluble matter (G) was then dried at a moderate heat, and weighed 872 grs. / 3 A few grains of this insoluble matter (G) being put into a solution of carbonate of potash, which, after digesting awhile at a moderate heat, dissolved nearly the one-half of it. The solution of extract (H, I, J,) was tested with the following reagents. : Bette Nitrate of silver, a copious deep-reddish brown precipitate, redissolved in dilute nitric acid, leaving a residue. : | Oxalic acid, no change. g is This solution being evaporated to dryness left a deep-brown matter (K), weighing 180 grs. being extractive. 50 grs. of it were put into about an ounce of alcohol of commerce to digest at a heat of about 45° or 50° for seven days, when it had lost 9 grs. of its weight, which were taken up by the alcohol. The alcohol was evaporated, and the residuum, a dark-brown matter, appeared to be apart of (K) altered; for when redissolved in water, it gave with " Nitrate of silver, a precipitate in white flakes. ’ Carbonate of potash, a brown precipitate. — Sulphuric, nitric, and muriatic acid, no change. | Prussiate of potash, no change. | (E.) The soluble matter (E) was poured off the starch (F), which was washed with water, and the washings added to (E) after the starch had subsided. | The starch (F) was thrown upon a filter, and then dried, at a moderate heat, when it weighed 910 grains. ; The water (E) was partly evaporated, and then filtered, It gave a smell resembling mushrooms, and an oily matter floated on the top, of a brown colour.. What was left on the filter (E) was of a glutinous nature, brown, and weighed, when dried, 145 grs. The water was again evaporated, until it was reduced to’ about 12 ounces, when a further precipitate was formed, which was separated by the filter, and weighed 17 grs.(M.) It ae then eyaporated to dryness, and the residuum weighed rs. ) ) ‘ yt Pay this when redissolved in water gave a white pre- cipitate with muriate of tin, acetate of lead, and nitrate of silver. 48 _. Mr. Horner’on ' [Juxy, ArTIcLE IX. On the Use of continued Fractions with unrestricted Numerators in Summation of Series. By W. G. Horner, Esq. (Concluded from vol. xi, p. 421.) 5. The word “much” in the preceding sentence was written inadvertently : a distinction must be made. It will then appear that the gra is most promoted where it is most desira- ble; in the first‘and second Examples, for instance, more than in the third and 4th. The reason is obvious; for any series of slow convergency, such as the former two, or indeed any series which varies little in passing from term to term, can differ but little from a recurring series commencing with the same course of terms. | The mode of estimating the actual degree of approximation has been already noticed. It may not be irrelevant to exem- plify it in this place. The first three terms of the continued . . ide ] P . fraction produce the converging fraction -—— x a. Thenume- rator may be supposed to contain only the first terms of a series 1+P+Q + &c. indefinitely extended; while the denominator 1 + pis complete. The value of p being then found from the Equation Q = 0, and substituted in the expression for R . nr—-ms , (Art. 2), gives R = — —~————- | for the error of the fourth term in the recurring series equivalent 1+P . l+p" The jist five terms produce the fraction a x a; and here, as before, the values of p and q being found from R = 0, and S = 0, produce ek nr—ms 2(nr—ms+rs) ee n+ 2en+3s nedeind te for the error of the sixth term in the recurring series. Example V.—Two varieties of the Binomial Theorem become well tee to arithmetical purposes, by receiving the fractional form. Putting N = the number whose root is to be found, and a, a, eee cecer eset sees (7) to x a; a, a; ten eneee (8) P = the nearest complete power; the first variety is N* = (P +2) = P+ f1-2(p) +2 (Gy G+ which, after the usual reduction (Art. 4), becomes 1826.] the Use of: continued Fractions, Sc. 49 pe $1455 is, Bi y] PEED PR POTRRE AG, PRON Ph (9) * nP+——— ntmer gy 3nP +———— Qntm.ax ; T 5nP ‘+ &e. | The other variety is N= (P — Pr px find) +a G)'= SSenaet G+ n,.2n.3n-° which reduces to OURS HR e He SUL 2 FUNA.S Mod d o¥I9 GIO) Pp” $7 Baath pe = _ x 1+ nN+- Le 5nN + &e. The first or second of these theorems may be used, according as the assumed root is less or greater than the true. It deserves to be remarked, that Halley’s rational method, or the common rule for approximate evolution, is. contained in the first three terms of each ofthese formule. The error, therefore, of that method may be estimated by formula (7). Likewise the general form. of the fraction equivalent to any odd number of terms of the continued fraction will be found to coincide with the formula for (a + 6)" given by Euler in Inst. Calc. Diff. vol. 2, § 239, without investigation. fave wilesd The facility of aggregating a continued fraction, and the opportunities it affords of simplifying its terms, and of making allowance for the effect of the final portion which is omitted, are peculiar recommendations: of the praxis by the continued frac- tions (9, 10) in preference to either of the other modes of evolution. ds’ » Example Vi.—Extract the seventh root of 2. By formula (9), we find (1+1) = | 1 ee et putting y = the neglected part 49 + = + &. = 61 in ihe nearest integers. Hence we have ET Hal «2 7 1 61 1 1 8 11 263 (a=) 223 (as =) 912 1135 79267 —— oo 01.7 10 238 \606 / 202 \1652 — ) 826 1028 71794 13 4 13 (3) (2) 11 79267 a2 ei} 2 hs 4. Wherefore —-5, = 1°10408947 is the root required. New Series, vo. X11. F 50 Mr. Horner on= [JoLy, ' The mode of egating progressively is well known: to the roduct of each prego yg the nanny Which stands over it is added the. product of the next, preceding numerator by the number beneath it in the lowest line; the sum is the succeeding numerator. The denominators are found in the same way. The parenthetic abbreviations are in accordance with the pars of reduction already so often alluded to. mong diverging series, those which Euler. has named — hypergeometrical, present, along with the difficulty of determin- ing their sum, a paradox in regard of the equivalence between’ the series and its sum, which. is only, to be solved by viewing them in relation to recurring series, Thus, having — 1 ’ si ra i el Ke te He +ie.. l+z 142 1432 ul oil). POI eo eaves Trireea sir etee BFlmieH Si 901 EO we infer that making x = 1, the series of fractions a a + &e. converge towards the value of l—1 4+ 2 — 6 + 24 — 120 + 720 — &c. whose sum has been, correctly in this view, determined by Euler to be -56963473, &c. ial | : ) = Lae tt 22% — 4a + 8 atm wane’ The mode of solution employed by that great analyst was chiefly valuable for the new and useful artifices in integration,’ which it elicited from his fertile genius. See Lacroix’s Diff. and Int. Calc. English Edition, § 414, 218. The result was» verified through a widely different process by Dr. Hutton (see: his Tracts). Any solution whatever must, very probably, prove sufficiently laborious ; but it appears to me that that which is” deduced from the principles detailed in this paper, is less operose than either of the above, and leaves less obscurity about the rationale of equivalence. ' Example V\1.—The general hypergeometric series l—-mr+m.im+r.a%t—mimtr.m+t2r.8 + BOY compared with formulz (4, 5,) becomes 3 1 mx eoeerereeeeerereseoeee ee eoeeesreeedbedsneeeeeese (11) L+— rz -— m+r.2 1 : Se 1 +— m+2r,2 i 3rxz 1 +— 1+ see In the particular case already spoken of, m, r, x, are each = 1; whence 1—+14+2+—6 + 24 — 120 + 7200— 4... Soa oa a aie es SA a ~ be beds D4 D4 Dt T+ 4d 4 tees. bese (12) The operations by which the value of this series has been ? 1826.] the Use of continued Fractions, &c. 51 determined at *5963473, &c. as found by Euler and Hutton, are left for the reader’s exercise. They ate very similar to those in the following example, where the coefficients are the continued products of the odd series 1, 3, 5, 7, Se. : Example VII.—If m = 1, + = 2,% = 1, we have S=1-—-14+3-—- 16 + 105— 945 + 10394 — &c. = Wie Res Nae aa 19 gh A nah Sa Soe aon iad Be ag eis bard Reem (13) putting y, as before, to represent the residual portion = Hohe The converging series proceeds thus : D ishrlh 001104 lol+y eel geet Phy. babel Bate | p P P+Wpt Py _ YT? 1? 8? 47 10? 26 °°""** 9? @ Q+i19¢+Qy L. 2, 8.4, Bele 19 15566830368 + 3156467520y _ 486463449 + 98619610 y 23758664096 + 4809701440 y 742458253 + 150303170y — ~ Serviceable limits to the value of y may be thus found. Say, m m+l1 m+2 - ities . bie HN + &c. Assuming this to be generally, y = nearly = = = 1(/ 4m+1 — 1), it is still more nearly = L+y m m+il.y_ m(f 4m+5—1) ‘ j Pe . But if one of these i too great, the other is obviously too little. Use then the mean, or say if ‘ m m+kh.y m(/4m+3—1) yis nearly = 7 ™* 8+! Ses re comic de ama: GA) | ‘3 m m+ (” *8) i : Peer ey PS sh, nln) Vm eT H+ DS - ? | F 20° + Amal se ’ UL ey ack ty ; and there also are one greater and the other less than the correct value of y. When m = 20, these limits are, 20/83 — 1 20 (21 7 87 — 22) (A) === = 395631, (B) == “S79 = 3°95619 876632213 Accounting ..y = 3-9563,we findS = =o = -65562071L ; 2. 876622351 __, The latter is, therefore, the value of the series, very probably correct in every figure ; certainly in all but the last. mn : ie it is still more nearly = f EQ §2 Analyses of Books. ~\ (Jory, ARTICLE -X.” Astronomical Observations, 1826, - By Col. Beaufoy, FRS. Bushey Heath, near Stanmore. Latitude 51° 37’ 44:3" North, Longitude West in time 1/ 20-93”, Eclipses of Jupiter’s satellites. are May 8. Emersion of Jupiter’s first {10h 44’ 40’ Mean Time at Bushey. Satellite. 0... cieebeledenciees 10 46 OL Mean Time at Greenwich. May 15. Emersion ,of Jupiter’s first{12 39 .16 Mean Time at Bushey. Batellite ..6s2 sn sees ceeees (12 40 37 Mean Time at Greenwich. Occultations.of Stars by the Moon. May 12. Immersion of a small star, about ais Cai bs ns the sixth magnitude ....... Lt Ee ee May a Immersion = A 2Cancec..... . IL 55 22-6 Sidereal Time. ay 14. Immersion of a small star, about | , y eis ‘ wee a iesevent me 25 17-3 Sidereal Time. ay 15. Immersion ofa small star, about age : _ the seventh magnitude re 1S * $9 «388 Sideteal Time, May 15, Ingress of Jupiter’s se- [10h 14 10” M.'T..at Bushey.’ Contact... cond satellite...... 10 21 29 M. T. at Bushey. On Planet’s disc. ] ArticLe XI. ANALYSES oF Books. Philosophical Transactions of the Royal Society of London, for | 1826, ed T. and HL. roth Tue first part of the Philosophical Transactions for the pre- sent yearis occupied by Mr.South’s observations of the apparent distances and positions of 458 double and triple stars, made in the years 1823, 1824, and 1825; together with a re-examination of 36 stars of the.same description, the distances and positions of which were communicated in a former memoir by himself and Mr. Herschel. .Of the results of these observations, it is of course impossible to give any general idea within the space to which we are limited in this article : for powerful testimony to the importance of the subject, and to the success with which Mr. South’s labours in this branch, of astronomy have been attended, we may refer the reader to the last number of the Amnals.. He will there find the address lately delivered by the President of the Astronomical Society, on presenting the gold medals, awarded by that body, to Mr. Herschel, the author of the memoir before us, and Prof. Struve, for their zealous and indefatigable pursuit of this subject of Double Stars. 1826.] Philosophical Transactions for 1826, Parts l.and II. 53 To these observations Mr. South has appended a synoptical view of the results’ afforded by them, and by those detailed in the former communication ; which itself occupies eighteen large and closely-printed quarto pages.” We now proceed to ‘the ca tygremeearty in the second part of the Phil. Trans. for 1826. . An Account of the Construction and Adjustment of the new Standards of Weights and Measures of the United Kingdom of Great Britain and Ireland. By Capt. Henry Kater, FRS. The labours in this interesting application of the refinements of modern’science to the arts and purposes of civil life, in which some of the most distinguished natural philosophers of the pre- sent day have, for about ten years past, been engaged, terminate, we presume, with the verifications recorded in this paper.. When we reflect on the unremitting diligence with which those labours have been prosecuted,—on the manner in which so many distinct branches of mathematical and physical research have been con- centrated, ‘as it were, and ‘directed towards the’objects to ‘be attained,—and on the final results, as well philosophical as prac- tical,of the whole inquiry, we think we may with justice congra- tulate our readers, ‘and the country at large, on'the satisfactory establishment of the long-desired uniform system of weights ‘and - measures: And we are far from considering, as appears to’ have been done ‘by some writers on the subject, that the objections lately urged, with so much accuracy of’reasoning, by Capt. Sabine, against the means at present appointed for ascertaining and recovering the standard of linear measure, tend essentially to invalidate the new system. They seem to us, on the contrary, to contribute powerfully to its support ; by showing the pendu- lum to afford the: most appropriate natural standard for the se et requiring, however, corrections and modifications itherto: unemployed. . Nor should it be forgotten, as an evidence of the soundness of the’ principles on which ‘the. system has been founded, that the experiments which indicaté the expediency of these corrections, constitute, in fact, a por- tion of the train of researches to which the means pursued for “ascertaining and establishing uniformity of weights and measures,” have given rise. They were undertaken’ by Capt, Sabine, in consequence of the discrepancies, with regard to the figure of the earth, of the results obtained, by combining the lengths of the pendulum observed by Capt. Kater at the different stations of the trigonometrical survey of Great Britain, with those observed in utio#. We would suggest, then, that the prope view to be taken of the subject is the following: That a igh degree of precision in the means of determining the natural standard, and one in all respects worthy of the existing state of science, has already been attained; but that a portion of the investigation for the ascertainment of those means, has shown a further. refinement of them to be desirable. And it may be 54 Analyses of Books. [Juny, observed, that the imperial standard-yard, which is the unit of the measures of length, and an aliquot part of which gives the means of recovering the standard of weight, from which again the measures of capacity are derived, will remain unaltered, together with all the derivations from it, whatever rectification the natural standard may be found susceptible of in future. — The legislative recognition of two denominations of weight, in retaining both the troy and the avoirdupois pound, has been mentioned as a defect in the system. But we think that the inconvenience in numerous commercial concerns, which must have been experienced, had either of them been rejected, would have much more than counterbalanced the departure from strict uniformity, (a departure, indeed, which we conceive to be rather imaginary than actual) that has ensued from the retention of both. In their determination of this and similar points, the Commis- sioners of Weights and Measures appear to have acted, and in our opinion wisely so, in the spirit of Sir G. Shuckburgh Eve- lyn’s remarks on the propriety of retaining the eommonly- received denominations of quantity. These remarks are so apposite on the present occasion, that we must be permitted to quote them; premising, however, that they contain some implied reflections on the French Systéme métrique not altogether deserved. They occur in Sir George’s * Endeavours to ascertain a Standard of Weight and Measure,” (Phil. Trans. 1798) and it will be remembered with gratitude to his memory, that in these very accurate “‘ Endeavours,” was laid the foundation of the new system. After having ascertained the length of the proposed natural standard, the pendulum, and determined the weight of any given bulk of water compared with it, Sir G. 8. preageie to deduce the proportion of these to the commonly-received weights and mea- sures of this kingdom. “It is perfectly true,” he observes, ** that if I chose to indulge in fanciful speculation, I might neg- lect these comparisons, as an unphilosophical condescension to modern convenience, or to ancient practice, and might adopt some more magnificent integer than the English pound. or fathom; such as the diameter or circumference of the world, $c, &c. and, without mueh skill in the learned languages, and with little difficulty, I might ape the barbarisms of the present day. But in truth, with much inconvenience, I see no possible good in changing the quantities, the divisions, or the names of things of such constant recurrence in common life; I should therefore humbly submit it to the good sense of the people of these kingdoms at least, to preserve, with the measures,’ the language of their forefathers. I would call a yard a yard, and a pound a pound, without any other alteration than what the precision of our own artists may obtain for us, or what the lapse of ages, or the teeth of time, may have required.” pees 1826.) Philosophical Transactions for 1826, Parts I. and II. 55 An abstract of Capt. Kater’s paper now before us, has already appeared: in the Annals for February last; but there are some particulars respecting the construction of the standards, and the adjustmentof the national copies of the imperial standard-yard rigorously identical in length with Sir G. Shuckburgh’s, scale, that demand insertionin,this place. | . Brass being peculiarly liable to decomposition in the atmo- sphere of London, the standards of weight and of measure of capacity, have been formed ofan alloy, consisting of 576 parts of copper, 59 ofitin, and 48.of brass; and this is equal in hard- ness to. hammered brass, and can be worked wath the same facility. o00 1 i jonk 1461 The construction of the standards of measure of capacity, and of the weights, is thus described: __. Oda: Op) oo“ In order to, avoid any innovation but such as, might be absolutely’ necessary, it was deemed expedient im construct- ing the bushel, to adhere as nearly as possible to the form of that known by the appellation of the Winchester bushel. It was therefore directed to be made cylindrical, the interior dia- meter being about 184 inches, the exterior 194 inches, and the depth about 81 inches, and intended to contain eighty pounds avoirdupois of distilled water. In order to give the bushel addi- tional strength, it was cast with two projecting hoops, one to which the bottom was serewed,.and another at the distance of about half an inch from the top. vere , . Considerable difficulties arose in casting the bushel; out of twelve, only five proved sound enough for use ; but by vary- ing the process, they were at.length procured sufficiently per- fect. Much credit.is due,to Mr. Keir, the engineer employed by Mr, Bate in turning the bushels, for the beauty and perfec- tion of his work. | as 134k, iti oMaleddanrte »o The form of the gallon measure occupied much of my attention. It was necessary that it should be such as to enable me to determine the weight of distilled water. it should con- tain with the least liability to error. The conical form was there- fore adopted ;. the mouth being made. cylindrical, and, one and a half inch diameter: the top was ground perfectly flat, and the edge so rounded off, that the contents, might be poured from it.imto,any other vessel without running down the side. . The. cone was placed in a cylinder about four inches high, in which handles were formed, and which served at. the Same time to protect the gallon from injury, and to prevent any change of temperature which might arise from handling. The:quart.and the pint measures were of the same form, ona sitiallet:Aeale jon eink fossa. ou l me . “The weights were of brass, and nearly of a spherical form, but flattened. at the bottom. Into the top was, screwed a button; beneath which. a small cavity was left to receive ee: UL /. | Analyses of Books.- . . 4 Juny, such minute pieces of wire as might be found. requisite. to make up the standard-weight, This button served also to lift the eight by means of a strong wooden fork.” ; Four ibidnid yatta were made by Mr. Dollond, of brass, one inch square; having firmly screwed to their extremities rectangular pieces of steel of the same width as the bar, and rojecting above its surface. The distance between the interior fice of the steel terminations. was intended to be equal ‘to the length of the imperial standard-yard; and one of them, since deposited at the Exchequer, Westminster, Capt. Kater found to be perfectly correct ; whilst one of the. others was only 00038 of an inch too short, and of the remaining two, one was "00021 of an inch too long, and the other the same minute quantity too short. | ; | The following section of the paper is so important, and fur- nishes an example of extreme precision in these adjustments so truly philosophical and interesting, that we must give it entire. “ Adjustment of the Standard-Yards with Gold Points, “The standard yards last described are intended merely for the purpose of sizing those employed in commerce, and the trifling differences above stated .may be utterly disregarded ; but the Commissioners of Weights and Measures thought it desirable, that accurate copies of the imperial standard-yard should be made, to be carefully preserved and transmitted to posterity, solely for the paapenerad being referred to upon extra- ordinary occasions, or upon questions important to science. “ The difficulty of transferring a given distance from one scale to another, is well known to all- who are acquainted with the subject; the operation is .one of considerable delicacy ; and notwithstanding every precaution is seldom absolutely free from error. But a national standard should be accurately that which it professes to be. It is not enough to determine its error, as the record of this may in process of time be lost; it therefore became necessary to devise a method by which any perceptible error in those standards which are the foundation of all: the others, might ultimately be annihilated. it hh RR “The four standard-yards which Iam about to describe are. of brass, an inch and a quarter wide, and half an inch thick. This thickness is the same as that of Sir G. Shuckburgh’s scale, and was chosen in order that both might be affected with equal readiness by any change of temperature ; for as the imperial standard-yard of 1760 is one inch square, | thought it preferable to adjust the new standards. by means of Sir G. Shuckburgh’s scale, which, as I have before remarked, does not sensibly differ from it. Subst’ «A disk of gold being let into the surface near one extremity, a hole was drilled through the bar at the distance of thirty-six 1826.] Philosophical Transactions for 1826, Parts I.and II. $7 inches from the centre of the disk, and being made slightly conical, a plug of brass was Spies: in the hole so as to fit it perfectly. A gold disk was let into the top of the plug, and reduced to a level with the surface of the scale. The other end of the plug projected beneath the scale, and had a small hole through it to admit a wire, by means of which it might be turned round.» A very fine deep dot was then made by Mr. Dollond upon each of the gold disks, as nearly as it could be done at the - distance of thirty-six inches from each other, the dot upon the moveable disk not being exactly in its centre. “‘ Before the plug was ground in its place a small hole was drilled through the side of the scale into the conical aperture. ‘“‘ The microscopical apparatus employed on the present occa- sion, has been described in the paper upon the comparison of various British standards of linear measure, before quoted. ‘The cross-wires of the microscopes’ being brought respec- tively over zero, and thirty-six inches upon Sir G. Shuckburgh’s scale, the apparatus was transferred to the new standard, and the intersection of the cross-wires of one of the microscopes placed upon the centre of the fixed dot. The moveable dot was then brought, by turning the brass plug, to the intersection of the cross-wires of the other microscope.’ — | ‘“‘ The. distance of the dots was repeatedly compared with Sir G. Shuckburgh’s standard upon different days, in order to ascer- tain that no perceptible error remained. A drill was passed through the hole in the side of the scale, and the brass plug carefully pierced through ; a pin was then driven into the plug so as to render any change of position impossible, and the pro- jecting part of the plus was cut off. “‘ The standards being thus finished, they were again compared with Sir G. Shuckburgh’s scale, and it was with surprise and disappointment that | found the whole of them apparently too short. They had been adjusted upon a board of mahogany care- fully planed, and the table upon which they were now placed was so flat-as to-occasion little alteration in a spirit-level passed along it.. The error of the standards was, however, far too con- siderable to be attributed to any curvature which on this occasion could take place, and it was not until after several days that I discovered the cause of this perplexing circumstance. [ found that by placing a card, the thickness of which was accurately one-fiftieth: of an inch, under the middle of the standard, the distance of the dots was much increased, and by placing a card of the same thickness under each of the extremities, and with- drawing that which was under: the centre, the distance of the dots was ‘considerably diminished. The total difference amounted to no less than :0016 of an inch, whilst the double of the error which would have arisen from mere curvature under 58 . Analyses of Books. 9...) [Wituy, similar circumstances, would not have been one ten-thousandth of an inch. | rid $O-7%pD , bai frer “ The cause was now evident, by elevating the middle of the standard, the under surface was shortened, and the upper sur- face extended ; and on the contrary, when the extremities were elevated, the upper surface was compressed, and the lower surface lengthened, the quantity of the effect evidently depend- ing upon the thickness of the bar. i : Be ie “Having thus assured myself of the source of the error, a method of obviating it soon presented itself. As the upper and under surfaces of the bar are in different states, the one being compressed and the other extended, there must be an interme- diate plane which suffers neither extension nor compression, and this plane must be nearly midway between the two surfaces. I — therefore caused Mr. Dollond to reduce the thickness of the bar for the distance of an inch and three quarters from its extremi- ties to one-half; the gold disks and plugs were then inserted as before, and the adjustment completed in the manner which has been described. The plugs being secured, and the projecting arts removed, the standards were repeatedly compared with Rit G. Shuckburgh’s scale (the standard being placed upon the scale) when no perceptible difference could be detected. Pieces of card were now placed under the standard as before, without occasioning any appreciable alteration ; and I had thus experi- mental proof of the. perfect efficiency of the remedy I had employed. | | “T have been thus particular in detailing the difficulties I experienced, because they exhibit a source of very considerable error which may arise from the thickness of a standard-scale, and which, I believe, has never before been suspected... _ It may be here not unnecessary to remark, that on every occasion on which [ have used Sir G. Shuekburgh’s scale, it has fortunately been placed not only upon the same table, but upon the same part of it.” 7 The various standards described in this paper, with the excep- tion of the yards with steel terminations, are not intended for common use, but to be carefully preserved for reference upon extraordinary occasions. In addition to them, other weights and measures of capacity were made with great care by Mr. Bate. The following is a list of the whole; the numbers of the stand- ards corresponding with those inscribed.on them by Capt. Kater, during the adjustment, as detailed in the memoir. . “ Standards deposited at the Exchequer, Westminster, 1 Imperial standard-yard with gold points. 1 Standard-yard with steel terminations, No. 1. 1 Imperial troy pound, No. 5. . 1826.] Philosophical Transactions for 1826, Parts I. and II. 59 — 1 Avoitdupois pound, No. 1. 1 Avoirdupois pound, No. 5 (in a box with smaller weights.) 1 Weight of imperial gallon of water, No. 1. 1 Imperial gallon measure, No.3. 1 Bushel, No. 8. 1 Quart, No. 4. } Pint. A copy of the imperial gallon. 2 quart, and wilt pint. 1 Bushel. 1 Haltbishe. for common use. 1 Peck. 1 Gallon. =) 1 Half-gallon. 1 Quart. | 1 Pint. > cylindrical, for common use. 1 Half-pint. . 1 Gill. 1 Half-gill, | | 1 Set of avoirdupois weights, from 56 lbs. to half a drachm. 1 Set of counterpoises for the above set of weights. — 1 Set of troy weights, from one pound to one grain, with counterpoises.”’ « Standards deposited at Guildhall, London. 1 Imperial standard-yard with gold points. 1 Standard-yard with steel terminations, No. 4. 1 Imperial troy pound, No. 1. 1 Avoirdupois pound, No. 2. 1 Weight of imperial gallon of water, No.3. | Imperial gallon measure, No. 5. 1 Bushel, No. 4. ! i 1 Quart. 1 Pint. 1 Set of avoirdupois weights, from 56 lbs. to half a drachm.” At Edinburgh and Dublin sets of standards have been depo-_ sited; corresponding with the set at Guildhall. _ As an Appendix to this paper, a table is given of the correc- tion on account of temperature to be applied to the contents of the gallon; and in a postscript Capt. Kater awards to Professor Bohnenberger, the honour of having fikst proposed to determine the length of the seconds pendulum by means of the convertible at in an astronomical work, published at Tubingen in i II. Deseription of animproved Hygrometer. By Mr, Thomas Jones : communicated by Capt. Kater. _ This brief communication 1s as follows : 60... _ Analyses of Books.. (Jory, “The attention of the scientific world has been lately so much occupied in experiments on atmospheric phenomena, that it is hoped any simplification or improvement in the instruments rae a tg for that po may not be me ’ “ The principle of the Sygrencvet which I am about to describe, 1s that of enabling the observer, readily and accurately, to ascertain by direct and simple means, the degree of tempera- ture at which the moisture of the atmosphere is condensed, and the instant at which that operation commences. — *‘ The hygrometer is composed of a mercurial thermometer, the graduated scale of which is about four inches and a half long; at the lower part of the scale the glass tube is bent to form a right angle, at the end of which the bulb of the thermometer rises parallel to the scale, and about one inch from it; the bulb is about one inch long, and of a cylindrical form, with a black convex top, the diameter of which is a little more than that of the cylindrical part, which is covered with silk. The scale is attached to a piece of cylindrical wire, three inches long, and turns upon a joint screw passing into its edge, the other end of which wire being placed ina tubular foot fixed to the inside of one end of the case, forms a stand for the instrument. The case contains a small bottle for ether. - | i “The thermometer thus constructed will give both the tem- perature of the air and that of the dew-point, which last is effeeted by placing the mouth of the bottle containing the ether, in contact with the upper part of the covered surface of the bulb, when, by gently inclining the bottle, the ether will flow down- wards without wetting the top of the bulb, which will almost immediately become dull by the deposition of moisture on its surface ; i the observed temperature may be taken and the difference ascertained, ° Wf “Should it be objected against the principle of the instrument here proposed, that the indications do not exhibit the true tem- perature of the upper surface of the bulb, on which the deposi- tion of dew takes place, but that of the lower part, to which the ether is applied; it may be answered that by inclining the whole instrument so as to render the axis of the bulb horizontal, and establish thereby a free circulation of the mercury in every ports this objection may be obviated ; but on repeated trials I ave not found this to produce any ditference in the results. “ | ought also perhaps to mention that an instrument somewhat similar in principle has been used in Vienna, and was mentioned by Prof. Baumgarten of that capital to a friend, who communi- cated the fact to myself.” an A A representation of this hygrometer is given in an accompany- ing plate. gut .W.B, (To be continued.) 1826. : Proceedings of Philosophical Societies. 6k Articis XII. Proceedings of Philosophical Societies. ROYAL SOCIETY. May 25.—The Right Hon. Sturges Bourne, and Dr. A. P. Wilson Philip, were admitted Fellows of the Society ; and the reading. of Mr. Osler’s paper, On the Burrowing and Bormg Marine Animals, was concluded. } tet. In this paper, the operations and mechanism of burrowing and boring, as practised by various marine animals, belongin to the classes. Mollusca and Annelides, are first sAtanpubyidedcsibeet Facts are then adduced, tending strongly to prove, that the Lithophagi effect their perforations, not by mechanical means, but by a solvent fluid, which, however, being secreted only when required for use by the animal, the author has not been able to detect by chemical tests. These animals perforate cal- careous stone, and shell, but their prowrere is stopped by silice- ous or argillaceous matter, on which they are unable to act ; thus a thin layer of clay occurring in. a rock which they are: perforat- ing, forms to them an impassable obstacle. Another important fact related in this paper, having the same bearing, is as follows : —The Saaicave often exert their boring powers on the shells of contiguous individuals of their own species.; and so long as they have not penetrated through them, no notice is taken of it by the animals attacked ;. but when the perforation is complete, or very neatly so, the aperture is immediately filled up, not with shell, but with a yellow animal-substance, insoluble even in the mineral acids. - | June 1.—The following papers were read :— | _ An Account. of some Experiments relative to the Passage of Radiant Heat through Glass Screens; by the Rey. Baden Powell, MA.FRS. — he ab The object of this paper was to examine a question arising from De la Roche’s experiments, as to.a particular case in which that experimenter supposed there must be a direct transmission of simple radiant heat through glass. This case is that of a second glass screen interposed between a first and the thermo- meter, when M. De la Roche found the additional diminution much less in proportion, than that occasioned by the first screen on the total effect. He hence supposed the heat to have acquired a property analogous to polarization, by which it was enabled to penetrate the second screen without loss. . i The experiments here detailed were designed to examine, first, whether this effect could be verified; and, secondly, whether, if so, it could be accounted for without introducing * 69 Proceedings of Philosophical Societies. [Juny, any new or peculiar property of heat. The results show that the fact is ar 8 | verified, and at the same time the peculiar explanation rendered unnecessaty ; as from observing the tem- peratures acquired by the screens, it ty ead that the effect was exactly such as would be accounted for from the simple circumstance of a secondary radiation from the screen. In the sequel of the paper the recent experiments of Mr. Ritchie were adverted to, who has maintained that simple heat radiates directly through very thin glass when transparent, but not when opaque. This result was tried by a different method from Mr. R.’s, and no difference was found to be occasioned by the transparency of such a screen, : . Thus two apparent exceptions to the general law “ that simple heat cannot permeate glass,” are done away. An Account of a Telescope having only one Reflector, and of easy Management in observing ; by the Rev. Abram Robertson, DD. FRS. . id Account of some Experiments on the Laws of Electrical Accumulations on coated Surfaces; On the Construction and Use of a Magnetic Balance ; and On the Electrical Conducting Power of various Metallic Substances ; all by W. S. Harris, Esq. : communicated by the President. ie June 8.—The Bakerian Lecture; On the Relations of Electri- cal and Chemical Changes; by Sir H. Davy, Bart. PRS. was read. A The experimental ire, (ae and results brought forward in this Lecture, are prefaced by a historical sketch of the origin and progress of electrochemical science, with a view of correet- ing the erroneous statements that have appeared on the subject, The origin of this branch of knowledge is stated to be the dis- covery of the decomposition of water by the voltaic pile, by Messrs. Nicholson and Carlisle in 1800. This was followed by the experiments of Cruickshank and of Dr. Henry, and by several papers by the author himself, the chief contents of which are stated, and in which the appearances of acids, ahd oxygen, at the positive, and of alkalies, sulphur, and the metals, at the negative pole, were described. he experiments of Hisinger and Berzelius, m 1804, are laced next in order, which establish similar results; and in 806, on the occasion of the agitation of the question respecting the production of muriatic acid and fixed alkali from pure water, the author presented to the Royal Society his Bakerian Lecture on the Chemical Agencies of Tdoetricity, in which he drew the general conclusion that the combinations and decompositions by: electricity, were referrible to the law of electrical attractions and ipidlaliindvore theory in which, he observes, he has hitherto found nothing to alter, and which, after a lapse of 20 * woe has continued, as it was in the beginning, the guide and foundation 1826.} oo Royal Society. vf 63 of all his researches. The instruments used in the experiments of the present paper for detecting and estimating electric cur- rents of low intensity, were constructed on the principles of the multiplier of Prof. Schweigger, and the galvanometer of Prof. Cumming. For determining weak electricities of tension, Volta’s condenser, connected with Bennet’s electrometer, or with one consisting of a silk filament rendered conducting by charcoal dust, was employed. Muchdependence was, however, never placed on these instruments, unless their indications were, otherwise confirmed. } | . The author now proceeds to the experimental inquiries: which form the chief object of his lecture, and to the general views of electrochemical agency to which they appear to lead. And first, he considers the electrical and chemical effects exhi- bited ‘by combinations of one metal and one fluid: the nature of these effects is best explained by an example. When two pieces of polished copper connected with one extremity of the wire of the multiplier, are plunged into a solution:of an alkaline hydrosulphuret, if introduced at the same instant, there is no action ; but if in succession, a sensible interval bemg allowed to’ elapse, there is a distinct or even a violent electrical effect, and the piece of metal first introduced is negative with respect to the other: this effect depends on the formation of a coat of sulphuret of copper on the plate first introduced, while it is negative with respect to metallic copper. Hence the combina~ tion is in strictness one of three elements; copper, sulphuret of copper, and the solution. In like manner, protoxide of copper is negative with respect to pure copper, and to the sulphuret. The production of electrical currents by single metals and single fluids occurs generally whenever new products adhering to the metallic surfaces are produced ; and if the same products be applied artificially, the effects are the same, as if the adhesion had been caused by the natural action of the fluid on the metal. ‘The chemical changes produced in the fluid by the ternary com- binations thus formed are, in all cases, such as tend to restore the deranged equilibrium, hydrogen passing to the negative side, and oxygen to the positive, until the oxides are revived. The case of two imperfect and one perfect conductor is next considered, as two fluids and a metal or charcoal. Here the. author controverts an opinion advanced on high authority, respecting the alleged development of electricity on the combi- nation of acids and alkalies, which he refers to the contact of metals with these agents, to change of temperature, evaporation, &¢. and never to the mere union of these bodies : several expe- riments are adduced in support of this opinion. When platinum is brought into contact with an acid, the pole touching the acid is negative, the opposite pole positive, and 64 Proceedings of Philosophical Societies. Jury, . vice vers Where it touches an alkali; and the same is the case with rhodium, iridium, and gold, the effect being greater as the action of the acid on the metal is greater. From this it follows, that when a metal is in contact with an acid or alkali in one cup, and water or a neutro-saline solution in another, on completing the circuit, the contact of the metal with the acid or alkali will determine the character of the pole in contact with it, and that in contact with the other fluid will of course be of the opposite name, and this result is confirmed by experiment. In such combinations, the chemical changes are such as might be expected; oxygen and the acids tending to circulate towards the negative surface, and hydrogen and the alkalies towards the positive. _ In combinations consisting of two perfect conductors and one fluid, the order in which the metals exhibit their electricities is connected with their oxidability, the more oxidable metal being positive with respect to all below it. It is not, however, any inherent quality in the metals which determines this effect, but their fitness for chemical action; for if the state of aggregation be altered, and the cohesive force, which always acts as an antagonist force to chemical changes, be weakened, the posi- tive energy is exalted in proportion: thus the amalgams of the positive metals are positive with respect to the pure metals of which they are amalgams. In general, the electricities deve- loped by metallic contact are too strong to be subverted by an opposite action with the fluids with which both are in contact. . Such, however, is sometimes the case; and in all instances, the influence of the fluid is perceptible. — Lin: tae The author next considers the accunmulation of electricity, and. the chemical changes it produces in voltaic arrangements, According to Volta’s view of the action of the pile, the metals were regarded as the only agents, and the chemical changes arising in the fluids as mere results not essential to the develape; ment of the electricity. This view, however, may be regarded as altogether disproved by an experiment here described, in which, when two glasses, filled with solution of nitrate of potash, in which were plunged respectively zinc and platinum connected by the multiplier, were connected by substances capable of conducting electricity, but not of propagating chemical action, such as unoxidable metals, the circulation of the current was altogether destroyed. | ae Since the chemical changes always tend to restore the equi- librium, destroyed by the contact of the metals, in the fluids of a pile, it is evident that the relation between the fluids them- selves and the surfaces with which they are in, contact, will be altered by a continuance of the action of the pile. Hence it is easy to perceive the possibility of a re-action taking place when thé circuit is broken, or the disposition of the parts ofa pile is . MBLC}. © its Royal Society... : 65 changed, or one or more parts ofa compound circuit abstracted. Many curious phenomena, of which hitherto no explanation has been offered, may be’ explained by this view of’ the subject; suchas the secondary piles of M. Ritter—the supposed polariza- tion of electricity, concluded by M. de Ja Rive from his experi- ments .on the interposition of metallic plates in the fluids of a. pile,—and the continuance of electro-motive action of detached _ portions of a circuit, after the destruction of the circuit itself. This re-action is illustrated in the present paper by an experiment, in which a circuit primarily inactive, consisting of six ares of platinum in vessels filled with solution of nitre, was made part of a battery consisting of 50 pairs of plates of a combination primarily active. After continuing the circuit some time, it was broken, and the platinum arcs, detached and formed into a circuit, were found to possess independent action, contrary to that of the pile, which had thus rendered them re-active. _ This singular consequence is pursued yet further in another experiment here stated, in which detached portions of a battery of 50 plates which had been some time in action, were examined as separate piles, after breaking up the combination. When they had been placed conformabdly in the original battery, their independent action was found to be very much weakened by the re-action thus produced, which in this case opposed their natural effect; whereas, when unconformably placed in the original battery, their action when detached was found exalted to-three or four times its natural intensity. sri odes The author next proceeds to point out some general observa- tions and practical applications which suggest themselves on a view of the foregoing results. The chemical changes in a con- ducting liquid, he first shows, take place only in the immediate vicinity of the immersed poles, the rest of the liquid affording only a tranquil passage to the electricity. This leads him to consider the motions produced in mercury when interposed in the circuit under an electrified fluid, which he regards as arising from the two electricities, acting as transporters of ponderable matters which assume their own peculiar characters when they reach ‘their point of rest. The lecture concludes with -some suggestions as to the use of the multiplier to obtain exact nume- rical measures of the electro-dynamic.relations of chemical elements ; and with some applications of the preceding results to the useful arts, especially in the preservation of the copper on ships, and of the iron boilers of steam-engines. - | A paper was also read, On the Discordances between the Sun’s observed and computed Right Ascensions as determined —_ Blackman-street Observatory ; by James South, Esq. June 15.—Sir. G. Nayler, Knt. Garter King at Arms, was New Series, vou. Xu. r 66 Proceedings of Philosophical Societies. [Juny, admitted a Fellow of the Society; and the following papets were read, or their reception announced: 11> eB) Observations on a Case of Restoration of Vision: by James Wardrop, Esq : communicated by the President. In this paper is described the operation of forming an artifi- cial pupil, by which sight was given to one eye of a lady, forty- six years of age, who had been blind from infancy, The globe of the other eye was collapsed. The phenomena ensuing, in | the gradual acquisition of the various discriminations of sight, sarees with those detailed in similar cases by Cheselden, and others. 0 | On the Existence of a Limit to Vaporization; by M. Faraday, Esq. FRS. , | | 7 Hh Some notice of the arguments. brought forward in this com- munication, and of the facts on which they are founded, may be seen in our report of the Proceedings of the Royal Institution, at p. 390 of the last volume of the Annals.s ) n Electric and Magnetic Rotations; by Charles Babbage, Esq. MA, FRS. dbed doide aisle 0 On the Progressive Compression of Water by High Degrees of Force, with some Trials of its Effects on other Pluide: b caid> Perkins, Esq.: communicated by W.H. Wollaston, MD, VPRS, In this paper Mr. Perkins first describes in detail, with the aid of illustrative drawings, the apparatus for experiments on the compression of water, suggested by him in his paper onthe subject published in the Philosophical Transactions for. 1820, He then briefly relates some of the experiments performed by its means, referring to a plate annexed representing by a curve, the law of condensation under. pressures of from 10 to 1000 atmo- spheres, and also to a table showing the results numerically. In one experiment, the water was compressed one-twelfth of its volume, by a pressure of 2000 cccimblerea, Some experiments on other liquids, and:on aériform fluids, ane also adverted to: among the former, acetic acid was crystallized, and among the latter atmospheric, air and carburetted hydrogen gas were lique- fied, by the same apparatus. . On the Figure of the Earth; by G. B. Airy, Esq. MA. : com- municated by the President. | | Observations for determining the Amount of Atmospheric Refraction at Port Bowen; by Capt. W. E. Parry, FRS.; Lieut. H, Foster, FRS.; and Lieut, Ross. On the Crystallization of Uric Acid ; by Sir Everard Home; Bart. VPRS. Microscopical Observations. on the Muscular Fibre of the Elephant; by Herbert Mayo, Esq.: in a letter to Sir E. Home. e reception of papers, on some phenomena in magnetism, and on a shell exploding by percussion, by Mr. Christie and 1826.3 as Royal Institution. 67 Col, Millar respectively, was also announced ; and the Society then adjourned over the long vacation, to meet again on Thurs- day; the 16th of November next. : -/ PROCEEDINGS OF THE ROYAL INSTITUTION OF GREAT BRITAIN; AT THE FRIDAY-EVENING MEETINGS. ~ May 26.—Dr. Harwood read the second part of his paper on the Elephant genus, his observations being at this time confined to the natural history of the African species, with an account, however, of peculiarities in the structure and in the senses of Elephants generally. The communication was illustrated by a very numerous set of drawings, and specimens, a great number of them from the magnificent collection of Mr. Brookes. _ _ Several models of ancient buildings were placed on the library tables by Mr. West, the general aspect and appearance of decay being given them by a peculiar method of colouring the sub- stance, as well as the form of the building. : : . June 2.—Mr. 8. Solly completed his observations on. the porphyry of Christiania. : ) Arifle, of a newconstruction, was laid upon the table, remark- able for its lightness. The length of the barrel was 24 inches, and the weight of the whole only 41 lbs. It was constructed under the direction of Mr, Leigh. : _ June 9.—The subject of the evening was the tunnel at Rother- hithe.. Its history was given by Mr, Faraday from the lecture- table for Mr, Brunel, and illustrated by numerous fine drawings, models, and apparatus. The undertaking was followed from its commencement to the present time; the beautiful contrivances of Mr, Brunel explained, the weights and measurements given, and the present condition of the work stated. Ithas been con- ducted to its present state with the greatest success, and from the experience obtained, there is every reason to anticipate that success will attend it to its conclusion. a ; The meetings of the members were then adjourned till next season. 3 GEOLOGICAL SOCIETY. May 19.—A paper, éntitled Notes on the Geological Position of some of the Rocks of the NE. of Ireland, by Lieut. Port- lock, Roy. Eng. FGS:, was read. In this paper, the author alludes to the communications on the same subject by Dr. Berger, Dr. Buckland, and the Rev. W.D. Conybeare, published inthe Geological Transactions; and, after some remarks on thé granite and mica-slate rocks of the Mourne Mountains, the Carlingford, and another groupe occu-. pying a large’portion of the north of Derry, cthe barotnetrical ! | F2 | 63. Proceedings of Philosophical ‘Societies. [Jury,. admeasurement of which is given,) he proceeds to notice the phe- nomena of the basaltic range, and to observe the connection of the indurated chalk with the basalt ; beginning: at: the: south near Belfast, where it is underlying, and almost in contact with the basalt of Mount Divis, tracing: it at various points north- wards to Ben Evanagh, and hich up in Benbradda,. and de- scribing the gypsiferous marle, having the same dip (30° NW.) and line of direction as the chalk ; next to which, and between it and the basalt, there is generally a thin stratum of ochre. To the south of the line of chalk, and resting on the Dromore porphyry, a highly indurated argillaceo-siliceous schist is found, assing by various shades into a claystone porphyry, being, sgsites in its simple state harder than the basis of the por- ry. ‘ ‘Re author concludes by giving his opinion that the density and crystallized structure of basalt are not affected by the amount. of pressure, and stating that he has not been able to make out any decided aed of the stratification of that rock. June 2.—A ‘paper, entitled, On the Freshwater Strata of Hordwell, Beacon, and Barton Cliffs, Hants, by C. Lyell, Esq. FGS., was read. “The author, after confirming Mr. Webster,s discovery of a distinct freshwater formation on the Hampshire coast, cor- responding with the lower freshwater formation in the Isle of Wight, states, that in consequence of the suspicions entertained of the possible occurrence of the upper marine formation in some of the upper strata of Hordwell cliffs, he has examined the beds ; a minute detail of which, in their order of superpo- sition, together with the organic remains peculiar to each, is given. Bituminized wood, seeds, and capsules of plants (among them Carpolithes thalictroides, Brongnt.), with freshwater shells, abound therein ; and, in a bed of calcareous marle, sometimes slightly indurated, from 6 to 8 inches thick, and consisting of an aggregate of Planorbes and Lymnee, an abundance of Gy- rogonites (Chara Medicaginula) was found. In the bed imme- diately above were discovered the scale of. a Tortoise, and the teeth of a Saurian, probably a Crocodile.—From the presence of two species of Serpula the author supposes that this series of strata might have been formed in an estuary. The shells, from the occurrence of which the existence of marine strata in Hord- well cliff had been before inferred, prove to be species of Pota- mides, a freshwater genus ; and the beds which lie above these are exclusively freshwater. | Of the new organic remains, the valves of a Cypris, smaller than that found in the Weald clay, but in as great proportion, are characterized as the most interesting, and a small Ancylus is 1826.) Scientific Notices—Chemistry. 69 “also noted ;*whilst the presence of ¢yrogonites and Carpolithes thalictroides is quoted as completing the ‘resemblance of the ‘Hordwell strata to those of the Paris basin. © The author further observes, that the freshwater strata do not erop out in Beacon Cliff, as had been supposed, but are con- tinued for about a quarter -of a mile or more in Barton Cliff, ‘interposed between ‘the diluvium and white sand that cover the Londen ‘clay : and, ‘scarcely hesitating to refer the white. sili- ‘cious ‘sand (which rises in, Beacon Cliff, and is continued through Barton’ as ‘far as the High Cliff, near Muddiford), and, ‘consequently, the analogous bed resting on the London clay in Alum Bay, to the freshwater series, he concludes, from the incli- ‘nation of the strata ‘in the latter place, that the freshwater formations suffered, though in:a‘less degree, the disturbance to which the vertical strata of the Isle of Wight were subjected. June 16.—A paper was read, entitled, Notes on the Geolo- ‘gical Structure of Cader Idris; by Arthur Aikin, Esq. FGS. ; ‘an abstract of which will appear in our next number. E..W.B_ | ArticLte XIII. “SCIENTIFIC ‘NOTICES. CHEMISTRY. 1. On the Absorption of Gases by Liquids. By T. Graham, MA. ¥ - (Communicated by.the Author.) 1. Liguips-are in general miscible with one another, in all “proportions as water and alcohol, or in a limited degree as ether -and water; ether agitated with: water taking up one-tenth of its _ weight of that liquid. ' 2. Frequently the mixing of liquids exhibits the closeness of ‘chemical union, among other points, in the manner in which ‘the volatility of the compound liquid is affected. Thus the ‘vapour from pure alcohol at 170° Bahr. supports a column of ~mercury of 30 inches, but by mixing the alcohol with a quantity -of water, we impair the volatility of the alcohol; and we ma ‘form mixtures which require a temperature of upwards of 200°, ‘to produce vapour capable of supporting such a column. In the _. Same way portions of water are retained with so great force ‘by ‘sulphuric acid, as to require, in order to drive them off, a degree -of *heat greatly higher than‘ the ‘boiling point of water. ‘From these, and other instances of this affinity, we learn, that in a mixture of a volatile and more fixed liquid, ‘the tendency of the 70 Scientific Notices—Chemisiry. [Juny, more volatile ingredient to pass into vapour may be checked in a considerable degree by its connexion with the other liquid... That many reputed gases, at a low temperature, or under great pressure, assume the liquid form, has been demonstrated y Mr, Faraday.* The researches of that ingenious chemist on gaseous liquefaction, strongly impress the doctrine, that in the physical states of gas, liquid and solid, there is nothing of abso- ute permanency, and that any body may assume consecutively all these forms, Hence it follows that those bodies, which at the temperature of the atmosphere, we experience to be gases, may be considered without impropriety as volatilized liquids ; and we may predicate of such bodies, the common properties of liquids, Of these properties, two have been mentioned, which alone will be applied to the elucidation of the phenomena of absorption, da + oir usa iat It is then assumed that. the gases if liquefied (by pressure or any other means), would in general) mix im some proportion or other, with such ordinary and reputed liquids as we had itin our power to present to them; and that they would be retained in part by these liquids, through the agency of the mutual attrac- tion evinced in liquid mixture, even although the pressure under which the union took place were considerably reduced, and the temperature raised. In this way there might resulta mixture of a liquefied gas and a common liquid in reduced proportions, at the ordinary atmospheric pressure and temperature. But it is not necessary to suppose that the gaseous bodies, whose absorption by liquids it is bic: Honan explain, be pre- sented in a liquefied state. Analogy will lead us to expect that the mere injection into our absorbing liquids, of such gases in their elastic state, will occasion their liquefaction, and conse- quently bring into play the.affinities of liquids, and the conco- tmitant diminution of volatility, on which the explanation. is founded. pity 7 Thus : sulphuric acid, concentrated as much as it can be, boils at about 620°. Leta quantity of sulphuric acid so concentrated be heated to 600°, and kept at that temperature, and let the steam of water previously raised to the same temperature, be conducted into it. We would predict, without the least hesita- tion, as the result, the detention and abecumtion of the steam, notwithstanding its high elasticity, until the boiling point ofthe — acid was reduced by the dilution to 600°. Here then we have an instance of the absorption of a gaseous body (steam at 600°), by a liquid at the same temperature; yet in order to liquefy the gaseous. body absorbed, in the ordinary way, it would be neces- * Philosophical ‘Pransactions, 1823, 0, i) xisrE 1826.) Scientific Notices—Chemistry. 71 sary to cool it down through the long space of nearly 400°, or to 212° Fahr. Such a reduction below the degree of temperature at which the absorption took place, would be productive, in all probability, of liquefaction in the case of the most refractory of the gases. Now a composition of sulphuric acid and water, the same in every respect, might be obtained more directly by sim- ply mixing ‘together’ the ingredients, both being in the liquid state. This case of the absorption of a gaseous body by a liquid is, therefore, dependent upon the affinity which occasions the miscibility of liquids, and is, in fact, an instance of the mix- ture of two liquids. Many similar illustrations might be adduced. if required. | We are, therefore, authorized in concluding that gases may owe their absorption by liquids,—to their capability of being liquefied, and to the affinities of liquids (apparent in their misci- bility), to which they become in this way exposed. ‘These pro- perties may, therefore, be considered as the proximate or immediate causes of the absorbability of the gases. Upon this supposition, solutions of gases in liquids are mixtures of a more volatile with a less volatile liquid’; and to them may be extended the laws which hold in such mixtures. Several circumstances are favourable to this view of the absorption of gases. | ; 1. The cause assigned is one which we know to exist, and to be in _ operation. It is no suppositious cause of the existence of which we can adduce no other evidence, than its conveniency in ex- plaining certain phenomena. We possess evidence that almost all the gases may be condensed into liquids. They are, therefore, necessarily under the influence of those causes which we have supposed to oceasion gaseous absorbability. Thus: Mr. Fara- day condensed sulphurous acid gas into a liquid, and found that its vapour possessed an elasticity which was balanced by the weight of about 2° atmospheres at 45° Fahrenheit. Here then is a liquid, which, from the frequency of the intermisci- bility of liquids, might be expected to possess the property of. mixing so intimately with certain of our reputed liquids, as to admit of being detained by them in considerable quantity at the ordinary pressure and temperature. And, accordingly, sul- — phurous acid is absorbed and detained in large proportions by sulphuric acid and by alcohol, and in a considerable measure ‘by water. ; 2. It is a coincidence which appears more than accidental, that the gases which yielded to Mr. Faraday are, generally speaking, of easy absorbability. This will appear from the following table of the gases which were liquefied by that expe- rimenter, of the pressure of their vapours in atmospheres, and of the amount‘of their absorption by water and alcohol at 60°, 72 Scientific Notices—Chemistry. (Jury, ‘according to the experiments of Thomson; Henry, Dalton, and Saussure. Pressure of | 1 vol. water |1 vol. alcohol Gases liquefied? vapours in at-| absorbs in | absorbs in mospheres. | vols, at 60°, | vols, at 60° Ammoniacal pe eeeeebeeeecess 6°5 at 50° 780 _ Sulphurous acid,.......0..+.-}| 2 at 45 43°78 11577 Muriatic acid ,........ eeete er AO at 50 516 % aren . Cyanogen. ... ...- pasevaeese 3°T at 45 45 28 : orine ee eeeeecsoees ‘e@eeeeed 4 at 60 2 aed ‘Sulphuretted hydrogen........ 17 at 50 = 1 6:06. Carbonic acid’... .cccccccceces 36 at 32 Ba 1-86 Nitrous oxide... .. ey Bits eeeee| 50 at 45 — 1 153 Euchloringe...os...5.6e0ee ds. —- ; 8 — With the exception of fluosilicic and fluoboric gases, all the gases absorbed in considerable mnt by water, are contained in the foregoing table. While the other gases, such as oxygen, hydrogen, &c. which are condensed into liquids with great diffi- culty, are absorbed by water in very minute quantities indeed. This, however, is more than the theory requires. tc 3. Mr. Faraday was enabled to give approximations to the ‘specific gravities of some of the liquids into which the gases were reduced. Now it would be an objection to the hypothesis, if there were an excessive discordance between the specific vities obtained by Mr. Faraday, and the ‘specific -gravities which these liquids maintain.in mixture, or when in solution with water, &c. For although the specific weight of a mixture of two liquids is rarely the mean of the weights of the liquids, et in general the variation from the mean -is not excessive. here. exists, howeyer, no such discordance. Indeed, a +com- parison of these specific weights, which I have made, -re- yoarkably confirms the theory. | In addition to these facts, this hypothesis has in its favour all those circumstances which are thought to recommend the chemical theory of the absorption of gases, so ably illustrated ‘by Berthollet, Thomson, and Saussure. Indeed, the account here given may be considered as a-development of that theory. By the latent: heat which becomes sensible in the condensa- ‘tion of vapours, and also by the heat which is frequently ‘evolved in the mixing of liquids, that increase of temperature, which always marks the absorption of gaseous bodies, is ex- plained. The'same liquid absorbs different quantities of ‘dif- ferent gases, and different liquids absorb unequal quantities of the same gas, from the attraction between the absorbing liquids and the gases when liquefied being variable, as is the case among ordinary liquids. Diminution of pressure, or increase of temperature uniformly Jessens the quantity of a» gaseous ‘body 1826], Goientific.Notices-Chemistry. 73 retained by a liquid, because the absorbed gas is itself ‘then in a liquid ‘state; and the volatility of all liquids, whether by themselves or mixed with others, is dependent upon pressure and temperature... The law, however, which Dr. Henry deduced from his experiments upon carbonic acid, viz. that the quantity of a gas which water absorbs is directly proportional to ‘the ressure, is at variance with this theory. It 1s not likely that Dr. Henry would have come to the same conclusion, ‘had he experimented upon the more absorbable gases. In the case of muriatic acid gas, for instance, it is unlikely that he would have succeeded in enipregnaling water with a double portion by doubling ‘the pressure. There may, ‘nevertheless, be an ‘ap- roximation to such a law, when the quantity of gas absorbed 1s inconsiderable, as it is in the case of carbonic acid gas; our knowledge of the laws by which a volatile is retained by a more fixed liquid, being too superficial to enable us at present to decide the point in question. The existence, however, of a general mechanical law of that description is incompatible with ‘any chemical theory which can be given. Supposing such a law to hold, it is remarked by Dr. Thomson, that ‘ the pro- portion of the ingredients in this case is entirely regulated by the-bulk, whereas, in chemical combinations it is regulated by the weight.”, Dr. Thomson, notwithstanding this admission, attempts ingeniously to reconcile such a law'to his modification of the.chemical theory.* | The same objections are applicable to the analogous mecha- nical law, that-the quantity of a gas absorbed, estimated by the bulk, is unaffected by variations in temperature. Such a law -‘would be agreeable to the theory illustrated, if it were true that the pressure of vapours from liquids is exactly proportional to the temperature. But we know that the elasticity of vapours, over their liquids, increases in a much higher ratio than the ‘temperature. Hence we are led to propose a different law, viz. that by increasing the temperature of a liquid, we diminish its capacity to absorb any gas, not in the same but in a much greater proportion. | Dr. Henry and Mr. Dalton have proved, that the amount of any gas, absorbed by a quantity of water in a vessel, depends greatly upon the gaseous residue. This fact is deducible from the supposition, that the gases are liquefied when absorbed. For all liquids continue to evaporate until they are pressed upon by an-atmosphere of their own vapour, equal-in elasticity to that. which they dare capable of evolving at the temperature of the experiment. In a solution of carbonic acid in water, we ought, therefore, to. expect carbonic acid to be given out or to,evaporate, till an-atmosphere of that gas be formed of elas- L > System of.Chem. vol. ii. p. 61, 74 Scientific Notices—Miscellaneous. [JuLy, ticity sufficient to counteract the tendency to assume the eous form of the remaining liquid carbonic acid. If ‘the solution be freely exposed to the air, the whole of the carbonic acid will in a short time assume the gaseous. form, from the impossibility of forming such an atmosphere. But if the solu- tion be exposed to a limited quantity of any foreign gas, the carbonic acid will cease to evaporate, when the elasticity of the gaseous portion can counteract the volatility of the’ liquefied part. The greater the quantity of the foreign gas with which the solution is in free communication, the less carbonic acid will be detained, or would be taken up, were the absorption but commencing. Hence the influence of the gaseous residue, as it is called. > | | i | KON To the partial displacement of one gas absorbed by a liquid, by another gas, parallel cases may be adduced from the mixture of liquids. Thus, if alcohol holding a volatile oil in solution be poured into water, the greatest part of the oil separates, while the alcohol’ unites with the water.—The simultaneous absorption of several gases by a liquid belongs to this class of appearances. From Mr. Dalton’s theory it follows that two gases absorbed into a liquid should really oceupy always the same room as they would occupy, if each of them had been absorbed singly, at the degree of.density which it ‘has in the mixture. This law is inconsistent with the explanation given here; but it has been fully disproved by the subsequent expe- riments of Saussure. ! NR PHOT IS Tie It may be stated in conclusion, that all that is insisted upon in the foregoing sketch is, that when gases appear to be ab- sorbed by liquids, they are simply reduced into that liquid inelastic form, which otherwise (by cold or pressure) they might be compelled to assume. That their detention in the absorbing liquid is owing to that mutual affinity between liquids, which is so common. An affinity which occasions the miscibility of liquids, affects the bulk or density of the mixture, and fre- quently impairs the volatility of the more easily vaporized liquid in the mixture. In this way, the phenomena of the absorption of gases are brought into the same class, as those of the mis- ailedkty of liquids.—(Scots Mechanic’s Magazine.) > _MisceLLaneous, 2. Lieutenant Drummond's Station-Light. We are enabled to furnish some additional particulars to the account of this interesting and ‘useful invention, given in the last number of the Annals, p. 451. — ag SOS Among the applications of the Station-light suggested by the inventor, in his paper on the subject, is the adapting of it to the very important purpose of illuminating light-houses ; which he recommends especially with regard to those light-houses first 1826.) Scientific Notices—Miscellaneous. 75 made by vessels approaching land, The chief distinction of the light emitted. ie the. incandescent lime, when compared with that from the combustion of oil, is a deficiency of the yellow rays; whereas, compared with day-light, it has the same rays im excess... 80 , | : AoW : 3. Butter in a Bog, , bobae » A letter from the Viscount Dunlo, of which the following is an extract, was read at the meeting of the Royal Dublin Society, June 15th, 1826. | “In a bog upon.an estate of Lord Clanearty’s, adjoining Ballinasloe, has just been dug up a tub of butter, which, from the circumstance of the wood-work having been quite rotten, so as to fall off when touched, must be of great antiquity. It was this morning discovered by turf-cutters at the depth of eight feet from the surface of the bog. Upon probing it with a long knife some hard substance was found to resist, in consequence of which it was cut into two pieces. The resistance appears to have arisen from a great part of it having become hard and dry ; about one half of it is in this state, the rest to all appear- ance fresh and’ good, and emitting no smell. : “ The two parts have been put together again, and at present lie in Lord Clancarty’s cellar at Garbally. The marks of the tub on them are quite distinct.” rs set; 4. Luminous Meteor. Qn the 2d of January, 1825, about 5 a.m. M. Antonio Bru- — calassi, on his return to Arezzo, observed, between 8. Giovanni und Montevarchi, a singular electric phenomenon, About a hundred paces off, and at the height of about ten fathoms or less from the ground, appeared, on a sudden, a luminous meteor, of the form ofa truneated cone. This meteor appeared to be formed of a globe of fire situated in its fore part, which was the narrower, and which, by its rapid motion, left behind a track of light, which gave it the appearance of a cone. ‘This light became gradually less intense towards the base, and seemed to split into rays, issuing from the opposite extremity. The whole surface of the cone was illuminated, and cast out sparks of. the greatest brilliancy, in brightness like the electric sparks, but in the effect resembling those exhibited by filings of iron, when thrown upon the flame of a candle. The whole length of the meteor appeared to be about two fathoms, and the diameter of the base half a fathom. At the centre of this base, there was a total absence of light, which formed in that part a dark spot ; the direction of its motion was from west to east, and nearly horizontal, inclining, however, a little towards the earth. Its motion was very rapid; for in less than five seconds it traversed. a space of about 350 paces. During this passage it shed a most brilliant light, so thata certain extent of land was illuminated, "%6 New Scientific Books. . [Juny, ‘as in full day light. The emanations of this luminous ‘body were lost inthe air, instead of being extinguished in the ground; ‘it left behind no smell, produced no explosion or noise of any kind, ‘not even that hissing made by artificial fire works. The night in which this phenomenon occurred was calm, but very cold, and the sky clear. A’great number of shooting stars were seen before and after the appearance of .the meteor. Antologia, Feb. 1825,—(Edin. Phil. Journ.) a = ArticLte XIV, — NEW SCIENTIFIC BOOKS. PREPARING FOR PUBLICATION, The Hunterian Oration delivered last February at the Royal College of Surgeons, on the Natural History of the Oyster, and some of the ‘principal points in its anatomy. By Sir A. Carlisle. A Narrative of a Voyage in his Majesty’s Ship Blonde, under ‘the command of Capt. Lord Byron, undertaken for the purpose of convey- ‘ing to the Sandwich Islands the bodies of the late King and Queen of those Islands; with the natural history of this interesting group of islands, &c. By R.B. Bloxam, MA. Chaplain of the Blonde. JUST PUBLISHED. Euclid’s Elements of Geometry, translated from the edition of Pey- rard ;'to which are added Algebraical Demonstrations to the Second -and Fifth Books. _ By Geo. Phillips, ‘of Queen’s College, Cambridge. PartI. Book 1to6. 6s. Practical Observations on the Convulsions of Infants. By .John -North, Surgeon Accoucheur. i | Practical Observations in. Surgery, more particularly as regards the Military and Naval Service. By Alexander Copland Hutchison. Second Edition, considerably enlarged: 8vo. 12s. _. Delafons’ Description. of a new Patent Instrument for extracting Teeth, and a Patent Method of fixing Artificial Teeth. 5s. ~ __ A Treatise on Diet, with a view to establish some general principles ‘for the prevention and cure of the diseases incident to a disordered state of the Digestive Functions. By A.J. Paris, MD. FRS. &e. 8vo. ¢ 1826.] : New: Patents. 77 ARTICLE XV. NEW PATENTS. L. Zachariah, jun. of Portsea, pawnbroker,. for a. adore a Rada of materials to be used as fuel.— May 8. “ae Dunn, King’ s-row, Pentonville, manufacturer of essence of coffee and spices, for improvements upon the screw press used in the pressing _ of paper, books, tobacco, or bale goods, and in the expressing of oil, extracts, or tinctures, and for various other purposes in whichr great pressure is required.—May 23. T. Hughes, Newbury, Berks, miller, for improvements in the method of restoring foul or smutty wheat, and rendering the same fit for use. —May 23. OF M olineux, Stoke Saint Mary, Somersetshire, for an improvement in machinery for spinning and twisting silk and wool, and for roving, epinnite and twisting flax, hemp, cotton, and other fibrous pubstances. —May-23. T. P. Birt, Strand, coach-maker, for improvements in ebook car tiages.—May 23. ~ J. Parker, Knightsbridge, iron and wire fence manufacturer, for improvements to park or other gates.—May 23. , D. P. Deurbroucgq, Leicester-square, for an apparatus to cool wort, and also for the purpose of condensing the steam arising from stills during the process of distillation,x—May 23. W. H. Gibbs, Castle-court, Lawrence-lane, warehouseman, and. A. Dixon, Huddersfield, manufacturer, for a new kind of piece goods formed by a combination of threads of two or more colours, the manner of combining and displaying such colours in such ie goods consti- tuting the novelty thereof—May 23. J. Smith, Tiverton, Devonshire, lace manufacturer, ‘for an improve- ment on the stocking frame.—May 23. J. Loach, Birmingham, brass-founder, for a self-acting sash fastener, which fastening i is applicable to other purposes.—May 23. R. Slagg, Kilnhurst Forge, near Doncaster, steel manufacturer, for an improvement in the manufacture of springs chiefly applicable to carriages.—May 23. L. J. Marie, Marquis de Combis, Leicester-square, for improve- ments in the construction of rotatory steam-engines, and the apparatus connected therewith.—May 23 J. B. Fernandez, Norfolk-street, Strand, for improvements in the construction of blinds or shades for windows, or other purposes.— May 26. - KR. Mickleham, Furnival’ s-inn, civil engineer and architect, for improvements in engines, moved by the pressure, elasticity, or expan- ih of steam gas or air, by which a great saving in fuel will be effected. —June 6. , H.R. Fanshaw, Addle-street, silk embossor, for an improved wind- ing machine.—June 13, J. Ham, Holton-street, Bristol, vinegar-maker, for an improved proce for promoting. the action of acetic acid on metallic bodies.— une | 7% Mr. Giddy’s Meteorological Journal. — [Juny, ; Arricne XVI. Extracts from the Meteorological Journal he tat the spartmer pr * the Royal Geological Society of Cornwall, Penzance. By Mr E. C, Giddy, Curator. : ‘ | BARoMETER. Reoist. Tuerm. Rain in|: Nisa 1826. | . ‘ ~\100 of Win. Remarks, | Max. | Min. | Mean. |Max.|Min.| Meanlinches! : , May 23, 29°88] 29-84]29-860| 66 | 54 | 60-0 NW |Clear. ‘ - “ 94) 29°74] 29°70}29°720| 64 | 48 | 56-0 N |Clear. 25) 29°70 | 29°70/29-700| 64 | 50 | 57-0 N_ |Light showeté, ~~ 26, 29°63} 29-67 |29-675| 62 | 54} 58:0 NN {Clear: 27) 29°64] 29-62 |29:630| 64 | 52 | 58-0 E__ |Light showérs. 28, 29°70) 29-70 |29-700 64 | 52 | 58:0 NE ht showers 29) 29°74) 29°70/29°720) 64 | 52 580 | NW |Light showers. 30, 29-78| 29°78|29-780| 64 | 54] 59-0 N Clear. © | - 31) 29-80} 29°78 |29-790| 64 | 54 |°59-0 | 0-100) | ears June 1} 29°80) 29:80|29-800| 64 | 50 |° 57-0 N ‘ 2 29°85| 29°84|29-845| 64 | 52 | 58-0 Clear. 8' 30-02| 30-98|30-000} 63 | 52 | 575 NW, Clear. 4 30:08| 30-08|30080} 65 | 54 | 59:5 NW |Fair 5 30-20) 30°20|30200} 66 | 52°} 59:0, NW |Clear. 6 30:15} 30-14|30'145| 70} 53} 615 | oO | NW [Clean -« 7, 30°14] 30:14|30°140| 70 | 56 | 63:0 NE |Fair. 0°10) 30°02 |3( 36 ; ) ‘NE |Cloudy; a shower. 9' 29-88} 29-80|29-840| 70 | 55 | 62-5 | 0510] NE |Thunder storm. -10 29°85} 29-80|29°825| 70 | 55 | 62-5 Var. |Clear. 11) 29°96} 29°95|29°955| 72 | 56] 640) © N |Clear. 12} 30°14} 30°12|30°130| 72 | 56 | 64-0 NW Clear. 13, 30°18} $0°15/30-165| 70 | 58 | 640 NW |Cloudy, clear. 14) 30:12/ 30°12/30-120) 69 | 58 | 63°5 W_. {Clear ; cloudy. 15\ 30°18) 30-16|30-170| 62} 56 | 59°0 NE. |Clear. 16 30-18| 30-16|30°170| 67 | 58 | 62°5 NE |Clear. 17) 80-22 30*22/30-220) 68 | 52 | 60°0 NW |Clear. 18 30°20| 30°20/30-200| 70 | 56 | 63°0 NW {Clear. 19, 30-22 | 30°22|30-220| 70 | 58 | 64-0 NW (Clear 20 30°22| 30-22 ay aa 10} 57 | 63° Var. |Clear. ‘91! 30°22] 30-22/30-220| 68 | 56 | 62-0 Var. |Clear _| 30:22 | 29-62 |29-980| 72 | 48 |. 61-0 | 0-610) NW. RESULTS, Barometer, mean height states oi ides dis RGU L'd ole . 29-980 . Register Thermometér, ditto’. .isisvss ies sys 61-02 Rain, No. 1, 0-610, No.2, 0:810. Prevailing wind, NW. No. 1. This rain is fixed on the top of the Museum of the Royal Geologi Society of Comwall” 45 feet above the to Pe and 143 above the fevel men No. 2. Close to the ground, 90 feet above the level of the sea. , Penzance, June 24, 1826, EDWARD C. GIDDY. 1826.]. . 0 Mr. Howard's Meteorological Journal. "9 Articte XVII. METEOROLOGIGAL TABLE. ALI oats | .|->) Baromerer. ..| Tuermometer. | —. at 1826, | Wind. |. Max. | Min. | Max |. Min. | Evap. | Rain. 5th Mon.| ~ : aay te May 1IN. Wj: 3043 |°°30°97" | 58 J 29 | — ON ORS). ‘80°27 30°20 64 bE — 3IN E|. 30:22 .| 30°20 50 37 — 13 4\N W) 30:22 30°20 50 38 — — -5IN. E| 30°20 SO°19. | 55 38 — 6IN E} 3022 | 3020; 50 | 36 | — 16 TIN’ “Bl 3022 30°21 54 38 —_ SINE! 30°22 80:22. *|' 62 28 oa QIN. E| 30°22 30:22 66 36 —_ 10\N W) 30:24 | 30°18 65 | -36 ~— 11|/S E| 30:39 30°24 68 37 S97 12IN. E|: (30°40. |. 30°39 56) "|: 37 —_ 13|IN' E| 30-41 30°28 62 29 | — 14IN. EE}. 30°28 30°27 64 | 29 | —~ 15IN. E| 30:30 | 3027 | 61 |. -32.4.— 16S ° E| 30°30 30°26 70 45 — 17IN W 30°26 30°24 74 45 oo ( 1858S E| 30°24 30°08 76 | 45 — O04 19S W| 30°08 | 29:92 | 75 | 50.) — 10 20, E | 30°18 29°92 68 37 -96 2iN Wi). 30°19 S18: 1... 72 44 —_— 22IN Wi 30°19 30°14 75 | 42 — 23} N 30°14 30°01. | 70 48 no , 24\N Wi). 30°01 29°89 69 50 — 68 25N E| 29:39 | 29°84 | 70 |° 52 | — 16 26|S E} 29°96 | , 29°84 68 |. 48 — 03 27, +E 30°04 2996 |. 71 45 oa 28} N 30°04 29:93 65 51 _— —_ Q9IN.. E| 30°04 29°93 55 50 a 1°34 30\IN W| 30:08 30°04 65 55 —_ 07 31} E 30°08 30°03 60 51 "92 06 3041 | 29:84 | 76 | 28 | 2:85 | 2-77 The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. ‘on the day indicated in the first column, A dash denotes that the result is included in the next following observation. : 80 Mr. Howard’s Meteorological Journal, (Jury, 1826. ks REMARKS. Fifth Month.—1, 2. Fine. 3. Showery. 4. Cloudy. 5. Fine. 6. Hail showers during the day. 1, 8. Fine. 9; Fine: very distinct solar halo about one, ‘p.m, of unusually large diameter. 10. Cloudy. 11—23. Fine. 2426, Showery, 27, 28. Fine. 29. Very rainy day. 30. Drizaly. 31, Cloudy, fit . RESULTS. Winds: N, 2; NE, 13; Ey; SE,4; SW, 1; NW, ® Barometer: Mean height ee Wal Ogee : For the month. ees URED pp ed A Sy Ber: WM ndied: 30-156 inches. - Thermometer: Mean height : < For the month. .......scccreccssecccscocscscsecnce 525329 ~ Evaporation ,. soe ee eran eeesanseenscesnceeeepeeeataseeasssenenere 2°85 in. Rain. Poem R ROT Hee ee et eeeaeEeeeeeees 4iC ie cele dae bieis de sede 2°77 Laboratory, Stratford, Sixth Month, 21, 1826. - _ R. HOWARD. ANNALS oO F ‘ PHILOSOPHY. AUGUST, 1826. ARTICLE [. An‘ Account of a curious Phenomenon observed in the Moon. By the Rev. J. B. Emmett. : (To the Editors of the Annals of Philosophy.) GENTLEMEN, Great Ouseburn, near Boroughbridge, July 5, 1826. — Tue following communication will, perhaps, be interesting to some of your readers: the observations were made. with the greatest care, and with a very fine telescope. “On the 12th April, 8°, whilst. observing, that part of the moon called Palus Mzotis by Hevelius, with an excellent Newtonian _ reflector, which has an aperture of six inches, and which bears a. beautifully distinct. power of 800, and upwards, the most southerly of two spots in Mzotis, called Alopecia by Hevelius, and the most northerly, not. noticed by Hevelius or Cassini, but .. which jis included in. Russell’s beautiful maps, were seen as ~ usual. . Between, and-very nearly in a right line joining them, _ but nearest to the N spot. (the distance from the N spot being about one-fourth that from the S) appeared a very conspicuous spot, wholly enveloped in black. nebulous matter, which, as if carried forward by a current of air, extended itself in an easterly “direction, inclining a little towards the 8, rather beyond the margin of Mzotis. YN The powers. used were 70 and 130; the | state. of the air was such, that greater : magnifying powers could not be employed with advantage. da 3% April 13%, 8" to 9"; the cloudy appear- = E ance. was reduced, both in extent and intensity : the spot from which it seemed to issue, had. ah ste more distinctly visible ; it resembles the small circular, or if near the limb, as in this instance, New Series, vou, X\1. G 3 Meotis 82 Rev. Mr. Emmett on a curious Phenomenon [Ave. elliptical cavities, which are visible in almost every part of the moon. ae Bon 3 April 17*, 9". Scatcely/a itraeé Of the nebulous matter, Powers 70, 130, 200; all which were used in the last obser- vation. May 11, 12, 13, 15; June 9,10. The three spots distinctly visible ; but #6 trace Of the ‘nebulous up sn; Powers, 130, 200, 400, 800. Appearances the-saine 1} the*above-men- tioned days, with an aerial refractor of 18 feet ; powers 60 and 200. The general appearance is represented in outline in the figure, in which a represents Alopecia; the N spotin Russell’s maps, but not noticed by Hevelius or Cassini; c the spot which is the subject of this paper, surrounded with the nebulosity. The nebulous appearance here spoken of is not to be confounded with a darkish shade which is await to be seen near the same part of Meotis, and which was distinctly visible at the same time: the nebulosity in question was very much’ blacker; it was so conspicuous as fo’ strike the eye immediately. On the 12th April. it. was.s0 intense: that'the spot ¢ could not be very readily discerned, It was a more conspicuous object than any spot.in Mzotis, and therefore it has not been permanently visible ; had it been so, it is almost impossible that Hevelius, Cassini, and Russell, who have noticed far Tess conspictious objects, within a few seconds of it, should ‘all have omitted itj and this part of the moon being one’ which during several years, for reasons which will appear when a sufficient series of obser- vations shall have been made, [have examined very minutely, I can positively state, that the nebulous appearance neyer pre- sented itself, in any of the numerous observations I have made, from the year 1814 to the present time. « Respecting thé spot-c from which the:nebulosity seemed to issue which is ‘now visible, f cannot aie od ee It is not noticed by Hevelius, Cassini, or Russell; and it is well known that the latter devoted nearly 30 years'to making his maps; that he used” the ‘best instruments ; and that he’ has carefully delineated almost evety visible speck. 1 do-not recollect to’ haves seeh it previously to the 12th of April. | | oe Paes L, On Io I regret that 1 had no scientific friend with me whose testi- mony might give additional weight to this account’ of ‘the observation of the 12th April ; however, IT hope that’ some other astronomers shay have been fortunate enough to see the phieno- menon. I should have communicated the intelligence’ at an earlier period, had it not been requisité to observe the moor at about the same age afterwards: this has been’ done during two successive lunations. on ode IOGe aGs.. Yeast It is scarcely safe to hazard a conjecture respecting the cause of this phenomenon ;: I shall, inakeite; tieehy ropose a acty Was it the smoke of a volcano? or was it clot matter? The . 1826.} r alaodiesl in the Moon. | 83 former part of the query might have been decided by observa- tion about three or four days after opposition; but the air was uniformly cloudy, and the moon quite invisible. . ; The moon presents the same general aspect which it did to the first telescopic observers; yet from my own observations I am convinced that if a number of astronomers would take sepa- rate and small portions of the lunar disc, and observe the same on every clear evening with large instruments, and make use of high powers, as 500 or 600, that changes would be observed ; from such observations, important sien 36 may be derived, some of which are pointed out by Hevelius in his Selenographia. P.S. June 10%, 8"; there remains a little blackness about the spot c; it is rather faint, of small extent, and nearly uniformly iffused. : J.B. Emmert. | ARTICLE EE. | ; A New Catalogue of the Fall of Stones, Iron, Dust, and soft Substances, dry or moist, in Chronological Order.. By M E.F.F, Chladui.* | ie _In this corrected and complete catalogue which M. Chladni has sent me, the sign ? indicates those falls which this able _ haturalist does not consider as perfectly verified —(Ar.) Falls of Stones or Iron before ot Commencement of the present aie da; Worst sis 91478 years before our era in Crete; the thunder-stone of which Malchus speaks, and which was probably believed to be a symbol of Cybele. Chronicle of Paros, 1.18 and 19. © The shower of stones mentioned by Joshua was probably nothing but hail.) = ne? 1200,—Stones preserved at Orchomenos. Pausanias. 21168.—A mass of iron on Mount Ida, in Crete. Chronicle of , Paros, 1. 22. | : | is 2705 or 704.—The Ancyle, probably a mass of iron, nearly of “> “the “same form as that of the Cape and of Agram. i Plutarch. . | 654,—Stones on Mount Albanus. Liv, i. 30. 644.—In China. De Guignes. ~ 3 by | -465.—At gospotamus. Plutarch, Pliny, and others. A ~<- gtone near Thebes. Scholzast on Phidur. | am or an China. De Guignes, and’ General History — of . China. | 205 or 206,—Ignited stones. Plutarch, Fab. Max. c. 2. ’ * From the’ Annales de Chimie, ° G2 84 M. Chladni’s New Catalogue of Aerolites. [Ave. 192.—In China. De Guignes. 176.—A stone in the lake of Mars. Liv. uli: 3, bf) 90 or 89.—A shower of bricks. Pliny and Jul. Obs. 89.—In China. De Guignes. 56 or 52.—Spongy iron, in Lucania. Pliny. 1.46,—Stones at’Acilla. | Cesar: 38, 29, 22, 19, 12, 9, 6.—Falls of stones’ in China. De Guignes. | Stones fallen at pandeteratined pvp _ The mother of the gods fell at Pessinus.. The Elagabalus at Emisa, in Syria. The stone preserved at Abydos, and that of Cassandria. Phin tthe black stone and another preserved in the caaba. or mple at Mecca. e stone preserved in the coronation chair of the kings of England is not, as has been’ believed, a meteoric stone.) Falls of Stones or Iron after the Conimencement of our Era. In the years 2, 106, 154, 310, and 333, some stones: fell in China. Abdel Rémusat, Journ. de Phys. May, 1819. (The stone which it was pretended fell from heaven in 416, at Constantinople, of which Sethus Calvisius makes mention in his Op. Chronolog. was only a stone from Constantine’s great column, which, by its fall, injured the pedestal.) . ..A stone in the country of the Vocontini. Piiny: 452,—Three large stones in Thrace, Cedrenua and Marcel- linus. 6th century.—Stones on Mount Libanus, and’ near Emisa in Syria. Damascius.. 2870 (or thereabouts.) —Stones near Bender, ‘in. Arabia. __ Koran, 8,16; cv. 3 and. 4, andthe Commentators. 616.—Stones in China, Abel Rémusat... 648.—An ignited stone at Constantinople —Abel Rémusat. 839.—Stones in Japan. Abel Réemusat. | 852, in. July, or August.—A_ stone at ‘Tabaristan. De Sacy and Quatremére. | 856, in December.—Five. stones in. Egypt. Lhe same. 885.—Stones in Japan, Abel Rémusat.. 897.—At Ahmed-Dad. Quatremére; according to the. Chron. Syr. in 892. ; 921.—Large stones at Narni.. Manuscript Chronicle of the monk Benedictus de Saint- Andrea, which is in the library of the Prince Chigi, at Rome. 951.—A stone at Augsbourg. A/b. Stad.and others. 998.—Stones at Magdehoure. Cosmas and Spangenberg. 1826.] .M. Chladni’s New Catalogue of Aerolites. 85 1009, or soon after.—A mass of iron inthe Djorjan. Avicennes. (They have murdered the name in Lurgea and Cordova.) 1021, between the 24th of July and the. 21st of Aug.—Stones in Africa. De Sacy. 1057.—A stone in Corea. Abel Rémusat. 1112.—Stones or iron, near Aquileja. Valvasor. 1135, .or 1136.—A_ stone at Oldisleben. | Spangenberg and others. | | 1164, at the feast of. Pentecost.—Iron in Misnia. Geog. Fabricius. 1249, 26th July.—Stones at Quedlinburg, &c. . Spangenberg : and Revander. | 213th century.—A stone at Wurzburg. Schott. Phys. Cur. Between 1251 and 1363 sone tbe at Welikoi-Ustiug, in Russia. 3 Gilbert’s Ann. vol. 3 | : . ?1280.— A stone at gate in Egypt. De Sacy. 1300, or thereabouts.— Large stones in Arragon, according to a manuscript Chronicle preserved in the National Museum of Pest, in Hungary, being the continuation to that of Martinus Polonus.. 1304, 1st October.—Stones at Friedland or Friedberg. Kranz and Spangenberg. 1328, 9th Jan.—In “the Mortahiah and Dakbaliah. Quatremére. ?1368,—In the country of Oldenburg, a mass of iron. Siebrand | Meyer. |. 1379, 26th May. —At Minde, in Hanover. Lerbecius. 1421 —A stone in the island of Java. Sir Thomas Stamford Raffles, vol. ii. p. 137. ? 1438 —-Spongy stones at Roa. Proust. ? ....—A stone near Lucern. . Cysat. 1474.—Near Viterbo, two large stones. Biblioteca Italiana, ‘vol. xix. (Sept. 1820) } p. 461. 1491, 22d March.—A stone near Crema. Szmoneta. 1492, 7th Nov.—At Ensisheim.: 1496, 26th or 28th Jan.—Stones at: Cesena, &e. »Buriel and - Sabellicus. 1511, near the middle of September.—A great fall of stones. at Crema. Giovani del Prato, and others. | 1516. —In China, two stones. Adel ’ Rémusat. 1520, in May.—Stones in Arragon. » Diego de Sayas. 11528. —Large stones at. Augsburg. — Dressert Chron. Saxon. ? 1540, 28th April—A stone in the Limousin. Bonav. de Saint~ Amable. 1540 to 1550.—A\-mass of iron in. the forest. of Nannhof. Albinus Meisniche Bergchrontk (that is to say, Chronicle of the Mines of Misnia). ...—lron in Piedmont. Mercati and Souder 1552, 19th May.—Stones in Thuringia. Spangenberg. 86 M. Chiadni’s New Catalogue of Aerolites. Ave. 1559.—Stones at Miskoltz, in Hungary. Isthuanfi, in his Hist. Hu 1561, 17th ay —At T and Eilenbourg (described by Arcem Juliam). ba and De Boot. 1580, 27th May.—Stones near Gottingen. Bange. 1581, 26th July—A stone. in Thuringia. Binhard Oleartus. 1583, 9th Jan.—At Castrovillari. Costo, Mercati, and tenperate. 1583, 2d March. In Piedmont. Mercati. — 1596, lst March. Stones at Crevalcora. Miturelli. ) . In the same century.—A stone in the kingdom of Valencia. Casius, and the Jesuits of Coimbra... 1618, in August.—A great fall of stones. in Stiria. Fundgruben der Orienis. (Mines of the East, by M. de eran’ 1618.—-A metallic mass in Bohemia. Kronland. 1621, 17th April—A mass of iron near Lahore. Jehan Guir.. 1622, 10th Jan.—A stone in Devonshire. Rumph. - 1628, 9th April.—Near Hatford, in Berkshire. Gentlem. Mag. 1634, 27th Oct.—Stones in Charollais.— Morinus. q 1635, 7th July.—A stone at Calce. Valisnieri. 1636, 6th March.—In Silesia. Lucas and Cluverius. 1637. (not 1627), 29th Nov.—In Provence. Gassendi. 1642, 4th Aug.—In Suffolk. Gentleman's Magazine. 7 1643 or 1644.—-Stones in the sea. Wurfbain. 1647, 18th Feb.—A stone near Zwickau. Schmid. 1647, in Aug.—Stones in Westphalia. Gzdbert’s Ann. Between 1647 and 1654.—A mass in the sea. Willman. 1650, 6th Aug.—A stone at Dordrecht. Senguerd. 1654, 30th March.—Stones.in the island of Funen. Bartholinus. Lie mlliy Varsovia, a large stone. Petr. Boredlus. -...—At Milan, a small stone, that aitled a Franciscan. Museum Septatanum. (The account of stones fallen in 1667 at Schiras appears fabulous.) | 1668, 19th or 2lst June.—A great fall of stones at Verona. Valisneri, Montanari, Pr. Carli, 1671, 27th Feb.—Stones in Swabia. Gilbert’s Annals, vol. 33. 1674, 6th Oct.—Stones near Glaris, Scheuchzer. i 2 Between 1675 and 1677.—Stones near Copinsha. Wallace and Gent. Mag. July, 1806. 1677, 28th May.—Stones. at Ermendorf, which probably. con- tamed copper. Misc. Nat. cur. 1677, 5 1680, 18th May.—Stones at London. King. 1697, 13th Jan. near Sienna. Soldant, according to Gabrieli. 1698, 19th May.—A stone at Waltring. Scheuchxer, 1706, 7th June.—A stone at Larissa. Paul Lucas. 1715, 11th April.—Some stones not far from Stargard, in Pome- rania- Gilbert’s Ann. vol..71, p. 215. 1722, , en near Scheftlar, i in Freisinge. Meichel- ec 1826.) Mi Chladni’s.New Catalogue of Aerolites. 87 1723, 22d June.—As:Plescowitz. ;; Rost .and Stephng. (The’ pretended ‘fall | of. metal in /1731-at. ieeeice was only an electrical een of diops of rain, vot) for Dom Stalley does: not say that there fell drops of ignited and melted mein, but there fell, as it were, drops, Xe.) 1727, 22d July.—A fall near J iioachite, in ( Bolistbass “Steping. 1738, 18th. ‘Ang Near Carpentras.:.: Castillon... + 1740, 25th ak —Stones.at eiieado) Gilbert’s Annals,-vol. 50. 1740. and 1741, in winter.—A large stone in Greenland. :: ?1743.—A stone at Liboschitz. Stepling. (Basalt the same _ remarked in theyear 1723.)...>.. 1750, Ist Oct.~-Stones. near Coutances.. Fhtard and La 1751, 26th May.—Iron at Hradschina, near Agrams =) 1753, 3d July.—Stones at Tabor.» Stepling and Mayer. . 1753; in September.—At Laponas, Lalande and Richard. 1755, in July.—A stone in Calabria. | Domin. Tata. i 1766, in July.—At Alboreto....Troili,, 2.1766, ith Aug.—At Novellara..» Trotlz. (Perhaps a stone _ melted. by lightning.),. > 1768, 13th Sept.—A stone at Luce. Mem. de PAc. ss. —Avstonevat Aires: Memade LAc: 3 1768, 20th Noy.—A stone at Maurkirchen. Imhof. 1773, 17th Nov.—A stone at Sena, in Arragon. Proust. 1775, 19th: een ih Reodach, :im ‘Cobourg. Gilbert’s Ann. & op woli23, 1776 or 1776.—Stones at Obruten in Volhy ies — Gilbert’ s Annals, vols 31.) 1776 or 1777, an Jan. or Feb.—Near Fabriano. Soldant and » fis Aanoretii: ' 1779.—-Stones: at Pettiswood, in [reland. Gent. Mar. 3 1780, sy 0 -—Near Beeston in England. ldeers ‘Evening ost 1780, or thereabouts.—Masses of iron in the fecriinbe! of Kins- dale, and between West River Mountain and Connec- ticut. Quarterly Review, No. 59; April, 1824. 1782.—A stone near Turin. Vata and Amoretti.. 1785, 19th Feb—Stones at Eichstaedt. Pickel and Stutz. 1787, 1st Oct.—In the province of Charkow, in Russia. Gil- bert’s Ann. vol. 31. a hee 1790, 24th July.—A great fall at Barbotan; 8c. 1791, 17th May.—Stones at Castel-Beradenga. Soldani. 1791,* 20th Oct. —At Menabilly, in Comwall. King. * The late Philip Rashleigh, Esq. of Menabilly, showed me several years ago some models of pieces of ice, inclosing hail, which fell in his neighbourhood ; and his brother, my. friend the Rev. Peter Rashleigh, of Southfleet, lately showed me another, witha ticket attached, stating the storm to have occurred on the 20th Oct. 1791, the day and year mentioned in the text. The latter gentleman also informs me'that he never heard 88 M. Chladni’s New Catalogue of Aerolites. [Av6. 1794, 16th June.—In the environs of Sienna. 1795, 13th April_—AtCeylon.—Le Beck. 1795, 13th Dee.—A stone, in Yorkshire. © 1796, 4th Jan—Near Belaja eeceeal) in Binsin. Gilberts” _. Annals, vol. 35... 1796, 19th Feb. —In Portugal. Sout De hpi 1798, 8th or 12th of March.—At Sales. De.Drée, &e. 1798, 19th Dec.—Stones in Bengal. Howard, Valentia. 1801.—On the island of Tonneliers.—Bory de Saint- Vincent, 1802, in September.—Stones in Scotland. veer é Mogens, “Oct. 1802, . . 1803, 26th April.—Stones in the environs of Aigle. : 1803, 4th July.—At East Norton. Phil. Mag. and Dart Brit, 1803, 8th Oct.—A stone near Apt. . 1803, 13th Dec.—Near Eggenfe de. Imhof. 1804, 5th April.—Near Glasgow. | Phil... Mag. and Bibl. Brit. From 1804 to1807.—At Dordrécht. Van Beck Calkoen. .— 1805, 25th March.—Stones.at Doroninsk, in Siberia. -Gilbert’s — _ Annals, vols. 29 and 31. 1805, in June —Stones at Constasineyeve Kougas-Ingigian 1306, 13th March.—At Alais. 1806, 17th May.—A stone in Hampshire. Monthly Mag. 1807, 13th arch.—Near Timochin, in Russia. _ Gilbert’s Annals, 1807, 14th Dec.—Stones near Weston, in Lonubesiont:/ eae i 1808, 19th April.—At Borgo San-Donino. ta 2.3 and Spag- non. 1808, 22d May.—Near Stannern, in Moravia, . 1808, 3d Sept.—At Lissa, in Bohemia. | De Schreibers. ? 1809, eh June.—In the sea, near North America. Medical osit.and Bibl. Brit. : 1810, 30th ‘*; an.—In Caswell, in America. Pil. Mag. and Medical Reposit. 1810, in July.—A large stone at Shahabad, in India. 'The meteor caused greathavock. Phil. Mag. vol. 37. 1810, in August. ——A stone ‘in the oa of Tipperary, in Ireland. William Higgins has published its analysis. 1810, 23d Nov.—Stones in Charsonville, near Orleans. 1811, 12th, 13th March. —A stone in the premnes of Paltawe, in Russia. Gilbert’s Ann. vol. 38. 3 1811, 8th July.—Stones at Berlanguillas. 1812, 10th April.—Near Toulouse. LY | 1812, 15th April—A stone at Erxleben. Gilbert’s Annals, vol. — 40 and 41. , 1812, 5th Aug.—At Chantonay. Brochant. that any meteoric stone, or other substance, besides the ice, fell at that time in the neigh. bourhood of Menabilly.—This singular Phenomenon appears, b aire to have been mistaken for a fall of meteoric stones or iron.—J, G. C. 1826.}.. MM. Chiladni’s New Catalogue of Aerolites. 89 1813, 14th March,;-—Stones ‘at Cutro, in Calabria, during the fall r+! ogy quantity of red dust. Bibl. Brit. October, 21813, in summer.—Many stones near Malpas, not far from Chester. Annals of Philosophy, Nov. 1813. (This account does not appear worthy of entire confidence, because it is anonymous, and above all this event is not | » elsewhere noticed.) ~ A 3d 1813, 10th September.—Stones in Limerick, in Ireland. Pail. oees Mag. and Gent. Mag. . i 1813, 13th December.—According to Nordenskiold. Ann. de Chim. vol. 25, p.78. te 1814, in. March.—From an account communicated to the Academy of Petersburgh. Stones in the neighbour- hood of Loutolax and Sawitaipal, not far from Wi- borg, in Finland. These stones do not contain nickel. ».+s (Mr. Murray, in the Phil. Mag. July, 1819, p. 39, speaks ; of a stone fallen at Pulrosein the Isle of Man, without fixing the date; he says the event is certain, and that ~ the stone was very light, and resembled a slag : it there- Jo daca apa resemble the stones that fell in Spain, in 1814, 3d Feb.—A’ stone near Bacharut, in Russia. Gilbert’s Annals, vol. 50. : 1814, 5th Sept.—A stone near Agen. | : 1814, 5th Nov.—-In Doab, in India. Phil. Mag.; Bibl. Brit. ; Journal of Sciences. ox tow an 1815, 18th Feb.—A Stone, at Duralla, in India. Phil. Mag. Aug. 1820, p. 156. 3 1815, 3d Oct.—At ai assigny, near Langres. Pistollet. Amn. de Chim. ; | 3 1816.—A stone at Glastonbury, in Somersetshire. Phil. Mag. 21817, between the 2d and 3d May.—There were probably : -some masses fell in the Baltic sea: after the appear- ance of a large - meteor at Gothenburg, a shower of fire was seen at Odensee, descending very rapidly towards | > the south-east. Danish Journals. 3 21818, 15th Feb.—A large stone appeared to have fallen at Limoges, in a:garden to the south of the town. After the explosion of a large meteor, a mass which fell . made a hole in the earth equal in size to a large cask. ae de France, and Journal de Commerce, 25th Feb. (The mass should have been dug up, and it would even still be desirable to do so.) 1818, 30th March.—A stone near Zaborzica, in Volhynia. _. (Analysed by. M. Laugier.) Ann. de Museum, 17 ann, Second Number. 90 M. Chladni’s New Catalogue of Aerolites. [Ave . 1818, 10th Aug.—A_. stone at Slobotka,’in:/the!) ‘province’ of molensk, in Russia, according to several journals. 1819, 13th June.—At Jonzac, Department of a Charente. . These stones do not contain nickel. - ai 81st ' 1819, 13th Oct.—Stones neat. Politz, not far: frotia Gera, or ois vad in the Principality: of Routan vo gid s Ann. vo ; 21820, between the 2Ist and 22d Aisle oui ree night at _ Vedenburg, in Hungary... Hesperus, vol, 27, cal. 3. | ¢{ 1820, 12th J uly.—Stones near ikna i in the circle of Dunabor | province of Witepsk, in Ramoinn ear Grotthus Gilbert’s Ann. vol. 67. — 1821, 15th. idplaas Stones near Juvenas. ‘They do not ota 2 mickel | 1822,.3d June. At Asian “Ann. de Chintie’. 1822, 10th Sept.—Near Carlstadt, in Sweden. » 1822, cygrt 2 pt-—Neae Baffe, Canton. of pina Departement es. Ann. de Chim.» ©. 1823, wh pel ear Nobleborough, in Ameriea. “Silliman’s Aeberideet Koma ebhi7 sido ys i 1824, near the end of Gaaasiiy petsMaalire stones near Aruaito, in the territory of Bologna. One of them oF Bolen. 12 pounds is preserved in’ the ng ins ie! Diario di a 1824, the beginning of Feb.—A large stone in. the ‘province of _ Irkutsk, in Siberia... Several journals.» 1824, 14th Oct pel ear Lebrak, circle: of Beraun, in Soke. The stone is. preserved i in the rg gh we of Prague. a 4 | Masses of Iron pribants é Meteoric ena sige The masses of iron, probably meteoric, are distinguished by the presence of nickel, by their texture, by their malleability and their insulated position. Some of these masses are spongy or cellular; the cavities are filled with a stony substance, similar to ges Amongst these, we must place, he mass ieacol Er Pallas, in Siberia, the meteoric origin of which was known to the Tartars. | ? A piece found between Eibenstock and Johanngeorgenstadt. A mass preserved in the Imperial Cabinet of Vienna, coming probably from Norway. A small mass, weighing four pounds, now at Gotha. Other masses are solid; in which case the iron consists of rhomboids or octahedrons, composed of Jayers, or parallel folia. The only fall known of masses of this kind is that at Agram, in 1751. Some others similar have been found :— On the right bank of the Somme fs river. i Compngnas, Forster, Golberry. 1826.) M. Chladm’s New Catalogue of Aerolites. 91 At the Cape of Good Hope. Van Marum and De Dankel- mann. At Mexico, in different places. Sonneschmidt, de Humboldt ; see also the Gazette of Mexico, vols. l-and 5. At Brazil, in the province of Bahia. Wollaston and Mornay. In the jurisdiction of Saint Jago del Estero. Rubin de Celis. At Elbogen, in Bohemia. Gzlbert’s Ann. vols. 42 and 44. Near Lenarto, in Hungary. Gulbert’s Ann. vol. 49. Near the Red River. The mass was sent from New Orleans to New York. American Mineralogical Journal, vol..1. Col. Gibbs has analysed it, and found it contained nickel. , _ (There are other similar masses in the same country, accord- ‘ing to The Minerva of New York, 1824.)° ' In the environs of Bitbourg, not far from Treves. (This mass weighs 3300 pounds; it contains nickel. The analysis made by Col. Gibbs is in the American Mineralogical Journal, vol. 1.) Near Brahin, in Poland. (These masses, according to the analysis of M. Laugier, contain nickel and a little cobalt.) . In the republic of Colombia, on the eastern Cordillera of the Andes. Boussingault and Mariano de Rivero, Ann. de Chim, vol. 25. At some distance from the northern coast of Baffin’s Bay, in a place called Sowiallik. There are two masses; one appears solid, the other is stony, and mixed with pieces of iron, of which ‘the esquimaux makea sort of knife. Capt. Ross. e- ? Perhaps we must place in this class a large mass nearly 4 _ feet high, found in the eastern part of Asia, not far from the - source of the Yellow River, and of which the Moguls, who call it Khadasutsiiao, that is to say, 5 rock, say, it fell after a fiery meteor. Abel Rémusat. ‘There exist masses of problema- tical origin. Of this number are :— , A mass at Aix-la-Chapelle, which contains arsenic. Gilbert’s Ann. vol. 48. A mass found in the Milanais. Gzlbert’s Ann. vol. 50. The mass found at Groskamsdorf, containing, according to Klaproth, a little lead and copper. | (lt appears that they fused it, and that the pieces preserved at Freyberg and Dresden are only fused steel, substituted for the fragments of the primitive mass.) rai Falls of Dust and soft Substances, dry or moist. All that has been observed in these falls makes us presume they do not differ materially from falls of stones. Sometimes they have been accompanied by falls of stones, a8 well as by fiery meteors. The dust appears to contain nearly the same substances as the meteoric stones. There appears no other difference but in the rapidity with which these heaps of chaotic matter dispersed in the universe arrive in our atmosphere ; but, 92 MyChladni’sNew Calalogie of Acrolites: — [Ave. from that time, these. substances must undergo, more or less, great changes, according to the intensity of the heat which the compression develops in the air. In the red and black. dust, the oxide of iron is probably the principal colouring matter. In the black dust, there is no doubt carbon will also be found. ‘I consider the black and very friable stones which fell at Alais in 1806, as affording the passage trom the black dust to common meteorites, the heat not having been sufficient to burn the carbon of these stones and fuse the other substances. In the year 472 of our era (according to the chronology of Calvisius, Playfair, &c.) the 5th or 6th of November, a great fall of black dust (probably in the environs of Constantinople) ; the sky seemed cn fire. Procopius and Marcellinu attributed it at Vesuvius. Menea, Menolog. Grec.; Zonaras, Cedrenus, nes. | P652.-At Constantinople, a shower of red dust. T’heophanes, Cedrenus, Matthew Eretz. 743,—A. meteor, and dust in different places. T’heophanes. ...—In the middle of the ninth century. Red dust, and matter resembling coagulated blood. Continuat. du - Georg. Monachus, Kaxwini, Elmazen. 869.—Red rain in the neighbourhood of Brixen during three days. Hadrianus Burlandus. (Probably this pheno- : menon may be the same as the preceding.) | 929.— At Bagdad. Redness of the sky and a fall of red sand. Quatremere. 1056.—In Armenia, red snow. Matth. Eretz. 1110.—In Armenia, in the province of Vaspouragan, in winter, ina dark night, fall of an inflamed body in the lake Van. The water became the colour of blood, and the earth was split in different places. Matth. Eretz. 1222 or 1219.—Red rain in the environs of Viterbo. Bibi. Jtaliana, vol. 19. Bt ght. 1416.—Red rain in Bohemia. Spangenberg. | ?.,,.—In the same century at Lucern, fall of a stone and of a mass resembling coagulated blood, with the appearance ofa fiery dragon (or meteor). Cysat. 1501.—Rain of blood in different places, according to some chronicles. 1543.—Red rain, in Westphalia. Suni Commentarii. 1548, 6th Nov. (probably in Thuringia).—Fall of a ball of fire, : with much noise. A reddish substance was afterwards found on the ground, resembling coagulated blood. Spangenberg. 1557.—In Pomerania. Large plates, of a substance resembling coagulated blood, Mart. Zeiler, vol. 11. epist. 386. 1560, Whitsunday.—Red rain at Emden and Louvain, » &c. Fromond. fpxyall | 1826.] M. Chladni’s New Catalogue of Aerolites. 93 1560, 24th Dec.—At Lillebonne, a fiery meteor and red rain. Natalis Comes. 11582, 5th July —At Rockhausen, not far from Erfort, fall ofa large quantity of a fibrous substance resembling human hair, at the end of a dreadful tempest, analogous to those produced by earthquakes. Michel Bapst. 1586, 3d Dec.—At Verden (in Hanover), fall of much red and blackish matter, with lightning and thunder (fiery meteor and detonation). "This matter burnt the planks on which it fell. Adanuscrit: de Salomon, Senator at _ Bremen. 1591 —At Orleans, at the Magdalen, rain of blood. Lemaire (Ln.) 1618, in Aug.—Fall of stones, a fiery meteor, and rain of blood in Stiria. De Hammer. 1623, 12th Aug.—At Strasburg. Red rain. ies Habrecht, in a-memoir printed at Strasburg i in’ 1623. 1637, 6th Dec.—Fall of much ‘black dust in the Gulf of poe | and in Syria. Phil. Trans. vol. 1. p. 377. 1638 —Red rain at Tournay. 1643, Jan.—Rain of blood at: Vachingen and. at. “Weinsberg, according’ to a Manuscript. —— an the town of , Heilbronn. 1645, 23d or 24th Jan.—At Bois le Duc. 1640, 6th Oct.—Red rain at Brussels. Kronland and Wende- linus. 1652, May. —A viscous mass, after a luminous meteor, between Sienna and Rome. Miscell. Acad. Nat. Curios.; ann. ~ 9; 1690. 2 1665, 23d March.—Near Laucha, not. far from» Naumbutg, there fell a fibrous substance, like blue silk, in large uantities. Joh. Praetorius. | acre! 1678, {9th March ey pw snow near Genoa. ‘Philos: Transac. 1678. , pte dist January, near Riswitoriss in Courland, and at the same - time in Norway and Pomerania.—A ‘large quantity of a membranous substance, friable and blackish, resem- bling half burnt paper. Miscell. Ac. Nat. cur. ann. 7, pro. ann. 1688 in append. (M. the Baron Theodore de Grotthus has analysed a portion of this substance which had been preserved in a cabinet of natural | « history, and found. in it silica, iron; lime, carbon, magnesia, a trace of chromium and sulphur, but no nickel.) : 1689.—Red.dust at Venice, &c.. Ss lioseiui | 1711, 5th and 6th May.—Rain at Orsion, in Sweden. Act. Lit. Suecia, 1731. 1718, 24th March.—Fall of a globe. of fire, in. the island of 94 M. Chladni’s New Catalogue of Aerolites. [Ave, Lethy, in India. A gelatinous matter was found after- wards. Barchewitz. 1719,.—Fall of sand in the Atlantic Sea (lat. 45° N. leng, 322° 45’), accompanied by a luminous meteor. Mem. de f Acad. des Setences, 1719, Hist..p.23.. This sand _deserves to be examined with more. attention. 1721, towards the middle of March, Stutgard.—A meteor and red rain in great quantity, according to a note written the 2ist March by the ounsellor. _ Vischer. 1737, 2lst May.—A fall of earth attractable by the magnet, on the Adriatic Sea, between Monopoli and Ligsa. fani~ / chellt, in the Opuscoli di Calogera, vol. 16... 1744.—Red rain at St. Pierre d’Arena, near Genoa. Richards. 1755, 20th Oct.—On the island of Jetland, one of the Orkn Black dust that did not come from Hecla. Phi Mo . Transac, vol. 50. 1765, 13th Nov.—Redness. of the sky and red rain in different | countries. Nov, Act. Nat. Cur, vol, 2. 1763, 9th Oct.—Red rain at Cleves, at Utrecht, &c. Tate Historico y Politico de Madrid, Oct.1764. | 1765, 14th Nov.—Red rain in Pieardy.. Richard. 1781, in Sicily —White dust not volcanic. Gioeni, Phit. Trans. vol. 72. oe, 27th, 28th, and 29th August without interruption —A shower of a substance resembling cinders in the town of Paz, in Peru. This henomenon could not be attributed to a volcano. Explosions were heard, ‘and the sky was observed to be illuminated. The dust occasioned great disorders in the head, and produced — in several persons. Mercurio Peruano, vol. 6; 792 1796, 8th March.—In Lusatia, after the fall of a ball of fire, a . viscous matter was found.* _ Gilbert’s Annals, vol. 565. 1803, 5th and 6th March, in Italy.—A fall of red dust, dry in some places ; in others moist. Opuscolz Scelti, vol. 22. 1811, in July, near Heidelberg.—Fall of a gelatinous substance, after the explosion of a luminous meteor. Gilbert’s Annals, vol. 66. 1813, 13th and. 14th March.—In Calabria, Tuseany, and Friuli. A great fall of red dust and red snow, with much noise. ‘There fell at the same time some stones at Cutro, in Calabria. Bzbl. Brit. Qo. 1813, and April, 1814. (Sementini found in the dust ; silica, 33; alumina, 151; lime, 114; iron, 1445; ehrome, 1; carbon, _ * Ihave a small portion which has the consistence, colour, and smell, of very dry brownish varnish. I believe it to be composed principally of sulphur and carbon, MM. Guyton—Morvean, and Blumenbach, also had portions of it. et M. Chiadii’s New Catalogue of Aerolites. 95 1M; ;loss:15., It appears: that Sementini did not bar lo lobk for-magnesia or nickel. i8i4, 3a and 4th July.—A great fall of black dust in Canada, >) | with amappearance of fire. The event was similar to that. of 472... Phil. Mag, vol 44... isl4, in thé night of the 27th and. 28th Oct,—In thie valley of ~Oneglia; near Genoa, red rain. Giornale di: Fisica, Bo. ah to amteliat lie aoe ¢ bc a0 Nov.—It: was found in the Doab, in Sa that every - store whieh fell, was surrounded by. a little heap. of .» o) dust. Phil. Mag. 1816, towards the end of) September, the sea to the south of - India was. covered with dust to a very great extent, «> probably after/a similar fall. Phil. Mag. July, 1816.: 1816, 15th April—Red snow in different places, in the northern oon) parts of Italy. series di Fisica, Re. vol. 1, 1818, banat 478), socitt 1819; ‘sth. Aug ant jie a in. \Momiadbants ‘Atter a Tesi ‘eovroey nous meteor, there. fell ans offensive gelatinous mass: acs . Silaman’s Journal; 2, 335. : 1819, 5th Sept.—At Studeiny:i in Mecoukvia bs in the jurisdiction of ie Teltsch, between eleven and. twelve o’clock at noon, the sky being serene and tranquil,.a shower of small és: ) pieces” of earth; proceeding from a small insulated ss 9) transparent cloud. Hesperus, Nov. 1819, and Gil. od bert’s Annals; vol.68. 1819, th Nov.—Red rain: in Flanders; andi in ‘Holland. Ann: Génér..des: Sciences Physiques. (Cobalt and muriatic om acid were foundin:this rain). | 1819); in’ Nov.—At Montreal, and in» the sinsctioekerth part ‘of the taut ‘States: Black rain: and show, accompanied Ldn an extraordinary darkness of the sky, concussions. ab an earthquake, detonations resembling discharges ans be fit artillery; and igneous flashes: which were ‘taken for “905 oc) intense hghtning.». Ann. de. Chim. vol.15.. Some oo 0. persons attributed the phenomenon to the conflagra- oo. tion of a forest, but. the noise, the concussions, Xc. »\ Sov prove thatit was really a meteor similar to those of aoe Sy A722, 1637,'1762, and 1814 (in Canada). It appears -moe seodhat the, biadk: and friable stones which fell at Alais, in «© 1806; were nearly the: same a ina state of hes reater aggregation. 1821, 3d ay, at nine .o’clock in 5 thes mornirign dRedm rain in the environs of Giessen. M. Professor Zimmerman having analyzed the reddish brown sediment left by this rain, found in it chrome, oxide of iron, silica, lime, carbon, a trace of magnesia, and some volatile particles ; but no nickel. 96 M. Chiadni’s New Catalogue of Aeroliles. ~ (Awe. 1824, 13th Aug.—City of Mendoza, in the republic of Buenos Ayres. Dust that fell from a black cloud. At a distance of 40 leagues, the same cloud discharged itself again. Gazette de Buenos Ayres, Nov. 1, 1824. M. Chladni has extracted from the work of Ma-Touan-Lin, a Chinese author of the 13th century, lately translated by M. Abel Remusat, merely the dates of those aérolites, fragments of which could be collected. If we suppose all globes of fire which are accompanied with loud explosions before they disap- pear, to be true aérolites; Ma-Touan-Lin would supply 96 additional instances. M. Remusat shows that the Chinese and Japanese observed with much accuracy every thing connected with the appearance of these yn ital phenomena. They re- marked that stones sometimes fall in perfectly calm weather ; they compared their detonations to thunder, to the noise of a falling wall, and. to the iy of oxen ; and the hissing noise which accompanies their fall to the rustling of the wings of wild birds, or the tearing of a piece of cloth. According to them the stones are always in a state of ignition at the moment they reach the ground; their external surface is black; and some of them sound when struck like. metallic substances. The name by which they called them signifies falling stars changed into stones. _ The Chinese believed that the appearance of aérolites was connected with passing events, and for that reason made cata- logues of them; I do not know that we have. much right to iaibails this prejudice: were the savans of Europe much wiser when, rejecting the evidence of facts, they affirmed that falls of stones from the atmosphere were impossible? Did not the Academy of Sciences, in 1769; declare that a stone, whose fragments were collected at the moment when it fell, near Lucé, by several persons who followed it with their. eyes to the point - where it reached the ground, did they not declare that it did not fall from the atmosphere ? Lastly, was not the attestation of the municipality of Lagrange de Juliac, affirming that on the 30th of August, 1790, a large quantity of stones fell in the fields, on the roofs of the houses, and in the streets of the village, treated by the contemporary journals as a ridiculous fable, catculated to excite the contempt, not only of savans, but.of all rational per- sons? Naturalists, who refuse to admit as facts, only those phe- nomena which they are able to account for, certainly do more injury to the advancement of science, than they who are liable to the imputation of being too credulous.— [$3 1826;] On the Quantity of Vapour in the Atmosphere, &c. 97 Artic.ie III. Methods of e erimentally determining the Quantity of Vapour in the Atmosphere, and the Specific Gravities of Gases mixed with ~ Vapour. By John Herapath, Esq. : - (To the Editors of the Annals of Philosophy.) .. 4, GENTLEMEN, - Cranford, July 18, 1826, In, the Annals of Philosophy for Nov. 1821, p, 375, &c, Lhave briefly explained the theory of two methods of determining the ‘quantity of vapour at any time in the atmosphere. One of these methods was invented by Mr. Dalton who, I have shown in the above cited pages, has, by some oversight, miscomputed the experimental results. Aware that simple and easy methods of ascertaining the relative and absolute quantities of vapour in the air are inmany researches of importance, especially as the sensibi- lity and accuracy of the common hygrometers are known s0 to vary as in a few years to become almost useless, I have thought it advisable to detail a little more methodically than I have the principles and application of the above methods, and to adda third which, I believe, is new. This last method hes the advan- tage of combining greater accuracy with more extensive utilit | : is | __ First, or Mr, Dalton’s Method, _ | » Let the water in a clean thin glass vessel be gradually cooled, either by pouring into it colder water, or by mixing mith it nitre, sal ammoniac, &c. until the vapour of the air begins to be deposited on the surface of the glass in the form of dew, which is just when the glass begins to appear dull. Let the tempera- ture of the water at this moment be noted ; and from Mr. Dalton’s experiments, or his theorem, or from that, one which I have given, Annals for Dec. 1821, p. 434, let there be taken the corresponding tension of the vapour, and it will be equal to the elastic force of the vapour in the air, Forsince the cold stratum at the surface uf the glass must haye the same elastic force as the air, and since, at the very commencement of the deposition, the proportions of air and vapour in this stratum are the same as in.any other part of the air, the ratio of these elasticities must be the same; and consequently the elastic force of the vapour in the stratum is the same as in other parts of the air. — Mr. Dalton, in order to get the elastic force of the vapour in the air, increases the before found tension in the ratio of 448 + the Fahr. temperature of the water to 448 + the temperature of the air, not considering that from the very principles of fluidity every part of the air, whether in contact with a colder body or not, must be pressed by the same force, and therefore have the New Series, vou. x11. 98 © 5 Mit Herapath on the Quantity of Vapour’) [Avé. same elasticity. Hence the vapour found by Mr. Dalton’s calculation always exceeds the quantity actually existing in the air. Suppose 7, be the tension just found, and .p the barometric pressure of the air, then p —. r, is evidently the elastic force due to the dry air; p — +, : r, is the ratio of the volumes of dry air T . " ‘ . and vapour; and — is the absolute volume of vapour in any unity of the compound mass of vapour and air, supposing the vapour could exist as an air under the pressure p. And if 7 denote the tension of vapour corresponding to the temperature of the air, the humidity of the air is “,absolute humidity being 1. Iff, fi be the Fahr. temperatures of the air and water, then the absolute volume of vapour by Mr. Dalton is eerie d the humidity of the air = oe The greater the difference I between f and f;, that is, the less the vapour in the air, the pret will be the proportional error of Mr. Dalton’s method. ff = 60° and f, = 40°, the error will amount to more than 4 per cent. © as ie “shea | t has been justly observed by M. Biot, that this method: of experimenting “ may not have in ordinary hands all the sensi- bility which its authoris pleased to attribute toit.” In such hands as Mr. Dalton’s, almost any method will succeed ; but certainly the above process, elegant and simple as it is, requires no ordi- nary care to insure success. I have often thought whether a vertical glass cylinder open at the top only, and successively dipped for short times in water or mercury of different tempera- tures; might not afford more uniform results, since the cold air i the cylinder being heavier than the air above, would keep its contact with the glass better than the air cooled on the outside of the glass vessel; but I have never brought this method to trial. . : ? ’M. Biot has also objected to Mr. Dalton’s method on the score of its not been applicable to small portions of gas; but a very trifling modification of this method, which no doubt has occurred to its author, will easily enable us to apply it to any portion of gas. For example, if a small lege? vessel furnished with a stop- cock or two, and filled with the gas ata given temperature f and pressure p as ascertained by a manometer, be immersed in a vessel of clear water which is gradually cooled down, the incipient dulness of the immersed glass might be easily seen, and thence the volume, &c. of the enclosed vapour be. deter- mined. Suppose the temperature of the water at this moment ig f, and the corresponding tension of vapour 7, then | . f +448 fore |" tree er ernae ve e () 1826.] inthe Atmosphere, and the Specific Gravity of Gases. 99 is plainly the absolute. force of the vapour at the temperature f when the whole pressure is p and ) f+448 | frig *'* a Oe ee is the elastic force of the enclosed gas. | If we put unity for the specific gravity of dry atmosphere at the Fahr. temperature 32° and barometric pressure 30, its specific gravity, it may be easily shown at any other temperature f, and pressure pis) | : btopedl l6p BOR, Frag totter te (3) | Putting therefore for p the absolute force of the vapour (1) just found, the specific gravity of the air becomes 16 ry ; F, +448? five-eighths of which, or S10 +, SF, +448? is, by Lussac’s observations, the specific gravity of the vapour confined with the gas. And if this be subtracted from the specific gravity ofthe mixture supposed to be already determined, it will leave the specific gravity of the gas at the temperature Ff and pressure (2). Second Method. Let ABCD be any rectangular glass tube A yn at A, and having stop-cocks at C, D, whose orifices are 6, a; and let the glass be attached to a board or any other thing in a vertical position. Having closed the cocks C, D, pour into A mercury of the same tem- perature as the air and tube, until the air enclosed in C D just begins to cloud the glass with the deposition of its vapour; and sup- pose at this moment 7, s, are the respective | surfaces of the mercury in the legs BA, CD ; and let the difference of their altitudes be m, oe the’ barometric: pressure being as before p. mn Then the elastic force of the air’ in Ds is to the elastic force of the atmosphere, or, which i is in the same proportion, the elastic force of the vapour wD s 1s to the elastic force of the de vapour in the air, asp + m : p. But the vapour in Ds just beginning to deposit itself, and being of the same temperature as the external air, must manifestly have an elastic force equal to the tension of vapour corresponding to the temperature of this-external air. That is, 7 being the tension H2 100 Mr. Herapath on the Quantity of Vapour _ {Ave. z eee ee ae i) (4) € ptm is the elasticity of the vapour in the atmosphere, and of course P ites were ee ee eer eeeeees (5) is the force of the dry air, Dividing the preceding by p, gives | ptm ‘a for the absolute volume of vapour in a unity of the atmosphere. And if instead of by p we divide by r, the result p ptm expresses the humidity of the air. he formulz in this method ought to give the same results as the corresponding of the preceding method, Equating therefore rs with ©, we shall find : t ptm the left hand member of which is the formula for the humidity of the air as given by the first method, and the right hand mem- ber the formula for the same thing given by the second method. In the same way we may deduce other expressions in either method, by only knowing its expression in the other method, and having given the equation —— = *. : m P This second method has a considerable advantage oyer the first, inasmuch as it is free from the uncertainty of the tenta- tive process. It may also be applies to almost any portion of any compound air however small. Another advantage is its not requiring attention to regularity in the caliber of any part of the tube, which may be regular or irregular in any degree. By opening the cock D, and allowing the mercury to force out the confined air, and then turning the cock C so as to let off the mercury to any extent, we may draw into C D a fresh ortion of air, and commence the experiment anew, It will, shore be advisable in this case not to allow the mereury to ascend quite to the top of C D, asit will be extremely difficult to see the incipient deposition whereyer the mercury has touched the glass, unless it be cleaned before re-commencing ; which may throw some doubts on the real temperature of the tube, a point of the utmost consequence to the success of the experi- ment. If instead of atmospheric air we experiment on a mixture of any gas and yapour at the temperature of the air f, and it be required to find the specific gravity of the gas; then replacing p ia (3) by (4) and taking five-eighths of the result from the prm 1826:] in the Atmosphehey and the Specific Gravity of Gases. 101 specific gravity of the mixture at the temperature and pressure of the atmosphere, leaves the specific gravity of the gas at the temperature f, and pressure (5). | These two methods bemg independent in principle and prac- tice, will, if made at the same time, afford’a mutual check and corroboration, As they both, however, rest in a great miea- sure on a certain delicacy of ocular observation, 1 shall now ~ explain a : Third Method free from those defects. | : is Having introduced any quantity of the atmosphere in DC of out rectangular tube, as well as some mercury in the other leg B A, close the cock D and open C, until the surface of the mers: cury in B A sinks as much as it can below the other surface in C A; so as however not to descend into the horizontal part B C. Then having shut C, measure the pressure on the enclosed mixture, which will be less than the barometric pressure by the difference of the altitudes of the mercury m € D and BA, and call it p. Let s also be the space occupied by the mixture, which, supposing C D perfectly cylindrical, may be represented by the depression of the mercury in CD, below the interior upper part of it D. At this time it is clear that all the vapour is in the airiform state, its elasticity being less than in the open: air. : This done, pour in some more mercury in A, until, from the dulness of the glass D s, we are certain that some of the vapour is condensed ; ‘and let the measured pressure and spacé occu- pied be p, and s,. a Repeat these admeasurements after having poured in as much moré mercury as you conveniently can; and suppose the new pressure and space are p, and s,. Let + be the tension of the vapour corresponding to the temperature of the air /, which, from thé well known laws of vapour, must be the same as the elastic force of the vapour in both of the last experiments. Then p, — 7 : p, — 7 :: elast. of gas in s, : elast. of gas in s, 7: § : 8. Therefore 2. Piss = Pa Se T= aie omg oceessocesesee (6) Consequently the elastic force of the gas in s, is prot =o sy edo evodes (7) s and in any other space s, it is Sy, (Po = Pi) Sr 82 | (7) Dae Fe ARES MPa But in s the whole pressure of all the vapour and ait is p, and therefore the pressure due to the vapour alone is 102. On the Quantity of Vapour in the Atmosphere, &e. [Ave. P SAS — $2) — $1 So (Pa — Px) , p— (8) = Er eeeeee (9) Mg il Hence supposing the vapour could exist as an air under the same pressure as air, vol. gas : vol. vapour ;: (8).: (9); and vol. gas + vol. vapour : vol. vapour :: (8) + (9) : (9). Therefore what we have constantly in the course of our inquiries called the absolute volume of vapour is equal to (9) Ld $a 8; Sq (p® — p,) rw! peGa ay tttrsteess (10) which a we had chosen might have been more concisely deduced | from (8). . er Again, putting s, for the space occupied by the mixture at the incipient state of condensation s,:s :: (9) : +, and : 8 (%; — 82) — 5, 8, (py — p, 8, = (9). Od I) The whole pressure at this time will consequently be ceil (py 8; — Po $2) p $ eg s, ps (51-8) ~ 8, 8, (Py — Pr) nes: (12) Dividing P + by this, P being the barometric pressure at the time of the experiment, gives the force of the vapour in the atmosphere equal to 1 | Pp 8 (8,82) — 8, 82 (Pa—pr) (o P. pss, — 8) " eee eters eoever sneuewsAty) and consequently, by what we have already shown, pss = 82) — 82 (po — ps) : ps (s; — 8) eeeseenven e*eeeene (14) is the absolute volume of the vapour in a unity of space suppos- ing it could exist as an air under the pressure P, at the temper- ay of the atmosphere. Again dividing (13) by (6), and we ave p s (3; — 81) — 8; 89 (po — py) Bs THIEL PH ohdlge anak teraind FIMAPD the humidity of the air, absolute moisture being unity. And if f be the temperature of the mixture, and we substitute (13) for p in (8) and take five-eighths of the result from the specific gra- vity of the mixture previously obtained, it will leaye the specific gravity of the enclosed gas of whatever kind it may be, when the temperature is f, and pressure P— (13). This method of making the experiment is independent of any knowledge of the tension of vapour, which indeed it brings out, and may be applied to determine. ‘The only things necessary to attend to are, the accuracy of the capacity of that part of the glass tube in which the mixed airs under examination is con- tained, and the temperature of this same part of the tube, which it is most essential should be exactly determined and not afterwards affected by handling or otherwise. A little change will also be. 1826:] Mr..Gray onthe Genus Hinnita of DeKrance,§é. 108 made by: the expansions ahd contractions of the air, and the: condensation of the. vapour; but if proper ;time be taken, the results perhaps will not be sensibly affected. Should they, however, it might be obviated by immersing this. part of the apparatus in a vessel of water of a known temperature. | robably a joint in the base BC. of the tube, enabling the leg A B to have.a vertical circular motion about it, would render’ the apparatus more practically convenient, by making the com= pression in C D, more gradual, and taking away the irregular impetus occasioned with pouring the mercury in at the orifice Av he greatest merit of this method is its being so complete _ within itself... It not only gives the tension of the vapour exclu- sive of any previous determination, and clears the results from the uncertainty of delicate ocuiar phenomena, but. it may be applied to almost any portions of any gases with the same ease and success as to the atmosphere. JoHN HERAPATH. ArtTIcLE IV. Ona recent: Species of the Genus Hinnita of De France, and. some Observations on the Shells. of the, Monomyaires, of La- marck. By J. E. Gray, Esq. FGS. (To the Editors of the Annals of Philosophy.) GENTLEMEN, British Museum, July 15, 1826. In the list of species of shells not taken notice of by Lamarck,. which was published inaformer number of the Annals of Philosophy, I described as a new species of thie genus Lima a shell, of which I had observed an old very much worn specimen, in the British. Museum ; having, since that period, observed two specimens of a fossil species, which agreed with all the characters that were peculiar to my Lima? gigantea, I therefore was inclined to con- - sider them as forming together a distinct genus, and I was farther’ confirmed in this opinion when I re-examined the other: allied genera, for | found, by the assistance that the fossil, specimens afforded me, that the recent shell was most probably attached (immediately), to the marine bodies, and that it was certainly much more nearly allied to the genus, Spondylus of Linneus, than to the genus which I had from the examination of the mutilated recent specimen referred it to. | Thinking that perhaps the fossil shells had been described, I compared the specimen with the characters and observations which De France has given for his genus /immnites, which he established for two species of fossil shells, and to which he - observes there are no recent species known. I) found that it agrees im every particular with his remarks, and therefore I feel » 104 Mr. Gray onthe Genus Hinnita of De France, &¢. Ave. myself perfectly satisfied that it may be considered as the recent wpe of that genus ; thus, at the same time, adding the génus, innita (for now the name must be changed, as the termination: ites is only used in those genera where the species have only hitherto been found in a fossil state), to the list of recent: shells, and erasing it from the catalogue of those genera which are considered by geologists as only to be found in a’ fossil state, | i" The following character may be given to the genus, which should be referred to the family Spondylide (nob.) wi Hinwira, nob. Hinnites De France. 1900 gal Shell bivalve, inequivalved, adherent immediately, by the apex: of the right valve. Valves eared, radiately striated; beaks slightly produced into a triangulararea. Byssal groove, noney - Hinge without teeth ; elastic cartilage placed in a deep groove,: in each valve ; ligament marginal, linear, straight. Animal unknown. ; The chief character by which this genus.is to be distinguished from Spondylus, is that the hinge is destitute of teeth, and that the facets of both valves are nearly équally extended by the rowth of the shell; instead of the attached one being extended mto along shelving projection, as in the latter, and that the valves are more equal and more distinctly radiately ribbed, and not quite so spinose as most of the species of the latter genus. De France, in the work above quoted, has described two fossil species, 1 H. Cortesyi, figured in the Dictionaire des Sciences Naturelle, t. 61, id 1, and 2, H. Duboissoni, to which I now add as the recent type, _ 3. A. Gigantea. Shell oblong, outside pale brown, finely radiately-grooved, inside white, hinge margin purple. Lima gigantea. Gray, Annal. Phil. Icon. Wood, Catalogue Suppl. t. 2, f. 7, imedited. Inhabits. Mus, Brit. Shell oblong, rather thick, solid, outside pale brown, orna- mented with numerous small rays, the left valve the most con~ vex, the inside white with the hinge margin fine dark purple, the area left by the moving forward of the ligament 1s also purple, andrather narrow, the grooves for the elastic cartilage is very large and distinct in each of the valves, and quite open, they are extended the whole length of the facet, and consider- ably produced into the cavity of the shell. The muscular. impressions are large, and the submarginal impression is. orbi- cular ovate, with a considerable inflexion just even with the anterior ear. The length is four inches, the height from hinge to basal edge five inches. | I shall here take the opportunity, as I neglected it in my con- chological essays, of pointing out how the back and the front 1826.]| Mr. Gray on the Genus Hinnita of De France, &c. 105 edge, and consequently the right and left valves may be distin- guished in those shells which are provided with only one adductor muscle. Indeed, I only need to speak of those mono- myaires' of Lamarck, which have the elastic ligament placed in am internal cavity, as the others m8 be easily distinguished by the position of their external cartilage, as pointed out in my former remarks: In the whole of these shells, the adductor muscle, and consequently the muscular impression is placed eccentrically, except in the genera Anomia and Placuna. Now by examining the animals, figures of which may be seen in’ the appendix to Lister, who has given the anatomy’ of the oyster and scallop, and the plates of Poli models, the mouth will be found to be always torte on the opposite edge, and the anus on the same edge of the shell as the adductor muscles, consequently that edge of the shell to which the muscular impression is hearest, must be its posterior edge, and now if the hinder margin of the shell be placed towards the observer with the hinge edge uppermost, the sides of the animal and shell will correspond with that of the observer. Ihave been thus particular in pointing out this distinction of the valves of these shells, because the observance of this fact: will materially assist the natural disposition of the micropodous bivalves, and enable them to be separated into natural families, a division which is now absolutely requisite from the number of genera being so much increased by the great attention which has lately been paid to this interesting study. The animals of this groupe, which are attached to the rocks, &c. by a byssus, as the Pectens, have always the groove for the transmission of the byssus, placed under the ear of the right valve; this character at once distinguishes the Pectinide, a family which contains the genera Pecten, Anusium, Janira, Neithea, Pallium, Pedum, and Lima. Amongst those genera which are attached to the rocks by the means of the outer sur- face of the shell themselves, which appear to be the typical groupe of micropodous mollusca, the oysters are always fast- ened by the left valves, and the genera Ostrea and Gryphea may therefore form a family under the name of Ostreidie, while the Spondylide, which contain the genera Spondylus, Hinnita and Plicatula, are always attached to the marine bodies by their | right valves, and consequently the muscular impressions are placed on the right side of the attached valve, which makes the impression of Hinnita to appear to be placed on the side of the shell opposite to that of the oyster, as described by De France, who appears not to have observed that the difference was only occasioned as in what is erroneously called the reversed chama; by the animals being fastened by the other valve. The fact of the conical univalves being considerably altered in form and figure by the substances to which they are attached, 106 Ma, Christie on the Magnetism of tron. [AWE! has long ago attracted the attention of conchologists, and it) also has been observed greatly to influence the form of the: Anomie, for when they are attached to pectens and other: radiated shells, they are marked by their sculpture ; but I am: not aware that this fact has ever been observed to take place in any of the other genera of bivalve shells, and especially in those which are thick and ponderous.. The specimen of Hin- nita gigantea, which is in the museum, has evidently been: attached to a rock which had some large serpulee growing on it, the edges of the valves, when growing, conformed: them-. selves to the surface, and consequently the upper valve has the convex lines across, which exactly correspond with the convo- lutions on the outer surface of the lower one; now at first: sight one might, be led to believe, as indeed several of my friends have: been, that the convexity of the under valve, by pressing up the body of the animal, has consequently raised the upper surface of that part of the body, but in several places the upper valve is marked externally where there are no traces of it in the inner surface of either valve, nor are the upper. valves. of oysters affected when the lower valves have very large pearls on them, which must considerably displace the body of the animals. | Indeed, to any one who studies the formation of shells, 1. think it must be evident that these raised places must be’ formed as I have stated, by the edge of the upper valves con-: forming themselves when deposited to the bend of the lower valves ; and when the causes which produced these curves are removed, the valves resume the usual form, leaving the convex line on the outside, the concavities of the inner part of the upper’ valve being obliterated by the new layers of shell. wee ARTICLE VY. Abstracts of Papers in the Philosuphical Transactions for 1825, on the peculiar Magnetic Effect induced in Iron, and on the Magnetism. manifested in other Metals, &c. during the Act o Rotation, By Messrs. Barlow, Christie, Babbage, and_ Herschel. 2. On the Magnetism of Iron meh = from its Rotation. : By 8. H. Christie, Esq. MA. FRS. | | (Continued from p. 43.) rtoey « Experiments with the Dipping Needle. : “Having found, in all the experiments which I have de- scribed, that the effects produced on the horizontal needle» depended on the situation of the plate with respect to the axis” and equator of an imaginary dipping needle passing through 1826.] arising from its Rotation. 107° the centre of the horizontal needle, my next experiments were undertaken with the view of ascertaining whether the effects produced by the rotation of the plate on the dipping needle itself corresponded with those which I had observed on the horizontal needle. .In making these it was necessary to adjust the dipping needle on a staad detached:from the instrument, on the arm of which the iron plate revolved, on account of the diameter of the case of the dipping needle being greater than the distance sm (fig. 1.) It was therefore only in particular positions that I could observe the deviation caused by the rotation of the plate. This, however, was of the less importance, since, as I expected that. the deviations of the dipping needle would be less than those of the horizontal needle nearly in the ratio of sin. 19° 30’ to 1, it was only in the cases in which they were the greatest that I was likely to have been able to observe them. ; “As the dipping needle, when in the position of the dip, could only vibrate in the plane of the meridian, no effect. corresponding to the deviations,of the horizontal needle could: be observed, either when the centre of the plate was in the intersection of the meridian and equator, and its plane perpendicular to the planes of these circles, or when the centre of the plate was in the secondary to the meridian and equator, and its plane in the » plane of this secondary. In order, therefore, to ascertain the deyiations of a needle suspended freely by its centre of gravity, corresponding to those of an horizontal needle, when the plate had those positions, and which I considered to be the principal points to be determined, it was necessary to observe the effect. produced on ‘the dipping needle when the centre of the plate was in the equator, and exactly east or west of the centre of the needle, and its plane parallel to the plane of vibration of the needle; and also when its centre and plane were in the plane of vibration. “In making these observations, the instrument was adjusted as in fig. 1, the compass being however removed; the indexes at 0, 0’ were brought to Ad, «, on the moveable limb, and that limb was placed at right angles to the fixed limb, so that. the plane of the plate was parallel to-the magnetic meridian. The dipping needle was then placed as nearly as possible in the required position, and the levels being carefully adjusted, the needle was made to vibrate freely and left to settle. After the plate had been made to revolve several times in the same di- rection, the point. marked 0 was brought to coincide with the upper part of a line parallel to the magnetic axis, and passing through the centre of the plate. The needle was then slightly agitated, or made to vibrate through a small arc; and when it settled, the dip was noted both at the upper and lower ex- tremity, or the south and north end of the needle. This was 108 Mr. Christie on the Magnetism of Iron (Ave. | repeated for the points marked 60, 120, 180, 240, 300. The plate was now made to revolve in the contrary direction, and similar observations made of the dip of the needle when the several points 300, 240, 180, 120, 60, 0, coimeided with the upper part of the line parallel to the magnetic axis. Continuing the revolution of the plate in this direction, a second set of observations of the dip were made’ for the several points from 300 to 0. After this, the plate was again made to revolve in its first direction, and a second set of observations made of the dip for the points from 0 to 300. I considered the mean of all the’ observations in the two sets, when the plate revolved from 0 to 300, as the mean dip when the plate revolved in this direction ; the mean of all the observations in the two sets, when the plate revolved from 300 to 0, as the mean dip when the plate revolved in this: direction ; and the difference between these mean dips as the deviation due to the rotation of the plate. : gael “As I had experienced that the dipping needle, even when of the best construction, was an instrument from which accurate results could only be obtained by taking a mean of a great number of observations, I was aware that, by making only two for each point of the plate, I was liable to an error in the obser- vations for each point taken separately, but this I considered. would be counteracted in taking the mean for all the points; so that the mean results could not err far from the truth. The dipping needle which I made use of was a very good instrument, by ones, of Charing Cross: the needle, made according to ptain Kater’s construction, consisted of two arcs of a circle; its length was 7 inches. The plate was the same I had used in the experiments with the horizontal needle. PYRG “ For the better distinguishing of the edges of the plate and the direction of its rotation, 1 conceive two planes at right angles to each other to pass through its centre ; one, the plane of the equator or a plane parallel to it, which I call the equa- torial plane; the other, the plane of the secondary to the equator and meridian, or a plane parallel to this secondary, which I call the plane of or parallel to the axis. ‘The inter- sections of the first plane with the edges of the plate, 1 call the equatorial north and south edges ; and the intersections of the second, the polar north and south edges. . “ From the observations thus made it appears that, in this posi- tion of the plate, the deviation of the upper, or south end of the needle, due to rotation, was in the direction im which the north or lower edge of the plate revolved, and the deviation of the north or lower end of the needle, in the direction of the rotation of the upper or south edge of the plate. It would follow from this, that if a needle could be suspended freely by ifs centre of vity, and the centre of the plate were in longitude 90°, atitude 0°, and its plane at right angles to the meridian; 1826.] > arising from its Rotation. 109 then. also, the deviation of the sowth end of the needle due to rotation, would be in the direction of the north or lower edge of the plate, and the deviation of the north end, in the direction in which the south or upper edge revolved ; which are precisely the directions of the deviations of the horizontal needle in this position of the plate. . The law which I have shown to obtain in all the experiments on the horizontal needle, viz. that the sides of the equator of the imaginary dipping needle always deviated in directions contrary to those in which the corresponding edges of the plate moved, I had derived previously to having an opportunity of making any experiments with the dipping needle ; a comparison of the above results with this law will more fully illustrate its nature, and at. the same time show their perfect accordance. In making this comparison, it 1s necessary to notice that, an increase of the dip of the needle, corresponds to a deviation of the southern edge of its equator towards the south pole, and of the northern edge towards the north pole ; and on the contrary, a diminution of the dip corresponds to a deviation of the southern edge of the equator towards the north pole, and of the north- ern edge towards the south pole. Now, when the equatorial south edge of the plate revolved towards the polar sowth, and conse- quently the equatorial north edge towards the polar north, the inclination of the needle was diminished by the rotation; that is, the south edge of its equator deviated towards the north pole, and the north edge of its equator towards the south pole; or the edges of the equator, by the rotation of the plate, deviated n directions contrary to those in which the edges of the plate moved. The same conclusion evidently follows from the. observations when the equatorial south edge of the plate revolved towards - the polar north, the dip being here increased by the rotation of the plate. | | \ The next observations which I made, were of the inclinations of the dipping needle, when the plane of the plate was in the plane of the meridian or plane of vibration of the dipping needle. © From these observations it appears that, the plane of the plate being in the plane of vibration of the needle, and its centre in the equator, the deviation of the upper or south end of the needle, due to rotation, was in the direction of the rota- tion of the upper or south edge of the plate, and of the north end in that of the north edge; and we may therefore conclude, that if a needle could be freely suspended by its centre of gravity, and the centre of the plate were in the equator, and its plane in that of the secondary to the meridian and equator, the deviation of the south end, due to rotation, would be in the direction in which the south edge of the plate revolved, and of the north end, in that in which the north edge revolved ; which, again, are precisely the directions in which we have seen, that 110 Mr. Christie on the Magnetism of Iron [Ave. the horizontal needle deviated by the rotation of the plate in this position. , “* When the centre of the plate was in latitude 90° south, contrary to what took’ place when it was in the equator, tlie deviation of the south end of the needle is in the direction m which the dower or north edge of the plate revolved; and we may therefore infer that the same would be the case if a needle were suspended freely by its centre of gravity, and the plane of the plate were in the plane of the secondary to the meridian and equator, its centre being in latitude 90° S: which also agrees exactly with the directions of the deviation of the hori- zontal needle, due to rotation, in this position of the plate. “It is evident from these different experiments with the dipping needle, that whatever may be the peculiar effects produced on the iron by its rotation, the deviations of the horizontal needle, due to the ratation, are. of the same nature as those that would arise by referring the deviations of the dipping needle to the horizontal plane. Theoretical Investigations. o “ It has in general been considered that the different deviations of the horizontal needle, arising from the action of soft iron on it in different positions, can only be accounted for on the sup- eee that the iron is polarized by position, the upper part eing a north pole, and the lower a south one, each pole of the iron attracting the polé of the needle of the same name, and repelling that of a contrary name: but if we suppose that each particle of the iron simply attracts indifferently either pole of a magnetic particle, and refer the attraction of the iron to its centre, then if the angular deviations of a magnetic particle in the centre of the needle and in the line of the dip, arising from such at- traction, be reduced to the horizontal plane, these reduced deviations will agree with the actual deviations of the horizontal needle. In investigating theoretically the effects that are pro- duced by the rotation of a plate of iron, I will first suppose, that, independently of rotation, the iron acts in this manner, and that by the rotation it becomes polarized in a direction, making a certain angle with the magnetic axis, since from such a rag of the iron,, the law which I have shown to include all the phenomena, would evidently result. On this suppo- sition, each pole of a magnetic particle in the centre of the needle would be urged by an attractive force towards the centre of the iron plate, by an attractive force towards the pole of a contrary name, and by a repulsive force from the pole of the same name in the iron.” Mr. Christie here proceeds to investigate this theory by calcula- tion, the results of which, he finds, “indicate that the effects are not produced in precisely the manner we have supposed.. In one 18262] i \) arising from its Rotation,» ©. 11 ‘point our theory: is: unquestionably ‘at’ variance with the) actual circumstances of the case; for we have supposed that no partial magnetism exists in the iron, or that every part of it taken separately would equally affect the needle. It is, I believe, scarcely are to procure iron that shall possess this uni- formity of action, and it is evident that this was not the case with the plate of iron which I made use of. This species of -polarity in iron is of so variable: a nature, since by an acc ‘dental. blow it will be transferred from one point to another, that it does not appear possible in any manner to submit) its effects to calculation. It was to prevent these effects embar- rassing the results, that 1 took the mean of twelve observations for each position of the plate; still it is possible that some of the differences between the observations and the results of the theory may have arisen from this cause. | “ As the results of the hypothesis which I have advanced do not precisely agree with the observations, it will be proper to enquire whether we shall obtain a more: perfect agreement’ by means of the hypothesis commonly assumed, in order to account for the effects produced on the needle by a mass of soft iron, viz. that the. upper part of every mass of iron acts as a north pole and the lower part as a-south pole. Let us then suppose such poles to exist inthe iron’ plate, in the diameter m the direction of the dip, and that the rotation causes the line joining them to describe in the iron an angle } from this diameter.”’ The agreement between the. observations and the calculated results from this. theory, Mr. Christie here finds, would not be greater than in the former case. nif “In the explanation of the phenomena which take place:on presenting the different ends of a mass of iron to the poles of a magnetic needle, in addition to the hypothesis, that the upper part becomes.a north, and the lower a south pole, by position, it is necessary to suppose also, that in every change of position of the: iron there is a corresponding and immediate change of its pole; that. is; the upper end becoming the lower, it also immediately becomes a south pole. Now it appears to me, that if we attempt to: explain, on this hypothesis, the. pheno- mena arising from the rotation of the iron, we shall find that there are circumstances which are wholly incompatible’ with it. If on turning a mass of iron end for end, the poles are imme- diately transferred from one end to the other, how can we sup- pose that the revolution of the iron will cause these poles to move forwards, so that the line joining them shall describe an angle from the line of the dip? or even granting that during the revolution of the iron they may be carried forward, they must, as soon as the-iron ceases to revolve, resume their original po- sition in the line of the dip, if they are so immediately trans- ferred from one end of the iron to the other, as it is necessary 112 Mr. Christie on the Magnetism of Iron (Awe. to suppose in order to account. for the phenomena which take place of attraction and repulsion, as they have been called. mediately, then, that the iron becomes stationary in any position, the deviation of the needle ought, on this hypothesis, to become the same, whether the iron has been brought into that position by revolving in one direction, or in the contrary. It is hardly necessary for me to say that this would not be the ease, since I have stated, that, in all the preceding observa- tions, the iron was stationary previous to the observation being made, 7 “ Whatever are the effects produced on the iron by its revo- lution, so far from these effects being of the transient nature which we must suppose them to be on this hypothesis, they appear to have been quite permanent, that is, so long as the iron remained in the same position. .The following observa- tion will show the small changes which took place during 12 hours. ) “In order that the needle might be quite free to move, it was suspended in a balance of torsion by.a brass wire, of the same diameter as the finest gold wire used for transits, free from torsion, 21.15 inches long. The plane of the plate was in the lane of the secondary to the equator and meridian, its. centre an latitude 0°, longitude 180°; and it was fixed to. a wooden axis passing through its centre perpendicular to its plane: the ends of this axis, which revolved with the plate, being made: of brass, that I might ascertain whether the effect was independ- ent of friction on the plate itself. The plate was made to revolve in contrary directions, as usual, and the direction of the north end of the needle noted, when the pomt 180° on the plate coincided with the upper part of a plane parallel to the meri- dian, and passing through the plate’s centre. After haying made the plate revolve so that its upper edge moved from west to east, and noted the direction of the north end of the needle when 180° coincided with the above plane, it was made to revolve from east to west, and 180° being again brought to coincide with this plane, the direction of the north end of the needle was noted at different times for more than 12 hours, the plate remaining stationary during that time. > 1826.) arising from tts Rotation. 113 Direction of ro- . Time of ! tationof plate’s| W to E'| E to W jobserva- upper edge. tion. 2 / h g5m GE ge S dct “4 os be me 7} During this time the plate was kept per- 59 o anit cle fectly stationary, and care was taken ‘s $ s 9 i 4 190 3h that the apparatus should not be in the : | @ 49 |o1 48 : least spl oo : s 1bg) fter 21 48,, the plate was made to re- s 7 © 0 02 E 22 Ol volve slowly once from W to E. S 9 5 0 025 99 17 After making the plate revolve several ¢ & times and more rapidly. ad Making the plate revolve several times 2 : Big ne Makin, the W revolve wane so slowly 5 : = Be « i . bt a2 40 that the time of rotation was 3’ 26”. r 83s 24 05 | § The plate kept perfectly stationary since Ba 8. dys gsi 25 35] 2 22%.40™. | 8 es sD Making the plate revolve through 30° Ey? 1 22 from W to E, and then bringing it See back 30° from Eto W. "s 2 3 d Making the plate revolve through 90° vs wa 2 42 from W to E, and then bringing it z g tt ‘E back 90° from E to W. 2 ES & 2 42 acai the plate revolve repeatedly and > rapidly. _. “From these investigations it appears, that the effect produced on the iron by its rotation is permanent, so long as the plate remains stationary : that it is independent of friction ; that it is so far independent of velocity, that the iron can scarcely be moved so slowly that the whole effect shall not. be produced ; and that the whole effect is produced by making it perform only one fourth of a revolution. : , Shortly after I had discovered these peculiar effects to be produced y the rotation. of iron, 1 poimted out the general nature of the phenomena, and exhibited some of them to -Mr. Barlow, and he has since made some experiments on the rotation of spherical shells, in which he has found that pheno- mena somewhat analogous. take place, but they appear to be dependent on the velocity with which the shell is made to Tevolye.” : | i ie oe galt “‘ Since it appears, from all the observations which I have detailed, that the direction of the magnetic polarity, which iron acquires by rotation about an axis, whether it be at right angles to the line of the dip, as would follow from the theory which I have investigated, or not, has always reference to the direction of the terrestrial magnetic forces, we must infer that this mag- netism is communicated to it from the earth. It does not therefore appear from this, that a body can become polarized by rotation alone, independently of the action of another body: so that if from these experiments we might be led to attribute the magnetic polarity of the earth to its rotation, we must at New Series, vou. X11. I 114 Mr. Christie on the Magnetism'of Iron {Ave. the same time suppose a source from which magnetic. influence is derived. Is it not then possible that thé sui may be the centre of such influence, as well as the source of light and heat, and that by their rotation the earth and other planets may receive polarity from it? If so, farther experiments and ob- servations on the magnetic effects produced by the rotation of bodies may indiéate the cause of the situations of the earth’s —_ poles, and of their progressive moyements or oscil- ations. - Comparison of the magnetical effects produced by slow ond. | by rapid rotation. eat « With the view of ascertaining how far the éffects produced on a magnetic needle by a plate of iron during its rapid rotation, corresponded with those that I have described as nearly inde- endent of the velocity of rotation, and as continuing after the rotation had ceased, I placed the same plate of iron, which I ‘bad used in my former experiments, in the plane of the magnetic meridian, on an axis perpendicular to its plane, and about which it could be made to revolve with any velocity, not ex- ceeding 10 revolutions in a second. I then placed a small compass, with a light needle delicately suspended, on a plat- form wholly detached from the iron plate, in certain Hout ith opposite to the edge of the plate, both to the east and to the west of it, as near to the surface as the compass box would admit. The compass being adjusted, the plate was made t revolve once, slowly, so that its upper edge moved from north to south, and the point 0 coinciding with the plane petpendi- cular to the plane of the plate, and passing through its centre and that of the needle, the direction of the north end of the needle was observed; and also when 180 ‘coincided with the plane, the same observation was made, The plate was now made to revolve rapidly in the same direction, about 8 ‘times in @ second; and when the needle became pein | : ‘during the rotation, the direction of its north end was observed. The point 0 on the plate was again made to coincide as quickly after the rapid rotation as possible, and the direction of the neédle observed, in order to see if that rotation had produced any permanent change in the iron; the same was done when the point 180 again coincided. Observations precisely similar to these were made when the upper edge of the plate revolved from south to north. 2 whip “ Although the centre of the plate was stationary, and the néedle was placed in certain positions with respect to it, | con- sider, as before, the situation of the centre of the plate with reference to the plane passing through the céntre of the needle perpendicular to the dip; and its angular distance fiom this 1826.] arising from its Rotation. 115 plané, the équator, was measured on & circle of 9 inches radius parallel to the meridian, passing through the centre of the needle, and at the distance 1-45 inch from it, so that the centre of the needle was always at this distance from the edge of the plate, east or west. As the needle was only two inches in length, and the rim of the compass divided into degrees, the direction of the needle could not be observed nearer than to 5’, and indeed scarcely to that degree of accuracy. The mode which I was under thenecessity of adopting in adjusting the compass to the several positions did not admit of extreme accu- racy, so that these positions may be considered as liable to errors amounting to 1°, or perhaps rather more, in angular dis- tance from the equator; but as my principal object was the comparison of the deviation due to the slow and rapid rotation of the plate, when its centre was in precisely the same position with respect to that of the needle, this was not very material ; it will however account for any disagreements that may be noticed in the absolute deviations in corresponding. positions, as the greatest accuracy of adjustment would be requisite for their perfect'agreement, when the plate is so near to the poles of the needle. i “Having ascertained, by the observations when the plate was to the west of the needle, that the rapid rotation produced no permanent change in the iron beyond that arising from the slow rotation, the deviations when any particular points of the plate were opposite, to the needle being, as near as could be expected, the same after the rapid rotation as they were after the slow rotation in the first instance, the errors being some- times in excess, sometimes in defect, I did not repeat the obser- vations on the effects of the slow rotation after the rapid, when the plate was to the east of the needle.” From the inspection of the tables containing these observations, “it appears that the forces which are exerted on the needle during the rapid rotation of the plate, are always in the same direction as the forces which are derived from the slowest rotation, and which continue to act after the rotation has ceased; but that the former forces are greater than the latter, there being only one instance of the contrary, and that in a position where the effects are so small, that’ a trifling error of observation would account for the difference. Taking a mean of all the obser- vations, these forces appear to be in the ratio of 19 to 13, or very nearly 3to 2. It is evident then that the polarising of the iron in the same direction will account for the phenomena in both cases, but that the intensity of the polarity during the rapid rotation is greater than of that which appears to be per- manent after the rotation, whether slow or rapid, has ceased ; ys 12 AS 116 M. Berzelius’s Analysis of some Minerals. fAve. and that the phenomena observed during rapid rotation are such as we should expect ftom those which I have so fully described as arising from rotation, without regard to its velocity,” | f. w. B. (To be continued.) ArTIcLe VI, Analysis of some Minerals. By Mons. J. Berzelius.¥ Phosphate of Yttria. THis mineral was found by M. Tank, in the neighbourhood of Lindenas, in Norway, in a gangue, chiefly consisting of large grained granite, and accompanied by another mineral, which, both by its external characters and those which it pre- sents before the blowpipe, perfectly resembles the orthite dis- covered a year ago, at Skeppsholmen. The specimen of phdsiplite of yttria, sent to M. Berzelius, was too small to admit of a perfect mineralogical description of the mineral ; its form was irregular, with crystalline strie, like those observed on imperfectly developed garnets. ' Its colour is brownish veltev, similar to that of the zircon, from Fredrikswarns, with which, at first sight, it might easily be confounded. Its specific gravity at 60°=4°5577 ; it is scratched by steel. Its fracture is foliated in several directions ; its trans- verse fracture is uneven, and splintery ; externally it is dull, but the foliated fracture has a resinous lustre, and the transverse a ae one. In thin fragments it is semi-transparent and yel- owish. Before the blowpipe this mineral behaves much like phos- phate of lime. Alone it does not fuse, but its colour becomes deeper. Heated in a matrass, it gives off no water; with borax it dissolves slowly, and forms a éolowiess glass, which becomes milk-white by flaming, and, if saturated, whitens on cooling. It dissolves with great difficulty in salt of phosphorus, and forms a transparent colourless glass. This mineral differs from phos hate of lime by the facility with which the latter dissolves the salt of phosphorus, forming, if the salt be saturated, a glass which loses its transparency on cooling. The same, how- ever, would happen with the phosphate of yttria, but the opera- tion requires great time and labour. With carbonate of soda, the assay produces a strong effervescence, and gives an infu- sible, clear grey scoria. ith boracie acid it dissolves with difficulty ; but if a morsel of iron be introdaced into the glo- * Extracted from the Annales de Chimie. 1826.} § M. Berzelius’s Analysis of some Minerals, 117 bule, phosphate of iron is formed in abundance. ‘The acids, even when concentrated, do not dissolve it. The analysis of phosphate of yttria gave : Yttria eereoeeoeeeeoeeveree eo eeoen er ervreoeeevee 0 e 62:58 Phosphoric acid, with a little fluoric acid... 33°49 Subphosphate of iron. ...eeseeseseeeeee 398 100-00 The formula of the composition of this mineral is therefore analogous to that of phosphate of lime, Y° P*. As, hitherto, no other native combination of yttria with phosphoric acid has been discovered, it seems ‘superfluous to give this any other denomination than that of phosphate of yttria. | Polyinignite. A black, brilliant, mineral, crystallized in small prisms, is sometimes found in the zircon-sienite of Fredrikswarns, whose very complicated composition has indaced M. Berzelius to call it polymignite, (modus et wry.) It is black, and absolutely opaque, even on the edge; the mattix, nearest in contact with it, is usually of a red colour, as ‘occurs at Finbo, with albite, if it contain yttrotantalite. This mineral is always more or less regularly crystallized in long thin prisms, with a rectangular base, whose edges are usually replaced by one or more planes ; sometimes two of the planes of the prism are broader than the rest ; its length is from one to four lines. Berzelius never had an opportunity of seeing the extremities of the prism sufficiently developed, to enable him to determine the form with any precision. e The specific gravity of polymignite = 4°806. It scratches glass, and cannot be scratched by steel. Its fracture is con- choidal, without any indication of cleavage. The surface of the crystals has a bright, almost metallic lustre, to which that of the fracture also approaches, and far exceeds what is commonly ob- served in minerals. Its powder is brown, the colour becoming clearer by trituration. | rs ‘It undergoes no change before the blowpipe, neither fusing, nor losing its lustre ; it givés off no water. With borax it fuses easily, and gives a glass, coloured by iron; if more borax be added, the glass becomes opaque by flaming, and acquires an ‘orange colour; with a still larger quantity it becomes opaque on cooling. If the mineral be fused with tin, the colour becomes red, inclining to yellow. It dissolves also ‘in salt of phosphorus, ‘but with less facility ; in the reducing flame the glass assumes a ‘reddish colour, which is not altered by the addition of tin; in _ the oxidating flame-the reddish colour becomes clearer, and in- 11s M. Berzelius’s Analysis of some Minerals, [Ave, clines slightly to yellow. With carbonate of soda, the assa decomposes without fusing, and the mass becomes greyish red, A larger quantity of the salt gives an imperfect scoria. If we add borax to the assay, we obtain some traces of reduction, but it is commonly manifested only by metallic strie, when tri- turated in the mortar. The analysis of polymignite gave Titanic acid eeeeeeeeeereeeeseeeeees 46:3 COON eas 's caus s sins cs 0a} ian hee O CTRWIe OF SEG.) knee Race be tebe och oh iam Lime <5 OU «a psih tans alah aligies bab aid 4:2 . Oxide of manganese ...escecverers. Sto. Oxide OF 'CETIOM - indigo. wininnad d4+ Seinen MEET IR sn 0 een! Onis nite ln dincalest ik tana aaa 115 poems ») a PRR otassa ; Silica ee eevee re pveoesegeore traces of | Oxide of tinJ Loss e@e4aeoeev ee eeaeeveeenee eevee ee eene 3:7 | 1000 _ The real loss is still greater than that given above, for the iron and manganese, and perhaps also the cerium, exist in the mineral in the state of oxidules, whereas, in the results, they are taken as oxides, The analysis of so complicated a mineral must always be attended with very considerable loss, and it ma even contain some substances that have escaped detection, It is evident, therefore, that the composition of a mineral like the polymignite cannot be calculated. ete “ T have often attempted,” adds M. Berzelius, ‘‘ to separate titanic acid and zirconia from each other, but have not been able to discover an infallible method for the purpose. Diluted sulphuric acid separates them best, but it sill, dingalves a small portion of titanic acid, as well as the zirconia. The carbonated alkalies dissolve them alike, and nearly in the same proportions. Sulphate of potash, which often does not precipitate titanium from its solutions, throws it down, however, if they contain zir- conia, which, in that case, carries down the titanic acid. Fluoric acid acts nearly in the same manner. Infusion of galls precipi- tates both titanic acid and zirconia, The analysis of polymignite might be effected with sufficient accuracy, if we had a method of separating these two substances; but it also contains two others. which cannot be separated; namely, yttria, oxidulous manganese, the latter of which, in certain proportion, adheres obstinately to the former. The best mode of separating them that I know, is to dissolve them in nitric acid, evaporate the — solution to dryness, and keep the salts for a long time at the 1826,), M. Berzelius's Analysis of some Minerals. 119 temperature of melting tin; after which dissolve out the nitrate of yttria by water. If the quantity of water be small, the solu- tion will not contain any: manganese; but when we wash the oxide of manganese, a portion dissolves, and the solution as- sumes a dark colour, which it loses by exposure to light.” — Levyine. : _M, Berzelius found a specimen of levyine, (sent him from a quarter that precluded all suspicion of error,) so extremely simi- lar.to his mesoline, a mineral which accompanies the tessellite from Ferroe, that he was desirous of ascertaining its exact com- position. The texture of the mimeral was. crystalline, and wherever the angles could be measured, they were found to, cor- respond with those of chabasie. hee | -Its analysis gave him, — a ~ Silica ........ 48:00, containing oxygen. .24:06 i Alumina. ecwe 20:00, CVS C CK CO COO TKO O OOS 34 ime set... oe _ Magnesia .... . 0°40 Potassa..i.... .0°4) i Soda ‘y eaeece, 2°73 Water eee ve 19:30. ‘ eeee eine eeeoveecose 1716 fas | 99-21 Nb “ This result,” M. Berzelius observes, “ accords perfectly with the proportions of the component parts of chabasie,” namely, | Ka ae j | | Ts Sara a aR Be 3:25. C our? , i Nhs 4 3.A8t 40 Aq 4 o y K ‘ | . as may be more distinctly seen by the following table: Thatasie Soui\Chaladpic! feoia| Chabagia’ fommb «igs 4: 5 Ferroe,*’ “| Scotland, | Gustafeberg..|. *csoine: Wilieedibecseaiesssc.4. 4890,.} - 49°17 50°63. | AT Alumina. eeeeveveseteor 19°28 : 18-90 17-90 21°4 g Lime rr « w ° 8°70 _— 9°73 : 7:9 Soda. eee- nce a) = 12:19 a 4:8 r PORE. 05 6dis ions veers ‘ 2:50 a, ‘ 1°70 besa; Water Seerees C88 ee . 20°00 : 19-73 19°50 18°19 B Bee Fiskeal dy 98-18 99-99 99-48 99°79 | “With respect to the chabasies, I consider it certain,” adds _ Berzelius, “ that the trifling differences which occur in these analyses are occasioned by their not having been perfectly freed from the minerals which accompany them; hence mesoline ought to be considered merely as a species of chabasie, as is further observable in its granular texture.” ~ * Analysed by Arfiedson. 120 On Excessive Heat in America [Auc. ArticLe VII, : Notices of the Excessive Heat nots some. Parts of the. late, ‘Summer (1825.)* 1, Observations on the Heat, &c. at Brooklyn, New York, for the month of July, 1825. The thermometrical observations exhibit the lowest temperature in the morning and evening, and - the highest during the day. The lowest are from a thermometer always out of doors; the highest from one in an open hall, where no ten or reflection can have effect. Communicated by ‘the Rey. Dr. 8S. Woodhull. ; . | — - 1825, , Usually at six Usually at half-past two July. Mouing. 3 o’clock. O'clock, ine oe ofp anally mf AG, p.m. 1 |73. Clear. SW. 89, Clear. NW. 71. Clear. NW. 2 |12. Clear. W. 91. Cloudy. SE, °° (8. Cloudy. | SE. 3 71. Cloudy. SW. Driz-'77, Cloudy, E. Rain; |73. Clear. ; lin Ar. Set 4 |t4. Clear. W. 87. Clear. W. 175. Clear. SW. 5 |76. Clear. S. 89. Cloudy. S. Rain, {71, Cloudy. SW. 6 |67. Clear. NW. 87: Clear.. NW. ~~ ‘|74.°Cloudy. S. 7 |70, Clear. SW. 85. Clear, N., 73, Clear. N. 8 (67, Clear. NW. 89. Clear. S. . 19. Clear. NW. 9 |69. Cloudy. NE. 87. Clear. E. 68. Cloudy. E, 10 |75. Clear. NW. 93. Clear. W. 86. Clear. W. 11 |79, Clear. W. 94. Clear, W. 87. Clear. SW. 12 |79. Clear. WSW. 94, Clear. W. 88. Clear. SSW. 1 13 |76. Clear. NW. 89. Clear. WNW. 81. Clear. NW. 14 |72. Cloudy. N. 85. Clear, SE. 79, Clear. SE, Light , rain, 15 |71. Clear. SW. 82. Clear. S. 72. Clear.. SSE. 16 |70. Clear. WNW. 85. Clear. 8S. 74. Clear. SSW. 17/72. C NW... 89. Clear. SSW. 178. Clear, calm, 18 |74. Clear. NW. 194, Clear. SW. 80, Clear. S. 19 =|77T. Clear. W. 92. Clear, SSW. 82. Clear. SW. 20 |77. Clear. SW. 94. Clear. SW. 85. Clear, SSW. 21 |79. Clear. SW.. 96. Clear. SW. 86. Clear. SW. 22 (80. Clear. W. 95. Clear. W. 84. Clear. S. Light- ning and thunder. 23 78. Clear. W. 97. Clear. SSW. 79. Clear. SW. (same.) 24 |74, Clear. SW. 93. Clear. SW. 80. Clear. W. 25 {77. Cloudy, calm, rain,|79. Cloudy. NW. 73. Clear. SW. a.m, » see 26° |69. Clear. N. 84. Clear. SW. 73. Clear. NW. ‘22 «167. Clear. NE. 86, Clear. SW. 68. Clear. SSE. 28 |67. Clear. NNE. 87, Clear. ENE. Tl. Clear. SSE. 29 |68, Clear. NE. 85. Clear. S. 70, Clear, SSE. 30 |68. Clear. SSW. 81. Clear. S. . 74, Clear. 8S. 31 |74. Cloudy. S, 90. Clear. S. Light rain|76, Cloudy. NW. . in the afternoon, Average nearly 90°. * Extracted from the American Journal of Science. 1826.]: during the Summer of 1826. 121 2. Temperature at Williams College during the late excessively hot weather. | MY Ya dh e, 1825, am! p.m. {p.m. Mean. | Wind. July 10|72-0| 92:3 |81-1| 81-80|. NW |At 33 p.m. temp, 93:3. 311800} 96-8. |77-0| 84°60); S_ jAt2s p.m. temp. 97-0 Sunset 98°5 12/75°7| 93-6 {74°6| 81°30| NW |Thundershower at evening. _ 19/665); 91-5 |78-4| 78:80) NW 20\75°5| 95:1 (76:3) 82°30} S 21\74°7| 95:3 175°0| 81°67} S_ |Some rain at sunset. 22\78°2| +928 Lape 83°07; S 23/76°5| - 98°0 |83°6| 86:03) S [Some rain. Temp. 98°5 at 3 p.m. 24/740) 87-4 |74°5) 18°63) NW average 193-5 nearly The mean temperature of the month is 74-95, which is a little less than that of July, 1820. The temperature was at no time. in that year so high as that given above. The mean temperature of the month of July for the last nine years is 69°61, and for the last ten years including this July, is only’70°14. This shows the excessive heat of the late month of July. . There were some hot days in June, but the temperature was not above 96° in the hottest part of the day. ‘The thermometer is suspended six feet from the ground on the north side of a house, exposed to a free circulation of the air, but protected from all reflected heat. i ae 22. Observed three spots upon the sun—two large and black. | Note.—After these tables, follow some extracts from United States newspapers, from which it appears, that in some days in the course of the same month (July, 1825), the thermometer ranged at Hartford, in Connecticut, from 96° to 102° in the. shade; at Salem, Massachusetts, it reached 104°; at a village in Yates’ County, N. Y. 106°; at Wiscasset, Maine, 107°; and in a multitude of other places, the temperature was nearly as high about the same period. An, article dated New York, July 25, says, ‘The thermometer, we believe, for the last two days, has scarcely varied during the day, from 95° in the shade, and the mercury has not fallen much in the night season. The ravages of death, yesterday, were truly melancholy. Twenty- five inquests were held upon the bodies of persons who came to their death by means of the heat, or by drinking cold water ; and there have been several cases to-day—some before eight o'clock this morning. It seems to do no good for the press to admonish the public upon this subject; and those who return from the burial of friends, with a strange fatality, drink and die ina few minutes afterwards. So true is it that ‘all men think al mortal but themselves.’ , 122 (On Excessive Heat in America in 1825. [Aue.: We observe this morning that the civil authorities are put-. tine cautions upon the pumps, printed in large letters.” . ~~ We have ourselves seen ‘similar laudable cautions affixed to the pumps in Philadelphia, with, we fear, no better success. To” this we must add some further ae a the American news- apers (quoted in the American Journal of Science). respecting acm gaye © of last winter, 1825-6.. | tad [att it The Portland (Maine) Argus states, that the last day of January and first day of February were the coldest days expe- rienced within the memory of the present generation. The’ mercury fell to:24° below zero. At Bath on'the same days the mercury was at. 27, and at Brunswick 29° below zero...» The Virginia papers state that the present winter has been the coldest for several seasons. On the Ist of February, at Peters- burgh, the mercury ranged several degrees below the freezing oint. | Rg oe. | : 5. A man was frozen to death in Montreal on the night of the 31st ult. which was the coldest day experienced for years. Many ersons had their faces frozen while walking through the streets. 1ermometer 32° below the freezing point. Ovss 20088 29 In Boston, ey gue’ Salem, &c. the thermometer stood from 12 to 17° below 0. . The Boston papers state, that a woman was frozen to death in Southac-street on Tuesday night; and a stage coachman on the line between Groton and Concord, was found frozen stiff upon his box on the road, holding the reins in his hand. He was dead, and the reins were clenthed so fast, that they were obliged to be cut, before they could be extricated from his grasp. | , Bods _ At Montreal, Lower Canada, on the 31st. of January, the mercury fell to 38° before 0. | | ~ At Keene, New Hampshire, it was 28° below zero. _ — The newspapers ‘from every quarter, make mention of the severity of the cold on the night of the 31st January and morn- ing of the Ist February.— Ed. aie! Articie VIII. Remarks on the Rev. Mr. Powell’s Paper on Radiant Heat. By William Ritchie, AM. Rector of Tain Academy. (To the Editors of the Annals of Philosophy.) GENTLEMEN, Paris, July 20, 1826. Havine observed in the 67th number of the Annals of Philo- sophy, a paper by the Rev. Mr. Powell, in which he calls in question the truth of some of my experiments and deductions on the properties of radiant heat, published in the Edinburgh 1826,.] Rev. Mr. Ritchie's Reply tothe Rev. Mr. Powell. 123 Philosophical Journal, I consider myself bound, in justice to the cause of science, to answer his objections. This will be best accomplished by a single deduction from the following ; Experiment, — | att . Let two air thermometers be procured having their bulbs large, and blown extremely thin (this condition is absolutely necessary to the success of the experiment) with scales divided into any number of equal parts. - Place these at a convenient distance, from each other, and then place a heated iron ball between them in such a.position that the fluids in the two stems will sink exactly the same number of degrees. Let one of the hemispheres in the ball A, formed by a plane passing through the centres of the two balls, be coated with china ink. Let two of the alternate quarters of the ball B, formed bya plane cutting the former at right angles, be also coated with china ink. Place the thermometers’ in their original position, raise the iron ball to an elevated temperature, (though still invisible in the dark), place it in its former position, and carefully observe the number of degrees the fluid descends in each stem, A striking differ- ence will now be observed. The fluid will be found to have sunk several degrees lower in the thermometer B than in A. The same experiment may also be performed with a differential thermometer, having the bulbs coated as formerly described, » Whatever be the cause of this striking difference, it cannot pos- sibly be the one assigned by Mr. Powell. For the surfaces of the two balls having exactly the same quantity of coating must. radiate the absorbed heat with equal rapidity. I have viewed the subject in every way I could think of, and can find no cause adequate to produce this striking difference, except the one which I formerly assigned; viz. that the portion of caloric which radiated freely through the transparent hemisphere in one of the balls, was interrupted by the opposite posterior coating on the other ball. ee : - With regard to the experiments with coated and transparent screens, I would only remark that a common mercurial thermo- meter is quite inadequate to determine the fact. If a quantity of water at the temperature of 50° be mixed with a hundred times - its bulk of water heated to the temperature of 501°, the common thermometer will not detect the difference. In like manner, if the quantity of heat which freely permeates a thin plate of glass, amount only, in peculiar circumstances, to ~1, or 1, of a degree of Fahrenheit’s ‘thermometer, the common mercurial _ thermometer can not possibly determine its existence. I would, therefore, humbly recommend to Mr. Powell to procure screens of extreme tenuity, and repeat the experiments with a more deli- cate instrument. than a common thermometer, and. he will assuredly find that the results which I have stated are not hasty 124 Statement of a Plan for fAuc. conjectures but absolute facts. I might also mention that M. Arago informs me, that he has performed numerous experi- ments with transparent screens, and has uniformly arrived at the same results. I may further state, that 1 have performed various experiments with transparent screens of different kinds, and have, without a single exception, arrived at the important conclu- sion,—that a portion of ca/oric from an elevated source, though invisible in the dark, freely permeates a thin transparent screen in the same manner as i hi instantaneously finds a passage through thick plates of glass. These experiments and deduc- tions will form the subject of a paper which I intend to lay before the Royal Society at one of its earliest meetings, in which I shall endeavour to establish on a solid foundation the striking connection between light and heat discovered by the ingenious French philosopher De la Roche. ARTICLE IX. Statement of a Plan for making aminute Survey of the Heavens, and for the Formation and Piablication of some New Celestial Charts, under the Superintendence and Direction of the Royal Academy of Sciences at Berlin.* ° _. [Tux Council of the Astronomical Society are happy in being able to lay before the members, a plan which has been sug- gested for a minute survey of the heavens ;—a prang deside- ratum in modern astronomy ;—and, in fact, one of the principal objects for which this Society was originally established, and which it has constantly laboured to promote. | __ The plan, here alluded to, appears to have originated with M. Bessel, who has himself observed upwards of 32,000 of the smaller stars, situated between 15° north and 15° south decli- nation. With a view to render the survey of this zone of 30° more perfect (so as to comprehend many other stars not yet observed by him or by any preceding astronomer), it is proposed that it should be divided into 24 equal parts; each part con- taining’ 1" in AR. And that every person, who is disposed to take a share in the undertaking, should devote himself to a minute examination of all the stars situated in that portion of the heavens which may be allotted to him:—1°. by reducing to the ear 1800 all the stars hitherto observed in that district ; and aying them down on a chart of given dimensions :—2°. by in- serting also on the same chart, from estimation by the eye, or from actual observation with an instrument, all the remaining _® This statement has been printed by the Astronomical Society of London for circula- mn among the members ; and as the plan cannot be made too public, we reprint it,— 1826.} making w minute Survey of the Heavens. 125° stars (to the 9th and 10th magnitude) that have escaped the observation of preceding astronomers. Pg In order to prevent any confusion in the distribution of these portions of the heavens, it has been thought proper that the whole plan should be placed under the superintendence and di- rection of the Royal Academy of Sciences at Berlin: and they -have accordingly issued a Prospectus, giving a detail of the plan proposed. A copy of that Prospectus was forwarded to the Astronomical Society: but some of the parts requiring ex- planation, Mr. Herschel was requested to obtain further infor- mation on those points which appeared to be ambiguous. In reply thereto, M. Encke (the Secretary to the Academy) has addressed a letter to Mr. Herschel, which more fully and clearly developes the views of the Academy. oe Translations of the prospectus and of the letter above alluded to are subjoined. hie the Council of the Astronomical Society trust that, in thus giving publicity to the plan proposed, and circulating it amongst the members, it will be needless to add any arguments in favor of a proposal, which promises, much more fairly than any other that has yet been suggested, to ac- complish so important a desideratum in modern astronomy. ] The modern celestial charts, by Flamsteed, Bode, and Har- ding, contain only those fixed stars whose places at the time of their publication were astronomically determined. The number of these, however, has gradually increased from 3000, (marked in Flamsteed’s catalogue and the atlas founded on it,) to nearly 50,000 as given in the Histoire Céleste and in Piazzi’s catalogue ; the whole of which are marked in Harding’s charts. Never- theless, these celestial charts are very far from containing all the stars visible by means of the telescope; the number of which Seems to be immense, or to increase without limit with the in- ereased power of this instrument. Indeed we can never expect to obtain charts that are absolutely perfect; and if we aim at any degree of accuracy, it can only refer to the assumed limit of the magnitude or brightness of the stars. Before the discovery of ‘telescopes such a limit was fixed by the power of the eye, and the charts were capable of FOR INE a certain degree of perfection founded upon it. Flamsteed, however, although he added many new stars, remained far be- hind the perfection attainable even in his time: and it was pro- bably the immensity of the number of the stars which pre- vented this great astronomer and his successors from attempting to perfect their charts beyond a certain limit, and induced them to remain contented with noticing only those stars that were astronomically determined; leaving many others unnoticed, which, although of equal brilliancy, had not yet been con- sidered. 2 3 : Nevertheless it is desirable that we should possess charts & 126 Statement of a Plan for [Ave. that may be perfect to a certain limit; and the more desirable the further this limit be removed. If we determine that limit by the smallest stars yet visible through one of°Fraunhofer’s comet-seekers of 34 lines aperture and a magnifying’ power of }0 times, (and which can be observed without difficulty by Reichenbach and Ertel’s meridian circles, provided with Fraun- hofer’s telescopes of four inches aperture, in an illuminated field,) we shall seldom or never find a deficiency in the astrono- mical application of the charts, and shall obtain a result, the surpassing of which would not only be extremely difficult, but would be prejudicial for obtaining a general view, owing to the excessive number of stars which it would be necessary to intro- duce. But this detail being once attained, the charts will show us at once any thing new, on comparing any part of them with the heavens, provided the magnitude of the star be not less than the limit assumed. Besides the interest naturally attached to 4 more correct view of the heavens generally, and the faeility thereby obtained for many astronomical observations, sue charts would also offer the surest means of enlarging our know- ledge of the solar system, by the discovery of new planets. Nay, such a result will be highly probable, whilst without such special celestial charts they can only be found by some lucky chance. . Indeed, there have been repeated attempts towards construct« ing charts of this description: and although they have not been crowned with success, it will be sufficient to enumerate the causes that have impeded their execution, in order to show that they are not now insuperable. The perfection of the celestial charts to a certain limit can only be attained by first laying down on a net work,* or scale, those stars that have been determined by meridional observations, in order that all the rest, intended _ to be introduced, may be added from estimation by the eye, per+ haps assisted too by some instrument. By meridional observa+ tions alone, even if repeated more than once, we cannot acquire the certainty of having all the stars within the assumed limit. Even the Histoire Céleste contains much fewer stars than are necessary.as a basis for perfect charts; wherefore it was néces- sary to make de novo, a more numerous series of meridional ob- servations. Such a one has now been made at'the observatory of Konigsberg, extending over a circular zone of the heavens from —15° to+15° declination, and containing about 32,000 ~ stars; which, according to an experiment made in a part of the * [This net work is delineated on the copper-plate engraving which accompanied the original communication, and which was sent as a pattern. It consists of 100 small squares, formed of faint lines, half an inch (Eng.) asunder ; each square Seg p rey a degree. It is formed on the plan, and on the same scale, as Harding’s Atlas; at therefore it is unnecessary to give a specimen of it here. The plate itself is given in Schumacher’s Astron, Nach, No, 88; and it may be seen by application to the Secre- tary of the Astronomical Secietyee Sec. | , 1826.} making a minute Survey of the'Heavens. ~ 127 heavens most filled with stars, are quite sufficient. Besides this difficulty, now removed in a zone of 30° of declination, there is another, viz. the perfecting of the charts by the eye, which is so laborious and requires so much time, that a single individual can make but little progress init. This may, however, be removed by the co-operation of several ; and the active zeal now preva- lent among astronomers allows us to indulge in the hope that many will assist in promoting so great and useful an under- taking. = , igunbee i it is therefore the wish of the Academy of Sciences to unite for this object the friends of astronomy; and to procure for them every possible facility. It invites all astronomers to assist in filling up the 24 sheets of a complete celestial atlas, for which the foundation has already been laid; viz. from — 15° to +. 15° of declination and the 24 hours of right ascension: laying down at the same time the following rules to be observed in the execution. , 1°. The net work, or scale, to consist of squares for the de- grees of declination and right ascension: each degree mea- suring 58 Parisian lines (or 0°51 English inch). It should ‘extend from 4 minutes of time before the beginning of an hour, to 4 minutes of time after its termination: and thus contain 510 squares. 2°. In this net work are to be marked the stars observed at Palermo, Paris, and Konigsberg, reduced to the beginning of the year 1800.* , 3°. The largest of them should be marked after the manner of the pattern sheet attached to the present plan: those stars which are visible only through a telescope, by larger and smaller aeek rings ; and those visible by the naked eye, by the addition of rays.f . 4o" If a star has been observed but once, the same should be marked by a short faint line projecting from one side of it; if twice, or more frequently, by two such lines, one on each side of it.{ For stars visible to the naked eye, this kind of desig- nation would lead to indistinctness, and is in fact needless, . since they are all described in Piazzi’s catalogue ; and therefore show, by their rays, that they have already been observed. 5°. The sheets, in this state must be compared with the heavens: and all the stars, within the limits proposed for the intended sheet, must be estimated by the eye, as correctly as * [Thestars observed at Palermo are given in Piazzi’s Catalogue: those observed at Paris are given in the Histoire Céleste: and those observed at Konigsberg are given in M. Bessel’s Observations.—Sec. ] : + [These marks are similar to those adopted by Mr. Harding in his charts. The eet mode of delineating the different magnitudes may be seen in the pattern sheet.— ec. | . i! [For specimens of this mode of distinguishing the different stars, see the pattern sheet, alluded to in the note in page 126,—Sec. ] 128 | Statement ofa Planfor {Ave. possible, and be inserted therein. And it must be, observed that the stars of the chart must be such as can be seen under favourable circumstances with one of’ Fraunhofer’s comet- seekers of 34 lines aperture, and a magnifying power of 10 times. 1 _ 6°. When stars stand too closely together to be separated in the drawing, their magnitude only need be delineated, and the ‘number of them indicated by an equal number of lines under- neath it, as in the pattern sheet, 19" 29™ and + 11° 56’. Where two stars are found double stars, i. e. such as are not above 15” or 20” distant from each other, they should be dis- tinguished by such distance being mentioned: ex. gr. at 19" 52™ and + 10° 12’.* | 7°. The sheet thus far advanced must be frequently compared with the heavens, partly for the purpose of discovering the changes that may have occurred during the drawing, and partly also for the purpose of finally fixing the magnitudes which the observer may be disposed to give to the stars. _ It will perhaps not be possible to notice in the drawing the minute distinctions between the magnitudes of the smaller stars marked on the pattern sheet, such as the 9th and (9.10th) magnitude, nor will it be essentially necessary, One may be convinced by the pattern sheet (which represents one of the most starry parts of the heavens), that it is pos- sible to attend to all these rules :} and that the great multitude of stars, marked upon it in the manner they are represented, neither crowd the space, nor render a general review difficult. ‘To name and describe in such charts either the constellations and their limits, or single stars, would be both useless and in- . Jurious. | The Academy have appointed a committee, consisting of Messrs. Ideler, Oltmanns, Dirksen, Encke, and Professor Bessel of Konigsberg. And whoever is disposed to undertake the execution of a sheet, should apply to any one of the members of that committee, who will point out to him a portion not yet undertaken by others. Such a district will remain open for him during two years: and if, after that period, he cannot show to the committee that he has made some c®hsiderable progress in it, it will be transferred to another. Lait __ As soon as any sheet is completed it must be sent to the com- mittee ; who, after having examined and approved of it, will cause it to be engraved and published, without waiting for any others. The name of the author will be engraved on it, and * [For specimens of this mode of distinguishing the different stars, see the pattern sheet, alluded to in the note in page 126.—Sec. ] . + [The greatest number of stars in any one of the squares in the pattern sheet is i 6, and they are all perfectly distinct, even with the distinguishing marks attached to em.—Sec. } 1826.) making 4 minute Survey of the Heavens. 129 any observations that he may have had an opportunity of making,—such as errors of the pen, or of the press, in lists-of observations,—on stars observed, but’ no longer existing,—on variable stars, &c. &c.—will be published in the Memoirs of the ‘Academy. _ The Academy entertain no doubt that the fact of being able to promote, without any expensive apparatus, such a great and useful undertaking, as well as the prospect of discovering new planets even during the construction of the charts, will be suffi- cient to excite the friends of astronomy to participate in it. Nevertheless, it has been thought proper to announce a reward of 25 Dutch ducats for the author of every chart made according: to the plan. As the Academy enjoy the privilege of free postage within the limits of the Prussian post, astronomers in addressing the members of the committee, or in sending in their charts, _may take advantage of this circumstance. , Berlin, 1st November, 1825. Letter from M. Encke, to J. F. W. Herschel, Esq. . . Berlin, May. 19, 1826. I hasten to answer the letter of the 29th April which you were so good.asto send me. ‘I set too great a value on the in- terest which the Astronomical Society takes in our plan, to delay for a moment giving you all the explanation that you wish for. _ The principal object of the Academy is to procure a know- ledge of the heavens as perfect as the present instruments will enable us to obtain. If in Flamsteed’s time we might content ourselves with possessing maps of all the stars as far as the fifth | and sixth magnitude, it appears that at the present period we ‘cannot even limit them to those of the seventh and eighth mag- nitude, but ought to extend them, so as to include in the: same sheet all the stars of the ninth magnitude. Or at least, the con- _tinual use we make of such stars renders it desirable to possess observations sufficiently correct of all the stars as far as the _ninth magnitude inclusive. If we wish to observe such stars in the same manner as Lalande has done in his Histoire Céleste,.or Bessel in his Zones, we could never be certain of having ob- served them all, their number being too great. It seems, then, that we should first of all endeavour to procure a knowledge of the whole of the above-mentioned existing stars, more detailed than that which can be obtained by an instrument fixed in the meridian. Afterwards we may propose to make on each of those stars the necessary observations, in order to assign more accurately its true place. . of Such then is the object of the new astronomical maps. They New Series, vou. x11. ale 130 Statement of a Plan for | [Ave. are intended as a guide to future astronomers, whereby they may know, at one view, whether there exists a star that has neyer yet been observed. In this point of view these new maps cannot by any means render superfluous the Atlas already Pe lished by M. Harding, which contains all the necessary details to be able to distinguish exactly in what place of the heavens a comet or a new star is seen. But the different objects of these two maps require also a different arrangement. M. Harding has taken his stars from the Histoire Céleste and from other cata- logues, and in the regions where the observations were not sufficiently numerous, he has made up the deficiency as well by his own observations as by drawings. We wish that, in the new maps, only those stars already observed should be noted, (viz. with one or two dashes,) which are found in books that are in the hands of every astronomer; and in order not to increase uselessly their number, we i ose to limit those books to the following ones; 1°. The Catalogue of Bradley (Bessel Fund. Ast.) 2°. Piazzi’s Catalogue (Palermo 1814); 3°. The Histoire Céleste of Lalande; 4°. Bessel’s Zones. If a star shall be found in any two of these books we may be certain that it is a fixed star; if it is found in one only, it may be a planet ora moving star. It is therefore. necessary that every one who wishes to take a part in this plan should also take upon himself to reduce, to the same epoch, the observations of the Histoire Céleste and of M. Bessel’s Zones, in order to be able to decide whether a star is either the same, or has only been affected by a ' very remarkable. proper motion. Fortunately this reduction waite found neither difficult nor long, by means of the Tables of Reduction that M. Schumacher has caused to be computed for the Histoire Céleste,* and by the help of those Tables that M. Bessel has adjoined to his Zones. { have no hesitation to assert, by my own experience, that I should be able in eight days to compute all the necessary reductions for a whole hour in AR: and that at the utmost 15 days would be sufficient for angry case. . Bessel’s tables of reduction give the formula (1825) AR st + hh’ =D) x -01 (1825) Deel. = 4+ d4+d’'(o— D) x °01 For example, Bessel gives for the 135th zone, the first of the riinth book, | k’ d d’ 4> 0 +0”288 + 0060) | —56”30 a a 30 0,225 68| + 0,062||—61,03 4,13 [3 a3 Pre whence, we have for the first five stars, * (Sammlung von Hiilfstafeln. Vol. ii,-Sec.] 1826.) making a minute Survey of the Heavens. 131 ,$+D §-D t Mi Stay AR for 1825. 17 3» 54m 28543 +0530 —O0301 3" 54™ 28°72 eee ) 56 6,60 +0,30 +003 56 6,93 +2 56 45,02 +0,29 0,00 56 45,31 —i6 57 28,00 +0,29 —0,01 5T 28,28 a, 2 58 44,20 +0,29 —0,01 58. 44,48 s—D , 3 d PRoae , for 1825, d ri Dec. for 1825 +79 43! 15/2 —55’44. ~062 +79 42 19/1 8 44 6,3 —55,70 +1,62 8 43 19,2 8 1 51,9 —55,79 +0,07. 8 O 56,2 7 43 38,2 —55,91 =0,59 7 42 42,9 7 50 32,0 —56,10 +0,38 7 49 35,6 Now itis only required to subtract the precession from 1800 to 1825, which can be done by a small table with double entry; which any one may compute for himself. For the stars in the Histoire Céleste M. Schumacher’s tablés will in the same manner enable us to reduce the observations at once to the epoch of 1800; so that it will not even be necessary in this case to compute the precession. _T-hope, Sir, that these reductions which require only the addi« tion of three numbers, will not appear to you either too long or too complicated. They comprehend at the same time all the corrections of the instrument, and of the apparent place ; and a computer ever so little versed in such calculations will not find the application of it troublesome or tedious. The degree of aceuracy is as great as may be attained by any other means ; since nothing indeed has been neglected in it.* _ Itis the desire of the Academy that each astronomer should himself make these reductions, and that he should then place these observed stars on his chart; distinguishing (in the manner above mentioned) those which have been once or twice observed. This part of the work is in my opinion a great deal more diffi- cult, and requires a more scrupulous attention than the compu ’ tation, where the two columns of the values of k and d follow a regular order, and the other two columns, k’ and d’, have never much influence on the result. Each sheet will represent two thousand observed stars at least; every one of which will have its mode of delineation prescribed according to its magnitude and the number of observations, It will not be possible to commit this operation, which cannot even bé easily verified, to any other person than the astronomer himself ; who, by putting his name to the sheet, will render himself responsible for the accu- .* [For the convenience and accommodation of those persons who are disposed to take . a share in this undertaking, the Astronomical Society have caused skeleton forms to be printed, by means of which much of the trouble and risk of etror attending the reduc- tions will be saved. Any number of these forms may be had, by application to the ee before the Ist of January next, after which day the press will be broken up.— ec. K 2 132 Statement of a Plan for _ [Aue: racy of his work. It is highly probable that many errors, both of observation and of writing, will be made amongst that immense mass of stars‘which are observed only once. If the astronomer himself makes both the reduction and the drawing, he will be able-to find out the cause of such errors more easily than ifthe whole were computed and arranged by another hand.- In fact, the execution itself of the drawing will render the person who undertakes it so well acquainted with the region he describes, that it will very much facilitate to him the accomplishment of the remaining part of the work, which consists in noting down the stars (down to the 9th and 10th magnitude) not yet observed. I think that the reduction and ‘the drawing of the stars already observed (made in such a manner that one may be certain that eacli star in the heavens corresponds to its place on the chart, which can only be obtained by making a revision of the heavens), is about half of the whole work, ahd that this is also the part a has the greatest influence upon the general accuracy of the’ whole. | _ These are the principal motives which have induced the Academy to propose the, plan in the manner they have done in the Prospectus. The Academy could not, as a body, itself undertake so extensive a work, and thereby render itself in some measure responsible for its accuracy. These: maps will form part of the Memoirs that are published by the Society. Each member will be answerable for his own portion, and the duty of the Academy can’ only be that of committing this work to per- sons who have already given proof of their being able to fulfil the task which they engage to undertake. It is on this account _ that you will find, in the Prospectus, that the Academy have determined that the name of each author shall be put om his map. This is the best proof that they do not mean to render themselves responsible for the correctness of the maps, as‘far as the authors are concerned ; but that they intend only to defray the expenses,—to encourage astronomers by prizes,—to pay attention that a perfect conformity be kept up among the observers, to ascertain that every one who takes part in it, intends to accomplish the proposed. object,—and lastly to super- intend the engraving of the maps. ae8 0 | | The Academy had eissstsived: this project before my coming to this situation; but their arrangements appear to me so proper, that J cannot add any thing to them to insure more fully the approbation of astronomers. 1 hope indeed, besides’ the ‘prin- cipal object, that the discovery of comets or even of some planet, and the opportunity that it will afford to many astronomers of acquiring a more complete knowledge of a portion of the hea- vens, will be some of the valuable results of this undertaking. On this account it has met with considerable approbation. » The greatest part of the districts are ready for distribution, and the 1826.] . making a minute Survey of the Heavens. 133 whole will probably be finished by the time assigned by the Academy for completing. the work, viz. the lst January, 1829. I ought to apologize if I have been too prolix, and I hope ou will ascribe it to the desire I have to insure also the appro- bation. of the Astronomical, Society. I.am much flattered that . you should have entertained the same opinion with me, as to supplying astronomers with sheets already prepared ;—a method which, if it could be executed, would certainly be preferable. On my first coming here, .and on being made acquainted with the views of the, Academy, I thought. it right to propose this idea to my fellow academicians ; but-having made trial’of the time -necessary for the execution of such a plan, I have been induced to alter my opinion. M. Harding’s maps,—a work ‘whose merit is perhaps not sufficiently known,—embrace nearly the half of the stars that have been. at present observed ; or perhaps about one-third: nevertheless they have occupied this industrious astronomer almost twenty years. Taking into the account that part of the heavens which is not comprised between — 15° and + 15°, I believe that 10 or 12 years would ‘elapse before one person, or even two co-operating for the same purpose, would be able to finish both the drawing and the engraving-of the maps. My present employment does not allow me to-apply exclusively to it, even if I had the confidence, -which certainly 1 have not, that every thing would succeed well. The undertaking would in such case be put off so long that per- haps. we could never be certain of finishing it. By dividing this work, however, into hours, we may hope that the honour and character of each astronomer that may take a share in it, will induce him to carry his own portion to the greatest possible degree of perfection. And.if the uniformity in the drawings should not be so great as if a single person had carried on the whole, yet we shall gainin point of time: and likewise have the advantage of making’ a revision of all that part of the heavens in the course of two years,—a period very little longer than that. which. would be required to execute a fine engraving of the mapse! isihoPes iwipagh. Ar beh ti No. 93 of the Astronomische Nachrichien published by M. -Schamacher, there is a-description of a machine which M. de Steinheil-has tried and found very convenient and correct for marking the precise place ofan observed star. If all the astronomers would make use of it, it would produce results having a great degree of conformity-amongst the whole. - . +. L remain, dear Sir, with the greatest consideration, ~ arte Yours, Xc. J.F, Encke, i 134 Analyses of Books, . | [Auc. | ArticLE X. ANALYSES oF Books. Philosophical Transactions of the Royal Society of London, for 3 1826. Bid I, tee if oe A f | , (Continued from p. 60.) III, Observations on the Changes which have taken Place in some ancient Alloys of Copper; by John Dayy, MD. FRS.: in a Letter to Sir H, Davy, BRS. | __ An abstract of this paper will be found in the Annals for Dec. 1825, p. 465. | | IV, Additional Proofs of Animal Heat being influenced by the Nerves: by Sir E. Home, Bart. VPRS, | V. The Croonian Lecture.—On the Structure of a Muscular Fibre from which is derived its Elongation and Contraction ; by the same Author The following extracts contain the substance of this lecture : _ “As far back as the year 1818, while considering the mode in which coagulated blood is rendered vascular, I brought for- ward a magnified drawing of a muscular fibre made i Mr. Bauer, showing it to be composed of a single row of globules tw parks of an inch in diameter, or, in other words, of red globules deprived of their colouring matter.” “ In this former examination of muscular structure, that the integrant fibre might be more easily separated from the fasciculus to which it belonged, we had gone into the same error with those physiologists who have made diagrams of the internal appearance of the brain, after coagulation, and had boiled the muscle previous to the examination ; not being aware that this process must decompose red globules, should any exist, and cause the colouring matter to be separated. . Boiling would also destroy any connecting medium by which the globules are united together; so that, if [ may use the expression, there would only be the skeleton of a muscular fibre remaining ‘to be examined. ' | | “Upon the present occasion, therefore, the fibres belonging to the fasciculi that compose the great muscle that lies upon the back of the bullock’s neck, to raise the head, were selected, and were examined in 24 hours after the animal was killed ; and we know that in all violent deaths, the muscular fibres continue capable of contraction beyond that period, after apparent death has taken place. | i | “In this muscle the fasciculi are more loosely connected together than in almost any other animal body ; and in the inter- stices between them there is no fat; but Mr. Bauer found that ~ in this recent state the fibres are held so firmly together by the 1826.] Philosophical Transactions for 1826, Parts I. and II. 135 mucus which surrounds them, and forms them into faseciculi, that it was only under water he could separate an integrant fibre for examination in the field of the microscope. } ‘In its mechanism, he found it to correspond with the ner- vous fibre of a ganglion, differing only in the size of the globules, which were larger than those of the fibre in the ganglion in the proportion of 3,5 parts of an inch to 5,!;5 and Toop pats. 9 ‘ The elastic transparent jelly uniting the globules together, had not the same elasticity as in the nervous fibre, so that it could not be drawn out from the contracted state to double its length without breaking, _ “The muscular fibre of a trout was treated in the same way, and the result was the same; the fibres were however more brittle than those in the bullock’s neck, : “ From these facts, in addition to those communicated in the examination of the structure of ganglions, it is at last ascer- tained, that the structure of the fibres of nerves in general, and those peculiar to ganglions, as well as those that compose muscles, is so far the same, that they consist of single rows of globules united together by an elastic gelatinous transparent matter ; they differ however in the size of the globules, and the degree of elasticity of the medium by which they are united ; so that a less power will elongate a nerve than the fibres of a muscle, and to a greater extent, and it will restore itself with nore yelocity to a state of rest. _ This structure of nerves and muscles, I consider to be de- monstrated in the annexed drawing ; since I cannot believe Mr. Bauer has been led into any error upon this occasion; as no error has been detected in his microscopical observations for so many years continued, and the accuracy of his representations, of what he has seen, no one can doubt. “ It is a curious confirmation of the acuteness of his eye, and the accuracy of his glasses, that Leuwenhoek, who used a single microscope, and says it is the best that can be made, since the magnifying glass isthe smallest speck that can be seen, declares a muscular fibre to be made of globules less than the red glo- bules of the blood; and Dr. Monro of Edinburgh, who pub- lished his microscopical observations on nerves and muscles, in the year 1783, made chiefly in the solar microscope, goes so far as to consider muscular fibres to be the continuation of nervous - fibres, and gives an engraving of the mode in which the one ter- minates, or is lost in the other. Dr. Monro, it is evident, had never seen a single fibre either of a nerve or muscle, only fasci- culi of them, and found them so much alike as to be led to con- sider them the same. Both Leuwenhoek and Monro, from the want of a micrometer, were left to guess at relative dimension, and in such guesses were often very unsuccessful. 136° «Analyses of Books. Fue. *« The globules in the nervous fibre erty Days than in the muscular, oversets Monro’s theory of their being the same ; but that both authors, with means so very inadequate to those em- ployed by Mr. Bauer, should have made such approaches to the truth, is highly creditable to them, and must prove highly satis- factory to Mr: Bauer, as well as to the public.” | VI. An Account of the Heat of July, 1825; together with some Remarks upon sensible Cold ; by W. Heberden, MD. FRS. Some particulars of this communication will be found in the Annals for February last, p. 138 ; and we subjoin the remarks on the estimation of sensible cold with which the paper concludes. “ I am tempted to add to the above some other observations, which, if they are not immediately connected, are not entirely unconnected with this subject ; for it cannot have escaped the attention of any person moderately conversant’ with natural phi- losophy, that the index of a thermometer is a very imperfect _ measure of what I may call the sensible cold, that is, of the » degree of cold perceptible to the human body in its ordinary exposure to the atmosphere. For while the thermometer truly marks the temperature of the medium in which it is placed, the sensations of the body depend altogether upon the rapidity with which its own heat is carried off. And this is by no means confined to the actual temperature’ of the air; but whatever alteration of quality increases its power of conducting heat ; and, above all, whatever currents increase the succession of its particles in contact with the body, the same will increase the sensation of cold. Hence it is, that in very hot weather, the same stream of air which would heat a chamber, will never- theless be cool to the feeling ; on the other hand, when the thermometer was more than 8U° below the freezing point, Cap- tain Parry observed, that while the air was still, the cold was - borne without inconvenience. “ It therefore occurred to me, that the proper way to estimate the sensible cold, would be, first to raise a thermometer to a sin a something exceeding the natural heat of the human body, and then to observe at what rate the quicksilver con- tracted upon exposure to the air. For this purpose I used a thermometer with a very small bulb, which might show the alteration of heat in a short time. This I held to the fire till it rose to about 120°, and then carried it in a -warm.glove into the | open air. I had with me an assistant with a watch in his hand: and as soon as the mercury had descended to 100°, he began to count the seconds, while | continued to observe the thermome- ter, marking the degree of heat at the end of every ten seconds during half a minute. The result rather exceeded my own ex- pectations ; and (being, as far -as I know, the enly experiments of the kind,) I haye thought the Society might not dislike to be made acquainted with them. oes) ; / 1826.] Philosophical Transactions for 1826, Parts I. and IT. 137 ~ « The circumstances that particularly engaged my attention were wind, and moisture. With these views the following ex- periments were made, and verified by repeated trials. ; “ Kap. 1.—1821, January 3. A strong east wind. The tem- perature of the air 31°, ? “‘ The thermometer in this, and all the experiments, being pre- viously raised to 100°, im the manner before-mentioned, the descent of the mercury from that point was observed as follows: ; 3 : ; After 10” it was 78° Decrement 22° 20” 60° 18° 30” — 52° - 8° “ By the decrements, it is to be understood the descent in each successive ten seconds. This is added, because I consider it as the proper measure of the sensible cold, so long as the ther- mometer retains a heat approaching to that of the human body. “ Exp. 2.—1821, January 4. No perceptible wind. ‘The . temperature of the air 30°, the atmosphere hazy. After 10” therm. 89° Decrement 11° ~ 207 ——— 80° i 30” -— 71° fh « Exp. 3,—1821, February 10. A strong east wind. Tem- perature of air 47°. . The atmosphere clear, with sunshine. After 10” therm. 82° Decrement 18° ~ 20” ——-— 73° . ge 30” a 9% aga Bei ge * Exp. 4.—1824, Jan.9. A cold fog. _No wind, Tempera- ture of the air 37°, 7 oun After 10” therm.92° Decrement 8° 20” ——~ 85° ye) YS aicgthuelbl FAT, Go “The most superficial view of these experiments shows the eb 5m effect of wind to increase the rate of cooling, which, apprehend, constitutes sensible cold; so that in experiment 3, though the thermometer suspended in the open air was 17° higher than in experiment 2, yet the sensible cold was very con- siderably greater; but when there was no wind, even a wet fog did not much, if at all, increase it. This, which at first sight may appear contradictory to'experience, is not, I believe, really so; for though the power of such air to carry off the heat of -the body be indeed increased, yet so long as we remain at rest, We are in great measure unaffected by it; so much the effect of wind exceeds that of mere moisture. It is by walking, or riding, in such a state of the atmosphere, that we produce on 138 ne Analyses. of Books. | \ [Ave, our bodies a current of moist air, which is then felt in propor- tion to the rapidity with which we pass through it, If it were thought worth while to bring this to the test of the thermome- ter, the instrument should be made to pass through the air at the same rate as the person would move.” VIL. On the Transit Instrument of the Cambridge Observatory, being a Supplement to a former Paper; by Robert, Woodhouse, | Esq. Plumian Professor of Astronomy in the University of Cambridge. | VIII. Account of a Series of Observations made inthe Summer Fries Year 1825, for the Purpose of determining the Difference of eridians of the Royal Observatories of Greenwich and Paris ; drawn up by J. F. W. Herschel, Esq. MA. Sec. RS.: commu- nicated b the Board of Longitude. . The following is Mr. Herschel’s account of the manner in which these observations were made: | ** Operations having been carried on to a considerable extent in France, and other countries on the Continent, for the purpose of ascertaining differences of longitude by means of signals, simultaneously observed at different points along a chain of stations ; and the Royal Observatory at Paris, in particular, having been connected in this manner with a number of the most important stations, it was considered desirable by the French government that the Royal Observatory at Greenwich should be included in the general design. The British Board of Longitude was accordingly inyited to, lend its co-operation towards carrying into effect a plan for that. purpose; and the ~ invitation being readily accepted on their part, I was deputed, in conjunction with Captain Sabine, in the course of the last sum- mer, to direct the practical details of the operation on the British side of the channel, and to make the necessary observations. Every facility was afforded us in making our dispositions, on the part of the ‘different branches of His Majesty’s government to which it was found necessary to apply. ‘A detachment of artil- lery was placed, by his Grace the Duke of Wellington, Master ‘General of the Ordnance, under the orders of Captain Sabine. Horses, waggons, and men, were furnished for the conveyance of a tent, telescopes, rockets, and other apparatus; and four of the chronometers belonging to the Board of Admiralty were placed at our disposal. The rockets required for making the signals were furnished us from France. It would have. been easy, doubtless, to have procured them from the Royal Arsenal at Woolwich; but on the representation of Colonel Bonne, to whom the principal direction of the operations in France was intrusted, it was thought more advisable to accept an offer made to us of any number which might be required, prepared at Paris expressly for similar operations, carrying a charge of eight ounces of powder, the instantaneous explosion of which, at 1826.] Philosophical Transactions for 1826, Parts I.and IT.189 — their greatest altitude, was to constitute the signals to be observed. - Our previous arrangements. being made, on the 7th of July I left London ; and after visiting the station pitched upon at Wrotham, which was the same with that selected by Captain Kater and Major Colby, as a principal point in their triangulation in 1822; and finding it possessed of every requisite qualifica- tion for the purpose of making the signals, from its commanding situation, being unquestionably the highest ground between Greenwich and the coast, proceeded to Fairlight Down, near Hastings, where I caused the very convenient observatory tent, belonging to the Board of Longitude, to be pitched immediately over the centre of the station of 1821, which was readily found from the effectual methods adopted by the gentlemen who con- ducted the trigonometrical operations in that year, for securing this valuable point. Here, on the 8th, I was joined by Captain Sabine, who, it had been arranged, should proceed to the first observing station on the French side of the Channel, there to obserye, in conjunction with Colonel Bonne, the signals made on the French coast, and those made at the station of Mont Javoult ; which latter were to be observed immediately from the obseryatory at Paris; while, on the other hand, it was agreed that M.le Lieutenant Largeteau, of the French corps of geo- graphical engineers, should attend at Fairlight, on the part of the French commission, and observe, conjointly with myself, the signals made at La Canche, the post on the opposite coast (elevated about 600 feet above the sea, being nearly the level of Fairlight Down) and,also those to be fired from Wrotham Hill, which were expected to be immediately visible from a scaffold, raised for the purpose on the roof of the Royal Observatory of Greenwich. By this arrangement, and by immediate subse- quent communication of the observations made at each station, it was considered that the advantage of two independent lines of connexion, a British anda French, would be secured between the two extreme stations; i. e. the two national observatories ; every possibility of future misunderstanding obviated, and all inconvenience. on either side, arising from delay, or miscarriage in the transmission of observations, be avoided. : ie ** With the assistance of Captain Sabine, and by the help of exact information as to the azimuths of Wrotham and other nearer stations in the triangulation of 1821, with which Captain Kater had obligingly furnished us, and of which Fairlight Church proved the most convenient, being close at hand and * favorably situated, and easily visible in the twilight ; and from the previously calculated azimuth of La Canche (114° 30’ E.) ; four night glasses by Dollond, provided at the order of the Board of Longitude expressly for this operation, and which If had caused to be fixed on posts firmly driven into the ground 140-0 Arialijses'of Books? ee \1 FAYE. beneath the tent, were then pointed, two on the station of La Canche, and two on that of Wrotham Hill. Those directed to the former were of four inches clear aperture, the others. of three. In case of any difficulty arising as to the pointing, I had taken care to provide myself with an excellent eight-inch repeating theodolite, on the Reichenbach construction, by Schenck, of Berne; but it was found unnecessary to use it, as the night glasses were purposely constructed with an azimuthal motion, and a rough graduation read off by an adjustable ver- nier, so as to allow their being set atonce a few minutes before the observations commenced, by taking Fairlight steeple as a zero point; a circumstance which proved exceedingly conve- nient, as it allowed of their being dismounted after onc sight’. observations, and removed to a place of security; and thus rendering it unnecessary to harass our small party by keeping guard in our absence. pa on wk “ On the night of the 8th I had directed blue lights to be fired at Wrotham, as atrial of the visibility of the stations, or rather as a verification of the pointing of the telescopes ; for on the former point there could be no doubt, the station at Wrotham being situated precisely on the edge of the escarpment of the ehalk which borders the Weald of Kent, and having been actually connected with Fairlight by direct observation, while no ob- stacle but a low copse wood, over which it might fairly be presumed that no rocket would fail to rise, separated it from a direct view of Greenwich, at about 20 miles distance. Either from haze in the-atmosphere, or from the too great distance, nothing was seen that night or the next; which however caused no uneasiness, as we could depend on our instruments and information. ' The next morning Capt. Sabine quitted Hastings, and joined Col. Bonne, at his post, on the morning of the 10th, the day appointed for the commencement of the observations ; meanwhile I was joined by M. Largeteau, who remained with me the whole time of their continuance, performing every part of- a most scrupulous and exact observer, as the observations herewith communicated will abundantly testify. “ The observations were continued during 12 nights, 10 signals being made at each rocket station every night. The weather throughout the whole of this time was magnificent, and such as is not very likely to occur again for some years ; a circumstance of the last importance in operations of this nature, where lights. are to be seen across nearly 50 miles of sea, and also by reason of the verification of the sidereal times at the observatories by transits. One night only a local fog deprived us of the sight of 13 out of the 20 signals ; but on the whole, out of 120 made. at Wrotham, no less than 112 were seen from Fairlight (about 40 miles)and 89 from Greenwich; while outof the same number made at La Canche, 93 were observed at the former post. I am sorry to 1826.] Proceedings of Philosophical Societies. 141 add, however, that owing to a combination of untoward. cir- cumstances, which no foresight or exertion on the part of Capt. Sabine or myself could possibly have led us to calculate on, or enabled us to prevent, and which the most zealous endeavours on that of Col. Bonne failed to remedy, no less than 8 out of the 12 nights’ observations were totally lost, as to any result they might have afforded, and the remainder materially SuPPies ; So that a much more moderate estimate of the value of our final result must be formed, than would otherwise have been justified. Still it is satisfactory to be able to. add (such is the excellence of the method), that a result on which considerable reliance can be placed, may be derived from the assemblage of the observa- tions of these four nights; and when it is stated that this result appears not very likely to be the tenth of a second in error, and extremely unlikely to prove erroneous to twice that amount, it will perhaps be allowed that, under such circumstances, more | could fed’ be expected.” | . : The difference of the meridians by these observations is gm 2156. - : po ma -. IX, Observations on the Poison of the Common Toad ; by John Davy, MD. FRS. . gh me aS For an abstract of this paper, see Annals for Feb. p. 137; and for some remarks on the subject of it, see the number for April, ae ey TN “ ‘ i X. On the Magnetizing Power of the more refrangible Solar Rays; by Mrs. M. Somerville: communicated by W. Somer- ville, MD. FRS. : ! _A report of the contents of this paper will be found in the Annals for March, p. 224. : * XI. On the Mutual Action of Sulphuric Acid and Naphtha- line, and on a new Acid produced; by M. Faraday, FRS.&c. _ We shall probably give this paper in a future number ; in the mean time we may refer to that for March, p. 226, for some account of the facts it describes. nyo Tas, YX a, Be (To be continued. ), ArtIcLE XI. Proceedings of Philosophical Societtes. | ASTRONOMICAL SOCIETY - May 12.—A paper, by the Astronomer Royal, was read, con- taining an explanation of the method of observing with the two mural circles, as practised at, present at the Royal Observatory. The principal object of the method explained in this paper is to diminish as much as possible the inaccuracies occasioned, even in the most perfect instrument, by rapid and partial changes of 142 —-—- Proceeilings of Philosophical Societies. [Aue. temperature. In the Greenwich system of observations, assist- atice from the spirit-level or plumb-line, or indeed from any previous verification, is rejected altogether. Two circles are employed simultaneously, each of which is furnished with six microscopes, which it is desirable should be placed at nearl equal distances on the limb ; and previous to observation eac circle is placed nearly in the plane of the’ meridian, and nearly perpendicular to the horizon. Each circle is provided with an artificial horizon of mercury, so as to command the greatest possible portion of the reflected meridian. | The first part of the process consists in observing a number of stars simultaneously with each instrument, either by direct, or by reflected, vision: the object of this is to determine the exact quantity that one instrument marks more or less than the other, when both are directed to the same object. This is determined, not by a single observation, but by a great variety; thus obtaining the quantity denominated the mean difference for every 24 hours. | rireg ii In the second part of the process, a series of stars is observed reciprocally, that is, the direct image of a star by one instru- ment, at the same time that its reflected image is observed by the other. This, combined with the results of the previous pro- cess, in which the mean difference serves the same purpose as the index error in Hadley’s sextant, enables the observer to ascer= tain the altitude; with which is likewise obtained the know- ledge of the position of the horizontal diameter of each instru- ment. The observer, however, does not rest contented with a single determination of one diameter; but must in a similar manner, from altitudes, observed on various points of the are, and by taking sometimes the direct, and sometimes the re- flected, observation with the same instrument, endeavour by every possible variety to obtain the maximum of precision of which the method is capable. The position of the horizontal diameter of each instrument being thus deduced from a mean of all the preceding experi- ments, sufficient data are obtained for computing the places of those stars that have been observed in the first part of the peace, and employed in computing the mean difference ; ecause, without the knowledge of the position of their hori- zontal diameters, the instruments, with respect to the stars in question, give nothing but differences of declination, but such noses being known, their altitudes can be accurately deter- mined. | The Astronomer Royal terminates his paper by pointing out the principal advantages of the method described: ag There were next tead Extracts of three letters addressed by M. Gambart, Director of the Observatory of Marseilles, to James South, Esq. respecting the discovery and elements of 1826.] Linnean Sciety. 149 the orbit of a comet, supposed to be the same with that, or those, of 1772 and 1805. M. Gambart first presents the sum- mary of his observations of this comet from the 9th to the Qist (inclusively) of March this year. He then exhibits the elements as computed from these observations upon the para- bolic hypothesis: viz: - Passage of the perihelion, March 1826, 18,94 days, counting frit thidhlpht: | : Perihelion distance.......... 0-961 \ Long. perihelion .....4...545 104° 20° 0” Long. ascend. node. .....4.. 247 54 10 Sane AARON kwh. a kg (aes 14.39 15 Motion direct. These elements were communicated March 23rd:—a week after, the elliptic elements deduced from the same observations were transmitted, and are as follow: viz. _ i ce: . Passage of thé perihelion, March 1826, 19,5998 days, counting from midnight. Semi-axis major... ss..066. 3567 Eixcentricity . .....«%5. eee. —0°74187 Log. mean motion.......4..: 2°7326487 Long. perthel ...... 2 eh 108° 54 19”: Lotigs ase/ nodes. ooss ee ves 249 55 23 Inélination .:........ bs wee ON TS COOy SF Motion direct. Periodic tue; senses 90:4 1.-.- 6°567 years. The same elements, M. Gambart observes, represent almost . exactly the observations of the comets of 1772 and 1805; whence the identity of all three is inferred. | The reading of Mr. Herschel’s paper on Double-stars, com- menced at the last meeting, was continued. : LINNEAN SOCIETY. feb. 7.—The following papers were read : | A Description of the Plectrophanes Lapponica, a Speciés lately discovered in the British Islands; by P. J. Selby, Esq. FLS. MWS. &c. . = Somé Account of a Collection of Cryptogamic Plants formed in the Ionian Islands, and brovight to this country by Lord Guildford; by R. K. Greville, LLD. FRSE. &c. : Feb. 21.—Vhe reading of Dr. F. Hamilton’s Commentary on the Fourth Part of the Portas Malabaricus, was commenced, March 7.—The reading of Dr. Hamilton’s Commentary was continued. = . Pree 3 Pins March 21.—A paper was read, entitled, Descriptions of Two new Birds, belonging to the family Phasianide; by Major 144 Proceedings of Philosophical Societies. [Ave. General Hardwicke, FLS.; also, a Description of a New Genus, belonging to the Natural Family of Plants, called Scrophu- larine ; by Mr. David Don, Librarian, LS.; and, a Review of the Genus Combretum ; by Mr. George Don, ALS. April 4.—The following papers were read : , On Dichotomous and Gatoace Arrangements.in Natural His tory, by Henry Thomas Colebrooke, Esq. FRS. FLS. &c. The learned author states that what has been called the dicho- tomous arrangement of nature can only be represented on a su- perficies: whereas, the affinities of natural objects ramify in every direction, and cannot .therefore be correctly represented on a plane surface. He then shows that that distribution which, taking one central or interior group, makes only a few equi- distant exterior ones, is necessarily quinary. The centre of the exterior groups will represent the solid angles of a tetrahedron within a sphere of which the centre is the middle point in the interior group. He finally observes, that although the tendency to a.quinary arrangement in natural history has hitherto been chiefly developed in zoology, yet the same principle may be recognised in fotaay, we ae Boswellia, and certain Indian Terebinthacee ; by the same author, ; April 18.—The reading of Mr. Colebrooke’s paper On Bos- wella, &c. was concluded; and a.paper was read, éntitled, Observations on a Species of Szmza, Linn. now alive in the col- lection at Exeter Change, allied to, if. not identical with, the Stmia Lagothrica of Baron Humboldt; by Edward Griffiths, Esq. FLS. met ee ea vio") Lay 2.—A paper was read, On the Locusts, (Gryllus migra- torius, Linn.) which devastated the Crimea, and the southern provinces of Russia, in 1824; by J. Smirnove, Esq. FLS. Secre-' tary tothe Russian Embassy. ag Also, a paper On Indian Annonacee; by H.'T. Colebrooke, Esq. FRS. LS. &c. | , ‘4 May 24.—On this day, being the birth-day of Linneus, the - Anniversary Meeting of the Society was held, when the follow-. ing Fellows were chosen Officers and Council for the ensuing ear. ‘ Prestdent.—Sir James Edward Smith, MD. FRS. &c. Vice Presidents.—Samuel, Lord Bishop of Carlisle, LLD. VPRS. FAS.; A. B. Lambert, Esq. FRS. AS. and HS.; W. G. et age MD. FRS. and AS.; and Edward Lord Stanley, MP. Treasurer.—Edward Forster, Esq. FRS. and HS.- Secretary —James E. Bicheno, Esq. FGS. ? Assistant Secretary—Richard Taylor, Esq. FSA. Mem. Asiat. Soc. Council,—Charles Bell, Esq. FRSE.; John Bostock, MD, - 1826.) 1 Geological Society... 145 FRS. and HS. PGS.; Robert Brown, Esq. FRS:; Charles Konig, Esq. FRS.; Rev. Thomas Rackett, MA. FRS. and AS. ; Sir Thomas Stamford Raffles, Knt. LLD. FRS. AS. and HS.; Joseph Sabines Esq. FRS. and AS.; Nicholas Aylward Vigors, Esq. MA. FRS. ; June 6.—A paper was read on a new Genus of Insects, named Oiketicus; by the Rev. Lansdown Guilding, BA. FLS. : _ Also a paper on Methods and Systems in Natural History ; by J. E. Bicheno, Esq. Sec. LS. June 20.—The following papers were read : > Concise Notice of a Species of Ursus from Nipal, a skin of which has been presented to the Linnean Society by H.T. Cole- | brooke, Esq. FR. and LS. &c.; by Thomas Horsfield, MD. _ FLS. The new species of bear partially described in this notice, appears to be nearer in affinity to the brown European species than to the tropical bears, from which the sub-genera Prochilus - and Helarctos ite been formed. Description of a new British Freshwater Helix; by the Rev. Revett Sheppard, MA. FLS. — : Of the term Oistros, or Gistron, of the ancients, and of the real Insect intended by them in this Expression; by Bracy Clarke, FLS. &c. | It is affirmed in this communication, contrary to the opinion maintained by Mr. W.S. Macleay, and noticed in the Annals for May, 1824, that the (strus of -Linnzeus; and not his Tabanus, is. the true Gistron of the Greeks and Asilus of the Romans. «| gi The Society then adjourned until the 7th of November next. _ GEOLOGICAL SOCIETY. : _ June 16,—A paper was read, entitled, ‘‘ Notes on the Geolo- gical Structure of Cader Idris,” by Arthur Aikin, Esq. FGS. The author, after describing the outline of this mountain- ridge, details the relative altitude and position of the different heights, the situation of the summit overlooking the crater (in. the bottom of which lies ‘the Goat's Pool”) and the various _ faces and slopes of the mountain. : Mynydd pen y, Coed, the highest hill which stands out on the southern slope, is found to consist of beds of bluish grey slate, very regular, rising NE by N, at an angle of about 35°, but bending up sharply at the NE end so as to increase the angle to about 50°. The successive subjacent beds, which occupy the ground to the edge of the crater, are found to ‘consist of greywakké, compact splintery quartz with crystals of pyrites, and, in parts, ochry and cellular, and quartz-rock, differing from. the preceding only by being more vitreous; which last rest. on a blueish grey quartz, rendered porphyritic by a few New Series, you. X1t. L ; 146 Proceedings of Philosophical Societies. | [Aue, | érystals of felspar. These beds all rise NE by N, but their angle of elevation is continually increasing, ‘and the last forms the summit of Craig y Cae. - | From hence to the margin of the crater the space is oceu- pied by alternations in nearly vertical beds of soft glossy slate, of coarse slate with ochry spots and small cells, of greywakké, of porphyritic quartz, and slaty potstone. About the middle of the series is a single bed of brownish grey rock, appearin . be ferruginous quartz intimately mixed with carbonate 0 ime. : The next bed, forming part of the summit of Cader Idfis, composed of globular concretions, very hard, containing specks of pyrites, and melting in very thin shivers into a black glass, is Supposed to be a trap-rock. After minutely detailing the other beds of Cader Idris, their position and angles, the author proceeds to a mountain (forming the northern boundary of the little valley wherein the Goat’s Pool and another small lake are situated), extending for about two miles parallel with Cader Idris. This he calls “ the Stony mountain.” It is composed of rounded tubercular crags and hemispherical bosses of trap, like enormous ovens, rising group above group. Their surfaces are comparatively smooth, and generally reticulated with veins of quartz, which sometimes occurs in areas four or five yards across, several inches thick, of an obscurely slaty structure, and adhering to the surface of the ttap. Many of the eye when seen in profile oi gd to be of a very irregular and thick slaty structure, but, when visited in front and Jooking down upon them, are evidently clusters of columns laterally aggregated, and intersected by oblique irre- gular joints. | | 7 The large quarry of sienite on the Tawyn road is noticed as showing de connection of the trap and of the stratified rocks, and this is also shown in a very interesting manner on the de- scént northwards from Grey Graig, the eastern extremity of Cader Idris. From these and other facts detailed in his paper the author considers it evident that Cader Idris, and the ground between. that mountain and the Mawddoch, as well as the northern boundary of the valley, consist of various well known tran-' sition rocks, rising in general N. by E. or W.—that the beds both at the northern and southern extremities are at low angles, not greater than 20°,—that the intermediate beds are at high angles, egg! to vertical,—that they rest upon and are interrupted by trap-rocks more or less columnar,—that the trap-rocks are surrounded in many places by mantle-form strata, which in some instances are obviously of the same mate- rials as the trap, and differ only in structure, but which some- 1826.] Medico-Botanical Society. - 7 147 | times bear a less obvious resemblance to the trap, and from ex- hibiting a transition from that. to. the rocks that compose the regular strata, are probably the latter, more or less changed by contiguity with the trap. | WERNERIAN NATURAL HISTORY SOCIETY. At a meeting of the Wernerian Natural History Society towards the close of last year, a letter. from Mr. Meynell, of Yarm, Yorkshire, was read, on Changing the Habits of Fishes, and mentioning that he had, for four years past, kept the smelt or spirling (Salmo Eperlanus, Lin.) in a fresh water pond, having no communication with the sea, by means of the Tees or other- wise, and that the smelt had continued to thrive and breed as freely as when they enjoy intercourse with the sea. _ At the sitting of the same society on the 14th January, 1826, Dr. Fleming, of Flisk, exhibited a specimen of the migratory pigeon of North America, shot in Fife on 31st December last, and showed, from the perfect state of the plumage, that the ‘animal had not been in a state of confinement, but had pros bably been wafted across the Atlantic by strong and continued westerly gales.—(Edin. Phil, Journ.) MEDICO-BOTANICAL SOCIETY. | April 14.—Sir James M‘Gregor delivered an address to the members of the Society on being elected President. A communication was read on the different species of Helle- bore used in medicine, and on its use in maniacal cases. May 12.—A paper ‘entitled, “‘ Remarks on the Bitter Prin- ciple existing in the Fruit of Laurus Persea, and onits Use as a tonic Medicine by the Natives of Demerara;” by J. Frost, Esq. FSA. FLS. Director, was read. . une 9.—A collection of specimens of the plants enumerated Aba i neat ag list was presented by W. Anderson, Esq. Mr. Frost delivered a lecture on the properties of Aconitum ag pie pat Conium Maculatum, and their narcotic principles. July 14.—This being the last meeting of the Society during the present session was numerously attended, and, after the. ordinary business had been gone through, a paper, entitled “ A Catalogue of Plants indigenous to Switzerland,” by J. P. Yosy, Esq. was read. Notice was given from the chair that communications for the gold and silver medals must be sent in before the Ist of December. The Society then adjourned to the 13th of October. L | 148 Scientific Notices—Chemistry. [Ave, ArricLte XII. | SCIENTIFIC NOTICES. , CHEMISTRY. © { 1. Crystallization of Sulphur. The peculiar arrangement of the crystals of ice in a case of hoar frost, where every crystal appeared as if it had endea- voured to recede as far as it could from the neighbouring crystals, has been observed and described by Dr. M’Culloch, at page 40, vol. 20. of this Journal. A similar effect may be pointed out as exhibited in crystallized sulphur, The man who melts and purifies the sulphur at the gunpowder works at Wal- tham Abbey is very expert in introducing wires or wooden ‘ forms into the melted sulphur, which, acting as nuclei, cause a crystallization of sulphur as the whole cools, and then, by letting out the liquid portions, the substances introduced are found covered with acicular or prismatic crystals, at times an inch or more in length. In this way he forms letters, names, and the figures of animals, &c. In all these cases the arrange- ment noticed by Dr. M‘Culloch may be observed ; and wherever an angle occurs the convergence of the crystals is very striking and beautiful.—(Journal of Science.) i 1 is | 2. Meconiate of Morphia. | | Dr. Menici has obtained this substance as a simple educt from opium; the following is the process ; Pour distilled water on powder of good opium, placed on a paper filter, gently stirring them. Wash the opium in this ‘manner until it come through colourless; then pass alcohol somewhat diluted through it; and, when it runs colourless, d the insoluble portion in the dark. In this state digest it ivith heat in alcohol of 36° (B) for a few minutes ; the solution when cold will deposit crystals of a light straw colour. From 12 drachms of opium 20 grains of this crystallized meconiate of noes will be obtained. Giornale di Fitsica.—(Dublin Phil. ourn.) , : 3. On the Use of Common Salt and Sulphate of Soda in Glass-making. | | , Muriate of soda and sulphate of soda may be employed, and at times with advantage, in glass-making. A casting is readily obtained of very fine glass, having, when about three’ or four lines in thickness, a very slight green tinge. Its composition is as follows : decrepitated muriate of soda, 100 parts; slaked lime, 100; sand, 140; clippings of glass of the same quality, from 50 parts to 200. Sulphate of soda likewise offers a great 1826.] Scientific Notices—Miscellaneous. 149 | economy in its employment. The results are very satisfactory. The glasses made of this salt were of a very fine quality. The - following is the composition: dry sulphate of soda, 100 parts ; slaked lime, 12; powdered charcoal, 19; sand, 225; broken glass, from 50 to 200. These proportions give a rich coloured glass, which may be employed with advantage in glass. houses, where a fine quality is sought after. The following is the second way of operating with sulphate of soda; the proportions may be as follow: dry sulphate of soda, 100 parts; slaked lime, 266; sand, 500; broken glass, from 50 to 200. According to _ this’process, it is obviously easy to operate in a regular manner, and to avoid expensive trials in the manufacture. Leguay, Annales de v Industrie Nationale.—(Edin. Phil. Jour.) | 4. Inspiration of Hydrogen. , Signor Cardone, after having emptied his lungs as much as possible of common air, inspired 30 cubical inches of hydrogen at two inspirations. An oppressive difficulty of breathing, and a painful constriction at the superior orifice of the stomach came on, followed by abundant perspiration, tremor of the body, heat, nausea, and violent headache. Vision was indistinct, and a deep murmur confused his hearing. , These symptoms shortly disappeared, except the heat, which increased so as to excite considerable apprehension, but soon gave way to the use of cold drinks. He was speedily reco- vered. Giornale di fisica—(Dubtin Phil. Jour.) MiscELLANEOUS. | ! 5. Intelligence from the Land Arctic Expedition, under Captain Franklin and Dr. Richardson. . The following contains an interesting statement of the pro- gress of the Land Arctic Expedition under Captain Franklin and Dr. Richardson, up to September last, which is the latest information from the travellers :— | “« We have travelled incessantly since we left lake Superior. We overtook our boats, which, with their crews, left England in June, 1824, eight months before us, about half way to this place, or four or five days march to the southward of Mathye Portage. We embarked in them at Chepewyn on the 20th July, and arrived in Mackenzie’s River on the 31st. At Fort Normans Dr. Richardson separated from the rest of the party. Captain Franklin and Mr. Kendal went down the river to the sea in one boat, whilst Dr. Richardson brought the others and their cargoes up Bear Lake River, which falls into the Mackenzie a few miles below Fort Normans. Franklin made a prosperous voyage, and on the 16th of August, exactly six months from the day he sailed from Liverpool, had an extensive view from the summit of Garry’s Island of the open sea, clear of ice, with many black whales, belugas, and seals, ‘playing about. The water at 150 Scientific Notices— Miscellaneous, [Aus. Whale Island is, as Mackensie states in this chart, fresh; but, afew miles from Garry’s Island, which is thirty miles to sea- ward, and out of sight of the other, it changes its colour and: taste. The mighty volume of water which rolls .down. the. Mackenzie, carries shoals of sand, and a brackish stream a long. way out. Captain Franklin did not join Dr. Richardson ‘ his party before the 5th September last, at Fort Franklin, in Bear Lake, the navigation up the river being tedious, from the, strength of the current. The Sharpeyes or Dessrallent of Mac- kenzie, who inhabit the lower parts of the river, resemble. the Esquimaux a good deal in their manners and language, and. that part of the tribe who live nearest the sea were partially understood by our Esquimaux interpreter. The Esquimaux. being at this season inland, hunting the rein-deer, were not seen, but the Sharpeyes have promised to give them notice of our intended yoyage next year. Every thing at present pro- mises success to our future operations. The boats sent out from England answer admirably, and we are well provided with stores for the voyage. During Captain Franklin’s absence Dr. Richardson surveyed this lake, which is about 120 miles long, extending from lat. 65° 10’, long. 123° 29’, where Fort Franklin is built, to lat. 67°, long. 119°, within 70 miles of the nearest bend of the Coppermine River, and about 85 miles from- its mouth. Garr ‘Island lies in lat. 69° 29’, long. 135° 42’, about 450 miles Aad the mouth of the Coppermine, and about 600 from Icy Cape, distances which may easily be accom- plished, even during the short period that the Arctic Sea is. navigable for boats, if no greater obstacles occur than were visible from the mouth of Mackenzie’s river, . A canoe is to be deposited at the north eastern arm of this lake, by which the eastern party will save 200 miles of land journey on their return. But a very cursory view of the rocks was taken in the voyage down the river, as was to be expected from the rapidity with which the party travelled.. The oldest rocks met with were in the portions of the rocky mountains which skirt the river, and which are composed of transition limestone, From that there is a very complete series of formations down to the new red sand stone, exposed in various parts. The rocks of the coal . formation are particularly interesting, from the strong resem- blance the organic remains found in the sandstone, slate, and bituminous shale, have to those seen in England. . They met with several lepidodendra, compressed like the: English ones; also impressions of ferns and reeds. They had not, however, found any beds of coal belonging to this formation, but large deposits of a new bituminous wood-coal, mixed with layers of mineral pitch. This is found in various parts of the river, and on Garry’s Island at its mouth, sometimes deposited on the fixed rocks, but never, as far as could be ascertained, under 1826,} — Scientific, Notices—Miscellaneous. 151 any of them. It is. generally associated with a rich earthy loam, and seems to derive its origin from great deposits of timber, compressed under alluvial, or, to speak in a newer lan- guage, diluyial matters, and impregnated with the bitumen, exuding in immense quantities from the carboniferous limestone, which exists in enormous masses in this country, constituting - whole districts and ridges of mountains. The shells and co- rallines of the limestone are very fine and perfect. The fibrous structure, and, indeed,, the shape of the trees, may still be clearly traced in the coal. From the twisted state of the woody layers, I suspect thata great portion of the coal has been formed from roots, or from trees that have grown in a climate equally — severe with this; the resemblance being very perfect to the | wood of the spruce fir, which grows in the surrounding country,” oc ren, : Additional Information. “« Here J am once more housed for the winter. Hebrum prospiciens, et nive candidam Thracem, ac pede barbaro Lustratum Rhodopen. ; After six months of constant travelling our winter residence is pleasantly situate on the bank of a lake 150 miles long, deep, aud abounding in fish, its shores well wooded, considering the high latitude, and frequented by moose deer, musk oxen, and rein deer. We have abundant stores for next year’s voyage, but our party is large, and we depend on the fishery and chase for support during the winter, yet hope to fare well. In our excursion of three weeks along the lake, which I. made since my arrival, I obtained a boat load of excellent venison, and our nets have occasionally given us 50 or 60 trout ina day, weighing each from 20 1b. to 50 1b. besides 200 to 300 of a smaller fish, called fresh water herrings. Notwithstanding all these com- forts the wiser part of us live in some fear; for any sudden amelioration of the climate, produced by the approach of a comet to the earth, or any other of the commotions amongst the heavenly orbs, dreaded by astronomers, might cause us to be swept into the lake, as, our fort being built on an ice berg, a thaw might prove fatal to its stability. The ground, although it: produces. trees of considerable size, is constantly frozen; the » mud with which our house is plastered was dug out by the aid of fires last month, and now, at the close of the summer, the excavation under our hallfloor, which we intended to convert into a cellar, has been worked only to the depth of three feet, its walls of clay being frozen as firm and harder than a rock. I hope, however, we shall escape such a catastrophe, as Moore, - in his almanack, says nothing about it; unless, indeed, he Means to give usa hint, when he says, ‘ About this time, before ' ae Scientific Notices—Miscellaneous. [Ave. or after, certain northern powers will make some stir in the waters.’ Ayia “ T have had no fly fishing for want of proper tackle. The gigantic trout of this lake would disdain such a mosquito as we were wont to fish with, and I see no pleasure in bobbing for them with a cod-hook and cable. One of the monsters might take a fancy to drag the fisherman to his sublacustrine abodes. ‘Captain Franklin and Mr. Kendal have been to the sea, which they found in lat. 69° 29', quite clear of ice, on the 16th of August. Mackenzie was very near it in his voyage down © the river which bears his name, but did not reach the salt. water by about thirty miles. They left letters for Captain, Parry and his officers from their friends in England, buried at the foot of a pole, on which they suspended a flag. They returned only yes- terday, and the despatch by which [I send this, sets out to- morrow, with intelligence of their proceedings to government. “« Mr., or at all events, Mrs. H., will rejoice to hear that we have a Highland piper, and a crew, hardy and hearty, sons of the mist, who foot it every night, after the labours of the day, to the sound of their native music. We lack only a little of the mountain dew to invigorate the dance. For my part I think water a more wholesome beverage; but there is a great deal in the name, and prejudices are difficult to be overcome.” iy To the preceding very gratifying intelligence the Scotch editor adds the following remarks: ‘ Franklin has thus, in our pee succeeded in realizing, to a certain extent, the views of the learned and distinguished secretary Barrow. We ar- dently hope and trust, that the honour of effecting the north- west passage will not be allowed to pass from us, and that Cap- tain Parry will be again dispatched to finish this grand nautical enterprise. The Congress of the United States, we are informed, at this moment are considering a proposal laid. before them for the discovery of the north-west passage, which, from the known activity of that body, may be agreed to, and thus, in ail proba- bility, we shall hear of the American flag traversing the Polar Sea, and doubling Icy Cape. The Americans, by this atchieve- ment,would secure to themselves,and deservedly, asplendid name in the annals of geographical discovery—a name that ought to be ours, and which would add another and enduring laurel to the wreath of glory which surrounds. the maritime Scat of this nation.”—(Edinburgh New Philosophical Journal.) 6. Stereotype Printing... A new and, as it is said, improved method of stereotyping, has been announced in the Gazette de Munich. It is the in- vention of M. Senefelder, to whom the world is indebted for the art of lithography, and is as follows: a sheet of common printing paper is covered with a layer of earthy matter (query, - 1826.) _ Scientific Notices— Miscellaneous. 153 laster or clay); previously mixed with a sufficiency of water, half a line in thickness. In about half an hour it assumes the consistency of paste, and is then put into the frames over the type, composed in the ordinary way, but not inked ; in this way the printing is modelled, or engraved, in the paste above. These sheets are then dried on a’stone plate, and the fused stereotype metal poured over them. The writing will then be obtained in relief on a thin plate of metal, the characters being ng se well formed with the original type. The proofs taken from these stereotype plates do not differ from those taken from the form of moveable characters. ‘The author of the discovery proposes to reveal his process minutely, so soon as he has obtaimed thirty subscribers at 100 florins each. The expence of the apparatus required for making the castings he estimates at 100 florins, or about 11d. 3s. 8d., and that of the paper covered with the earthy paste at six kreutzers, or 2.68 pence per sheet.—(Journal of Science.) ) : 7. On an Air-Pump, without Artificial Valves. By W. Ritchie, AM. Rector of Tain Academy. ' In the common construction of the air-pump the valves are very liable to be deranged, the repairing of which is attended with much trouble and expence. In the following con- struction no such derangement can possibly take place, which must, of itself give this air-pump a decided advantage. The machine consists of a barrel 3 shut at the lower end, and having a small aperture at C, forming a’ free communication with the receiver F; the piston D is solid, and stuffed in the usual way. The piston rod — works in a small stuffing box at A, so as to render it completely air- ; tight. There is a small aperture at a E in the top of the barrel, to allow the air to make its escape when the piston is raised. This air-pump may =) be worked in the usual way, or by the method of continued motion. In commencing the exhaustion of the receiver, the piston is supposed to be below the small aperture at C. AE ely WTOROT The piston is then raised, and the air which occupied the barrel _is forced out through the aperture at E. The point of one of the fingers is applied to the perforation, in the same manner as in playing the German flute. The air easily passes by the finger, which, when the piston begins to’descend, shuts the - Opening, and completely prevents the entrance of the external i) iit ah til ne 154 Scientific Notices— Miscellaneous. [Ave, air, The piston is again forced down below the opening C, the air in the receiver rushes into the barrel, and is again expelled by the ascending piston. ar , Since the air in the receiver has no valve to open by its elasticity, it is obvious that there is no limit to the degree of exhaustion, as inthe commonconstruction. (Ed. New Phil. Jour.) 8. Hardening of Steel Dies. | Mr. Adam Eckfeldt is stated to be the first who employed the following successful mode of hardening steel dies. He caused a vessel, holding 200 gallons of water, to be placed in the upper part of the building, at the height of forty feet above the room in which the dies were to be hardened; from this vessel the water was conducted down through a pipe of one inch and a p Ste in diameter, with a cock at the bottom, and nozzles of ifferent sizes, to regulate the diameter of the jet of water, Under one of these was placed the heated dies, the water being directed on to the centre of the upper surface. The first expe- riment was tried in the year 1795, and the same mode has been ever since pursued (at the Mint) without a single instance of failure. . | By this process the die is hardened in such a way as best to sustain the pressure to which it is to be subjected; and the middle of the face, which, by the former process, was apt to remain soft, now becomes the hardest part. The hardened part of the dies so managed, were it to be separated, would be found to be in the segment of a sphere, resting in the lower softer part as ina dish, the hardness, of course, hr decreasing as you descend toward the foot. Dies thus hardened preserve their forms till fairly worn out.—(Franklin’s Journal.) | 9. Cutaneous Absorption. The following experiments on this subject have been made by M. Collard:—1. Having immersed his hands as far as the wrists in hot water for two hours and a half, he found that the veins of the hand and fore arm were swelled, and also the lymphatic ganglions in the axilla. 2. Having kept his hands for an hour in.a vessel filled with water, of which he had ascertained the capacity and surface, he found, on withdrawing them, ‘that the vessel had lost more water than another placed as exactly as pantie in the same circumstances. 5. A funnel being closed elow and filled with water, the hand was applied to the upper part; the portion of skin within the funnel was gradually drawn inwards, as if by the formation of a small vacuum. 4. The ex- periment was repeated with a funnel, the neck of which was graduated, and in which was a bubble of air, to indicate by its position any absorption; the results coincided with the last. - 5, A glass syphon had its shortest leg enlarged into a funnel, | 1826,] _ Scientific Notices--Miscellaneous. 155 mercury was placed in the bend, and the funnel extremity being filled. with water, was covered by the hand for two hours ; the mercury gradually approached the hand, proving, with the other experiments, as M. Collard thinks, the absorption of water by the skin, Archives Gen. Fev——(Journal of Science.) | 10. Animal Magnetism in France. _ A commission of the Academy Royale de Medicine has ac- tually reported relative to animal magnetism, |. That the judge- ment given in 1784, by the members of the Academy of Sciences and of the Royal Society of Medicine, charged with the exami- nation ; since, in matters.of science, a first judgement has been too often found defective, and because the researches made by them had not been made with all the care that the habit of ex- perimenting has since introduced. 2. That the magnetism on which judgement was pronounced in 1784 differs entirely in theory, practice, and phenomena, from that now to be consi- dered. 3. That magnetism, having not fallen into the hands of learned men and physicians, and being a special subject of study _ In most of the colleges of medicine in other countries of Europe, itis for the honour of French physicians not to be behind those of other nations. In fact, that considering magnetism as a secret remedy, it is not only an amusement but a duty of the Academy to take notice of it.—(Journal of Science.) 11. Fossil Megalosaurus and Didelphis, “« The bones of the Megalosaurus occur at Stonesfield, in strata of an oolitic limestone slate, which is wrought for roofing houses ; and in the same quarries, which abound in organic remains, there have been found several portions of a jaw, which un- doubtedly belong to a small insectivorous animal, of the order carnivora, which has been by some referred to the genus Di- delphis.. There occur in the same strata bones of birds and reptiles, teeth of fishes, elytra of insects, and vestiges of marine and terrestrial plants. . Notwithstanding this association of fossils, hitherto regarded as foreign to the deposits beneath the chalk formation,-English geologists have been led to think that the Stonesfield slate forms part of the middle oolite system ; and it is very remarkable, that at Cuckfield, in Sussex (the only place in which there has hitherto been discovered a great number of fossils, similar to those of Stonesfield), the strata which contain them form parts of the formation of the iron sand, inferior to the chalk, which is much newer than the middle oolite deposits.. The following, according to Mr. Buckland, is a list, of the fossils, which are found equally in the limestone slate of Stonesfield and the iron sand of ‘Tilgate Forest: bones — of birds; of the megalosaurus ; of the plesiosaurus; scales, teeth, and bones of a crocodile ; humerus and ribs of cetacea, > 156 New Scientific Books. | [Aue. scales of tortoises; the same variety of shark’s teeth (Glosso petra); spines of baliste ; palates, teeth, and scales, of various. fishes ; fossil wood; impressions of ferns and reeds ; | some fragments converted ito charcoal, and some rolled pebbles of uartz.” Dr. Buckland considers these two deposits to have been formed under similar circumstances, at different and remote periods; M. C. Prevost regards them “ as having been fornied at a period much newer than that of the oolitic formations; in short, that theyare tertiary and not secondary deposits,”—( Edin. Phil. Journ.) | 12. Heart of the Frog used for Poison. © The Javanese, it is said, employ the heart of the frog named kadok kesse for preparing a poison. The blood of the reptiles is also considered as venomous, and is used for poisoning daggers or knives. _ It is known that the blood of a frog is em- ployed by the Americans for producing variegated feathers in parrots : some of the feathers are plucked out, and the place where they grew imbued with the blood of the reptile, after which there are produced very beautiful feathers of various colours.—( Edin. New Phil. Journ.) : 13. Taming Rattle-Snakes. Mr. Neale, it.is said, has succeeded in America in taming rattle-snakes, by means of music, so as to prevent them. doing any harm. ‘This author asserts, that they really possess: the power of enchanting animals, or of rendering them motionless through terror; for he says he has seen examples even in his garden. The eflluvie of these reptiles has nothing nauseous in it,—( Edin. New Phil. Journ.) Arzicte XIII. ~ NEW SCIENTIFIC BOOKS. PREPARING FOR PUBLICATION, General Directions for Collecting and Preserving Exotic Insects and Crustacea, with illustrative Plates; by George Samouelle, ALS. Author of the Entomologist’s Useful Compendium: ' | Institutions of Physiology; by J. F. Blumenbach, MD. Professor. of Medicine in the University of Gottingen: ‘Translated from the last Latin Edition, with copious Notes, by John Elliotson, MD. A Concise Historical View of Galvanism, with Observations on its Chemical Properties and Medical Efficacy in Chronic Diseases; by M. La Beaume, Electrician, FLS; &c. 1826.] i F New Patents. 157 The Bariquet ; or the Hibtoiy of America; by Father Michael Chamich. Translated from the original American, by Johannes Avdall, and dedicated to the Asiatic Society. ° JUST PUBLISHED. _Lizars’ Anatomical Plates, Part X. containing the Organs of Sense and Viscera. Demy folio, 10s. 6d. ; plain. 1/. 1s. coloured, Shute’s Medical Science, vol. 2. 18s. . Life and Character of Dr. Bateman. ‘7s. 6d. ArticLteE XIV. NEW PATENTS. T. J. Knowlys, Trinity College, Oxford, for a new manufacture of ornamental metal.—June 13. -T. Halahan, York Street, Dublin, Lieutenant i in the Royal Navy, for machinery or apparatus for working ordnance.—June 22. L. Aubrey, Two Waters, Herts, engineer, for an improvement or improvements in the web or wire for making paper.—July 4. J. Poole, Sheffield, shop-keeper, for improvements in the steam engine boilers, or steam generators, applicable also to the evaporation of other fluids.—July 4. D. Freeman, Wakefield, sadler, for improvements in measuring for and making collars for horses and other cattle—J uly 4. P. Groves, Liverpool-street, for improvements in manufacturing or making white lead —July 4. R. Wornam, Wigmore-street, Cavendish-square, pianoforte maker, for improvements on pianofortes.—July 4. P. Groves, Liverpool-street, for improvements in making paint or pigment for preparing and combining a substance or material with oil, turpentine, and other ingredients.—July 10. 5. Lowe, Birmingham, gilt toy manufacturer, for improvements in useful and ornamental dressing pins.—July 14. J. Guy and J. Harrison, Workington, Cumberland, straw-hat manu- facturer, for an improved method of preparing straw and grass to be used in the manufacture of hats and bonnets.—Jul y 14. J. P. de la Fous, George-street, Hanover -square, dentist, and W. Littlewart, Saint Mary Axe, mathematical instrument maker, for . an improvement in securing or mooring ships and other floating bodies, and apparatus for performing the same.—July 14.° E. Bayliffe, Kendall, Westmoreland, worsted-spinner, for improve- _ ments in the machinery used for the operations of drawing, roving, and spinning of sheep and lambs’ wool.—July 14. . J.L. Higgins, Oxford-street, for improvements in the construction a cat blocks. and fish hooks, and in the application thereof. uy 14. ‘ye 158 Mr, Giddy’s Meteorological Journal. [Avc. ’ ARTICLE XV, Extracts from the Meteorological Journal kept at the Apartments of the Royal Geological Society of Cornwall, Penzance. By Mr. E. C. Giddy, Curator, ro : Barometer. _| Recist. Term. R ain in }100_ of Wino. ReMARKs. Mean. \inches. Bas 3826 29°82| 29-80 /29'810| 70 | 58 | 64-0. 29°78} 29°76 [29°770| 70 | 61 | 64:5 | 0+150 29-52| 29-50|29:510| 68 | 60 | 64-0 29-70 | 29-68 29-690) 69 | 59 | 64-0 29-82| 29-80 /29-810| 69 | 58 | 63:5 | | 29°86| 29-44 /29°850| 68 | GO | 64-0 | 0-050 29-92 29-90|29-910| 73 | 56) 64-5 | 29-96| 29-94|29-950! 69 | 56 | 625 29°98 | 29°96 |29-970| 70 | 59 | 64:5 30-00 | 29-90 |29-950| 68 | 59 | 63°5 29-70 | 29-65 |29'675| 63 | 57 | 600] 80} 29-80 29-800! 64 | 55 | 59-5 | 0-120 30°12| 29-50 |29-872| 80 | 52 | 64-5 | 0-690 RESULTS. Barometer, mean height ......0s0+se0eeeeseee+ 29872 Register Thermometer, ditto eee eres eeeeesseeee 64°5° Rain, No. 1, 0-690, No.2, 1°240. Prevailing wind, NW. No. 1. This rain guage is fixed on the top of the Museum of the Royal Geological Society of Cornwall, 45 feet above the ground, and 143 ‘above the level of the sea. No. 2. Close to the ground, 90 feet above the level of the sea.’ Penzance, July 23, 1826. EDWARD C. GIDDY. \ 1896,] /-. Mr. Howard’s Meteorological Journal. 159 ARTICLE XVI. METEOROLOGIGAL TABLE. em Bisse : © Baromerer, © Turrmomerer. |’ OPE. Adah 1826, Wind. | Max. ‘Min. | Max. Min. | Evap. | Rain. 6th Mon. June 1'IN E} 30°05 30°03 © 64 51 _— 60 JIN. E!. 30°23 30°05 62 47 _ OF 3IN W). 30°34 30°23 70 42 — 4'N Wi: 30°43 30°34 70 52 a SIN W| 30-44 | 9043 | 72 | 46 | — 6IN, Wi 30°44 30°36 76 54 ce TAN 30 37 30°36 68 52 — SIN E| 30°36 SOLA athe 50 —_— ON E| 30:17 30°12 76 50 "95° ‘10N E| 3020 | 3012 | 80 | 52.|,— 11\N: wl 3036 | 3020 | 81°} 50 | — 1ZN W) 30°38 30°36 | .88 62> i 13;\S W|. 30°36 30°35 88 53 — 14IN Wi. 30:35..|. 3031 .| 82 | 66-|-— 15iN Wi 30°38 30:27 83 49 —_ 16\IN. W). 30°50 30°38 75 45 *90 17iIN.. W| 30°50 80°40 75 55 —_ 18iIN- Wi 30°49 30°40 83 48 - — 19S ~E|.. 30°56 80°49 76 45 soe 20\N . E|.. 30°56 $055: +75 «|: 48 — QIN E| 30°55 30°50 68 53 oe 29\N B)- 30°51 | 3050 | 75 | 48 | ‘94 23IN E| 30°51 30°51 80 45 — QIN El 30°51 | 3045 | 84 | 45 | — ~ 95 - EB 30°45 30°33 85 47 —_ 26| E 30°33. 30°16 88 57 —_ 27\S EL. 30°17 30°16 92 62 95 52 9281S. E| 30°96 30°16 91» 58 — 29° W 30°30 30°26 82 58 — 30, S | 30°30 | 3028 | 87 | 62 | 48} .05 30°56 30°03 92 43 4°22 | 1°18 The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column, the result is included in the next following observation. A dash denotes that 160 Mr, Howard’s Meteorological Journal. _ [AuG, 1826. - _ REMARKS. Sirth Month.—1, Night rainy: showers during the day. 2. Cloudy. 3—26. Fine. 27. Sultry: a thunder storm from 11 to’J, with heavy rain. 28, Fine: sultry, 29, 30, Fine. , . ; « © . / - RESULTS. Winds: N, 1; NE, 10; E,2; SE,3;'8,15 SW, 1; W,1; NW, 11.” / - Barometer: Mean height For the ahonth. eeee. shaitdie Litecs be odin eieas Lose 30-343 inches. Thermometer: Mean height : For the sbnnth. .:[50.. iwc Cle eRe ak ccs b ew 64°266° Evaporation se 2 a crate Yaunk dali emi te fn SAC le 4°22 in, ‘Rain. bd deb chne doivctbckr inet) ukkak Cink VRtpitn te }- << emaelie Mons 118 “> / - 4 Laboratory, Stratford, Seventh Month, 26, 1826. __ __. RB. HOWARD. ANNALS” PHILOSOPHY. SEPTEMBER, 1826, ARTICLE I. . A Chemical Essay on the Art.of Baking Bread. By Hugh Colquhoun, MD. (To the Editors of the Annals of Philosophy.) GENTLEMEN, by . Few chemical processes concern the health and comfort of every individual in the country more directly and immediately than the art of baking bread, and yet there are, perhaps, not many the rationale of which is less generally familiar. ‘There is little of attraction about the operations of a bake-house, and. it is far from pleasant, to any ordinary observer, to follow the flour, through its various progressive changes, to the. oven, and then to superintend it in the last stage of its formation into bread. | But the remark is a true and a trite one, that the most showy and striking phenomena are not always the most truly interesting or instructive when examined; and inthe most com- mon of all the mechanical arts, it will be occasionally found, that there still remains room for amendments, even obvious to the theorist who, enters unprejudiced.upon the study of the system, though they may have long escaped the notice of the mechanic, bred up to follow a monotonous routine, which he-is either too indolent, or too ignorant, or too timid, or too much — the slave of habit, to think of disturbing. The following Essay is submitted, therefore, to the public, in the hope, that while it may prove not unworthy of the chemist’s attention, 1t may also be the means of conveying some useful practical hints to the mechanic. At the same time, it is necessary to premise, that - in‘regard to some of the manipulatory improvements which are - proposed in the following pages, the only remarkable thing is that they should have remained till now almost entirely, if not indeed altogether, unknown to the baker’s practice. It has not : —— much science to suggest perhaps the principal among New Series, vOL. xl. M 162 Dr. Colquhoun’s Essay [Sepr, them, and yet the advantages which their use promises seem to be far from inconsiderable. In ne this Essay; it has beem necessary not only to consult the views and experiments of former writers, but, in order to elucidate some of the processes connected with the art, to perform various experiments entirely new, and also in many instances to. verify carefully the results stated to. have been obtained by others. Wherever an experiment is quoted upon authority merely, a reference is given, and where this is not done, the author holds himself responsible for the accuracy of his details. Baked bread, simply considered, may be described as being a substance formed by mixing a portion of the seeds of any ‘of the cereal grasses with a little water, and then cooking the - whole, by means of fire, into a solid. consistent state. In the earliest stage of the art, the process probably consisted of but a very fewsteps. And indeed the first cook who discovered that by previously moistening and then baking grain, a compact cake of bod could be formed, fitted to contain within-a small bulk a large supply of nutrition, to keep entire for an indefinite length of time in proper situations, and to yield when masticated a most agreeable relish to the palate, may perhaps be regarded as having made a step in the art of baking bread, of more difficulty in itself, and of greater importance ‘to the species, than any. thing that subsequent improvement has supplied. Forin all the: intricacies and refinements of our modern cookery of bread, there can surely be found nothing to compare with that which first taught man to use a great proportion of kis food ina man- ner peculiar to himself, and. raised him above the practice of devouring it as raw grain in common with the lower animals. What may be conjectured to have been the second leading-step of advancement in the art, that of reducing the grain to powder, before applying to it the moisture which should form the solid cake after the application of heat, seems perhaps of more natural and easy suggestion than.the other; and accordingly we find at this day few nations refined enough to practise baking at all, who are yet so rude as not to make their cakes of bread out of ground grain. isis - But there still remained another distinct department of mani- pulation, to be introduced into the art of baking, before it, contained all. the rudiments of what has now been gradually perfected into the modern system. And this latter improvement: certainly seems to savour more of refinement and civilization in: its introduction and regular use, at the same time that it is of too» old a date to have left even any. tradition of its origin or inven- tion. It consists in mixing with the constitution of the bread a light gaseous. body; and, in actual practice, this is almost inva-' - Ttablycof the-same kind with that which gives the foam to ale: ' 1826.} on the Art of Baking Bread: 163 and porter, and the sparkle to champaigne. This gas, when duly infused into the dough, gives us, after baking and cooling, instead of a heavy and hard, or tough dull nutriment, a light, porous, elastic, diaphanous food, which is at once more agree- able to the palate, and, as of easier digestion, more conducive to the health, Common sea biscuit is no bad specimen of the former of these kinds of bread, while a good modern plain wheat loaf is a fair example of the latter. And if one will just imagine a mass of the dough of sea biscuit baked into the bulk and shape of a common wheat loaf, the comparative qualities of the two varieties of bread will appear evident. The one would prove a hard, compact, heavy body, which it would be difficult to cut down or to chew, while the other would be light, semi- transparent, and full of little vesicles of air so as to resemble*a. sponge in lightness and ‘elasticity. In addition to this, it is not: immaterial to observe that these vesicles in well made bread are regularly arranged in a sort of stratification of layers one above? another, all of them perpendicular to the crust of the bread.’ This kind of internal structure constitutes what 1s termed by the bakers piled bread ; and this appearance: they are: in the habit: of regarding as one of the surest tests of the success of their batch. : | VISICHIBTYS 3 These distinctions are marked and decisive. They place'in a sufficiently striking light the great advantages derived to man- kind from the introduction of that part of the process of baking ~ which consists in mingling with the bread they eat a considerable volume of what must be regarded asa foreign and innutritious body. And it may be proper to mention as a circumstance which throws some light on the increased facility of digestion: possessed by well-piled bread, that if a portion of it, after hav- ing been duly baked and thoroughly cooled, be pressed between the fingers, it will crumble readily into powder; and if a piece of such a loaf be placed im hot water, it immediately softens, swells out considerably, disintegrates, and admits of beimg easily diffused throughout the liquid. But if a bit of unpiled bread be similarly squeezed between the fingers, it remains a solid cohe- sive mass, and when put into hot water, never softens further than to become a permanently-tough mass of dough. The various modes which have been resorted to for the pur- pose of introducing the gaseous principle into bread, form almost the whole matter of interesting research which is connected with the modern art of baking. The rest, as has been already adverted to, resolves itself into a pretty simple and by no means — very curious process of cookery, being merely the commixture, in due proportions, of flour, and salt, and water, with the occa- sional addition of confectionary, after which the compound is baked in the oven. The only curious chemical investigation connected with the art, is, therefore, the examination of the use mM 2 164 Dé: Coljuboun's Essay: (Serr. and’ operation of the gaseous principle thus artificially introduced: into bread for the purpose of rendering it light and elastic, and this shall form the subject of the present Essay, ~ fiona thir In conducting this inquiry, we shall commence, for the sake of|perspicuity, by stating shortly the mechanicakhistory cf the mdst ordinary process of baking. We shall next’ consider in a chemical point.of view the use and object ofeach part of the: process, in so far as it contributes towards the duly gasifying* of bread, so as to render it that light and spongy food which — -makes it at once both pleasant and wholesome. And in dis- cussing this matter, we shall divide the Essdy' into two parts.’ The first of these we shall devote exclusively to the process of. om fermentation, by far the most interesting and extensively’ useful, of all the methods employed by the baker in order to. impregnate his dough with:the elastic fluid, In the second, we: shall consider more cursorily a few of the principal among the’ other chemical processes resorted to by the baker, with a view to,gasify.his bread.. Among: these,’ we ‘shall. find that there is: one, used in the manufacture of gingerbread, sufficiently import-' ant in itself, and sufficiently curious and anomalous with respect’ to, its rationale, to require a much more careful and minute examination than any of the others; and with this we shall’ conclude the Essay. ) PRE Soh ghd br tl dag Mechanical Details of the most common, Process in the Art of hs , Baking Bread,,...., Sia ek ‘The spontaneous decomposition of a piece of wheat dough, always generates within the massa quantity of carbonic acid gas; and. it is the formation of this. gas which is the baker’s object in exciting fermentation, The modes employed by him may therefore be considered comparatively good, in proportion. as they more perfectly and rapidly produce the internal gas. -Perkaps the mostsimple process for efiecting this, is to place a portion of common dough apart, ina warm situation, where, if allowed to remain a sufficient length of time, it will pass sponta-: neously into a state of decomposition, which will generate car- bonic acid gas within it, and give the bread that is baked from. it both lightness and vesicularity. This system, however, is attended not.only with considerable delay, but with the further disadvantage, that such dough is never entirely free from acescence or putrescence, either of which is always injurious to the flavour of the bread, and may even, if existing in excess, prove detrimental to its wholesomeness. But the process of decomposition will be found to be greatly accelerated in any recent mass of fresh dough, by the addition, of a small portion of old dough already in a state of strong fermentation. When this * For shortness’ sake the term gasifying is used to express the common infusion of a gaseous or elastic fluid into the system of dough. 1826.] on the Art of Baking Bread. 165 is. done, the mass is said to be leavened, the dough thus added while under fermentation being denominated /eaven. The prac- tice of leavening bread is: familiar to every one, as having been known at the earliest periods of which we have any authentic records., And, in point of fact, the same system, hg another process is superadded to it, forms a leading part of the art of baking in the most civilized countries at the present day ; for it is the almost invariable practice of the baker to induce fermentation, not in the whole dough. at once, but in a portion only, with which the rest is afterwards leavened ; and thus it'is found, that the tendency to decomposition may be more rapidly communicated to theentire bulk of that dough, which he intends to convert into bread. It is no longer, however, by the addition of a little leaven that the modern baker produces the commencement of his process of decomposition ;\ for there is a particular substance which he has discovered to possess the property of exciting fermentation in dough with a still greater degree of rapidity. This is yeast, or the frothy scum which is thrown up to the surface of a brewer’s vat, soon after the saccharine infusion has passed into a state of active fermentation. Of this yeast, which is a very complex and impure substance, chemists are not perfectly assured which constituent it is that spreads decomposition among the dough ; although there now seems to be little doubt that this is effected by its glutinous ingredient, which has itself already begun to ass into a state of decomposition. ° ‘When the baker proceeds to the preparation of dough by means of the yeast-fermentation, he at first takes, generally a erased but sometimes the whole of the water, which it is is intention to employ in making the required quantity of dough. In this water, which varies in temperature, according to circumstances, from 70° to 100°; there is dissolved a certain — portion of salt, the quantity of which, however, is always less than that which will finally be required, in orderto communicate the necessary flavour to the bread: yeast is now mixed with the water, and then a portion of flour is added, which is always less than the quantity to be ultimately employed in forming the finished dough, The mixture is next covered up, and set apart in a warm situation; within an hour after which, signs of com- mencing decomposition make their appearance.* ‘The sponge begins to swell out and to heave up, evidently in consequence of the generation of some internal elastic fluid, which in this instance is always carbonic acid gas. If the sponge be ofa ~ * The substance thus placed apart is termed, in the language of the bake-house, the | sponge; its formation, and abandonment to spontaneous decomposition is termed setting the sponge ; and according to the relation which the amount of water in the sponge bears tothe. whole quantity to be used in the dough, it is called quarter, half, or whole _ Sponge rye aa 166 Dr. Colquhoun’s Essay [Serr. semi-liquid consistence, large :air-bubbles soon force their way to its surface, where they break and dissipate in rapid ‘sueces- - sion. But where the sponge possesses the consistence ‘of thin dough, it confines this gaseous substance within’ it; until it dilates equably and progressively to nearly double’ its original volume, when, no longer capable of containing the’ pent-up air, it bursts and’subsides. This process of rising anid falling alter- nately might be actively carried’ on and frequently ' repeated during twenty-four hours, but experience ‘has taught the baker to guard against allowing full scope to the energy of the fer- mentative principle. He generally interferes after the first, or at furthest-after the second or third dropping of the sponge, and were'he to omit this, the bread formed from his dough would myariably prove sour to’ the taste and to the smell. He therefore, at this period, adds to the sponge the remaining proportions: of flour-‘and water, and salt, which ‘may be necessary ‘to form the dough of the required consistence and size; and ‘next incorporates all these materials with the sponge by a long aad laborious course of kneading. When this process has been continued until-the fermenting and the newly-added flour “have been intimately blended together, and until the glutimous * particles of the flour are wrought to such a union and consist- ence, that’ the dough, now tough and elastic, will receive the smart pressure of ‘the hand without adhering to it when with- drawn, the ‘kneading is for a while'suspended. The dough is abandoned to itself for a few hours,’ during which time it conti- nues in a State of active fermentation now diffused through its whole extent... After the lapse of this time, it’ is subjected to a second, but much less laborious kneading, the object of which is to distribute the gas engendered within it as equably as possible We sate: are entire constitution ; so that no part of the dough ‘may forma sad or ill-raised bread from the deficiency) of this “earbonic acid gas, on the one hand, or a too vesicular or spongy _ ‘bread from its excess, on the other. After the second kneading, the dough is weighed out mto the portions requisite to form the ~ kinds of bread desired : these portions of dough are shaped into loaves, and once more set aside for an hour or two in a warm situation. The continuance of fermentation soon generates a sufficient quantity of fresh carbonic. acid gas, within: them: to expand each mass to about double its former volume. T are now considered fit for the fire, and are finally baked into loaves, which, when they quit the oven, have attained a‘size nearly twice as bulky as that at which they entered it.’ It should be remarked that the generation of the due quantity of elastic fluid within the dough has been found absolutely neces- sary to be complete before placing it im the oven; because, as soon as the rer is there introduced, the process of fermenta- tion is checked, and it is only the’ previously-contained air, 4826.] onthe Art of Baking Bread. 167 which, expanded by heat throughout all the parts of the entire system of each loaf, swells out its whole volume, and gives it the piled and vesicular structure. When it is recollected, that the gas thus generally expanded has been previously distributed by the baker throughout the bread, and that the whole dough has been by kneading formed of a tough consistence, the result becomes apparent that the well-baked loaf is composed of an infinite number of cellules, each of which is. filled with carbonic acid gas, and seems lined with or composed ofa gluti- nous membrane; and it is this which communicates the Tight, elastic, porous texture to the bread. ) Such is the mechanical history of the most ordinary and common process followed out by the baker in making a moderh loaf. There is nothing of peculiar attraction about it, but the want of this is amply compensated by the interest. which a chemical examination into the natute and principle of the fermentative process, as here exhibited, excites. This is an investigation which has at different times attracted a considera- ble share of the attention of several chemists. . Their opinions, as will soon be found, have been extremely various in regard to almost all its details. But among the latest. writers on the subject, there may be remarked a greater coincidence of views, a sounder and more consistent solution of the different phenomena which present themselves, and a gradual tendency towards unanimity of sentiment,on the most important topics., How far the experiments about to be detailed may be calculated to further so desirable a consummation, as the exposition of a chemical theory explaining satisfactorily all the details. of the fermentative process in the art. of bread-baking, cannot be here decided. At all events there has been the greatest anxiety,:on, the one hand, to avoid every thing uncandid in the statement of ‘any opinion that is combated, of which it has been necessary to mention several; and on the other, to advance nothing strained, in support of any view that may be defended-in the following poner. If there be any erroneous statements, they have not een wilfully made, and will be corrected as soon as pointed out. With this, explanation we proceed to our chemical inquiry. : paid I, Of the Nature of the Panary Fermentation. There are three principal constituents of all wheaten flour ; starch, which exists in the largest proportion; gluten; and a saccharine principle, About thirty years ago, when the ideas of chemists regarding the elementary constitution of organized substances were less precise than at present, the difficulty of assigning to fermentation in dough a place under any.of the three. usual classes of the vinous, acetous, and putrefactive fermentation, led to the conception that it was a species of ' * 168 Dk. Colguhcun's Essays: «Si. decomposition) enteely atm It was accordingly denomi- nated Panary, and held to consist m the simultaneous decompo- sition and mutual re-action’ of all the constituents | of: flour, Subsequently to that period, the action of the fermentation has been held not to take place at once upon all the constituents of flour; but has been limited at one time’ to the glutinous’ ingre- dient, as by the Messrs. Aikin, in theirexcellent:Dictionary of Chemistry,* and at anotlier to the'starch; ‘butvof late,'the pre- vajling opinion has been that the only ‘principal! subject. of’ its action is the saccharine constituent. ‘It is the latter theory which is to be maintained in this Essay ; the fermentation tin dough, so far \as it is useful to the baker, being ascribed solely to. the: resolution of) the saccharine principle of the flourimto carbonic acid and alcohol, in consequence of its bemg brought into a situation predisposing it to pass into the vinous fermenta- tion. Undoubtedly, if the saccharine fermentation be ‘suffered to exhaust itself in any dough, it will be found that a mew fermentation, of a different kind, will succeed it; but/it-is this latter decomposition alone which is conceived to be injurious to the -bread, while the former is the source of all the benefits which the best fermentation is found to confer. It appears, therefore, that the first material point to be determined, in the chemical history cf the bread-fermentation, is, whether the saccharine principle be truly the exclusive subject of its operation... | ue Bi? aT oi Imorder to illustrate:this fundamental point, let it be first-of all considered what are the only other constituents of wheaten flour besides the saccharine principle. These may be correctly enough stated to be starch and gluten; for the albuminous and gummy principles, both from their small amount and from other ‘circumstances to be hereafter adverted to, seem to be of little influence on this question, Let the well-known phenomena of pe aati as occurring in each of these two bodies taken separately, be attended to.. They will be found to differ very reesriatit from those which take place in the panary fermenta- ion. » And if the characteristics marking the decomposition of the remaining ingredient of flour, the saccharine principle, be compared with the acknowledged appearances ‘and effects of . that fermentation which does take place in dough, their simila- rity, or rather identity, would seem to leave little room for doubt on the subject. i | | Legit _ Ho.,the first place, with regard to starch and gluten. There is no tendency to undergo any decomposition whatever induced in starch, by merely exposing it for a few hours to the moderate temperature Ry in the preparation of dough ; and even moist gluten, in the short aed necessary to commence and: complete 5) Fe Article, Bread. Published in 1807, 1826.]) ‘onthe Artvof Baking Bread. 169 the fermentation>of. dough, would: sustain: no change in. its appeanance. or.chemical. properties, though. exposed, either per se, or mixed) with yeast, to the temperature just mentioned ; yet)thefenmentative: process in dough is strong and active under these very circumstances. Besides, it is certain, that if sponta- neous decomposition either of the starch or of the gluten, always of comparatively tardy.excitement, were once commenced and left unchecked, in, circumstances so favourable to decomposition as; in the baking process, with respect, to: both moisture and temperature, it, would of necessity continue proceeding, with -vegulan,and unabated energy, so. long. as a particle of. either substance remained.unaltered.,, But.in dough, though ferment- ationycommences soon after the mixture of yeast and hot water with the flour, and goes on actively and in full vigour fora given period, varying from 24 to 48 hours, it suddenly stops short, while yet itis quite obvious, that wuch of the starch and of the gluten remains untouched. Inj fine, it may be mentioned, as conclusive of this: question, that when fermentation has thus ceased in dough, either the.addition of fresh yeast, nor-of fresh starch, “nor of fresh gluten, nor of all the three combined, has the - smallest effect in renewing the process.of fermentation. Andi it has been ascertained by.M. Vogel, that in baked bread, there exists pretty nearly the same quantity of gluten as in common » wheaten flour, and. that of the starch, three-fourths remained entire; while the other fourth had only been converted into a gummy matter, similar in appearance and properties to torrefied starch, a| chaage »which, it, 1s almost unnecessary to mention, could. have no, effect, in infusing a gaseous body into the bread, It seems, therefore, to be a point scarcely admitting of addi- tional, proof, that it is neither the starch nor the gluten which is concerned in the ordinary fermentative process, which takes We are too little acquainted with the chemical nature of the albuminous and gummy principles which ‘are found to exist, in a minute proportion, in wheaten flour, to be able to reason, ‘with equal precision, on the changes which they may undergo, or the influence which they may exert in the fermentation of dough. But besides their very trifling amount, there exists ‘this strong probability of their remaining entirely quiescent, at least during the early stage of the fermentation of the dough ;—that neither albumen nor gum appears to possess a greater tendency to pass into a state of spontaneous decomposition, than gluten on the one hand, or.than starch on the other. | If we, now. turn to the other principal constituent of flour, the — saccharine principle, a very simple solution of the difficulty will appear, and sor BUNT) AGO UE of the common fermentative _process be obtained. Seek fee mw wit a ‘And here one can scarcely avoid expressing a: certain: degree 170 _ Dr. Colguhoun's Essay (Serr. of wonder how i nen nai ae of these consider- distinguished, formerly attributed. so; great am agency, to oe malo gluten inthe i nisi voi tay 50. many prominent and apparent discrepancies, as have lately been adverted to, stand opposed to their conjecture; ».,But,in’ point of fact, a strong idea then prevailed,, particularly in-the case of the Messrs. Aikin, that the saccharine, matter .in flour is far more minute and immaterial than, it.is in,reality,, \Of course, the alcoholic fermentation, of sugar has, long, beew well known and understood, and perhaps the principal. difficulty that, ever attended the supposition of its operation, was to find room forits existence in the constitution of dough. eed at ydguat _ But.the amount.of saccharine matter naturally contained in all.flour is by. no means insignificant; on the contrary,. it is amply, sufficient to furnish in its decomposition all that quantity of carbonic acid gas, the development of which marks, the progress of fermentation in dough. Thus M. Vogel, on analyz- ing. two.specimens of ordinary wheaten flour, obtained, the following results. From the flour of the Triticum hibernum, Lin, : S54 SOD: a. 'ss 5 Kia ig bnod id KR A: APD RAS HA JOR Te erieoh OM : sof ‘es 3 Moist GlULEN 6 5.6 5 0.41454 oi¥lem spies eile HERI SaCO sit ty! f oe Mucilapinous SUgAL, 40> <4 666 49 844515, OFY Hoitibhi em Waretabte albnehen, batten da. ited ah bis on 1k BSeTVAl Bins, ; PRY {le ae Pio! 1}, GF ye ga 913311 8 10 And from the flour of the Triticum Spelta which differs only in being considered of a superior quality to the preceding : fiibDB eta aeewmar - "© t “ ‘ J ’ >f° ed 3° TSE ATV j £2334 offi »SAS9 EO ree, we ae “sees eoenvesr eee 74:0 wo eA KOs tht Deu i i" man alr ciy Dts 23-0" 99 cat it , “Moist gluten oP ti 4 9 0G SGC OS 0 6 me qe 8.2.) Tt ge Feit HO RGTS* “Micilaginous 80gare ieee see see aee OO “82 903 Vepetable albumen. ... see seeecete ee, OOM Maton * Proust, and Edlin;t have'also made experiments which'lead to'thé-‘same' con¢lusion; the latter, in’particular, found that by | merely washing wheaten flour with water, and then purifying the mucilaginous éxtract, he obtained 14 percent. of crystalliz- able sugar. The properties which Mr. Balin ascribes to the : ; Avs ’ + ® Journal de Pharmacie, iii. 212 redyies + He ascertained 100 parts of wheaten floar'to be composed ‘of about’ Starch . eee ree eee eee eee ew eeeee nde ven® eereene 44°5 : . GI. 5 pd Winaggekb bev auebinel Meas akes ed eee Gummy and saccharine extract .........0000se00 120 A YOMOW. POSH. 056s oi ec ss ok ieee scene soe ee #2"4F0 ‘ 1000 (Ann. de Chim. et'de Phys. v. 340.) + In his Treatise on the Art of Bread-Making, p. 50, He gives the following state- wWierit as the result of his exatmination of a pound of wheat : 1826.] on the Art of Baking Bread. 171 sugar of flour thus obtained by ‘him differ, however, so widely from ‘those which it has ‘been found to possess ‘by other and more-skilfulchemists, that it must’ be confessed, it seems neces« sary | to veceive’ this part~of his’ ‘statement with considerable qualification 99/609 80h oF bem 82) Ligeikv be Bos _ Bimee ithe presence of\a saccharine constituent in flour is thus clearly established)’ and that'to no inconsiderable extent, bein not) less‘than; tothe amount of five per cent. according to the several! analyses just’ quoted; and ‘since the alcoholic ferment- ation'‘of sugar is one of perfect familiarity to the chemist, the characteristics of which correspond with the fermentation in dough, m the rapidity with which it commences, the ‘activity with which it continues, and considering the usual amownt of the sugar, the period during which it lasts, there would seem little'room left to doubt wherein consists the true fermentation which occurs in the art of bread-making. © =. ee But the results of ‘the following very simple’ experiment, which has been repeatedly performed with the same success, would'seem still further to settle the point, and indeed to'place the matter beyond the reach of controversy. After suffering the fermentative process to exhaust itself in a mass of dough, and the dough to be ‘brought into that situation in which the addition of neither yeast, nor starch, nor gluten, had produced auy effect on a sinnlarly ex-fermented mass, I tried the renewal of a little yeast, to the dough, along with a small, addition, of the other constituent of the flour, the saccharine principle. On adding common ‘refined-sugar in these circumstances to the amount of four per cent. the process of fermentation immediately recommenced, and in its appearance, activity, and duration, was just a repetition of the previously-exhausted process) of fermenit- ation. After a lapse of about the same period, it, mm the same manner, totally ceased. Its difficult not to look upon. this experiment, especially when taken in connexion with the others lately stated,.as ¢om- pletely decisive of the question, that the ordinary bread-ferment- ation is. the simple and. well-known process. of the’ aleoholie fermentation.of sugar. If any thing could. be added, to confirm this, it is the fact, that the mere addition of sugar, as above, to an ex-fermented mass, without being coupled with any other substance, produced. a.renewal of the process of fermentation in the dough. In this case, however, as might have been expected Oz. Dr SEY i ins pwns via ws secre e Peed UA ibe 1000 Bran. . 02 BAG GUI 60 6 eo -cre-v-oe 0 cade eteees PNAS CU HSENS « 0 6 ¢ AE a) vee eben ‘ ° 0 2 _ Loss in grinding. ...+...eceeess divin dank eee he Orrew 5 swig 172 Dr. Colquhoun’s Essay (Serr. from the comparative weakness of the yeast, the spontaneous decomposition was more tardy’in commencing; less brisk ‘in its operation, and lasted longer than’ in ‘the ‘ordinaty proteds ; but this, as is well known, is! precisely what invariably takes place, when saccharine matter is brought ‘into a staté of fermentation by means of a ferment which 1s: already’ either half-exhausted, or whose fermentative power is naturally feeble,97°"'" 6 '9 2°" There seems to’ be. but ‘one objection to the ad i fa theory, which is supported ’-by ‘proofs’ so very strong as these just mentioned, and that objection is more apparent thin 'réal. After a loaf is baked, there is found still to exist in its ¢ompo- sition almost as great a proportion of saccharine matter as occurs inthe original wheaten flour, previously to fermentation. M. Vo- gel Seat that in a baked loaf there remained '3*60' of sugar, which, was only 1 or, 1*5 per cent. less than had existed in the flour before making it into dough.* And he’ very naturall declares that he was not a little surprized by the fact, as he held the same opinion on the subject of the fermentation in dough, which has been supported in this Essay. (96% wo »But it must, in the first place, be recollected, that in every loaf, as the process of fermentation has been invariably checked ata very early period by the baker, that constituent, which was the subject of the fermentation, can never be wholly, and’ will often. be- but -very partially, decomposed. And in addition to this. it, seems almost) certain that “another and a sufficiently interesting, chemical change occurs during baking, ‘and which, if the, following account be correct, will easily reconcile ‘the large amount of sugar found to exist in bread after baking, with the fact, that the saccharine principle! ‘was nevertheless the subject of all the fermentation which had taken place. tau _In the experiment of M. Vogel last referred-to, besides ascer- taining the amount of ey to have been scarcely affected by baking, and three-fourths of the starch to retain their properties unaltered, it appeared that the remaining fourth had acquired the properties of a gummy matter, analogous to torrified starch, being readily soluble in cold water. Now the experiment to be detailed seems to point strongly to the conclusion, that when any part of a loaf of bread enters the oven in the state of gelati- nous starch, the process of mere baking alters the relative con- __ * In 100 parts of loaf-bread, prepared with wheaten flour, distilled water and yeast without the etictaie of any common salt, he found the following ingredients : x Sugar. ....-.sercsicsscecsecee 1 0 Se vectleepeuee 3°60 Torrified (or gummy) starch .....-.++¢e0er0'~ Several masses of dough. were prepared, in which pure wheat- starch was mixed)with common flour, in very various propor. tions:, In some of the pieces, this starch had been gelatimized, with a minimum of .hot.water, before/it was added tocthe flour.’ After.a proper allowance.of salt to each separate mass of dough, -and a.thorough kneading, the whole:were set apart for the ordix’ nary, period, and. allowed to ferment to the usual. preparatory” extent, after which they were baked in:the oven. In respect of: outward appearance, the increase of volume, and the’vesicula-' rity, of their internal structure, none of them varied materially! from.a piece of common:loaf baked along with ‘them: forthe’ purpose of comparison; at least, the only difference was that: when the starch originally, added to the dough very materially’ exceeded'the proportion of common flour in the same piece)'the ' loaf, while it was decidedly whiter in appearance, had not-risen so well, nor did.it possess a structure so vesicular asthe others.’ But on. tasting the bread of each: loaf, the unexpected result. was perceived, of the existence of unusual sweetness distinctly’ observable in all those. loaves. which had contained the largest’ PER PROBE ce gelatinized starch. ‘The other: loaves, where! smaller quantities) of the gelatinized starch had:beenemployed, or where pure, but dry, pulverulent starch had:been used imany prapru dite (oven all were;made atthe same time, «and, mixed: with flour of the, same; quality, had no. sweetish: taste! whatever® to distinguish them from..common bread. ‘These faets:\ led, therefore, to. the conclusion, that the presence ofigelatinous’ | starch in bread when put into the oven, is ameans of forming: a® certain amount of saccharine matter within the loaf; during-the» process of baking. .And:as.it is probable that gelatinized starch does exist more or less in all loaves which have beenfermented> by.our usual process, it would appear that in every: case there’ is formed, while in the oven, a‘certain portion of sugar within: the bread. . The difficulty, therefore, which suggested itself to» ' M. Vogel, if indeed, it be not accounted for by the early period at which. fermentationis interrupted in bread-making,seems thus to be completely removed; and the alcoholic fermentation ‘of the saccharine. matter in flour is sufficiently proved to be the true panary fertientation occurring ‘in our ‘ordinary system of bread-making. The point may therefore be assumed.as scarcely: admitting of further question, that it 1s the saccharine principle of flour in which decomposition commences, and ‘with which it ends, while dough is under fermentation. aS | The first step of the investigation into the nature of the panary: 174 Dri Colgulioun's Essay > | (Serr. fermentation being now ‘satisfactorily gained: in ‘the establish-. ment of the precise subject of its exclusive, action, ‘the atext: important matter is to ascertain whether this fermentation-be: truly sui generis, or to which of the’ fermentations, the vitions, the acetous, or the putrefactive, does it: iSvob euds biog » -That which first commences: within: the ‘baker's doughy pro- vided it be of ordinarily good quality, is certainly the common: vinous or alcoholic: fermentation, ‘This is: plas from theofact already stated, that the appearances of the vinous fermentation: ofisimple sugar, resolving itself into alcohol.and carbonic ‘acid, are precisely the same with those which, in: the: process’ of fermentation, as it is usually: conducted: in the bake-house;. occurin dough. Buta remarkable change: in the character of the panary fermentation is always found to occur if it be allowed to: proceed far enough; and as this change, whenever. it super- venes, has the effect of injuring the quality of the bread, and is accordingly the dread of the baker, itis material to inquire into the:nature of the secondary alteration, which, at a certain stage: of-advancement, will always take place. . iW drs ‘Rhe: mode in which the new substance shows: itself,, when enerated: in: this: subsequent fermentation of the dough, is»per~ ectly well-known to the baker. Fermentation may, with good materials, and in ordinary circumstances, be easily carried on by: him, to the: extent requisite to:produce a light and well-raised loaf, which yet shall be sweet and pleasant to the taste. Buthe iss welkaware that if he do not check the fermentation of’ his: dough: in due time, it becomes invariably sour, and the sourness increases in proportion as the fermentation has been allowed to pass its proper limit. It is only from practice, however, which teaches him to judge by appearances, that’ he acquires the art of distinguishing the moment when his interference becomes necessary to stop the process of fermentation, and the conse- quent generation of acidity. | Li The source of the formation of this acid has been ascribed at different times, and by different chemists, to each of all the several ingredients of flour; to its gluten, its starch,’ and its saccharine principle. There appears now, however, scarcely any room left for doubting, that the greater portion of it, at least, is invariably the consequence ofa second fermentation; and that it is produced by the very familiar process of the-acetifica- tion of the aleohol which had been developed im the original fermentation of the saccharine: principle. Phat the starch, or even the gluten, should ever contribute ‘to its ee extremely unlikely, at least in the ordinary routine of /bread- making’; although there are reasons for suspecting, that in those cases in which the sponge or dough has been too long kept, or in which the fermentative process has been im other respects unskilfully conducted, a. portion of the albuminous and mucila- 1826.) on the Art of Baking. Bread. 175 ginous) principles: may: likewise pass into, a state of acescence,; and.so contribute towards the activity of theacetous fermentas” tion. noitsineda) ard "ae ARV RE itor dpe Pie re ‘BIO CO It:has been universally taken for granted.among authorsy that the acid thus developed.in dough is exclusively: the acetic:> And when we-reflect. on: the facility and) frequency with: which«this principle» is formed. during the decomposition of organized: mat» ter, and,on the abundance of materials which are in this instance afforded -for its, production, we: must admit: that it! generally © constitutes ithe chief principle of» acidity. in sour dough: Perhaps, however, it.is rarely the sole cause of this acidity; for: there seem. good: grounds. to conclude that another acidofie more fixed mature, most probably the lactic, becomes notwunfrea> quently associated with it; particularly when the fermentation ' of the dough has been more. tardy than usual, in consequence ' either of the: imperfection of the yeast, or of the original bad’ quality,of the flour. It has been proved, of late, by the experia ments-of Braconnot, Vogel; and others, that this acid is gene-': rated with much readiness, and. toa considerable amount; during: the. spontaneous decomposition of a great variety of vegetable substances when in a state of humidity. | And: the ‘presence: of’ lactic acid, would account fora remarkable circumstance com nected; with the acescence of dough, of which) it is difficult:to: suggest.iany other explanation, and: which occurs: inva most — striking manner in. those cases, where fermentation has! beew | allowed to run: on: to, great. excess. This is the fact; thatthe: acidity of unbaked dough in this condition is greatly: more pera ceptible to the. palate: than: to the olfactory nerves, while the: sourness. of, the same: piece,of bread after coming» out; of they oven;,is, on the contrary, much more offensive to the smell thaw: to. the taste. . Now this is precisely what might be expected: to: happen, if we suppose that lactic acid contributes, im conjunce' tion with the acetic, to produce the acescence of sour dough: At the ordinary temperature of a bake-house, the former acid, although very perceptible in the mouth, is not» distinguishable by the: nostrils; but .as, it: is easily decomposed by heat, no» sooner is it-exposed to the high temperature of the oven, than, as has been proved: by. the experiments of Berzelius, it:is, inva: great measure, resolved into the acetic acid, and so. becomes. more:palpable to the sense of smell, and less. so to thatof taste. It: would appear, therefore, from what has just been stated, to: bea pretty-well-established point, that in acescent dough, a second, decomposition has always come. into play ; that this: is’ probably at first of a mixed character, and consists partly of the» resolution into acetic acid, of the alcoholic principle ‘previously developed -by the saccharine fermentation, and partly ofthe formation of lactic acid ; while:the heat of the oven,!which checks the saccharine fermentation, at the same time decom- 176 Dr. Colguhoun’s Essay. {Serr es at least great part of the lactic acid, and resolves it also into the acetic. | 1 SOD Om amas This theory seems to explain satisfactorily all the leading’ a accompanying the progress of fermentation in aker’s dough, ‘and also to account: for some of its results as’ appearing in the progress of baking, which do not admit easily of any other solution. Thus it appears that the ‘subject of the bread-fermentation in common practice, is, in every case, exclu- sively the. saccharine principle of. flour. That the kind of nary fermentation is by no means peculiar, but always in the: Fret instance the common vinous or alcoholic fermentation of sugar, accompanied as usual by a copious evolution of carbonic acid. gas. That after this has gone on for a certain length of time, a second process of spontaneous decomposition com- mences ;. the alcoholic principle lately extricated ferments, and is resolved into acetic acid, at the same time that, in all probabi- lity, a considerable portion of lactic and acetic acid is generated at the expense of certain other ingredients of the flour, which, at the commencement of the fermentative process, had remained: uiescent ; and it seems not improbable that a contemporaneous rmation of ammonia in the: dough takes place to a certain extent. It has been already stated to be an ascertained point, that the lactic acid is frequently produced by the spontaneous decomposition of a vegetable substance, when exposed in a state of humidity to a moderately-warm temperature; and besides, the existence of this acid seems proved by the change pro-. duced by baking sour dough, in regard to the organs by which: its acidity is perceptible before and after baking. : | - But if that acescence which always injures so greatly the quality of the bread in which it occurs, be truly the result of a second process of decomposition, the materials for which are only furnished after the first process has been carried on toa considerable extent, it becomes obviously. the secret of the baker’s art to interfere and check the progress of fermentation in dough, while yet it is confined to the simple process of saccharine decomposition, and before the resolution into acetic acid of the alcoholic principle thereby evolved begins. Indeed that may be defined to be good bread, in which the fermentative process has been so regulated and checked; the art of doing which cannot of course be otherwise acquired than by expe- rience. But there are other methods, and these extremely simple and effectual, for enabling the baker to adopt measures’ either to prevent or to correct the evil of supervening acidity, and to them our attention will now be shortly turned, before concluding this general view of the several operations and changes in the most common system of baking bread. | We have already spoken of the nature of the process which generates acidity in fermenting doughs, an inconvenience too 1826.] on the Art of Baking Bread. 177 often felt by every baker to be unknown in the experience of almost»any:-bread-consumer in the country. | Against..this mischief, it scarcely seems that the utmost skill or precaution that can, in the present state of the art, be employed, is suffi- _ cient-tonguard. For if the flour has been orginally of bad quality, or if the yeast employed be of a weak or indifferent sort, or if the water be added at too high or too low a tempera- ture, or perhaps, also, if the state of the atmosphere be not favourable, the: dough may speedily be found to become -acescent. In short whenever the second process of decomposi- tion commences within dough, before the vinous fermentation of the saccharine ingredient has proceeded far enough to evolve the required quantity of carbonic acid gas, then the bread can not, by any means at present used, be made to possess the quali- ties of lightness and sweetness joined. The one of these. can be obtained only at: the expense of sacrificing the other; for the baker must either, as soon as the incipient acescence appears, send his dough to the oven, and obtain in return a sad and ill- raised loaf, or if he prefers, as is generally done, to have it light and well-raised, and therefore allows due scope to the fermenta- tive process, the bread will certainly be sour. There is, however, a very simple and a very complete cure for this evil, a method by means of which, even after acescence shall have decidedly commenced, the baker may nevertheless be enabled to remove it entirely without sacrificing the valuable object of the vesicularity of his loaf. The remedy to be applied in order completely to neutralize an acid, as will at once suggest itself to every chemist, is the due exhibition of an alkali. And it is a striking proof how much the mechanic has been accus- tomed to plod,uninquiring and uninstructed, over the same ground, in past times when he was less familiar with science than he is likely now to become and for ever to continue, that a relief so obvious and so simple, from inconveniences so excessive, should at this moment remain unknown to the greater part, if not to all, of the bread-manufactories in the country. The use ofa little of the carbonate of soda, or of the carbonate of magnesia, is all that is required in order to secure to the baker a dough. which he may always have sweet and pleasant during the entire progress of fermentation; and even in case he may have allowed acidity to supervene to no inconsiderable extent, the same alkalies may be successfully and innocently employed in restoring dough to its original freshness. In order to bring the matter fairly to the test, and to try the effects of the system here spoken of, a quantity of ordinary loaf- dough was taken, when just fit for the oven, and set aside ina warm. situation, where, of course, the fermentation briskly proceeded,, To the simple saccharine decomposition was soon added. the secondary process of acescent fermentation, and the New Series, vou. X1l. N 178 — : Dr. Colguilioun’s Essay [Serr. dough became gradually sour. At the expirationof twenty-four hours, upon opening up the dough, which was:still in a state of strong fermentation, a very acid odour was plainly perceptible: The taste was also distinctly, though weakly acid. After taking two pieces, weighing five ounces each, from the general mass, it was once more set aside. Into one of the portions thus. chosen were kneaded 10 grains of the common carbonate of magnesia, and then both were, after the usual manner, baked in the oven. The difference between the two loaves, when baked, was most striking. The bread which had been made fromthe sour dough alone had a taste distinctly perceptible of acidity, and asmell so sour as must have rendered it almost unsaleable, while that which contained the magnesia presented not the slightest indi- cations of any kind of sourness, and appeared in all respects an excellent loaf. . | This was certainly a very decisive proof of the advantage with which this carbonate may be employed in correcting an acidity, which had proceeded to as great a degree as it is ever met with by the baker in his ordinary practice. But it appeared desirable both in a practical and in a theoretical view, to try the effect of the same substance on a still greater degree of acidity, and also to compare its relative action with that of carbonate of soda on the same acid. Accordingly that mass of sour dough from which two portions had been taken, as above-mentioned, was allowed. to remain for twenty-four hours longer in a warm situa- tion as before. At the end of this period, the various processes of internal decomposition had not wholly ceased, and it was found to be still in a state of fermentation, though not so vigo- rous as on the preceding day. The acid taste of the dough had by this time very much increased, and the acid odour was strong. Four portions of this dough were now taken, all of which were baked after the usual form; but with this difference in their composition, that one was put into the oven made of the sour dough just as it stood, a second had four grains, and a third eight grains of the carbonate of magnesia kneaded up with them, and to the fourth were added 16 grains of the common crystal- lized carbonate of soda. The first loaf, when baked, possessed, | in a very rank and strong degree, both a taste and a smell of acidity. In the second, the acidity remained faintly perceptible, especially in the smell. In the third, the loaf had no acid or . other disagreeable peculiarity whatever. In the fourth, there was no acid taste, but a shanty acid smell. yt These results appear quite decisive. For thus the exhibition of eight grains of the carbonate of magnesia to five ounces of dou h, er about 32 grains to the pound, which is about 52 grs. to the pound of flour, proved amply sufficient to correct an acidity which had been allowed to proceed to an extreme hardly ever known in practice. And indeed in the great bulk of 1826.] on the Art of Baking Bread. 179 instances a much smaller quantity would be found completely sufficient; so that, in ‘all probability, three ounces of carbonate of magnesia to every 100 pounds of flour would be found to serve the purpose, provided a due incorporation were effected of the magnesia throughout the substatice of the bread. | ‘The employment of the carbonate of magnesia in thus correct- ing the acidity of dough, appears to possess decided practical advantagses when compared with the use of carbonate of soda. It has a remarkable bulkiness and elasticity, so as, when employed in excess, to produce éven meclianically a consider ' able effect towards the lightness of the bread into which it enters. And it may be remarked that these qualities, together, perhaps, with its tendency to correct acidity, although this latter seems to have been less regarded, caused it to be recom- mended by Mr. Edmund Davy,* as well adapted for raising and improving the sad and doughy bread which was made from the bad flour of harvest 1816. But besides possessing these advan- tages, itis also more tasteless, and a less active chemical agent than the carbonate of soda. Accordingly, whenever the acid to be corrected happens to exist diffused through the sponge or dough, as it may be difficult by any care in kneading to incor- porate the alkali equably with the whole mass, it is safest to use magnesia, as an accidental éxcess of that substance occurring in any part of the bread, will neither materially injure its flavour, nor will any activity of its alkaline powers induce a chemical change upon any of the constituents of the flour. But it may be proper to observe, that whenever the baker is led, by any circumstance, to anticipate the supervening of acescence in his dough, while yet the materials of it are unmixed up, he will do well to mingle the magnesia with the flour before either is wet, and he may thus rest secure that the salutary neutralizing effect of his corrective will be called into action throughout his dough, precisely in proportion as it is required. Its presence being thus extended through all the particles of the dough, no sooner will any acid be generated in any quarter, than it will be neutralized by the alkali. The small quantity of neutral salt which is formed by the mutual action of these two bodies does not appear at all to affect the quality of the bread. And so far from this employment of an alkaline carbonate tending to pre- vent the loaf from rising, wherever that substance is truly called into action, the carbonic acid eas evolved in consequence of on neigh materially promote the vesicularity of thé read. It is not only, however, from the fermentative process in the dough that the baker has to apprehend the misfortune of sour bread ; for it sometimes happens, though now more rarely by * Philosophical Magazine, vol. xlviii. p. 465. \ oe RES 180 Dr. Colquhoun’s Essay | (Serr. far than in former times, that the yeast becomes sour in the bake-house before it is mixed with flour at all. The remedy for this is, as may easily be supposed, of the same nature with that which has just been described.. To leave no doubt upon the matter, it was subjected to the test of actual experiment, and the results were as decidedly in favour of the good effects of employing an alkali as could Poebly have been anticipated. Even after the yeast had been allowed to stand over for an entire week in a warm situation, and had thereby acquired such a concentrated acidity as entirely concealed its taste and smell, the addition of an alkali had the immediate effect of restoring the natural yeasty flavour. It is only necessary to observe, that, in such a case, the alkali should be added just so long as an effervescence is thereby produced, and no longer. When sour yeast had thus been corrected, it appeared in practice to possess the fermentative principle in unimpaired activity, and to be capable of being employed in a baking process with the same success as yeast entirely recent and fresh. There seems then to be nothing more easy and nothing more effectual than the application of this corrective of acidity... Itis only surprising that an inconvenience so annoying and disagree- able, should have till now been tolerated by all classes of people, when a simple remedy lay so close at-hand. The earlier portion of. the process of bread-baking has now been discussed ; we have briefly detailed the mechanical prac- tice of the baker, and have offered a chemical explanation of the accompanying phenomena. And although the suggestion of a remedy for the mischief of supervening acescence, has proved a somewhat lengthy episode in the history of the loaf, yet it seemed a matter of too much importance to be more slightly passed over. It has now been pretty fully considered ; and after the process of preparing bread for the oven has been thus examined in detail, we proceed to examine what changes are the results of baking in the oven. | ; The true nature of these alterations remains as yet involved in very considerable doubt and uncertainty. The first striking effect observable, is, that however active may have been the state of fermentation previously at work in the dough, before being exposed to the fire, it is immediately checked and brought to a period. But it has scarcely been yet determined what is the precise action upon the constituents of the flour which follows, and we shall now rather enumerate than discuss in detail the. various alterations which mee occur. It would appear.to be the amylaceous ingredient which is the subject of the greatest subsequent change. Ithasalready been stated as pretty certain that there does also occur in the oven the formation of a saccharine matter at the expense of any gela- tinized starch which may have been formed during the early 1826.] onthe Art of Baking Bread, 181 preparation of the dough. M. Vogel has further ascertained, in an experiment already quoted,* that about one-fourth of the whole quantity of the starch had been converted into a gummy matter possessing the characters of torrefied starch, and which, like it, was soluble in cold water. The gluten also, though little changed in amount, as the experiment of Vogel shows, is certainly so far affected, while in the oven, as to sustain a disunion of its particles, and to be thereby deprived of much of its adhe- siveness and elasticity. But of the nature of these alterations, little further has been determined. When these several changes have taken place, when the bread has gradually swelled to about double its bulk in the oven, and has acquired its upper and under crust, or, in other words, has become slightly torrefied in those parts which are immediately exposed to the high temperature either of the glowing floor or of the heated air of the oven, the loaf may be withdrawn, and requires only to be thoroughly cooled in order to exhibit a fair specimen of the perfection to which the modern art. of bread- baking has been carried. Although it is, perhaps, impossible to assign with unerring precision to each of the several consti- tuents of flour its peculiar function, and to each detail of process its precise effect, towards completing the perfect result of a well- made loaf, yet it may be a matter of some interest briefly to specify the peculiar share which the present state of our inform- ‘ation would guide us to assign to each in the system. The moistening of the flour with water and the kneading of it into a homogeneous mass, is the first step towards forming the rudi- ‘ments of the future loaf. The saccharine principle of flour, while it serves the purpose of communicating to the bread an agreeable relish, may also be with certainty regarded as the subject of that chemical fermentation which introduces carbonic acid gas into the system of the dough. Thus there is generated the elastic fluid within the bread which gives it lightness and vesicularity. The gluten of the flour, an ingredient peculiar to e the farina of that vegetable, is of use in binding and cementing all the particles of dough into one cake, by means of the mecha- nical process of kneading; besides, by its tenacity, when duly diffused throughout a loaf, it extends and dilates within the oven into a thousand little cells, to imprison the contained gas, as it _ expands by the heat. And the remaining ingredient, starch, is not only the great basis of all bread, and the main-source of nutriment in each loaf, but besides, in the oven, becoming rigid through the action of heat, it materially assists the permanent fixation of the particles of the loaf while in its most expanded form ; it is often the means of yielding a certain supply of sac- ‘charine’ matter; and there is also a considerable portion of its * Journal de Pharmacie, vol. iii. p. 219. 182 Dr. Colquhoun on the Art of Baking Bread. [Sxpr. entire mass formed into a gummy’substance. . In regard to the albuminous principle in flour, it cannot fail to undergo coagula- tion in the oven, and, in consequence of its total want of retrac- tility when thus altered, will doubtless contribute somewhat to confirm the setting of the bread, and enable it to retain that spongy vesicular texture which had been previously developed by the expansion of the internal elastic vapour. hen these several constituents of the flour have discharged their respective functions, and the various processes of kneading, fermenting, and baking, have been duly performed, the formation of the common wheat-loaf is aaaleial Such is the history of the ordinary system pursued, by the baker in manufacturing the great proportion of that valuable article, bread, in so far as it may be regarded as one of the necessaries of life.. For with respect to those kinds of bread, such as plain waéer-biscuit (sea-biscuit for example), into the composition of which no elastic fluid enters, their. manufacture may be regarded as already described, since it merely implies that nothing relative to the fermentative process shall make part of their preparation. The mode of making them is in fact one of the simplest and least interesting pieces of common cookery that can be conceived, and even if its details had not been included within the account already given of the manufacture of the common wheat-loaf, they would scarcely have merited to be separately mentioned. | There are, however, a great many products of the baker’s art, perhaps confected with spices or otherwise, which are prepared so. as to belong rather to the luxuries of civilized society, than to deserve being classed among the necessaries of life. In all these cases the same essential advantage of infusing into the bread a due supply of an elastic fluid is equally felt ; but from a variety of circumstances it may occur that the fermentative process may be ill adapted to attain that end, The-reason of this is, that by the system of fermentation, it is in vain to expect good bread, unless a very considerable preparatory delay can be spared; and if this,delay cannot be conveniently afforded, or if the more complex compound of a confected bread contains any ingredient which paralyzes the action of the ferment, the baker has found it necessary to have recourse to some other methods of introducing the elastic fluid. Many of these are sufficiently ingenious, and. although none. can be so interesting as that which is the means, of preparing the great staple of our food, yet there is much useful and curious investigation connected with the examination of a few of these processes ; to which we now proceed, . (To be continued.) 1826.] On the Magnetism arising from Rotation. 183 Articuie II. Abstracts of Papers in the Philosophical Transactions for 1825, on the peculiar Magnetic Effect induced in Iron, and. on the Magnetism manifested in other Metals, &c. during the Act of Rotation. By Messrs. Barlow, Christie, Babbage, and _ Herschel. ait (Continued from p. 116.) Account of the Repetition of M. Arago’s Experiments. on. the Magnetism manifested by various: Substances during the Act 4 Rotation. By C. Babbage, Esq: FRS. and J. F. W. Herschel, Esq. Sec. RS. : . THE curious experiments of M. Arago described by M. Gay- Lussac during his visit to London.in the spring of the year 1825, in which plates of copper and other substances set in rapid rotation beneath a magnetized needle, caused it to deviate from its direction, and finally dragged it round with them, naturally excited much attention, and the investigation of their various circumstances, and of their connexion with the effects observed by Mr. Barlow in December, to be produced by the rotation of masses of iron, and described by him in a paper read to the Royal Society,* became an object of considerable interest. Accordingly, having erected at Mr. Babbage’s house, in Devon- shire-street, an apparatus for setting a copper-plate in rotation about a vertical axis by the aid ofa turning lathe, the authors of this paper proceeded to try its effect on a magnetized needle suspended over it. The first ged failed from the use of too small a needle ; but this being replaced by a magnetic bar of considerable weight delicately suspended by a silk thread, they had the satisfaction of seeing it deviate several degrees from its point of rest in a direction corresponding with that of the rota- tion of the copper-plate ; and on employing instead of this bar a very delicate azimuth compass, belonging to and the invention of Capt. Kater, the influence of zinc, brass, and lead, was simi- | larly rendered sensible. ! | “In this first trial,” they observe, “having neither the com- mand of a very rapid rotation, nor of massive metallic discs, the deviation of the compass observed did not exceed 10 or 11 degrees. In order therefore to enlarge the visible effect, and at the same time disencumber ourselves of the limit set to it by the ' polarity of the needle, it occurred to us to reverse the experi- ment, and ascertain whether discs of copper or, other’ non- magnetic ‘substarices (in ‘the usual acceptation ofthe word) See the last volume ofthe Annals, p. 444. 184 Messrs. Babbage and Herschel on the [Sepr. might not be set in rotation if freely suspended over a revolving magnet. In order to make this experiment, we mounted a powerful compound horse-shoe magnet, capable of lifting 20 ounds, in such a manner as to receive a rapid rotation about its axis of symmetry placed vertically, the line qn the poles being horizontal and the poles upwards. A circular disc of copper, 6 inches in diameter and 0:05 inch thick, was suspended | centrally over it by a silk thread without torsion, just capable of supporting it. A sheet of paper properly stretched was inter- posed, and no sooner was the magnet set in rotation than the copper commenced revolving in the same. direction, at first slowly, but with a velocity gradually and steadily accelerating. The motion of the magnet being reversed, the velocity of the copper was gradually destroyed ; it rested for an instant, and then immediately commenced revolving in the opposite direc- tion, and so on alternately, as often as we pleased. | The rotation of the copper being performed with great regu- larity, it was evident that by noting the times of successive revolutions, we should acquire a precise and delicate measure of the intensity of the force urging it, provided we took care to neutralize the torsion of the suspending thread. To make the experiment strictly comparable proved however a matter of much delicacy, as the slightest change in the distance of the plate from the magnet was found to produce a material alteration in the time of its gyration. Our first inquiry was directed to ascertain the effect of the interposition of different bodies as screens in cutting off or modifying the peculiar rotatory effect. The substances tried were paper, glass, wood, copper, tin, zinc, lead, bismuth, anti- mony, and tinned iron plate. The metallic plates here interposed, as also the wooden ones, were circular discs of 10 inches in diameter and half an inch in thickness, the metals being all cast for the purpose, the wooden dise serving for a pattern. It was found that the various sub- stances examined exert no sensible interceptive power. Glass in like manner had no effect; but when the substance inter- posed was iron, the case was widely different, the magnetic influence being greatly diminished by one, and almost annihi- lated by two thicknesses of common tinned iron plate. When the poles of the revolving magnet were. connected by a piece of soft iron, the rotation of the copper disc. was in like manner almost entirely annihilated. Resuming now the original form of the experiment, the copper disc of 10 inches diameter and half an inch thick, was placed on the vertical axis, and made to revolve with a velocity of seven turns in a second, a velocity which it was found conve- nient to give, and easy to maintain, corresponding as it did with 1826.] Magnetism of Metals, &c. arising from their Rotation. 185 one stroke per second of the treadle of the lathe; and this velocity, unless the contrary is mentioned, is to be understood of all the rotations so communicated, spoken of in the remainder of this account. The copper-plate thus revolving, the disc of copper first-men- - tioned was suspended over it; but though at first it seemed ‘to be very slightly affected, yet on frequent and most careful repetition of the experiment, with every precaution to guard against currents of air, not the most trifling effect could be perceived. This remarkable result, while it stands opposed to any theory of magnetic vortices generated by the rotation of one body, and transferring a part of its motion to others, is, on the other hand, perfectly consonant with, and indeed a necessary consequence of the view which will be taken of the subject in the sequel. | In like manner a bar of hardened, but not magnetized steel, was very slightly, if at all, set in rotation by the revolving copper, not more than probably would correspond to the small degree of magnetism unavoidably developed in it in the act of hardening ; but when magnetized to saturation, it was made to revolve rapidly. This experiment appears decisive as to the origin of the magnetic virtue exhibited by the copper and other bodies in these experiments. It is obviously induced by the action of the magnetic bar, compass-needle, &c. on their molecules. , ~Our next ane gon was directed to the degree in which this development of magnetic virtue takes place in different metals and other bodies. For this purpose two different processes were adopted. The first consisted in securing each of the 10-inch discs already spoken of, successively, on the vertical axis of our machine (which was now fitted up more firmly). Giving them thus a rotation in their own planes, the azimuth compass above-mentioned was placed on a convenient stand centrally over each at the same distance. The deviatiuns observed, and the ratios of their sines to that of the deviation produced by one of them (copper) chosen as a standard, were as follows : (Motion of the\(Motion— retro- Ratio of the force art hee TE!" disc. direct, onl grade, or un- Mean. to that of cop- i asad screwing.) screwing.) per. ; Copper ........ 11° 30° Alo 17’ 11° 24’ 1-00 on ae 10 7 10 15 10 11 0°90. UR sai 6 bas «ace 5, 30. : .. & 12 5 2l 0°47 BONE iF 6 2h tt 2 50 2 55 2 53 0°25 Antimony...... Peal2 eae Yb 1 16 O-11 Bismuth ....... 0 6 0 6 0 6 0-01 ciao anni 0 O og... 0 0 0 0°00 | The experiment was repeated -~ some weeks afterwards), placing 186 Messrs. Babbage and Herschel onthe .. (Serr. the compass (by a more advantageous adjustment of the .appa- a hed much, nearer the revolving disc,. The results were as ollows : Name of the re-|Mean of deviations|;, ,.. » yolving sub-| screwing and un- i re a mee W : stance, screwing. re Att / © Copper. sis... ces 28° 54 1:00 t AIRCr onreeois pipe - 26. 42 0-93 ye ee 12 54 0-46 ERG cpephaewe Tn 0°25 Antimony ...... 2° 27 0-09 Bismuth ....... 0. 32 0:02 Agreeing as nearly as could possibly have been expected with the foregoing. , Of the ee metals, silver appears to hold a high rank, and gold a very low one in the scale of magnetic energy. Indeed the latter metal rendered standard by copper was scarcely more powerfully set in rotation than seemed fairly attributable to the quantity of its alloy. | int The examination of mercury peenine peculiar interest, from its fluidity, and the facility with which iron might be excluded from the experiment ; to make which a flat ring of box-wood was cemented with wax between two circular glass discs, so as to form a hollow cylinder, two inches in internal diameter, and | 0:10 in its interior height. This being suspended, empty, by a long delicate silk-thread over the horse-shoe magnet, was not in the slighest visible degree affected by its rotation, however long continued. It was then detached and filled with mereury, which, from having been thrice distilled, and afterwards having stood upwards of a twelvemonth in a bottle in contact with a solution of the nitrate of that metal, might assuredly be regarded as absolutely free from iron. Being again suspended as before, it now readily, though sige 4 obeyed the rotation of the magnet in either direction, being fully commanded by it, and set in motion, stopped, or reversed in its gyrations at pleasure by merely. continuing or changing properly the motion of the magnet. This experiment was witnessed, among others, by our illustrious President. The place which mercury appears to hold in the scale of magnetic energy was judged to A between anti- mony and bismuth, certainly superior to the latter, and certainly — inferior to lead. ' In wood, glass, wax, rosin, sulphur, sulphuric acid, water, &c, we have not hitherto succeeded in obtaining unequivocal traces of magnetism. The experiment with unannealed glass succeeded no better than with annealed. In the case a of one non- metallic body (unless a minute portion of iron present may have 1826.] Magnetism of Metals, &c.. arising from their Rotation. 187 deceived us) a decisive result has been obtained ; and, ,what is very singular, this body is carbon, in that peculiar state.in which its density, lustre, degree of hardness, and high conducting quality, both as regards heat and electricity, seem to give it some title to.a place among the metals. This is.the state in ‘ which it.is precipitated by a red-heat from coal-gas.. The mag- netism developed in this singular substance is, however, too feeble to admit of precise measurement, and is only rendered barely sensible by delicate management. 7 The second process alluded to as employed. by us to compare — the relative magnetic forces of the different bodies examined, consists in suspending magnetized bars over revolving discs of them, and observing not the point of equilibrium but the velocity generated, or the time required for the description of certain spaces; in other words, by measuring not the statical, but the dynamical effect. These methods,- for distinction’s sake, may be called the statical and dynamical methods of observation. In the original experiment of M. Arago, a magnetic needle was made to deviate or revolve by the rotation of a plate beneath it. The motion of the needle must of course be rendered irregular by the effects of its polarity, and subject to periodical accelerations or retardations ; and it is obvious, that in the case of a very weak magnetic force in the plate it can never execute an entire revolution, but. must oscillate backwards and forwards till reduced to rest by the friction. and resistance of the air. It occurred to us, however, that much more regular and uniform results might be obtained by this means, could the polarity of the needle be destroyed Sidhe at the same time destroying its magnetism ; in other words, could the earth’s action on it be so precisely neutralized as to allow of its resting indifferently in all directions. The obvious mode of doing this, by the approach of a powerful magnet acting in opposition to the earth, proved much too coarse for our purpose, which, however, after a few trials, we found might be accomplished to any required degree of | apuiompte by the following simple contrivance, {two exactly equal. and similar magnets of equal strength be placed parallel to each other, but in a reverse position, and at such a distance, as. not. mutually to affect. each other’s magne- tism, and if in this situation they be firmly attached: to a piece _ of wood, glass, &c.,the system so formed will haye no polarity, i. eno tendency, to rest. in one rather than another situation, however suspended. This is clear; because whatever be the inclination, (4), of one of the magnets to: the line of dip, that of the: other will necessarily, be (180 + 4), and the directive forces, being represented, by the sines of these two angles, will always be equal and opposite, so that each magnet urges the system with equal force, but in opposite directions. The truth of this 188 Messrs. Babbage and Herschel on the [Sepr. proposition, it is no less evident, is independent of the axis of suspension, which may pass through a part of the system any how situated with respect to the magnets, in virtue of the property of a magnet whose force to turn a system, of which it makes a part, round a fixed centre, is the same whenever it is placed in the system, and the same as if it were in the centre. Hence it follows, that if two equal and similar magnets be laid parallel to each other, but ina reversed position, on a horizontal lass plate, freely suspended by a thread, ‘the system will be oon | of any polar tendency, (which we shall express by calling ‘such a system neutral.) It is difficult however to procure two magnets exactly equal, and ofequal force. But fortunately this is of no consequence, as a slight deviation from perfect neutrality may be corrected by inclining the stronger needle a little more or less to the plane of the plate. In fact the proposition is general; and by a proper adjustment of the positions of two magnets however unequal, with respect to the axis and to each other, they may be made to neutralize each other. As this adjustment however is nice, and as magnets influence each other, and our object moreover called for the utmost deli- cacy, we adopted a more refined application of the principle just detailed. A circular glass disc was prepared, eight inches in diameter, and suspended by three silk threads from a filament of silk, descending along the axis of a copper tube about five feet long, passing with stiff friction through collars in the cieling of the apartment, and serving nicely by means of an index to regu- late the height of the glass disc. At the opposite extremities of two diameters at right angles to each other, four equal small bar magnets were fixed in a vertical position, having alternately their north and south poles downwards. This position promised to present two material advantayves ; first, that in neutralizing the system we have not the whole polarity of the magnets to contend with, but only the small remains of directive tendency which arises from the magnetic axis in each not being precisely coincident with its axis of figure, since it is evident that an infinitely thin magnetic cylinder placed perpendicularly to the horizon, would from that cause alone be indifferent as to situation ; secondly, that in this situation their poles interfere with each other’s action on the plate revolving below them, less than in any other. Instead of our we might (and as will be seen occasionally did) place a — number of magnets round the circle, or within its area, ut for the experiments now in view four were enough. The system so constructed was found to require no after adjustment, being to all appearance perfectly neutral, so that this part of our purpose was sombitels accomplished, and the earth’s action eliminated from the inquiry. The irregular torsion 1826.] Magnetism of Metals, &c. arising from their Rotation. 189 of the silk-thread however still embarrassed us a good deal. ' But though this undoubtedly caused individual results to differ more from the mean than we had expected, it is not sufficient to account for a singular anomaly observed not only in the mean results of a great number of trials, but in all individual cases; viz. that by this mode of observation, zinc was invariably found to stand above copper in the scale of magnetic action, whereas in the determination by the statical method, where the deviation of the compass, was observed, the former metal was as invariably found to be placed below the latter, the other metals retaining their order. | Comparing the means obtained by the apparatus just described of all the lines in the table constructed of the results for copper, zinc, tin, lead, and of the six first for copper and antimony, the proportional intensity of magnetic action for each respectively will be MUG cnn bee ¥\chateeecsrepwoveup ey PUL CODD lees nesco tis trereess adeeute LUO einai ha ita isin uae «sp es Kea ena sae os VOL Beadacs. xs divi Uva eeere SUE. COVE . 0°25 ADAMODY se + chin ndee cen easie «aig eeree The smallness of the number for antimony is here also very remarkable. That for bismuth deduced by this means would be still more minute, so small indeed that the torsion of the thread would not allow of its magnitude being fairly determined, the suspended system merely performing extensive oscillations in very long times. | | his method however requires us to operate on very consider- able quantities of the substances under examination, a great disadvantage, as it cannot be applied to the scarcer metals, and does not admit of the use of the common ones in a state of rigo- rous purity. A method at once more simple and expeditious, and allowimg of our acting on small quantities of matter, is to suspend portions of the different bodies we would try, similar in form and exactly equal in size, over the revolving magnet, and noting either, dynamically the times of successive revolutions, or, statically the point of equilibrium between the rotatory force and the torsion of the string. This method we pursued in a very interesting part of the inquiry, viz. in investigating (after M. Arago) the effect of a solution of continuity, partial or total, in the mass acted on. | : A disc of lead of two inches in diameter and one-tenth thick, was suspended in a small thin wooden tray at a given distance from the horse-shoe magnet, revolving with the usual velocity, at first entire, and then successively cut with a chisel in radii nearly up to the centre, as represented in the following page. | 190 - Messrs: Babbage and Herschel on'the (Srv'r. Fig. 2. : 3. ait | cee Ba S/ 18 Fi The times observed and forces deduced in the several cases were as follows: . Fig. A. : alin oe Disc cut asin|Disc cut as in| Dise cut as in|Disc cut asin Disc cutasin — Rev.) Dike sac Fig. 1. |, Figu®., iL,.Fige S| Figo 4s i), Big, Be im fipmeh ex fy ey pal any gol ee] Tale Tp 1 | 28°2 | 1258 | 30-9 |1047} 33°1L | 913) 42-b | 564] 48-1 | 482) 55-6 | 324 . 2] 41-2 | 1V78 | 44-5 ATA 59-8 | 69:0 81-4 | 302 3 | 50°6 | 1172 | 55°0 59-0 TA-7 86°6 103°3 | 281 4 | 587 | 1161 | 63-9 68'3 88°0 102°1 124-5 | 258 5} 66°4 | 1134 | 72-0 772 100-0 116°8 145°9 | 235 Similar effects were observed in other metals, but in different degrees. For instance, in the case of soft tinned iron, the same number of cuts, made in the same manner, produced a very slight diminution of force, while in copper the effect of the same ration was to reduce the force in the ratio of 1 to 0:20. A thin disc of copper suspended at a given distance over the Nee 8 magnet, performed six revolutions from rest in 54*8. It was then cut in eight places in the direction of radii nearly up to the centre and 45° asunder, by which operation its magnetic , virtue was so weakened, that it now required 121*3 to execute the same number of revolutions. The cuts were now soldered up with tin, and the magnetic action was now found to be so far restored as to enable it to perform its six revolutions in 57*3, that is to say, very nearly in the same time as whenentire. This is the more remarkable, since tin, as we have seen, is not above half so energetic as copper when acting directly. This indirect 1826.] Magnetism of Metals; &c. arising from their Rotation. 191 mode of action, therefore, affords us a means of magnifying small magnetic susceptibilities, which may hereafter prove very valuable. To illustrate this more strongly, we suspended a brass disc of 2:25 inches in diameter, and 0°15 inch in thickness, as in the last case, and noted the time of its performing successive revo- lutions as follows : 4 | 1 rev. 2 rev. 3 rev. 4 rey. 5 rev. 20%2 29°1 35224); 40:8 45:7 It was now cut, as in the last case, but it being necessary for this purpose to use a saw, the abraded portions, which were pretty copious, were strewed over it with the intervention of a piece of thin paper, to obviate the effect of loss of weight, as nearly as might be. The times were now found increased as follows : _lrev. - 2 rev. 3rev. 4 rev. 5 rev. 41:1 ) 57°9 71:0 83:0° 93-7 being almost exactly doubled, and of course the force was. reduced in the ratio of about 4 to I. : The cuts were now cleanly soldered with bismuth; and though, as we have seen, the direct force of bismuth isso small as to be scarcely patcepale, yet its indirect effect in restoring — the magnetism of the brass was such as to cause the same arcs to be described in the following numbers of seconds : 1 rev. 2 rev. 3 rev. 4 rev. 5 rev. 232 8397 48-4 SOD Oat which require the exertion of an accelerating force more than double that developed in the last trial. | The bismuth was now melted out, and the cuts being carefully washed with melted tin, were filled with fresh tin, which was allowed to fix, and the disc being trimmed, and replaced, the times were now found to be 217 B08 BBO 43°5 48-7. The restoration of energy, as in the case of the copper disc, is here very manifest, the times of rotation being nearly reduced to their original magnitude. The comparison of these gives for the accelerating forces | PASE MTC Ls iv ae ade sp.b, bye.) 1:00 | Copper, uncut. ...... 1:00 0 Sipe REVAL NR 0:24 Ciba sym dae sh 0:20 soldered with bismuth 0°53 soldered with tin 0:91 soldered with tin.... 0°88 The effects of soldering with lead and with fusible metal 192 Mr. Brayley on the Rationale of the Formation [Sxpt. were also tried, and found to be both represented on the same scale by the same fraction, viz. 0°85, being but very little inferior to tin. } When the soldering is imperfect, the effect in restoring the magnetic action is proportionally weaker, but the influence of ever so small a free metallic communication is sensible. A disc of lead cut in 8 radii as above was found to make one revolution in 58°3. It was then wetted so as to fill the cuts with sulphuric acid, and the time of revolution was found to be 57°3; so that the influence of sulphuric acid, even when thus magnified, is still equivocal; and its magnetism, if it exists, can hardly be estimated at a thousandth part of that of copper, and as probably still lower. 7 he reduction of the metals to filings or to powder, was found to produce a still more striking diminution of their magnetic energy ; and a class of experiments of great interest, as to the effect of the agglutination of these powders by metallic and non- metallic cements and liquids, immediately presents itself; into which want of leisure only has hitherto prevented our entering, as well as on the important subject of the magnetism of metallic alloys and atomic combinations, with which this branch of the inquiry is essentially connected. | (To be continued.) | Articue III. On the Rationale of the Formation of the filamentous and Mamillary Varieties of Carbon; and on the probable Existence of: but two distinct States of Aggregation in Ponderable Matter. By E. W. Brayley, Jun. ALS. (To Richard Phillips, Esq. FRS. &c.) DEAR SIR, July 7, 1826. I HAVE perused with much attention and interest Dr. Colqu- houn’s paper.on the new capillary variety of carbon, &c. in the Annals for the present month; and I beg to offer a few remarks on some of the phenomena and substances in question, which you may, perhaps, deem worthy of insertion as cop en 1 to his communication. Dr. Colquhoun regards the mode of formation of the filamentous carbon he so minutely describes, as inexplicable by any facts which chemistry can as yet furnish ; and he considers the evidence afforded by the external charac- ters of that and some of the mammillated varieties, of their forms having been assumed out of a state of fusion, to be, when viewed in conjunction with the known infusibility of carbon, anomalous in the extreme. I may possibly have overlooked or 1826.] >» of the new: Varieties of Carbon, Sc. |, 193 underrated some fact in the case, which has a material bearing on the cause of the phenomena to be explained; but it does appear to me that these phenomena are susceptible of a ready and satisfactory explanation, for which Dr. C. himself has pro- vided the materials. For the purpose of showing this, a brief recapitulation of the principal facts related will be necessary. A current of an aéri- form combination’of carbon is. made to act on iron heated nearly to whiteness, and defended from the action of atmospheric. air. The gas undergoes decomposition, a portion of its carbon combines with the iron, producing steel, whilst another portion is precipitated in various forms, but in a state of purity. And the characters of some of the varieties of the carbon thus pro- duced, indicate them to have been in a state of fusion at the moment of their. formation.» But Dr. Colquhoun views the infu- sibility of carbon at the temperature to which the gas is subjected, as being at present an insuperable difficulty in the explanation of the phenomenon; as one which renders it impossible to understand the nature of the process. by which the carbon is deposited, either in the new method of making steel, or in the operation of obtaining gas from coal. | I may here observe, before proceeding to offer what I conceive to be the rationale of this process, that the statement made by Dr. C. that carbon has not exhibited even a tendency to fusion in the most intense artificial heats, is not exactly correct; for although it is unquestionably one of the most infusible of bodies, yet distinct evidence of the partial fusion both of graphite and of the diamond, were obtained by the late Dr. E. D. Clarke, in his experiments with the oxy-hydrogen blowpipe. But even if there ‘were no evidence of the fusion of carbon by artificial means, it is not obvious, I think, why that circumstance should militate against the belief, that a substance bearing every appearance of having once been liquid, should in reality have been in that state. All that could fairly be said, would be, that in experi- ments instituted for the purpose of endeavouring to fuse carbon, it remained infusible, at a temperature equal or even superior to that to which it could have ic subjected, by the process in question. And this would be merely one of the many cases in the arts dependent on chemical principles, in which certain phenomena take place, naturally, as it were, in certain opera- _ tions, that cannot be produced by experiments expressly directed. to those objects; and which, in fact, are as inexplicable, and as difficult of access, as many of the operations in which the powers of nature are alone concerned. | And now, merely remarking that my reason for regarding the fusion of graphite as part. of the.evidence of that of carbon having been effdoted , will appear in a subsequent communication, I proceed to submit, with much deference, the rationale of the New: Series, vow. x11, Q } 194 Mr. Brayley on the Rationale of the Formation [Suvri formation of the varieties of carbon in question, which the con- sideration of the facts has suggested to me; and which, by recon~ ciling them to each other, removes the supposed anomaly,» . - It issimply this: That the carbon, existingin the carburetted hydrogen in the gaseous state, retains that state uponitsseparation — from the hydrogen, and thence, as we know that gaseous carbon must require a temperature of unknown intensity for its preser- vation in that form, passes into the liquid state... This, however, in consequence of the high temperature required for its liquefac- tion, a temperature far exceeding that of the ‘steel-chest or the gas-retort, it cannot retain, (a circumstance which is in perfect agreement with the great infusibility of carbon as evinced. by otpeeeens 3) and it passes, instantaneously, into a state of solidity ; its liquefaction, of course, taking place, ‘ only in the moment of mamillary or filamentous formation.” :The result of this operation would certainly be, the production of substances with characters indicating their forms to have been ‘‘ assumed out of a state of fusion.” And yet the fact of/the great infusi- bility of carbon, instead of being edntradicted by the apparent phenomena, would be in reality a chief cause of the appearances exhibited by the substances, The instantaneous passage from the liquid to the solid state, would prevent: the agency of the surrounding gaseous substances, of the iron, or of the earthen vessel, from interfering with the cohesive aflinity and tendency to union of the particles or molecules of solid carbon resulting from the transition, and they would of course unite in the freest manner, and, according only to their own inherent. properties, independently of the action of the contiguous bodies. And the characters of the forms of carbon so produced, appear indeed to indicate that this was actually the case. One of them consists of fine capillary filaments. Now all we know, I believe, of cor- puscular forces, and of their agency in the production of solids, would lead us to believe, that the sudden production and fixation of the solid particles of carbon, supposed in the explanation I have ventured to give, would cause an aggregation of them in one direction only, which would of course. produce a collection of filaments; the suddenness of the operation preventing the attraction of crystallization from having place. That attraction would scarcely have time for incipient agency, before the carbon would have ceased to be amenable to its influence. Nor does the mamillary form of the other variety in any way oppose this hypothesis: all the other mamillary concretions in nature with which we are acquainted, (and on examination of the carbon it will doubtless be found to be the case with that,) arise from the aggregation of fibres radiating from a-centre in every direction, and tending thus to form spheres, the complete formation of which, however, is interrupted and prevented, by the fibres proceeding from different centres meeting and intercepting each _ other in the operation, by which the spheres become irregularly’ | 18262] «oh af the new Varietiés of Carbon, 8. 195 compressed, modified, and intermingled. That such is the structure of mamillary concretions, the examination ofa specimen of: botryoidal ‘iron-stone, or of malachite, will convince every observer. And the tendency to unite around centres, which all bodies manifest, when at liberty to exert their inherent qualities, unaffected by surrounding or contiguous substances, would produce this mamilldary structure, as in the instances just meti- tioned, from the filaments already formed by the attraction before described. | Ph ‘I cannot but think it probable, that if this carbon could be kept in fusion, and be slowly instead of rapidly cooled, the atoms would arrange themselves in several directions at oncé, or in a crystalline arrangement, and that thus the diamond would be ‘the result. e know crystallization to be in all cases a gradual process, and ‘to arise from ‘liquidity continued for a sensible’ portion’ of time. On-the other hand, the instantaneous transition from the liquid to the solid state appears to be the cause of the pulverulent or irregular form of the varieties of carbon, obtained by passing alcohol and cer- tain oils ‘through ignited porcelain tubes. And it may be remarked, that the carbon produced by the decomposition of the gas, in Mr. Macintosh’s process for making steel, must necessarily be in a state to exert its inherent properties, much more freely and independently, than in the cases last referred to; and hence’ the greater approximation of the carbon, sepa+ rated in that process, to what we may suppose to be, pre- eminently, the. proper form of that substance. As so many other substances, when in their nascent state, exhibit their properties in a much more decided manner than at other times, this may also be one of the reasons why this carbon is in a denser state of aggregation, &c. than in its more common forms, obtained under circumstances less favourable to the free deve- lopment of its inherent properties. ae 2 ! ) ~~ But it may, perhaps, be objected to the hypothesis I have advanced on the formation of the mamillary and filamentous varieties of carbon, that we have no proof that the liquid state necessarily intervenes between the aériform and the solid States, and that, for aught we know, a body may pass di- rectly from the former to the latter. It appears to me, how- ever, that the great bulk of facts in Chemistry, in which the passage of bodies from one state to another is concerned, together with all that we know of the production of vapours from liquids, and the condensation of vapours into liquids reci+ procally, points to the conclusion, that the liquid is a necessary and an invariable intermediate state to the solid and the gaseous. I shall not, however, content myself with this general statement. I shall first urge some reasons for thinking that the above is the case in all instances, derived = some recent discoveries in i * | 196 Mr. Brayley on the Rationale of the Formation [Supr. chemistry; and then proceed to adduce experimental evidence that it actually occurs in some cases, distinguished from others only by the circumstance of their taking place at temperatures sufficiently low, to allow of their being made subjects of experi- mental observation, tho It will be sufficient merely to state that Mr. Faraday’s experi- ments on the liquefaction of gases,* have annihilated the distinction formerly believed to exist between gases and vapours, and have shown them to differ merely in density, and conse- quently that the passage from the rarest gas to the densest. vapour is by indefinable and continuous degrees. In like manner, the experiments of M. Cagniard de la Tour on the combined action of heat and pressure on certain liquids,} toge- ther with some now well-known facts indicated by the phieno- mena attending the production of steam from the generator of Mr. Perkins’s steam-engine, show, I think, that no line of demarcation can be drawn between vapours and liquids, but that they likewise pass into each other in a perfectly continuous manner, by imperceptible degrees. , It appears to me, in short, that the aggregate of our knowledge respecting the different forms of ponderable matter, as regards their relations to latent heat, according to the received doctrine on the cause of fluidity, leads directly to the conclusion, that there are only two such forms, the so/id and the fluid; the distinction of the latter into aériform and liquid being still however retainable with propriety as a matter of convenience, though there seems every reason to believe it a distinction that has no real existence. The accurate reasoning of Mr, Graham, I may also remark, in his observations on the absorption of gases by liquids, quoted in the same number of the Anna/s in which Dr. Colquhoun’s paper appears, as well as the experimental evidence he cites, is entirely favourable to this view of solidity and fluidity being the only distinct physical forms, or states of aggregation, of ponderable matter; the gaseous and the liquid states being merely continuous degrees of one and the same form.} * See Phil. Trans, for 1823; or Annals, N.S. vol. vii. p. 89. > _ + Ann. de Chim, et de Phys. tom, xxi.; or Annals, N.S. vol. vs p. 290, t Since the above paragraph was written, I have read a paper by Professor Oersted, published in Schweigger’s Journal for December last, in which‘are detailed the results of a series of experiments made by him and Capt. Schwéndsen, with the view of deter. mining whether the law of the compression of aériform bodies discovered by Mariotte extended to high pressures, which had been doubted by certain mathematicians. The result was the complete verification of Mariotte’s law for all pressures, whilst the gases retain their aériform state. At the conclusion of the paper, Prof. Oersted expresses his opinion, derived from experiment, that /iquids are subject to the same law; and if this shall, on further investigation, pore to be the fact, it will tend to confirm my opinion, | given above, that the gaseous and the liquid states‘are essentially the same. : The following is a translation of the passage :—‘* The compression of liquid bodies reducible to drops, is, as far as our experience yet goes, subject to the same law; here, too, the compression and the compressing power seem to bear a direct relative prop tion. We may, therefore, assume, that the gases, converted into liquids reducible to drops, begin again to follow. the same law to which they answered as gases. If this should be confirmed by further experiments, it may be said that the compression of 1826.}) © wf the new Varieties of Carbon, 8c. AMF «This being premised, the next step in the inquiry is to ascer- tain what are the’ means, exclusive of crystallization, of reducing a rarer to a denser form of matter. But two modes of doing this are at present known; viz. diminution of temperature ; and the approximation ‘of the molecules of bodies by mechanical means, in which an evolution of caloric takes place, The pro- duction of solid from aériform matter by the combination of two gaseous bodies, is not to be regarded as a third method of effecting this; for it is merely a case of the first mode just mentioned ; ihe temperature at which the elements of the solid which is formed are retained in the gaseous state, being insuffi- cient tovallow their combination to remain aériform. The pro- duction of solid carbonate of ammonia by the union of the ‘carbonic acid and ammoniacal gases, is a familiar illustration of this process. Now, as already observed, there is every reason to believe, _ that no definite distinction exists between the state of gas and liquid, but that the only physical difference between the lightest gas and: the heaviest liquid, is in density; the intermediate degrees being supplied by vapours and liquids increasing in density in the most gradual manner. .We know too that the first result of the i Hg pa of cold to a gas susceptible of reduction to the liquid state, is its condensation ; we know that this condensation goes on with the diminution of temperature, until at length, when the process has been carried to a sufficient extent, the result is the successive production of dense vapour and of liquid. Itaffords no argument against what I am advanc- ing, that the combined application of cold and pressure is in many cases necessaty to effect this; for each successive stage in the - condensation is produced, with the one agent, by the abstraction of caloric, and attended, with the other, by its evolution ; so that the passage of latent into sensible heat takes place in the same manner, and is as materially concerned in the process, as would be the case, were either method to be employed exclu- sively. With this train of consistent phenomena before us, and with bodies ceases to conform to these rules, only in the moment of their transition from one state of aggregation to another.” . The reader, however, will not fail to perceive, that a circumstance alluded to in the last ¢lause, is unfavourable to my opinion ; and as the statement is one of some import- ance, and Iam not quite satisfied of the accuracy of the foregoing translation, it may beas well to subjoin the extract in the original German. ** Die Compression tropfbar fliissiger Korper ist, so weit bis jetzt unsere Erfahrungen reichen, demselben Gesetze unterworfen; auch hier scheint Compression ‘und Druck- kraft im Verhiltniss zu stehen. Man kann daher annehmen, dass ‘die zu tropfbaren * Flissigkeiten umgewandelten Gase von Neuem anfangen dem niimlichen Gesetze zu ~ folgen, welchem sie als Gase entsprachen. ‘Auch ist es ziemlich wahrscheinlich, dass die in feste Kérper umgewandelten Fliissigkeiten jenem Gesetze unterworfen sind. ‘Wenn sich diess durch weitere Versuche bestatigt, so kann man sagen, dass die Zusam- menpressung eines Korpers nur allein in den Uebergangsmomenten aus einen Aggrega- tions-Zustand in den andern aufhére sich nach jenem Gesetze zu regeln,” 198 Mr. Brayley on the Rationale of the £ormation [Sxvvi the general fact, in addition, that in all, cases completely within our sphere of observation, the solid results from the Aiquid state; may we not fairly infer, that the liquid state invariably takes place between the aériform and the solid ?—that itis a necessary and anerinane step in the production of solid from gaseous matter : isuiwon? .2asomns I now proceed to adduce some experimental evidence on ‘this point. In the sublimation of bodies which do not require a very elevated temperature for their volatilization, and which are, therefore, fully open to observation during the process, such as benzoic acid, some of the salts of ammonia, and sulphur, we may observe fhe following facts, Ifthe temperature of the-vessel or portion of the vessel into which the vapour rises, is insufficient to retain the substance, for a sensible interval, in the liquid state, the result is an indistinctly fibrous or a compact mass, bearing; however, marks of fusion. But if the heat is sufficient to allow the condensed vapour to remain liquid a sensible portion of time, more or less perfect, though usually minute crystallization is the result. The former of these cases appears to me to be precisely similar to that of the production of Sediigebaddentitigal the mamillary carbon. Andas an instance in nature of a corre- sponding kind, I may refer to the various forms of volcanic sulphur, when viewed in connexion with the chemical and geo- Logical circumstances under which they are produced. > he evidence which I have given, tending to show that the liquid state always intervenes between the solid and the aériform, also induces me to believe, that in the transfer of cars bon from the negative to the positive pole of the Deflagrator, observed by Dr. Hare,* the carbon is first liquefied, and then evaporated, being driven in vapour to the opposite pole: by the galvanic current. This is the converse of the deposition of carbon bearing marks of fasion: in that case the temperature is insufficient to preserve the carbon in a liquid form; in this, it is too high to allow that form to be retained, the substance imme- diately acquiring elastic fluidity. It may be useful to add a few words in explanation of the various forms assumed by the deposited carbon. Ihave already suggested an idea on the origin of the capillary form; and [ may here remark, in continuation, that though for various reasons already stated, we must not regard crystallization as having been, in any material degree, concerned in its produc tion, yet a species of polarity, as Dr. Colquhoun has already observed, has undoubtedly had an influence in its formation ; and it appears to me, that the tendency to a rectilinear direction, which so many of the most refined investigations of modern science haye shown both ponderable and imponderable matter to possess, or the tendency to polarization, is prior, in its agency — : * See Annals, N, Ss vol. ive Ps 121, ’ 1826.) .nief the new. Varieties, of Carbon, wed «hf 199° in. pondefable: substances, even to the crystalline attraction: itself ; and, that itis in fact the first cause of solidity.. Thus the solidification of water commences with the production of fibres, or needles; which, by their lateral aggregation and intersection at certain angles, at length produce the solid congeries of crys-. tals we term ice.’ This view does not oppose the sagacious inference of Dr. Young, that a more or less perfect crystalliza- tion is the universal,cause of solidity ;* for the tendency I have mentioned would of itself produce an aggregation of matter of one dimension only, viz. that of length ; whereas the tendency to aggregation in several directions,orcrystalline attraction, produces the other dimensions of solidity, breadth and thickness.+ In the: case of the fibres of carbon, crystallization has been exerted toa, sufficient.extent to give them sensible thickness. Their collec-. tion into docks: would of course result from the mutual lateral attraction ofthe fibres, when formed. There are many instances inthe mineral kingdom, of two substances belonging to the same mineral-species, or, in other words, to the same material substance, which are very nearly as different from each other, as are these: fibres of carbon from the diamond. For example: who, at first sight, would imagine, that the silky, white, hight, perfectly flexible, and nearly opaque fibres of amianthus, were identical in their specific: nature with the green, transparent, prismatic, rigid, and comparatively hard and heavy crystals of actynolite ? yet.such is the. fact; and some mineralogists have accordingly classed them in their systems as varieties of the same mineral.{ In this case, the polar attraction appears chiefly to have had place in the production of the amianthus, as m that:of the carbou ; whilst the actynolite has resulted from the unchecked influence of crystalline attraction. i, . That the slaty carbon of the gas-retorts should be the result. of a gradual and continued process, Dr. Colquhoun appears to consider the most unaccountable part of the phenomena he has so well detailed. If, however, the solution | have suggested of the principal problem is correct, this gradual accumulation: of carbon may be explained in the following manner. Dr. C. states, that the stratified portions of this carbon are quite com- pact in the small. Now is it not reasonable to infer, that. each separate stratum is the result of one process of rapid solidifica- - - * See his Lectures on Natural Philosophy, vol. i.p. 627. ' + Some evidence; I think, that this tendency to linear arrangement, or to polarization, is the first power operating on solid particles of matter towards their aggregation, is afforded by the facts pointed out by Sir E. Home and Mr. Bauer, that the most minute fibres in nature with which we are yet acquainted, those constituting the muscles and nerves of animals, consist each of a simple row of attached globules ; and that the com- mencement of the operation by which coagulated blood becomes vascular, is the attach- ment together in one direction of its constituent globules, forming such fibres. : “4 See, ann Prof. Mohs’s Treatise on Mineralogy, translated by Haidinger, VOL. ls Po ° st 2 2 : ; + a 200- Mr. Brayley on the new Varieties of Carbon. [Suvr. tion, from the liquid to which the gaseous carbon is reduced; so. that the successive depositions, arising from the repeated: pro-. ductions of carbon, form the stratified mass? ‘ Lintended to have concluded this paper with a few remarks, suggested by Dr. Colquhoun’s details, on some other forms of: carbon, existing in nature, as well as resulting from the processes of art; and on the prevalence of ‘that body throughout nature, and its presence, as well as that of sulphur, in every stage of the formation of the crust of the earth, from that in which the primary rocks were produced, down to the era of the newest tertiary beds. But I have extended the foregoing observations to so great a length, that I must reserve these for a future’ opportunity. It would, however, be uncandid, as well as unphi-: losophical, were I to conclude, at present, without noticing a fact, that appears to militate, in some degree, against the hypothesis I have advanced, that the liquid state is necessarily intermediate between the solid and the aériform ; and which I must acknow- ledge I donot as yet understand. This is the evaporation of ice: and. snow, without any previous visible liquefaction, at tempera-~ tures that would immediately condense aqueous vapour from any: other. source,.into snow itself. The most: satisfactory experi- ments on this subject, that I am aware of, are those recorded by Mr. Luke Howard. In one of them, 2600 grains of hard snow. lost 27 grains by evaporation in ten hours, the temperature varying only between 12° and 28°.* Perhaps, however, the fact may admit of this explanation. The tendency to assume: the vaporous state, which is sufficiently strong to. overcome the cohesive attraction of the solid ice, at such low temperatures, may also be sufficient, to cause the instantaneous passage of the water, its first operation on the ice must be supposed to produce, into aqueous vapour. At all events, the existence of the vapour of water at a temperature so far below that required for its soli- dification, with the additional condensing power of radiation from the surface of the snow, is as apparently anomalous, as the instantaneous production and evaporation of water, presumed in my view of the case, can be imagined to be. Before | terminate this communication, I would also notice the production of a solid ingot of copper from the solution of a salt of that metal, which Dr. Colquhoun alludes to as being so anomalous. It is possible, that, in this case, as well as in that of the formation of the capillary carbon, | may have overlooked the difficulty. But 1 am unable to perceive any thing in the process, that cannot be readil scaled: The oxide in the solution of a cupreous salt is diffused throughout the solution, of which every drop contains a portion. Now when this oxide is reduced, by its oxygen passing to the plate of iron immersed * Climate of London, vol. i, notes to Tab. xc. 1826.) Mr. Faraday on Sulpho-ndphthalic Acid. . 201 in ‘the solution, an indefinite number of particles of metallic copper are produced in the fluid, at insensible distances from each other, and there is nothing that can interfere with the powerful cohesive attraction they must have for each other, especially in this nascent state : they are under the most favour- able’ circumstances for aggregating into a mass of metal, and such a mass they accordingly form. It seems, indeed, difficult to conceive; that any other should be the result. | ‘The ‘consideration of these subjects has led me, perhaps, into details somewhat irrelevant; and it may be thought that there are too many postulata to be granted, before what L have advanced on the origin of the new varieties of carbon can be received: this may probably be the case; but 1 deemedoit | most ingenuous to state my views on the subject, in the order in which they were presented to my own thoughts ; and I may be permitted to hope, that the simplicity of the explanation that has occurred to me, and the facts I have adduced in support of it, and of the inductions on which it is founded, will meet with some attention. It may also be observed, that the essential identity of the liquid and aeriform states, is not’a necessary part of the explanation I have given of the manner in which the filamentous carbon is produced ; nor of the grounds for believing, that the liquid always intervenes between the gaseous and the solid states. | : nal aige Should what I have offered prove in any degree useful to the chemist to whom we are indebted for the discovery and account of the substances in question, in any further researches on them he may be disposed to undertake, I shall-consider that Thave not made these observations in vain. And as they have insensibly assumed a somewhat critical tone, I beg to dis- avow any intention of animadverting on Dr. Colquhoun’s useful paper with that view ; my aim having been, solely, to endeavour to develope the causes of the phenomena he describes. I am, Dear Sir, avenue very truly, _ E,W. Braycey, Jun. ArticLe IV. On the Mutual: Action of Sulphuric Acid and Naphthaline, and on a new Acid produced. By M. Faraday, FRS. Cor- _ responding Member of the Royal Academy of Sciences, &c.* In a paper on New Compounds of Carbon and Hydrogen, lately honoured by the Royal Society with a place in the Philo- sophical Transactions, I had occasion briefly to notice the pecu- * From the Philosophical Transactions for 1826, Part JI. 202 Mr. Faraday on the Mutual Action of Sulphurie Acid [Save liar action exerted on certain of those compounds by sulphurie acid. During my attempts to ascertain more minutely the general nature of this action, I was led to suspect the occasionab combination of the hydro-carbonaceous matter with) the acid, and even its entrance into the constitution of the salts, which the acid afterwards formed with bases, Although this opinion: proved incorrect, relative to the peculiar hydro-carbons forming: the subject of that paper, yet it led to experiments upon analo~ gous bodies, and amongst others, upon naphthaline, which termi- nated in the production of the new acid body and salts now to be described. | 49 on orpiss Some of the results obtained by the use of the oil-gas-products are very peculiar. If, when completed, I find them sufficiently interesting, I shall think it my duty to place them before the: Royal Society, as explicatory of that action of sulphuric acid which was briefly noticed in my last paper. [ of 63 Most authors who have had occasion to describe naphthaline, — have noticed its habitudes with sulphuric acid.. Mr. Brande, several years since,* stated that naphthaline dissolved in heated sulphuric acid “in considerable abundance, forming a deep violet-coloured solution, which bears diluting with water without decomposition. The alkalies produce in this solution a white flaky precipitate, and if diluted the mixture becomes ome opalescent, in consequence of the separation of numerous small flakes.” The precipitate by alkali was probably one of the salts to be hereafter described. 1 mony oF a ; Dr. Kidd observes,+ that “it blackens sulphuric acid when boiled with it; the addition of water to the mixture having no: other effect than to dilute the colour, neither does any precipi- tation take place upon saturating the acid with ammonia.” >” Mr. Chamberlain states, that et acid probably decom-: poses naphthaline, for that it holds but.a very small quantity im solution. The true interpretation of these facts and statements, will be readily deduced from the following experimental details. 1. Production and Properties of the new Acid formed from Sul- phuric Acid and Naphthaline, . Naphthaline, which had been almost. entirely freed from naphtha by repeated sublimation and pressure, was pulverized ; about one part with three or four parts by weight of cold sulphuric acid were put into a bottle, well shaken, and left for 36 hours. The mixture then contained a tenacious deep-red fluid, and a crystalline solid ; it had no odour of sulphurous acid. Water being added, all the liquid and part of the solid was dissolved ; a few fragments of naphthaline were left, but the * Quarterly Journal of Science, viii. p. 289, 1819. + Philosophical Transactions, 1821, p.216. . t Annals of Philosophy, N.S. vi. p. 136, 1823, 1826.) and Naphthaline, and ona neiw Acid produced... 268 greater part was retaiied in solution. The diluted fluid being filtered was of alight-brown tint, transparent, and of an acid and bitter taste. : sq ei batisis od: vidisiss . For the purpose of combining as much naphthaline as possible with the sulphuric acid, 700 grains, with 520 grains of oil of yitriol, were warmed in a Florence flask until entirely fluid, and were well shaken for about 30 minutes. The mixture was red; and the flask being covered up and left to cool, was found, after some hours, to containy at the bottom, a little brownish fluid, strongly acid, the rest of the contents having solidified into a highly crystalline mass. The cake was removed, and its lower surface having been cleaned, it was: into another Florence flask with 300 grains more of naphthaline, the whole melted and well shaken together, by which a uniform mixture was obtained ; but opaque and dingy in colour. \ It was now poured into glass tubes, in which it could be retained and examined without con- tact of air. In these the substance was observed to divide into two portions, which could easily be distinguished from each other, whilst both were retained in the fluid state. The heavier portion was in the largest quantity; it was of a deep-red colour, opaque .in tubes half an ineh in diameter, but in ‘small tubes could be seen through by a candle, or sun-light, and appeared perfectly clear. ‘The upper portion was also of'a deep- red colour, but clear, and far more transparent than the lower : the line of separation. very defined. On cooling the tubes, ‘the lighter substance first solidified, and after some time the heavier substance also became solid. In this state, whilst in the tube, they could with great difficulty be distinguished from each others): : ere These two substances were separated, and being put into tubes, were further purified by being left in a state of repose at temperatures above their fusing points, so as to allow of separa- tion ; and when cold, the lower part of the lighter substance, and the upper, as well as the lower part of the heavier substance, were set aside for further purification. The heavier substance was a red crystalline solid, soft to the nail like a mixture of wax and oil. Its specific gravity. was from 19 to 1:4, varying in different specimens ; its taste, sour, bitter, and somewhat metallic. When heated in a tube, it fused, forming as before a clear but deep-red fluid. Further heat decomposed it, naphthaline, sulphurous acid, charcoal, &c. being produced. When heated in the air it burnt with much flame. Exposed to air it attracted moisture rapidly, became brown and damp upon the surface, and developed a coat of naphthaline. It dissolved entirely in alcohol, forming a brown solution, Whenrubbed in watera portion of naphthaline sepa- tated, amounting to 27 per cent. and a brown acid solution was 204 Mr. Farailay on the Mutual Action of Sulphuric Acid (Str. obtained. This was found by experiments to contain a peculiar acid mixed with a little free sulphuric acid, and it may conve niently be called the impure acid. | toa The lighter substance was much harder than the former, and more distinctly crystalline. It was of a dull-red colour, easily broken down in a mortar, the powder being nearly white, and adhesive like naphthaline. It was highly sapid, being acid, bitter, and astringent. When heated in a tube it melted, form- ing a clear red fluid, from which, by a continued heat, much colourless naphthaline sublimed, and a black acid substance was left, which at a high temperature gave sulphurous acid and charcoal. When heated in the air it took fire and burnt like naphthaline. Being rubbed in a mortar with water, a very large portion of it proved to be insoluble ; this was naphthaline; and on filtration the solution contained the peculiar acid found to exist in the heavier substance, contaminated with very little sulphuric acid. More minute examination proved that this lighter substance, in its fluid state, was a solution of asmall quan- tity of the dry peculiar acid in naphthaline ; and that the heavier substance was an union of the peculiar acid in large quantity with water, free sulphuric acid, and naphthaline. It was easy by diminishing the proportion of naphthaline to make the whole of it soluble, so that when water was added to the first result of the experiment, nothing separated ; and the solution was found to contain sulphuric acid with the peculiar acid, But reversing the proportions, no excess of naphthaline was competent, at least in several hours, to cause the entire disappearance of the sulphuric acid. When the experiment was carefully made with pure naphthaline, and either at common, or slightly elevated temperatures, no sulphurous acid appeared to be formed, and the action seemed to consist in a simple union of the concentrated acid and the hydro-carbon. Hence it appears, that when concentrated sulphuric acid and naphthaline are brought into contact at common, or moderately elevated temperatures, a peculiar compound of sulphuric acid with the elements of the naphthaline is produced, which possesses acid properties; and as this exists in large quantity in the heavier of the bodies above described, that product may conve- niently be called the zmpure solid acid, The experiments mae with it, and the mode of obtaining the pure acid from it, are now to be described. _ Upon applying heat and agitation to a mixture of one volume of water, and five volumes of impure solid acid, the water was taken up to the exclusion of nearly the whole of the free naph- thaline present: the latter separating in a colourless state from the red hydrated acid beneath it. .As the temperature of the acid diminished, crystallization in tufts commenced here and 1826.] and Naphthaline, and ona new Acid produced... 205 there, and ultimately the whole became a brownish-yellow solid. A sufficient addition of water dissolved nearly the whole of this hydrated acid, a few flakes only of napthaline separating. » . A portion of the impure acid in solution was evaporated at a moderate temperature ; when concentrated, it gradually assumed a light-brown tint. In this state it became solid on cooling, of - therhardness of cheese, and was very deliquescent. By further heat it melted, then fumed, charred, &c. and gave evidence of the abundant presence of carbonaceous matter. | Some of the impure acid in solution was neutralized by potash, during which no naphthaline or other substance separated. The solution being concentrated until ready to yield a film on its surface, was set aside whilst hot to crystallize : after some hours the solution was filled with minute silky crystals, in «tufts, which gave the whole, when stirred, not the appearance of mixed solid salt and liquid, but that of a very strong solution of ‘soap.’ The agitation also caused the sudden solidification of so much more salt, that the whole became solid, and felt like a piece of soft soap. The salt, when dried, had no resemblance to sulphate of potash. When heated in the air, it burnt. with a dense flame, leaving common sulphate of potash, mixed. with some sulphuret of potassium, resulting from the action of the carbon, &c. upon the salt. : | Some of the dry salt was digested in alcohol to. separate com- mon sulphate of potash. The solution being filtered and evapo- rated, gave a white salt soluble in water and alcohol, crystalline, neutral, burning in the air with much flame, and leaving sulphate of potash. It was not precipitated by nitrate of lead, muriate of see or nitrate of silver. | It was now evident that. an acid had been formed peculiar in its nature and composition, and producing with bases peculiar salts. In consequence of the solubility of its barytic salt, the following process for the preparation of the pure acid was adopted. | | .. A specimen of native carbonate of baryta was selected, and its puvity ascertained. It was then pulverized, and rubbed in successive portions with a quantity of the impure acid in solu- tion, until the latter was perfectly neutralized, during which the slight colour of the acid was entirely removed. ‘The solution was found to contain the peculiar barytic salt. Water added to the solid matter dissolved out, more of the salt ; and ultimately only, carbonate and sulphate of baryta, mixed with a little of another barytic salt, remained. The latter salt, being much less soluble in water than the former, was not removed so readily by lixiviation, and was generally found to be almost entirely taken up by the last portions of water applied with heat. The barytic salt in solution. was now very carefully decom- posed, by successive additions of sulphuric acid,. until all the 206 Mr. Faraday on the Mutual Action of Sulphuric Acid [Seer ta was separated, no excess of sulphuric acid being” pet+ mitted. Being filtered, a pure aqueous solution of the peculiar acid was obtained. It powerfully reddened litmus paper, and had a bitter acid taste. Being evaporated to a certain degtee, a portion of it was subjected to the continued action of heat: hen very concentrated, it began to assume a brown colour, andy on cooling, became thick, and ultimately solid, and was ver deliquescent. By renewed. heat it melted, then began to fu charred, but did not flame ; and ultimately gave sulphuric and sulphurous acid vapours, and left charcoal. dst Sina Radthen portion of the unchanged strong acid solution was laced over sulphuric acid in an exhausted receiver. In some endl it had by concentration become a soft white solid, rently dry; and after a longer period was hard and brittle, In this state it was deliquescent in the air, but in close vessels underwent no change in several months. Its taste was bitter, acid, and accompanied by an after metallic flavour, like that of cupreous salts. When heated in a tube at temperatures below 212°, it melted without any other change, and on being allowed to cool, crystallized from centres, the whole ultimately becomin solid. When more highly heated, water at first passed off, andl the acid assumed a slight red tint; but no sulphurous acid ‘was as yet | sok nor any charring uilhtoahich ; and a portion being dissolved and tested by muriate of baryta, gave but a very minute trace of free sulphunc acid. In this state it was proba+ bly anhydrous. Further heat caused a little naphthaline to rise, the red colour became deep-brown, and then a sudden action commenced at the bottom of the tube, which spread over the whole, and the acid became black and opaque. ntinuing the heat, naphthaline, sulphurous acid, and charcoal, were evolved ; but even after some time the residuum, examined by water an carbonate of baryta, was found to contain a portion of the pecus liar acid undecomposed, unless the temperature had been raised to redness. OD These facts establish the peculiarity of this acid, and distin- guish it from all others. In its solid state it is generally a hydrate containing much combustible matter. It is ily soluble in water and alcohol, and its solution forms neutral salts with bases, all of which are soluble in water, most of them in alcohol, and all combustible, leaving sulphates or sulphurets according to circumstances. It dissolves in naphthaline, oil of turpentine, and olive oil, in greater or smaller quantities, accord+ ingly as it contains less or more water. As a hydrate, when it is almost insoluble in naphthaline, it resembles the heavier sub= | stance obtained as before described, by the action of sulphuric acid on naphthaline, and which is the solid hydrated acid, con taining a little naphthaline, and some free sulphuric acid ; whilst the Aghter substance is a solution of the dry acid in naphthaline; \ 1826.] and Naphthaline,andonanew Acid produced: °° 20% the water present in the oil of vitriol originally used, being suffi- cient to cause a separation of a part, but not of the whole, 2. Salts formed by the peculiar Acid with Bases. These compounds may be formed, either by acting on the bases or their carbonates by the pure acid, obtained as already described; or the impure acid in solution may be used, the salts resulting being afterwards freed from sulphates, by solution in alcohol. It is; however, proper to mention, that another acid, composed of the same elements, is at the same time formed with the acid in question, in small, but variable proportions. The impure acid used, therefore, should be examined as to the presence of this body, in the way to be directed when speaking of the barytic salts; and such specimens as contain very little or none of it should be selected. ; | Potash forms with the acid a neutral salt, soluble in water and alcohol, forming colourless solutions. These yield either transparent’ or white pearly crystals, which are soft, slightly fragile, feel slippery between the fingers, do not alter by expo- sure. to air, and are bitter and saline to the taste." They are not very soluble.in water; but they undergo no change by repeated solutions and crystallizations, or by long-continued ebullition. The solutions frequently yield the salt in acicular tufts, and they often vegetate, as it were, by spontaneous evaporation, the salt creeping over the sides of the vessel, and running to a great distance in very beautiful forms. The solid salt heated in atube gave off a little water, then some naphthaline; after that a little catbonic and sulphurous acid gases arose, and a black ash remained, containing carbon, sulphate of potash, and sulphuret of potassium. When the salt was heated on platinum foil, in the air, it burnt with a dense flame, leaving a slightly alkaline sul-- phate of potash. — {ai ve ) MEV Soda yields a salt, in most. properties resembling that of Larose ;. crystalline, white, pearly, and unaltered in the air. I thought that, im it, the metallic taste which frequently occurred with this acid and its compounds was. very decided. The action of heat was the same as before. Ammonia formed a neutral salt imperfectly crystalline, not deliquescent, but drying in the atmosphere. Its taste’ was saline and cooling. It was readily soluble in water and alcohol When heated ‘on platinum foil it fused, blackened, burnt with flame, and left a carbonaceous acid-sulphate of ammonia, which by further heat was entirely dissipated. Its general habits were those of ammoniacal salts. When its solutions, though pre- viously rendered alkaline, were evaporated to dryness at common temperatures, and exposed to air, the salt became strongly acid to litmus paper.” This, however, is a property common to°all soluble ammoniacal.salts, I believe, without exception. | 208 Mr. Faraday onthe Mutual Action of Sulphuric Acid [Serr. - Baryta, It is easy by rubbing carbonate of baryta with solu- tion of the impure acid, to obtain a perfectly neutral solution, in which the salt of baryta, containing the acid already described, is very nearly pure. There is in all cases an undissolved por- tion, which, being washed repeatedly in small quantities of hot water, yields to the first portions a salt, the same as that in the solution. As the washings proceed, it is found, that the salt obtained does not burn with so much flame on platinum foil, as that at first separated ; and the fifth or sixth washing will per- haps separate only a little of a salt, which, when heated in the air, in small quantities, burns without flame in the manner of tinder. Hence it is evident that there are two compounds of baryta, which as they are both soluble in water, both neutral, and both combustible, leaving pr Pie of baryta, differ probably only in the quantity of combustible matter present, or its mode of combination in the acid. | It is this circumstance, of the formation of a second salt in small but variable quantities with the first, which must be arded against, as before-mentioned, in the preparation of salts han the impure acid. It varies in quantity according to the proportions of materials, and the heat employed ; and I have thought, that when the naphthaline has been in large quantity, and the temperature low, the smallest quantity is produced. When the impure acid is used for the preparation of the salts now under description, a small portion of it should be examined by carbonate of baryta, as above, and rejected, if it furnish an important quantity of the flameless salt. . hese bodies may be distinguished from each other provi- sionally, as the' flaming and the glowing salts of baryta, from their appearances when heated in the air. The latter is more distinctly crystalline than the former, and much. less soluble, which enabled me, by careful and repeated crystallizations, to obtain both in their pure states. | BAHL) The flaming salt, (that corresponding to the acid now under description,) when obtained by the slow evaporation of the satu- rated solution, formed tufts, which were imperfectly crystalline. When drops were allowed to evaporate on a glass plate, the crystalline character was also perceived; but when the salt was deposited rapidly from its hot saturated solution, it appeared in the form of a soft granular mass. When dry, it was white and soft, not changing in the atmosphere. It was readily soluble in water and icohol, but was not affected by ether. Its taste was decidedly bitter. When heated in the air on platinum foil it burnt with a bright smoky flame, like naphthaline, sending flocculi of carbon into the atmosphere, and leaving a mixture of charcoal, sulphuret of barium, and sulphate of baryta. i After being heated to 212° for some time, the, salt appeared to be perfonti dry, and in that state was but very slightly hygro- 1826.} and Naphthaline, and on a new Acid produced. . 209 metric. _When heated in a tube, naphthaline was evolved; but the substance could be retained for hours at a temperature of 500° F. before ‘a sensible portion of naphthaline had separated : a proof of the strength of the affinity by which the hydro-carbon was held in combination. When a higher temperature was appr nds the naphthaline, after being driven off, was followed by a little sulphurous acid, a small portion of tarry matter, and a carbonaceous sulphate and sulphuret. were left. : _ This salt was not affected by moderately strong nitric or nitro-muriatic acid, even when. boiled with it; and no preci- pitation of sulphate took place. When the acids were. very strong; peculiar and complicated results were obtained. When put into an atmosphere of chlorine, at common temperatures, ‘it was not at all affected by it. Heat being applied, an action between the naphthaline evolved, and chlorine, such as might be expected, took place. a a “ie When a strong solution of the pure acid was poured into a strong solution of muriate of baryta, a precipitate was formed, in consequence of the production of this salt. It was re-dissolved by the addin of water. ‘The fact indicates that the affinity of this acid for baryta is stronger than that of muriatic acid. _ The second, or glowing salt of baryta, was obtained in small crystalline groups. The crystals were prismatic, colourless, and transparent: they were almost tasteless, and by no means so soluble either in hot or cold water as the former salts. They were soluble in alcohol, and the solutions were perfectly neutral. When heated on platinum foil they gave but very little flame, burning more like tinder, and leaving a carbonaceous mixture of sulphuret and sulphate. When heated in a tube they gave off a small quantity of naphthaline, some empyreumatic fumes, with a little sulphurous acid, and left the usual product. This salt seemed formed in largest quantity when one volume of naphthaline and two volumes of sulphuric acid were shaken | together, at a temperature as high as it could be without. char- ring the substances. The tint, at first red, became olive-green ; some sulphurous acid was evolved, and the whole would ulti- mately have become black and charred, had it not been cooled before it had proceeded thus far, and immediately dissolved in water. A solution was obtained, which, though dark itself, yielded, when rubbed with carbonate of baryta, colourless liquids ; and these when evaporated furnished a barytic salt, burning without much flame, but which was not so crystalline as former specimens. No attempt to form the glowing salt from the flaming salt, by solution of caustic baryta, succeeded. _ _ Strontia. The compound of this earth with the acid already described very much resembled the flaming salt of baryta. When dry it was white, but not distinctly crystalline: it was soluble in water and alcohol; not alterable in the air, but when New Series, vOL, x11. Pp 210 Mr. Furaday on theMutual Action of Sulphuric Acid [Szpv. heated burnt with a bright flame, without any red tinge, and left a result of the usual kind, = . eOre Gt ' Lime gave a white salt of a bitter taste, slightly soluble in water, soluble in alcohol, the solutions yielding imperfect crys- talline-forms on evaporation: it burnt with flame; and both in air and in tubes, when heated, gave results similar to those’ of the former salts. — 14 _ Magnesia formed a white salt with a moderately bitter taste ; crystallizing m favourable circumstances, burning with flame, and giving such results by the action of heat as might be expected. Tree ' | | | fron. ‘The metal was acted upon by the acid, hydrogen being evolved. The moist pratpiilde being dissolved in the acid gave a neutral salt capable ofcrystallization. This by exposure = air slowly acquired oxygen, and a portion of per-salt was ound, , / Zine was readily acted upon by the acid, hydrogen evolved, and a salt formed. The same salt resulted from the action of the: acid upon the moist oxide. It was moderately soluble in hot water, the solution on cooling affording an abundant crop of acicular crystals. The salt was white, and unchangeable in the air; its taste bitter. It burnt with flame, and gave the usual results by heat. : ie: Lead. The salt of this metal was white, solid, ‘crystalline, and soluble in water and alcohol. It had a bitter metallic taste, with very little sweetness. The results by heat were such as. might be expected. 7 : Suite ‘Man anese. The protoxide of this metal formed a neutral crystalline salt with the acid. It had a slightly austere taste,’ was soluble in water and alcohol, and was decomposed by heat, with the general appearances already described. 4 ay Copper. Hydrated per-oxide of copper formed an acid-salt with the acid, and the solution, evaporated in the air, left radiated’ crystalline films. The dry salt, when heated, fused, burnt with flame, and exhibited the usual appearances. Nickel. The salt of this metal was made from the moist carbonate. It was soluble, crystalline, of a green colour, and decomposed by heat in the usual manner. In one instance, an insoluble sub-salt was formed. Silver. Moist carbonate of silver dissolved readily in the acid, and a solution, almost neutral, was quickly obtained. It was of a brown colour, and a powerful metallic taste. By eva- poration it gave a splendent, white, crystalline salt ; not chang- mg inthe air except when heated; but then, burning with flame, and ultimately leaving pure silver. When the solution of the salt was boiled for some time, a black insoluble matter was thrown down, and a solution obtained, which, by evaporation, gave abundance of a yellow crystalline salt. The changes 1896.} and Naphthaline, and ona new Acid produced. 211 which took place, during the action of heat in the moist way, were not minutely examined. t | Mercury. Moist proto-carbonate of mercury dissolved in the acid forming a salt not quite neutral, crystallizing feebly in the air, white, of a metallic taste, not deliquescent, and decomposed with various phenomena by heat. By re-solution. in water or alcohol, and heat, a sub-salt of a yellow colour was formed. ~ The moist hydrated per-oxide of mercury also dissolved in the acid, forming an acid solution, which by evaporation gave a yellowish deliquescent salt, decomposed by heat, burning in the air, and entirely volatile. | 3. Analysis of the Acid and Salts. * When solution of the pure acid was subjected to the voltaic battery, oxygen and hydrogen gases were evolved in their pure state: no solid matter separated, but the solution became of a. _ deep-yellow colour at the positive pole, occasioned by the evo- lution of free sulphuric acid, which re-acted upon the hydro- carbon.. A solution of the barytic salts gaye similar results. The analytical experiments upon the composition of this acid and its salts were made principally with the compound of baryta. This was found to be very constant in composition, could be obtained anhydrous at moderate temperatures, and yet sustained a high temperature before it suffered any change. : A portion of the pure salt was prepared, and dried for some hours on the sand-bath, at a temperature about 212°, Known weights were then heated in.a platinum crucible to dissipate and burn off the combustible matter; and the residuum being moist- ened with sulphuric acid to decompose any sulphuret of barium formed, was heated to convert it into a pure sulphate of baryta. The results obtained were very constant, and amounted to 41-714 of sulphate of baryta per cent. of salt used, equivalent to 27-57 baryta per cent. | Other portions ofthe salt were decomposed, by being heated in a flask with strong nitro-muriatic acid, so as to liberate the sulphuric acid from the carbon and hydrogen present, and yet retain it in the state of acid. Muriate of baryta was then added, the whole evaporated to dryness, heated red-hot, washed with dilute muriatic acid to remove the baryta uncombined with sulphuric acid, and the sulphate collected, dried, and weighed. The results were inconstant; but the sulphate of baryta obtained always much surpassed that furnished by the former method. Judging from this circumstance that the sulphuric acid in the salt was more than an equivalent for the baryta present, many prnceshee were devised for the determination of its quantity, ut were rejected in consequence of difficulties and imperfec- tions, arising, principally, from Va presence and action of so — P ¥ 212 Mr. Faraday on the Mutual Action of Sulphuric Acid (SuPr: much carbonaceous matter, The following was ultimately adopted. A quantity of per-oxide of copper was prepared by heating copper-plates in air and scaling them. A fratcient quantity of pure muriatic and nitric acid was provided, and also a speci- men of pure native carbonate ofbaryta. Seven grains of the salt to be examined were then mixed with seven grains of the pulve- rized carbonate of baryta, and afterwards with312 grains of the oxide of copper. The mixture being put into a glass tube, was successively heated throughout its mass, the gas liberated being passed through a mixture of baryta-water and solution of muriate of baryta. It was found that no sulphurous or sulphuric acid came off, or indeed sulphur in any state. The contents of the tube were then dissolved in an excess of the nitric and muriatic acids, above that required to take up all that was soluble; anda little solution of muriate of baryta was added for the sake of greater certainty. A portion of sulphate of baryta remained undissolved, equivalent to the sulphuric acid of the salt experi- mented upon, with that contained accidentally in the oxide of copper, acids, &c. This sulphate was collected, washed, dried, and weighed. Similar quantities of the carbonate of baryta and oxide of copper were then dissolved in as much of the nitric and muriatic acids as was used in the former experiment ; and the washings and other operations being repeated exactly in the same way, the quantity of sulphate of baryta occasioned by the presence of sulphuric acid in the oxide, acids, &c. was deter- mined. This, deducted from the weight afforded in the first experiments, gave the quantity fenanee: from the sulphuric acid actually existing in the salt. Experiments so conducted gave very uniform results. The mean of many indicated &9 grains of sulphate of baryta for 10 grains of salt used, or 89 grains per cent, equivalent to 30°17 of sulphuric acid for every 100 of salt decomposed. 7 ‘ ee In the analytical experiments, relative to the quantity of carbon and hydrogen contained in the salt, a given weight of the substance being mixed with per-oxide of copper, was heated in a green glass tube. The apparatus used consisted of Mr. Cooper’s lamp-furnace, with Dr. Prout’s mercurial trough; and all the precautions that could be taken, and which are now well known, were adopted for the purpose of obtaining accurate results. When operated upon in this way, the only substances evolved from the salt, were carbonic acid and water. As an instance of the results, 3°5 grains of the salt afforded 11°74 cubic inches of carbonic acid gas, and 0°9 of a grain of water. The mean of several experiments gave 32:93 cubic inches of carbonic acid gas, and 2°589 grains of water, for every 10 grains of salt decomposed, A ere ¥826.]; and Naphthaline, and.on a new Acid produced. 213 On these data, 100-grains of the salt would yield 329°3 cubic inches of carbonic acid, or 153°46 grains, equivalent to 41:9 grains of carbon, and 25°89 grains of water, equivalent to 2°877 grains of hydrogen. Hence 100 grains.of the salt yielded » Baryta, sececcsseces 27°F ceosee 1100 Sulphuric acid ...... 30°17 ...... 85°35 ATOM! iidice de ae cuca! BLO cana SIDS Hydrogen .ecceceses (2817 veces, 813 102°517 In the second numerical column the experimental results are repeated, but increased, that baryta might be taken in the quantity = shape one proportional, hydrogen being unity : and it will be seen that they do not differ far from the following theoretical statement: Baryta .....+s+se05... 1 proportional 78 Sulphuric acid........ 2 ditto 80 Ce ees 20 ditto 120 Hydrogen... .escnee. (8. ditto 8 The quantity of sulphuric acid differs most importantly from the theoretical statement, and it probably is that element of the salt, in the determination of which most errors are involved. The quantity of oxide of copper and of acids required to be used in that part of the analysis, may have introduced errors, affecting the small quantity of salt employed, which when mul- tiplied, as in the deduction of the numbers above relative to 100 parts, may have created an error of that amount. As there is no reason to suppose that during the combination of the acid with the baryta any change in its proportions takes place, the results above, minus the baryta, will represent its composition ; from which it would appear, that one proportional of the acid consists of two proportionals of sulphuric acid, twenty of carbon, and eight of hydrogen; these constituents forming an. acid equivalent in saturating power to one propor- tional of other acids. Hence it would seem, that half the sul- penny acid present, at least when in combination, is neutralized y the hydro-carbon ; or, to speak in more general terms, that the hydro-carbon has diminished the saturating power of the sulphuric acid to one-half. This very curious and_ interesting fact in chemical affinity was however made known to me by Mr, Hennell, of Apothecaries’ Hall, as occurring in some other compounds of sulphuric acid and hydro-carbon, before I had completed the analysis of the present acid and salts; and a similar circumstance is known with regard to muriatic acid, in the curious compound discovered by M. Kind, which it forms with oil of turpentine. Mr. Hennell is, I believe, on the point 214 | Mr. Faraday on the Mutual Action, §c. . (Suv. of offering an account of his experiments to\the Royal Society, and as regards date they precede mine, iuodies to. aagogi It may be observed, that the existence of sulphuric acid in the new compounds is assumed, rather than proved; and that the non-appearance of sulphurous acid, when sulphuric acid and naphthaline act on each other, is not conclusive as to the non- reaction of the bodies. It is possible that part of the hydrogen of the naphthaline may take oxygen from one of the reo ortions of the su ped acid, leaving the hypo-sulphutie aci of Welter and Gay-Lussac, which, with the hydro-carbon, may constitute the new acid. I have not time at present to pursue these refine- ments of the subject, or to repeat the arialyses which have been made of naphthaline, and which would throw light upon the question. Such a view would account fora part of the overplus in weight, but not for the excess of the sulphuric acid obtained, above two proportionals. } The glowing salt of baryta was now analysed by a process similar to that adopted for the flaming salt. The specimen operated upon was pure, and in a distinctly crystalline state. It had been heated to about 440° F. for three hours in a metallic bath. Ten grains of this salt exposed to air for 40 hours creased only 0:08 of a grain in weight. These when converted into sulphate of baryta fe heat and sulphuric acid, gave 4:24 grains. Seven grains by carbonate of baryta, oxide of copper, heat, Xe. gave 6:02 grains of sulphate of baryta: hence 10 gTs. of the salt would have afforded 8°60 grains of the sulphate, equiva- lent to 2°915 grains of sulphuric acid. Five grains, when heated with oxide of copper, gave 16°68 cubic inches of carbonic acid gas, equal to 7:772 grains, and equivalent to 2°12. grains of carbon. The water formed amounted to 1:2 grain equivalent to 0:133 of a grain of hydrogen. : From these data, 106 grains of the salt would appear to furnish | Baryta ...... 28:03 .. 78:0 or L proportional. Sulphuric acid 29°13 .. 81:41 nearly two proportionals. Carbon ..... . 42:40 .. 118°0 approaching to 20 ditto. Hydrogen.... 2°66 .. 7:4 or 7-4 proportionals : 102+22 results not far different from those obtained with the former salt. I have not yet obtained sufficient quantities of this salt in a decidedly crystalline state, to enable me satisfactorily to account for the difference between it and the flaming salt. _ Attempts were made to form similar compounds with other 1826.]) Analyses of Books. 215 acids than the sulphuric. Glacial phosphori¢ acid was heated and shaken in naphthaline, but without any particular results. A little water was then used with another portion of the mate- rials, to bring the phosphoric acid into solution, but no decided combination could be obtained. Muriatic acid gas was brought into contact with naphthaline in various states, and at various temperatures, but no union could be effected either of the sub- stances or their elements. | , Very strong solution of potash was also heated with naphtha- line, and then neutralized by sulphuric acid; nothing more, however, than common sulphate of potash resulted. As the appropriation of a name to this acid will much facilitate future reference and description, I may, perhaps, be allowed to suggest that of sulpho-naphthalic acid, which sufficiently indicates its source and nature, without the inconvenience of involving theoretical views. Arricte V. ANALYSES OF Books. A Description of active and extinct Volcanos, with Remarks on their Origin; their Chemical Phenomena, and the Character of their Products, .as determined~by the Condition of the Earth during the Period of their Formation. Being the Substance of some Pitas delivered before the University of Oxford, with much additional Matter. By Charles Daubeny, MD. FRS. &c. &c. Professor of Chemistry, and Fellow of Magdalen _ College, Oxford.. London, 1826; 8vo. : _ Ir is not many months since we had the satisfaction of laying before our readers an analysis of a work on volcanos by Mr. Poulett Scrope;* it now becomes our duty to notice another publication which has just appeared on the same subject, the plan of which is of a more extended description, as it embraces not only. a theory of volcanic operations, but likewise a detailed statement of the phenomena, both of a geological and chemical nature, which arise from them. : The author informs us, that he was first led to the inquiries which have furnished him with materials for the present work, by a wish to obtain some further evidence with respect to the origin of basalt, the nature of which still continued the subject of warm discussion, during the time at which he was pursuing his studies at Edinburgh. Conscious that all the light that could be thrown upon this question by reference to the charac- ters and relations of trap rocks themselves, had been already * See Annals for January last. - - 216 Analyses of Books. [Serr obtained through the exertions of preceding ‘observers, he determined to take up the subject in‘a different’ point of view, by examining the relations of these rocks to the products of active or acknowledged volcanos, and with this design to begin by making’ himself fully acquainted with the latter class of formations. | t difow “For this purpose, however, a mere examination of hand specimens was not suflicient, the spots themselves were to be visited, and the circumstances of arte B ical position, as well as the nature of the rocks associated, carefully compared with what was seen in the trap districts that had excited so much attention and dispute.” i gto: wf He therefore examined at different intervals the volcanic.rocks of France and Germany; those of Hungary and Styria; the greater part of such as exist in Italy and the neighbouring islands ; and the whole series of those which extend throughout Sicily ; thus including in his examination most of the appear- ances of the above kind that are manifest in this quarter of the lobe, except those in Iceland, already made known to us through Sir G. Mackenzie and others; in Greece and Turkey, countries at present but little accessible ; and in the Spanish Peninsula, where a few indications of igneous action have been noticed as occurring. ) ‘ Tk, ar His observations in these countries constitute, in great mea- sure, the contents of the two first lectures, for the author has thought proper to retain this title, as indicating the sections or chapters into which the work is divided, notwithstanding the additional matter introduced since they were delivered, which has swelled all of them to a length far exceeding the legitimate limits of an oral discourse. | We observe, however, with pleasure, an abstract of Beudant’s observations on the trachyte of Hungary, which, notwithstand- ng their interest, have hitherto met with but little notice in this country ; and likewise an account of the ‘almost unexplored volcanic district of Transylvania, communicated by Dr. Boué, a geologist well known from his papers on various parts of France and Germany, and his Geognostical Essay on Scotland. The author’s remarks on Auvergne have already appeared under the form of letters addressed to Professor Jameson, and a short account of the volcanos of Sicily, will be seen in the sketch of the geology of that island, communicated originally to the Bristol Philosophical and Literary Institution, and’ since published in the Edinburgh Philosophical Journal. In other respects, the matter of the first two lectures may be considered new ; but not so that of the third which is engrossed by a large assemblage of facts, compiled from various sources both ancient and modern, with regard to the volcanos that occur in sain of the globe, which have not been visited by the author. ere we meet with a summary of the geological details com- 1826.] Dr. Daubeny on Voléanos. 917 prised in the works of Sir G. Mackenzie and others on Iceland; of the accounts handed down to us with respect to those volcanic eruptions, that have taken place in Greece and the Archipelago ; i of the remarks on those of the Canaries and other islands off the African Coast, which have been communicated by Hum- boldt, Von Buch, and other foreign geologists. Traces of the same agency are shown to exist in Asia Minor, Palestine, Syria, and other countries of the East, and a line of volcanic operations is traced from Kamschatka to Japan, and thence, in an almost uninterrupted succession, to Java, Sumatra, and the Andaman Islands. A few of the volcanos distributed over the Great Pacific, and the Gulph of Mexico, are afterwards noticed; and the whole concludes, by bringing together the results of Humboldt’s inves- tigations on the continent of America. : From this statement of the contents of the first three lectures; it will-be evident,. that we cannot pretend to present to our readers a complete analysis of the work; all we can undertake to do, will. be to give an idea of the manner in which the subject is handled, by selecting certain portions for abridgment ; and we shall begin by noticing the author’s description of the volcanos that occur. in the neighbourhood of the Rhine. : . These are divided, according to his usual system, into post- diluvial and ante-diluvial; by which terms, however, nothing more is intended, than an: expression of the fact, that the erup- tions took place, after or before the period at which the valleys were excavated. : erie ) The volcanos of the Eyfel district, which intervenes between the Rhine and the frontier of the Netherlands, furnishes us with an instance of volcanos formed subsequently to that epoch. ‘Scattered over the greater part of the district alluded to, are a number of small conical eminences, often inclosing craters, the declivities of which are usually sunk much below the present level, and have thereby, in many cases, received the drainage of the surrounding country, thus forming a series of lakes, known by the name of Maars, which are remarkably distinguished from those elsewhere seen, by their circular form, and by the absence of any apparent outlet for their waters. The sides of these craters seem to be made up, of alternating strata of volcanic sand and scoriform lava, dipping away in all directions from the centre, at a considerable angle, and the same kind of material has in many instances so acctimulated round the cones, as to objiterate in great measure the hollow between them, and to raise the level of the country nearly up to the brim of the craters.” The author proceeds to a detailed description of certain of these craters, and of the accompanying streams of lava, in which, however, we have not room to follow him; and concludes, as he 218 Analyses of Books...’ (Serr. has done in the case of the modern volcanos 6f Auvérgne, that although of post-diluvial origin, they were in action before the existence of historical records, There is, indeed, a passage in Tacitus, which has been supposed to refer to something ofa volcanic nature that occurred in. this district; but our author ridicules such an idea, and concludes ‘that nothing more was meant, than an accidental conflagration, caused, perhaps, by setting fire to the woods or heaths, in a dryseason. ing “Tt is certain at least that the lava of Niedermennig: existed in the time of Augustus, for the pillars of the ancient Soret of Treves are formed of this material. E | “We are, therefore, under the necessity of attributing to the Eyfel volcanos a date historically very ancient, though, geologi- cally speaking, modern, since geological research may be said almost to terminate where history begins: if we adopt’ the opinions of Prof. Buckland respecting the excavation of the valleys, we must suppose these rocks to have been formed, like some of those in Auvergne, subsequently tothe Deluge recorded by Moses ; or if, limiting ourselves to those views in which all , a concur, we choose to speak more indefinitely, the ate of their eruptions must be pronounced to be posterior to the event which reduced the surface of the globe to its present condition.” P. 65, 8 Debi ‘ort The remaining volcanic rocks in this part of Europe, appear to be of an older date, and are shown by the author to belong to that period in the history of the globe, during which the rocks oallad tertiary were being deposited. The trachytes and basalts of the Seven Mountains’ near Bonn, of the Westerwald near Cobientz, and of several other chains of mountains in the same neighbourhood, belong to this class. ‘The mode oftheir forma- tion is illustrated, by considering certain conical masses’ of basalt, which occur detached in Hessia, the structure and rela- tions of which are sufficiently exposed, to allow of their being studied with exactness. | . leegi In the case of the Pflasterkaute near Eisenach, ‘ the exca- vations are carried to such a depth, that we are enabled distinctly to see the basalt more than 50 feet below the surface of the sandstone. The line of junction is also well-displayed, and we observe the sandstone changed from an horizontal to a vertical position, split in all directions, and rendered harder and whiter, where the basalt touches it.” P. 72. In another case, the portions of sandstone ‘form clusters of little prisms, possessing even greater regularity of form than those of the bastilt which encircles them. “ It is curious,” remarks our author, ‘to trace the resemblance’ between the prisms here alluded to, and those produced artificially in several parts of Derbyshire and Yorkshire, where the soft friable sand- 1826.] Dr..Datibeny on Voleanos. 219 stone of the country, is rendered serviceable for road-making by exposure to heat, which hardens and causes it to split into small columnar concretions.” P. 73. - The hill called Blaue Kuppe, near Eschwege, illustrates these phenomena in a still more striking manner, and it is certainly surprising, that with such phenomena almost in their neighbour- hood, the geologists of the Freiburg school should so long have remained unconvinced of the igneous origin of basalt. . We have no room for the sketch of the trap formations in other parts of Germany, with which the first lecture concludes ; neither can we notice the abstract, given at the commencement of the second, of Beudant’s researches in Hungary. The author agrees with that geologist in opposition to Humboldt, in attri- buting a different origin to the trachyte of Hungary, and to the | older porphyry which supports it; but he combats the theory advanced by the French naturalist, with respect to the formation of the alum diffused through the substance of many beds in this formation. This M. Beudant regards as the result of sulphu- reous exhalations; Prof. Daubeny as arising from the decom- position of metallic sulphurets. 7 - Our author takes pains to show, that every one of the volcanic districts, already noticed, are, at the least, as modern as the tertiary class of deposits ; such is likewise the case with the little. trachytic formation which he visited in Styria, and with the greater part of the volcanic products that occur in Italy. Those of the Vicentin, and of the neighbourhood of Rome are, treated of atsome length ; andinthe Neapolitan territory a volcano is introduced to our notice, scarcely .known, we believe, to English geologists, that, namely, of Mount Vultur. _ The neighbourhood of Naples is of course more particularly dwelt upon, and its volcanos are treated, first, historically; and, secondly, with reference to their geological and chemical phe- nomena. Under the first of these heads, must be placed the question, as to whether Vesuvius was burning at any period of Roman history antecedent to the Christian era; and with the view of deciding this point, our author has brought together many passages from classical writers, in which mention is made of the mountain. Of these, the one most illustrative of its actual structure, at that period,is the account given of the occu- pation of these heights by the gladiators under Spartacus, and of the manner of their escape from this position. We may remark, that Dr. Daubeny differs from former geologists, with respect to the formation of the dykes of Monte Somma, ‘and seems loth to admit, that we have any decided case, in which dykes have been formed within the crater of any volcano, or since the commencement of the present order of things. _ When speaking of the Solfatara, he takes occasion to discuss the origin of those saline products, found within the craters of 220 Analyses of Books. [Supr. most volcanos : the following is the manner in which he accounts for the production -of sal.ammoniac which is.so frequent an ingredient, hy aOhiaS “‘The rock of this mountain is a sort of trachyte, which, besides a little potass, consists essentially of silex and alumine, with an occasional admixture of iron, lime, and magnesia. : “The muriatic acid (exhaled from the volcano) acting. upon these ingredients, forms severally with them, a quantity of” iis matter, proportionate to that in which it is emitted, but the most abundant salt of this class, is the muriate of ammonia, the form- ation of which may, perhaps, be thus accounted for.. “When muriatic acid is suffered to act upon an alkaline hydrosulphuret, it combines with the base, and separates the sulphuretted hydrogen; very little, however, of the latter exhales in a gaseous condition, but it is for the most part precipitated in the shape of a heavy oil, which is found by analysis to con- sist of one atom hydrogen, and two atoms sulphur. Now as sulphuretted hydrogen consists of one atom of. each ingredient, it follows, that the formation of this body. must be accompanied by the disengagement of an equal volume of hydrogen gas. But what becomes of this latter body, since it is not to be detected afterwards in a separate state? It is probable that it has united with the oxygen of the atmosphere, or with its sts. 063 perhaps indeed with both; in. the latter case, the presence of the ammonia is explained ; in the former it is ren- dered more comprehensible, since we have many examples in which nitrogen, in its nascent state, is known to unite with hydrogen, held in combination by weak affinities.” P. 168. The crater of Volcano, one of the Lipari Islands, is in a state somewhat similar to that of the Solfatara. Our author describes, however, the process there going on as so far different, inasmuch as the vapour given out in the crater of Volcano consists of sulphurous acid ; whereas in that of the Solfatara, it was com- posed of sulphuretted hydrogen. The operations, too, of the former appear to be going on with much greater vigour than those of the latter, an exhibit, says our author, perhaps the nearest approximation to a state of activity, during which a descent into the crater would have been practicable. “Nor (he continues) can I imagine a spectacle. of more solemn grandeur, than that presented in its interior, or conceive a spot better calculated to excite, in a superstitious age, that religious awe which caused the island to be considered sacred to Vulcan, and the various caverns below as the peculiar resi- dence of the god.” : Quam subter, specus, et Cyclopum exesa caminis Antra Etnea tonant, validique incudibus ictus Auditi referunt gemitum, striduntque cavernis Stricture Chalybum, et fornacibus ignis anhelat Volcani domus, et Vulcania nomine tellus. 1826.) Dr. Daubeny on Volcanos. 22) “To me, I confess, the united effect of the silence 'and soli- tude of the spot, the depth of the internal cavity, its precipitous and overhanging sides,.and the dense sulphureous. smoke, which, issuing from all the crevices, throws a gloom over every object, proved more impressive than the reiterated explosions of ee contemplated at a distance, and in open day.” B19}: yey _ This lecture concludes by an account of the volcanic forma-~ tions of Sicily, which are divided, like most of the rest, into those of ante-diluvial and post-diluvial origin. The. former are chiefly found in the. Val de Note, but our author observes, that there are certain rocks in the vicinity of Mount. Etna, that were probably formed antecedently to. the mountain at whose foot they lie. The Cyclopean Islands, for instance, (with which every classical reader is acquainted, as the rocks which Polyphemus is described by Homer, as hurling against the bark, in which Ulysses and his crew were taking their flight,) “though now detached, must at one period have formed a connected stratum, for they are covered with a bed of marl, which seems evidently to have been continuous from the one to the other of these islands. This circumstance, and their general compactness, prove that these formations took place under the surface of water. «......e+e00e+e+-Nothing of this kind: is indicated by the structure of Etna.. This mighty and imposing mountain, which rises in solitary grandeur to the height of above 10,000 feet, and embraces a circumference of 180 miles, is entirely composed of lavas, which, whatever subordinate differences may exist between them, all possess the appearance of having been ejected above the surface of water, and not under pressure. - , “Tn the structure of this mountain, every thing wears alike the character of vastness. The products of the eruptions of Vesuvius may be said almost to sink into insignificance, when compared with these coulees, some of which are four or five miles in breadth, 15 in length, and from 50 to 100 feet in thick- ness, and the changes made upon the coast by them, is so consi- derable, that the natural boundaries between the sea and land may be said almost to depend upon the movements of the volcano. “ The height, too, of Etna is so great that the lava frequently finds less resistance in piercing the flanks of the mountain, than in rising to its summit, and has in this manner formed a number of minor cones, many of which possess their respective craters, and have given rise to considerable streams of lava. “Hence, an ancient poet has very happily termed this volcano the parent of Sicilian mountains, an expression strictly applicable to the relation which it-bears to the hills in its immediate neigh- 999 Analyses of Books.- [Szrr. bourhood, all of which have been’ formed by successive ejec- tions of matter from its interior. | jagatter # “The grandest and most original feature indeed in the physiog- nomy of Etna, is the zone of subordinate volcanic hills, with which it is encompassed, and which look like a court of subal- tern princes waiting upon their sovereign. = 7 Ried “ Of these, some are covered with vegetation, others are bare and arid, their relative antiquity being probably denoted by the progress eter has made upon their surface; and the extra- ordinary difference that exists in this respect, seems to indicate that the mountain to which they owe their origin must have been in a state of activity, if not at a period antecedent to the commencement of the present order of things, at least ata dis- tance of time exceedingly remote.” P. 204. began terse senna The Professor then exposes the mistake’ into which Brydone was led by the Abbe Recupero, with regard to the existence of vegetable mould, ‘intervening between the beds of lava at Jace Reale, thus overturning the argument founded on the above fact, which that lively writer has brought forward, to prove the great antiquity of the eruptions of this volcano. Here, however, there is the less necessity for following him, as the details may be seen in Dr. Daubeny’s Sketch of the Geology of Sicily, published in a contemporary journal. | | now In the third lecture we are glad to find an abstract of Von. Buch’s valuable Memoirs on the Canary Islands, which, having never been translated into our language, remain in some measure a sealed book to English geologists. : | Dr. Daubeny has shown the probable existence of volcanos in the East, from many concurrent circumstances. Thus the accounts of volcanic matter in Asia Minor, and the occurrence of a Grotto del Cane near Smyrna, described by Strabo, and rediscovered by Chandler; the correspondence between the traditions that existed in Persia and Greece with respect to the supposed volcano of Demayend in the former country, and those of Sicily and Campania ; the analogy between the Typhceus of the Greek poets and the Zohag of the Zend-Avesta; the frequent allusions to volcanic phenomena in Holy Writ ; and, above all, the destruction by fire of the five cities in the plain o Siddim, all tend to establish the operation of subterranean fire in these countries, at a period, which, (geologically speaking,) must be accounted modern. Fle even explains the formation of the Dead Sea, by imagining a stream of lava to have flowed across the river Jordan, and to have obstructed its channel, which in all probability extended at some former period to the Red Sea, as the late interesting researches of Burckhardt have indicated. Dr. Daubeny shows that there is nothing contrary to analogy 1826.}. Dr. Daubeny on Volcanos. 993: in such a supposition, for we have instances of lakes formed ina similar manner, in Auvergne, if not near the Rhine; and remarks,’ that, “if the little rivulet that flows at the foot of the Puy de la’ Vache in the former country was adequate to produce the lake’ of Aidat, there seems no disproportion in attributing to a river of the size of the Jordan, to say nothing of other streams nowise' inconsiderable which must have been affected by ‘the same’ cause, the formation of a piece of water, such as:the Dead Sea; which, according to the best authorities, is, after all, not more’ than twenty-four leagues in length, by six or seven in breadth.” P. 287. eee ai! as In his account of the volcanos of the New World} it will be’ seen that the Professor concurs with Humboldt, with respect to’ the formation of Jorullo ; indeed the views of that naturalist,’ though expressed, perhaps, in language more metaphorical, like that employed by the Roman poet in speaking of the sudden’ rise of the Promontory of Trezue m Airgolis,* are, upon 'the’ whole, conformable with those entertained by our author, relative’ to the origin of the dome-like masses of trachyte in Auvergne, and éven the basaltic dykes, (if they may be so called,) of Hessia. The three first lectures or chapters, being occupied by a detail of facts with regard to volcanos, the author proceeds, in the fourth, to some general conclusions on the phenomena them-. selves. ay He begins, by considering the theories which have been ‘pro- posed to explain the cause of volcanos, and haying decided in favour of the one suggested by Sir H. Davy’s discovery, with respect to the metallic bases of the earths and alkalies, endéa- vours to deduce, in detail, the phenomena attendant on an eruption from this hypothesis. : hah “ Let us suppose,” he says, “that the nucleus of the earth at _ a depth of three or four miles either consists of, or contains as a. constituent part, combinations of the alkaline and earthy metal- loids, as well as of iron, and the more common metals, with sulphur, and possibly with carbon. : sel tert: “These sulphurets are gradually undergoing decomposition, wherever they come into contact with air and water, but, defended by the crust of the globe, just as a mass of potassium is by a coat of its own oxide, when preserved in a dry place, the action goes on too slowly to produce any striking effect, unless the iatter of these agents be present in sufficient quantity, __ “‘ Hence, under our continents, the elastic fluids generated by this process are compressed by the superincumbent mass of rock, until they enter probably, into new combinations, or diffuse themselves through the solid strata. *-Extentam tumefecit humum, ceu spiritus oris Tendore vesciam solet, aut derepta bicornis Terga capri,—Ovid, Metam. 224 Analyses of Books. [Sert. . But under the sea, where the pressure of an enormous column of water assists in forcing that fluid through the minutest crevices, of the rock, the action must go on more rapidly, and the effects consequently be of a more striking nature. . “ These effects, however, will take place in the middle of the sea less generally than on the coast, because the pes of the ocean itself opposes,an impediment; and it will in general not be constant, but intermittent, because the heat generated by the process itself, will have a tendency to close the aperture by which the water entered, first, by injecting the fluid lava into the fissure; and, secondly, by causing a general expansion of the rock; nor will the water again find admission, until, owing to. the cessation of the process, the rock becomes cool, and consequently again contracts to its original dimensions.” . “ Now the first effect of the action of water upon the alkaline and earthy metalloids, willbe the production of a large volume of hydrogen gas, which, if air be present, will combine with oxygen and return to the state of water; if it be absent, will probably combine with the sulphur, both being at the high temperature favourable to their union. In the former case, autrogen. gas will be given off; in the latter, sulphuretted rogen. we But in case of the presence of oxygen, the sulphur will also become inflamed, and give rise to the production of sulphurous acid, which will predominate among the gaseous exhalations emitted from the mouth of the volcano, provided a sufficient quantity of air be present to combine with the hydrogen, and re-convert it into water. So soon, however, as the oxygen is consumed, the hydrogen, no longer entering into combustion, unites with the heated sulphur, and escapes in the form of sul- phuretted hydrogen, which, towards the latter period of the eruption, will predominate over the sulphurous acid, because it continues to be formed, long after the want of oxygen has put a stop to the production of sulphurous acid. Now it is well known, that these two gases mutually decompose each other, and, therefore, cannot exist at the same time, so that the appear- ance of sulphuretted hydrogen from the mouth of the volcano, may indicate, if not the entire absence of sulphurous acid, at the place at which the process takes place, at least that its forma~- tion is stepped by the consumption of oxygen, or is going on with less energy than heretofore. | “The very circumstance of the reproduction of water by the mutual decomposition of these. two gases, might be the means of keeping up the action, in a languid manner, for an indefinite period. ‘The slowness with which lava cools, would cause it to _ give out, for a considerable time, sufficient heat to the adjoining strata, to place the sulphur at the temperature necessary to cause its combination with oxygen; hence a certain portion of 1826.) Dr. Daubeny-on Volcanos. 225: sulphurous acid would'be continually emitted, which, however, would, be soon) decomposed -by the \hepatic gas present. : The water resulting /from this) process, would percolate ; into) the, recesses of the rock, act upon any portions of the alkaline and earthy metalloids, that might have escaped the original action, , and give birth to a fresh volume of hydrogen gas, ready in its turn to dissolve.a new portion of sulphur, and) thereby to contti-. bute to,a repetition of the same phenomena.” P.392..... |... We have no room for further extracts, but must proceed |to, give some account of the second: department of, the inquiry 5; namely, as to the degree in which: volcanos, have contributed towards the production of the older constituents of our globe. » He decides in favour of the general, if. not’ the universal: volcanic origin of trap, by considering the analogy in chemical. and geological characters that exists between it, and lava, and. by accounting for the distinctions between the,two, from the differences, of circumstances under which they were respectively produced. He even shows, that as these circumstances became more similar to those that exist at present, the characters of the; erupted’ masses approach more’ nearly to. those of. the, actual products of subterranean fire ; and he therefore establishes three. classes. of volcanic formations, the first produced. since. the commencement of the present order of ines ; the second, during the deposition of the tertiaryrocks; the third, cotempo-., raneous with the more ancient strata. Of these, the first class, being formed inthe open air, possesses the characters of bodies exposed’ at: present to artificial heat 5. the third, being of submarine origin, has those characters modi- fied by the influence of great pressure ;_ whilst the second, being formed under water, but under a body of fluid less considerable than existed in the former case, possesses characters intermediate between the other two.’ * ii The author details, at some length, the subordinate differences arising out of these fundamental distinctions, and then proceeds to notice the arguments that have been advanced, both for and against the igneous origin of granite and serpentine, These questions, however, he leaves undecided, or at least considers to require some further elucidation. The author likewise regards the opinion which prevails, as to the increasing heat of the earth from the circumference to the centre, as open to some objection ; and is led from his own observations in mines, to consider their temperature as influenced by local causes in a greater degree than is generally suspected. He concludes by -speculating on the final causes of volcanos, which he regards as the safety-valves, through which elastic fluids, generated by processes going on in the interior of the earth, find a vent, and consequently as the best safecuards - against destructive earthquakes. Sli New Series, vou. X11. oy 226: Analyses of Books, .— [Sepr. He ‘also imagines that volcanos may be among the means, that nature employs for increasing the extent of dry land, in roportion to that of the ocean, a notion rendered more probable; y considering; that coral reefs are mostly founded upon shoals’ catised by volcanic eruptions. ° lend abiolimon valtss *“ Hence a sort of consistency will appear, in this case, to exist’ in the arrangements of nature, which leads to the belief that fire and water are both working together toa common end, and that end the preparation of a larger portion of the earth’s surface for the maintenance of the higher orders of animals.”") 0 © The additional notes relate to a subterraneous noise heard: neat the Red Sea; to the origin of the fables respecting the Typhon or Typheeus of the Greeks, which seem to be often’ meant as allegorical representations of volcanic phenomena; to the- revolutions of opinion that have taken place with respect to’ geological theories; and to some’ other topics.” The whole concludes with alist of books, from which inform-’ ation may be wnat as to the different voleanos, mentioned in the course of thework, © 9 es PoTOta The volume is illustrated with several wood-cuts, giving sec- tions, &e. of geological phenomena, bya copper-plate engraving: xf Jorullo, as represented by Humboldt, and by two maps,’ the’ oné of Mexico, the other of a part of Judea, illustrative of the author’s views with respect to the formation of the Dead Sea.) Philosophical Transactions of the al Society of London, for “IDO Awol 1826. ed Tand ITs i ‘ 1), 5 f ; Grete ' en (Concluded from p. 141.) IT SES. FG GET XII. On the Nervous Circle which connects ihe Voluntary Muscles with the Brain ; by C. Bell, Esq. communicated by the President. ri asha afk? abe hatte: welt og | The principal results of the investigation detailed in this paper, are contained in the following extracts: | “ T hope now to demonstrate—that where nerves of different functions take their origin apart and run a different course; two nerves must uniie in the muscles, in order to perfect the relations betwixt the brain and these muscles. CR Reyes 0% “It may be in the recollection of the Society, that my first paper showed the difference of the nerves of the face ; by divid- ing one nerve, sensation was destroyed, whilst motion remained ; and by dividing the other, motion was stopped, whilst sensibility remained entire. ee a “Other parts of the nervous system since that time have engaged my attention; and it is only now that I am able to make full use of the facts announced in my first paper, which were indeed expected to lead to further improvement of our knowledge of the animal ceconomy. When I distinguished the 1826.] Philosophical Transactions for 1826, Parts I. and IT, 22% two classes of nerves, going to, the muscles of the face, and divided the motor nerve, and when the muscles were deprived of motion by this experiment, the natural question suggested itself+-of what. use are the neryes that remainentire? — _. ‘For a time I believed that the fifth nerve, which is the sen- sitive nerve of the head and. face, did not.,terminate in the substance of the muscles, but only passed through them to. the- skin; and I was the more inclined to this belief on observing, that the muscular parts when exposed in surgical operations did not possess that exquisite sensibility which the profusion of the sensitive nerves would imply, or which the skin really pos- eeasesiis 19130 dogo iii | : | ‘¢ Still dissection did not authorise this conclusion. I traced the sensitive nerves into the substance of the muscles: I found that the fifth pair.was distributed more profusely to the muscles than to the skin ;.and that estimating all the nerves given to the muscles, the greater proportion belonged to the fifth or sensitive nerve, and the smaller proportion to the seventh or motor nerve. On referring to the best authorities, as Meckel,* and my excel- lent preceptor Monro, the extremities of the fifth were described by them as going into the muscles, so that of this fact there cannot be a doubt. - mi Tik : vt i “ Having ina former paper demonstrated that the portio dura of the seventh nerve was the motor of the face, and that it run distinct from the sensitive nerve, the fifth, and observing that they joined at their extremities, or plunged together ito the muscles, 1 was nevertheless unwilling to draw a conclusion from a single instance; and, therefore, cast about. for other examples of the distribution of the muscular nerves. It was easy to. find motor nerves in combination with sensitive nerves, for all the spinal nerves are thus composed; but we wanted a muscular nerve clear in its Course, to see what alliance it would form in its ultimate distribution in the muscle. I found in the lower max- illary nerve the example I required. ) « The fifth pair, from which this lower maxillary nerve comes, as I have elsewhere explained, is a compound nerve ; that is to say, it is composed of a nerve of sensation, and a nerve of | motion. It arises in two roots, one of these is the, muscular nerve, the other the sensible nerve; on this last: division the Gasserian ganglion is formed. But we can trace the motor nerve clear of the ganglion; and. onward in. its course to the muscles of the jaws, and so it enters the temporal masseter, pterygoid, and buccinator muscles. “ If all that is necessary to the action of a muscle be a nerve to excite to contraction, these branches should have been unac- companied; but on the contrary, I found that before these ‘6 * Meckel de quinto pare nervorum cerebri.” Q2 228 Analyses of Books. - . [Serr motor nerves entered the several muscles, they were joined by branches of the nerves which came through the Gasserian gang- lion, and which were sensitive nerves. . *<] found the same result on tracing motor nerves into the orbit, and that the sensitive division of the fifth pair of nerves was transmitted to the muscles of the eye, although these muscles were supplied by the third, fourth, and sixth nerves. « “A circumstance observed on minute dissection remained unexplained,—when motor nerves are proceeding to several muscles they form a plexus; that is, an interlacement and exchange of fibres takes places : “The muscles have no connexion with each other, they are combined by the nerves ; but these nerves, instead of passin betwixt the muscles, interchange their fibres before their distri- bution to them, and by this means combine the muscles into classes. The question therefore may thus be: stated: why. are nerves, whose office it is to convey Sensation, profusely. given to muscles in addition to those motor nerves which are given to excite their motions? and why do both classes of muscular nerves form plexus ? fit 07 “To solve this question, we must determine whether muscles have any other purpose to serve than merely to contract under the impulse of the motor nerves, For if they have a reflective influence, and if their condition is to be felt or perceived, it will presently appear that the motor nerves are not suitable inter- nuncii betwixt them and the sensorium. fant Je 1 ; v3 “ I shall first inquire, if it be necessary to the governance of the muscular frame, that there be a consciousness of the state or degree of action of the muscles? That we have a sense of the condition of the muscles appears from this: that we feel the effects of over exertion and weariness, and are excruciated by spasms; and feel the irksomeness of continued position. We possess a power of weighing in the hand :—what is this: but. estimating the muscular force? We are sensible of the most minute changes of muscular exertion, by which we know. the position | of the body and limbs, when there is no other means of know- ledge open to us. Ifa rope-dancer measures his steps OY: the eye, yet on the other hand a blind man can balance his body. In standing, walking, and running, every effort of the voluntary power, which gives motion to the body, is directed by a sense of the condition of the muscles, and without this sense we could not regulate their actions. : “Tf it were necessary to enlarge on this subject, it would be easy to prove that the muscular exertions of the hand, the eye, the ear, and the tongue, are felt and estimated when we have perception through these organs of sense; and that without a sense of the actions of the muscular frame, a very principal inlet to knowledge would be cut off. b, Pigtig #8 “ Tfit be granted, that there must be a sense of the condition 1826.] Philosophical, Transactions for 1826, Parts I. and IT.229 of the muscle, we have next to show that a motor nerve is not a conductor towards the brain, and that it cannot perform the office of a sensitive nerve. © ).. Deoe yi « Without attempting to determine the. cause, whether depending on the structure of the nervous cord, or the nature, or the source of the fluid contained, a pure or simple nerve has the influence propagated along it in one direction only, and not backwards and forwards; it has no reflected operation orpower retrograde ; it doesnot both act from and to the sensorium. ‘* Indeed reason without experience would lead us to conclude, that whatever may be the state, or the nature of the activity of a motor nerve during exertion, it supposes an energy proceeding: from the brain towards the muscles, and. precludes the activity _of the same nerve in the opposite direction at the same moment. It does not seem. possible eae that a motor nerve can be - the means of communicating the condition of the muscles to the brain. . He aul Gera we ‘Expose the two nerves of a muscle; irritate onejof them, and the muscle will act; irritate the other, and the muscle remains at rest. Cut across the nerve which had the power of exciting the muscle, and stimulate the one which is undivided —the animal will give indication of pain; but although the nerve be injured so as to cause universal agitation, the muscle with which it is directly connected does not move. Both nerves being cut across, we shall still find that by exciting one nerve the muscle is made to act, even days after the nerve has been divided ; but the other nerve has no influence atall. — , _“ Anatomy forbids us to hope that the experiment will be as decisive when we apply the irritants to the extremities of the divided nerves which are connected with the brain; for all the muscular nerves receive more or less minute filaments of sensi- tive nerves, and these we can trace’ into them by the knife, and consequently, they will indicate’ a certain degree of sensibility when hurt. To expose these nerves near their origins, and before any filament of a sensitive nerve mingles with them, requires the operator to cut deep, to break up the bones, and to divide the blood-vessels. All such experiments are much better omitted; they never can lead to satisfactory. conclusions.” Ea * O) poles a % ae HU “ Between the brain and the muscles there is a circle of nerves ; one nerve conveys the influence from the brain to the muscle, another gives the sense of the condition of the muscle'to the brain. if the circle be broken by the division of the motor nerve, motion ceases; if it be broken by the division of the other nerve, there is no longer a sense of the condition of the muscle, and therefore no regulation of its activity.* | ' - *#* Thus led to conclude that there is motion in a circle, we nevertheless cannot adopt the hypothesis of circulating fluids. Thata fluid does not proceed from the brain, 930...» Proceedings of Philosophical Societies; [Serr « We have noticed, that there is a plexus formed both ‘on the nerves which convey the will to, the muscles; and on: the nerves which give the sense of the condition ‘of' the’ muscles. “The ~ peqson of this I apprehend to be that the nerves must correspond with the muscles, and consequently with one another. If the motor nerve has to arrange the action ofseveral muscles 80 as to produce a ney of motions, the combinations must be formed by 'the interchange of filaments among’ the nerves before they enter the muscles, as there is no cofinexion between the muscles themselves. » As the various combinations of the muscles have a relation ‘with the’ motor nerves, the’ same rela- tions must be established by those nerves which eonvey the impression of their combinations, and a similar plexts ‘or inter- chanee of filaments therefore characterizes both’? °° XII. On the Constitution of the Atmosphere; "by John Dalton, Esq. PRS. &6.05 0 : OUST TOS Ty sensi 9} The Annals for April, p. 289, contains an abstract of this communications 9 6 19st OWS SU BROW 5, i . abs eS RS ie. i>... Arrticte VI, “Proceedings of Philosophical Societies... | “ASTRONOMICAL SOCIETY. — ng *~ June9.—The reading of the Rev. Féaron Falows’s paper onthe Small Transit Instrument, was concluded. Mr. Fallows’s direc- tions may be comprehended briefly in the following particulars: 1. Place the transit instrument as near the meridian as possible, and also substantial. meridian-marks at a considerable distance both to the north and south. 2,. The clock must be set forward to sidereal time, and its daily rate obtained. Th Ailes of pairs of high and low Greenwich «stars must be made each evening, along with others whose right ascensions are required, 4, The apparent right ascensions of the Greenwich stars must be computed up to the time of observation, or taken from, the Nautical Almanac. 5, The azimuthal error must be found, if possible, by several pairs of those. Also, 6. The error of the ‘clock at the transit of one of the Greenwich stars. _7. Reckon this error constant to every observation made during the same night. 8. The azimuthal error must be considered, with a,con- trary algebraic sign, for stars between the zenith (of the Cape) we voor ge from this; that on touching the end of a motor nerve which has been some days separated from the brain, the muscle is excited as when the nérve was first divided. The property, however it may be defined, is therefore in the nerve. Our language might perhaps be made more precise if we used terms which implied the ‘course of nervous influence, whether from or towards the brain ; but ‘it will be difficult 4o express this without the aid of hypothesis,” ww mat IY 1826] soo istronomteads Societys os..0. 231 and the pole. 9.. A. proportional part of the daily rate must be applied: to every observation from .the first. .10,.'The. error, of each star from the true meridian, must be 2h hn from tables © ‘ee @&e 8 4 * » @e @ @ @ se circle described by the pole-star, the state of the barometer and thermometer being given, minus the refraction due to that alti- tude. The last correction he regards as altogether arbitrary, and states that he employs Bradley’s refractions.. ‘The obser- vations of the last eighteen months at Greenwich, with the two circles, as described in a former paper, include 720 of the pole- star, from which the co-latitude deduced is 38° 31’ 217-045. ~ ‘There was next read, “A Summary of the Observations made for the Determination of the Latitude of the Observatory ‘at Wilna, by M. Slawinski.” . The. observations amount to 260, and were made in the months.of October and November, 1825. The author gives an account of his researches to determine the flexure in the repeating circle, and explains that his reductions are made, both by means of the places of stars given in Bessel’s Tables, and the positions announced in the Nautical Almanac for - 1827. The latitude referred to the centre of the transit instru- ment is 54°40’ 59-09 deduced by.comparison with Bessel, and 54° 41’ 0-05 by comparison with Naut. Alm. The greatest of these determinations is less by about 2” than the latitude’ of the same observatory, as given by M. Slawinski’s. predecessors, Poczobut and Sniadecki,. , The reading of M. Slawinski’s paper, was followed by that, of cone on ‘ Micrometrical: Observations .of the Planet. Saturn, aade with Fraunhofer’s large Refractor at Dorpat, by Professor Struve.” These observations were made with a refracting wire ‘micrometer attached to Fraunhofer’s large telescope, now so well- 232 Proceedings of Philosophival-Societies. [Ser'r. known, employing the peut 540: \ Professor .Struve describes both the instrument and ‘the manner of observation; ‘but it’ will psc ‘simply necessary here to record ‘the pene wih the pinilots istance; which are’as below: viz. | oi 1. The external diameter of the dacutial ming = 40215 2. internal ee ME Oe ae ee Oe 3. external ~ es Internal rmg 34 +579 — 4, - internal ©" i aivto, 96 ‘748 5. ‘equatorial diameter of Sein sreseeseee 18 *045 ° 6, breadth of the external TING... eco ceetes 2 SLO’ cg ditto aK | “chasm meine e 0 “408. m aiatgy, the singe i Bo ORG ee! Se miternal ring”) 9d 915" 9. Distance of the ring from Saturn’, ........... 4°352 © 10. The equatorial radius of Saturn. .....0...... (9 022" The mean, value of the inclination of the ring to the ecliptic, i is 98° 5-9, witha probable error not exceeding fe M.Struve has detected .no trace of a er 4 the ring into many, parts ; but. he observes that the outer ring is much less brilliant than the inner. The five longest-known satellites are readily. distinguished, through Fraunhofer’s telescope, even in the Nsatoate field. The 4th appears like a small he diame ter 07-75, . M. Struve saw the “bth several times ; but he has never seen,.the 7th; of whose existence indeed Schroeter enter- tains doubts. . The.same p ape, ly details the results of micrometrical measurements of Jupiter and its satellites, made with the same instruments, and. are the same power 540, or from thence to 600... The mean results at the mean distance of the planet from: the earth, are, . de 1, Jupiter’ $ major axis. ‘ia ay xa 38/442 JM Quits minor axis. wewieieie BO G45. «| ‘i or compression . Jove 0.0728 or WL? Mebnciimm, Y’s Ast he io a OSB 01 at ny Bs 2d) ¢ 083? Q :914 .. opr A | « 3d 1 :492 mi Ti ) root: of bows lhe 22% Schroeter and Harding have often imagined, that they have detected a deviation of Jupiter from the elliptical form; and so thought Struve at first ; but a closer examination enables him to explain the illusion. On March 7th this. year, he thought the di ameter which extended from 61°4 lat. preceding S. to 61°4 lat. following N. was obviously smaller than the ellipsis would allow. But the micrometric measurement proved that that was not.the case. | That evening the major axis, A, was 44”-75; the minor axis, B, was 41-72; and the diameter’i m . ‘question taken with the same micrometer was 42/34, Calling 1826. “0 Astronomical Society. © > 533 this’ diameter 7, and the ‘latitude on the planet, /, we have x= — One: ——, and the nuimerical result is ¢ = 42”-38, CAR sin? 14+ BY e082)? ta ese severe ge platen aaes differmg only 004 from the measurement. | Most'probably it is the slanting position ofthe axes of the ellipse, with regard to the vertical circle, which causes this illusion. pwn ee nen “Lastly, ‘there was terminated:on the same evening, an «Account of’ some Observations made with a Twenty-feet Reflecting Telescope, by J. F. W. Herschel, Esq. Sec. RS. and For. Sec. of this Society.” This valuable communication is divided into’ four sections. The first contains descriptions and approximate places of 300 new double and triple stars. ‘The telescope with which the observations were made, is one of the ‘front view” construction; aperture 18 inches, focal length 20 feet. It was constructed in the year 1820, under the joint superintendence of Mr. Herschel’and his venerable father. Its light, with its full apérture, enables it to reach the faintest nebule of the third class, while, with an aperture of 10 or 12 inches, it serves to define double stars of the first class of an average degree of closeness.. Mr. Herschel briefly describes the method of differences employed in sweeps of the heavens, the modifications introduced into the’ process on‘ ‘account of Mr. Herschel’s being deprived of the valuable assistance of his aunt, Miss Caroline Herschel, his classification and characteristics of the magnitudes of the stars from the 7th to the 20th inclusive, of which none of the last three can be seen with the least illumina= tion, but comprehend the stars seen or suspected in resolvable nebule. Mr.-H. then presents an example of the method, in which the business of “a sweep” is conducted, and of the method of obtaining from it the approximate right ascensions and polar distances of the objects which it comprises ; accompa- nied by several instructive remarks. The table exhibits, in eight columns, the approximate places of 321 new double and triple stars, for Jan.'1, 1825, with their estimated angles of posi- tion, distances, magiitudes, and other particulars. A great many of the double stars tabulated in this paper, exhibit the highly interesting and curious phenomenon of contrasted colours ; in combinations of white and blue or purple, yellow, orange, or red, large stars, with blue or purple small ones: red and white combinations also sometimes occur, but with. less frequency. In all these cases, the excess of rays belonging to the less refrangible end of the spectrum falls to the share of the large star, and those of the more refrangible. portion to the small, Another fact not less remarkable, and rendering highly probable some other relation than: that. of mere juxta-position, is, that ‘though red single stars are common enough, no example of an insulated: blue, green, or purple one has yet been produced. The three remaining sections of this paper comprise observa- 234 Scientific Notices--Miscellaneous. (Surr. tions of the second comet of 1826 ; an account of the actual state of the great nebula in Orion, compared with the observations of former astronomers; and observations of, the. nebula, in the irdle of Andromeda. The account; of the comet, and that, of e t nebula in Orion, are accomp nied; with illustrative drawings, and the latter also with a kind, of map representir the whole as a constellation, in which, the parts; are named, agreeably to a.rude resemblance which the whole nebula presents to the head, snout, and jaws; of some monstrous animal. Aided by these drawings, the yerbal account presents an instructively perspicuous description of the truly interesting phenomenon to which it.relates. | . ton egonld: eitinr nom -. Articue VIL. SCIENTIFIC NOTICES, | _ MiscktaNnzous. oe 1. Solar Spectrim—Light and Heat. . Pror. Lesxie exhibited some interesting experiments in his Class-room this week, with the view of showing the inaccuracy of the received opinion with regard to the heat of the solar ‘spectrum. Profs. Jamieson, Russel, and Monro, Mr. Adie, opti- cian, Mr. Stevenson, engineer, and several other gentlemen were present. We had also an opportunity of witnessing the experi- ments, the nature of which we shall endeavour to explain, with the help of the following diagrams. 9) 6) Noid 2 fy V ’ 2 R 9 By some experiments made about thirty years ago, Dr. Her- schel was thought to have established a conclusion, which has ever since been regarded as extremely curious. On trying the temperature of the different coloured rays, which form the solar spectrum (V, R, fig. 1), he found diet the heat was me | unequally divided, that it was smallest in the violet rays, V, rather greater in the indigo, and went on increasing through the 1826) Scientific Notices Miscellaneous. - * 886 \ ' ‘blue, green, orange, yellow, and was greatest.of all in the red, R, at the other end. of the spectrum.) But what was most remark- abley ‘the heat was found to extend beyond .the limits of the spectram, “and reached its maxinium, not within the red: rays, dout at'a point sim the:darkspace, about -half an inch “beyond ‘their ‘outer boundary, from which it diminished in’ both direc- ‘tions. ‘This conclusion has been ‘long \received:in Britain as andisputable, and now'finds a place‘in all our elementary: work. ‘on Natural Philosophy... Prof. Leslie) was led, however, to ‘question its accuracy, by an experiment he made»twenty year ago, and which was substantially the same with that made the other day, except that, instead of a common doublesconvex lens, ‘he had now the advantage of employing one of Fresnel’s lenses (surrounded by’ concentric ‘prismatic rings) belonging tw the Northern Lights; with which he was accommodated by Mr. ‘Stevenson. The tesultwas'stated briefly in a note to the article ‘Climate, published in’ the’ Supplement to. the Encyclopedia Britauinica eight years’ avo, but not-in’a way to attract the attention’ which ‘the *subject. merited... The experiment: is remarkably simple, yet extremely well calculated to bring Her- schel’s doctrine to the test. 8 : 0 “oLet L in figure 2 represent a double-convex lens of ‘20:inches ‘diameter. If the middle of this lens (marked by dotted lines) is ‘covered with a sheet of opaque paper, the uncovered rim ¢@2, ‘two inches broad, ‘will forma circular prism, which, if it were ‘extended in a straight line, would be five feet long. Ifthe lens thus covered is exposed to the sun, the rays or pencils of rays a, which pass through the rim) will be refracted exactly as they are in the spectrum, but they necessarily converge; and thus the heat and light of a prism five feet long can be accumulated ina small point. Leta piece of paper be héld at W a little before the focus (or behind, for it answers equally either way), so as to receive the circular ring of light x z, the red rays will be seen at the outside of the ring at 7 (fig. 3, where the dotted lines repre- sent a small segment. of the luminous ring, and X Y the paper) and the violet at the inside, v... The orange and indigo rays may also be faintly discerned ; but as light in a state of great inten- sity always becomes white, of whatever rays it may be composed, so the other colours which should occupy the intermediate space (between v andr), blue, green, and yellow, are lost in one intense and dazzling white. We have here, in short, the colours of the solar spectrum; but inva state of great concentration. Let us now substitute for the piece of paper’a stick of black sealing- “wax, with the surface roughened; and let this be placed across theiluminous ring, in the position W, fig.2, or X Y, fig, 3.- Tn the course of a minute, the surface of the wax begins to shine about y (fig.'3), and then melts. The fusion extends towards v and towards 7, but always stops at the extreme edge of the red 236 Scientific Notices—Miscellaneous. (Serr. rays. Now, if Dr. Herschel’s opinion were correct, the fusion should begin. on the outside of the dotted line, about half-way between r and X, and from this point it should extend inwar towards r and y, and also outwards in the ,opposite direction. The experiment was Po me st many times, but the result was invariably the same. The fusion always began ‘about that. part of the spectral image where the yellow or orange rays are placed; and, on the other hand, when.a plate of wax was placed close to the boundary. of the red.on the outside, where Dr. Herschel says the maximum of heat is found, the fusion never commenced at all. The breadth of the luminous ring was about one inch, -its diameter three or four inches.» i teddy dqooxe Wad yollto This experiment, which is extremely simple, and exempted from many sources of error which attach to, experiments with the thermometer, seems clearly to show, that the maximum of heat is not beyond the red rays as Herschel supposed, but distinctly on the inside of them, Herschel’s doctrine ought, therefore, to be expunged from our scientific ‘treatises ; but perhaps it might beno more than a proper mark of respect to the talents of that eminent philosopher, to repeat his experiments, with, the view of tracing the circumstances that led him into error. The judicious and accurate Haiiy, in his Elementary Treatise published more than twenty years.ago, observes that. Herschel’s experiments stand in need of repetition (Gregory’s Haiiy, ii. 258, 1807); and we learn that when they have been repeated at a more recent period by the French and German philosophers, they have led to different results,. | | } Prof. Leslie’s note descriptive of his experiment will be found in the article Climate, in the Supplement, at the foot of p. 193. —(Scotsman, July 29.) : ; ) 2, Luminous Circle around the Moon. On the 26th of Oct, 1825, at about half-: | past ten in the evening, the following phe- nomenon was observed by two gentlemen at. Kensington,—a faint luminous circle surrounding the moon, not sensibly tinged with any colour, and intersected by a larger one parallel to the horizon, passing through \ the moon, and likewise colourless: The |. circles were not quite continuous in all parts, and there were a few thin clouds: the whole appearance lasted nearly a quar- _ ter.ofan hour.’ Nothing like a paraselene was observed at either of the points of intersection, . | : Se oe eo 1826.] Scientific Notices--Miscellaneous. 237 | 84 Geckoes used: for catching Flies: In Java, the inhabitants rid themselves of flies in their apart- ments by means of Geckoes, a species of lizard, named, from their cry, toké. and gogok, which: continually pursue these insects for the purpose of feeding upon them.—(Edin. New Phil. Journ.) - ated iio) corel uholl 4. Onthe Serpents of Southern Africa. ’ “T have made a great many experiments upon such serpents as I have been able to procure alive, and lave thereby ascer- tained which of them are or are not-poisonous,” and “ by actual experiments I have found, that not a greater proportion than one to six of the species found here are noxious ; we have: three species of the viper, the bites of all of which are bad, though not invariably fatal; also three species of Naia, the bites ofall — of which produce almost certain death; and two species of Elaps; which, from my observations, are also very dangerous.” —(Ex- tract of a letter from Mr. Thomas Smith, of Cape Town, to Prof. Jameson.) . it : 5. Manner of the Serpent-Eater (Gypogeranus) in destroying fet : _ Serpents. : 7 a “Some time ago, as a gentleman was out riding, he observed a bird of the above-mentioned species, while on the wing, make two or three circles, at alittle distance from the spot’ on: which he then was, and after.that suddenly descend. to. the. ground. On observing the bird, he: found it engaged in examining and watching some object near the spot where it stood, which. it continued to do for some minutes. . After that, it moved with considerable apparent caution, to a little distance from the spot where it had alighted, and then extended one of its wings, which it kept in continual motion. Soon after this artifice, the gentleman remarked a large snake raise its head to a consider- able distance from the ground, which.seemed to’ be .what the bird was longing for, as the moment that took-place; he instantly struck a blow with the extremity of the wing, by which he laid his prey flat on the ground. The bird, however, did not yet appear confident of victory, but kept eyeing his enemy fora few seconds, when he found him again in action, a circumstance that led exactly to a repetition of the means already detailed. ‘The result of the second blow appeared, however; to inspire more confidence ; for almost the moment it was inflicted, the bird marched up to the snake, and commenced kicking it with his feet; after which, he seized it with, his bill, and rose almost perpendicularly to a very considerable height, when he let go '. the reptile, which fell with such violence upon the ground, as seemingly to satisfy him, that. he might now indulge himself with the well-earned meal in perfect safety.” From the Same to the Same.—(Edin. Phil. Journ.) 238 Scientific Notices Miscellaneous. (Sept. 6. New Species of North American Quadruped. By Richard Harlan, MD. Professor of Comparative Anatomy to the Phila- delphia Museum, &c. ) Arvicola Ferrugineus. ¢nob.y ~~ Vulgo.— White-bellied Cotton Rat. ° Char. Body large, ferruginous, brown above, whitish beneath ; fore legs very short and slender; tail more than half the length of the body... , Sat: , Saint ga Dimensions. Total length from the snout.to, the root. of the tailiseven inches’; length of the tailfourinches... |... ...... Description... Head. long ; snout, tapering ;, whiskers white, fine}: and sparse, some. long,,others short; ears rather large, broader than long, sparsely ,hairy within, naked without, an- terior borders covered with long hairs—the teeth do not differ essentially from those..of the A.. Aortensis (nob.)* the upper molars are rather, more compressed in their antero-posterior diameter, and the curved lines of enamel on the crowns of the inferior, assume, in some instances, the form of the Greek epsi- lon. Body massive, tapering towards the root of the tail in the same manner, though not to the same degree, as in the Norway rat ; covered with fine long hairs of a dark plumbeous colour, oe with brown, and intermixed with black. Inferior parts of the body plumbeous-white, the hairs being plumbeous, tipt with white; tail slender, tapering, covered with hair, brown above, whitish’ beneath; feet grayish, white anteriorly, in form and structure resembling those of the A. palustris (nob.),} butin proportion are exceedingly small and. slender, being very little lareer than those of the common mouse—in an, animal seven inches in length of body, and nearly six inches in girth, the fore legs measure less than one-inch and a half to the extremity of the nails; the latter are. black, compressed, sharp, and hooked, as in the squirrel. Habit. According to Mr, J, J. Audubon (to whom Iam indebted for this specimen), this animal never burrows, but con- ceals itself in hollow trees, generally forming a hole in the side, somewhat after the manner of a woodpecker, where they retreat in case of emergency., They.inhabit the cotton fields .exclu- sively ; carry their young on their back; and, with their family thus secured, climb dead trees as nimbly as the squurel, > Inhabit the borders of the Mississippi—the present specimen from Beech woods near Natchez. nit sane On the whole, the present species bears a near resemblance ‘to the Arvicola hortensis, but is sufficiently distinguished by the extreme a pr minuteness of the fore legs and feet, by ‘the colour of the fur, as also in size and. in the tapering form of the body at the root of the tail, the manners of the animal, &c. - —(American Journal of Science.) rigadls w. , * Vid, Fauna Americana, p. 138, & Thid, p. 186, 1826.7 SO New Patents. bhi | 239 Arricie VIII. NEW SCIENTIFIC BOOKS. PREPARING FOR PUBLICATION, -Elements of Chemical Science, in one vol. 8vo. by Dr. E..Turner. Dr. Forbes, of Chichester, is preparing a Translation of the improved edition of Laennec’s Treatise on Disorders of the Chest, with Notes and Commentaries. 89eo8 : : The Tenth Part of the Animal Kingdom, described and arranged in Conformity with its Organization; by the Baron Cuvier, &c.: with additional Descriptions of all the Species hitherto named, of many not before noticed, ‘and ‘other original Matter; by E. Griffith, FLS. and_ others. vt vl &. ee ; eee | Dr. W. J. Hooker is preparing a Third Edition of his Muscologia . Britannica, containing the Mosses of Great Britain and Ireland syste- matically arranged. 0-80-10 1 “rehab -; xBuohd). JUST PUBLISHED. Pee. Researches into the Nature and Treatment of the several Forms of Dropsy. .By Joseph Ayre, MD.» 8vo. 8s. 7 | 21K The Surgery of the Teeth, exhibiting a new Method of treating Diseases of the Teeth and Gums, with Remarks on the present State of Dentist Surgery, and the more prevalent Abuses ,of the Art. By Leonard Koecker, Surgeon Dentist. 8vo, 14s. Sweet’s Hortus Britannicus, Part I. 10s. 6d. 2 OT An Inquiry concerning the disturbed State of the Vital Functions, usually denominated Constitutional Irritation. By B. Travers, FRS. Journal of a, Third Voyage for the Discovery of the North-west Passage. By Capt. W, E. Parry. 4to, With Plates. ; chs ® -~ : ArticLe IX. / oe 8) NEW PATENTS. ..J.-Barron,.Birmingham, brass-founder. and venetian blind-maker, for a combination of machinery for feeding fire with fuel.—July 24. _ W. Johnston, Caroline-street, Bedford-square, jeweller, for improve- ments on ink-holders.—July 24. | W. Robinson, Craven-street, Strand, for a new method of propelling vessels by steam.—July 24. is sit 2 W. Parsons, Dock Yard, Portsmouth, naval architect, for improve- ments in building ships, which are calculated to lessen the dangerous effects of internal or external violence.—July 24. ..W. Davidson, Glasgow, surgeon and druggist, for: processes for bleaching or whitening bees’-wax, myrtle-wax, and animal tallow.— Aug. 1. #92, O11) Sit T, J. Knowlys, Trinity College, Oxford, and W. Duesbury, Bousal, y aioe collar manufacturer, for improvements in tanning.— ug. 1. 240 —C, Mr, Giddy’s Meteorological Journal. (Szer: ARTICLE X., Extracts from the Meteorological Journal ke As the Apartments of the Royal Geological Society of Cornwall, Penzance. By Mr. E. C. Giddy, Curator. . oe S i wf uA A i Boraine lanueman’} h Barometer. | Reorsrs ‘Turns: | pain in iI [80 ee 1826, ————_—__—- 1100 of Winns} REMARKS.) 4 Max. | Min. | Mean, |Max.|Min.} Mean. finches. RLvot siete July 23} 30-00} 30-00|30-000| 66] 58 | 620]. | NE |Clear, '24) 30°02 | 30-02 |30-020| 67°] 56 | 61-5 TONY [CIRM ee cae ' 25) 30-06 |-30-04|30°050] 68 | 59 | 635°} 9 oP NE \Clear, 60 26} 30:08} 30-08}30:080) 72.].58 | 65:0}. “orf NE |Clears io 920i) 27| 30°12| 30°10/30°110] 70 | 58 | 64:0 SE Clear. awilso 28| 30-12| 30-08|30-100} 70 } 56 |. 63-0. Lb: SEs (Cleator cre wg * go} 30-00} 29-98|29-990] 70 | 56 | 63-0] | SE Clear. 30] 29°90] 29°86 |29-880| 72 | 58°] 65:0} ~ | SE |Cleat.: fs 31| 29°82] 29-80|29-810| 76 | 60 | 68-0 SW |Cleare 2 6) Aug. 1] 29-82] 29-78 |29°800| 72 | 60 |, 66°0 |. . NE {Cloudy ; thunder. 2} 29-70| 29°70|29-700] 75 | 62 | 68-5 _.| SW |Cloudy. * 3} 29°73) 29°72/29-725| 70 | 60 | 65-0. "NE |Some showers. 4| 29°76| 29°74|29°750| 70 | 60°} 65:0 |. |. Ny |Showers. 9 5| 29°82). 29°80 /29°810| 68.| 60.| 64:0 | O15 |..N \ |Cloudy.; - 6) 29-96| 29-90/29:980| 713 | 58 | 65°54, | NW: |Clear., .... 7| 30-12} 30°10|30°110| 70 | 58 | 64-0— NW iClear... oer 8} 30-08 | 30:06|30°070} 71 | 58 | 64-5 | ~~ | NW |Clear, 9 29-90! 29°88 |29-890| 70] 58 | 640) © | N|Glear.. — ' 10) 29°86} 29-°80/29°830} 71] 58 |. 645 —| NW |Cloudy.2 J >2 11| 29°80 29-78|29-790| 68°] 60 | 64-0 | 0:08 |, NW. /Showers ; clear iz} 29-90] 29-82|29-860| 68 | 56 | 62:0} | Var. \Clear. 13) 30-00 | 29-98}29-990| 68 | 55 | 61-5 o>) NW. |Clear. 14: 29-68 | 29-60|29-640| 70-|.58 | 64:0} — =| NW |Clear. © 15| 29°78) 29:76/29-770| 74 | 56 | 65:0} — - SW |Clear; rain at night. 16, 29°80} 29-70|29-750| 68 | 56 | 62°0 | 0°05 | SW |Clear. 17} 29-96) 29-90|29-930| 70 | 58] 64-0 SW Clear. 18 30°12} 30-10|30°110} 74 | 56 | 65:0 S |Clear; fair. 19 30-06| 30-00}30-030| 72.| 58 | 650 |. S |Clear 20, 29°90} 29:88}29-890| 70 | 58°|) 64:01 . W Clear. 21| 29-88| 29:87 |29°875| 10 | 57 | 63-5 N_ |Clear. 22, 29-80) 29°78 |29-790| 72 | 56>), 64°0;}5—- | W_ |Clondy | 30-12} 29-60 |29-910) 76 | 55 | 65-0 } 0-280) NW. RESULTS. ‘adelaide Barometer, mean height ...e.cesecessessereees 29910 | 5 5.4, . Register Thermometer, ditto .....eeeederesse¢e GFO° 9) 5 Rain, No. 1, 0:280, No.2, 0°610, sty rsyert Prevailing wind, NW. (4.3 No. 1. This rain guage is fixed on the top of ‘the Museum of the Royal Geological Society of Cornwall, 45 feet above the ground, and 143 above the level of the sea. No. 2. Close to the ground, 90 feet above the level of the sea. . Piiiritnce; ‘Arig. 28,1626. 18 «| : | EDWARD ©: GIDDY... ANNALS OF PHILOSOPHY. OCTOBER, 1896. ARTICLE I. Biographical Notice of Joseph-Louis Proust, Member of the Institute, of the Legion of Honour, of the Royal Academy of Medicine, and Professor of Pharmacy.* FRaNcE has recently lost one of the most illustrious of her learned men. Joseph-Louis Proust died at Angers, his native city, on the 5th of July last. . This loss, which affects all who are interested in the progress of science, will be most severely felt. by the professors of pharmacy, who have been deprived or ‘one of their most honoured members ;—a man whose name will be associated with those of Scheele and. Rouelle ;. with all the most celebrated discoveries in pharmacy; and in whom an. elevated genius was accompanied by a simplicity of manners __ and a modesty that heightened its splendour. terest, _ Joseph-Louis Proust was born at Angers, in 1755, in which city his father was an apothecary, and from his youth he was intended for the same profession. Having completed the early part of his education at home, he came to Paris, to work under the direction of M. Clerambourg, a respectable apothecary. He was there remarked for the zeal with which he studied chemistry and the practice of his art, and he was not long in reaping the reward of his labours. ) _. The office of Chief Apothecary at the Hospital de la Salpé- triére becoming vacant, it was left open to competition; young Proust did not become a candidate, but some of his friends, knowing his modesty and merit, placed his name in the list. This competition was attended with brilliant success, and - formed the commencement of his. reputation ; he obtained the office with every vote in_ his favour, which procured him an honourable subsistence, and the means of readily prosecu ing the study of chemistry, for which he had an irresistible incli- nation. : 7 - * From the Journal de Pharmacie, for July, 1826. New Series, vou, Xit. R : * 242 Biographical Sketeh of M. Proust. [Ocr. From the lectures and conversations of Rouelle, he imbibed his decided taste for this science, and also, perhaps, that original and acute mode of \thinkihg, which was so eminently characteristic of his master. Rouelle was a competent judge of talent; he assisted the young chemist with his advice, | honoured him with his friendship, and facilitated the commence- ment of that ¢areer which he Continued withso much success. During the time that he retairied ‘his situation at the Salpé- triére, Proust wrote and published several notices and memoirs, among which may be metitioned his Researches on Urine, his Essay on Phosphorie Acid, &@ Memoir,on Pyrophori without Alum, Experiments on the rapid Combustion of Essential Oils by Nitric hei &c. He discussed the ie which had been previously broached on the subjects,of which he treated, and he early evinced that independence of mind which afterwards appeared in his scientific researches... wi) oy hoe . Proust was known at this period not, only by the works which he published, but also: by, teaching chemistry with, great success in. the Musée du Palais Royal, and also in a private establish- ‘juent founded by the tinfortunate Pilatre de Rosier. He accom- ari this pliilosopher ii his ‘first aérostati¢ ascent, which téok place at Versailles on the 23d of June, 1784, in the presence of the Court, and of the King of Sweden, who witnessed this exhibition for the first time. The balloon rose at first with ‘some difficulty, and the rapid oscillations caused by the wind occasioned a momentary apprehension for the safety of the two atronauts; but being soon freed from the shackles which detained it on earth, it tose majéstically into the lofty regions of the atmosphere, and speedily allayed the fears of the multitude — for the safety of the intrepid navigators. | BO _. This aétial voyage; the longest which had tillthen been made, ‘and the acwoulit OF Whigh is extréinely curious, was crownéd with complete success; the balloon descended without any ‘damage, in an houi and séveli ihinutes, at thirteen leagues from the place of ascent. Proust peremiptorily refused to have any thing to do with the second ascent, the danger of which he foresaw.* It was not his fault that the unfortunate Pilatre did not escape the vd eine acéidefit of which he was the victim, and which too well justified the melancholy forebodings of the chemist. | ane The Spanish government, observing the progtess which the physical sciences were then making in France, aiid foreseeing the resources which they might’ afford to the industry of a people, offered Proust a professorship in the School of Artillery ‘ * This second ascent was made by combining thé process of Montgolfier with that of Charles ; there were two balloons, the upper one was filled with hydrogen gas, and the lower one with air exparidéd by heat; that which Proust had foreseen occurred, the hydrogen gas took fire, and Pilatre de Rosier was precipitated from the air, with acom- panion, who, wishing to participate in his glory, shared his fate. % 1826.] Biographical Sketch of M. Proust. 248 at Seyovia: he set out for Spain, and quickly realized the high hopes which his reputation had inspired. He proposed or ‘perfected a great number of processes interesting to the industry of that country, and on several occasions he received the most flattering proofs of the satisfaction of its Sovereign. This monarch determined to found a central school of chemistry at Madiid, and’ Proust was there appointed Professor of this science; he was treated at this place with great attention and respect atid the whole establishment was endowed with a truly royal magnificence. Almost all the utensils; even those most borg sina employed, were of platina, which the king presented It was in this laboratory and in that at Segovia that his principal Operations were performed, among which a great number may be mentioned, the chief object of which was thedirect benefit of the country. It is to him that we owe the first analysis of the native phosphate of lime of Lograsan, in Estremadura. He also made some experiments upon saltpetre and sulphate of magnesia, both of which occur native in Spain. He published a very minute account of the essential oils of Murcia, and showed that caiiphor might be advantageously procured from them. He ‘also made many experiments to determine the quantities of charcoal which are yielded by different kinds of wood, and upon that which is procured from the coal and peat of Spain. We aré indebted to him for an analysis of the native iron of Pert, in which he found nickel, atid also for ‘a great number of experiments upon several American minerals, and particularly upon the ore of platina. He also published a work on the. means of bettering the sustenance of the soldier; these means are chiefly derived from the nutritive property of gelatine pro- cured from bones. Papin had before him proposed to extract it, by subjecting the bones to a very strong heat in the digester which bears his name. Proust endeavoured to revive the project of Papin, bit he substituted a more ready method of extraction. =~ | : ae This work, which is less remarkable in a scientific point of view than with réspect to the extremely important question of which it treats, is well calculated to give an idea of the lively and original maiiier of its author, and especially of the zeal with which he endeavoured to diminish the privations of the lower classes of Society. - ’ ouet nae with thé same intention of offering to the poor a new and nourishing substancé, which was both abundant and cheap, that he afterwards published a niemoir on the lichen islandicus. In this, as well as the preceding memoir, and indeed as in almost all his works, there appear the same deep feeling of humanity and the saiie active zeal for the benefit of his race, which incessantly éxcited him to discover the means of ameliorating their condi- ie RQ 244 Biographical Sketch of M. Proust. [Ocr. tion, by teaching them to take advantage of the resources with which Lenevdlent nature has so profusely surrounded them, To him, true science was, as he says in this memoir, “ that which teaches us to obtain from the productions with which'the ‘Creator has abundantly supplied the world we. inhabit ‘not only the best, methods of increasing the means of subsist- ence, but of enriching medicine, domestic economy, and the arts.” : : . He also wrote several memoirs on the sugar of grapes, and on | the methods of preparing it; and in these he still kept in view the supplying of the poorer classes with an agreeable and whole- some food, of which they were particularly destitute at the time at which he undertook the investigation. ae e Besides the labours which we have mentioned, Proust pub- lished ‘a great. number of memoirs, which enriched science, and ranked their author among the first chemists of the age. | Favoured by fortune, honoured with the esteem of the public and the protection of theSovereign, possessing extremely curious collections of the most remarkable arid precious productions of both ‘the Indies, which would have supplied an inexhaustible source for his researches, it remained only for Proust to enjoy the happiness he had himself created; when in one day all his hopes vanished. He was in France on leave of absence, when the chances of war brought the French. to Madrid, and ruin ‘on his establishment—a ruin which was so complete that his ‘personal loss may without exaggeration be estimated at more than half a million of francs. Reduced to a state bordering upon indigence, -he bore this reverse with stoical courage, and if some expressions of regret: escaped him, they were not for his fortune, but for the collection of chemical and mineral substances. which he had. formed with so much care, Who would not share his regret, when, in speaking in one of his memoirs of some minerals which he had intended to analyze, ‘but. which want had forced him to sell, he exclaims, with affect- ing simplicity, “Oh! destiny of human affairs, instead of analyzing these minerals, it is necessary to’deliver them to one of those persons to whom we say, [ac ut dapides istt panes jiant.” f Napoleon wishing to encourage the preparation of sugar of grapes, engaged Proust to establish a manufactory for it at the expence of government, and he decreed him a gratuity of 100,000 rancs. Proust refused it, his health and age not’ permitting him to fulfil the duties attached to the imperial liberality. He retired to Craon (Mayenne), where he lived on his moderate patrimony. ; Although he did not reside at Paris, he was nevertheless, by ' particular favour, nominated Member of the Academy of Sciences, on the 12th of Feb. 1816, inthe place of M, Guyton de> —_ 1826.] - Biographical Sketch of M. Proust. — 245° Morveau: this favour-was as flattering to him as it was honour- able to those who granted it: ‘The advantage belonging to the title of Academician, which he enjoyed from this period, and a. pension of 1000 francs, which he derived from the liberality of the late king, Louis X VIII. contributed to render his existence more happy towards the end of his life. oP: ¢ After his nomination to the Academy of Sciences, Proust returned to Angers, his native city; he there wrote several memoirs, some of which were addressed to the Institute; he also sent to the Academy of Medicine some researches into one of the causes which occasion the formation of calcul. Lastly, he was occupied in an important work upon urine, when death snatched him from science ; it is, however, to be hoped, that this work, which was considerably advanced, will not be entirely lost, and that the first part of it will be published. As we can only give ‘a concise account of the scientific claims of Proust, we shall not give the titles of all the memoirs which he published in most of the records of science, especially in the Journal de Physique, from 1771 to the present period. We shall name only the principal : we first mention his Memoirs on Prussian Blue, in which he shows that the colour of this sub- stance depends upon the degree of oxidation of the iron, that this oxidation cannot exist in all proportions, but that it stops at. two fixed points, and that all the shades observed in prussian blue are derived from a mixture of the two prussiates of iron ; he states a great number of the properties of this singular product, which has since exercised the sagacity of the most distinguished chemists, and upon the nature of which they are not yet agreed. We will also mention his work upon tin, which is avery remarkable memoir, replete with new and curious facts, and in which he decidedly proves, that tin, as well as iron,.is susceptible of only two degrees of oxidation; he very minutely describes the two chlorides of tin; he explains the deoxidizing action of the protochloride upon indigo, the salts of peroxide of iron and of copper; he first showed the existence of a chloride of copper differing from the green chloride, and of a protoxide of the same metal, which was not suspected before his labours. -His researches on the oxides of cobalt and nickel are of great importance, and so also are those upon antimony, arsenic, mer- eury, silver, and gold, upon the metallic sulphurets and upon gunpowder. _. We observe in reading these memoirs, that independently of the peculiar merit of each, they are all intended to prove that no combinations of bodies with each other occur in indefinite proportions, but that they are subject to invariable and fixed — proportions ; to that pondus nature, as he himself says, * which characterizes all the true compounds of. art and of nature.” This opinion of Proust respecting definite proportions, which 246 Messrs. Babbage and Herschel on. the [Ocr. was his favourite subject, and which is found in every page of his memoirs, was not, however, admitted by all the chemists of, the day. A chemist, whose recent loss the sciences still lament, the learned author of the Statique Chimique, long disputed an, OpiHIOR which ill accorded with his ingenious theory of chemical, affinities ; and he roi with so much sagacity, that he left, the question long undecided. andi l The chemists, however, who afterwards occupied themselves. with the same subject, fully confirmed the opinion of Proust, which has been greatly extended by the more exact knowledge of the composition of a great nie) of bodies that has been. — acquired, It is, in fact, one of the best demonstrated truths of modern science, and it forms the basis of the atomic theory.» We are undoubtedly far from having enumerated all the claims to renown which belong to M, Proust; it would be necessary to dedicate more room to it than can be allowed to a mere notice. A Member of the Academy of Sciences, and of the Aca- demy of Medicine, he will find in these two societies, philoso- phers who are more eloquent and more worthy than we to pay that homage to his genius which is its due; but it particularly, belongs to the editors of a journal dedicated to the professors of pharmacy, to announce the loss which they have suffered, and. to strew the first flowers on the grave of so illustrious a philoso~ pher and so good a man, sy. iho wd an - Articie IT, Abstracts of Papers in the Philosophical Transactions for 1825, on the peculiar Magnetic Effect induced in Iron, and on the Magnetism manifested in other Metals, &c. during the Act of Rotation. By Messrs. Barlow, Christie, Babbage, and Herschel. 3 | (Concluded from p. 192.) Account of the Repetition of M. Arago’s Experiments on the Magnetism manifested by various Substances during the Act q Rotation. By C. Babbage, Esq. FRS. and J. F. W, Herschel, . Esq. Sec. RS. (concluded.) When we come to reason on the above facts, much caution is doubtless necessary to avoid over-hasty generalization. Whoever has considered the progress of our knowledge respecting the magnetic virtue, which, first supposed to belong only:to iron and its compounds, was at length reluctantly conceded to nickel and cobalt, though in a much weaker degree—then mperted to belong to titanium, and now extended, apparently with an extraordinary range of degrees of intensity to all the metals—-will hardly be inclined to stop: short here, but will 1826.) Magnetism of Metals, &c..arising from their Rotation. 247: readily admit, at least, the probability, of all bodies in nature participating in it more, or less. Yet if the electro-dynamical theory of magnetism be well founded, it.is difficult to conceive how ‘that, internal, circulation: of electricity, which has. been, regarded. as necessary for the production of magnetism, can. be excited or maintained in, non-conducting bedies,,. Without pretending to draw a line, however, in what is perhaps. at last only.ai question of degree, one thing is certain, that all the, unequivocal cases of magnetic action observed by us, lie among the best,\conductors) of electricity.. Another feature, no less striking, is the extreme feebleness of this species of action compared, with that which takes place in cases of sensible attraction and:polarity. This will appear more evidently, if we consider, the: mode of ‘action which probably obtains in these experiments, and the mechanism, if we may so express it, by which the effects of such almost infinitesimal forces are rendered pdreeptible:m:theme yiifo)%0 gone hind Gongs o% HAI Yo The »rationale. of these phenomena, as well as of those observed by Mr. Barlow in the rotation of iron, which form only a particular case (though certainly the most prominent of any) of the class in question, seems to depend on a principle which, whether it has or has not been before entertained or distinctly stated in words, it may be as well, once for all, to assume here as a postulatum, viz. that in the induction of magnetism, time enters as an essential element, and that no finite degree of magnetic polarity can be communicated to, or taken from, any body what- even susceptible of magnetism, in an instant. . This principle will, if we mistake not, he found to afford at least a plausible explanation of most, if not all the phenomena, above described, without the necessity of calling in any addi- tional hypothesis; or new doctrine in magnetism. For the other principle we shall have occasion to employ, that magnetic bodies differ exceedingly, both in susceptibility of this quality and in the degree of the pertinacity with which they retain it, (which may be called their retentzve power,) is not an hypothesis, but an acknowledged fact. It is only in the mode of its extension to new cases of magnetics that we can be led into any fallacies. Whether these two qualities (susceptibility and retentive power) be; or be not) mutually dependent, this is not the place to inquire. ; Probably they are not so, at least directly: and the new facts almost convert this probability into certainty; at all events, at: present, we shall, for greater generality, suppose them independent. : ! kota | | mon » Conceive :now:a plate of) any, thickness, and. of indefinite superficial extent, of a metal or other magnetic, whose retentive power is;very small. If either pole (suppose the north) of a magnet:be brought vertically over a point in its surface, it) will there» produce: a pole of the contrary name. in. the -plate, the | 248... Messrs... Babbage and Herschel on the... [Oor. maximuny of polarity being immediately under-the magnet. Now let the, engi be, moved. horizontally, along the surface, pre- serving the same, distance. from,.it. The pointsiover:which in succession. it becomes. vertical, not. Stet receiving jall the magnetism of which they are susceptible, will not-have teached: their maximum. of polarity at, the precise ;momentyof, nearest appulse, but will continue. to,receive fresh/accessions, during the whole of ‘that certain small portion of time when the distance (being at or near its minimum). undergoes no change, or only a certain very minute one. .In like manner, the points which have attained their maximum of polarity, being left behind, bythe magnet, will by degrees lose their magnetism ;, but: the loss: not being sudden, they will continue, near their, maximum ‘for a certain finite time, during the whole of;which the magnet: conti- nues receding from them, and leaving.them. further and further behind. Thus from both causes, there will be always in arrear of the magnet a space both more extensive and more strongly impregnated with the opposite polarity, than in advance of it;. and as the magnet moves forward, the point of actual maximum (or the pole) of the plate, instead of keeping pace with it, and: being a i recisely, under it, will lag behind.|; There will) thus arise an oblique, action between the pole of the magnetand the opposite pole of the plate so lagging behind ‘it; and) were the plate free to move in its ewn plane, the resolved \portion: of: this action parallel,to its surface, would continually urge. it im the direction of the magnet’s motion... Wye, FL FD Ig ASweN But besides the attracting pole of the opposite name. (south) produced by the (north) pole of the magnet at the spot imme- diately under it, there will. also ‘be developed: a corresponding. repulsion, or. north polarity in, the, plate., This, -however, »will not, like the attractive, be concentrated nearly in.one spot immediately below the magnet, but must.of necessity be diffused round it in a much less intense and’ more uniform state through- _ out the more distant parts of the mass, and; may be, conceived. as arranged in spherical or other concave,strata about the point vertically under the magnet as acentre.. Now when the magnet by its motion, is carried out, of the axis of these, strata, it: is obvious that the resultant force of each of them will be less and less oblique to the surface as its radius is greater. |, The general resultant, therefore, of all the repulsive forces exerted through. : out the whole extent of the plate is necessarily. less oblique to the surface than that of the attractive ones,. whose influence, from this cause alone, must, therefore, preponderate,, and must. necessarily produce a dragging or oblique action, such as above - described. This force, however minute, acting constantly, must: at length produce a finite and sensible velocity, provided: the, whole mass of the plate to be set in motion be) finite, and, the: force of the magnet sufficient to overcome friction, resistange, &c.’ 1826.] Magnetism of Metals, 8c. arising from their Rotation. 249. vVice versa; if the plate be drawn along in its ‘own plane, and the:magnet'be free to: move'in a horizontal dire¢tion, the former oughtto drag the latter along ‘in the same direction with a velo- city continually ‘accelerating, till -they’ move ‘on’ together with equabvelocitiesi® St aa hipaienah 3 :Ttase manifest ‘that, ceteris paribus, the greater the relative velocity; the ‘more will the pole developed in the plate lag behind: the magnet, ‘or the magnet (in the reverse case) behind theypole.) The more oblique, therefore, will be the action, and the greaterthe*resolved part of the force, and the velocity pro- duced by it dato tempore. The same effect must also be produced by amrincrease’‘in the‘absolute force, or lifting power of the’ magnet 5'so'that in such ‘experiments there is an advantage in’ using large magnets which have great lifting powers, over small ones' with mtense' directive forces, and this is perfectly conso- nant to experience. soli . /Hitherto:we have only considered the case of rectilinear motion. If we regard the magnetism of the plate as very tran- sient;‘and the velocity moderate, the whole space occupied by the»magnetized portion of the plate will still be small, and confined ‘to the immediate neighbourhood of the point vertically under the magnet. Ifthe motion of the latter change its, direc- tion, 'the:momentary pull communicated to the plate will always be inthe direction of a tangent to the curve described. If, . therefore,’ it describe a circle, it will tend at every instant to impress a gyratory motion on the plate about a centre vertically under the centre of its own motion, and vice versd, if the plate be made'to: revolve about a centre, it will tend to drag the magnet round with a’ continually accelerated motion, provided its rectilinear recess from the centre of motion (or its centrifugal - force) be prevented’ by a proper mechanism. The former is the case of a'disc of copper suspended by its centre, and set in rota~ tion by'a’magnet ‘revolving beneath it. The latter is that of a'compass-needle, or of our neutralised system of vertical mag- nets suspended over a revolving disc of copper. A very pretty illustration of the direction of these forces is obtamed by suspending a circular disc of zinc or. copper from the end of a’. counterbalanced arm, which is itself suspended by its middle, thus constituting a kind of double balance of torsion. If the length of the arm be so adjusted, that the circumference of the disc shall bean exterior tangent to the circle described by the oles of a revolving magnet, the whole disc will be swept round in an orbit concentric with the motion of the magnet, white it at. the same time acquires a rotatory motion on its own centre in. the contrary sense. The centrifugal force is here overcome by the arm and ‘the:weight of the disc, and the velocity goes on accelerating till the increase of resistance puts a stop to further accessions.) 605 4 , Oi adi ie sis al ba 250 Messrs, Babbage.and Herschel on the... (Ocv. In Mr, Barlow’s experiments, the earth is our inducing mag- nét ; its two poles both act, on every particle of the revolving: shell employed in that gentleman’s experiments, and their action, when complete produces. two poles, a north and a south, at) opposite extremities of the diameter parallel to the dips; This» is the case when the shell is at rest. Let it now be set in motion about any. axis, anyhow inclined to the dip.. Ifthe communica~ tion and loss of magnetism were instantaneous, the places, of the poles (i, e. the points of maximum polarity) would be unaf-) fected by the rotation ; but as that is not the case, these points, in virtue. of the principles already stated, will shift their places, and decline from the direction of the dip in the same direction, as the shell’s motion, that is to say, inthe direction of a tangent: to a small circle, whose axis is the axis of rotation, and whose: circumference passes through the extremities of the diameter, parallel to the dip. The extent of this declination will. depend: on the velocity of rotation and the diameter of this small circle, and will be proportional to both, that is, to the velocity of rota-: tion multiplied into the sine of the angle made: by the axis of: rotation with the ditection. of the dip, It will, therefore, be: a: maximum when the axis of rotation is perpendicular’ to the, magnetic meridian, and vanish when the shell is made to revolve: on an axis parallel to the line of dip. . These consequences, are) erfectly consonant to the results obtained by Mr. Barlow im i paper; and, in fact, the general result announced by him in p- 449 of this volume, comes to the very same thing as above. stated ; for it is obvious, that the. new axis of polarization there, — spoken of, acting in combination with the original,. or, as we may call it, the primary axis developed.in the quiescent state of the shell, will exert a compound force on the needle, such.as_ would be exerted by a, single equivalent axis situated inter-. mediately between them, but much nearer to the more intense than to the more feeble one... The position of this equivalent: axis will necessarily be in the great circle passing through the: two component ones. Now the small cirele described by the: point which was first the pole of the stronger or primary axis. about the axis of rotation is a tangent to this great. circle, and the equivalent axis (being but little removed: from the primary one, by reason of the small intensity of the other), will, there-: fore, have its pole situate indifferently in either circle. Or! conversely, the single axis produced in our view of the subject, being resolved into two; one of which is that corresponding to the quiescent state of the shell, and the other 90° removed from. it in the same place, this latter will be identical with Mr. Bar-) low’s secondary axis, ..) it pod gre HOs 341) In what has been said, the velocity of rotation has been sup-) posed commensurate to the velocity with which magnetism: is: propagated through the iron of the shell. But if we-conceive: 1826.] Magnetism of Metals, &:c.arising from their Rotation. 251 in this, orin the general case; either the retentive power of the shell, disc, or lamina, great, or the velocity of motion excessive, it may bevinstructive to consider, the modifications thus intro- duced:into the effect. It is evident that: the induced pole. will lag farther and farther: behind the magnet in proportion as either of these conditions obtains. In the case of rectilinear, motion, this will, up to a’certain point, increase the oblique. action, and the dragging effect will be strengthened ; but if the: velocity be excessive, or the retentive force considerable, as in, steel, the pole may lag so far behind as to carry it altogether, out of the sphere of the magnet’s attraction ; and the magnetized _ portion, remaining within its limits, may have not had. time’ enough to acquire a high degree of polarity.. From both causes: the drag (the expression, though uncouth, is convenient) should; be weakened. In the case of circular motion this effect may go, so far, that.a complete circumference shall have been described before the polarity of any one: point shall have been either com-. pletely induced, or completely destroyed. In this case the effect observed will be a general weakening of the total. polarity of the disc or sphere; and (supposing the latter of iron, ,or soft. steel) a directive virtue on a small compass-needle placed near _ it, not probably towards any particular place, but to a resultant. imaginary point depending on the situation of the compass, the, dip, and the axis of: rotation, by laws:not very easy to assign. This will explain-some expressions quoted by Mr. Barlow.from his correspondence with one of the authors of this, paper, which’ pices appear otherwise to militate against the general view here taken. | : gb ob This diminution of the total effect by a more general distribu- tion of the magnetism, was imitated by sticking a great number of needles vertically through a light cork circle, all being strongly magnetized, and having their north poles downwards, so as to form a circle, or, as it were, a coronet of magnets... This appa- ratus suspended centrally over a revolving copper disc, was not sensibly set in rotation. In this case, when at rest, the south polarity induced in the plate would be.disposed in spots accu- mulated under each needle; but these spots, elongated and blended by the effect of rotation, must produce a nearly uniform. circle of south polarity, whose equal and contrary actions on all the needles would keep up the equilibrium, and prevent the coronet from acquiring a tendency either way. / One consequence of this reasoning, which deserves trial, is this—that if the axis of rotation of an iron shell be situated mn. the direction of the dip, the spots occupied by its poles will not change their places by rotation, and consequently no deviation of the compass ought to take place from that cause. The expe- riment, however, is very delicate; and care must be taken to remove any magnetized bodies whose influence might induce * 252. Messrs. Babbage and Herschel, and» [Ocr. subordinate poles in the shell, whose places would shift by rotation. The compass, therefore, in this case cannot be neu- tralized by a magnet ;* but we must have recourse to some neutral system, such as that described in the foregoing pages, in its place, or it may be left unneutralized. It ought too to be so small, or so remote, as not to produce induced polarity in the shell, which would react on itself when the sphere is.set in motion, and destroy the success of the experiment. ~ The effect of a solution of continuity in the revolving bodies comes next'to be considered. It is difficult ; but the difficulty is not a consequence of our principles of explanation, but of our ignorance of the very complicated laws which regulate the dis- tribution and communication of magnetism in bodies of irregular figure. So far, however, as the operation of the general principle ean be traced, its results are consonant to observation. In the first place, it is obvious that where one or more slits are cut in a metallic plate, over which the pole of a magnet is revolving, that immediate and free communication between particle and particle, on which probably the rapid, and certainly the intense developement of magnetism depends, is destroyed. The induced “omer (by which we mean now the whole of that space in which sensible magnetism is developed, and which is, of course, a spot of sensible, and probably considerable magni- tude—of a figure more or less elongated according to the velo- city of the rotion)—instead of travelling regularly round, retain- ing a constant magnetism and force, will now be in a perpetual state of change. Instead of being carried uniformly across the slit, it will die away in intensity, and shrink into a point in dimension on the hinder side, and be again renewed on the side an advance, but at first notin its full intensity ; so that it is not merely the diminution of surface arising from the abstraction of ‘apart of the metal, but a much more considerable defalcation of magnetic force which takes place on either side of the slit, that operates.. Now this operation is always to weaken the drag between the magnet and the disc, and no reason, a priori, can be assigned why this effect should not take place to any extent. The validity of this reasoning is shown by taking the extreme case in which the substance acted on is in the state of powder. Each particle of this becomes necessarily a feeble magnet, and its north and south poles, being at the same distance (almost precisely) from the pole of the magnet, counteract each other’s action. ‘The extreme feebleness of their magnetism prevents the particles from affecting each other by induction across the intervals which-separate them; so that each acts as an indivi- dual, and destroys in great measure its own effect. ‘The moment, * In Mr. Barlow’s experiments, the large and powerful bar-magnets used to neutral. Ds one aah action pn the compass-needle, cannot be without some disturbing influence 1826.] Mr, Christie on the Magnetism,arising from Rotation. :253 however, a. metallic, i.e. a -magnetic contact is established between them, their mutual induction acts, and the result isa general developement of one polarity in the region adjacent to the magnet; and of the other, feebler and more diffused, in the _parts'of the mass remote from it. This is probably: the rationale of the restoration of virtue which takes place when a cut. disc is soldered up. And it is not difficult to conceive that a.weak magnetism may be thus very faithfully transmitted through ‘substances, such as bismuth and lead, whose direct action, 1s very small, because, as we have seen, the intensity of their direct action depends, for one of its causes, on the retentive power of the sebetanens which is out of question in the indi- rect mode of action here considered. In fact, if the retentive power of the solder were reduced to nothing, i. e. if it gained and lost magnétism instantaneously, it would. still act as. a: conductor, and probably the better for this quality; so that the communication between opposite sides of a slit, or contigu- ous portions of two adjacent particles of a powder, would still be kept up by it, provided it were susceptible of magnetism at all. ‘The observed. and very striking fact then of the powerful action of bismuth as a conductor, while its action as a magnet. is so extremely feeble, is in itself a strong argument for the inde- pendence of these two qualities, which we have designated by the - expressions—susceptibility, and retentive power, and may possibly be made the foundation of a mode of distinguishing and measur- ing their degrees in different substances. ) | ! ime On the Magnetism developed in Copper and other Substances during Rotation.. Ina Letter from Samuel Hunter Christie, Esq. MA. &c. to J. F. W. Herschel, Esq. Sec. RS, » After having made experiments with a thin copper. disk suspended over a horse-shoe magnet, similar to those which I witnessed at Mr. Babbage’s, I made the following. : A disc of drawing paper was suspended by the finest: brass wire (No. 37) over) the horse-shoe magnet, with a paper screen between. A rapid rotation of the magnet (20 to 30 times per second) caused no rotation in the paper, but it occasionally dipped on the sides, as if attracted by the screen, which-might be the effect of electricity excited in the screen by. the friction of the air beneath it. | Adisc of glass was similarly suspended over the magnet: no effect produced by: the rotation. A disc of mica was similarly suspended : no effect. The horse-shoe magnet was replaced by two bar-magnets, each 7:5 inches long, and weighing 3 oz. 16 dwt. each, placed 254 °° MA, Christie on'the Magnetism developedin [Oor. horizontally parallel to éach other, and having their polés of the same name contiguous. ' These produced quick rotation in a heavy disc of copper six inches in diameter, and suspended by a wire; No. 20, ¢ HU oy A bar-imagnet, fotir inches long, aiid having ‘both its ends south poles, was made to revolve rapidly under a copper disc. The disc revolved in the same direction as the magnets. | The two bat-magnets before-mentioned were adjusted to the axis of rotation, so that their upper ends were at the distance of five inches from each other, and their lower ends 1°8 iiich apart. They were first made to revolve rapidly under the copper disc with poles of the same name nearest to the disc, and then with poles of a contrary name: the times in which the several rotations of the dise took’ place were as nearly as possible the Same in the two cases. : agers ae ogee Be ‘In the first three, I could only rémark the time to the nearest second, having no assistance. Should the times agree precisély, which I have very little doubt they would be found to do, the result would, I think, be singular. It would show that the inagnetismh ih the disc is instantaneous! Rib by one pole of the magnét, and as instantaneously dastrogé , anid a contrary magnetism developed by the contrary pole; or rather it would indicate, that the time during which the disk retained’ the induced magnetism was less than the time of half a revoltition of the magnet. — | | bo peor. The same two bar-magnets were laid horizontally by the side of each other, four-tenths of an inch a part. They were first made to revolve rapidly under the ‘disc with their poles of the same name adjacent, and then with those of a contrary name adjacent. aurea. t ky : Wh ght ut) _ Brom, these it appears that the effect was but little diminished ~ by Oda poles of a contrary name so close to each other. _ The adjacent poles being of the same name, they were con- nected by a piece of soft iron; one-eighth of an inch thick, and half'an inch wide. After 44 revolutions of the disk (screw), thé torsion of the wire was equal to the force of the magnets, and the saine was the case at 4% revolutions (unsetew). So that although the effects were greatly diminished by connecting the poles, they were by no means destroyed. . _ The magnets were now placed over each other, first with poles of a contrary name, atid then with those of the saitie name contiguous ; so that although the upper magnet was nearer to the dise by its own thickness than in the fourth experiment, the effect when poles of contrary tlanie were Conti@uous was not half what it was when they were connécted by the iron. A thick copper plate, eight inches in diameter, and otie inch thick, was placéd on thé axis of tapid rotation, its plane hori- zontal. A thin copper dise, four inches diaieter, and weighing 1826;] Cobper and other Substances during Rotation. 255. 23'S dwts. was very delicately suspended over it by a fine brass wire (No. 37), with a paper seréen ‘between the plate and the ‘disc.’ The distance between the surfaces of the plate and disc five-tenths of an inch, The plate being put in rapid rotation, no sensible effect was produced on the disc. ! A bat magnet. was placed.on.the screen under the disc: still no effect produced by the rotation. | es A light needle; weight 42°5 grains, six inches long, on a pivot in a compass-box, being placed over the plate, the. rotation - eaused a deviation of 20°; but when a heavy needle, weighing -197 grains, and of the ‘same length, was similarly placéd over the plate, it immediately revolved rapidly with the platé. | | A bar-magnet, weighing 3 oz. 15 dwts. 19 grs. suspended by a wire, No, 20, revolved rapidly with the plate. | A horse-shoe magnet, weighing nearly a pound, and suspended by the same wire, revolved with the'disc. The following experiments were made with the view of ascer- taining Whether the effects increased nearly according to any power of the decrease of the distance, _ i A strong needle, six inches in length, weighing 197 grains, and vibrating 22 times in a minute, delicately suspended on an agate within a rim accurately graduated, was placed with its centre exactly over that of the copper-plate, and being accurately adjusted, so that the distance between the centre. of the copper _ and that of the needle was such as I required for the observa~ tion, the copper Was made to revolve rapidly (always ‘as nearly as possible 12 times per second), and when the needle bécaiie ‘stationary, the direction of its south end (being that most con venient for observation) was noted. This was done with the ‘copper revolving in both directions, “ screw” and “ tnserew.” ‘The direction of the south end of the needle was also observed before the rotation. | | Distaniee }4-0 in. | $5 in| 80nd | 8-5 in. 240 in. | Screw. ..|° 46’ W]|3° 20! W\6° 20/ W|L4°. 30/W\29° 40’ Wy Direction of southend Unserew.|1 32 E/3 08 E|6 00 E|I3 50 E/29 00 E, of the needle: Mean...11 39° |3 14 [6 10 {14 10. [39 20 On diminishing the distance to 1*5 inch, the needle revolved with the plate, and very shortly so rapidly, that it had the appearance of an entire circle. | After this I replaced the néedle by others which were lighter, letting every thine élse remain the same, that is, the distance still 1°5 inch. | i Needle weighing 42°5 grs.' Needle weighing 25-5 grains. Gh PO FS SOW © Bt S21 6° “30CW Brn WBere We YET TSC a ae ee es eo ages (i should mention that the needles were not at all neutralized). 266 = Mr.Christie,on. the, Magnetism developed in |[Qer. _ From, the, latter observations, it is, evident that , the’. nthe produced de> ends upon the intensity of the magnetism in the needle mapregont and. this, |, think, proves clearly’ that effect arises from the magnetism induced in the copper, from e needle itself, wo SpROS Ww BSboutad on if we suppose the tang. of the deviation to vary as amas then § and 6’ being two deviations at the distances d and d’, we. shail log. tan. ’ — log. tan. 6 Mae hie ¢ ae log. d — log. de *, cotasd.! order & Beeno Computing » from this, by a comparison of every two obser- vations we have the following values of 2: (ised. He haat fie have n = ae t 504 4 '9 OR ae 4 6 2 3:93 gal ii® oily aor | 23 388 | 220 1.8 & eae ( beBtiBe albae 4:29 | ¢ 8 351 1 °ES 4:20 | 2 si Be 4°45 o “64 10 £38 31 23 | EL san (ed 48 @ B)) 359 | 6 278) | Bionic Mean 4°361- > Mean 3:605- = ; If we suppose that the poles of the needle are ai A by forces in the direction of the motion of the copper, which being con- stant in the copper, would affect the needle reciprocally as the square of the distance; then these forces in the copper being derived from the needle itself, we must suppose that their inten- sity will vary also reciprocally as the ical of the distance ; so that the force on the needle arising from this mutual action, would vary reciprocally as the fourth power of the distance. Taking the mean between the mean values of n above, when the distance is measured from the centre of the copper and from its- surface, would give the value of m for an intermediate point 3°983, which is as near to 4, supposing that such ought to be the value, as we could expect the observations to give. The next experiments which I made were with the view of determining the law of. force as regards the distance, when magnets act upon a copper disc. For this purpose I made use of the suspending wire as a balance of torsion. The results which I have obtained in this manner give a much less rapid diminution of the force, as the distance increases, than appears to take place. when a thick copper-plate acts upon a small magnet, as in the former experiments, which agrees. with what you have mentioned as following from your results, The results obtained in the former case appear to indicate, that every ? 1826.] Copper and other Substances during Rotation. 257 particle‘in the’ copper urges the needlé from thé ‘magneti¢ meri- Poeryse ; i. 3 fy ;T} Tani ' of ML, AOR ott mel vel. of particle exh dian. with a force varying as (distance?! ich JasH pro ; from thé hagrietism in the needle developing the magnetism in the particles of copper, so that its intensity would vary as ae Oe i| rans Fae aig ap oa hy needle with a force varying as which law. would arise ,.and this magnetism again acting on the poles of the isn Supposing this to be the case, if x is,the distance of a lamina of copper from the plane of the needle, s'the arc of a‘circle in ‘this lamima at the distance r from the axis of rotation,,R the radius of the copper cylinder, t its thickness,.c the distance of its.upper surface from the needle, and @ the distance of the pole of the needle from its centre: then the whole force with which the cylinder urges the needle will be proportional to : Te. Although this may be integrable, the integral would be in so complicated a form, that it would be very ill suited for compa- rison with=the results obtained from observation; but if we consider-only the annulus of the copper immediately under the pole of the needle, which will be the most efficient part, we may readily make this comparison. For calling ? the deviation, we wah Wo DOC a Bi 14-4 eet heel? acon, sahil should have sin, 0 os pice’ x const. or sin. § = ( Kaen epee < di ag vileooiey ecldy 4 sin. 6. ' x const ; and consequently ; To = const. | 4 wor ators pee Vet c3 (c + t)3 From my ‘experiments being 1, 1 should obtain the followg’ - values of ——#* [qe sin. 6 frit 6 ie rtd pa 4 a @a ty Rs 3 Py D0 Sapte tt S074 Oe 14 26341 FRE" “6'10'_ °2-6409' + Mean 2-505 teaser? 2, 14° 10 2°8144 | sade pe 29 20 271040) : Although’ there -is a considerable’ difference in‘ the numbers, especially the last, yet as. the parts whose action 1s not.consi- dered liave here the greatest effect, and all the observations are liable:to €trors arising from the: difficulty -of'making the copper revolye swith the same velocity in allcases, I think the agreement New Series, vou. Xt. S 258 Mrs Christie‘on the Magnetism developedin [Oer. is sufficiently néar fo indicate! that the copper acts as I have supposed, A thick coppersring would be best i i for obtaining results for comparison; and when I have leisure I propose making use’ of one.) i ite ‘or the purposé of determining the law according to which magnets act upon a copper dise at different distances, I sus- pended, successively, two copper discs over the bar magnets placed horizontally by the side of each other, with their poles of the same name adjacent. Thé magnets were made to revolve until the torsion of the wire caused the dise to return in the contrary direction, when I considered that the force of torsion would be double the force with which the magnets urged the disc. The time in which this took place was noted, and also the degree of torsion. After this the magnets were made to revolve again with the same velocity, and the torsion noted where the disc remained stationary by the action of the opposite forces of torsion and of the magnets, This was done at several distances ; and those distances, between the magnets and the disc ascertained very accurately. In the observations with the disc which I have named A, the magnets were made to revolve with two different velocities; one of nearly 12 revolutions per second, the other of nearly 24 revolutions per seeond; but: with the disc C the magnets always revolved with the velocity 24 revolutions per second, as I found that I could keep more steadily to this velocity than to the other. The length of the suspending wire (No. 22) was the same in both cases: 34:25 inches. The thickness of the magnets is one-fifth of an inch, so that I have added ~1, to the measured distances between the upper surface of the magnets and the copper, to reduce them to the distances between the plane of the copper and a horizontal plane passing through the axes of the magnets. — It is evident from these results, that the force with which the magnets urge the disc, as the distance increases, decreases much less rapidly than in the case of the copper-plate revolving. If we suppose it to vary as —_ then calling c and c’ two distances and T and T’ the corresponding torsions, which are equal to the . — ] Dore forces of the magnets, 2 = a log. c rey log. c Comparing the preceding results, the several values of x will be, 1826.] Copper and. other Substances during ‘Rotation. 259 Disk A. Disk C, 1-923 1°285 1:995 1°556 2°087 1-°864. cy 207 1 2:065 2°436 2-118 Values of ne 9-499 9-406 | 2°658 2°614 2°420 2803 2°83] 2-998 \3°354: 3°246 _. These differ too widely from each other for us to suppose that ‘the force varies as any exact power of the distance; but the approximation is evidently towards the inverse square. Witb regard to the forces with which different discs are urged at the same distance, they appear to be very accurately pevarhopel to the weights of the discs when their distances rom the magnets are small; but as the distances are increased, the forces appear to increase in a greater ratio than that of the ' weights of the discs. ad Distance Goi out fe} 16 DPE SOVQG pee = 1372 -483 +194 +100 .-049> DiskA: Weight 7 Torsion Weight As it was only by a rough estimate, that I considered the velocity with which the magnets revolved under the disc A was double in one case of what it was in.the other, f would not, from these observations, pretend to determine the ratio of the forces as depending upon the velocities, but I should have little doubt that they are proportional. . From these experiments it appears, that the time in which the ‘disc begins to return, by the torsion of the wire, is the same at all distances; and from another experiment, it appeared to be independent of the velocity of rotation. This ought to be the case, the force accelerating the disc being constant; and the retarding force, the torsion, varying as the distance from a fixed point. | W. B. 1380 633-286 +134 067) Disk'B. ~ § 2 260: Mr. Graham on the Heat of Friction. [Ocr. sh omntosls old ta a: oigie & i Sadly choi - Articie III. UM ) - On the Heat of Friction:» By T. Graham, MA. (To the Editors of the Annals of Philosophy.) Ir is generally allowed, that the heat extricated in friction is inexplicable upon the theory of the materiality of heat, as at present entertained. It would be easy to show that this heat does not arrive at the bodies rubbed together, by the ordinary and admissible methods of conduction or radiation, or, ‘that no réduction of bulk takes place, or diminution of capacity for heat. Yet the materiality of heat is involved in the principal doctrines of chemistry, while the simplicity and easy application of the theory render its establishment exceedingly desirable. In these circumstances, an attempt to reconcile the substantial existence of heat with its appearance in friction, may not be unworthy of attention, even although the suppositions on which it is founded should be altogether novel; a fibidtatiney as they do, other departments of science. BS abet Heat is observed by us, eitherradiant'in motion, and possessed of great velocity ; or in union with matter, and capable of regain- ing this velocity. \ mae “Probably this velocity is necessary to its entering into bodies and) uniting with them; at least we never observe heat do so without it. For, when communicated by radiation, this’ is evident ; and in conduction, which in close contact supplies the place of radiation, it is evident that heat is communicated with a force. Indeed conduction may be reduced with considerable plausibility to an internal radiation. Be It appears that this motive power, which is essential to the communication of heat and our perception of it, is really never annihilated. It disappears when heat passes into a body, but it is merely overpowered for a time, a | not altogether lost; for upon reduction of temperature, the heat emanates from the body, evincing its pristine velocity. We may compare the state of the heat in union with matter to that of a bent spring, or a com- preenee elastic substance, the attraction of the matter for heat eing the restraining force. Sensible heat, therefore, we never find destitute of this motive power, nor to lose it—at least heat is never so divested of it as to be incapable of resuming it. These observations prepare us for the conception of heat in'a different state from that in which it is generally supposed to exist. Let'us suppose that the calorific principle is capable, likewise, of existing destitute of this motive power; and yet not in combination with matter, which this motive power seems necessary to effect. We may suppose it capable of existing in 1826.) Mr, Graham on the\ Heatiof\ Friction. 261 a state similar to our ordinary conceptions of the electric fluid. As a fluid, powerfully repelling its.own particles, and attracting | those of other matter, spread equally over the surfaces of all bodies, independently of their composition or temperature, with- out combining with these bodies, diffused (to borrow an illus- tration from chemistry) like a drop of oil upon the surface of water, without being:in combination with it. «To the matter of heat in this quiescent state, we shall, for the sake. of conve- nience, give the name superficial heat, from its covering the superficies or surfaces of bodies. It is merely heat to which there has not been imparted that original velocity, upon which the characteristic properties of sensible heat depend. Superfi- cial heat, it is evident, must be insensible. But project it with the necessary velocity, and you render it sensible. This might result. from extraordinary accumulation of our idio-repulsive body, or its concentration upon a particular spot. Dissipation, by means of radiation, appears to be a natural effect of the repulsion between the particles of superficial heat, aggravated toa great degree. 9 aii Ly Now in friction, circumstances are favourable to the conver- sion of superficial into sensible heat, in this:manner. The surfaces of the bodies rubbed together are brought rapidly into exceedingly close contact, so that as surfaces they virtually cease to exist. - From the violent approximation, the. idio- ~ repulsive power of the superficial heat investing both the surfaces, is powerfully exerted ; so that a portion of the superfi- cial heat is expelled as radiant heat, and impinges upon the rubbing surfaces. But more superficial heat is supplied from the earth; and as long as the friction is continued, superficial heat is converted into sensible, and the bodies become hotter and hotter. Hence the heat attending friction; and the reason why more ‘heat is elicited, when the surfaces are smooth than when they are rough, their approach in the former case being more close, and the investing superficial heat more condensed. _In a course of experiments upon the heat produced in friction, © M. Haldat attempted to insulate his apparatus for that purpose, by means of non-conductors of electricity, Upon reference, however, to his paper,* it will be found, that notwithstanding the body of the apparatus was electrically insulated, with great care, yet the insulation of the machine and contrivance by which motion was conveyed to the rubbing surfaces, was overlooked. The result of this imperfect insulation was a diminution of one- third in the amount of heat evolved. New experiments upon this subject are very desirable. ) pig The theory: which we have applied to friction admits of very greatextension. We may suggest that the phenomena of elec-~ * Nicholson’s Journal, vol. XXxvi. p. 30. 262 Mr: Giaham.on the Heat of Friction, (Ov. tricity are caused by an accumulation, or a deficiency, of our superficial heat. That the electric fluid is really superficial heat; and convertible into sensible heat in the manner explained. Hence we never perceive any thing which we can call the radiation of electricity. We never find, that one electrified body communicates any of its electricity to another body ata distance’ by this means. For it follows from the doctrines illustrated, that should ever electricity (superficial heat) emanate from bodies in this manner, «it shoals in the shape of radiant We scarcely need adduce instances, in which heat, in its sensible form, does attend the accumulation: of electricity. When a powerful current of the electric fluid’is concentrated, by being passed along a thin wire, the wire is heated toa great degree, so a8 to become strongly radiant. In this way, charcoal, or-any other body, may be kept in the voltaic arc in a state of intense ignition. Here, from the great repulsive force that must attend such an accumulation of superficial heat, which will be much enhanced by the retardation of the passage of the fluid, occasioned by the imperfect conducting power of the substance, a large portion is expelled with the necessary velocity, and becomes thereby sensible heat. According to this theory, elec- trical light and heat are derived from the same source’ as’ the heat of friction; and in neither case is there any production or actual generation of these principles. doch reiiae - The simplicity of this theory is its chief recommendation. That heat, possessed of a substantial existence, should be found alone, uncombined with matter, and that this combination, ofa most elementary kind, should, at all times, be brought about by the calorific prmeciple impinging with force upon the material body, are not hard postulates. Most material substances, how- ever strong their affinities for each other, require peculiarly favourable circumstances to enable these affinities to act, other- wise the bodies appear to a certain extent repulsive of each other. Moreover, when we attribute to the matter of heat diffused over the surfaces of bodies, an attraction for’ these substances which yet does not amount to the production ofa combination, we are but extending to heat properties which all other material substances evince, in adhesion, capillary attrac- tion, &c. > TIDY ORD. It is hoped likewise, that the theory of superficial heat is not chargeable with that barrenness and want of practical applica- tion, which generally characterize. premature speculations upon abstract subjects. The knowledge of the existence of such an agent, of its influence in friction and electricity, and of its con- vertibility into sensible heat, ‘affords a clue of no small import- ance to guide us in our researches. Its application in galvanism, we shall, perhaps, hereafter, have an opportunity of exhibiting. 1826.] Dr. Colquhoun on the Art of Baking Bread. 263 EBD! eeakee Xe ; ARTICLE LWascnh: pete |. A Chemical Essay on the Art of Baking Bread. Dt z} ay ? (Concluded from p. 182.) Me taut If.’ Of certain Processes for introducing an Elastic Fluid into __ the System of Dough, without having recourse to the Panary - Fermentation. joa It. is to. the use of the sesqui-carbonate. of ammonia (the common subcarbonate) that the baker, in this department of his art, has most generally recourse; and, perhaps, also, with the surest success, as a means of duly gasifying his bread. When this salt is employed, it is almost always ina proportion varying between the quarter and the half of an ounce to the pound of flour. It is dissolved in the water which is to be employed in forming the dough, of which the proposed bread.is to be made. As soon ‘as the due proportion of ‘flour is mixed with the water holding this salt in solution, and sufficiently kneaded into dough, the composition is ready for the oven; and whether baked immediately, or after a moderate interval, to suit the con- venience of the manufacturer, the same light: spongy bread is obtained. ‘The heat of the oven operates directly in expanding the carbonate of ammonia into an elastic vapour. In its endea- vours to escape, the pent air opens up and detaches from each other the compact particles of the dough; the. whole mass)is heaved up to a large increase of volume, and is maintained. for some time in a highly dilated bulk, notwithstanding the constant escape of gas, which 1s forced out into the oven, by the continued energy of the elastic fluid, until it is almost entirely, expelled from'the bread... When the whole has nearly, evaporated, the bread subsides a little ; but it has already attained, through the continued heat, a degree of stiffness and dryness through, all the ae of its texture, which prevents its shrinking back to: nearly its former dimensions. . It remains not only increased im bulk, but also light and porous. ) : ‘» But the structure of bread which has been thus prepared, and indeed. of ‘all bread in which a sudden formation and develop- | ment of elastic fluid has been generated within the oven, differs remarkably, when examined, from that of a loaf which has been made after the preparatory fermentation by yeast. Bread which has been raised with carbonate of ammonia, is certainly porous, ‘and the’ pores are numerous and excessively minute ; but that which has been ‘prepared from regularly fermented dough, 1s not so properly porous as spongy and vesicular. And the former kind of bread never presents any trace of that stratification, of a vesicles, which is held so high in the estimation of the er. | 264 Dr. Colquhoun’s Essay [Ocr. lt is generally supposed, that after passing through the oven, the carbonate of ammonia has been so eompictaly dissipated by the: heat, as to leave no traces behind of its having ever been present in the bread, except a light tinge of yellow colour, and a slight, unpleasant flavour, which latter quality is easily disguised, in all confectionary, by the use of a little sugar. But in addition to these vestiges, a small portion of the salt itself almost constantly lurks in the substance of the bread ;) for it has very generally a strong odour of ammonia when taken fully baked from the oven; and, though for the most part it becomes inodorous when cold, yet on being again heated, the presence of ammonia is again indicated by the smell. Itcan only happen, however, in cases of the most extreme carelessness that any such quantity shall remain behind, as may tend either to affect sensibly the flavour of the bread, or to prove injurious to even a delicate constitution. | ruth Nothing can be simpler in its operation, than the sesqui+ carbonate of ammonia, as to the mode in which the dough pre- pared with it becomes filled with a large supply of elastic fluid as soon as it is placed in the oven. Without dwelling any longer upon it, therefore, let us proceed to consider another mode that has been proposed for gasifying bread, and which, perhaps, derives its principal claim to regard from the circum- stance, that it has gained the support of more than one chemist of eminence ; for it has herd’ yet been found of much practical efficacy, nor does Sonne likely soon to become so. vit The process alluded to, is that of impregnating the dough artificially with free carbonic acid gas, at the very commence- ment of the baking process, when the flour is originally mixed up with water; and it has been supposed that the carbonic acid thus introduced will have the effect, in. consequence of the expansion which it suffers in the oven, of communicating!a sufficient degree of vesicularity and lightness to the bread. ‘The possibility of expanding dough by saturating it in this manner with carbonic acid gas; has been long asserted by various authorities of a more or less questionable description ; but Mr. Edlin may be said to have been the ‘first person who brought it forward, ina formal manner, into general notice. In his Treatise ‘on the Art of Bread-Making, p. 56, it is stated unqualifiedly by this author, as the result of repeated trials, that if warm recent dough and some flour be kneaded with a saturated aqueous solution of carbonic acid gas; and if the mass of dough thus prepared be placed in a warm situation for about half ny it will expand, exactly like dough in a state of regular fermenta- tion; and that if it be now baked in the oven, it will yield.an | excellent light porous bread, not distinguishable in quality from that obtained withthe assistance of yeast. He quotes also in support of this, certain accounts which have been published of the employment of yarious mineral springs in baking bread; 1826.] : on the Art of Baking Bread. 965 particularly those of Gonnesse, as ‘used in the, beautiful bread witl which the inhabitants of Paris have long been extensively supplied from that town ; of Selzer, in: Germany); and of two othersinear Saratoga, in America, which, owing to their being naturally impregnated in a high degree with carbonic acid gas, serve'to the surrounding district as a perfect substitute for the fermentation of yeast in the manufacture of bread. Allof which facts, if strictly correct, certainly tended to establish the theory of Edlin, which was, that the activity of yeast in exciting the saccharine fermentation of dough, resides exclusively in, the carboniciacid gas with which that liquid is always nearly satu- rated) when kept properly excluded from the open air. | »eThere is another opinion deserving to be mentioned on this subject, which is pretty'much to the same effect with Edlin’s, and issaid to be built»on the respectable authority of Mr. Henry, of Manchester. This isstated in the Supplement to the Eneyclopedia Britannica, under the article Baking, where it is related, as the result of certain experiments made by the gentle- man just mentioned, “that if flour be kneaded into dough with water, saturated with carbonic acid gas, the dough rises as well, and the bread is as light and well-tasted as when it is baked with ,yeast.” It is farther added by the author of the article, that if, instead of the ordinary dose of common salt, or muriate of soda, being mixed with the dough in the usual way, its con- stituents,,soda (combined with carbonic acid, in the state of the common carbonate), and muriatic acid, in their due proportion, “be kneaded as rapidly as possible with the dough, it will rise immediately, fully:as much, if not more, than dough mixed with yeast, and, when baked, will constitute a very light and excel- - Jent bread.” »: If. these opinions were well founded, they certainly might oftenibe of noismall consequence to the baker, in saving him from the delay of the yeast-fermentation, and from much of the labour of kneading. But we find, on the one hand, however, standing directly opposed to them, the experiments of: M. Vogel, who assures us that, contrary to what has been asserted with so much appearance of plausibility by Mr. Edlin, he was unable to obtain the slightest trace of real fermentation, in dough which had been prepared merely with a saturated aqueous solution of carbonic acid gas, instead of the customary mixture of yeast and avater. He states further, that such dough, when baked, after having been kept in a warm situation during the usual time, afforded nothing better than a hard cake, which had no resem- blance to ordinary bread. And he adds also as illustrative of _ ithe general necessity of providing a sufficient supply of disen- gaged elastic fluid within the dough, before baking it at all, that, when he made various attempts to form a well-raised vesicular loaf, within the oven, by mixing flour with carbonate of magnesia, w 266 Dr, Colquhoun’s Essay | [Ocr. or with zine filings, and then kneading it into a paste| by means of water acidulated with sulphuric acid, he always met with complete failure and disappointment.* 9.0 j665 00) fn bow As it was a question certainly of considerable. interest:to ascertain how the truth lay between the conflicting statements which have just been detailed, and also of much. practical importance, to prove the effect of carbonic acid gas introduced into bread without the aid of fermentation, it) seemed a matter well worthy of attention to sangeet the point anew to’ the test of experiment. This inquiry implied, of course, a two-fold inves- tigation... It was desirable, in the first place, to determine the racticability of obtaining a well-raised loaf, from dough formed y mixing flour with a saturated aqueous solution of carbonic acid gas. To resolve this point conclusively, it was necessary to try the effect of baking such dough, both when perfectly recent, and also after having been kept for some time, in order to ascertain whether the saturated solution might in this latter . case be capable of exciting the saccharine fermentation, without the. assistance of yeast. And, in the second place, it was important to foie whether the effects of the slow yeast-fer- mentation might be imitated, with reference to the lightness and porosity of the bread, by blending the dough intimately with an alkaline carbonate, and subsequently causing a sudden disen- gagement of carbonic acid gas within its substance by the addition of an acid. The results that were obtained seem to be conclusive on both branches of the research. Four ounces of flour were made into dough with four cubic inches of a saturated aqueous solution of carbonic acid gas at the temperature of 51°. A second portion of dough was. pre- pared by mixing two ounces of flour into a paste with two cubic inches of water, at the temperature of 80°, and immediately — afterwards kneading it with two ounces additional of flour, and two cubic inches of carbonic.acid gas. For the purpose of com- parison, a third portion of dough was prepared, with four ounces _ of flour, and four cubic inches of a mixture of yeast and warm water at a temperature of about 70°. To each of these three masses of dough there were besides allowed 30 grains of com- mon salt, added, according to the usual practice of the baker, with a view to the flavour of the bread. Immediately after their preparation, a portion (about one-fourth) was detached from each, and baked in the oven. The products of all the three trials were identically the same; being a compact, unvesicular | bread, differing in no respect from what would have been obtained by treating in a similar manner a simple mixture of flour and water. Lag In order to promote the fermentative process, the remainders * Journal de Pharmacie, vol. iii. p. 216. 1826.] on the Art of Baking Bread. BEF of each’ of:the doughs were set aside, according 'to the custo- mary practice, for about six hours. » Before the’ half of this period had elapsed, the dough prepared with yeast was in a state-of strong fermentation; and ‘had swelled out'to fully thrice its original volume. On the contrary, the:two other: pieces of dough,’ throughout the whole course of the six hours, never exhibited the slightest appearances, either of fermentation or of expansion. Portions of each) were now again’ detached ; and after they had been kneaded and ‘set aside for about half‘an * hour, ina warm situation, witha view to permit a fresh accumu- lation of carbonic acid gas, they were then, baked, as before. The bread formed out of the dough which had been fermented in the regular manner by means of yeast, was light and spongy, and possessed all the characters of ordinary bread; but that which was the product of the doughs prepared with a saturated aqueous solution of carbonic acid gas, was still as dense, tough, and unvesicular, as in the first trials that had been made, imme- diately after the intermixture of the flour with the water. There still remained a portion of each of the three original masses ; these, after having been again abandoned to themselves in a warm situation, as before, for about twelve hours, were carefully examined ; but even at the orpueton of this period, those which had been prepared merely with flour and a solution of carbonic acid gas in water did not appear to have undergone any fermentation or expansion. The same series of experiments was afterwards repeated with no other variation than this, that brisk soda-water was substituted in the room of the original solution of carbonic acid gas. The results were identical in every respect with those which have been just detailed: it would be unnecessary, therefore, to enter into a more particular account of them. : | Digg doa gts ‘The conclusions from all these experiments are, therefore, wholly inconsistent with the opinions of Edlin, and those attri- buted to Henry, and seem to: be a convincing proof, both that carbonic acid gas is incapable of exciting the panary fermenta- tion, and that it is impracticable, by the mere employment of a saturated aqueous solution of carbonic acid gas, to cause the nar to expand.in the process of baking into a light, spongy The experiments made on. the decomposition of an alkaline © _ carbonate within the substance of the dough, afforded results rather more favourable to the views of Messrs. Edlin and Henry, although they atthe same‘time proved decisively that this pro- cess by no means possesses the efficacy which is ascribed to ‘it in ‘the statements of these chemists. The carbonates which « _ were’selected for the purpose of these assays, were the sesqui- _ carbonate of soda, and the common carbonate of magnesia, and due care was always taken to employ the acid and alkah in 268 Dr. Colguhoun’s Essay. {Ocr. those proportions, in which they. pretty exactly saturated. each aren The mode in which these experiments le conducted, was by first intimately, blending the flour;with the alkaline car- bonate, in the state ofa fine, powder, and;next making,,this mixture into dough with the requisite quantity of a water holding the acid in solution, And especial care was taken during) the kneading to confine as large a quantity of gas as possible within the dough, in order to give the system a fair trial, The mixtures employed in these experiments were, respectively, in the four proportions following : , . (it pherds@i de On 1,— 4 ounces flour, | 42 grains sesqui-carbonate of soda. 90 grains dilute muriatic acid. By previous experiment, this quantity of dilute acid had been ascertained to be requisite to saturate exactly 42 grains of ses- qui-carbonate of soda. | ssn tg dani Beles 2.— 4 ounces flour. : a y fh ies 20 grains sesqui-carbonate of soda. rt 19 grains tartaric acid. 3 \ 3.— 4 ounces flour, 30 grains carbonate of magnesia. 15 grains tartaric acid. . 4.— 4 ounces flour. |. ig 60 grains carbonate of magnesia. 30 grains tartaric acid. . These several masses of dough, after being duly kneaded, were set aside for about 20 minutes, so as to afford full space for a sufficient reaction to ensue between the acid and the ear- bonate ; they were then baked, in the usual manner, in an oven. During the process of kneading the specimens of dough into loaves, they had all of them felt loose, light, and spongy, to.an uncommon degree, and they were also vesicular and bulky when first introduced, into the oven, These characters plainly indi- cated the sudden generation of a great volume of elastic fluid within the dough. Yet in every instance the bread formed from them proved doughy and sad, possessed but a few diminu- tive vesicles, and was never piled. Of all the varieties, that in which the flour had been mixed with sesqui-carbonate of soda — and tartaric acid approached the nearest to a good loaf, and might have been termed light or porous when, compared with bread made of unfermented dough. But even this specimen in point of true lightness and elastic vesicularity was decidedly inferior to our common loaf-bread. | sochalen _ Indeed it seems plain, from reflecting on the use and necessity 1826.] on the Art of Baking Bread. 269 of the present laborious ‘process of kneading, that’ no ‘loaf-bread can ‘be’ well ‘made by any of the extenipofaneous systems above considered, because they are all inconsistent with the thorough pie) of the dough. It is this process which is found to reider dough at once elastic’ enough to expand when carbonic acid gas'is generated within it, and cohesive enough to confine this gas‘ after it is generated. In reality, according to’ the resent ‘system, almost the whole gas which is used in the mak- ing of each loaf is actually generated within it, by a continuation of the regular panary fermentation, after all the processes of kneading have been finished. For/the loaf, after having been weighed-out, kneaded, and shaped, is set aside until it expands serene to a double bulk, preparatory to its entering the oven. ut of course when dough has been artificially impregnated with carbonic acid gas under any of the methods lately considered, asthe gas has not the'slightest affinity for any one constituent of thedough, itis impossible to subject thatsubstance to athorough kneading, without literally squeezing and expelling out of it al- most every particle of the air; and when this has once been fully accomplished, as it infallibly will be in the common process of thorough kneading, the internal supply of elastic fluid can- not be afterwards renewed, because the temporary cause which produced it is no longer in existence.» Thus.the baker who should attempt to use it, seems reduced to the hard alternative, of either abandoning the kneading process altogether, in which case he will never obtain a single piled or even well-raised vesi- cular loaf, or adhering to the kneading, in which case he will lose even the little benefit which the carbonic acid gas would otherwise have conferred, and obtain a bread, doughy, compact, and sad. But although the water of acidulous mineral springs is inca- pable of being used by the baker with success in forming good ordinary bread, there is another manner in which he often ‘employs the simple element as a means of procuring for him the desideratum of gasified bread with considerable effect : for its vapour, ‘expanded in the oven, is often a useful agent in raising many kinds of bread. When the vapour of water is thus to be employed as the expanding agent, it is customary to give an. adventitious degree of adhesion to the particles of the dough, by making it of thinner consistency than usual, and by mixing’ up with it some glutinous or gelatinous substance, as eggs, an aqueous solution of isinglass or gum, or any gelatinized amyla- ceous substance. It is by.no means unfrequent, however, to add>also a small proportion of carbonate of ammonia, in order to assist the vapour of water in acting as the expansive principle inithe oven. | There) is nothing very peculiar or remarkable in the general’) application of these means of expansion: ‘But’ there is one’ instance of its use in forming a product) with which-every’one is 270 De, Colguhoun’s Esstiyy [Oor. familiar; dnd in which the address of the mechanic is so conspi- cuously shown, that it seems worthy of being particularly alluded:to. I[t is in themanufacture of puff-paste that this inge- nuity is 7 and here it is probable that not only the vapour of simple water, but also that disengaged from heated butter may be called into operation. nea wit ay his The requisite quantity of dough is first of all made up ia the usual manner ith flour and water, and witha small quantity of butter in its,composition. After being sufficiently kneaded; it is rolled out into a flat plate, and the whole of one surface is spread over with a thin coat of butter. When this has been one, the plate of dough is folded together, cate being taken that the upper.and under surfaces exactly correspond in size to each other, while there is of course one layer of ‘butter between them. The baker now again rolls out this double plate: of dough to cover as great a space as before, and the upper surface is again spread over with butter. The doubling of the double plate is now repeated, in a similar manner, when, of course, there are four layers of dough above each other, with :a little butter intervening between each two layers, and keeping them separate. This alternate process of spreading out into a thin late, and then doubling up first into two, next into four, next into eight folds, and so on, is repeated for about ten times, by the last. of which the original mass of dough obviously consists of about a thousand thin lamine, lying parallel sboied one another, and having a layer of butter interposed between each. When this is put into the oven, the elastic vapour disengaged from the water, and from the butter, insinuates itself between each of the thousand thin lamine, and being prevented, in con- sequence of their tenacity, from a causes them to exfo- liate from each other, and thus ultimately swells up the mass into a puff; and when the baking is completed, the bread is found to be extremely light, and to consist of an aggregation of very thin membranes, no two of which are in a state of thorough coalescence, but on the contrary stand out distinct from each other, with even a pretty large volume of intervening air. From this mode of preparing the puff, it is plain that in each plate of dough, which has never been fermented, there is but little light- ness or elasticity to be expected, since the gaseous fluids. which distend and puff out all the plates between which they are confined, nevertheless do not penetrate thoroughly into the system of any one; and, accordingly, upon examining any of them by itself, it will always be found of a tough doughy con- sistence, Such are a few of the methods which are either in daily use by the baker, or have been strongly recommended to him for the purpose of thoroughly gasifying his bread without having any recourse to the aid of fermentation. Some of them are not 1826.] | on the Art of Baking Bread. : 271 alittle ingenious; but the rationale of eachiis so very simple in itself; and the kind of bread manufactured is’ of so little import- ance when compared with that of the common loaf-bread, that it has'required but little time to discuss their merits. But there remains an extensive department of the baker’s art, which has not yet been considered, and which on many accounts deserves to be carefully treated of before concluding this Essay. It is one of the most curious, and certainly also one of the most difficult processes, in regard to its rationale, of all those which occur in the ‘bakehouse; ‘and the result of an investigation imto its nature seems to’ reflect considerable light upon many parts of the art of baking bread. It isthe mode of manufacturing that composition of flourand treacle, so commonly known by the name oh gingerbread, which is now to be subjected to examination. The dough of this kind of bread cannot be fermented by means of yeast; every such attempt has proved fruitless, and even though, on several occa= sions, the presence of yeast may seem to excite appearances of fermentation in'the dough, the gingerbread nevertheless which is baked from it always comes from the oven as solid, hard, and compact as a piece of wood. : 7 Of the various striking peculiarities which mark this process, it 1s’ believed, no explanation has yet been offered. - In the first attempt towards their exposition, if it be too much to anticipate that the views adopted shall be at. once complete and satisfac- tory, at least it may: be hoped that some advance is made towards an end so desirable. : | The present manufacture of gingerbread is, generally speak- ing, carried on in the following manner: The ingredients are flour, treacle, butter, common potashes, and alum. After the butter is melted, and the potashes and alum are dissolved inva little warm water, these three ingredients, along with the treacle, are poured among the flour which is to form the basis: of the bread. The wholeis then thoroughly incorporated together, by mixture and kneading, into a stiff dough. Of these several constituents, the alum is found by the baker to be the least essential, although it is useful in having a decided tendency to make the bread lighter and crisper, and in accelerating the tardy period at which the dough 1s in the most advantageous condition for being baked into bread. | For it is one of the most remarkable ‘parts of the present system of manipulation, that » gingerbread-dough, however thoroughly kneaded, almost inva- riably requires to stand over for the space of from three or four _ to eight or ten days, before it arrives at that state which is best adapted for its rising to the fullest extent, and becoming duly gasified in the oven. And experience has shown, that it may be allowed to stand over even for the period of several weeks, rather with advantage than loss in this respect. It is true, that, 272 Di. Colguhoun’s Essay [Ocr. from causes’ not well understood by ‘the baker; the» dough! of gingerbread becomes’ thus matured and ripe! for the ovenjoon some occasions much more speeaily than om/others ;) but} 1in general, if the dough were fired :at:an earlier period than;has just been mentioned, the baked: bread would «more |.cr:dess resemble in compactness a piece of wood, 'in proportion to ‘the time by whichits baking had been prematurely hastened.«» '~\) As the alum could be easily: dispensed with by; the baker, without at all materially affecting the rising ‘of -his bread in ‘the oven, it was plain that it might be laid altogether out of view in) the course of an investigation into the: peculiarities of this pros cess. And indeed that its presence obulde not have the effect of earerey the yeast-fermentation is a matter, sufficiently plain m the well-known circumstance, that it) is not» unfrequently employed in baking common wheat-loaves; to render whiter the colour of inferior flour. It was, therefore, inthe action either: of the butter, or of the potashes, or. of the treacle, or in the: combined action of these upon each other, or:upon:some, other ingredient in the flour, that the source of the uncommon results: attending the preparation of gingerbread was to be traced. And from the experiments made, it seems. to be, clearly.-established, that the mutual action of the potashes and. treacle»upon» each other is, the gasifying principle in the present process of ginger- bread-making. : ry In order to ascertain in what this principle is situated, a mass of dough was made ready, from. which. butter .was :entirely excluded, but which differed in no other respect from:common» bakers’ gingerbread-dough. After being allowed to stand over the usual time, it was baked in the oven, and, when taken from it, proved to be a well-raised gingerbread-loaf. There were next prepared several pieces of dough, having all the usual ingredients except the carbonate of potash, and it was found, that neither when baked immediately upon being: made; nér afterwards at various intervals during several weeks, did the bread come-from the oven otherwise than: solid and compact, just such as common bread is, the dough of which has never — een fermented. In the next place, two portions of dough were prepared, from both of which treacle was excluded; and in one of them its place was supplied by an equal weight of refined sugar dissolved in a minimum of hot water. .Butin neither case did the bread return in the least degree porous or vesicular from the oven; and exactly the same results were obtained, both when the dough was baked immediately after its ppregee: tion, and at successive intervals during the lapse of several weeks. From these experiments, the inference seemed, to,,be clear, that the simultaneous presence of the treacle and» ofthe carbonate of potash, and their mutual action, must be essential ' to the formation of good elastic gingerbread, |... i T2778 1826.] onthe Art of Baking Bread. 973 It was;scarcely to be doubted that the action of the treacle upon the carbonate consists in evolving’ from: ita quantity of carbonic acid! gas. But in order to bring out this point more: unequivocally, the substitution of carbonate of soda and of carbonate of magnesia for carbonate of potash, was triedyand it ynvariably neers out that the bread in these. cases’ expanded just as well in the oven, as when an equivalent quantity of car- bonatée of potash had been employed. And when, on’ the contrary, in place of these substances, there was mixed up with the dough either caustic’ potash or caustic magnesia, the bread never'expanded in the slightest degree in the process of baking, whether the dough was baked when recent, or after being kept a considerable time. From this it resulted, that the’ presence’ of ‘an alkaline’ carbonate was clearly essential to the gasifying of the gingerbread-dough ; and it seemed almost a necessary’ inference, that the rising of the bread during the baking is pro- duced: by carbonic acid gas, and that this gas is developed in consequence of some mutual action which takes place between the treacle and the alkaline carbonate.* * The following is a note in detail of the variously-compounded doughs employed in these experiments, with a statement of the general results obtained. ier, TPE OE: cowed ca chev lccanence A ounces, | i SPO. ce scces ceseoceees &S OUNCE. ‘a ee yo ae 60 grains, “Rose well in the baking: not distinguishable in appearance from that made with ordinary gingerbread-deugh. ) ‘2.—Flour......, Covrescesesees A ounces. Treacle. ....+.ssecceseees 3 ounces. MES SS ey tosis. acceded -» 4-ounces. Megheles iii ccs dics SON eA 3 ounces. i a RR eee te ee $ ounce. The bread. was quite compact, hard, and might even be termed flinty.’’ 3.—Flour...... s deseiet s aiktin dn A ounces. POMS, 6 6a < Saves herds 60 grains. Plot 206 te A ounces. Butter...... PPO ne 4 ounce. ORRIN an aia's'tn .0icnisioe ne sa. OO prains, ' These four mixtures were made into dovgh with the requisite quantity of hot water ; and. portions of each mass of dough were baked in an over, both immediately aftér’its preparation, and at an interval of five days subsequently: In both instances, the results of all the four trials proved uniformly the same, and all alike unfavourable. The bread . never exhibited the slightest indications of expansion, being quite compact and sad. It New Series, vou. x11. | ‘ 274 DA Colquhoun’s Essay ; . [Oor, It is not very easy to penetrate the mode in which the treacle ‘thus acts upon the alkaline carbonate, By farthe most-probable cause seems to present itself in the probable existence ofa ‘certain portion of uncombined acid in treacle, which,’ entering into union with the alkali of the carbonate, releases a quantity of carbonic acid gas. That such an acid does, in a greater or less degree, always exist in treacle, seems proved by omg that of many specimens which were examined in the course: the experiments just mentioned, all possessed distinet traces of acidity, and to an extent sufficient to enable them to communi- cate a red colour to vegetable blues ; but the amount of uncom- bined acid present in all these cases appeared to be very trifling, and it was difficult to aseribe to its sole agency the production of effects so striking. It eannot be doubted, however, that this uncombined acid must operate to .a certain extent im producing a decomposition of the alkaline carbonate; and it may be conjectured also, that the superiority in the expanding power of old dough is occasioned either by the additional acidification of a small quantity of the treacle, to which it would be disposed during the keeping, by its state of mixture with the flour, or by the circumstanee that the carbonic acid gas disengaged by the had also a deep yellow colour, a sickening, and very unpleasant odour, and a nauseous a gl which were probably to be ascribed to some chemical action of the potashes pon the flour. : “4 st ear “4 ounces. , Treacle ba dda aedeeedade 3 ounces, Ay fr’ ily nd TF Butter .. eteeesten Seerees 4. ounce. isitoe sit tio) Sl yoh Common crystallized car- Tey hs seksi Feb dee 124 ean i \ Flour. y ee - eseeree . Pi eeneeeveve 4 ounces, Tréacle ..co..cc0ossseesees 9 OUNCES, Butter... eceee ee CF OEY » + ounce. _ Common carb, of magnesia. 60 grains. fle ty The bread obtainéd in both of these trials possessed exactly the appearance ‘and flavour of gingerbread prepared in the usual manner a potashes. And in these cases also, the expansive Property of the doughs was decidedly improved by keeping, so that the results obtained by the substitution of either of these alkaline carbonates in the place of that more commonly used by the baker, weré, in all respects, perfectly parallel to those which characterize his ordinary process... . ; | Ci Flour cece yell icee 4 outices, MP Oacle 3 53243 3400s 526%%5s 8 Gutices, Prakter ss sacisas3i adees ez 3 ounce, Caustic potash reererery ey Tt A grains, Flour deeecces eee sees eee A ounces. Treacle .é.eeeccese epee 3 ounces ' The two doughs, compounded as above, were assayed both immediately’after their preparation, and at three successive intervals, a week being allowed to between each experiment, » But in none of the trials was the bread possessed of the least vesicu- Anrity st was, an compagh ag ifit had. been prepared without the exhibition of any’ alia “wha er, : rr if BAT AE 4pdy PAG: MM bed hPeh i Pat) Site Hy * 1826.] onthe Art of Baking Bread. 275 uncombined acid contained originally in the treacle, has thereby more leisure to penetrate into the system of the dough, and to produce a more complete separation of its particles, And it may be mentioned as a circumstance in support of this explana- tion, that though the period of keeping requisite in the prepara- tion of gingerbread-dough is generally from five to ten days, it is.sometimes materially less, and that without the manufacturer's ‘being able to assign any cause for the variation. . But this, of course, might be readily accounted for on the supposition, that treacle generally contains a variable quantity of uncombined acid, and that this ingredient is the true agent in developing carbonic acid gas within the dough, by its action upon the alkae line carbonate. Upon the whole, therefore, it seems not impro- _ bable, that the mutual action of the potashes and treacle, out of which results the gasifying of gingerbread-dough, consists in the treacle containing a litthe uncombined acid, which, uniting with the potashes, sets carbonic acid gas at liberty, and thereby ren- ders gingerbread light and elastic. Fa | » In the course of performing these experiments, the details of which have been subjoined in a note to p. 278, and the results of which have led to the above conclusions, it was impossible not ‘to be impressed with a sense of the inconveniences that often arise to the baker from the delay occurring in the peogen and. of the injury which may not unfrequently accrue to the consumer, from the deleterious nature of one of the ingredients which is essential in the present system. This is the carbonate of potash, which it is always necessary to use in such a quantity as gives a distinct disagreeable alkaline flavour to the bread, whenever this is not disguised by mixture with some aromatic ingredient. Nor can there be much doubt, that if gingerbread, as now made, were eaten in any considerable quantity, it would prove injurious to, any delicate constitution; in consequence merely of the large amount which it contains of this alkaline substance ; and if such a cohsequence as this may follow, even in the case of the most carefully-baked gingerbread, it is plain that in the hands ofa careless or unskilful mechanic, the employment of such an ingredient is extremely inconvenient. It appeared, therefore, +o be avery desirable matter to procure some substitute, which, while it formed an equally well-raised bread, might save the delay of the baker, be less disagreeable to the palate, and quite ‘harmless 10 the constitution; and, accordingly, it was not without experiencing very considerable pleasure, that after having made various trials, a mode of compounding and pre- paring the dough was actually found out, which appears to unite vallithese advantages... The. substitute which proved the most ‘perfectly successful was a mixture of common carbonate of magnesia and tartaric acid; and in mixing up the dough, there will be found a practical scene a in employing a considerably T = 276 Dr. Colquhoun’s Essay. [Ocr. PL p OL s larger quantity of the alkaline carbonate than is strictly neces- sary to neutralize the acid. But the shortest and yore ae mode ‘of explaining how this process'is found to work, will be to quote an example of ‘its use: the following ‘statement, is therefore submitted, of the mode of preparing what will be found in prae ‘tice to be a very good dough, particularly for that: kind: of thin gingerbread, well-known under the name of parliament: cakes/' Take a pound-of flour, a quarter of an:ounce of carbonate of magnesia, and one-eighth of an ounce of tartaric acid: let the butter, treacle, and aromatic ingredients; be added'in-the same ‘manner as at present. The use of alum will not be found of any advantage, and will be better dispensed with; as itis in itself an unwholesome substance, and any good ‘effects which it can produce are in all probability completely supplied: by’ the tartaric acid. It is necessary that the alkali employed, the magnesia, should be uniformly diffused throughout the whole mass of the dough, an object which will be always best effected by intermixing it, bruised to an impalpable powder, with the flour, previously to the addition of any other ingredient. » After these have been well mingled, dissolve the tartaric ‘acid\iniia small quantity of water, and, having melted the butter, pour it, the treacle, and the acid solution, into the mixturevof flour and magnesia. Let the whole be incorporated into'a mass'of dough by kneading, and then set aside the dough, for a period varying from half an hour to an hour. It is then fit for being baked into bread. The delay of at least half an hour has;the practical benefit of giving full time for the acid to act upon the alkaline carbonate, so as to render the dough loose and shott, or, as a baker would say, to bring. it into»a ‘state of strong fermentation. The dough prepared in this manner, should never be kept longer than two or three hours before being put into the oven, from which it will in due time, be obtained, in the state of a light, spongy, pleasant bread. i : By the method now proposed, not only is the delay avoided which is so inconvenient in the system at present practised, but there is no unpleasant flavour discernible even when the bread is not at all confected with sugar.or spices, and there is no ingre- dient’ in it at all injurious to the most delicate constitution. The expense of making gingerbread in the manner above stated is a trifle greater than that. in, which carbonate, of potash is eepleres The difference, however, ‘is so extremely small; as scarcely to make any sensible addition. to. theprice of even the most ordinary kinds of gingerbread.* >: beh , - tele StanddaelD i * Tartaric acid may now be purchased -at 4s, 6d., and carbonate of magnesia at 1s. 4d. per pound: it is obvions, therefore, that the cost of,the ch gata these materials neceneary to conyert seyen.: pounds .of flour into, gingexbread,, will amount, to, only about 5d, ; ; he thei 3t bik 2H et Wh B. #i P tO 2i1 1olle feeb 3 vier 3 ? |” J find a good gingerbread, which proves. extremely agreeable to the palate, to;be 4 w 1826.} rue FAQ yaAit hg on the Art of Baking Bread. 277 obd\s a matter of curiosity, the mode. now mentioned as haying been, successfully employed, in rapidly gasifying the dough of gingerbread, ; was tried upon the dough .of plain bread, to see whether (it, might there, have the effect of proving, a complete substitute: forthe common yeast-fermentation. The result was in the highest degree favourable, and the biscuit which had been the subject.of the experiment was. as light and pleasant.as if it had;been prepared upon the fermentation-system. . This experi+ ~ ment was more, however, a matter of curiosity, as already mentioned, than of much practical utility; for although the present-process of the baker is slow and somewhat tedious, yet it is also cheap, and simple, and sure; and it is only in those comparatively rare,cases, when, either from want of yeast, or from deficiency of time, it would be impossible to have recourse to. fermentation, that the use of the process here suggested might be a matter of some advantage to the manufacturer. It should, not be omitted to mention, that the presence of the neutral salt, the tartrate of magnesia, necessarily formed by that mnion, of the:acid and alkali which furnishes the supply of car- bonic acid! gas, was found to impart to the simple bread a sslightly vapid taste ; but the addition of a very trifling quantity tof-sugar.is quite sufficient to, conceal this. . There is subjoined lini amote, ‘the process followed. in preparing biscuit with these dngredients, which is indeed so sim any particular explanation.* a a } ngredients ORO: I place of which is supplied by an equal weight of sugar. ie FOG FAP MMAEL des Wie cbwolds civic de Vides oti 1 pound. s MEME ss slic dem bee's ne daaee wae tne 4 pound. | FAW REBAR onli s cepcwccccccesces f POUNG. Rie a nek eh os ans bah ne 2 ounces, Carbonate of magnesia. .....+--++++ % Ounce. ~ WARtATIC AC1dby cae bie Ae pana ee bimee.2 ++} ounce, OCTABGER col ais ae a> danccecs cece se 4 ounce, Cinnamon........ sphapepuskoopees. Bette Wutineg fies ikea oe 1 ounce, ple, as scarcely to require ade in the form of the thin parliament cakes, from a dough composed of the following \ This composition differs from the one which is employed in the preparation of ordi- nary parliament cakes, not only in regard to the use of a substitute for potash, but also in containing a larger proportion of butter,’ and in subtracting one-third of the treacle, the These alterations, I think, materially improve the relish of the bread as a piece of confectionary ; but they are “rather unfavourable to its full ‘expansion in the process of baking. ei * ‘The dough w i+ ts as prepared with the following ingredients : MlOMR, 205 0595s solid, pin eiedi sie. siksponnd, BUer, 4.0 cccchkemeoreascwt ces ay Pi PRNES. SUGAE odd. cc wcccscces ce suena price. © OUNCES, Carbonate of magnesia ...seeeeeess $ OUNCE, IMRIAIED, ACI, @ « obo du cdpwecievien cont Ps ounce. “\o'“he flour, ‘previously mixed with’ the pulverized ‘carbonate ‘of magnesia, the sugar, “and the ‘putter, was made into dough with cold water, holding the tartaric acid in solu- tion ; and the dough, after its preparation, was set aside for about half an hour, in order °“¢6) allow’ the ‘acid to ‘act to the’ necessary’ extent’ upon. the carbonate‘of magnesia, It was then rolled out into biscuits, and baked, in the usual manner, in the oven, $78 - Dr, Colquhoun’s Essay > [Oor. * Such is the mode of preparing a well-raised gingerbread, which, out of a variety of trials, seemed by far the most success- ful; and the most advantageous, both to the manufacturer and to the consumer. But there are various other ingredients which may be effectually enough employed for the same end, and some of which deserve to be mentioned, as tending to throw light upon the rationale of the process, which is, in principle, the same in every case. | 1 iC : Thus, for example, the bitartrate of potash, instead of tartarie acid, may be employed, along with the carbonate of magnesia, When this substance is used, thete is a degree of sourness, just perceptible to the palate, in the flavour of the bread, and which. it is not impossible that some tastes might regard in the light of an improvement. Another method, and quite an effectual one, is to use the carbonate of magnesia alone, without any acid admixture, only to an extent doubly or trebly greater than when it is conjoined with tartaric acid ; and the result will be that the dough becomes as speedily fit for being baked, and : wees as spongy and as lighta bread. If again the carbonate of potash, along with an equivalent quantity of sulphuric acid, be inter- mixed with dough, it has the effect of fitting it for the oven as speedily as any of the other methods above-mentioned. But it communicates to the bread a taste decidedly bitter.* st * The following is a note of the proportions of the several compounds employed in these trials, and of the most interesting characters of each experiment. a 1.—Flouf.... ea cae Sica wa 5 aa ‘ 4 ounces. ; Treacle . .sscescececvccecsoese 35 OUNCES. ~t - Treacle... ireessweseeese - SOUnCS, Butter » oo s:ccschsnebetesses oh ck _ Cream of tartar. ......ces.--- Carbonaté of ammonia ....... 63 grains. Expansion, similar in extent with that in last experiment. But it happened here, Sse B UE, 0.0 cenccrecaces ie Gas A ounces, — Treacle sweurtrsss sa veee 3 ounces. Butter cassssccacssccasecevee: 4 ounce, Cream ‘of tartarsisssicisecess 160 grains. : Carbonate of magnesia....55.. 60 grains. Flour ..... béhevegubes Jevecee A Ounces, Treacle. ; Cee eee weer eeeee ae ’ 8 ounces, ' Patter vier bs ey eas 4 ounce, r. Cream of tartar: ....6. 0056808 160 grains. if Common carbonate it Wee by yt Ofte nna amoral | 120 grains Tuby? 4 tlw 1826.) 0 Wn the Art of Baking Breads 999 «There have now been detailed a few of the modes, in which much delay and trouble may be saved to the manufacturer, by his employing the mutual action of an acid and of an alkaline carbonate, wehich shall take a speedy effect, and generate’a due supply of carbonic acid gas within the dough, after it is made. [tis only, however, the first mentioned substitute for the present noxious ingredients of carbonate of potash and alum which can ‘he bread obtained in both these trials proved extremely porous and light; fully equal, in this respect, to the best ordinary gingerbtead, It had also a taste slightly, but not disagreeably sour. hives | | wap Ay—-FlOur. wiesiscescuscissccss.s 4 ounces, © t ap Maes sbeebs -ponape ace) 3: ounées. Ce BY + Mr Bg butter Cee eeevrepeesersvicnged 4 ounce, RPELERNp, SPST TPS CB TIC BOG. p Rae ek coe ssess. G4 Tals, fo os 5 Carbonate of potash (common). 40 grains, — (ae: ' ‘The dough'was prepared, in the usual manner, with treacle and butter, and the sul- phuric cil was sufficiently diluted with water: it was next hastily kneaded with thé carbonate of potash, which had been previously brought to the state of an’ impalpable jowder, and was then baked in the oven. . The expansion was sufficiently favourable; fh yugh rather less than is the case with ordinary dough ; but the bread had a bitterish * taste, which was quite disagreeable. ee Parry ie 5.—Flour. ip RN bed | EAR A ounces. a ry : DMOHENe, 204. fs deed creat ote 3 ounces, he f fete Butter be IN bp dBes devises _¥£ ounce, ; / ie 6) eo » » Gaxrbonate of magnesia ,......,.' 60 grains.) bi © Phe: object of this trial was to. compare thé efficacy of carbonate of magnesia witli that of carbonate of potash, as an agent in produting expansion. ‘The dough was made into"bread, -both immediately. upon its’ preparation, and also after an interyal of seyeral dave “The expansion in both casés was considerable, especially in the latter, but still rather inferior in this respect to that of ordinary gingerbread. eek? rave Gem FIOUF o 45 0405 ops decency se beces 4.0UnCES, ; TYCAC Gas Si ice cscs casecsecss & OUNCES, fis BS Citeeg chet \')) Ser eee er eo ee ere a ee ten 4 ounce. ' Carbonate of magnesia, ss.s..5.4 4 ounces FOG 4 5:4) 84 Be Uo Res b Ged ee Oe 4 ounces, AICACIC | «c's bn goihic tins sate siégn> sf ONDCER UU cases tn ttees cookess vee. & CRUE Carbonate of magnesia.......... $ ounce. . These mixtures were made with a view to ascertain the extent to which the appears ance and taste of the bread would be influenced, by introducing into the system of the dough a very large excess of carbonate of magnesia. ‘The doughs in both cases rose remarkably well in the process of baking ; fully as well indeed as ordinaty gingerbread ‘dough, ...The bread also.ate very pleasantly; and even in the second mixture, the pres sence of the magnesia was scarcely, if at all, discernible. ' Upon this account, it may prove a matter not unworthy of the physician’s attention, how far the method of baking up magnesia along with parliament cakes, may not be an advisable mode of exhibiting that medicine, The quantity used in the last-mentioned preparation was rather more than one-twentieth of the whole compound, yet its presence was far from very palpable in the cake, and it seemed that even had it been used in a considetably greater: proportion, it would not have made the bread unpalatable. A dose of that medicine might’ thus have been easily conveyed into the stomach, to no inconsis derable extent, especially in the case of children, who are well known to haye often an extreme repugnance ‘to the vapid flavour of magnesia, which besides always feels Wnpleasantly gritty when taken by itself, ~. > -~ avery 5 - owt) Soke Rok ee 280 Dr. Colquhoun’s, Essay.onthe Art of ‘Baking Bread. [Oc be considered the best adapted for practice,;both as being in ‘self.the most convenient and simple, ..and.\also: as: sai advantage of containing. no, element in the least.degree pre- judicial to health. The others have been quoted principally:to showy, the true nature of the action,which ta pes in ginger- bread-dough, in the. present tardy, process, as, well as.in the other methods. | There, is yet. ,another,process of gasification, however, which, should, be; mentioned, ,.as_| itis, occasionally resorted to.in the manufacture,of this, kind of bread,,as)well.as in that..of many. others, and with the same complete success. This is by using the sesqui-carbonate of ammonia, whose ped and the nature of whose action in, expanding, all kinds of doug in the process of baking, have-already come under our ‘notice. If this salt be employed in the proportion, of half an‘ounce to the ound of flour, the dough, containing) it, however recent. when Paked, will always form itself into.a good light breads.and itis on this account a very common practice with the baker to add a certain quantity of it to his. ordinary gingerbread-dough, when he is under the necessity of employing it-in/ its recent state, before it has been sufficiently matured. by keeping, ».. The bread so formed is found to possess| an extremely agreeable flavour, and it is also,marked by, the’ peculiarity of having ithe upper surface unusually dark and glossy... In,this bread, also, as in others similarly aérified, there remains always a certain trace of ammonia, which would be plainly perceptible, but for the confections which disguise-it, ——— »=--- -----= ? We have now reviewed some of the principal processes which are employed in the prosecution of his. art by the modern baker of bread. After briefly discussing the. mechanical details of the most ‘comnion' process of ‘bréad-making, our earliest ‘and our principal attention was directed to the fermentative process in dough, as ‘being’ by far the most curios’ and’ important in the eye both of the chemist and of thé’ mechanic. It is hoped that the trae subject of the action’ of fermentation has been ‘clearly pointed out, and also that* the nature of the secondary super- vening decomposition, and ‘that ofthe acids which it generates, have been satisfactorily explained: ’ Th inquiring into the nature of these acids, it. was impossible not .to have ,our attention directed. to, the. numerous, inconveniences’ resulting fromthe occutrence of sour dough, one of the greatest annoyances to which both the mannfacturer and consumer of bread, embracing a circle which is co-extensive with civilized society, are exposed. And_as.the, remedy here lies. fortunately, on the verysurfaces-and is at least as obvious asthe: evil isi great, a few pages’ were devoted te eneain tts eR HGAHoh, | This ‘iideed as 2 ‘maiter too, simple in itself to have required so. much:time, «wereiitenotithat its extreme)practical importance, ‘coupled withitheisingular fact of its being yet a’ practical novelty, made it necessary to verify, 1826] Mr, Goldingharh oni the: Pendulum'dt the Equator. 281 what ‘is :in ‘truth one of the most elementary principles of chemistry; by: the details of experiments, in which its operation was demonstrated in’ those’ very cases where it is required by tdecdiakeselsi indy isinpoiised athe ipad | he ~ »Wemext proceeded to consider the methods now in use for introducing a gaseous ‘body into bread, independently of the employment of fermentation ;*and the rationale of the manner in which a few of the‘most remarkable among these are found to | work, then formed a subject of investigation. But the most interesting and) difficult process connected with this branch of the art; »was certainly that of the manufacture of gingerbread, with which the Essay has ‘concluded. The different experiments which have been detailed in regard to this important department of the art of bread-baking, it is conceived, will tend to throw considerable light’upon the ‘chemistry of the process, of which there: does not seem to have been yet offered any complete solution. = | | } . 1f-the perusal of this Essay should have the effect of inducing the: man of science to direct his knowledge, more to the practi- cal exposition and improvement of so important an art as that of baking bread; or if it should convey to the mechanic any hints: which he will find really useful to assist him in his busi- ness, or to guide him in his inquiries, the author will then have obtained all the success which he ventures to anticipate. Ok 101 MiiGe wo c ° '¢ MOU Bo4e sdileds undhous aihica uit PU PRCEGR Mats Report of the Length of the Pendulum at the Equator. By John Goldingham, Esq. FRS. From Experiments and Observations ~ made on an Expedition fitted out under his Direction, from the _ Observatory at Madras: by Order of the Madras Government an the Year 1821. Together with a Deduction of the Figure ) g the Earth, by combining the Equator, Madras, and London “aperiments. Also the Geographical Situation of different ‘. Places seen on the Expedition.* In order to ‘give the greatest possible value to the experi- ments; which have lately been completed for ascertaining the length of ‘the pendulum, ‘and’ thence the ficure of the earth, it was essential to have'the length of the pendulum at the equator \\#p Acfew copies. of this Report, published at Madras in 1824, having been received in’ England, but no account of the expedition, or of the results obtained by it, having yet been given in any scientific journal, or other readily accessible medium of information, dur readers will hot be displeased at being presented with Mr. Goldingham’s report, Verbatim together with a selection’ of tables, &c. containing the results. Some parts of the, Report may perhaps appear, tedious; but we think it due to Mr. G. and his ob- - Servers, to afford those who are interested in the inquiry the full means of estimating the- Value -of the results. Edit. ENON W: PU MidS ve" ee © BBR yh Mo Goldinighdm’s Report 0S. [Oe deduced from experiments made with the same care, and with the same accurate description of apparatus, as had been made use of in other parts of the worlds.) 60) i ee ’ With a view to this inquiry, and to make the pendulum appas ratus, which I had received from England, as useful as possible in this quarter of the globe, 1 turned my attention towards discovering a good position upon, the equator, where to have the requisite experiments made; being certain, at the same time; that the goyernment of Madras,* whose aid I proposed to ask, would order every preparation to be completed, and every thing to be done, calculated to insure the success of this interesting inquiry, It appeared to me that some one of the islands off the western coast of Sumatra would furnish a good position, ow which to make the necessary experiments; and, though person+ ally unknown to Sir Stamford Raffles, the present Lieutenant Governor of Bencoolen, I felt no hesitation in addressing him upon the subject of affording us assistance. — siongslog ~The reply of Sir 8, Raffles was such as:I had anticipated—it was dated the 5th of September, 1821; and the subjoined aré extracts from it,. Picvii ye 3 Lt TON : peed xa > , weet? GF sea Prertsh BF RIED ae BE , ; t , .. *, The pillar.to be commenced as-early as:practieable, and to'be kept from ‘rain bya © tarpauim, the object being to haye it ds;dry as possible before the clock and frame ar put up. “It is not té be plastered, as that would keep it wet a very long time—strong cement that will soon set, to be made use of, if to be obtained—as little water as possi= bleto be used in mixing the chunam, and laying the bricks, New Series, VOL. -X11. U 906. Mr. Goldingham’s Report fOor become sufficiently dry, the canvass Observatory may be placed over it, the door toey J the face of the pillar, and the face of the pillar about two feet behind the ridge pole ; the whole of the illar to be nearer the left side of the tent than the right side. he plank should be properly secured, and perpendicular to the horizon. The plank being firm, the clock may be screwed to it, which should be done in the most secure manner. The pendu- lum to be kept every way as at the a reap and the works of the clock the same ; thi arc for measuring the vibration will be a guide in placing the pendulum, the point of which should stand | division to the right of 0, and 0°25 of an inch in front of the arc: by having the face of the pillar upright and flat in the first instance, the plugs so placed in it that the plank shall also be upright and firm against the face of the pillar, the clock will be easily and firmly screwed in the position mentioned. The projecting part of the pillar on which the bottom of the clock-case stands should be perfectly level. The pendulum of the clock is first to be put up, and then the works.* If the black paper and disc should have been rubbed off, the ball of the pendulum is to be covered again, and a fresh disc put upon ‘the centre of the ball. The clock should have been going 24 hours at least before you begin to ascertain its rate; get it to as small a rate as you can without losing too much time. ° “ The frame for supporting the pendulum of experiment may now be secured. At the Observatory, I was obliged to let the back of the frame 31 inches in the wall ; the surface of the plugs having been let in beyond the surface of the wall exactly that quantity; but the clock was then placed against the wall; here, there will be a plank, which is exactly 21. inches in thickness, so that the surface of the plugs should be let in only 14 inch, and the front of the pillar, where the frame is to be placed, cut ‘away to that depth. Care should be taken that the frame is put up at first, so that the top of it shall be as nearly level as possible; and at such an height, that when the small frame with the agates is also put up, the point of the pendulum shall just come to the divisions of the arc for measuring the vibrations ; and also, that the middle of the black slip at the lower part of _the pendulum shall be as nearly as possible opposite the centre of the disc. — , a6 San “The large frame being levelled + by the spirit levels, put up ‘the smaller frame containing the agates. Let this be most accurately levelled ; screw up the Ys, and oe up the pendulum of experiment, with the knife-edges in the Ys, having first wiped * Minute written instructions were also furnished for putting "P the works and pendulum of the,clock, to make the party independent of assistance in that part of the operations. + Lead is placed between the parts of this frame; so that with the purchase of the “‘Tever, it may be flattened, and the frame thus brought into level ; it » however, be made as nearly level as possible by the workmen when putting it up. — 1826.] of the Length of the Pendulum at the Equator. 291 the knife-edges with a piece of cloth, or flannel, saturated with fine oil. This should be done before the observations are come menced, and after finishing them, the knife-edges are always to rest in the Ys, when the pendulum is not used, but to be let | down on the agates, when the experiments are making. - The small telescope is to be placed at such a distance from the pendulum, that the sides of the black slip at the bottom of the pendulum shall just be embraced by the sides of the perpen- dicular opening in the diaphragm ; large pickets with flat tops may be driven into the ground at the proper distance, and the bottom of the triangular stand supporting the telescope be screwed to these, the telescope being kept at the same height as it is in the Observatory, or a brick foundation may be laid with pickets let in: the telescope must be slid horizontally; until the left edge of the diaphragm becomes a tangent to the edge of the disc on the same side; and a mark must be made to show the position of the telescope to the left; move the tele- scope to the right, until the other side of the diaphragm is a tangent to the part of the disc on the right; here make a mark also, bisect the distance of the two marks, and place the tele- scope half way between. | putt ~ “The following is the mode of making the experiments :—The barometer being up, and the thermometer hung near the middle of the pendulum, lower the knife-edges gently upon the agates; adjust the perpendicular sides of the diaphragm most accurately to the edges of the black slip, by the screws on the brass part of the support; then bring the 0 on the arc, to coincide exactly with the angular point of the pendulum. With the forefinger of the right hand upon the edge of the black slip of the pendulum, bring the point to about 1:3 upon the arc for measuring the vibrations, and on the left of 0; an instant before the pendulum of the clock comes to its greatest height on the same side, with- draw the finger horizontally ; take the height of the thermometer and barometer, which register; look through the telescope, an assistant counting the clock, note the second and parts of a second, when the disc is completely hid behind the black slip of the pendulum ; also the instant when it re-appears; let the exact time, minutes, seconds, and tenths, of both be registered, and the meantaken. Immediately after the second observation; (the re-appearance of the edge of the disc) take the arc of vibra- tion very carefully, by seeing how much the pendulum vibrates ,on each side of 0, which also register: In about eleven or twelve minutes, the disc will again coincide with the pendulum ; the times of the same appearances as above must be noted and. registered; and thus proceed until five mean coincidences are obtained (as in the form). The thermometer being observed at “the beginning, at the third and fifth coincidences, and the baro- meter'at the beginning and a of each set. The pendulum U 2920s Mie Goldingham’s Report... °) += [Oen. should now. be gently stopped, by putting the hands at the sides of the weight, and a new set of experiments commenced as above; perhaps eight sets, fourin the morning, and four in the afternoon, may be.taken in a day: the names of the observers to be noted; and each person’s observations to be kept distinct. The forenoon sets being done, screw up the Ys, so that the knife-edges may rest on them; lift the pendulum gently up, and wipe the knifesedges with the oiled cloth or flannel, and place it again’ with great care in the Ys, covering the whole with acloth to keep off dust and damp. Before the afternoon’s observations, wipe the knife-edges, and lower them upon the agates very carefully ; should there not be light enough in the Observatory- tent, the top may be opened; but great care should be taken to exclude. wind from the pendulum during the time ago the experiments; on this account, the face of the pillar and the opening are placed on the side opposite to the prevailing wind. , “ Three distinct sets of observations, of 120 or 130.observations in each set, should be taken if possible.,, The frame with the agates to be examined and levelled between. each set, and the other points of adjustment also to be examined... | : “‘ During the time of making the experiments, the rate of the clock must be correctly ascertained, both by the stars and the sun, and all the observations carefully registered. A small pillar may be built for the transit instrument, sufficiently, to the right in the Observatory, not to obstruct the view of the pendu- lum through the telescope, -but,so as to take advantage of the opening in the top.of the Observatory for taking the transits... . _. & Meridian altitudes of the sun, if-not too high for the artificial horizon, and of stars on each side of the zenith, should be observed; the more numerous these observations are the better, as a result to the nearest second is required. borg andi * The longitudes must be found by the chronometers, and eclipses of the satellites of Jupiter. | ‘om squrcitasth uray “The nearer the place of observation is to the sea the better ; the height of the pendulum above the sea: must be, found by levelling ; also the rise and fall of the tide; the time of high water on full and change; the variation of the compass; the bearings and distances of the different mountains, the extent and elevation nearly, and if known, to note what they are com- posed of; also the bearings and distances of islands, and parts of the coast ; and particularly the nature of the soil, of the place on which the experiments are made; whether sandy, or mould, or rocky; if either of the two former, whether to any depth... “Every opportunity is to be taken for finding the bearings and. distances of places and points along the coasts which may be in sight, with the difference of latitude and difference of longitude; also for obtaining soundings, as well.as the set of the currents, as shown by the chronometers and meridian observations, to 1826.] of the Length of the Pendulam-at the Equator. 293 lay the foundation for a nautical survey, and for the improve- ‘ment of nautical science; the variation of the compass should also be found as often as possible; the log-line should be accu-. rately marked, so as to give correct. distances for bases, and for finding the strength of the currents. « The details of all the observations, experiments, and results,. to be sent to the Observatory, to. Mr. Goldingham the’ astro- nomer, by every opportunity. ney “ Journals noting every circumstance that may be thought useful or. interesting should be kept: both Robinson and Law- rence may each also be directed to keep a journal. ‘ « Memorandum of the Points to be attended to. ‘The frame with the agates to be accurately levelled. In taking the pendulum of experiment out of the case, the greatest care should be observed not to bend it; the knife-edges to be wiped with an oiled cloth at the beginning and at the end of the experiments ; the knife~edges always to rest in the Ys, when the pendulum is not in use, but to be Jet down on the agates previously to making the observations. “The point of the pendulum of experiment not to be placed beyond 1°35 on the arc of vibration before the pendulum is set going; so that the arc of vibration at the first time may not be much more, nor much less, than 1°3. | hele “The clock to be firmly secured,and quite upright: the frame for suspending the pendulum of experiment also to be firmly secured; marks have been made~ by means of the-arc on the back of the clock-case to show the position the pendulum ought to be brought to. , ! ) « Should the clock go too slow, screw up, or shorten, the pen- dulum as many divisions of the nut at the bottom of it as the clock loses seconds in 24 hours.* Should it go too fast, lengthen the pendulum, as above, by means of the nut.. — “ The clock to be wound up once a week. Tihtal'y “’The chronometers to be wound up at the same hour every day; one person to be specially appointed to do this. “ In finding the latitude, take stars on each side of the zenith. “ Equal altitudes the best mode of finding the time, though in uncertain weather, it will be as well to take single altitudes also, before nine o’clock, a.m. or after three, p.m. ' “ On the days of experiment, itis absolutely necessary to have the rate of the clock; this may be found both by the sun, and with the transit instrument by the stars. | ‘‘ In taking bearings on ship board, use the azimuth compass: allow for currents in rnaking a base of the ship’s run by the log for a given time. she * The value of these diyisigns is not exactly a second, perhaps ; but it will be found after two or three trials, a ee SUA a — 294 ‘ Mr. Goldingham’s Report = == (Oe. * Tn taking the meridian altitude ofa star, compute the exact time by the chronometer when the star passes ; set the index to the double meridian altitude nearly; and take the same at the instant, when, by the chronometer, the star is on the meridian. “ Of the sextant telescopes, always use that with the largest magnifying power, placing the wires parallel to the face of the instrument, and observing in the centre of the telescope. Screw the telescope well in towards the face of the instrument for observations of the stars; for the sun, the middle of the object- glass of the telescope should be placed opposite the middle of the unsilvered part of the horizon-glass. Find the error of sextant at the times when it is used. The horizontal diameter of the sun should be taken for this purpose, ifthe sun be low. Form for registering the Experiments with the Pendulum. — Apr. 2, a. m.—Rate of the clock. . Hygrometer. Barometer, Inches. By the sin... By the stars, 14:8 dry. sah tt ie on +h Dise re-ap- ‘Arc of vi- oe iokoay. gn or Disc hid. peared, bration, Retnarks: 81:95 41” 165741" 257 | 1:38 | 453° 125 153 21 «| 1-29 825 |5 10 |5 195) 1518 NT -10° 117-0 95] 1-08 oo 99247 129 85 122 2251 1-00 dine i ‘The above is from the experiments made at the Observatory, before the Expedition sailed. os Fea Nothing was denied that a liberal and enlightened government in this distant quarter of the globe could cause to be supplied ; and the Expedition now only waited the arrival of a Company’s cruiser, two of which had been placed for a particular service, under the orders of his Excellency Sir Henry Blackwood, the Admiral of the Stetion, and one of these was to have been spared, for a short time, to carry the party to Bencoolen. ~ About the beginning of March, finding the cruiser did not artive,* and that a good opportunity offered for sending the ‘Expedition on the ship Morning Star, I addressed government, stating, that as the season for going to the northward from Ben- coolen had commenced, it would be most desirable if the party could proceed to that place without further delay, and as there was now some doubt whether the expected cruiser would call here in time, or even at all, I proposed for the consideration of the Honourable the Governor in Council, that the Expedition should proceed on the ship before-mentioned—this was ordered * It is fortunate we did not wait longer for her, as she proceeded direct to Bengal. 1826,] of the Length of the Pendulum at the Equator. 295, immediately, and the party * embarked on the Moming Staron the 13th of March, the instruments and baggage having been sent on board the day before. 19k} | 7 The following brief Abstract of the Proceedings is founded upon re the Diaries kept at the Time. | , : - After a passage of thirty-four days, the Morning Star arrived in Bencoolen Roads. On the 18th of April, the party landed at Fort Malbro’ with the instruments and baggage. Capt. Crisp and his family were invited by Sir Stamford Rattles to reside at the Government-House.. The observers Messrs. Robinson and - Lawrence, and the conductor and sub-conductor, were accom- modated with rooms in the lower story of the old Government- House until the 1st of May, when they removed into tents about 200 feet north-east of the house. The Lascars obtained their lene from the public stores, paying for the same; and the uropeans their’s from the Bazar. On the 20th of April, Messrs, obinson and Lawrence commenced the observations, accord- ing to the instructions, which were continued during the stay of the party at Bencoolen. On the 5th of May, at about ten minutes past two, p.m. a violent and alarming shock of an earthquake was felt; it lasted some time, the motion was con- siderable, attended. by a noise, like that of the rushing of a strong wind; the old Government-House shook extremely, but does not appear to have sustained much damage: some other shocks were felt in the course of the afternoon, but not ‘so violent; the weather was clear, except to the northward over the mountains, and a fresh north-west wind prevailed at the time. On the 16th of May, Capt. Crisp, with Messrs. Robinson and Lawrence, and the conductors, proceeded to Rat Island, with the view of ascertaining its position. In the afternoon, the party returned to Bencoolen, with the exception of Messrs. R. and L. who remained, and took some meridian altitudes of stars in the night, and bearings and angles of prominent points next morning. In the afternoon they returned to Fort Marlbro’, and on the following day recommenced their observations, On the 24th of May, from a station on the turret of Fort Marlbro’, about _50 feet above the level of the sea, Capt. Crisp and Mr. Lawrence took bearings and angles of remarkable points on the lofty ranges of mountains in the interior of Sumatra. On the 31st, Captain Crisp and the observers proceeded to Pulo Bay, nine or ten miles south-east of Fort Marlbro’, where they arrived in the afternoon; here a base was measured, and some bearings and angles of objects in the interior and prominent points of the — range of mountains taken; in the evening of the Ist of June, they returned to Bencoolen. bes __* The party consisted of Capt. Crisp; in command ; Messrs. John Robinson and Peter Lawrence, observers; Mr. Hamilton, conductor of stores; Mr, Flannigan, sube onductor 5 one second tindal, and nine Lascars, : 296 . «Mr. Goldingham’s Report 0... \ [Ocr.. On the 12th of June, Captain. Crisp orderedthe party tobe. m readiness: to. embark on the brig Eleanor, the. property of the master-attendant of Bencoolen, but en d, it was under-. stood; for the -expedition—being too small for the party, an- other but a smaller vessel, belonging to the same owner, -was also engaged. On the 13th, Messrs. Robinson and Lawrence, with two Lascars, embarked on the Eleanor, taking some of the smaller instruments, and: having in view to discover an. island’at the equator suited to the purpose of making the ex- sce er upon ; the conductor and sub-conductor also em- arked on the smaller vessel. The cabin of the Eléanor was found in possession of an officer and his family proceeding, it was understood, to Nattal, and the hold was nearly filled with bricks and lime. On the 17th of June, the vessels sailed from Bencoolen roads for Nattal; on the 20th a. m. ‘they passed Pulo Brinjen, and another small island south-west of the Poggy Islands.‘ At night a very hard and continued squall came on, accompanied by thunder, lightning, and heavy rain; the party were obliged to take refuge in the hold, where, with:the hatches on, they were in danger of suffocation—the wind adverse, and. extremely violent, drove the vessel so far to leeward, that they were obliged to return to Bencoolen, where they arrived on the 23d, and on the following day, the smaller vessel returned with _ the conductors, who had suffered a good deal by the violence of the weather, in consequence of the state of their health, and had ° the greater part of their baggage rendered useless. On the 28th, Captain Crisp came on board, and ordered the instru- ments and baggage to be landed, and taken to Fort Marlbro’, 29th, Messrs. Robinson and Lawrence returned to their en- campment, and recommenced observing—having chronometers belonging to Sir S. Raffles and Captain Patterson of the ‘Ho- nourable Company’s ship Canning—besides those with the ex- pedition, to ascertain the rates of. Most of the party were at- tacked with fever during their stay at Bencoolen. . On the 2)st of July, the whole of the party, with the instru- ments, tents, baggage, &c. embarked un the Honourable Com- any’s ship Canning, Captain Patterson; and on the 23d, they left ee roads for Tappanooly, where the ship arrived on the 8th.of August, and the party landed on the 9th, to the great relief of the observors and conductors of stores, who, the diaries state, had fared -on board in a way they had by no means ex- pected. : The tents were pitched on the island of Tappanooly, near the house of the Resident, Mr. Prince. On the 11th, the obser- vations were commenced on a small rocky height at the southern extremity of the island, near the Flag-staff. On the 15th, Mr. Robinson and the two conductors, with Lascars, embarked on the Eleanor, (which, had reached Tappanooly before the Can- ning) for Pulo Panjong, where they arrived on. the ¢]st, On 1826:]. of the, Lengihiof the Pendulim-at the Equator. . 297. the 29th:of August, there was. an earthquake’/on shore, which was felt: by those of the party who were. afloat—the vessel ap-~ pearing to receive a severe shock, September 5th, Captam Crisp, with: Mr. Lawrence, proceeded to the island of Pulo Banka, near, the north-east extremity of Tappanooly bay, and afterwards to the remarkable island, called the Sugar-loaf Peak ; sights for the longitude, and bearings, and: angles were taken ; and they returned to Tappanooly, about sun-set. 9th, Mr. Lawrence. proceeded for Battoo Barroor Point, for: the purpose. of laying down its position, and the. prominent points ‘of the Mansellar Islands, together with some points of Tnidonuciee bay. The brig Eleanor returned on the 11th from Pulo, Panjong. 12th, all the baggage was sent on board the brig, and the remainder of the party embarked at sun-set for: Pulo Panjong, where. they arrived on the 16th: observations were commenced by Mr. Lawrence on. the following day at a station near the Resident’s house. On the 18th, the Eleanor sailed for Bencoolen: for another supply of materials for’ the pillar. September. 19th, Mr. Lawrence proceeded, with Cap- tain Crisp, to Pulo Telloor, where observations for the latitude and longitude were taken, and also angles of the adjacent islands, and that. part on the coast between points Kurboyee and Lubwaun Looloo—returned late at night. Another excur- sion made on the 23d, to: Pulo. Pahgaugo, for the purpose: of laying down its position ; and it was intended to have proceeded thence to the other islands near the equator, but the winds and weather having been very unfavourable, they were obliged ‘to. return on the the 25th to Pulo Panjong. On the 26th, they ventured out again for Nattal, but returned the followine day. On the 29th, at-night, Captain Crisp in one boat, ata Mr. Lawrence in another, sailed for Nattal, and proceeded to- gether as far as Pulo Tamang, where, early on the: 2d of Oce. tober, the boats separated, the one with Captain Crisp pro-. ceeding round the west side of the island, and the other taking a direct course for Nattal—the weather-and winds being unfa- - vourable; the latter strong with a heavy sea—the boat with Mr. Lawrence returned to Paulo Tamang—and on the 3d. sailed again, but was obliged to proceed to the Sumatran shore for pro-. visions, and anchored im the river at Patamm.—Next day, the 4th, having heard ‘no intelligence of Captain Crisp, Mr. Law- rence wrote to. the Resident, and received a reply late on the 5th, stating that Captain Crisp had not arrived at Nattal, and advising Mr. Lawrence to return to Pulo Panjong—the weather. very unfavourable at the time for vessels of any description to. roceed to the northward. At sun-rise on the 6th, they sailed, nil yal for Pulo Panjong, and fortunately arrived in the after- noon, Captain Crisp having also returned.. On-the 4th, at 10 a.m, the weather: being cloudy at the time, a‘shock of an earths. 298 Mr. Goldingham on the Pendulum at the. Equator. fOcr. yoke ye felt, which is stated to have given the earth an un< ulatory motion for some minutes--another (but a slighter) shock was felt shortly afterwards; these sh appeared to come from the east, in the direction of Mount Ophir. On the 6th, at might, two vessels, one with Captain Crisp, and the other with Mr. Lawrence on board, sailed for Nattal, and ar- rived late at night on the 7th. On the 8th and 9th, observa- tions made, On the 10th, in the morning, the position of Nattal Hill was laid down. In the evening they left Nattal on the packet-boat for Pulo Pinnee, arrived at sun-set on the 11th, and anchored :close to a coral-reef, the water on which bein too shallow, they proceeded to the land, the south-east part o the island, in the small boat, where observations were taken for the latitude and longitude; they returned in the evening to the packet-boat, and sailed for Pulo Panjong, where they arrived on the 15th of October. Early on the 23d, the conductor and sub-conductor, with a great part of the baggage, embarked on the packet-boat, mo Mr. Lawrence on the small boat, for Pulo Pinnee ; but, owing to. adverse winds, and bad weather, were obliged to return on the 26th to Pulo Panjong. The Pa- dres, a sect of Musselman fanatics, being expected to attack our possessions on this part of the coast, Captain Crisp was appointed toa command by Sir Stamford Raffles. On the 31st, that officer and his family embarked on a brig for Nattal.. Ob- servations for the rates of chronometers, and for the latitude and longitude, were commenced, and sketches of the coast made. The Eleanor returned from Bencoolen on the. 5th of November. On the 17th of November, Captain Crisp arrived in a small boat from Nattal. On the 19th, aptain Crisp in one boat, and Mr. Lawrence and the conductors in another, sailed for Pulo Pinnee; the night having been very dark, the boats arted company, and the latter went on past Pulo Pahgaugo as ar as Tooleechemanah Point—the wind being strong, with a heavy sea, they were obliged to make best of their way back to Pulo Panjong. Atsun-rise, made another attempt to proceed to Pulo Pinnee, and arrived at the south-east extremity on the 23d— landed and commenced cutting down trees, and mf a place for the tents. On the 26th, the brig Eleanor, having left Pulo Panjong on the 21st, arrived with Captain Crisp and Mr. Ro- binson, the greater part of the instruments, tents, and baggage ; the brig anchored about five miles off shore. In the course of the day, Captain Crisp, accompanied by the sub-conductor, came on shore in a boat, and afterwards returned to the brig, with the intention of sending the struments, and all the other articles, on shore in the morning; but there having been very heavy squalls from the north-west at night, during which the only two boats they had were lost, it became impossible to Jand any thing, and the Eleanor was, therefore, got under 1826.] Sir James Hall on the Consolidation of the Strata, 299 weigh for Pulo Panjong, and did) not return until. the. 7th of December, having touched at Nattal. On the 8th, Mr, Robinson and the sub-conductor landed with a part of the baggage; and by the 9th, in the evening, all the.articles were on shore, and the tents up. On the 10th; Captain Crisp came on shore; they observed for the latitude, and found the south-east point of the island nearly five minutes north of the Equator. On the 11th, Captain Crisp sailed for Pulo Panjong, leaving directions for Mr. Lawrence and the conductor to proceed to a small island to the south-east, and to examine if it was suited to the purpose we required.* Early on the 16th, Mr, Lawrence proceeded to the island, with the requisite instruments, anda bag- gage-tent, also three Lascars, and landed about three o’clock an the'afternoon. The conductor having been sick was, not able to accompany the party. On the 17th, they examined the island, found it 11 feet above the level of the sea, composed of sand seated upon a foundation of coral, in length 365 feet, and breadth 200 feet,’ distant from the main land about 10 leagues, “with a good landing-place, and suitable in every respect for making the experiments upon; having dug a hole tothe depth ‘of seven feet, they found very good water, and in abundance— there being no other islands in the vicinity nearer to the Equator --than this. On the 18th, Mr. Lawrence returned off Pulo ‘Pinnee, and on the following day, Mr. Robinson proceeded, with “apart of the baggage, for the small island, which is: called ~ Gaunsah Lout, where he landed; Mr. Lawrence and the com- ‘mander of the brig sailing at the same time in a smaller boat, which, having been found too deeply laden, and bad weather coming on, they returned, and did not reach the small island ‘until the following day. The instruments and baggage were got to the island by the 7th of January, and the Observatory ‘Was put up. | | | BP ay rons i (To be continued.) ArticLe VI. On the Consolidation of the Strata of the Earth. By Sir James : Hall, Bart. F.R.S. Lond. and Edin.+ a: Tue public attention, animated by scientific controversy, has of late years been much directed to Geological subjects; and. _ * It appears from a letter of Captain Crisp’s, which was despatched by a circuitous route, and which I did not receive until the end of last September, [1823] although written many months before, that,‘at this time, his health had suffered very materially by the labour and exposure attendant upon going about, and in an open boat, in search - . of a proper station for making the experiments upon; some of his family were also jill at the time at Nattal. From the Edinburgh Philosophical Transactions, vol. xs part ii, 300: Sir James Hall on the Consolidation of the Strata. [Ocr: the certainty of many important facts has in consequence been ascertained beyond dispute, which were formerly unknown, or at least involved in such obscurity, that no person could. have ventured to assert them, without ‘being charged with extrava- nee. But though, no doubt, many branches of this science. still remain to be investigated, such inquiries may now be said to have acquired a considerable degree of consistency and in- terest, from the substantial basis upon which they have been found to rest. Thus, in the present day, it is universally admitted, that a at part, I believe, in point of bulk, by far the greatest part, of the solid rock which constitutes the external mass of our globe, is stratified : that these strata, or at least.a considerable ortion of them, have at one “pag consisted of a loose assem- lage of sand and gravel, broken from rocks of*still higher anti- quity : that these fragments. are infinitely various in quality, in bulk, and in form; some. retaining their original sharpness, others rounded and polished by agitation in‘ the water : that these beds alternate with others. of limestone,composed, in a ‘great measure, of the shells of sea-fish, which ‘shells are also wccasionally scattered through the other strata. So that on the whole, it seems to. be sscertained to the satisfaction of all par- ties in geology, that the strata,—those, at least, of later forma- tion, have. once constituted collections of incoherent parts. _ And if:is further. admitted, that these beds have undergone va- rious remarkable changes, some chemical, some mechanical. The chemical changes consist m the consolidation of these Joose assemblages into their present state of rock, passing, in that transition, through Scmibdiia varieties, in point of flexibility and toughness, and occasional brittleness. The mechanical re- yolutions are no less remarkable, principally in the change of the strata to their present contorted shape, and elevated position, often many thousand feet above the surface of the sea; though there is full reason to believe that they all once lay in a hori- zontal position at its bottom. * | I have said that the greatest part of the crust of our habitable globe seems unquestionably to be stratified, and produced from detritus or fragmented materials. The other portion, though | probably the least in bulk, is, generally, the most conspicuous, owing to its durability, elevation, and picturesque beauty. This ‘kind of rock is contrasted with the former class, particularly in ats wegative qualities ; in being, according to some geologists, altogether devoid of stratification in the general mass, and en- tirely free from component fragments; the whole being made ap of crystalline forms, moulded upon each other, in obedience to certain chemical laws. | , This crystalline rock, as the Society are well aware, abounds in the neighbourhood of Edinburgh; in Arthur’s Seat, Salishury 1826.] StrJames Hall on the Consolidation of the Strata, 30} Craigs, and.in Corstorphine Hill., »It.is. decidedly posterior to the stratified class, of which it penetrates. the crevices at all angles, in the form of dykes or veins, like stucco cast. in a mould; frequently also.lodging between the. strata in vast shapeless masses. y , ‘ As the rock in question never fails to preserve this quality of universal and. perfect’ crystallization, I heartily concur with Dr. Hope.in bestowing upon it the general name of Crystallite, un- der which. are comprehended all substances of this kind,, in- cluding not only Whinstone and Basalt, but also Porphyry, ‘Granite, and Sienite.of every-description. sau elas The solid, mass of our globe, then, in so far as.it is. naturally exposed to our view, or has been penetrated by the labours, of the miner, would appear, (with,the exception of some streams which have flowed from. Vesuvius, Lipari, and other, volcanoes, in which the rock possesses a glassy structure), to be compre= hended under these two classes, Aggregates and Crystallites. The whole of these rocks, of both classes, furnish, at every turn, proofs of their having undergone revolutions of the utmost magnitude; and much ingenuity has been exerted, in endéa- vouring to trace these changes to some consistent and rational system. But of all the active powers of nature, one only has. occurred to me as capable of affording a solution, in any degree satisfactory of the phenomena,—! mean the power of internal heat, which, in all ages, and in various countries, has made its appearance at the, surface of the earth, not unfrequently from under the ocean, and which still, in our own days, gives occa- sional proofs of its unabated activity. sin ag ae pci tas To ascertain the reality and. sufficiency of this agent, and to trace the volcanic fire to its. source, with tolerable probability, is, doubtless, an object of great interest and, curiosity ;, but it has always appeared to me, that the progress of geology was re- tarded by a premature anxiety to enter into such investigations, Taking it. for granted, however, as, indeed, no one can dis- pute, that there frequently do arise violent exertions of heat from under the bed of our ocean, Dr. Hutton held that this might furnish a rational and sufficient theory of the earth, with- out entering into any, inquiry as to the origin of that heat; and admitting that there are many. geological facts which cannot be accounted for by such a fire as that of Vesuvius, now acting at the surface, in free communication with the air, he contended that the case may be very different, where that same cause acts | at the bottom of a deep sea, and under various modifyizg cir: cumstances, by which its operation could not fail to be influ- enced, ii rene ~ . _ This; indeed, constitutes the essence of the Huttonian Theory, which I learned principally in conversation. with its illustrious author;..and which, since his death, I have taken every means 302 Sir James Hall on the Consolidation of the Strata. [Oor. of submitting to a variety of chemical tests; being for ever on the watch for such natural scenes as might illustrate these prin- ciples, as well as for opportunities of making experiments, to determine whether such modifications on the action of heat were, or were not, sufficient to justify the expectations of Dri Hutton. : 2 Ri aOR; ' It was in prosecution of these views that I formerly under- took a set of experiments, proving, I believe to the satisfaction of the scientific world, the identity of Whinstone and Lava, of which a full detail is given in your Transactions. In farther illustration of the same topic, my experiments on Carbonate of Lime were formerly undertaken, by which it was shown, that calcareous matters, exposed to heat under pressure, might be fused ; and, on cooling, would erystallise, so as in every respect to resemble marble. To these I beg leave likewise to refer the Society, | ' . The immediate object of the paper I have now the honour of submitting to the Society—the consolidation of the strata—has been pursued in a similar spirit, and with similar views to those formerly announced. In making efforts to trace the modifica- tions which the action of heat would undergo, when compelled to act under the influence of compression, or of other cireum- stances, all of which, in company, I have always been willing to distinguish by the name of Plutonic, See the term was originally suggested, ironically, by one of our keenest antago- nists, the late celebrated Dr. Kirwan), I was led to the par- ticular topic of this paper, by an unexpected scene which pre- sented itself in my own neighbourhood, in the country. _ It had often been urged, and apparently with good reason, against this branch of the Huttonian Theory, that no amount of heat applied to loose sand, gravel, or shingle, would occasion the parts to consolidate into a compact stone. And as all my experience led to the same conclusion, I saw that, unless, along with heat, some flux were introduced amongst the materials, no agglutination of the particles would take place. The Raine circumstance above alluded to, as occurring near Dunglass, an which will be particularly described presently, having suggested to me the idea that the salt of the ocean might possib y have been the agent in causing the requisite degree of fusion, I insti- tuted a series of experiments, the details of which I am about to bring before the Society. By these, I conceive it will be shown, that this material, under various modifications, is fully adequate to explain the consolidation of the strata, and many other effects which we see on the surface of the Earth. ' My success, from the first, was such as to promise the most satisfactory result, though it is only within the last year that I have been able to command the repetition of the experiments 1826)] .Sir James Hall on the Consolidation of the Strata. 803 in a manner fit to be laid before this Society. : This must be my apology to those who’ hear me, and to such of my friends as take an interest in these investigations, for having so long de- layed the publication of a set of facts, some of which had pre- sented themselves to my view many years ago. : Whoever, indeed, has had any experience in the prosecution of new subjects of experimental inquiry, knows that, owing to his ignorance of the requisite adjustment of the proportions of the ingredients, and of other similar arrangements, he must de« pend, in a great degree, upon chance for the success of his first results, and that he must often submit to spend much time and labour upon a subject, even after it has been made out to his own satisfaction, before he has acquired sufficient command over its details to answer for the result of any particular experi- ment, so as’ to be able to produce it with confidence to the public. | | nde It may be interesting, in the first place, to describe, in a general way, the geological structure of the country, in the neighbourhood of the singular scene which gave rise to these speculations. B Dis Ob fOU018 2 > On different occasions I have laid before this Society obser- vations made on the rugged shore which occupies the southern entrance of our estuary the Firth of Forth, which, from being frequently washed by a very boisterous ocean, eres to view a distinct exhibition of its internal structure. The eastern part is occupied by the promontory of Fastcastle, composed entireht of the elder quality of strata, called by the Germans Grey Wacke. Further to the west it consists of cliffs formed of Sandstone, nearly in a horizontal position. These two meeting in the crag called the Siccar Point, afford the most distinct view we any where have of the peculiar relation and mutual history of these two rocks. 3 | pot More inland, on the borders of Lammermuir, a set of hori- zontal beds occur, consisting of a loose assemblage of rounded. stones, intermixed with sand and gravel, which bear every ap- ‘pearance of having been deposited by water, and which, as to their general history, seem to have undergone no change since the overwhelming, though transient, agitations of water, of which | Thave frequently had occasion to speak in this Society. In the summer of 1812, as I was returning from visiting the granitic range which occurs in the water of Pastiet: in the hills of Lammermuir, and riding down the little valley of Aikengaw, -which deeply indents this loose collection of gravel and shingle, about two miles above the village of Oldhamstocks, and at the distance of eight or ten miles from the sea, I was struck with ‘astonishment on seeing one of these gravel banks, formed, as ~ (804 Sir James Haillion'the Consolidation of the Strata. [Ocv. above described, of perfectly loose’ materials, traversed. ‘ver- tically by a dyke, which, in its middle, consisted of whinstone, and was flanked by solid conglomerate ; but this solidity abated gradually till the conglutination of the rounded masses diminish- ing by degrees, the state of loose shingle and gravel was entirely restored on both-sides. The agglutinated mass:adjacent to the dyke bore no resemblance to the result of calcareous petrifac- “tion; scarcely ever gave effervescence with acid; and, by its gradual termination, differed from any whinstone-dyke I have seen to penetrate the strata; for, in the ordinary case, the ter- mination of the crystallite against the adjoining aggregate through which it passes, is almost always quite abrupt. | About a hundred yards higher up the valley of Aikengaw, there occurs an agglutination similar to the last; though without any whin-dyke, and sufficiently strong to resist the elements, by which the surrounding matters had been washed away, leavin the pudding-stone, or agglutinated shingle, to stand up by itself, in a manner ‘remarkable ‘enough to have attracted’ the notice of the peasantry as something supernatural,‘’since they. have bestowed upon it the name of the Pairy’s Castle. Farther up the stream, other agglutinations occur frequently, as we could see in little narrow glens cutting through the mass ; and higher still, they are so numerous as to meet and convert the whole into one unbroken mass of pudding-stone, occupying all that is exposed to view. ; These very remarkable, and, to me at least, novel appear- ances, were the first which suggested the idea, that the con- solidation not only of this class of conglomerates, but of sand- “stone in general, had been occasioned by the influence of some substance in a gaseous or aériform state, driven by heat into the interstices between the loose particles of sand and gravel, where it had acted as a flux on the contiguous parts. On considering what this penetrating substance might be, and from whence it could have come, the following circumstance presented itself to ‘my recollection at the moment, and promised to afford some assistance to these conjectures. + A few miles lower down the valley in which the above facts were observed, at the distance of more than a mile from the sea, and between two and three hundred feet perpendicularly above it, there occurs a crag of sandstone, in mek a numerous suc- cession of strata are distinctly visible. Several of these beds have yielded much to the action of the air, and, in dry weather, exhibit a considerable white efflorescence, which has completely the taste of common salt; and so remarkable is this circum- stance, that the rock has acquired, in the country, the name of Salt-Heugh. ts Here, then, it immediately occurred to me, was probably the 1826.] Sir James Hail on the Consolidation of the Strata, 305 source.of an abundant supply of the elastic substance or fumi- gator, whose action as a flux had been pointed out by the agglu- tinations in Aikengaw above described. | _I conceived, that, if there were at the bottom of the sea a bed of sand and gravel, drenched with brine of full saturation, and that heat were applied to it from beneath according to Dr. ~ Hutton’s hypothesis, the first effect would be, to drive the water from the lowest portion of the sand, and to convert the salt which remained amongst it, together with the sand, into a dry cake. During this operation, or until the cake became quite dry, the absorption of latent heat would prevent the temperature from surpassing the boiling point of brine. But no sooner was this dryness accomplished, than, I imagined, the temperature of the mass. would begin to rise above that, pitch ; the portion of it next the fire would gradually acquire a red-heat ; that then the salt, being made by the heat.in part to assume an elastic form, would be sent-in fumes through the dry cake just described, and thus, by partially melting the contiguous particles, produce an agglutination,’ . mae : ! : uch being my theoretical views, no time was lost in submit~ ting them to the test of experiment. ‘Taking it for granted that a quantity of sea-salt must frequently be formed and deposited, along with sand and gravel, at the bottom of the ocean (in the manner IJ shall have occasion to describe at another stage of this paper) where the water has been collected by its superior rN cific gravity, in the form of brine, I proceeded to make the fol- . lowing experiments. , : 7 _. Dry salt was placed along with sand, sometimes in a separate layer, at the bottom of the crucible, and sometimes .mixed throughout the experiment: the whole was then exposed to heat from, below. . I found that the salt was invariably sent in fumes through the loose mass, and by its action produced solid stone in a manner completely satisfactory, as illustrative of the facts in Aikengaw ;. and so.as to give a good explanation of the pro- duction of sand-stone in general. These artificial stones are of various degrees of durability and hardness ;—some of them do not stand exposure to the elements, and crumble when immersed in water ;—some resist exposure for years ;—others are so soft as not to preserve their form for any length of time;—while some bear to be dressed by the ‘chisel; and, it may be remarked generally, that, as far.as the results of my experiments have been compared with natural sandstone, the same boundless variety exists in both cases. A striking instance of this resemblance occurs in the case of the Salt-Heugh, the sandstone of which, when immersed in water, _ crumbles down, exactly in the same manner as those results of my experiments which taste much of salt. The fumes of the salt, no doubt, act, in all these cases, asa New Series, vou. X11. x 806 Sir James Hall on the Consolidation of the Strata. [Oocr. flux on the siliceous matter, and thus cement the adjacent par- ticles together. The Society are, doubtless, well aware of the power of salt fumes in glazing pottery; and the analogy, I con- ceive, is complete. It is the application alone thatis new, —__ So far the results were satisfactory. But it next occurred, that it might be plausibly objected, that the presence of the su- ache rea cool ocean would interfere with the process, on e principles of latent heat. To put this to the test, I pro- ceeded to expose a quantity of sand, covered to the depth of several inches with common salt-water, to the heat of a furnace, and, as the liquid boiled away, replenished it from time to time by additions from the sea. Of course it gradually approached to a state of brine, But this proved a very tedious operation, requiring a continued ebullition, during three weeks without ceasing, before it became sufficiently saturated with salt by the discharge of the fresh-water; and I thought it much easier, and no less satisfactory, to employ brine from the first, formed at once by loading the water with as much salt.as it could dis- solve, amounting to about one-third of its weight... — 3 ~ ‘The vessels employed in these early experiments were the large black-lead crucibles used by the brass-founders. . I filled the vessel, which was 18 inches high and 10 broad, nearly to the brim with brine of full saturation, the lower portion being oecu- pied, to the depth of about 15 inches, with loose sand from the sea-shore, and thoroughly drenched with the brine. In order to have a view of the progress of the experiment, I placed an earthen-ware tube, about the size and shape of a gun-barrel, closed at bottom, and open at the top, in a vertical position, having its lower extremity immersed in the sand, and reachi to within about an inch of the bottom of the pot, while the other end rose a foot above the surface of the brine, and could be looked into without inconvenience. uyyo1as . After a great number of experiments, eis an unbounded variety of results, I at length obtained a confirmation of the main object in view. I observed that the bottom of the porce- jain barrel, and of course the sand in which it rested, became red-hot, whilst the brine, which, during the experiment, had been constantly replenished from. a separate vessel, continued merely in astate of ebullition: the upper portion of the sand, drenched with the liquid, remained permanently quite loose, but the lower portion of the sand had formed itself into a solid cake. On allowing the whole to cool, after it had been exposed to a yee heat for many hours, and breaking up the mass, I was. delighted to find the result, occupying the lower part of the pot, possessed of all the qualities of a perfect sandstone, as may be seen in the specimens now presented to the Society.. Whenever the heat was not maintained so long, the sandstone which -re- 1826:] Sir'James Hall on the Consolidation of the Strata, 307 sulted was less perfect in its structure, tasted strongly of salt, and sometimes crumbled to sand when placed in water. Many of these early experiments were accomplished with tolerable success. But still the result was somewhat precarious, and could not be announced with the confidence that I felt in presenting my former experiments to this Society. _ The cause of this uncertainty I traced to the chemical ope- ration of the salt, acting as a flux upon the porcelain vessels employed. This very action, | was well aware, was the main agent and cause of our success, when kept within proper bounds; but, on being allowed to pass those limits, and to act on the containing vessel as well as on the experiment, it de- stroyed the vessel, and converted the whole into a confused mass of slag. : After numberless unsuccessful attempts, and after returning again and again to the charge, with an interval sometimes of years, 1 at last met with a quality in some of the materials to me altogether’ unlooked for, by means of which may be obtained successful results, with scarcely any risk of- failure. ’ I found that the action of the salt upon the substances of the erucibles of clay, did not exert itself in the same manner upon iron; but that a large vessel of cast-iron, 18 inches deep by 10 wide, and a common gun-barrel welded up at the breech, and open at the top, enabled me to work. with the heat of melting gold, without injuring the vessels, and at any time to produce a perfect freestone; thus satisfying our theoretical expectations. Similar results, in all respects, were produced by exposing pure pounded quartz to the action of the salt fumes,—and also when gravel, or any other mass of loose materials, was used ' instead of sand. nud ; Having now shown, in a satisfactory manner, that salt, whe- ther in a dry state mixed along with loose materials, or driven in fumes through them, or applied in the state of brine, and ex- posed to heat, is a sufficient agent to produce a consolidation, such as we see in natural sandstones and other stratified rocks, it remains to be investigated, whether an adequate supply of this flux may be reckoned upon in nature. | 7 It is well known that great diversity exists in the degree of saturation of the sea by salt, at different places ; and Buffon has been ‘at much pains in collecting ipstapiel of this diversity in his geological volumes, introductory to his Natural History. It is known that, in many of the communications between sea and sea, a constant current sets one way, indicating that the evapo- ration from the sea, to which this stream flows, surpasses in » quantity its supply of fresh-water from the rivers, rains, and springs. This is remarkably the case with the Mediterranean, into which a perpetual stream sets from the ocean, at the Gut of . x2 / 308 Sin James Hail on the Consolidation of the Strata. [Ocr. Gibraltar. We have reason, then, to conclude, both that the surface of the Mediterranean is Jower than that of the ocean, and likewise that the quantity of salt in the: former is perpe- tually on the increase ; so that the specific gravity of the waters, and the intensity of their saturation, must be perpetually ad- - vancing to a state.of brine. I am well aware, that an attempt has been made to render such a conclusion unnecessary, by the supposition of a :counter-current flowing at the bottom, out of this great basin; but such suppositions are,in my Opinion, alto- ‘gether gratuitous... ta ii hat is here said of the Mediterranean, will apply no Jess to -other seas, and even to the greatoceans. And wherever a basin occurs, in which a bottom of great depth is surrounded by a ridge comparatively shallow, we may expect to find the lower portion, at least, of the water in a state approaching to brine. Without any such theoretical explanation of the manner in which a supply of salt is supposed to be formed, it may perhaps be considered sufficient for my purpose, to recal to the recollec- tion of the Society, that there are in almost. every, part of the ‘world vast districts of rock-salt, and in some countries extensive salt lakes and salt rivers; and in our own country we have many instances of brine springs, besides rock-salt in abundance, Here then it seems to me, we are plentifully furnished with the means of accounting, in the manner experimentally shown, for the agglutinations of such gravel as that of Aikengaw and for the strata of the Salt-Heugh, which, by an easy analogy, may be transferred to sandstone.in general, and, perhaps, to stratified rocks of every description. he Ns A member of this Society, however, well known by his scien- tific acuteness, alleged, first in his public lectures, and after- wards, upon my requesting an explanation of his objection, again repeated, that I was not justified in such, theoretical conclusions, respecting the influence of heat at the bottom of the sea, since the neighbourhood of the coo) water would neces- sarily counteract that influence. pian 1 haw In answer to.this difficulty, I must beg leave to remark, that, in all my experiments above alluded to, the sand. (viewed by means of the gun-barrel) was seen to. become red-hot during the ‘process of consolidation, while the superincumbent brine remained boiling above ; and it was even found.easy, by supply- ing cool brine in sufficient quantity, to maintain the temperature of the fluid permanently such, that the hand,could be. plunged into it at. top, without injury, the sandstone below remaining all the while at afullred heat, But whenever I repeated this expe- riment, with every circumstance the same, both, as to duration and temperature, as in the example above detailed, but in which, instead, of brine, fresh. water .was used, the .result was very. different, » The lower part.of the gun-barrel, immersed. in .the 1826.] Sir James Hall onthe Consolidation of the Strata. 309: sand, and) in which gold had melted in the brine experiment just mentioned, now remained permanently. black, and. cold ; and the whole of the sand in the pot, when removed from the furnace, fell out loose by its own weight ; not’ the least trace of consolidation having taken place. 0998 We may thus, I trust, presume to have added one more new and important modifying circumstance of heat, to those already, advanced in support of the Huttonian, doctrines; for, sincé it has been experimentally shown, that heat, under the modifica- tions produced by the presence of salt, as above-described, is fully adequate to the consolidation of loose materials, exposed to its action, it may fairly be presumed, that salt has performed. a part, and a very important part, in the consolidation of the strata of the globe. | : | I should be doing injustice to the subject, were I not to state, that, besides the views developed in the foregoing paper, and supported by actual experiment, many others have occurred to me, respecting the agency of salt.under various modifications, and all bearing more or less directly upon the Huttonian Theory of the Earth. Some of these views have been submitted to the test of experiment, and the results, as far as they have yet been carried, give me great hopes of ultimate success. Others are still in the shape of mere conjecture; and none of them are yet in a state to lay before the Society in detail. A simple allusion to one or two of the most important of these views may probably be received with indulgence; and I shall be very happy if gentlemen possessed of adequate leisure shall be induced. to follow up, by actual experiment, what I have thrown out. as mere matter of speculation. , I conceive that salt, in the state of fumes, and urged by a powerful heat, possibly also modified by pressure, or perhaps combined with other substances, may have penetrated a great variety of rocks, acting as a flux on some, as in basalt, granite, &c.; agglutinating others, as in the case of sandstone, pudding- stone, Xc.; softening others, as in the case of contorted strata of greywacke. In many cases, too, I conceive that these fumes may have had the power of carrying along with them various other materials, such as metals in a sublimed state, which would in this way be introduced into rents, veins, and cavities, or may even have entered into the solid mass ‘of the rocks, which I imagine these fumes may have had power to penetrate. I have already tried some experiments in pursuit of these ideas. Salt, for instance, has been mixed with oxide of iron, reduced to fine owder} and then exposed to heat along with quartzose sand, he iron, I found, was borne up along with the salt fumes. The sandstone, formed in this way, was deeply stained with iron, and other most curious appearances presented themselves, Every one who has seen a sandstone quarry must have noticed \ 310 Sir James Hall on the Consolidation of the Strata. [Oet. evident traces of iron, the rock being stained in a great variety of ways ; sometimes in parallel layers,—sometimes in concentric circles, or rather in portions of concentric spheres, like the coats of an onion,—and, generally speaking, disposed in a way not accountable by deposition from water. All these appearances 1 would account for, by supposing the rock, either at the moment of its agglutination into sandstone, or at some subsequent period, to have been penetrated by the fumes of salt, charged with iron, also in a state of vapour. : I may mention one very curious result of my experiments with salt and iron, acting upon sand, namely, that, upon break- ing up the specimen of artificial sandstone, an appearance often presents itself of incipient crystallization, if 1 may use’ this term ; a number of large, shining, parallel faces pervade’ the whole mass, and, by holding the specimen at the a le to the light, this appearance becomes very obvious. What the nature of these crystals is, I have not investigated; but as they very much resemble what we see in different kinds of sandstone, 1 am of opinion that they hold out a fair expectation, of our being able to Pegtes many of the crystalline appearances with which we are familiar in nature. Common sea-salt, such as I have used, as is well known, is not pure muriate of soda; and, in my experiments, | have mixed various Other substances with it. In Nature, we must suppose that various contaminating substances would in like mamner occur, to diversify the phenomena; and, accordingly, we do find a boundless variety, in the aspect not only of sandstone, but of almost every kind of rock; and I am by no means with- out expectation, that, in the course of time, we shall be able to imitate in our laboratory as many of these varieties‘as we choose to exhibit. : I have long been engaged also in a series of eee on the formation of Crystallites, the hame by which, as I have before stated, every crystallized rock might, perhaps, be usefully distinguished in contradistinction to Aggregates, or those formed of fragments. This great object in experimental geology, I hope to accomplish by means of an instrument which I have Jong had in use, for the regulation of high heats, a description of which may probably soon be laid before the Society, together with some further results in support of the Huttonian Theory of 1826.] Scientific Notices—Chemistry. 3it Arricte VII. _ SCIENTIFIC NOTICES. CHEMISTRY. : 1, Muride, a supposed new elementary Substance. On the 3d of July last, M. Berard read to the Parisian Aca- demy of Sciences a memoir by M. Ballart, of Montpellier, in which he announces the discovery of a new elementaty sub« stance, which he denominates muride. The memoir was re ferred for examination to M. M. Vauquelin, Thenard, and Gay Lussac ; but the following is a sketch of its contents. =” In. its wncombined state, muride is a reddish liquid, with an odour resembling that of chlorine ; its specific gravity is 2°966, it is volatile, and boils at 117° Fahr. At a pressure of 76 cent. it gives a red vapour resembling nitrous gas. It remains fluid at 14° Fah. ; is soluble in water, alcohol, and ether; is not altered by a red heat, or by the electric current, extinguishes burning bodies which are immersed in its vapour, decolorizes indigo, and com- bines with most of the simple bodies, forming compounds analo- gous to those produced by chlorine and iodine under the same ciréumstances. It combines with nascent hydrogen, losing its colour, and acquiring the properties of an acid, termed by M. Ballart hydromuridic acid. This acid is readily decomposed by chlorine, which unites with the hydrogen, and liberates the mutide in the form of red vapours. It 1s not decomposed by iodine, but on the contrary decomposes hydriodic gas, and sepa- rates the iodine. Hydromuridic acid is not decomposed by oxygen. Potassium, zinc, iron, tin, and other metals, decompose it, disengaging the hydrogen, and uniting with the muride ; the resulting compounds are in every respect analogous to chlorides. The muridure of potassium has the cubic form, like the iodide and. the chloride of this metal. _ M. Ballart mentions several processes for obtaining this sub- stance. One of them is as follows: He passes a certain quantity of chlorine into the mother-water of salt-pans, which decomposes the combined hydromuridic acid it contains, the muride in solution giving the fluidared colour. This solution is thenagitated with ether, which dissolves the muride, and by the addition of caustic potash, a muridure of potassium is formed, which is easily sepa- rated in the solid form: this combination is decomposed in the sequel by means of sulphuric acid and oxide of manganese. The operation is performed in a glass retort, to which is adapted a horizontal tube containing chloride of calcium, and to this tube is adapted a smaller one immersed in a receiver properl cooled. The muride is to be kept in a ground-stoppered bottle, with a small quantity of common sulphuric acid, which, being lighter than the muride, floats upon it, and prevents its evapo- ration.—(Journal de Pharmicie.) 312s Scientific’ NoticesMirieralogy, [Oer. 2. Spontaneous Combustion of Chlorine and Olefiant Gas. It has long been known that chlorine and hydrogen in mixture are liable to explode, when struck by the direct rays of the sun, and an instance is related in the American Journal, (vol. iii. p.341,) in which these two gases exploded, even im. the diffuse light of a cloudy and snowy day. I have not met with any account of a similar action on the part of chlorine and olefiant or heavy carburetted hydrogen. It is well known that when mingled, in about equal volumes, they combine quietly, and become con- . densed into the peculiar aromatic, oily-looking substance, since ealled chloric ether. This effect I had so often witnessed, and had never seen any material variation in the result, that I was not prepared to look for any thing else. But. in an experiment of this kind, (January 5, 1826,) happening to. mingle the. chlo-. rine with the olefiant gas in such a manner, that the latter gas was uppermost, the combination went on more slowly than when. the reverse order was observed ; and the oily matter was gra- dually precipitated, but was. less abundant in quantity than usual. Repeating the experiment, in the same manner, the gases had remained in contact a few minutes, apparently with-, out mingling much except at their surfaces—the chlorine pre- serving its peculiar colour and the other gas its colourless trans- parency, when, suddenly, a bright flash pervaded the bell-glass, ' which was of the capacity of five or six quarts ; it was raised. . out of the water with a slight report—a dense deposit of char- coal lined the glass and floated on the water of the cistern, and. the chlorine disappeared. The appearances were much like. those which are exhibited when a rag dipped in oil of -turpen-. tine is placed in a jar of chlorine gas. , Reflecting on the circumstances, | was led to believe that the: eculiar effect, in this case, arose from the fact, that, owing to the great difference in the specific gravity of the two gases, the action took place principally at the two surfaces of contact, and, thus the chlorine acting upon a comparatively thin ‘stratum of. inflammable gas, the two became so heated, as to pass into vivid, combustion. Every new occurrence in practical chemistry, which may involve danger, ought to be exactly stated, that. we. may be aware of contingencies not otherwise anticipated.-—. (American Journal of Science.) oe | MINERALOGY. 3. Thenardite. This substance was discovered in the Salt Works of Esper- tines, about five leagues from Madrid, by M. Rodas, a Spanish manufacturer. The crystalline form is described by M. Cordier, d the analysis is by M, Casaseca, Professor of Chemistry at 1826.] Scientific Notices—Mineralogy. $13 Madrid, and a pupil of M. Thenard, in honour of whom he has named it. LOG The forms of the crystals are easily ascertainable, but the planes are too uneven to admit of accurate measurement ; the planes obtained by fracture are, however, even, and the primary form of the crystal is determinable with considerable accuracy ; the cleavage is threefold, and in one direction the lamine are perfectly smooth and brilliant. The primary form (fig. 1), indi- cated by cleavage, is a right prism with a rhombic base, the angles of which ‘are nearly 125° and 55°; taking the mean of several measurements, the height of the lateral planes is to that. — of the terminal as 13 to 15; the cleavage is most distinct in the: direction of the base. | ! There are two varieties of the crystal; first, the octahedron, (fig. 2). . It is formed by a decrement of two rows of molecules in height, on the edges of the bases of the primary prism. The octahedron is symmetrical, and very flat in the direction of the. small diagonal of the bases of the primary prism. _ Its vertical section in the direction of the greater diagonal of the base is a slightly acute rhomb, the smaller angle of which coincides with the: summit of the crystal. he The second variety (fig. 3) is the preceding crystal, with the summits replaced by a rhombic plane parallel to the bases of the: primary form. | ee The crystals would probably be doubly refractive, but they are not sufficiently transparent to admit of this point. being determined. .The specific gravity is nearly the same as that of glauberite, viz. about 2°73. | rad The chemical characters of the crystals are, that, when exposed to the air, they become opaque, and the surface is covered with a powder which is readily removed. According, however, to M. Casaseca, this is not owing to the loss of water, but to the, absorption of a small quantity, for the salt is perfectly anhydrous,. losing scarcely any weight by exposure to a strong heat; and this little is probably derived from the slight efflorescence at the surface. already noticed. Thenardite is perfectly soluble in» ° water ;. the solution when saturated is slightly alkaline.. When ut into dilute sulphuric acid, it effervesces, owing tothe evo- ution of.carbonic acid gas. Examined. by the usual re-agents, 314 Scientific Notices——Miscellanéoiis. [Ocr. it ray to contain only sulphaté and carbonate of soda, and in the following proportions : ey | ti beat Sulphate of soda ...... sale (Anis meena Carbonate of soda. ..s.esseccecssen Orde. eiars rOrOr ea (Journal de Pharmacie.) _ MiscELLANEOows. 4. Remarks on Bowlders. By Peter Dobson. I have had occasion to dig up a great number of bowlders, of red sandstone, and of the conglomerate kind, in erecting a cot- ton manufactory ; and it was not uncommon to find them worn smooth on the under side, as if done by their having been dragged over rocks and gravelly earth, in one steady position. On’ examination, they exhibit scratches and furrows on the abraded part ; and if among the minerals composing the rock, there happened to be pebbles of felspar, or quartz, (which was not uncommon,) they usually appeared not to be worn so much as the rest of the stone, preserving their more tender parts in a ridge, extending some inches.. When several of these pebbles happen to be in one block, the preserved ridges were on the same side of the pebbles, so that it is easy to determine which part of the stone moved forward, in the act of wearing., I have caused blocks, with the above appearances, and weighing 15 tons, to be split up; arid there are now a number of good specimens about the place, that will weigh from 10 to 50 cwt., dug out of the earth 200 feet above the'stream of water in the ee HOD! | | These bowlders are found, not only on the surface, but I have discovered them a number of feet deep, in the earth, in the hard pound of clay, sand, and gravel, - One block of more than 380 cwt., marked and worn as above described, was dug out of a well, at the depth of 24 feet; a part of which is still to be seen. Bowlders, with these marks upon them, I have observed, not only in this town, but in Manchester, Ellington, and Wilbraham. I think we cannot account for these appearances, unless we call in the aid of ice along with water, and that they have been worn by being suspended and carried in ice, over rocks ‘and earth, under water. | | | It is stated in the Edinburgh Encyclopedia, vol. xiii. p. 426, that “ fields of ice sometimes rise from the bottom, and bring with them masses of rock, of several hundred tons weight. These masses of stone are imbedded in the ice, they are carried along with the ice, and deposited on shores at a great distance from their original situation,” | 4826] Scientific Notices—Miscellancous. 315 Similarideas:are.expressed in the same work, vol. xi. p..70. - I mention these appearances on bowlders of sandstone in this vicinity, in order that im other places, if similar appearances exist, they may be noticed. Such observations, may lead to probable coriclusions respecting the transportation of bowlders, and the formation of banks of earth.—(American Journal of Science.) | 5, New Species of Salamander, (inhabiting Pennsylvania.) By _ Richard Harlan, M.D. Prof. of Comp. Anat. to the Phil. _ Mus. , | S. flavissima. ». Char... Brownish, yellow above ; clear bright yellow beneath ; ‘beak marked with three black lines; tail compressed, longer than the body. , you iia hee « Dimensions. Total length three inches two tenths; length of the tail one inch nine tenths; of the body, head inclusive, one inch three tenths. baci Description... A. long and slender animal, head broader than the body, rather depressed ; eyes prominent, iris gilt yellow ; a broad black. line on each side of the spine extending from the eye to the. end of the tail; a marrow depressed black line ex- tending along the spine from the occiput to the base of the tail ; all the under parts of the animal of a deep yellow; head separated from the neck by a transverse line under the throat ; tail compressed, much longer than the body and. head. Note... I have caught several of these animals beneath the stones in moist places, or on the borders of brooks in shady situations ; it is a very active species and sometimes attains to three inches in total length ; the black line in the dorsal furrow is sometimes wanting, in which case the back is mottled with black—placed in spirits the yellow colour is destroyed. This species will occupy an intermediate station between the S. bis- lineata and S., a, RE, A specimen is in the cabinet. of the Acad. of Nat. Sc. of Phil—(American Journal of Science.) 6. On the Semi-decussation of the Optic Nerves. : By Dr. Crawford. Mrs. B. at 65, had a slight hemiplegic attack of the left side, 9th Dec. 1816. She regained in great meesure the use of her limbs ; but the following affection of the sight continued from the ay of her seizure till her death, about five years after- wards. When she looked at any object, she could only see one-half of it distinctly, the other being very obscure. For example, in looking at a person’s face, she could only see distinctly that side ef it which was to her right hand. This was equally the case whether she looked with both eyes, or only with the right one 3: 316 New Séientific Books. [Ocr. but when she looked with her left eye only, the obscurity was ater. When four fingers were held before her, she could see two of them distinctly; the third she could distinguish, but could not see plainly; the fourth she could mot see at all. When she looked at three fingers, she could see two of them pretty plainly; the first, however, more than the second, and the third she could not distinguish at all. When she looked at two fingers, she could only see one distinctly... fter she had recovered so as to be able to get out of bed, it was discovered that, although she could only see one-half of an abject Leary 6 when held directly before her, yet, if it was moved to her right hand, and she continued to look straight forward, she could see the whole of it distinctly. On the contrary, if it was moved to her left hand, keeping her eyes fixed -as ‘before, she could not perceive any of the object at all, Dr. Wollaston does not notice this last circumstance in the instances he relates ; but it appears to me an additional confirm- atien of his opinion. The defective vision was owing to the insensibility of one-half of the retina of cach eye; and that was occasioned in this instance, probably, by pressure on the right tha- lamus nervi optici, where the nervous fibres thence proceeding (on the supposition of this semi-decussation with those from the left - thalamus), finally expand into the right half of the retina of each eye. This part of the retina being insensible, the rays of light which passed to it from nf on the left of the centre of vision, roduced-no sensation. But when the eyes were kept fixed, and the object to be looked at moved to the right of the centre of vision, so that all the rays from it passed to the left and sound shalf of the retina, then the whole of the object became visible. It should be remarked, that, although the sensation of only the /eft side of the body was impaired, yet it was the right half of each retina which was insensible—(London Med. and: Phys. Journ.} Winehester, Nov. 5, 1824. Arrticte VIII. NEW SCIENTIFIC BOOKS. e: PREPARING FOR PUBLICATION, : : Mr. W.. Phillips will shortly publish a new and improved Edition of his Outlines of Mineralogy and Geology, for the use of young persons.. The Fluxional Calculus; an Elementary Treatise designed for Students ofthe Universities, and for all those who desireto be acquainted with the principles of analysis; by T. Jephson, BD. vers Lectures on Astronomy, accompanied and illustrated by the Astronomicon, or a Series of moveable Diagrams. By W. H. Prior. Travels of the Russian Mission through Mongolia to China, By G. Timkowski; with notes by M, J, Klaproth, 2 vols. 8vo, - 1826. Aosreto by Met Batata oD. 317 JUST PUBLISHED, Koecker’s Principles of Dental Surgery: 8vo. 14s. Scratchley’s London Dissector. 6s. Fife’s Manual of Chemistry. _ 7s. fe, ie _Samouelle’s Directions for preserving Insects. 5s. ‘’Morison’s Outlines of Lectures on Mental Diseases. 10s. igi Rough Notes across the Pampas and Andes; by Capt. J. R. Head. 9s, 6d. ~ ArtTIcLE TX. NEW PATENTS. Count A, Eugene de Rosen, of Princes’-street, Cavendish-square, for anew engine for;communicating power to answer the purposes of a steam-engine.—Aug.1, | . | | bes J. B. Wilks, Tandridge Hall, Surrey, for improvements in producing steam for steam-engines, and other purposes.— Aug. 2. L. W. Wright, Wardugh-idad, engineer, for improvements in the: construction of trucks or carriages, applicable to useful purposes.— Alig. 22 2°. J. Williams; ironmonger and ships’-hearth manufacturer,‘ and J. Doyle, mechanist, Commercial-road, for an apparatus and process for separating salt from sea-water, and thereby rendering it fresh. and fit for use.— Aug. 4. E. Hazard, Norfolk-street, engineer, for methods of preparing — explosive mixtures, and employing them as a moving power for machinery.—Aug. 12. ) :: 873-6292 : 7:8808 specific gravity. And 873°6292 x 7:8808 = 6884-8970 the pendulum heavier than air. Square of the number of vibrations 86158-674 = 7423317105, 4383 divided by 68848970 = 1078203°073 x the square.of the number of vibrations in 24 hours, and the square root:of the same, gives the number of vibrations in 24 hours, corrected for the buoyancy of the atmosphere = 86164-931 or 4+ 6:257 vibra- tions for the correction. . In like manner, the corrections for the buoyancy of the atmo- sphere were found for the other sets (L), and are for the second set + 6254; for the third + 6°333; and for the fourth + 6:269. | ‘ The corrected number of vibrations in 24 hours will, therefore, be; first set 86164:931; second 86165:966; third 86167°111 ; fourth 86167-233. . Following the same process with the results (R), we shall have the correction on account of the buoyancy of the atmo-- sphere for the first set 62892 ;. for the second 6°2685; for the third 6°3486 ; and for the fourth 62759. | And the corrected number of vibrations; first set 86165°0772; second 86165°9115; third 86167-3836; and the. fourth 86167:3659. | It now only remains to ascertain and apply the correction for - the height of the pendulum above the level of the sea. The 348 Mr. Goldingham’s Report) (Nov. height. of the pendulum above the level of the sea at low water was 124 feet, or.0:00236742 of a mile; the radius of the earth at the equator being allowed 3967-5 miles... Hence the :correction for the height of ‘the pendulum above the level of the sea will be + 0°0514 of a vibration.» . The true number of vibrations in Od os will, therefore, be 3 First set (1). set enseeeeceesereccseseeces 001049822 Second. . sesttcoritatnasientsneanints ne 861660177 Priest to.c4 + watine stb ebvoMy bid 65 t8at . 861671624 FOUrtiNs, 3 0%.1 cd0.0.5.) 4.0,br ant PR _ . 86167-2848 First sot (Ry. ie Sy 4, at gh AROSE OFIRA ee -Antor tat WECONIG. vec tis bo ks cue Stree PL e pocket aber es TOU oUse Third”. srt eo Aw? 19 NGL 20 FX, woes 86167-4350 MOURN: oa Pace cece aces UR EPO ey ARO . 86167-4173 In London, latitude 51° 31’ 8-4”, the rie te of experiment | made 86293°14 vibrations in 24 ‘hours, the thermometer bein 67:6, and the barometer 29°97 inches ; the height above the cat of the sea 83 feet. Hence the correction for the buoyancy of the atmosphere, allowing the Mint specific gravity, will be + 6°7478; and that for the height above the sea + 0-22: the true number. of vibrations in 24 hours will, therefore, be 86300-1078, the square of which is 7447708606: 2916. The length of the seconds pendulum in London at the tem- perature, of 70°, deduced from Cape Kater’s experiments, ‘is 39+142434 inches. Now 86300-1078? : 864002 :: 39:142434. : 3923310101 inches, the length of the endulum of experiment. Then by the first set d) 864002 : 86164-9822 :: 39'23310101 : 39°0199543268 the length of the pendulum at Gaunsah Louts.: prs same operation, the length of the pendulum at Gaun- sah Lout by the-second set (L) is 39:0208915108; by the third 39: 0219289661 ; by the fourth 39:0220398271 inches: Repeating the operation, the first set (R) gives the length of the pendulum.at Gaunsah Lout 39:0200869218; the second 39°0208425551 ; the third 39: URI BOO and. the fourth set 39:02215983605 inches. ‘The mean of these will be: First...... 39:0199543268 Second... 39:0208915108 ° aMdames 200d tan dx Seatale eve pines Third. .... 39°0219289661 Fourth ..., 39°0220398271 39-0219843966 Mean of the four sets. . 39°0212036577 Sets (L)< 1826.] of the Length of the Pendulum at the Equator. 349 _ Also, | va : ( First ...... 39°0200869218 . Second. .. 39°0208425551 — | Mean...2.... eee e+e 39°020464738 Sets(R){ | Third. .... 39 0221758674 Fourth .... 39°02215983605 i Mean......66+++4++39°0221678517 Mean of the four sets (R)39-0213162951 Mean of the foursets (L)39-0212036577 Length of the pendulum at Pulo Gaunsah Lout by the mean of all the experiments, 39°0212599764 inches. The latitude of Palo Gaunsah Lout, according to the mean of the meridian observations, as. hereafter deduced, is 0° 1’ 48°78” north. Then by combining the London observations and those at ‘Gaunsah Lout, we have the length of the pendulum at the Equator 39: 02125994 inches. We now proceed to deduce the length of the pendulum at Madras by the specific gravity found at the Mint. | During the time of taking the first series of experiments at Madras, the mean height of the thermometer was 83°48°, of the barometer 30: 121, the number of vibrations in 24 hours 86166-108. Hence we find that the correction for the buoyancy of the atmosphere i is + 6-376. The mean height of the ther- mometer during the time of taking the second series was 85°49°, of the barometer 30-258, the number of vibrations in 24 hours '86166: 048; and the’ correction now deduced for the buoyancy of the atmosphere, + 6°378. The correction for the _ height above the level of the sea, as formerly found, is + 0:095. These corrections being applied, we shall find the true number of vibrations in 24 hours by the first series 86172°579 ; and by the second series 86172°521; the mean being 86172: 550. Hence the length of the ‘pendulum at the Madras Observa- tory, in latitude 13° 4’ 9:1” north, by the first series, will be 390268350769 ; and by the second series 39:0267825415 ; the mean of both being 39:0268088092 inches. / Then by combining the London with the Madras experiments, and taking the lene +f of the pendulum at the Equator, deduced from the Gunga te out etneniments'* we find the diminution of gravity from the Pole to oe Equator to be °0052756159 ; and the ellipticity of the earth —— sar seams * The length of the pendulum at the Equator by computation, with the data here given, will be 39°01628254 inches; differing from the measurement 0°00497740 of an inch ; the diminution of gravity from the Pole to the Equator, using the computed length of the pendulum will be -00527629, and the ellipticity of the earth =~ 50657" ! [Nov. 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Referring to the extracts from Sir Stamford Raffles’ letter’ before given, we find only the geographical situation of Bencoo- len, et that of two or three other points to the southward, are supposed to be rb a | known ; and even Bencoolen, accord- ing to the latest and best authorities, appears to be placed | upwards of twelvé miles more to the eastward than it aly is, supposing the longitude here deduced to be correct, which there seems little reason to doubt. Proceeding to the northward, we find Natal is considered to be in longitude 98° 40’ E; whereas, according to the foregoing deductions, it is in longitude 99°12’; so that between Bencoolen and Natal, in a difference of latitude of little more than four degrees, there appears to be an error in longitude of about 34 minutes. Mount Ophir, according toa: chart of Arrowsmith’s, published ten or eleven years ago, is placed in about longitude 100° 12’, which is more than eleven. miles too far to the eastward ; Natal is in 99° 24’, or 44 east of . the authorities before alluded to, and about 22 miles east of the longitude deduced from the observations given in this report. Frémn all which it will appear, I imagine, that the geographical situations here deduced are of considerable value ; and, as was. intended, will furnish points of departure for a survey of the. coast and islands, as well as for navigators, who, with good. chronometers on board, may do much towards filling up with. accuracy between the points now given, the greatest difficulty . being to establish a position to take a departure from. Bencoo-_ len and Mount Ophir are two excellent points; the other prin-. cipal places here given are not much inferior. Pulo Gaunsah - Lout, if navigators could discover it, would also be among the best places for taking a departure from, its position being also so well laid down. : Madras Observatory, Re J. Gotpincuam, Astron. . Artic.e VI. On Cafein. By M. Pelletier.* Ir is well known that a white volatile crystallizable substatice exists in coffee: the discovery was made y M. Robiquet, and stated in his analysis of coffee, read in 1821 to the Society of | Pharmacy. At the same period M. Caventou and I, without “ knowledge of the labours of M. Robiquet, also found this substance in ascertaining whether coffee did not contain quina or some analogous substance, coffee being similar to cinchona in the natural method, M. Robiquet has stated this fact in his memoir. * Journal de Pharmacie. 1826.) M. Pelletier. on Cafein. B55 Hitherto but little is known’ about cafein, M. Robiquet not having published his memoir upon it, and we were waiting its publication in order to state some observations which had been made by us only.* | ae some time:since had occasion to prepare a quantity of cafein, | employed a process which appeared to combine several advantages, and ‘this, I think it proper to publish, more especially because I had, rather from analogy than certain proof, hazarded the opinion, ih opposition to that of M. Robiquet’s, that cafein is alkaline; and I have since satisfied myself that with acids it acts similarly to those substances which are electro- . chemically indifferent, andthat’when it dissolves in acids, the solution takes place like that of narcotin for example, that is, without saturating the acid, and very differently from morphia, - | &e.; and I, therefore, take advantage of this opportunity to state what appears to me to be fact in this respect. M. Robiquet obtains cafein by treating raw coffee with cold distilled water; the brownish liquors are evaporated after being treated with calcined magnesia; and then being suffered to remain, the cafein crystallizes in nearly colourless semitransparent arborescent crystals. It is purified by solution in alcohol or | boiling water, from which it separates on cooling in silky crys- tals resembling amianthus. The process adopted by M.Caventou and myself is rather different: we exhaust the raw coffee by alcohol, the spirituous extract is afterwards. treated by cold water which separates a fatty matter; the solution of the extractive matter is heated with the addition of caustic mag- nesia; the magnesian precipitate collected in a filter is slightly — washed and treated with alcohol to separate the cafein, which is separated by evaporating the alcohol. A difficulty occurs in the evaporation if the magnesian preci- pitate is insufficiently washed, and the cafein extracted by the alcohol is rendered impure by the presence of adventitious colouring substances resembling syrup; and from these it is very difficult to purify it without incurring great loss; on the other hand, if the precipitat¢ is well washed, very little cafein 1s obtained, it being carried off by the washing water. It is indeed true, that by concentrating the washings and putting them in a cold place, crystals of cafein may be procured ; but this does not always succeed, especially in summer, owing to the fermentation which takes place in the liquors. It is to avoid this inconvenience that I have sought for an expeditious method of separating the cafein from the washing water. I wash the magnesian precipitate perfectly to dissolve the whole of the * An extract of M. Robiquet’s memoir will be found in the Dictionnaire Technolo- guique, Article Cafe; and of ours in the Dictionnaire de Medicine. ; 2 th 2 356 M. Pelletier on Cafein. _ ‘ENov. cafein, and then evaporate all the liquors to obtdin a dry extract, using a salt-water bath towards the end’ of the evapora- tion ; 1 then treat the extract with alcohol: of sp. gr. 817; this dissolves the cafein without taking up any sensible quantity of the saccharine and gummy coleuring matter. In order to extract the whole of the cafein, the extract must be treated five or six times with alcohol, taking care to dry it by steam, or a salt- water bath, before each addition of fresh alcohol. | The spirituous solutions filtered through purified animal charcoal are to be concentrated by distillation to a certain point, and then very fire crystals of cafein are obtained. Having procured by this process a very considerable quantit of cafein, even from some much damaged coffee which my col- league, M. Henry, had sent me, I lied an opportunity of deter- mining whether cafein saturated acids, and whether, as I:at first thought, it ought to be regarded as a salifiable organic base. I was soon convinced that this substance possessed no electro- chemical property. Acids increase its solubility but little in cold water, in which it is but slightly soluble, but by hot water — it is readily taken up. The circumstance which led me into an error was this; I obtained) some crystals, in the form of long transparent prisms from the acid liquors, whilst from pure water I procured only a confused crystallization of opaque silky ‘threads; whether acid be present or not, weak solutions. give long, acicular, transparent, and slightly flexible crystals; but whatever quantity of acid and cafein be mixed, the acidity of the liquor depends upon the relative gr onsen of water and acid, and it is not sensibly diminished by the cafein. | I shall not now state the other properties of cafein, referring for them to the Dictionnaires de Technologie et de Medicine, already mentioned, I have only noticed the action of acids to correct an error which I had committed. Returning to the process for extracting cafein, it may be inquired, why, as this substance is not alkaline, magnesia is employed to obtain it? The magnesia appears to me to favour the operation on account of its affinity for colouring matter. Having several times endeavoured to do without it, [ have indeed obtained cafein, but in much smaller quantity, and as it was very impure, much.of it was lost by partying it. I have no doubt, ~ but that by employing acetate of lead, or any other substance, which would separate the colouring matter, the same results would be obtained; but the ate which | have detailed. appears to me to be more simple than those which it would be necessary to follow in making use of metallic salts. According to the analysis which M. Dumas and I have made of cafein, it is of all, vegetable products that which contains 1826.] Account of an improved Electro-magnetic Apparatus. 357 most azote,* and more than animal bodies; nevertheless it does ‘not, under any circumstances, undergo the + wet ferment- ation, which seems to indicate that the difference which exists between azotized vegetable and animal matter, the putrefying property which the latter possesses does not depend upon the greater quantity of azote, but upon a peculiar’ arrangement of the compound molecules; crystalline force alone might suffice to preserve this stability of the elements in cafein and some ‘ other azotized products of the vegetable kingdom. Even in animal substances, it may be observed that those which crys- tallize, such as urea and uric acid, though much azotized, are the least susceptible of putrifying. : ArticLE VII. oaipulpis of an improved Electro-magnetic Apparatus. ) f By Mr. W. Sturgeon.+ | Tue science of electro-magnetism, although so generally interesting, yet (comparatively speaking) appears to be very little understood. This latter circumstance is probably, in a great measure, owing to the difficulty of making the experi- ments, and the great expense attending the process;. for, besides the first price of a large battery, considerable expense in acid must always attend its excitation, whenever an experi- ment is attempted. Large batteries are always attended with difficulty of management, and the great quantity of hydrogen evolved during the process renders the use of them extremely inconvenient to the operator. These are evidently great obsta- cles to the experiments being often repeated; and to the science being generally known. Another, and perhaps no less obstacle to the advancement of this interesting science, is, that the expe- riments Seng hitherto exhibited on so small a scale, are by no means calculated to illustrate the subject in public lectures ; for when the experimenter succeeds even to his wishes (which is not frequently the case), the experiment can only be seen by a very near observer, and the more distant part of the auditory are obliged to take for granted what they hear reported (from * Cafein is composed of Carbon. iis eiscds - 46°51 | Albumen contains of azote 15°705 PAINE oc aiveg oni & 6 21°54 | Gelatine........-. tee lme'e 16-998 Hydrogen ....... “MOR | BID scccsce ce ctecccste 19°934 Oxygen......0-. 2T:14)| Urea ies eek 43°400 100-00 py then contains. less azote than urea only, and urea putrifies ‘less readily than rin, &c. t Abstracted from the Transactions of the Society for the Encouragement of Arts, &¢. 358 Mr. Sturgeon’s Account of ' [Nov. those persons who are more favourably situated), of some of the most. interesting facts, which they, from their distance, are unable to witness. | With a view of removing, in some measure, these apparentl formidable obstacles in the progress of this infant science, have devoted a considerable ' Aeag of time, labour, and expense, in repeating several of the experiments, under various circumstances, and with various forms and sizes of batteries, I have likewise instituted a series of experiments, for the purpose of discovering, if possible, if any particular ratio of galvanic and magnetic pare was absolutely necessary to be observed in the process of electro-magnetism, If no particular proportion of those two powers was essential, then it appeared highly probable that an increase of magnetic power might compensate for a mat ce | of the galvanic, and ¢hereby render the use of large galvanic batteries quite unnecessary, an object which I consi- dered both interesting in its. nature, ay by reducing the expense, and nou the process, exceedingly desirable to the experimenter; and I am happy to state, that my labours were no ways abortive, for instead of electro-magnetic pheno- mena depending on powerful galvanic, and feeble magnetic force, as had till then been practised, I found, during that inquiry, that the galvanic force may be reduced to almost an degree, provided the magnetic be sufficiently powerful. This discoyery led me to the use of powerful magnets, and small galvanic batteries, for with small magnets the experiments can never be made on a large scale, although the galvanic force be ever so powerful ; and as minute and delicate experiments are not calculated for sufficiently conspicuous illustration in public lectures, I considered that an apparatus for exhibiting the expe- riments on a large scale, and with easy management, would not only be well adapted to the lecture room, but absolutely valuable to the advancement of the science. Upon this principle I have constructed a complete set of instruments, which, from their superior magnitude, and peculiar arrangement, are, in my hum- ble opinion, and by the certificates I have been honoured with, are, in the opinion of gentlemen whose judgment I presume will ever be held in the highest estimation, well adapted for the illus- tration of the subject, either in the private study or public lecture room.. ae gt It will be understood from what I have already stated, as well as from an inspection of the instruments, that the mode which I have taken for the production of electro-magnetic phenomena is more simple in its management, less expensive in the process, better calculated for the illustration of the subject, and the reverse of that which has hitherto been used, and which, by its almost entire dependence on the tedious and expensive process of galvanism, has considerably retarded and obscured this new ¥ ’ a ex ad fo att: AR SOK ha a] SH 4 i sit ee et) ae amt ese x 1 TOE gee fige t: vif ‘yee gh earaind Teo ry LS rae nites, im ~~, pie na ia CO Z ( rA “ZL, —e Ny J COL ~ lag ROLL « Ofifte CLES. z Ligd3. HNULAUAUOATATTTI J WAH ps | iii | > {HM Lngraved ter the Lanals of Philosophy.Published ly Baldwin, lradock and Joy. Novemba 1°26. 1826.] an improved Llectro-magnetic Apparatus. 359 and interesting science; for »whenever an experiment was not attended with the anticipated success, the failure was gene- rally attributed to an insufficiency of galvanic power; and in order to increase the effect, it appears that the experimenter had no other means of accomplishing his object, than by aug- menting the power of his battery, or by reducing the size and increasing the delicacy of his other apparatus, the magnetic power being either entirely lost sight of, or regardlessly neg- lected, as if no ways materially concerned in the process. . -I have found, however, by the above-mentioned course of experiments, that the magnetic force is as essential as that of galvanism to the development of electro-magnetic phenomena ; and the apparatus: which I now submit to the attention and impartial consideration of your valuable Society, acting on the principle of powerful magnetism and feeble galvanism, will, I trust, be found more eligible and efficient than any other that has yet been brought belie the public. | —iae— Reference to the Engraving of Mr. W. Sturgeon’s Electro-mag- : netic Apparatus. (Plate XLI.) Plate XLI. fig. 1. A perspective view of an apparatus to show the revolution of a magnet round its own axis. aa the two galvanic apparatuses on their stands b 6, they are acting on the magnet: Ns, by means of the connecting wires dddd; both their copper poles c € are applied to the equator e of the magnet, while the zinc pole z of one is applied to the north pole n, and the zine pole z of the other is applied to the south pole s of the magnet. A wire f is soldered on to the magnet, and bent down at one end to dip into the circular trough e to form the equato- rial connexion; and as all the connexions are made i apd and amalgamated wires, the end of this wire is amalgamated, and mercury put into the trough : ‘all the little cups z and c are also amalgamated at the bottom, and contain mereury; the bottom wires of the zinc and copper poles are likewise amalga- mated to dip in connecting cups when wanted. The magnet has brass wire centers on which it turns, that at the north pole stands ina cup z with mercury ; ‘and the other atthe south pole enters the amalgamated hollow in the screwed end of the upper connecting cup z.' When the connections are made, as above described, on pouring dilute nitric acid into the troughs a a, the magnet will revolve in the way shown by the arrow; but on changing the connexions, by applying the copper wires to the poles, and the zinc ones to the equator, it will revolve the con- trary way; here the magnet only forms the connexion between the electric poles; and revolves around, or with the current which is conducted by it. g g gis the stand which supports the 360. Mr. Sturgeon’s Account of ©. [Nov. magnet ; the equatorial trough e is made moveable on the pil- lars g g, and is fixed by the screws h h. | Fig. 2. A view of a circular metal disk, made to revolve ketween the poles of a horse-shoe magnet; the disc is amalga-- mated round its edge, and dips into a little mercury contained _ ina hollow j of the stand, the centers k k on which it turns, and the hollows that receive them in the forked support /¢ are amalgamated; the screw m allows the disc to be adjusted, and fixed so as only just to touch the surface of the mercury. A horse-shoe magnet N or N s shown by dotted lines, is laid on the stand, then one of the troughs a of fig. 1 is to be adjusted | ~ on its stand 4, till its bottom wire z dips into the connecting cup z, forming the zinc communication, and a connecting wire d with bent ends is to dip into the copper connecting cup c of the trough, and into the cup c of the disc; the communication of the poles being thus made (the current passes from z, through the mercury j, into the edge of the disc, and ee its centers kk into the fork /7, and up to the cup c) the dise will then revolve as shown by the arrow. By reversing either the poles of the magnet, or the electric poles, the revolution of the wheel is reversed ; but if both are reversed, the revolution will continue. in the same way as at first. The six rays are painted on the disc, merely to render the revolution visible at a greater distance. Fig. 3. A stand supporting a needle between two, conducting. wires v0 and pp to show the different effect of electricity on the - needle when passing above or below it; the cup z is common to both, but the other ends have each a separate cup c_c: when the electric current passes along the upper wire, p p the needle | takes the position as shown in fig. 4; but on lifting the connect- ing wire out of the cup p c, and putting it into the cup o c, the current passes through the under wire o 0, and the needle imme- diately goes round to the position indicated in fig. 5; then if you watch the motion of the needle, and keep alternately trans- ferring the wire out of one cup into the other, keeping tiine with the needle, you may bring it into the most rapid revolution that you can eae keep time with. Figs. 6 and 7. A front and side view of a stand with two con- necting cups z and c made of wood, in which the bent iron wire wound round with copper wire is supported by the two copper wire ends. On making the galvanic connexion through the copper wire, the iron wire Peaonies a strong horse-shoe mag- net, and will support a heavy bar of iron as y fig. 7; but on | lifting the connecting wire d, fig. 6, out of the cup z, the weight immediately drops, and on restoring the connexion, the power is restored; then if you change z for c, it will change N fors, . or if you only wrap the copper wire about the iron wire, as a right threaded screw instead of a left one, as in the Plate, it will change n for s.. This is explained by what takes place — in figs 3, 4, and 5. 1826.] an improved . EKlectro-magnetic Apparatus. 361 Fig. 8, a horse-shoe magnet, mounted with two mercurial troughs 77, (fig. 9 shows one separate) ¢ ¢ two cylinders sus- pended on the ends of the magnets, by points within their crowns under the cups vv; their bottom edges are filed away, leaving only four points (as fig. 10) to touch the mercury, by which means. the friction is much lessened. The troughs are adjusted by the screws ww so as to bring the mercury just in contact with the points of the cylinder; the screw points of the upper cups. c c just touch the mercury in the cups v. Upon making the com- munications as before with the cups zz and c c, the cylinders will revolve as shown by the arrows. : Figs 1] and 12 show a front and back view of a dipping needle, mounted between two wires, oand p; they are here placed in the direction of the dip, but the quadrant2 allows them to move’ one quarter round, or to the equator of the magnet, as shown by dotted lines. In their present position the needle will deviate, as figs 4 and 5; and it will be seen the needle cannot: take a position quite at right angles to the wire, owing to the terrestrial magnetism drawing it on one side; but when the wires are carried round to the dotted position fig. 11, the needle remaining as it was, so as to be at right angles to each other, then on passing the current from z through the wire 00, no effect will appear to take place, the needle is only more confirmed to its position, but on passing it through p p, the needle goes round, and dips with its south pole. The wire passes through the wooden cup z, but the two ends of it p and o only just enter their respective wooden cups cc; these wooden cups are placed at an angle of 45° to the horizon, so'that in either position they are similar, and will hold mercury enough to make the contact. : 8 Fig. 13 shows two°of the connecting wires separate, three or ‘four pairs of each of these are required. ! | These figures are nearly one-fifth of the real size, and it will. — be seen that the magnetic power is very great in proportion to the galvanic power. 4 ~ArticLe VIII. Further Observations on the Genus Hinnites, with the addition o another recent Species, indigenous to Great Britain. By J.E. Gray, Esq. FGS. (To the Editors of the Annals of Philosophy.) GENTLEMEN, Paris, Oct. 16, 1826, _ In the number for August last, p..103, I described a recent species of the genus Hinnites of Mr. De France, which I had dis- covered: in the collection of the British Museum. A few days 362 Mr. Gray on the. Genus Hinnites. [Nov. since, on looking over the beautiful and extensive collection of recent and fossil shells belonging to my friend Dr. Deshayes, who is at present engaged in describing and publishing the fossil shells found in the environs of Paris, Ll observed that he had placed the Pecten sinuosus of Lamarck, the Ostrea sinuosa of Gmelin, which is not uncommon on the British coast, as a recent species of the above-named genus, which he has called Hinnites sinuosus, and on examining the shell, I am convinced of the propriety of the situation igen to it by Dr. Deshayes. On account of the worn and shattered state of the other recent species in the Museum not showing very distinctly: the mark of attachment, one or two of my friends have been cndaséd to doubt of its being attached; and, therefore, I am the more glad to add this species to the genus, as it is well known to most British conchologists, that the Pecten sinuosus is always attached to rocks, and is generally found in their holes and crevices ; but the fact does not appear to have been known to Lamarck, who observes, that this species is “‘ very singular — from its deformities,” which are evidently produced by the irre- gular surface of the rock to which they are attached; and two of the specimens in my possession have the upper valve very simi- larly marked to the specimen described in the former paper, and the marks are doubtless occasioned by the same causes. Some- times the shells are scarcely distorted, and they are usually furnished with elongated or long lamellar spines, by which they are attached. 4 | i The fact of the English species having been so long kept in the genus Pecten, shows the great affinity which the genus Hinnites* must have to them; it appears indeed to be an osculant or interme- diate genus between the Pectines and the Spondyli, it being provided with the groove for the pores of the Byssus, like the . | true Pectines, and with the attached shell of the true Spondyli; and at the same time it is separated from the former by the shell being attached by the lamellar processes, and from the latter by the hinge being destitute of any appearance of teeth, although this character loses much of its importance when the hinges of the Pectines are carefully examined ; for many of them are provided with distinct teeth on the hinge-margin, as well as with the curiously-shaped tubercular lateral teeth placed below the ears. * The name of this genus must be changed to Hinnus; for whilst this paper was going through the press, a classical friend has pointed out to me, that the above word is the proper derivitive of Hinnites, and not Hinnita, as I had before inadvertently called it, in my former paper. 1826.] Alcohol derived from the Fermentation of Bread. 363 Articte IX. Alcohol derived from the Fermentation of Bread. By Mr. Thomas Graham. (To the Editors of the Annals of Philosophy.) GENTLEMEN, Edinburgh, Sept. 25, 1826. Two facts of considerable importance in determining the nature of the panary fermentation, have been made known by our ingenious correspondent upon the art of baking bread. He a shown that the fermentation depends upon the saccharine ingredient of the flour, by renewing it when exhausted by the addition of sugar; and provided for the little alteration in the proportion of sugar existing in the flour, before and after fer- mentation, by exhibiting the influence of the baking in convert- ing a portion of the starch into sugar. From the known laws of the decomposition of sugar, it is presumed, with considerable reason, that the fermentation is the vinous. The production of alcohol in the course of the fermentation of bread in baking, which we have found to take place, and rendered appreciable, is, perhaps, a most irrefragable proof of which this theory is susceptible. To avoid the use of yeast, which might introduce alcohol, a small quantity of flour was kneaded, and allowed to ferment in the usual way, to serve as leaven. By means of the leavena considerable quantity of flour was fermented ; and, when the fermentation had arrived at the proper point, formed into a loaf. The loaf was carefully inclosed in a distillatory apparatus, and subjected for a considerable time to the baking temperature. Upon examining the condensed liquid, the taste and smell of alcohol were quite perceptible, and by repeatedly rectifying it a small quantity of alcohol was obtained of strength sufficient to bura, and to ignite gunpowder by its combustion. \The experiment was frequently repeated, and in different bakings the amount of alcohol obtained, of the above strength, found to vary from 0°3 to 1 per cent. by weight of the flour , employed. When the fermented flour was allowed to sour bafire baking, the amount of alcohol rapidly diminished ; and in all cases, the disagreeable empyreuma completely disguised _ the peculiar smell of the alcohol, when in its first diluted state, and invapour. I am, Gentlemen, with great respect, Your most obedient servant, THomAs GRAHAM. 364 Mr, Levy on the Tungstate of Lead. =. [Nov. | Axticue X. On the Tungstate of Lead. By A. Levy, Esq. FGS. &c. (To the Editors of the Annals of Philosophy.) GENTLEMEN, Ir you think the following short notice respecting tungstate of lead worth insertion in the Annals of Philosophy, you will oblige me by sparing a little room for it in the ensuing number. One of the - ita of tungstate of lead in Mr. Turner’s collection offered me very distinct crystals of the form repre- sented by fig. 1. They are much lengthened in the direction of Fig. 1. . : the axis, whitish and translucent; they cleave easily parallel to’ the planes marked 0’, as well as in a direction perpendicular to the axis. The incidences, easily obtained by means of the reflective goniometer, either on natural planes, or planes of cleavage, were as follow : . . b/, 0’ =..99° 43’... B, & = 131° 30’ m, b’ = 155° 45’ a, a? = 106 47 a*,a* = 66 etsy ills MAR eke 1d Bete '92 46 8, b= 15436 Sm, BY = 167 18 1 In some of the crystals, the planes of the modification 6” are wanting ; whilst others are composed of this modification alone, and present the form of very acute octahedrons, most of which are cuneiform. I also found that the very small white crystals, mentioned by Bournon, and which sometimes accompany the 1826.) Mr. Levy on the Tungstate of Lead. - 365 molybdate of lead, present one of the preceding forms ; and as far as I could ascertain, measure very nearly the same angles : they are, therefore, most likely tungstate of lead. - , [ was immediately struck with the almost identity of these measurements with those offered by molybdate of lead, and the only difference I could notice with respect to cleavage was, that in the tungstate of lead, the cleavage perpendicular to the axis appeared to me more easily obtained than in the molybdate. In consequence of this great similarity of crystallographical charac- ters, 1 begged Mr. Children, about two years ago, to examine chemically a small quantity of the substance, to ascertain if it had not been wrongly named, and whether it was not simply molybdate. The quantity he had to operate upon, however, was so small, that no decisive result could be obtained, and in _ consequence of the following considerations, I have placed the specimens in the collection apart from the molybdate, and under the name of tungstate of: lead. I had then noticed that the measurements of molybdate of lead were very nearly the same as those of tungstate of lime ; it appeared besides from the great analogy of forms, macles, and cleavages, as well as the near equality of angles of carbo- nate of lead and arragonite, as well as of phosphate of lead and phosphate of ‘lime, that (to use the language of Prof. Mitscher- lich, which now it is well known how to understand), lead and lime were isomorphous bases. It was, therefore, to be expected | that tungstate of lead would measure nearly the same angles as tungstate of lime; and consequently nearly the same as molyb- date of lead. Another inference to be drawn from what precedes is the isomorphism of molybdic and tungstic acids; that is, the same analogy between them as has been proved to exist between phosphoric and arsenic acids.* With the desire to establish this ~ result upon more facts, | endeavoured last year to procure some artificial molybdates and tungstates ; but Mr. Faraday, to whom I applied, told me they were very difficult to obtain in a crys- tallized state.’ I think, however, that the measurements of tung- state of lead which Mr. Brooke was so good as to show me a few days ago, and which he had taken upon small crystals of that substance (a few specimens of which were lately received by Mr. G. Sowerby), but without noticing their near equality to those of molybdate of lead and tungstate of lime, confirm the results I had previously obtained, and justify the inference I had drawn from it. . Besides this new example of isomorphism, I have been sometime engaged in the examination of a class of substances which present aremarkable analogy of forms, and near equality of measurements, , * These two acids present a case analogous to the one under consideration,; Their ‘combinations with two isomorphous bases producing isomorphous crystals,.those of arse- _ niate of cobalt and of phosphate of iron. — : 366 Mr. Meikle on the Law of Temperature. ENov. among which I shall mention cymophane, peridot, humite, fos- terite, crystallized serpentine, tantalite, &c. the results of which I shall publish when completed ; and I hope that as the number of examples of isomorphisms will increase, the attention of mineralogists and chemists may be directed to this interesting subject, which require the help of both, | ) ¥ 1 shall also avail myself of this opportunity to give the _ description of a beautiful crystal of tungstate of lime, which ~ belongs to the collection of the Right Honourable the Dowager Countess of Aylesford, and which her ladyship has allowed me to examine. y comparing its measurements with those pre- cedingly given for tungstate of lead, the analogy between these two substances will appear. The form is represented by fig. 2, and the crystal is nearly of the size of the figure, and perfect. I have assumed for primitive the square prism represented by fig.3, in which the side 6 of the base 1s to the height as | is to 2-098. Fig. 2. . Fig. 3. BRN Sa » Ae 7b: g::1:2098. ia’ si P,.m = 90°., .m,.m.=, 90°... BY; b=, 100° 40’. .. 6’, b’ = 129°, 27, Bg BS AON? 25; Oy: Pha OOS 00 € Ds Bo meadee ikl - a®, a = 112° 2.. a? :,:a%. = 108° 12’... 0%, at, =,,160°339", ° a, af = 713° 8... at, 3:@4-=,1809 10%; 60900; == 156°, 56 "a, = 151° 33’... .a,.a* = 152° 2]’., .4,.a* = 136° 12’, This magnificent crystal is of a pale yellowish colour, and transparent. Mr. Heuland, on seeing the specimen to which it is attached, had no doubt that its locality was Breitenbrunn, in Saxony. ArticLteE XI. | On the Law of Temperature. By Mr. Meikle. (To the Editors of the Annals of Philosophy.) GENTLEMEN, Edinburgh, Sept. 30, 1826. In the last number of the Edinburgh New Philosophical Journal, I had occasion to point out some very remarkable 1826.] Mr. Meikle on the Law. of Temperature. 367 inconsistencies in the opinions which are entertained by most of the principal authorities of the present day, vegarding the law of temperature. The subject is one of great difficulty, and those who have given it sufficient attention are aware, that there is abundant room for falling into mistakes... In such researches, as is well known, it is no easy task to avoid confounding varia-: tions in the quantity of heat with the variations on our common scales of temperature ; and it is curious that though new terms have been coined for the express purpose of overcoming this source of fallacy, those who.j;were thus. accoutred have not thereby been protected from their former mistakes; from which . it would appear, that the difficulty was owing to something else ‘than a want of words; and that the nature of things was not, in this instance at least, changed by a new name. In the paper referred to, I have attempted both to point out some of the chief misconceptions which exist on this subject, and also to show what law of temperature is alone consistent with admitted principles. No new hypothesis is introduced. But from reconsidering the subject, I find that the law of tem- perature admits of being investigated in a somewhat simpler form, so as entirely to avoid the differential equation, and the determination of the requisite form of its integral, which led those great mathematicians who have preceded me in this | inquiry so far astray. ‘Let ¢ be the temperature, or rather the indication on the common scale of an air thermometer, p the pressure, and @ the density of a mass of air; then.a and 6 being constants, we have from the law of Boyle, p=be(ltadt)........ (A). Now it is obvious, that the specific heat of air under a constant pressure will be to its specific heat under a con- stant volume, in the inverse ratio of the variations of temperature produced in these two different cases by. equal variations in the quantities of heat ; so that the follow- ing expressions respectively contain all the variables which enter - into these specific heats, relatively to the ordinary graduation, viz. A ge Moe sepuy ao 1 1 Salted =——. and — =" , -—-—— dt dg’ l+at di” dp’l+at * The specific heats are = es ana <4 x 1°. But dq the differential of the quantity of heat, being constant, and the same in both terms, is here omitted, as also the constant linear degree of the common scale, 5B 368 Mr. Meikle on the Law of Temperature. | {Nov which are obtained from Equation (A) by making p and ¢ alter-_ nately to vary with ¢, whilst the other is constant. Big a Let the point A represent — 448°. F, or — 266:7° cent. and let the temperature be reckoned on the straight line A B as on the common scale of an air thermometer. Also let CI be a ‘line of such a nature, that any ordinate as BC, EF, HI, &c. may be respectively proportional to the specific heat of a mass of air under a constant volume at the temperatures B, E, H, &c. so that the intercepted areas will denote the corresponding variations in the eeeng of heat, undera constant volume. But MM. Gay-Lussac and Welter! have ascertained by experiment, that the specific heat of air under a constant pressure, exceeds that under a constant volume, in “a constant ratio, which call that of k : 1; wherefore, if these ordinates be every where increased in that ratio, another line G D passing through their extremities must be of the same nature with CI, whatever that may be, and the intercepted areas, of course, to the former as kto 1. j Let BD x 1° be the specific heat of a mass of air under a constant pressure, and let its temperature be raised from B to E, under the same pressure: then area BDGE will denote the increase in the quantity of heat, and EG x 1°, the specific heat under a constant pressure at the temperature E. Now EG : EF :: k : i, wherefore EF x 1° will be the specific heat of the dilated mass at the temperature E, under a constant volume. But E F x 1° wonld still have been the specific heat had the air under its original volume been raised to the temperature E; and because EF : EG :: 1:4, EG x 1° would have been the other as before. Hence the constant ratio of the specific heats renders them independent of the actual density or pres- sure; and, therefore, Ze and Pa are constant quantities. From which it appears, that the algebraic expressions for the specific heats vary inversely as 1 + a¢; or that any ordinate BC, or B D, is inversely as A B, which is the well-known property of a hyperbola ; and, therefore, C I and D G are both hyperbolas having A for their centre, and A H for an asymptote.* Hence, as before, the variations of volume, under a constant pressure, or the variations of temperature on the common scale, * The quantities a and af are only linear expressions, such as B D and B C. Tobe complete, they must be multiplied by the particular linear degree of the. scale to which they belong. . The result which I have obtained is the only one which can make the algebraic and geometrical values of the specific heats agree together, The hypothesis of M. Laplace gives two inconsistent values to both quantities, even algebraically, and a third different from these, but the same with mine geometrically. (See Annales de Chimie et de Phy- sique, xxiii 339, and Mecanique Celeste, livre xii. 98.) " .1826.]° MrvStephers on British Chemical Instruction. 369 form a geometrical progression ; whilst the variations in the quantity of heat are uniform. From this the other conclusions -are easily deduced regarding the relation which subsists between p, eand t, when the quantity of heat is,constant, as may be seen in the paper referred to. _ joa Ud | -. Tam, Gentlemen, your very obedient servant, ! od | Henry MEIKLE. ARTICLE XIL | 7 Suggestions for the Improvement of: the British System of Che- mical Instruction.. By Edward B. Stephens, Chemical As- - sistant to the Royal Dublin Society, : a Dec. 20, 1825. Tue method by which the science of | chemistry has hitherto been taught in public lectures throughout the united: kingdom appears to me susceptible of a variety of improvements. The suggestions which I now offer in the hope of effecting these, are not founded upon my judgment alone. -Though not aware of -any’ similar observations in print, yet 1 am happy to state that many individuals whose scientific acquirements, experience, and rank in society give them an undoubted right to judge, coincide with me in opinion. As their communications on the subject. have continually tended to guide and form my judgment, it is but justice to state my obligations. to them, and forego the credit of originality for the weight of authority.: 5 The regular analytic course is certainly well calculated to improve those who have previously acquired elementary and experimental knowledge of the subject, and who wish to review and systematically arrange in their memory, the facts already stored in it; but it.is morally impossible for those not pre- viously possessed of elementary knowledge to derive similar ‘advantages from attendance on such a course of instruction. The series of lectures at present in fashion in these kingdoms presupposes considerable information already attained. It. is evident from the refined style and learned tenor of the usual course, that a chemical lecturer addresses his auditors both as critics and pupils: he‘assumes that they are imbued with the various literary and scientific knowledge requisite to a clear conception of his plan and language: that he need only allude to the sister sciences of mineralogy, electricity, meteorology, and pneumatics, to be perfectly understood; and that expia- ‘nation and repetition at every step, would be alike tiresome and useless. : | Now we all know from our own experience, that few indeed of those who attend a course of chemical lectures for the first New Series, vou. xl. 2B 370 Mr. Stephens’s Sugyestions for the Improvement [Nov. time, are possessed of general knowledge sufficient for a cot- rect comprehension of the subject; and that with respect to the majority, the lecturer is proceeding to build before the founda~- tion is really laid. The consequence is, that, even the most attentive and well inclined amongst his youthful: auditory are unable to follow him in his AOE and are often thrown into partial despair ‘by the apparent difficulties of the study. An instance or two will explain their peculiar embarrassments. The first time they hear of specifie gravity at-a lecture, its uni- versal relation to solids, fluids, ney ases, will perhaps appear incomprehensible to them; and all the necessary calculate and corrections respecting temperature, atmospheric pressure, ‘and hygrometric moisture, tend to place the matter in greater obscurity. But is the subject naturally obscure? Certainly not: the error lies in the mode of instruction adopted by the lecturer, who brings forward barometers, thermometers, and hygrometers, and applies them at) once to his subject, taking for granted that his auditors are all sufficiently informed. of their construction and use by a previous study of natural phi- losophy ; which certainly ought to be the case, and certainly is not, as education is generally managed... | Again, when a lecturer treats of precipitation at the com- mencement of his course as usual, he proceeds to exemplify it in a way that must inevitably create. a confusion of ideas im an uninformed mind. For instance, he pours a solution of muriate of barytes into another of sulphate of soda, points toa white cloud appearing in the mixture as an evident precipitate, and informs his class that it is produced by the double decom- position which has taken place between the two salts, as the result of their compound elective attraction, and that two new substances are thereby formed—sulphate of barytes and muriate of soda. In this short explanation a pupil is introduced to a variety of new matters, ideas, and terms. He hears the word’ “ precipitate ” used for the first time as a noun, whereas he had usually understood it as a verb active “ to throw downwards,” _ and is not a little confused to hear of precipitates forming clouds, or rising to the surfaces of liquids. He may never before have heard of the four salts concerned in the experiment, and the only comment on the matter afforded him at the time generally is—that what is commonly termed muriate of soda, is properly a chloride’ of sodium !—all of which remain to be explained to him in future lectures. A hundred similar instances might be adduced. 3 ‘hus every explanation of the laws which influence matter, contains (according to the present system of chemical instruc- tion) something that a pupil who attends for the first time is not prepared to understand, and frequent allusions to substances he has not before heard of, but which he is told he will hear of 1826.] of the British System of Chemical Instruction, 871 - again.’ In consequence he is'induced to postpone thought and reflection to a more convenient opportunity, and thus acquires the bad. habit of listening passively to what conveys no definite notions to his mind... rs : If, on the contrary, a lecturer with partial consistency exhibit the phenomenon of precipitation, without informing his class what the agents are which he employs, a young pupil, who is exerting this faculties to learn the name and character of every substance brought forward, feels particularly disappoimted and confused if he be stinted in this manner in the information proper to an analytic course. _ Instead then of seeking to effect the double object of instruct- ing the learned and unlearned at the: same time, (which neces- sarily produces one or both of the evils above mentioned) a lec- turer who has studied ‘ the conduct of the human understand- ing ” will endeavour to accomplish a separation of these two -classes, that he may prepare for each suitable information. The instruction of the advanced student is sufficiently provided: for _ -by the usual routine; but to really benefit those commencing the study, he will perceive the necessity of constructing a series -of lectures on a very different plan. ‘His grand object in these should be,—to convey elementary instruction in a style and manner comprehensible to the plainest capacity,—excluding -every idea of display and. artificial system which might inter- fere with so desirable an end :—his surest way to attain a cor- rect view of what such a course of instruction ought to be, is, -to suppose himself a pupil, and consider what kind of lectures he would require in similar circumstances. | Keeping this in view, he may readily frame a course of pre- paratory lectures that shall proceed with ease and satisfaction to all. concerned, On the first day, each element may be dis- played in succession, and its distinguishing properties familiarly stated; (avoiding its combinations, for it is impossible a lec- turer can be understood, if he speak of them at first ;)}—and by the time all the simple substances in nature that we are ac- quainted with are thus reviewed and classified, a pupil will be astonished to find how few they are, and what an easy science wie Hert appears when clearly entered on. The elements (as exhibited) may remain in their order on the table during suc- ceeding lectures, in: which their primary combinations should be experimentally explained, and completely gone through be- fore the secondary combinations, or salts, are brought forward. The latter: must be described in their turn before the complex animal and vegetable products can be consistently treated of. , Whenever a compound is introduced, its elements may be again referred to with effect, for here repetition is truly judi- cious, If pupils have constant opportunities of turning their .attention to explanatory —— and groupes of the simpler B2 372 Mr. Stephens’s Suggestions for the Improvement [Nov. substances which together form the compound that the lecturer is speaking of, they will have comparatively little difficulty in recollecting the composition of bodies, No actual preparation of the elementary substances should be attempted before a class of beginners, for they are not prepared to understand the rationale of their production. This ‘exhibition should be re- served for another course, and for another class who are sufli- ciently advanced to comprehend the means by which the lec- turer obtains them, and are in no danger of supposing that he is making hydrogen or oxygen gas, when he is only liberating it. In fact, this science is so extensive, and so peculiarly liable to misconception in its language and objects, that two distinct courses are indispensibly requisite to avoid inconsistency and confusion, and enable a teacher to do justice to his class, The first,—simple, explanatory, synthetic,—ascending from elements | to compounds, and so arranged that the class may arrive at a knowledge of the laws of nature as the result of direct experi- ments. Here the lecturer should address his auditors as persons totally ignorant of chemistry. This course ought to be prepa- ratory to the second, wherein he might oui on the present system; that is,—first promulgating general laws, and then illustrating them by exhibitions and experiments ; and so*far as the previous lectures had made his class acquainted with the substances experimented upon, so far will they really understand and profit by these. ? . The latter may be termed the descending, the analytic'lec- _ tures, in which the decomposition of substances might be expe- rimentally pushed to the utmost limits of our skill, the methods of detection and separation thoroughly explained, and the.ap- plication of chemistry to the arts and manufactures; to phar- macy, metallurgy, agriculture, &c. demonstrated with all the eloquence and collateral information which ean be brought to bear upon the subject. The refinements of electricity, magne- tism, may now be displayed with consistency and effect ; and a discussion of the principal conflicting speculations which divide the chemical world may also be intelligibly entered on. By these arrangements, all who are prepared to enjoy the heights of science may be gratified without the loss of time they have, hitherto sustained in listening to a repetition of well known facts, (which the present mixed system renders unavoidable) ; and those who now sit year after year endeavouring to under- stand the subject, will also be enabled (by the preparatory course) to derive enjoyment and instruction from elevated themes, which would otherwise be to them the essence of per- _ plexity. ) | In the elementary lectures, the various substances should be arranged as much as possible into the distinct and familiar groups which the pupil’s mind would naturally place them in, 1826.] .of the British Sysiem of Chemical Instruction. 373 His memory is aided as much by their classification into metals, earths, gases, combustibles, acids, alkalies, &c. as that of the botanist is by the Linnean arrangement of plants ; and though both are in some respects nratieal, yet both are decidedly useful. In fact, the comparative ease with which the sciences are studied in latter years arises from this facility of arrange- ment, which enables the student to refer many hundred (in some cases many thousand) individuals to a very few classes ; each possessed of a common character or family likeness, In che- mistry, unfortunately, the electro-positive and negative clas- sification (though scientifically correct,) requires so much pre- vious knowledge for its proper comprehension, that a pupil is altogether debarred from its aid in making his first experimental acquaintance with the science. It would, therefore, perhaps be - as well not to press it on his attention, till he had learned sufhi- cient to fully understand and appreciate it. _ A junior class cannot see too much of the practical opera- tions of the laboratory as soon as it can comprehend them. Whenever the preparation of a substance will not distract atten- tion from the lecturer, as he proceeds to new matter, and whenever his time permits, it will be wise to bring his furnaces before his pupils, and convert the mysteries of the laboratory into engaging illustrations, and welcome aids to memory. . In the instruction of this junior class, a lecturer’s, object should not be to teach all that is known of the science, but to lay a solid foundation of general facts in the youthful mind, and create in it an ability and a desire to work out its own instruc- tion, while he unfolds the means, and gradually implants in it the habit of industrious investigation. | _ Proceeding in this spirit, he will not dwell on the minor salts of the vegetable, animal, and mineral world, unless he can asso- ciate them with some agricultural, mining, physiological, or medical comments, which are always valuable as practical illus- trations of the use of chemistry. The merits of rival hypo- theses (or unproved theories) are matters interesting only to more advanced students, and may safely be omitted for the pre- sent, Iam also of opinion, that, however consistent it may be to commence an advanced course with separate lectures devoted to the explanation of the laws of chemical action, and what are termed the canons of chemistry,—yet they may with great pro- priety be omitted in an elementary one, inasmuch as a pupil cannot then apply them: hé may remember them by great ex- ertion, but such knowledge hangs a dead weight on his memory till he is afforded an opportunity of deducing them from his own sractice, or from observations on the experiments exhibited at ectures. A great evil is done when the mind of a youth is bewildered by having more information pressed upon him than he can receive at once. Confusion induces despondency, and 374° Mr. Stephens’s Suggestions for the Improvement (Nov. the mischief is increased by his loss of that part of the lecture which often passes unheeded duting the’ continuance of his. perplexity, leaving an opening for fresh misunderstandings that, e may never afterwards have opportunity or leisure to remove. Carelessness and dislike frequently follow in the train of con- sequences, for no one can really love a science that is apparently © above his comprehension. ei cheng Now, the doctrines of aggregation, affinity, decomposition, combustion, absolute, specific, and latent caloric, &c. &c. which, with their definitions and illustrations, form he substance of several lectures at the outset of a scientific course of chemistry, under the present arrangement, are poured into a young pupil’s ear long before he can possibly understand to what they relate ; ignorant as he must be at first of the substances which he sees employed in illustration. \ In the select elementary course, this inconsistency should be carefully avoided, and these doctrines introduced only when experiments directly illustrative of the properties of each substance afford opportunities of explaining the accompanying appearances, and consistently entering on the rationale of the matter. If no more be said at one time than refers to experiments and exhibitions already made, the progress of pupils will be real, rapid, and satisfactory. They are always inclined to generalize and draw conclusions from analogy (when they understand a subject,) as quickly as a pru- dent teacher should wish: his chief care on this point will therefore be to correct the notions they instinctively form, (or most likely sanction them) ‘by declaring the true state of the. ease at the end of each series of experiments. It is judicious. at all times to give them opportunities and habits of exerting their reasoning powers. The mind is pleased with its own labours and discoveries, and memory fondly retains such little triumphs long ’after the dogmas impressed by the voice of au- . thority have faded from recollection. ‘ Definitions without examples are, to the generality of young persons, very perplexing and unprofitable. To say the truth, they are matters rather of curiosity than utility in the present improving and changeable state of our science ; and on weak minds are often found to act like fetters which cannot easily be shaken off when new lights are shining to stimulate them to ' mental exertion. Since the discovery of the intimate connec- tion of voltaic electricity and magnetism with chemistry, for instance, all our old definitions of the science must in a great measure go for nothing. ) In adherence to the principles advocated throughout, the history of the science should be deferred till the end of the first course, or better still, till the beginning of the second. By this time the leéturer will be intelligible when he adverts to the energetic labours and-brilliant inventions of his predecessors, '1826.] of the British System of Chemical Instruction. 375 and may fearlessly assume a loftier style, suitable to the dignity of his subject. But if he enter on a critical enumeration of the discoveries of Scheele, Higgins, Richter, Lavoisier, Berthollet, and Davy, before his class is well grounded, nay, far advanced in knowledge of the facts of Chemistry,—the labour will be as much misplaced, and of as ‘little service, as a display of the refined methods of La Place’s Mecanique Celeste would be to one who is labouring through the Elements of Euclid. | A judicious recapitulation of the most important facts. at the ee ra of each lecture, and a brief summary of them at the commencement of the succeeding one, will be found eminently useful throughout the preparatory course. Almost every young person understands a subject better by having it twice ex- plained, and some are in absolute need of repetition, where the doctrine is entirely new to them. Those necessarily: absent from a particular lecture, are at the next in evident want of a summary of what they have lost, to enable them if possible to . recover it by reading, and profit by the remainder of the course, which is, (or ought to be) an exhibition of particular facts, and general berries on them, so arranged that the first parts of the series shall form natural and easy stepping-stones to enable a constant audience to arrive at the last. : , - An hour’s lecture is perhaps too much for a very youn audience. Few youths of either sex have learned to command their serious attention so long, and it is of particular conse- . quence to avoid fatiguing it. It is perhaps of equal importance to avoid distracting it by entering upon unconnected topics in» the same day. The convenience of both parties must of course determine the times and duration of the sittings, but it will be invariably found that the oftener they can meet, and the less in proportion the lecturer attempts to impress on his pupils’ re gat at each meeting, the greater effect will his instructions ave. sai lei A lecturer to a junior class should not only speak slowly and distinctly, but if possible avoid reading'to them, The prepara- tion of manuscript lectures necessarily consumes a large portion of time; and, after all, his pupils will yield far more deference to _ passable extemporaneous, than to the best written communica- tions. This is quite natural, and a teacher who speaks from the fullness of his subject (using his bottles and. glasses and Specimens for memoranda as he proceeds), not only commands greater attention, but really acquires a more intelligent and con’. - vincing style than the best reader can hope to attain. Eloquence is not indispensibly necessary to an instructor in this science : ~ high-wrought mystical language, and all attempts at display, are foreign and injurious to the end proposed, particularly be- fore an elementary class. Ifthe lecturer be really possessed ot the desire to teach, and set about it earnestly and unaffectedly 376 Mr. Stephens’s ‘Suggestions of the Improvement [Nov,. —like'a-gentleman called on.to explain what he knows on;an° interesting subject to a company of his friends, he may be almost certain of success. ; | | In imparting a knowledge of this science, a speaker has vast- advantages over an author, The. illustrations of books are limited to drawings; whilst in conversation a teacher can add to these experimental exhibitions and specimens which. enable all the senses to aid in fixing an association of ideas in the memory. He can employ emphasis or gesture, repeat or omit’ Parag cine facts, refine or lower his style as may appear proper. His mere glance awakens attention. He. can explain, if it appear he has been previously misunderstood, bring forward the latest and most interesting facts applicable to his subject, aud make even accident the ground of pleasing and instructive remark, It therefore requires no. great depth of observation to enable a lecturer to determine which of the two systems, writing or speaking, he should incline to, and cultivate. bd _. One of the greatest advantages which a chemical lecturer may avail himself of, is that of conversing with his class after lecture; and fortunately the benefits are reciprocal. He is allowed an opportunity of coming at. their difficulties, answer- ng objections, and removing misunderstandings by simplifying he subject. ..A single misconception at the beginning of a ecture is often sufficient to prevent a pupil comprehending _vhat follows, yet-it is impossible at the time for a lecturer to renétrate and remove the cause of his embarrassment. He ght therefore to invite regular explanatory conversations with he class for his own sake as well as theirs, for it cannot be reditable to a teacher to be incomprehensible. to any of his upils, When the children of operatives form a portion of his. class, communication on both sides is still more necessary. As it aveals to him their peculiar deficiencies, he will perceive the ropriety (indeed the necessity) of explaining more than trictly belongs to his own science to render it fully understood. ‘hey generally hear local names and terms of art widely diffe- ant from the scientific phraseology, but which nevertheless a _2eturer must make himself master of, to become intelligible : i fact, he must translate his words into theirs as he goes on, Vhen he speaks of elements, their thoughts are perhaps fixed n fire, air, earth, and water, which still maintain that rank in me of their school-books:; salt conveys only the idea of the alinary variety, and salts (in their conception of the term) is -2stricted to the pharmaceutical preparations of Cheltenham, ~ochelle, Epsom, &c. Gas will most likely be limited to our com- ,on source of illumination ; spirit is generally used to pi ea ay acid employed in the arts; metal is understood in different unses by the iron-founder, the brazier, the glass-blower, and the 1826:] of the British System of Chemical Instruction. 37% road-makers and tin-is particularly, applied. by. mechanics: to. designate that useful household ware the principal ingredient of which is iron. Our scientific verbs, in many instances, convey no distinct notions to their understanding; and a. lecturer who uses them without explanation, might as well speak in a foreign, language. He says “ the metal is oxidized,” where they would only understand the term rusted. He describes an acid as saturated by an alkali, iron as oxidized in the smith’s fire, and lime as neutralized by carbonicacid.gas ; whereas many of his class are perhaps only accustomed to hear, “ the acid is killed,” “ the Iron is poisoned,” “ the lime is dead.” If the conversational system be adopted, all such misunder- standings will quickly be removed, and a sensible lecturer will gladly avail himself of it, as the best means to discover his own defects in teaching. If the impartial questions and lively sug- gestions of pupils were freely permitted and generally encou- raged, various important discoveries would naturally ensue, and many of the systematic errors and absurdities which have hither- to disgraced all sciences, would have been quickly discovered, and banished; or perhaps never adoped. In laying a sound foundation for scientific acquirement in the youthful mind, it is very unwise to encourage (by example or commendation) a taste for hypotheses and speculations. With such an imaginative habit in early life, nothing is easier than to be mistaken. The rage for systematizing is perhaps the greatest bar to the attainment of truth in every branch of knowledge : in the science of chemistry it has been actively mischievous. In the last century, Phlogiston, like a pagan deity, occupied all minds to the exclusion of every important truth which interfered with its ideal existence. Since its downfall, oxygen was main- tained to be the sole acidifying principle, and the attraction of the mass upheld es destructive of definite proportions, as strenu- ously as if their champions could not err. A brief essay of this nature would not have space to enumerate all the chemical hypotheses that were downright errors: the words are now looked on as nearly synonymous. In the interesting sciences of geology, electricity, and meteorology also, this unfortunate taste for generalizing favourite facts has hitherto been very pre- valent, and in consequence, the authors have been universally sus- Pent insomuch that an experienced reader learns to distrust. heir opinions and inferences as completely as if they proceeded from professional advocates on a point of law. novice in - science, however, too often acquires corresponding bad habits of speculating and taking things for granted, and frequently loses valuable time in the study of authors who dogmatize on the laws and operations of nature, as confidently as ifthey were in her secrets. _ Young students are frequently deceived by this plausible 378 = Mr. Stephens’s Suggestions for the Iniprovement [Nov. and dictatorial style, and forego the right of thinking for themselves, till they are rékiied” from their false security by reading contradictory accounts, assigning different causes for the same effect, and thus fortunately discover that both parties have been unblushingly stating their guesses as matters of fact. Perhaps the greatest improvement in education, effected in modern times, is the system of mutual instruction which has been so happily applied to the diffusion of chemical knowledge in the national institutions of France. On this plan, each of a numerous class of pupils undertakes in turn to deliver, or assist at a lecture on a given portion of the science, (on carbon, for in- Stance,) under the direction of the professors. This creates a necessity that each shall thoroughly uuderstand the part to which he applies himself, to enable him to instruct others with credit and effect. He must be prepared to make experiments, to answer questions, and explain the difficulties of the subject to his companions ; and it is invariably found that in these cir- cumstances they learn with quickness and satisfaction. Whether this proceeds from sympathy and purity of reasoning on their part, or from the absence of all display and repulsive pretension on his, whether their attention is rivetted by the novel sight of their companions successively appearing as lecturers, or that the science is simplified by the familiar and modest language which is naturally employed on these occasions, it is certain the effect is most beneficial, and the plan consequently worthy of earnest attention. 3 7 In a public laboratory where the system of mutual instruction and investigation is adopted, students soon perceive the value of each other’s company. Almost every one is possessed of some peculiar character or turn of mind, from which his companions may derive a benefit they could not separately have attained, For instance, the talent of one is to originate idéas: to invent ; of another, to seize on and apply the invention to purposes of utility ; of a third, to follow up these notions by a patient expe- . rimental reseach conferring satisfaction and certainty by every er in his progress; the taste of a fourth lies in reading, and he brings valuable collateral information to bear on the subject’ under examination; while a fifth amuses himself in talking about the matter to every one, and collecting various opinions and advice for the benefit of his more studious companions, The attribute of a sixth is foresight, of that peculiar species, which conjures up objections of every probable and possible shape, and thereby ensures to his more sanguine friends the advantages of experience, without the loss of time and labour usually paid for it. In addition to these may be observed an embryo critic, possessed of that happy talent which guides some minds almost instinctively to the clear, perception of a lurking error, as something vitally noxious, employed in separating 1826.] of the British System of Chemical Instruction: 379 facts from mistakes, detecting the “ beggings of the question” which his eager companions are unconsciously indulging in, and good humouredly proving their profound ignorance of all that is not established on the certain basis of experiment. Wherever this system is applicable, similar happy results await its introduction. An experienced pupil and a novice, placed together at a table or a furnace, will proceed to acquire knowledge with double efficacy. Two pairs of hands are neces- sary in many operations, and two heads are always better than one. The younger is continually asking questions which induce the elder to search into the stock of knowledge actually in his ossession, to arrange, and to state it intelligibly in answer. he younger acquires by example a facility of operating, and as’ a matter of course, day after day, receives a detail of the expe- rience of the elder‘in familiar language at the instant he has need of it, and an opportunity of applying it to use. This prac- tical instruction, when associated with his own experimental proof of its correctness and value, becomes indelible. Again, one can refer to books, while the other attends to the work ; one may consult the professors on difficult points, while the other watches the progress of an experiment, and records the necessary observations: Both co-operate in emergencies, and sympathize in success and disappointments, Ga, Wek ~ Where such an arrangement for the diffusion of chemical. - geience is adopted by a public ‘institution in these kingdoms, its resident lecturer may be relieved from much of the toil of ' private instruction generally allotted to him under the present system. His cares for his working pupils may then be limited (as in France) to directing their studies, allotting proper por- tions of the science for their own lectures, suggesting appro- priate subjects for their investigation, explaining the rationale of new phenomena, and giving a word of assistance to all as they require it while engaged in working out their own infor- mation. wae at - He may commit to their zeal and activity the determination of all matters of minor interest, or of mere curiosity, which would otherwise seriously. encroach on his valuable time, but which may be made excellent assays for their practice. Work- ing pupils may soon be made tolerable assistants; and by a little arrangement to apportion experimental labours to their several degrees of skill and knowledge, the lecturer may super- intend a dozen investigations and analyses in operation at once around him, and effect more in one season by their judiciously combined efforts, than he could unaided, in ten. ; ’ His proper sphere would then be superintendance, Like the Captain of a ship, he would generally be able to effect more by directing others in their operations, than by working himself; 380, Mr. Stephens on British Chemical Instruction. [Nov. inasmuch as the labour of the head is more-valuable than that of the hands. | Botw The only inconvenience which in France has been found to result from a pursuance of this system of “ mutual instruction ” is, that the pupils by their combined. efforts sometimes outstrip their teachers, if the latter neglect to go hand in hand with them. in the race of knowledge: however the success of Pestallozzi’s mode of education (whose tutors in many sciences learn. with, or only one lesson before, their scholars) has almost overthrown the necessity of instructors assuming scientific omniscience and infallibility as indispensible attributes. | 3 It is delightful to observe what progress is made in any science by social ‘communication. In chemistry it is particu- larly conspicuous. For example, Robert mentions a fact of which Richard was ignorant, and which completely enables the latter to understand another analogous case that was previously incomprehensible to him for want of it. He joyfully announces the new light which has burst upon him, and the een views it opens. Robert’s fact is now illuminated by Richard’s com- mentary, and thus, returning with interest to the former, recipro- cally extends his sphere of mental vision. In this way both cheerfully climb the heights of discovery, alternately pulling or pushing each other upwards, till they gain an elevation far be- yond the power of either separately to attain: now confirming each other’s views by. agreement; then rendering assurance doubly sure by a difference of opinion which leads toa closer investigation: frequently discovering and freeing each. other from long-cherished errors, which had~ hitherto like fetters im- peded their ascent ; and which they would have borne, perhaps through life, had they travelled singly and selfishly... Thus both reciprocally enjoy the double advantages attaching to the characters of tutors and pupils. As comrades they assist, -and as councillors they advise. Their pursuits and intimacy constitute them excellent judges of each other's notions, proceedings, and general character, and insure to each'in turn the benefit of the sagacity of both. These advantages seldom terminate with theircommon labours. The associates have become warmly interested in each other’s cares and amuse- ments, sorrows and joys. Continually engaged in acquiring a similarity of knowledge and identity of opinions, enjoying the pleasure of assisting, as well as the benefit of assistance, and observing in each other the various estimable qualities in- duced by their peculiar course of study, their intimacy naturally improves ito a friendship built on the best foundations; partici- pation of elevating knowledge which never satiates, interchange of good offices, and respect for the talents or industry they severally evince, and have constant occasion to appreciate, 3826.) Ona peculiar Substance contained in Sea-Water. 381 ARTICLE XIII... Memoir on a peculiar Substance contained in Sea Water. Bs M. Balard, Apothecary and Chemist to the Faculty of Sci- ences, at Montpelier.* sia { Hap repeatedly observed, upon treating. the washings. of the ashes-of the fucus which contain iodine, with an aqueous solution, of chlorine, that after having added, a solution of starch, there was not only a blue colour, occasioned by the iodine, but also a little above it, a yellowish colour of consider- able intensity, i : This orange yellow colour was also apparent when the mother water of our salt-works was treated.in the same manner; and the tint was strong in proportion to the concentration of the liquid. The production of this colour is accompanied with a peculiar penetrating smell. | b-shyi I examined the nature of. this colouring principle, and my first attempts led me to the following observations : eR _... 1. The mother water of the salt works, treated with chlorine, loses its colour and characteristic odour when it is exposed for a day or two to the air, and chlorine does not afterwards repro- duce the same phenomenon. il 4 . 2. If it be treated with the alkalies or their sub-carbonates, the smell and colour are also lost. bh Bancstiyon le - cavi: _ 8. The same effects are produced when any reagent.is added to the coloured fluid, which yields it hydrogen, either directly or. by the intervention of water. Lovet _ These effects are produced by sulphurous. acid, ammonia, sulphuretted hydrogen, the hydrosulphurets, but especially by a “mixture of zinc and sulphuric acid, which presents nascent hy- drogen to the fluid. +N 4. When the fluid has been decolorized by the alkalies or bodies containing hydrogen, the addition of chlorine restores the original colour. P tpdy lore Two explanations naturally present themselves to account for these various phenomena ; in the first place, it may be supposed that the yellow matter is a compound of chlorine with some substance contained in the mother water of the salt-works ; in the second place, it may be imagined that the colouring matter ~ had. been evolved from some of its combinations, by the chlo- rine, and that this had taken its place. . '. To determine which opinion to adopt, it was requisite to obtain the colouring matter in a separate state ; its volatility. afforded some hope that distillation would be sufficient to separate it from the liquid, and I had recourse to. this process. -- * From the Annales de-Chemie and de Physique, xxxii. p. 337.0 - 682 M, Balard, on a peculiar Substance...) (Nov. The salt water possessing its yellow tint, when subjected to distillation, does in fact evolve, almost as soon as it boils, ver thick vapours that are condensed by. cooling into a Houid, which I found to possess the greater number of the properties of the coloured liquor; but they were not so distinctly marked. This liquid was off a reddish yellow colour, its smell somewhat resembled oxide of chlorine, it was not acid, lost its colour by the action of the alkalies of sulphurous acid‘and sulphuretted hydrogen, &c. and, in fact, by all the re-agents which de- colorized the water of the salt-works itself after the action of chlorine. It cannot hence be doubted that this first product of ‘the distillation contained the substance in question, especially as the remainder of the liquid had lost in this respect all its ‘original properties, Its colour’ had disappeared ; instead of its enetrating smell, there remained only an ethereal smell, which I shall again mention, Chlorine had not the power of restoring the yellow colour, © ie Penk. In order to obtain this substance in a pure state, it remained ‘only to separate it from the water which was volatilized with it. With this intention I passed the orange vapours over chloride ‘of calcium. They were condensed of a deep: red colour in small drops, which were very volatile, filling the small vessel in ‘which they were contained with vapours in colour resembling nitrous vapour. I believed that I had thus obtained’the colour- ding matter in a state of purity, but the process was unproduc- tive. I reckoned that an operation had succeeded when it gave me one drop of the liquid.. Such minute quantities of matter allowed only experiments almost microscopic. I owe to them, nevertheless, the first essays which I made upon the nature of this substance, and the researches which I afterwards made on a larger scale confirmed them. was at first induced to take this substance as a chloride of iodine, different indeed from those compounds which are already. ‘known to chemists ; it was in vain that all my trials were di- rected to this end. It gave no blue colour with solution: of starch, nor with solution of sublimate ; and as it gave a white precipitate with protonitrate of mercury, and also with nitrate of lead, Xc. it was evident that it contained no iodine. On the other hand, I had repeatedly subjected this substance to the influence of the voltaic pile, and also to a high temperature, but it did not in either case exhibit the slightest appearance of ‘decomposition. Such resistance could not fail to suggest the idea, that I had to do with a simple body, or one which acted in the same manner as simple bodies; and this opinion has been strengthened by every trial to which I have subjected it. I imagined it to be a simple substance, possessing in its chemical relations, the greatest resemblance to- chlorine and iodine, and forming analogous combinations; but always presenting physical and 1826.) oo) contained in Sea Water, © 383 distinguishing it from them, | M. Anglada advised me to call this substance Bréme,* deriving this name from the Greek Bpwnos ( fetor.) : Two processes may be freed for the extraction of brome : the first has already been mentioned ; it consists in’ distilling the mother water after the action of chlorine, and condensing the orange vapours which come over at the moment. of ebulli- tion. | By this process, which is a slow one, only a small quantity of impure brome is obtained. I satisfied myself that it occurs always mixed with a ternary combination of hydrogen, carbon, and brome, analogous in the nature of its properties, to hydro- carburet of chlorine. On these accounts I abandoned this pro- cess when I had discovered, another, more easy of execution, and giving purer brome and in larger proportion. This process consists in treating the mother water with chlorine, and I then pour some ether upon the surface of the liquid, and I fill. the vessel entirely ; by strongly agitating these two. liquids after- wards so. as to mix them, and then leaving them some moments to allow of their separation, the ether floats, having assumed a fine hyacinthine red colour, whilst the mother water becomes colourless, ahd instead of the penetrating and irritating smell of brome, it has metely that of the ether which it holds in solution. . : ert - The coloured ether, which is a true ethereal solution of bréme, when agitated with an alkaline substance, and especially with caustic potash, loses its colour and disagreeable smell. The potash absorbs the brome, and by successively agitating the yellow mother water with ether, and the coloured ether with potash, [ succeed in combining all the brome of a great quantity of the mother water with a small proportion of alkali. The potash gradually loses all its alkaline properties, and is converted into a saline matter which is soluble in water, and crystallizes in cubes by the evaporation of the liquid: it is these cubic crystals that I successfully employ for the preparation of brome; I mix these crystals, after pulverizing them, with purified peroxide of manganese, and upon this mixture, put into a small distilling apparatus, I pour sulphuric acid diluted with half its weight of water. This acid, if it were mixed with the crystals alone, would extricate white vapours and very little brome, and the same effect is produced if it be used with the mixture of salt and manganese, in a more concentrated state, but employed as directed it produces orange vapours that condense into small drops of brome, and which may be collected by immersing the end of the retort into the bottom of a small receiver filled with cold water; the vapours of brome dissolve in the water; that which _. * A notice of the discovery of this substance, under the name of Muride, was given ‘in last month’s AnnalsveaEdite . chemical properties which furnished the strongest reasons for 384 M. Balard, on a peculiar Substance [Noy. condenses*in the neck of the retort precipitates to the bottom of the vessel on account of its great specific gravity. Whatever may be.the aflinity which water possesses for this body, the stratum of liquid which surrounds it is very soon saturated, and this surrounding the brome, it secures it from the solvent power of the superior strata ; to obtain it in a state of great purity it is afterwards necessary only to separate it and to deprive it of the water which it may retain, by distilling it from chloride of calcium, OT) The properties of brome are, that, when examined in mass by reflected light, it isa blackish-red fluid, but when a thin stratum is Lyre between the light and the eye, it is of a hyacinthine red colour. Oot Wr Its disagreeable smell reminds one of. that of the oxides of chlorine, but it is much less intense; its taste is ex- tremely strong; it acts upon organic substances, upon wood, cork, &c.; it corrodes the skin especially, giving it a deep yellow colour ; this colour, which is less intense than that produced by iodine, like it, disappears after some time ; and if it have re- mained in contact with the skin forsome time, the colour dis- appears only when the epidermis is destroyed. tacts strongly upon animals, a single drop put into the bill of a bird killed it; its specific gravity, as nearly as I could ascertain it with the small quantities of the substance, was 2266, and when exposed to a temperature of 18° centig. it is not rendered solid; it is readily volatilized, which is a great: contrast-to its specific gravity ; when a drop of brome is put into any vessel, it is immediately filled with a deep orange red ‘vapour, which by its colour might be mistaken for nitrous acid, if it were not distinguishable from it by numerous properties. It boils at 47° centig. heat, which thus varies the physical state of bréme, has no action at all upon its chemical nature. I did not find any decomposition, by passing its vapour through a luted glass tube heated strongly red: it is not.a conductor of voltaic electricity ; I ascertained this by preventing the decom- position of water, by interposing a portion of brome three or four lines in length in one of the conductors: neither does elec- tricity appear capable of decomposing bréme; this substance, when submitted to the action of a pile, strong enough. to decom- pose water and saline solutions, suffered no apparent diminution | of volume, no evolution of gas, nor any deposit of matter upon the ends of the platina conducting wires. In a word, it gives no indication of decomposition. Gar is The vapour of bréme does not support combustion; 2 i. taper when immersed in it is soon extinguished, but before it goes out, it burns for an instant with a flame which is green at the base, and red. in the upper part, just as it does in chlorine as. a, a Oo. & Brome is soluble in water and alcohol, and especially in 1826:] |... °° .- contained in'Sea: Water. .- © 385 ether, it.is but very slightly soluble in sulphuric acid; olive oil acts slowly upon it; it does not redden. tincture of tournsol, but decolorizes. it rapidly, very much like chlorine... Solution of indigo in sulphuric acid is also decolorized by it. : The great analogy which I had remarked between the action of bréme and that of chlorine upon vegetable colours, made me think that it existed also between the causes of these pheno- mena; and that brome, having affinity for hydrogen, probably took it as chlorine does from organic bodies which are put in contact with it, This was the motive which directed my expe= pupae in my researches after a combination of hydrogen with rome. I first tried to make them act directly upon each other, but without success. My trials were more fortunate when I put . br6éme in action with several gaseous compounds of hydrogen. I obtained by this method,a colourless gas, strongly acid, which when absorbed by potash reproduced the cubic crystals which { had already obtained, by agitating the alkali with ether con- taining brome. he: | _ L afterwards tried to procure from these crystals the gaseous matter which they seemed to contain. When treated with con- centrated sulphuric. acid, they evolved an acid gas which I re- cognised as hydrobromic acid, when I had found that chlo- Tine decomposed it, disengaging vapours of bréme, and that. certain metals, by taking this substance from. it left only pure hydrogen. This acid may be prepared by several processes: ° 1, I exposed during some time hydrogen mixed with the va- pour of brome to the solar rays, without observing any sen- sible combination ; but I found that hydrobromic acid gas was produced, by exposing the mixture to the flame of a taper, or. still better, ie introducing an ignited iron wire into the receiver which contained it. 1 , a7 In all these cases, the, action is not propagated throughout the whole mass, as occurs with chlorine and hydrogen; the combination is produced only around the hot body which occa- sions it.. It probably would not have so happened, if I had been able to collect and measure the vapours of bréme, and to have mixed them with determinate proportions of hydrogen. 2. Hydriodic acid gas, and sulphuretted and phosphuretted hydrogen gases are decomposed by brome, which is changed into hydrobromic acid, by separating the vapours of iodine, sulphur, and phosphorus ; this decomposition is always effected with the disengagement of heat. The volume of gas does not sensibly alter when hydriodic acid gas is decomposed by brome; and it increases, when the decomposition of sulphuretted and phosphuretted hydrogen, is effected by it. Brome acts in the same way upon these com- New Series, vou. x11. 2 ¢ 386 M. Balard, on a peculiar Substance in Sea Water. [Nov. pounds of hydrogen when they are dissolved in water, and hy- drobromic acid is formed at their expense. 8. Hydrobromic acid may be procured by decomposing the cubic crystals of bréme and potash with sulphuric acid, but the gas so obtained is often mixed with a small quantity of sul- phurous and muriatic acid gases, which prevents the employ- ment of this method when the hydrobromie acid is wanted per- fectly pure. 3 bs 8) ef 4. To obtain this acid in a state of purity, I had recourse to a process, borrowed to a certain extent from that which is em- ployed for the preparation of hydriodic acid gas. Bréme and phosphorus when put together and moistened with a few drops of water, give out an abundance of hydrobromic acid gas, which may be received-over mercury. : Hydrobromic acid gas is colourless, its taste is quite acid. When exposed to the air it exhales white vapours, which are denser than those produced in the same way from muriatie acid. These vapours have a very penetrating smell, and occasion vio- lent coughing. ISSN ta itd Hydrobromic acid is not decomposed when it is’ passed through a red hot tube of glass; nor does it suffer decom- position if previously mixed with oxygen, and then passed through the red hot tube, nor is any effect produced by putting a taper inthe mixture. se OUT Gates aS On the other hand, bréme does not appear to be capable of decomposing water, as chlorine does. . I did not find either that oxygen was disengaged, or hydrobromic acid formed, by passing brome and the vapour of water through a red hot glass tubé. Hydrobromic acid is decomposable by chlorine, which, uniting with its hydrogen, produces immediately abundant orange red. vapours, and a deposition of small drops of brdme. In ope- rating over mercury these drops are soon absorbed by the — metal, and the gaseous matter which remains after the action possesses. all the characters of muriatic acid. Certain metals also decompose hydrobromic avid gas. It eee that when it was pure, mercury did not occasion any alteration; but. tin and potassium decomposed it entirely, the first at a moderately high, and the latter at the usual temperature. A fragment of potassium passed into a graduated tube full of this gas loses its metallic brilliancy in a few seconds, and is converted into a white matter which gives out bréme by the action of chlo- rine; the volume of the gas is exactly reduced to one half in this experiment, and the residual gas is hydrogen; according to this experiment hydrobromic acid gas is similarly constituted to hydriodic and muriatic acid gases ; that is to say, it is formed of equal volumes of hydrogen gas and the vapour of brome, _ without either increase or diminution of yolume. # 1826.] Proceedings of Philosophical Societies. — 387 Hydrobromic acid gas is very solublé in water: thé solution may be prepared, either by treating a solution of sulphuretted ‘ hydrogen with brome, or by causing the acid gas disengaged by any of the processes described to pass into water; the solution becomes hot, increases in volume, acquires great density, and the property of exhaling white vapours when exposed to the air: when properly prepared, this solution is colourless ; but if the hydrobromic acid gas is mixed with vapour of bréme, the solution becomes of a deep orange-red colour. It may have this colour imparted to it by shaking the solution with bréme, and it dissolves more of it than equal volumes of water. This solution may be termed bromated hydrobromic acid; if it be heated, vapours of brémeand hydrobromic acid are both evolved, and a solution of acid remains which is nearly colourless, but less concentrated. | bi) ‘Chlorine immediately decomposes solution of hydrobromic acid, and gives it.a tint .of uncombined brome ; nitric acid acts upon hydrobromic acid less suddenly, but with more energy as -800n a8 ré-action has commenced; much bréme is produced, and probably water and nitrous acid; a fluid is obtained analo- gous to aqua regia, and which dissolves gold and platina. Sul- phuric acid possesses toa certain extent the power of decom- posing hydrobromic acid; so that it is not uncommon, when this gas is evolved by means of sulphuric acid, to see vapours of brome and sulphurous acid formed by a re-action, the cause of which will be easily understood. (To be continued.) ee eee Articte XIV, Proceedings of Philosophical Societies. MEDICOsBOTANICAL SOCIETY OF LONDON. Tue First General Meeting of this Society was holden on _ Friday, the 18th of October, at eight o’clock, p.m. Sir James M‘Gregor, Director General of the Army Medical Board, Presi- dent, in the Chair, _ After the usual business of the Society had been gone through, a letter from his Royal Highness the Duke of Clarence was read, desiring his name to be added as an Honorary Patron, and Ng that his residence at Bushey Park excluded the possibility of his attendance that evening. The Director (Mr. Frost) then delivered his Oration, in which he congratulated the Society on the rapid advance it had made during the last Session, and the great benefit it had derived from the unwearied zeal which many of its members exerted in its behalf. He also informed the meeting that their distin- 2c2 388 Scientific Notices—Chemistry. {Nov. guished President had lately ordered “that no person shall be admitted to an examination to qualify him to practise in, the medical department of the army without having attended, amongst other branches of science, lectures on botany for six months ;” the salutary effects of which regulation would, in a few years, demonstrate its utility. ins Sir James rose to address the meeting, and assured them that he was but performing his duty in enforcing the regulation just mentioned, or any other of a similar kind, which might, in any degree, be conducive to the extension of practical and useful knowledge in that department with the direction. of which he had been entrusted, and concluded by moving that the thanks of the Society be given to the Director, and that he be requested to make his excellent Oration more public, _ 13 Dow The Chevalier Castillo, Consul-General in London for Spain, was introduced, and admitted as a Foreign Member of the Society. h ybite Several letters from distinguished foreigners were read, among whom were Baron Humboldt, Baron Ferussac,. Mr. Wyttenbach; and Mr. Jacquin, whose diploma of Honorary _>Member was intrusted by the President to Mr, Vivenot, of Vienna. . ; -curshgr: A communication from his Majesty’s Vice-Consul for Guati- mala, Mr. Schenly, was read, and the meeting adjourned to Friday the 10th day of Nov. 1826. : bie ett, ARTICLE XV. - , SCIENTIFIC NOTICES. * CHEMISTRY. 1. On the Confinement of Dry Gases over Mercury. The results of an experiment made by Mr. Faraday, and quated as such, having been deemed of sufficient interest to be oubted, he has been induced to repeat it, and though the origi- nal experiment was not published by him, he is inclined to put the latter and more careful one upon record, because. of the strong illustration it affords of the difficulty of confining dry gases over mercury alone. Two volumes of hydrogen. gas were mixed with one volume of oxygen gas, in a jar over the mercu- rial trough, and fused chloride of lime introduced, for the pur- pose of removing hygrometric water. Three glass-bottles, of about three ounces capacity each, were selected for the accuracy with which their glass stoppers had been ground into them ; they were well cleaned and dried, no grease being allowed upon the stopper. The mixture of gases was transferred into these bottles over the mercurial trough, until they were about four- 1826.] | Scientific Notices—Chemistry. 389° fifths full, the rest of the space being occupied by the mercury. The. stoppers were then replaced as tightly as could be, the bottles put into glasses in an inverted position, and mercury poured round the stoppers and necks, until it rose considerably above them, though not quite so high as the level of the mer- cury within. Thus arranged they were put into a cupboard, which happened to be dark, and were sealed up. This was done on June 28, 1825, and on September 15, 1826, after a lapse of fifteen months, they were examined. The seals were unbroken, and the bottles found exactly as they were left, the mercury still being higher on the inside than the outside. One of them was taken to the mercurial trough, and part of its gaseous con- tents transferred ; upon examination it proved to be common air, no traces of the original mixture of oxygen and hydrogen remaining in the bottle. A second was examined. in the same manner ; it proved to contain an explosive mixture. A portion of the gas introduced into a tube with a piece of spongy platina caused dull ignition of the platina; no explosion took place, but a diminution to rather less than one-half. The residue supported combustion a little better than common air. It would appear, therefore, that nearly a half of the mixture of oxygen and hydro- fen had escaped from it, and been replaced by common air. ‘he third bottle, examined in a similar manner, yielded also an explosive mixture, and upon trial was found to contain nearly two-fifths of a mixture ed oxygen and hydrogen, the rest being a very little better in oxygen thancommon air. __ There is no good reason for supposing that this capability of escape between glass and mercury is confined to the mixture here experimented with ; probably every other gas, having no action onthe mercury or the glass, would have made its way out in the same manner. There is every reason for believing that a small quantity of grease round the stoppers would have made them perfectly. tight.—(Journ. of Science.) : 2. Cafein. | | M. Gatot adopts the following method of preparing this sub- stance :—A quantity of bruised raw coffee was twice infused in boiling water: the brown liquors, when cold, were mixed ; on the addition of a solution of acetate of lead, a very abundant precipitate of a pistacio green colour was obtained. The liquor after filtration was yellowish, but after separating the excess of acetate of lead by means of sulphuretted hydrogen, it became nearly colourless; the free acid remaining in solution was satu- rated by ammonia, and by careful evaporation, crystals of cafein are obtained, which, by purification, were procured in colourless silky crystals. It: appears by these experiments, that the colour. ing and extractive matter of the’ coffee are precipitated by the 390 Scientific NoticesChemisiry. [Nov. oxide of lead, while the cafein, not combining with it, crystal- lizes afterwards from the filtered infusion.—(Journal de Pharm.) 3, Iodine found in the Mineral Spring of Bonnington, near Leith. (Extract of a Letter to Prof. Jameson from Dr, Tucker.) .+ «+The Bonnington mineral water, in addition to the other substances hitherto discovered in it, contains iodine, which may be readily detected by the following method :—Evyaporate a pint of the water to dryness; take up the soluble parts in a drachm or two of a diluted solution of starch quite cold, and add a few drops of concentrated sulphuric acid; the characteristic blue colour will then make its appearance. I prefer the use of sulphuric to nitric acid or chlorine for decomposing the hydrio- dic acid, for it effects that object with carey, and does not decompose the iodole of starch, or prevent its formation, as the last two are apt to do. : : The greater part of the iron in the Bonnington water is under the form of the carbonate of iron, which is held in solution b carbonic acid, It also contains the muriatic and sulphuric acids in combination with lime, magnesia, and soda; the last of which is the predominating base. Potash is also present, and forms the hydriodate of potash with the hydriodic acid. Its quantity, however, is more than sufficient for saturating that acid ; for the residual salts still contain it after the hydriodate of potash has been removed by alcohol. | I have examined portions of water, the springs of Harrowgate, Moffat, and Pitcaithly, but could discover in them no trace of iodine...,.. (Edin. New Phil, Journ.) 4. Fluidity of Sulphur at common Temperatures, Mr. Faraday having placed a Florence flask containing sulphur upon a hot sand-bath, it was left to itself. Next morning the bath being cold, it was found that the flask had broken, and in con- sequence of the sulphur running out, nearly the whole of it had disappeared. The flask being Bisken open, was examined, and was found lined with a sulphur dew, consisting of large and small globules intermixed. The greater number of these, per- haps. two thirds, were in the usual opaque solid state; the remain- der were fluid, although the temperature had been for some hours that of the atmosphere. On touching one of these drops, it immediately became solid, crystalline, and opaque, assuming the ordinary state of sulphur, and perfectly resembling the others im appearance. This took place very rapidly, so that it was hardly possible to apply a wire or other body to the drops quick enough to derange the form before solidity had been acquired ; by quick motion, however, it might be effected, and by passing the finger over them, a sort of smear could be 1826,] Scientific Notices--~Mineralogy. | 391 produced, Whether touched by metal, glass; wood, or the skin, the. change, seemed equally rapid; but it appeared to require actual contact ; no vibration of the glass on which the globules ; lay, rendered them solid, and many of them were retained for a week in their fluid state. This state of the sulphur appears evidently to be analogous to that of water cooled in a quiescent state below its freezing point ; and the same property is also exhibited by some other bodies, but I believe no instance is known where the difference between the usual point of fluidity and that which could thus be obtained is so great: it, in the presen instance, amounts to 130°, and it might probably have een rendered greater if artificial cold had been applied.— (Journal of Science.) : | 5. Detection of Arsenic. The following “elegant, test of the precise nature of the metallic crust (viz. that obtained by Dr. Christison’s method of detecting arsenic) when its quantity is too minute for its physi- cal characters to be unequivocally ascertained, was communi- cated to Dr. Christison by Dr. Turner, Lecturer on Chemistry in Edinburgh. It consists in chasing the crust. up and down the tube by heat till it is all oxidated; when it assumes the appear- ance of, sparkling crystals, which may be ascertained by a micro- scope of four powers to be octohedra.”—(Extract, from Edin. New Phil. Journ.) : | < sehiwsrice MINERALOGY. 6. Analysis of Halloyite, : This mineral has been analysed by M. Berthier, it is found at Angleure, near Liége ; it occurs in kidney form, or tubercular: masses larger than the fist, among the ores of iron, zinc, and lead, which occupy the cavities of the transition limestone of the north, and which are especially so common in the provinces of Li¢ge and Namur. M. Omalius d’Halloy is the first. who noticed. it some years. since; mineralogists will therefore un- doubtedly approve the name given to this substance, as that. of a philosopher who. has so. greatly contributed to the study of geology. | Pre Halloylite. is compact, its, fracture is the waxy conchoidal ; nig be indented by the nail and polished by rubbing with the finger; its colour is pure white or white. slightly shaded with greyish blue; it is transparent at the edges, and adheres strongly to the tongue. When small pieces are put into water it, becomes transparent like hydrophane ; air is given out, and its weight is increased about one-fifth, By calcination it loses 0:265 to 0:280 of water, becomes very hard and milk white. . _ If it be powdered and. exposed for some time toa temperature of nearly 212°, it loses water, for after that it does not lose more 392) Scientific Notices— Zoology. [Nov. than 0:16 by calcination. The powder dried, but not calcined, rapidly absorbs. water when put into it, or when it is left exposed: to moist air. Sulphuric acid readily acts ‘upon ‘it, even edlds: it separates gelatinous silica, which dissolves perfectly {in thie - alkalies. By analysis after drying in a stove it yieldedy!) 6-11! ©. Silica. 050,918, 0,¢ OP © Of OF9 0.0018, e.g OOO eLe.g 44:94 Ligk | Alumina, ee ee my ee eee. 39-06 ( 4 ii ; : Water. erme seer err weer ener ee es ener 16-00 1 Vg yi wie | € 10000 ~The alumina contained a little iron, which renders it probable : that the blue tint of the mineral ae be owing to the presence. _ of phosphate of iron.—(Annales de Chimie.) li Hoang 7. Cold produced by Combination of Metals: <0: According to M. Dobereiner, when 118 parts of tin, 207 of lead, 284 of bismuth, and 1617 of mercury were mixed at the temperature of about 65° Fahr. it immediately fell to 14°.— (Ibid.) | me pa Fe 5s! UT Fe | Zoo.oey. 8. Notice on the Digestive Organs of the Geseigs \Comataaes oF Lamarck, and on the Crinoidea of Miller. By J.E, Gray, Esq. FGS. with WSF. acl lately occasion: to examine a-specimen of Comatula reserved in spirits, I was struck by observing that the proboscis- ike tube described by Peron, Lamarck, Miller, &c. as: the mouth of this animal, was not situated in the centre of the body, but at an intermediate distance between the: centre ‘and the- margin, on‘the: smooth place intermediate between the ‘arms. On examining the centre, I found a distinct, rather large, aper- ture, which certainly led on to the intestinal cavity. Now from the situation of the latter opening, which is similar to the mouth of Asterias, and from its form, I am inclined to consider it as the mouth. This hole could only have escaped the view of the’ above-quoted authors by their having examined dried specimens only. This central aperture is pentagonal, surrounded by a fringe which diverges at its angles, sending out: towards ‘the margin, and dividing before it reaches the edge so as to give a’ double fringe-line to each arm, which extends up its centre, and’ sends off a process to the inner edge of each of the fingers, so as to ciliate their inner edge. This continuation of the abdominal integuments is doubtlessly intended for the motion of the arms. I was not enabled to examine the internal structure of the'speci- men, so that I'cannot speak with certainty with regard to the’ uses of this aperture, but the central one did not appear to be provided with any teeth. The tubular process is contracted at’. 1826:} Scientific Notices—-Zoology. —§ 363% its end;':and) furnished with 10 small short filiform tentacula ; and upom blowing with a tube into the central one, the cavity of the abdomen was-dilated, and the air came out of the tube. - Mr. Miller, in his description of the genus Comatula, appears to have only-examined a dried species of the genus, and to have taken his account of the mouth from Lamarck, as he compares’ it with the mouth of the Crinoidea, which evidently appears to belong'to the same group; but he describes the mouth of that: family as being “ able to be'protruded into the form of an elon- gated proboscis.” wha On consulting the abdominal integuments of the specimen’ formerly belonging to Mr. Tobin, now in the British Museum, of Pentacrinus Asteria, Koenig, (the P. Caput Meduse of Muller, figured by Muller, in-his Crustacea, Plate 2, f. 8, it very nearly agrees with the abdominal surface of the Comatul, and the part’ marked z in the figure is the true mouth, but I could not discover’ any traces of the tubular vent; and on examining the pelvis of the specimens of the fossil species of Crinoidea in the same collection, I was equally at a loss to discover any traces of the latter part; and the central or subcentral hole (mouth) in several of the specimens, appears to be produced into a kind of proboscis ; but sometimes that part itself is difficult to discover, ‘so that I am not, from the apparent absence of the part, perfectly ‘convinced that it does not exist in the recent animal. I may also observe, that there is no trace in the fossil species, of the _ radiating muscular lines which surround the mouth of the Coma- tule. ) | The Comatule, on account of their possessing a double aperture to their digestive organs, should certainly be separated from the Asterotda or the Asterie of Linné; and as they so greatly resemble the only recent species of Crinozdea at present. known, I should certainly place them in the latter family, till specimens of the latter can be observed alive, or which have been kept in spirits, so that the absence or presence of the second aperture may be distinctly traced. : The foregoing observation was made on a specimen of Come- tula Mediterranea of Lamarck, which appears to be the C. fim- - briata of Miller, which is certainly distinct from the C. fimbriata: of Lamarck ; but since that time, having had an opportunity of _ examining C. carinata, Lamarck, or a very closely allied species, I find nearly the same structure, but that the tubular proboscis is bent down towards the centre as if by a suture, so that the openings are very close together, and the muscular ridges are: stronger both on the abdominal integument and on the fingers ; and it appears to be this part which forms the fringe of them : I) may’ also add, that from the examination of a very mutilated specimen of this genus, the abdominal cavity ,is 304 New, Scientific Books, : [Nov. extended to the internal concavity of the crustaceous plate, to which the dorsal arms. are attached, in the same manner as it is produced down the stem of the Encrinus, so that there appease. every reason to believe that this genus, and the Crinomdea’o Miller, should form one family, to which the name of Encrinide might be attached, on the right of priority.. ° | hile on the subject of the star-like animals, 1 may remark, that after examining numerons specimens of Ophiura at Euryale, preserved in spirits, I have not been able to find any provided with the corpus spongiosus of Spix, and this, together with their want of Ambulacra on the lower surface of the rays, for the assage of the sucker, incline me to form them together into a - amily under the name of Ophiuride, and to, leave only the genus Asterias of Lamarck, which is capable of being separated into two. or three groups, as the family Asteriade, whose habits and manners of living differ greatly from the former family, 9. Splendid Collection of Shells, We are happy to announce that a further opportunity of becoming possessed of specimens from the splendid collection of shells, formed by the late Earl of Tankervyille, is about to be offered to the public, -This matchless collection, together with alarge addition from several other collections, consisting in the whole- of about 4000 species, and more than 40,000 specimens, will soon be brought forward for sale, by public auction, by Mp. G, B. Sowerby. _ , Ws i at | The collections may be seen at 156, Regent-street, where also. may be obtained copies of a plan for the disposal of them, affording peculiar advantages to naturalists and scientific collectors. — " : ate ArTICLE XVI. NEW SCIENTIFIC BOOKS. PREPARING FOR PUBLICATION, Elements of Logic, containing the substance of the article on that subject, in the Encyclopedia Metropolitana ; by the Rey, R, Whately, DD." . ; A Treatise on the Steam-Engine, Historical, Practical, and Descrip- tive; by John Farey, Engineer. Illustrated by numerous engravings, by the late Mr. Lowry. . A Personal Narrative of a Journey from India to England, by Bas- sorah, Bagdad, the Ruins of Babylon, &c. in the Year 1824. By Capt. the Hon. G. Keppel. A Sequel to the. Diversions of Purley; containing an Essay on English Verbs, with Remarks on Mr, Tooke’s Work, and on, some Terms employed to denote Soul or Spirit; by John Barclay. _. 1826.] New Patents, 395 On Galvanism, with Observations on its Chymical Properties and Medical Efficacy in Chronic Diseases, with Practical Illustrations. Also Remarks on some Auxiliary Remedies, with Plates; by M. La Beaume. JUST PUBLISHED. An Essay upon the War Galleys of the Ancients; by John Howell. 8vo.. With 11 Plates. 5s. hf WP's _ Mathematics practically applied to the Useful and Fine Arts; by Baron C. Dupin: adapted to the State of the Arts in England, by George Birkbeck, MD. No.I. 1s. Lardner’s Trigonometry... 8vo. 12s. Areas of Circles. 12mo. 3s. a Hooper onthe Brain. 4to. 2/. 12s. 6d. | net Collections from the unpublished Writings of the late C. H. Parry, MD. 2 vols. royal 8vo. 11. 192s. a ha , Plain Adyice for all Classes of Deaf Persons, the Deaf.and Dumb, &c. 5s. . | ge ? ay dla | ArticLe XVII, NEW PATENTS. | T. R. Williams, Norfolk-street, Strand, for an improved method of ie ag si hats and caps with the assistance of machinery.— ept. 18. | eo] y R. Chard, Somersetshire, lace-manufacturer, for improvements Z machinery for making net, commonly called bobbin or twist-net.— ct. 4. .- ‘ F. Halliday, Ham, for certain improvements or apparatus.used. in drawing boots on and off.—Oct. 4. ie : T. Jones, Coleman-street, accountant, for an improvement on wheels for carriages.—Oct. 11. | W. Mills, Hazelhouse, Bisley, Gloucestershire, for an improvement in fire-arms.—Oct. 18. . ' ‘4 W. Church, Birmingham, for improvements in printing. —Oct. 18. S. Pratt, New Bond-street, camp equipage manufacturer, for im- provements on beds, bedsteads, couches, seats, and other articles of furniture.—Oct. 18. W. Busk, Broad-street, for improvements in propelling boats and ships, or other vessels, or floating bodies.—Oct. 18. J. Piney, Shanklen, Isle of Wight, and G. Pocock, Bristol, for improvements in the construction of carts or other carriages, and the application of a power hitherto unused for that purpose to draw the same, which power is also applicable to the drawing of ships and other anag. and for raising weights, and for other useful purposes.— ct. 18. 396° Mr. Giddy’s Meteorological Journal. (Nov. Articte XVIII. ; Extracts from the Meteorological Journal kept at the Apartments of _ the Royal Geological Society of Cornwall, Penzance. By Mr. E. C, Giddy, Curator. peponel py ae BaroMeEter. Reais. THERM. |Rain in 1826. , —!100 off Winp. REMARKS, — Max. | Min. | Mean, |Max.|Min.) Mean. jinches. ¥ Sept.25] 29°86} 29°60 29°730| 65 | 58: | 61-5 |. SE [Cloudy ;. showers. 24] 29°48}. 29°44 29-460) 64 | 58 | 61-0 ‘S$ __|Showers, 25] 29-40} 29°30 29°350| 66 | 58 | 62:0 | 0-150} § " 26] 29°58| 29°50 29°540| 65 | 58 | 61-5 SW |Fair. 271 29-40! 29°80 |29°350) 66 | 57 | 61-5 | 0200} SW |Rain. 28] 29-98] 29°66 29°820| 65 | 56 | 60-5 SW Cloudy. 29] 29-60| 29°44 29-520] 66 | 55.| 60-5 |. SW |Showers 30] 29°55} 29°50 29°525| 66 | 58 | 62-0 | 0-060) SW Fair. Oct» 1} 29°64] 29°60 29-620} 60.| 52] 56-0 N_|Clear, 2] 29°78] 29-76 29-770) 62 | 54} 58-0 NW |Clear, 3| 29-70} 29°68 29°690/ 63 | 51 | 57-0 NW |Clear; showers. 4| 29-70| 29°68 '29°690} 62 | 52 | 57-0 NW |Clear. 5] 29°76] 29-70 |29°730| 62 | 53 | 575 | W = |Clear; showers. 29°86} 29°84 |29°850| 61 | 48 | 54-5 NW |Fair. 29°80} 29°79 29795} 61 |/52 | 565 | 0220] SW |Fair 5° showers: 29°73| 29°66 29°695| 62 | 51 | 565 SW (Showers, - 9} 29-66} 29°66 29-660] 62 | 52 |. 5701 -. |. SW. |Showers. _ 10} 29°70}, 29°66 29-680} 63 | 52 | 57-5 | W_|Showers... > | 11} 29-90] 29:90 29-900! 64 | 52 | 58-0 | 0300] W = ‘Showers. - 12] 29-90] 29-90 '29:900) 65 | 58 | 61-5 W Fair; showers. 13} '29-88 | 29°88 |29-880} 64/58} 61-0} © | SW |Misty rain, 14} 29°88} 29°88 '29°880| 64 | 58 | 61-0 SW (Fair. 15) 29°60} 29°50 |29°550| 62 | 58 | 60:0 S$ |Fair 16; 29°50] 29°33 /29°415| 60 | 54) 570} | | SW [Fair ; clear. 17| 29°60} 29°60 |29°600| 60 | 50} 55°0 SE /|Fair. . 18) 29°58] 29-58 |29°580| 62 | 48} 55:0. SE |Fair ; showers. -19| 29°56} 29°54 29°550| 63 | 54] 58°5 SE |Fair; clear, 20| 29-56 | 29°54 |29°550| 64 | 56 | 600 SE. |Fair. 9i} 29-56] .29°55 |29°555| 64 | 56 | 60-0 S. |Fair. 29] 29-60} 29-60 |29°600) 64 | 57 | 605 | 0-100} S jClear. 29-98 | 29°30 |29°650| 66 | 48} 59:0] 1:03 | SW RESULTS. Barometer, méanh height ee eeeseae smavesccegeashe 29°650 Register Thermometer, ditto .......seeeseeese+ 59°09 ‘Rain, No. 1, 1030, No.2, 2:950. Prevailing wind, SW. No. 1. This rain guage is fixed on the top of the Museum of the Royal Geological Society of Cornwall, 45 feet above the ground, and 143 above the level of the sea. No. 2, Close to the ground, 90 feet above the level of the sea. Penzance, Oct. 23, 1826. EDWARD C. GIDDY. . 1826;] ‘Mr, Howard’s Metéorological Journal. 397 ARTICLE XIX. ia METEOROLOGICAL TABLE. ee ie yi - BARromerenr... ‘THERMOMETER.|| |_|. . 1826, | Wind.}| Max. Min. _| Max. |° Min.» |, Evap- | Rain.-. 8th Mon.}. a cSt, oleh tok I ; ied Aug. INE} 80°18) } ° 30°12" | 85) F620} ome fh ere QIN? OE) 80°12: -}) 8006.9) Bhd) GLO tom ~— 3IN W\| 30:09 30°06 81 | 60 | — 92 4N E| 30°14 30°09 77 59 _ 32 SIN. E| 3019 30°14 | 74 | 50.) — 6iIN W 30:28 30°19 77 56 nee 7iIN Wi 30°28 30°23 78 59 _ “SIS Wi 30°23 30°13 |. 85 55 —_ 9N Wi 30:13 | 30:10 | 81 59 a — 10\N E| 30:10 30°04 80 | 55 — ~_ 11S W, 3015 30°03 66 | 48 _ 35 12\N _ W|.. 30°38. | $0:15,| 71 | 46 | — 13/S ** E| 30:33 | 30°11 | 78 ‘|: 46 “| 1-89 1458 Wi 30:20 | 30-11 80 | 50 | — ai 15S W 3020 | 3010 |} 75 | 52 fom poe 16iN Wi 30°23 30°11 73 7) OO We oes 17IN W) $042 | 30°23° 1°74 | 60 | — 18iS W)| 30°43 30°42 81 52 | — 19} E, 30°43 30:18 84 [BB fell Ve fomcmod? 20| E 30°18 30°09 | 88 | 57 | — 21\N >: E}-- 80°09° |} 30°06" «|: ‘77° toy fala Sahelian 22'S E} 30°06 29°97 “79 57 — 23\5 “Wl 29'97°'|° 29°85 | 76°) 58°, — — 24); We} 29°89.) 2986) 76-1 61. |e, nied 2555 Wi 29:90 | 29°89 | 80 | 60 | — 20 26\8 W| 30:08 29:90 | 74 54: ‘92 7| W | 30:14 30°08 73 50 | — 98iS E} 30°14 30:08 78 64 | — 29|\N° W| 30:08 29°88 80 | 58 — 308 E} 29:93 29°88 73 | 56 | — 3118 Wi 29:93 29-92 75 | 57 ‘89 | 08 “| 3043 | 29°85 | 88 | 46 | 414] 1872 The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column. A dash denotes that the result is included in the next following observation. 398 ‘Mv Howars MeléorélogiealJoivnal. [NOW REMARKS, Eighth Month—1, Sultry, 2. Fine. 3; Overcast: a heavy storm about mid. night. 4. Rainy night. 5—8. Fine. 9. Fine day: some‘rain at night, 10. Fine. 11, Rainy, 12—19. Fine. 20. Sultry. 21, 22, Fine. 23, Cloudy. 24, Fine. 25. Fine day: the sky became suddenly ovetcast about seveny p. mij and @ violent, storm followed, accompanied with incessant lightning for two or thtee hous, 26—31. Fine. \ _ RESULTS. Winds: NE, 6; B, 2; SE, 45 SW, 9; W,2; Nw,.8. Barometer : Mean height | For the DON. .s.sssdesevecciveccccscesensenaress 30°109 inches Thermometer ¢ Meén height For the MONA 048 - s'de s Gubadees cer spgneunesitbee. 66°725° Evaporation. ..ss0cvcovevccscvesvecsecscosecccdccevececcssvepecs 41d fn. Res Sa ST ee oa ERC is Pech es PR hc ia TORR: 1°87 Laboratory, Stratford, Tenth Month, 24, 1826, R. HOWARD. 1826.] Mr, Howard’s Meteorological Journal, 399 METEOROLOGIGAL TABLE. ance igen 4 Barometer. ‘Euermomeéter. . : 1826, | Wind. | Max. Min... | Max: | Min. | Evap. | Rain. 9th Mon. 9 oe : Sept. IN W] 99°92 | 9986 | 76 | 57 | — 09 2S Wi 29°25 29°86 65 60 — 30 3| E 30:06 29:95 70 | 51 _ 4) § 30°06 30:05 76 50 — 15 5IN WI 30°05 29°65 68 50 — 53 6S El 2965 29-32 68 53 — 42 1S EE} 29°78 29°65 58 49) — 19 sis Wi 29:90 29°78 71 51 — 49 9 E 30°15 29:90 | 62 57 ne 10S Wi 30:33 30°15 64. | 54 — 11IN W| .30:35 30°33 |. 64 44 — 12IN W| 30°35 30:20 68 46 13} W 30-20 30°05 67 48 “+87 14+ W 30°36 30°05 68 44) — 13. ISIN E] 30-41 30°36 | 68 46 _ 16 E 30°41 30°11 68 40 —- : if} © 30°11 | 29-98 73 52 — 14 18iN _E} 30-02 29-98 68 60 — 34 19} S 30°02 29:98 72 59 _ 20N FE! 30°16 30°02 65 48 _ 21N.. El] 30°28 3016 66 4.0 — | 92| E 30°28 30°20 61 32 — 93| EB 30°20 30°00 74 48 — 24\5 Ej} 30°00 2984: 70 4A ‘90 13 25, S 29°95 29°84: 70 39 — 15 26} S 30°04 | 29°95 70 63 | — 35 27IN Wi 30°28 30:04: 68 | 46 — 2818 Wi 30°28 30°24 72 52 _ 29S - E} 30°24 29:93 72 55 — 30| S 29°96 29:91 72 52 78 02 30°41 29:32 | 76 "|. 82 1 255 1 3:48 The observations in-each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column, - the result is included in the next following observation. A dash denotes that A400 Mr, Howard’s Meteorological Journal, [Nov.1826. : } ¢chetnka FT TH I ~ Ninth Month.—1. Fine. 2. Rainy. 8, Cloudy.» A. Lcgren ve evening, 5. A shower at twelve, am. 6—8. Rainy. 9—13. Fine. 14, Rainy afternoon, 15—17. Fine. 18. Rainy. 1923; Fine. 24—26, Mornings rainy : afternoons \ fine. 27. Fine. 29. Foggy morning : fine day. 4 30, PeRAY 19 Sindy sciaite EM g 2 . Pak ABET : nr, lo sh Ys hgh 2. agrorigy dik al ~ WO Des) QasecosriGkak 1 ena ‘he 3 Bia) is j tae eo. on NOdsBS F: re Ys NT, viele | # et xe end ; : dT wt i H i) 4 j new le dl hi 6! Bnrgne! pa \ | anno b Gilwusuen if 4 i b3 - i bcqenop shh njopde eb: etosislgtna WT th | 4 me ledangac:laigaboe Wi seestay/oink bingy . § yeti *® “Wats: NE, 45,6; SB, 4; 8 5 om dad ba sisal Baroni Mean height 1 | QO bit AE nto? ¢ Stet- ; cf yetke ‘ re “ Sheshied ; ar kg + For the Rey saarinsiran ET ; ph pephnd “odie Bes: | $f Vedd sa Teemonetes ‘Mean height, EE te eee ee ee, Ratgi } , . Sag ms jleie Pog dabntndh. 2, Jessa ad OE ha ae , i ; , ; 1 a4 & et b Brainy oeeentnteensnaseitenit teint cS Rai one a ae © otek tte 4 cohu¢eem nh Sth tiki sos loth igor Sos 3:43 f }- : e200 bbe Set ob a heeeeih J00rbaes dried alerts me | | : ‘hi , ORI CS 3 Sap egoRt op em BO. | al " GEES. 54 ’ hanSen RA thar! | BO d OR. Ay SGC It gate a ate } pata Bi iit fiiee ‘ * - Hi MARA DRE Gilt bf , ‘4 a3 ats ; Loboratory, Stratford, Tenth Month, 24, 1826. pai R. HOWARD. : J 4 at” i , Ps ide. + ‘ . «) t , 4 Ve yr “f riot a t Bes izan le " nn Reser wee I? ofa Ht piesa? = peeuidere a> vey Be Lied A, “a4 aT dg : 7 ; ANNALS OF PHILOSOPHY. DECEMBER, 1826. ArTIcLE I. On Anhydrous Sul, hate of Soda. By Thomas Thomson, MD. : FRS, Professor of Chemistry, Glasgow. THERE is a manufactory of carbonate of soda near Glasgow, belonging to Mr. Wilson, jun. of Hurlet. The process consists in mutually decomposing protosulphate of iron and common salt. “The sulphate of soda thus produced is decomposed and converted into carbonate of soda in the usual manner. Some- time ago they were in the habit of boiling their saturated leys ; during which part of the process large crystals were observed to form in the inside of the boilers. Mr. William Wilson, bro- ther of the proprietor of the work, got a number of these crystals, and from the circumstances of their formation, he concluded that they must be anhydrous sulphate of soda. He was so obliging as to bring me a few of them that their real nature mig t be ascertained in my laboratory. , ~The crystals were octahedrons with a thombic base of a very large size; many of them measuring about 1°8 inch in length, and 0°8 inch in breadth. They were translucent, but not quite transparent, and the faces were too rough on the surface to admit of measuring the angles by the reflective goniometer. By a number of measurements with the common goniome- ter, the inclination of . Pon P’ is 75° P on P” 140 The first of these is the average of 16 measurements never ‘deviating from each other more than 1°; but the second is the result of one measurement only; for 1 found only a single crystal in which a part of the lower pyramid. was visible. In New Series, vou. Xt, os” aa 402 Dr. Thomson on Anhydrous Sulphate of Soda. {Dec. general, it was totally wanting from the way in which the crys- tals had grouped togethiery or rathetyits faces, in consequence of that circumstance, wefe rehdered sd ‘irregular that nothing could be ascertained respecting the inclination of the faces of the two pyramids on sick other. The large angle of the pyra- mid constituting the edge a was also. measured ; but the measure- ments devigtltl so much from each other that no conclusion could be drawn. I rely much more upon the measurement of the edge a’, because all the different measurements agreed nearly with each other. In some crystals, the face P was much larger than the face P’ making the summit of the pyramid terminate. not in a point) but a ridge: -In some crystals, a four-sided oblique prism was interposed between the two pyramids; but none of these admitted of measuremént. . The crystals were firm and solid, and had a glassy appearance. Wheii exposed to at incipient red héat, they andetwent' nd change. When kept ‘about two moiiths in a dathp press, they had. obviously imbibed moisture ; for there was an efflorescence on their surface. . When these crystals were heated to redness; they lost about one*third of an atom of water (9°36 grains lost 0°30 grain); the effloresced portion became soft and loose, ene could easily be detached from the crystal, leaving the eryst line»hdeleus ‘as perfect.as ever. yj o6 ou) bo ayo yor eho eek _ The specific gravity of these crystals was 2°645, determined ‘op droit them in alcohol. Ina paper printed in the Annals — of Philosophy tor December, 1825 (vol. x. p. 441), ay the Specific gravity of anhydrous sulphate of soda 2:640, This does not-deviaté much from the present determination, The specifie gravity now given has the greatest chance of being covrect, as the crystal weighed was hard and compact, and less liable to any — inaccuracy than the anhydrous powder, from which the’ foriner determination was obtaineds 202 p05) osny 6 Yo sepa oulmors When. the crystals were. exposed to a strong red. heat.in a platinum crucible, they underwent the igneous fusion, and.on cooling concreted into.a foliated brittle saline mass, exactly as — happens to common sulphate of soda in the same circumstances. 100 parts of water, at the temperature of 57° dissolve 10°58 parts cf this salt. When the saturated solution is set aside for some time; crystals of common glauber salt shoot in it abun- dantly. | TF : i The crystals do not affect vegetable blues. _Nine grains of them being dissolved in water, and mixed with a solution of 13-25 grains of chloride of barium, abundance of sulphate of barytes fell down, and, the residual liquid wasmeither rendered muddy by sulphate of soda, nor muriate of barytes. This demonstrates that the acid in this salt is precisely the same, and in the same proportion as in glauber salt, Finally, when this 1826.] Oh the Reaction of Sulphate of Maginesit, &. 403 salt is dissolved in water and crystallized, it yields common crystals of glauber salt to the very last drop. | . ' These experiments leave no doubt that. the salt is really an anhydrous sulphate of soda, as it had been thought to be by Mr. W. Wilson; so that the only difference between it and glauber salt is the absence of all water. . ’ Thus it appears that sulphuric acid and soda are capable of combining and crystallizing without water as well as sulphuric acid and potash. Three distinct species of sulphate of soda are now known to exist. OF 33 1. Anhydrous sulphate, ¢rystallizing in a boiling solution, and crystallizing in octahedrons with rhomboidal bases. dated sulphate of soda, containing 10 atoms water, éerystallizing in a cold solution, and forming crystals which have the shape of doubly oblique four-sided prisms. » 3. Sulphate of soda crystallizing im a supersaturated sclution of sulphate of soda made in a high temperature, and set aside for some days in a well-corked phial. The crystals are opaque, white, four-sided prisms, and contain eight atoms of water instead of ten. The first account of this variety was published by Mr. Faraday. There is a description and analysis of it made some years ago by myself in-one of my common-place-books. ‘Thad forgot the circumstance, till it was brought to my recol lection by Mr. Faraday’s paper, which I saw for the first time — ubout two months ago in a German journal. i j Sdeeeini, ee 3 ‘ fo el r “a Ps aii Ga AE fst atin. 1s: ARE ROI AS sciwoliol ed On. the Reaction of Sulphate of Magnesia and Bicarbonate. of : Soda. By M. Planche.* - Tr is known that the bicarbonate of soda and the sulphate of Magiiesia, in a state of aqueous solution, exercise no reciprocal action in the cold, and that it is only when a certain quantity of carboni¢ acid has been disengaged by heat, or, in other words, when the alkaline bicarbonate has passed into the state of sub- carbonate, that the sulphuric acid prevails over the scda, and leaves‘the magriesia to the carbonic acid. But I have nowbere Seen it mentioned that the two salts mixed together, in a dry state, and in the form of powder, react upon each other. This must at least be the case with regard to their immediate and instantaneous mixture, since in this state they dissolve in water without affecting its transparency, and consequently without any decomposition taking place, or at least any apparent decompo- < From the Jourmal de Phatmacie. 2n2 404 On the Reaction of Sulphate of Magnesia, &e, {Drei sition; Presuming upon. this, property. oft 16, two, salts). ahi: sician: prescribed several years ago, to M,, paiva @ MX- ture of powdered sulphate of magnesia anc Nite § analy of soda. He gave alternately either this mixturéalone or bic are bonate of soda. Being charged with the preparation of both these medicines for a journey of three months, which M. de Sommariva made annually to Italy, I always had the precaution of placing the mixture ina very dry state, and divided into par- cels in tin.canisters, to preserve it from humidity, I used the same precaution with regard to the carbonate of sodaysiiI observed that the sulphate of magnesia was free of kydtochlo- rate. “AR ie am L580 ani0 During three years M. de 8, a man very careful of his*health, and besides a good observer, never perceived that old water became turbid when he dissolved the two, salts together in it; but in 1822, having been obliged to prolon: hie! oti beyond the usual time, he laid up a store for a year.,.Le ie end ofthe fifth .month,, M, de S, remarked, the the. same water which. he. ordinarily used became. slig tly mi ky, a tha , the change which-he, nghtly attributed, t oneD without er aie dovexplain. the. sausys athe SveraHOR OF ie powder, went or snprepsings asthe time, as enc At length, by the’ hia month, ,the precipitate which, formed in the wal er bee ime 'So. considerable, that M. de S. dosioee at eruer to intermit the tse of the powder, and sent for some more, promising to inf rn me, on his return from Italy, of what, according to his ex resi n, had happened. M. de 8. returned at the end of six months, and sent me back the powder in question, which I submitted to the following experiments. | nig 3 heearaas “ _ 1, This powder put into a quantity of cold water, doub ‘that ak is necessary for dissolving the two salts, ren ered: it milky. a Sab eeegr ry Tia RE in a large quantity of water it depaatedts iiblte ponder, which, on being washed several times and. lried,” as ound to. be subcarbonate of magnesia. Phe ere, " The liquor in which this deposit was formed was li id apt being filtered, and was not rendered turbid, either .co 6 hot, by the soluble alkaline subcarbonates. All the acids ‘stronger than, the carbonic disengaged this latter from it. . Lastl y ‘When suitably évaporated, sulphate and carbonate of soda Were obtained, part of the latter of which was in the form of subcar~ bonate. ‘To explain here the presence of the carbonate.of soda it requires to be known that the quantity of bicarbonate mixed with the sulphate of magnesia, was more than sufficient to decompose this latter salt. sea et alaghulza 2403 ’ There results from this observation that the sufficiently ‘pro- longed contact of sulphate of magnesia, and bicarbonate’ of soda 1826] Dr, Prout on Digestion. 405 in a dry state, determines a chemical action similar to that which the ¢6ncurrence of water and heat would produce, afford- ina’ nel dosnt lé of the inaccuracy of the old chemical axiom, Ce ae ¥ int nisi soluta.* | he) 16.10 B00! sti) zim ards diod; 10, aottsisgary ab. ML. dordw senso fonpsos1g 90d Diss eye lash “sq. O1n: bobtvib. fos ARTICLE III. ad} boas s.wiibraue iat (Remarks on certain Observations made by MM. Leuret and oldaassaigne, and Professors Tiedeman and Gmelin, in_ their Works on Digestion recently published; particularly with ‘ Sema catila thes Pogsene: of free Muriatic Acid in the. Stomachs inf Animals, By, W. Prout, MD. ERS, Ht AL T90I92O3 2iigs cows t h hovod y Abo the, Editors of the Annals of Philosophy.) on) deena 97 90 Bie the, ear 23 the Royal Academy of Sciences ‘proposed, — is the subject of their prize esSay, an inquiry into the nature of : ge tpn Meade ‘classes of aninials. Of the eS cn offered themselves no one was’ deemed ‘to have -entirely satisfied the views of the Academy, though two of them besa} - SACS ‘edly : weres¢ sidered worthy of honourable mention, ’‘« The authors Fe DOS SUE 97 1 j {YOM Ae Nomi 4 ‘al iy, welt ate (syn the report) have made a Atey number of experiments, and 7 ave ob ts. For this reason,’ and in con- “si eration of the expensive nature of the researches in ‘which ‘t y engaged, the Academy have adjudged to each the sum of 1500 francs.” The authors of one of the éssays were MM. umsahii Lassaigne, who, I presume, accepted the offer of the , Academy ; Of the other, Professors Tiedeman and Gmelin, of - Heidelburgh. The latter gentlemen seem to have been offended TAR Ss seco of the Academy, refused the above offer, and yy ise their essay themselves.} That of Leuret and Lassaigne ‘has ‘been also published ; { and the object of the present com- Binh auattin is to make some remarks on certain passages in these ne s, in which am myself more immediately concerned ; and first of MM. Leuret and Lassaigne. HIS tained remarkable resu SY 2SIROTI?S ela fi : >In Hier 1'14 of their work, these gentlemen refer to my paper + SRA ME YS ka S32) ‘i 7 . . . ’ publis ed in the Transactions of the Royal Society, on the free ’® "Had not the salts got damp in the course of the seven months ?— Ed. ‘+ Recherches Experimentales Physiologiques et Chemiques sur la Digestion, consi- ' -dérée: dans les, quatre Classes d’Animaux vertébrés. Par Fred. Tiedeman et, Léop. Gme- lin, . Professeurs a l'Université de Heidelberg. Traduites de l’Allemand, par A. J. L. - Jourdan. A Paris, 1826. Of this work only the first volume, containing the mammife. Yous animals, is yet published. I have quoted from ‘the French Translation.» ») 94 ' yo} yRecherches Physiologiques et Chimiques pour servir a l’Histoire de la, Digestion. \Par MM..Leuret et Lassaigne: Ouvrage mentionné honorablement par l’Academie Royale des Sciences, dans sa Séance publique du 20 Juin, 1825, A Paris; 1825. 406 | Dr. Prout on Digestion. {Dxc. muriatic acid met with in the stomachs of animals;*, and. after briefly describing the experiments there related, which they, say they have repeated with nearly similar results, they make the following remarks :—-“ M. Prout, apres avoir supersaturé)aved de la potasse pure la portion du liquide dans lequel il cherche a determiner. toute la quantité d’acide muriatique libre ét com- biné, l’evapore a siccité et le calcine pour détruire la matidre organique. En dissolvantalors le résidu dans l’eau distillée, il estime par le nitrate d’argent la proportion d’acide’ muriatique quwil obtient dans cette expérience. Ici Vauteur n'a pout observé que cette methode vicieuse devait necessaire Yinduire en erreur, car exces de potasse qu'il emploie réagit sur les matiéres azotées pendant la calcination au rouge obscur, et il se ferme du cyanure de potassium et du sous-carbonaté'de potasse, qui constituent en partie avec les muriates Te residu salin; or, comme le cyanure de potassium et le sous-carbonate de potasse précipitent le nitrate d’argent, le précipité que forme ce réactif dans cette circonstance n’est point du ehlorure d’argent pur ; et c’est cependant d’apres son poids que! M, Prout a calculé celui de l’acide muriatique qu’il soupconnait exister a Tetat.de liberté... Les conclusions bs travail de cé. chemiste sont done inexactes.” I confess these remarks surprised me not a little, as | conceived the merest tyro knew how to ob- viate the sources of error here pointed out. I wish these gen- tlemen, therefore, to know (what every chemist might ere taken for granted when it was stated that the experiments ‘were made in the usual manner,”’) that the excess of potas was always supersaturated with nitric acid before the nitrate of silver was employed. 3 ube _L now proceed to make a few remarks on certain passages in the work of Prof. Tiedeman and Gmelin. These gentlemen in their preface, after alluding to some other discoveries in which they had been anticipated by M. Chevreul, proceed to say, « Il en est de méme pour ce qui regarde l’acide hydrochlorique ‘libre (free muriatic acid) trouvé dans le suc gastrique des ani- maux. L’honneur de la premiere decouyerte appartient-a M, Prout. Mais nous [avons faite egalement, sans connaitre ses recherches, au mois de fevrier 1524, en distillant diverses liqueurs stomacales, etce fut seulement un mois apres.que le memoire de M. Prout sur ce objet nous parvint.” While these gentlemen thus confirm the discovery of free muriatic acid in the stomachs of animals, they also state’that they have found two other acids in the same organ, viz. the acecie acid and the butyric acid’; and what Ihave chiefly to observe upon, is, that they seem to wish their readers to believe that I denied the presence of any other acid except the muriatic in the stomach. Now this is by no means * On the Nature of the Acid and Saline Matters usually existing in the Stomachs of Animals, Philos. Trans, 1624 Part I, pe 45. kh este foros 1826.] Dr, Prout on Digestion, 407 the.case. My object in publishing the paper in question was simply, to establish that one important fact, and nothing more; though I confess I then believed, and do still, that the. muriatic acid occurs naturally more frequently, and in reater abundance, in that organ than any other acid; for when I have met with combustible acids (as I have, since my paper was published, in a few instances), these seemed to be rather derived from the food than from the stomach itself, in most instances. So far, however, am I from denying the exist- ence of any other acid in the stomach except the muriatic, that on the contrary I think it exceedingly probable, were the con- tents of the human stomach in particular examined, under all the circumstances of diet and derangement to which it is liable, that many other acids besides the acetic and butyric (of which latter, by the bye, I know nothing) would be found in it. With respect to the /actic acid which has so long figured as an important ingredient in animal fluids, chiefly on the authority of ae I always doubted its existence, and am not there- fore at all surprised that it has proved to be a nonentity. MM. Tiedeman and Gmelin inform us,* that Berzelius himself now admits that he was mistaken, and that in fact what he con- sidered as lactic acid is only disguised acetic acid. [ long to see the grounds on which this justly celebrated chemist has changed his opinion, ! .MM. Tiedeman and Gmelin. make some remarks on the -method I employed for determining the nature and quantity of -acid in the stomach which require to be noticed. This method, _to,a certain extent, they give very accurately, but omit entirely the point of most importance, and which was designed as a checkhupow ithe whole; and then proceed to say that the method is inexact and. imperfect. To render this obvious, it will be neces- sary to repeat the method here, which was as follows: The fluid collected from the stomach was divided into four portions, ** 1. The first of these portions was evaporated to dryness in its natural state, and the residuum burnt in a platinum vessel; the saline matter left was then dissolved in water, and the quantity of muriatic acid present determined by uitrate of silver in the usual manner; the proportion of muriatic acid in union with a fixed alkali was thus determined, 2. Another portion of the original fluid was supersaturated with potash, then evaporated: to dryness and burnt, and the muriatic acid contained in the saline residuum determined as before. In this manner the total quantity of muriatic acid present in the fluid was ascertained. 2 A third portion was exactly neutralized with a solution of potash of known strength, and the quantity required for that pur- pose accurately noticed. This gave the proportion of free acid present ; and by adding this tothe quantity in union with a sa 3 | #* Page 167, 408 Dr. Prout on Digestion” | [Dec. fixed alkali as determined above, and.subtracting the: sumifrom the fotad quantity of muriatic acid present, the proportion of acid in union with ammonia was estimated.,, .But,\as-@ theekoto: this result, the third neutralized portion above-mentioned reds anapo- rated to dryness, and the muriate of ammonia expelled by;heats\and collected. The quantity of muriatic acid this.containetl was then determined as before, and was always found, ta, represent:mearly the quantity of muriate of ammonia as before ‘estimatedy thus proving the general accuracy of the whole experiments; beyond a doubt. 4, The remaining fourth portion, of the otiginal, fluid was reserved for miscellaneous experiments.”, .Now,oin their account of my method, MM, Tiedeman and Gmelin: hawé totally omitted the part in italics, without which, whet, aanionia: is’ present (but not otherwise), the process would)be unsatisfactory, as I well knew, but which entirely removed. the, only,ebjection that could be made to it. I may also here méntions that there was another circumstance which operated, asjja;chedki‘to my results, and which, by some accident, was/omitted im \nay:paper, viz. that the third neutralized portion above-mentioned rémammed neutral after combustion, which, could not, have,|been thebease had the free,acid present, been. of, a, combustible. nature.) This: was a point always particularly, attended to; and on referenceto- my notes, I find that, at the;time,imy) paper was) writteny id instance of the contrary had occurred to mie. Since that tine; however, as hasbeen already mentioned, I have met with wfew' instances, of.the presence of combustible acids in theistomachs of animals. And_here, perhaps, it may not be amiss toomake & few remarks onthe method in question, which seems in general not to have been duly appreciated by chemists. Themiere.deter- mination of the existence of a principle in any compound;:with- ouf.its quantity be at the same time ascertained, is ofteniunsatiss factory; at least the determination of the latter: point corroborates the former in no small degree; for before:theiquan- tity of a substance can be ascertained, it must be obtained perse, orin some well-determined state of combination, cireumstances nesessarily implying a much more complete and: satisfactory jnyestigation than that by mere tests only. My. object, there-! fore, was to, contrive a method, by which both t \ploirts might be determined with precision at the same) time. \\; After: trying a great variety, (for those related are by no means\to be considered as the on/y.experiments made) on the: subject) the one above mentioned was chosen as the best suited to my pur- ‘pose; and, so completely did it seem) to answer the end ‘in view, that had I detailed a// that was. done. besides, which would, have half filled the volume of the Transactions; :Iodo not think that, the point in question ‘would havei beén.a whit better,established.. 1 may, however, mention here, thatamong other means, distillation, as subsequently employed by Mr. 18267} Dr. Prout on Digestion: | 409 Ghildrene and “Messts. Tiedeman and Gmelin, was tried, and With: the sdme results ;‘that is to say, the existence of free itidtiatic’weld Was indicated, but its gwantity could obviously not becthus determined, at least with any thing like accuracy. = isbhavelyet oneor two other points’ on which I shall make a few remarks; and on ‘which the German philosophers have by some means misrepresented me in an extraordinary manner. In @ paper first published by me nine or ten years ago, and subse- qu itlyy)in)1819,with some revisions, in the Annals of Philo- pn somthe digestive process, I have said that “ the contents @ stomachs of animals feeding on vegetable substances, even whencfully digested} and about to pass the pylorus, exhibit no traces‘oftian*albuminous principle ; but the moment they enter the duodenum, “they undergo remarkable changes, not only inctheitdappearancés, but in their properties. These changes appetirito be'chiefly induced by the action of two secreted fluids, ith which*they*there come in contact, and are intimately mixed. These preithe bilé' and-pancreatic juice, on the nature of which weishall' make! cavfew ‘remarks: “The bilé consists chiefly, according ‘toothe’ accurate ‘observations of ‘Berzelius, which, agreé withumy own;° of ‘a large proportion of' water holding in solution a peculiar bitter substance, named the biliary principle, ofthe mucus of the gallbladder, ‘and of the usual salts contained insthe blood;‘and in all’ the fluids secreted from it. ° The proper- ties of ‘the Seah juice [ never could satisfactorily ascer- tain) sbut! it? has usually ‘been considered as analogous to the saliva sand) if this opinion be correct, it may be safely considered asecontaining’ no ‘albumen. ‘The changes produced in the digested alimentary matters by these fluids are evidently of a chemicabinature. A gaseous product is usually evolved; a_ distinctiprecipitation of the biliary principle, in apparent union with some ‘others, chiefly of an excrementitious nature, takes lacey the! mixture becomes neutral, and an albuminous principle ts formedjatleasttraces of this principle appear, which, however, become!rueh’ more distinctly visible at some distance from the ylorus¢?2i) And this is a// I have stated on the subject; but Messrs Tiedéman’ and Gmelin represent me as asserting in genevakjterms; what I never dreamt of, that albumen is solely ormed in the duodenum, and cannot exist in the stomach even if. placed ithere (for' without this latter supposition the following remarks: are unintelligible). “‘ Mais il resulte evidemment (they proceed) denosexperiences faites sur des chiens, des chevaux, et. desiruminans, ‘que quand la nourriture consiste en blanc dauf liquidesouquand tes atimenscontiennent d’albumine,cette substance sé trouvedissoute par le suc gastrique et versée dans le duode- hum! avecle-chyme, sans’eprouver aucun changement. — Nous ne pouvonsdon¢ pas admettre avec Prout quel’albumine se forme dang iy ie wih & oy V8 +e Vol. Xiii, (O. S.) p. 12 and 265, 410 Dr,.Prout on Digestion, [Dec, le duodenum seulment, aux depens des alimens qui ont été dissous dans lestomac, et par l’effet de leur melange, tant avec la bile, qu’avec le suc pancreatique,” I read over these passages seye- ral times with the view of discoyering what connexion they.had with the point in question, or how they bore on it, but. have been unable to discover, I simply asserted that, in a or rene on vegetable substances, the albuminous principle is not deve- oped till the digested matters come. in contact with the bile and pancreatic juice, and nothing more—a fact, by the; bye, which is confirmed by Messrs, Tiedeman and Gmelin; but with respect to the introduction of: albuminous matter into the stomach, this is guite a different case; and I can assure these gentlemen that I never, doubted for a moment af, I had examined the stomach of a dog, or any other animal, after feeding it on albumen, that I should have found traces of this principle, not indeed entirely unchanged, but possessing,.most of its original properties, aide Gets _MM. Tiedeman and Gmelin go on to observe with respect to. the albumen in the duodenum, * S’ils’en trouve beaucoup plus dans le contenu de l’intestin gréle que dans celui de V’estomac, cette circonstance depend du melange de la. masse chymeuse avec le suc pancreatique, dont Prout ne connaissait pas la compo- Sition, et dans lequel nous avons trouvé une grande quantité d’albumine chez le chien, comme chez la brebis et.le cheval.” When my paper was published in 1819, I did not know. the composition of the pancreatic juice, as was then stated, and I regret that I do not know so much about it yet.as 1 could wish, I believe, however, that it contains albumen, and. consequently admit that. some of the albumen found in the duodenum may, be derived from this source, though it is still my decided belief that by far the greater proportion found there under. the circum- stances I have mentioned is derived from the food, and is actually developed on the spot during the series of changes that there take place, and in which the bile and pancreatic juice play an important part. , Notwithstanding these little inaccuracies, which were probably mere oversights, 1 cannot close the present remarks without expressing my high opinion of the value of MM. Tiedeman and Gmelin’s volume. Having gone over most of the ground tra- versed by these ing oe My am well aware of the labour and difficulty of the march; and though we may differ, in some minor particulars, which is not to be wondered at, I am satisfied, as far as we go together, with the general accuracy of their observations. With respect to MM. Leuret and _Lassaigne’s book, I am sorry that I cannot express the same sentiments ; indeed as a work it does not appear.to me to be at,all compar- able with that of the German philosophers, Es ecprigted I am, Gentlemen, your most obedient servant, as | W. Prov. 1826.] On a peculiar Substance contained in Sea Water. 411 ¥ 4 ofr | oak i 39gy9 v Biri dasa lies es Donia aa ArticLE TV. , Menioir' nd peculiar Substance contained in Sea Water. By M. Bala alard, Apothecary and Chemist to the Faculty of Sci- : ences, at Montpelier. it, uogu olde Me eye Lee ete (Concluded from p- 387.) / Currarn metals act upon. liquid hydrobromic acid; iron, zinc, and tin, are dissolved by it with the evolution of hydrogen; meétallic. oxides when put into this acid act differently upon it, the’ greater part of them, the alkalies, the earths, the oxides of iron, and the peroxide.of copper and mercury, form fluid combi- nations which may be regarded as hydrobromates; there. are _ some oxides with which the bydrobromic,acid undergoes double decomposition, and produces water and metallic hydrobromu- vets; such are the protoxide of lead and the oxide of silver. — -\ ‘Those. oxides which contain much oxygen, ,and have no affinity for hydrobromic acid, or which cannot, by.decomposing at, form corresponding bromurets at this high degree of oxida- ‘tion, lose a certain quantity of their oxygen, which determines ‘the decomposition of apart of the hydrobromic acid, and conse- quently there is a disengagement of brome. Theless oxygenated oxide afterwards forms with the acid which escapes decomposi- ‘tion an hydrobromate, ora metallic bromuret.._ It is an action of ‘this kind which is exerted by the peroxides, of lead, antimony, and manganese. The last compound may be employed with ‘hydrobromic. acid to prepare brome ; this method, which resem- bles'that for the preparation of chlorine gas, is easier than that ‘which I have previously described. - gatporatd , It will be observed that brome has less affinity for hydrogen than chlorine has, but itis greater than that of iodine ; hydrogen combines readily with chlorine, but itis more difficult to unite it _ ‘direetly with iodine and brome. Chlorine decomposes water ata -high temperature ; brome and iodine.do not decompose it under ‘similar circumstances. Hydrobromic acid is, decomposed b chlorine, but brome in its turn also decomposes hydriodic acid. ‘The action of metals upon these hydracids leads to the same ‘consequences. The hydriodic acid is decomposed by the action of mercury; pure hydrobromic acid may, on the contrary, be long kept on this metal without undergoing any sensible altera- tion; but at.'a moderate temperature, it begins to be decom- posed by tin, which would have exerted no action upon muriatic acid, Sf ; ~ ‘It results from this unequal affinity, that the properties of hydrobromie acid: are in some degree intermediate between those of muriatic and: hydriodic acids. If it resemble the first by the difficulty with which itis decomposed, .by the united influence 4 412 —- M. Balard on a peculiar Substance : [Dzc. of oxygen atid heat, it resembles, on the other h nd, the, latter by the property which it possesses of heing 2 certain extent, by sulphuric acid, and by its pr lissolwing an excess of brome. | lod) bsepeasaib sie, amnodgn: Phe action of brome upon the metals ly, embles, that ‘which chlorine exerts upon the same _bodies.,,, ny and ‘tin burn by contact with brome, Potassium, evolves; sp, nhyuch ‘heat and light by uniting with it, and so violent a detonation ‘ensues as to break vessels of glass in which the union is ceched, ‘and to project the result of the combination to a distance, . aya ‘The bromurets, which are formed directly with these bodies, rand especially the bromuret of potassium, resemb, ein their ‘appearance and properties those which are obtained | A the ‘metallic oxides are treated with hydrobromie: Paphitis e ‘dry or moist way, after having evaporated theselut $, 0F.ca ed ‘them to crystallize. Their aqueous solutions ,have< ithe ‘operties -of their'respective hydrobromates, These facts render it yery ‘probable that metallic bromurets, like chlorides and in es, are ‘converted into hydrobromates by solution in water, and recipro- ‘cally the hydrobomates are changed -into-bromurets !in passing ‘to the solid ‘state: ‘the-study of huis two orders of compounds «cannot be separated without inconvenience. _ As I have prepared only a few hydrobromates and bromurets, J cannot: give their: general. history.), It is. sufficient to state tfia, * the hydrobromates will be easily recognized by the su whic h they possess of imparting a yellow colour, and_emitting Brom ‘e;’ when’ made to act upon bodies which attract hydrogen strong ‘ly- ‘Such are the chloric and nitric acids, and especia éhiloriie, which explains the use of this last substance An;the separation of brome; as to the bromurets, they are all decom- posed by chlorine with the disengagement of brome...) |... TH CEN ET Bromuret of Potassium. __, a sth ~*'Yemployed several processes for the preparation-of bromuret ‘Of potassium. 1.1 obtained it by immersing the, metal in, the ‘vapour of brome; 2. By decomposing hydrobromic aeid:by it ; 3. By directly i this acid with potash, eyaporating:the ‘solution, and drymg the residuum; 4, The, cubic, crystals ‘obtained by saturating the ethereal solution,,of,-brome,,with poe may be considered either as hydrobromate of potash, or muret of potassium. They always contain small portions,of muriate of potash or soda; in whatever mode the bromuret of tassium is obtained, its toi are always similar, and if it he dissolved in water and recrystallized, it usually assumes a ‘Gibic’ form, and sometimes that of\a long rectangular.parallelo- Pi j/its taste) is) sharp; when, heated, it; decrepitates, and “gindergods igneous fusion, without, suffermg, any Pasagtinth - “ Fitie decomposes it at a high temperature, brome.is evolved,an 1826.) °° contained in Sea Water... - - 413; chlotidé' bf potassium is formed. | Todine does not act upon it, even at*a température ; on the contrary, when brome is: madé td pa 6vér ‘fused iodide of potassium,. abundant violet vapour risen aged ; boracic acid does not decompose. it at a éd at, u ; the vapour of water be passed over the mix- ture ‘and th re: Wheii TO} t into water, it is converted int hae? old, ‘and’ produces a sensible diminution of temperature during S6tufion 3 it is soluble also in alcohol, though sparinely so ;’the*sdlution “of hydrobromate of potash does not dissolve ) ite Bo é ‘than’ pure’ water; the solution is decomposed, by s fn TIC, aC: d, which disengages the vapour of hydrobromie acid, and of bréme.;'1*27'gramme of brome, treated in this manner, le saan ar ecard 173 of sulphate of potash ; this quantity of salt a itis’ 0°52668 of potash, consisting of 0-08927 of oxygen ~ ahd 0'43741 ‘of potassium : according to this experiment; bro mu- SU cP RMLRUAPCobadd of te less non toad qaieesq oiBrome rs. bite @ dole 86s ve eee oo vee eee pit 65°56 . bavogarcPotassium 0 ete le DaDed b 0 eye wep ee wee Be, 34:44 i | 7 FAIS LOSVOOONE 7 ] Wf ose i AsWwMOTd bes esismoyobyd wt ¢ bJigG 100‘00" Loy Supposing this compound té be’ formed of an atomof brome and ani athi Of potassium, thé atomic weight of brome will be 93-26, the atom’ of oxygen being 10s 2 89s) e29% 0G Yom sig '>2Phe ‘inetallic bromurets are converted into neutral, hydrobro- Mime solution in water, which, being decomposed,, the twe 1 Baie ee. combine with the brome,: and the volume Ofdkyben unites with the metal. As hydrobromic acid is. comr posed of equal volumes of hydrogen and the vapour of brome, 1t follows that the two volumes of hydrogen should produce four volumes of hydrobromic acid ; from which it is to be concluded get metallic hydrobromates contain in volume four times. : tuch’ hy drobromic acid as of oxygen in their oxides; , then as 0°08927 ‘gramme of oxygen occupies a volume of 0:0624 lit. 1-270'sramme’of bromuret of potassium ought to yield 0:2496 lit. of Hydrobromie ‘acid: The specific gravity of the vapour. of ‘proniéUeording to these data ought to be 5:1354, and. that of brome acid 26021," T have not yet verified these theoretical Tesiilts' by Experiment. OF DMMUOTO Shi shonr ! ‘bas tslhienie ey: ddydrobromate of Ammonia. A ae _Hydtobromic acid’ gas combines with an equal) volume .of -ammoniacal gas’; the result is a saline compound, which may fn Ailes ‘Obtained’ by combining hydrobromic acid with)liquid ammonia. ‘I havevalready prepared hydrobromate: of ammonia by ‘decomposing ammoniacal gas, or liquid ammonia -with 414 M. Balard on a peculiar Substance [Dre. brome; the results of this action are extrication’ of) heat without light, the evolution of azote, and the formation of hydrobromate of ammonia; I did not observe in any of these cases that a compound was formed analogous to chloride: of azote. Bt eid e Hydrobromate of ammonia is solid and colourless; when moistened and exposed to the air, it becomes yellowish, and acquires the property of tutning turmeric a ted. Iterys- tallizes in the form of long prisms, upon which smaller ones are placed ata right angle; by heat it is volatilized. =, ,)/ : _ Hydrobromate of Barytes. atic! +: AN ‘T obtained this salt by oar the ethereal solution of brome with hydrate of barytes, or by directly combining barytes with hydrobromic acid. Hydrobromate of barytes fuses When exposed to heat; it is very soluble in water, and also dis olves in alcohol ; the crystals are opaque and mammillated, an beat no resemblance to those of muriate of barytes. aye one, i 4 _. | Hydrobromate of Magnesia,: ©) 8 0 This salt is. uncrystallizeable, deliquescent, and, like the muriate of magnesia, is decomposed at a high temperature. bce srtagd te wicite ne Menomunet of Leeds; 41:0 ii Fa dses Wheit an ‘aqueous solution of an hydrobromate is dropped into a solution of lead, a white crystalline precipitate is formed resembling ‘chloride of lead in’ appearance; this precipitate, when strongly heated, fuses into a red fluid which exhales v weak ‘white vapours, which concrete by cooling imto a fil yellow matter. | | pith PO ee TS ' Bromuret of lead in a moist state is decomposable by the iitric and sulphuric acid, brome being disengaged in the first case, and brome and hydrobromice acid in the second ; bet sire éohesion which it acquires by fusion prevents nitric acid froi acting upon it; and it can be decomposed only by boiling sulphuric acid. Fis VeCe En 7 : } rh¥ tLe ells: Deutobromuret of Tin. _. Lhave already remarked that tin is dissolved by hydrobromi¢ acid, with the evolution of hydrogen. The by droleeake nee results when dried is converted into a proto-bromuret, which I have only slightly examined, but which I have ascertaimed, to be very different from the compound obtained when brome is made to act directly upon tin, and it is evidently a deutobromuret. _. Tin burns when put in contact with brome, and it is converted into a solid white substance, which has a cryStalline appeat- ance, and is very fusible, and readily volatilized ; it exhales ont traces of white vapour when exposed to the air; it dissolves 7 water without any sensible extrication of heat, and is converted 1896: “contained in Sea Water. = 415 into an acid deutobromate. When put into hot liquid sulphuric acid, thisicompound liquefies, and remains at the Botions of the acid; having the appearance of oily drops, and without suffering any ‘saduitile alteration. Nitric acid, on the contrary, soon occasions a rapid disengagement of brome; ‘the deutobromuret 6f tin, analogous to the fuming liquor of Libavius, it will bé observed, possesses but few of the properties of this latter com- pound. i 453 7 Bromurets of Mercury. . Mercury..combines, with brome in .several proportions; A solution of an alkaline hydrobromate, acting upon protonitrate of mercury, occasions the formation of a white. precipitate, resembling protochloride of mercury, and which appears to be.a protobromuret of the metal. : ‘ey - Brome attacks mercury strongly ; the combination is effected | with the extrication of heat unaccompanied by light. The résult is a white substance, which sublimes when heated, and which is soluble in water, alcohol, and especially in ether, it is precipitas ble red and yellow by the alkalies, and offers many analogies _ with corrosive sublimate, Itis distinguished by the red vapours of brome which it yields, when treated with nitric acid, and still better by the sulphuric acid ; the advantage of using the: latter acid appears to me.to depend upon the possibility of employing a.higher temperature. | ¢3 we evita mony Ae ~Bromuret of Silver. kbp tr _,.Nitrate of silver produces a curdy precipitate of bromuret: of Silver in the solutions of the hydrobromates. This compound.is of @ canary, yellow colour when dried in the dark ; but if exposed while moist to the light, it blackens, but not so quickly as.the chloride. of silver; like.this, substance also it is insoluble if water, and soluble.in ammonia. Nitric acid produces no effect upon it even when boiling, but sulphuric acid disengages vapour of brome when boiling. Nasent hydrogen decomposes it, and there are produced metallic silver and hydrobromic acid, and I employed this method to analyze the bromuret of silver; I introduced a certain quantity of it into a mixture of pure granu- lated zine and dilute sulphuric acid; the silver was reduced, and I weighed the silver after ascertaining that the zinc had been completely dissolved ; the mean of two experiments, which differed but very little from each other, gave us the composition rie 3). SE igre hiatal palace. POE a Foeee vx auiet toes saps thas SLs 1000 ‘Phis gives 94-29 as the atomic weight of brome, which does not 416 M. Balard on apeculiar Substance (Dec. differ much from that deduced from the analysis of the bromuret. of potassium. | Bromuret of Gold. Brome and its aqueous solution are capable of dissolving smal! portions of gold; and a yellow bromuret is obtained, staining animal substances of a yellow colour, and decomposable by heat into brome and metallic gold. Bromuret of Platina, Platina is not acted upon by brome at common temperatures ; but it is dissolved by bromo-nitric acid, and forms ‘a compound of a yellow colour, which is decomposed by heat, and which; like the chloride of platina, produces sparingly soluble yellow precipitates in the solutions of potash and ammonia. On the Action of Brome upon Metallic Oxides. - Brome acts upon metallic oxides under two different circum- stances ; when they are dry and strongly heated, and at usual temperatures with the presence of water. vat i it the vapour of brome be passed vuver potash, soda, barytes, . _ or lime, at a red heat, vivid ignition takes place; oxygen gas is liberated, and the bromurets of potassium, sodium, &c. are found in the tube. I was unable to decompose magnesia and zirconia in the same manner ; the brome circulated round these ignited earths without either liberating oxygen, or combining with them. Sublimed. oxide of zinc underwent no alteration by the action of brome at a high temperature. , | es '» The metallic oxides which brome is capable of decomposing do not pa susceptible of this alteration when they are com- bined with a powerful acid ; so that I attempted in vain to libe- rate oxygen by passing brome over red-hot sulphate of potash. When an acid has but little affinity for the metallic oxide, the case is different; the alkaline carbonates being completely _ decomposable by brome, which evolves gas consisting of two volumes of carbonic acid and one volume of oxygen. ~ | The. phenomena are very different when brome is made to act upon the alkalies or earths, already mentioned : when they are dissolved in or mixed with a boinsidtable proportion of water, no liberation of oxygen gas is observed, the smell and colour of the brome disappear, but a compound is formed from which brome is evolved by weak acids, such as the acetic acid, and which possesses the property of quickly decolorizing tincture of tournsole. According to these experiments, brome appears to be nF ee of forming bromurets of oxides, analogous to the chlo- rides of lime, soda, &c. , When brome is mixed with a very concentrated solution of potash, the solution after evaporation yields not only cubic 1826.] a contained in Sea Water. 417 crystals af a obromate of potash, but acicular crystals, which. appear to be bromate of potash. Barytes and lime act in a similar manner, but magnesia does not appear to possess the same a pe Analogy leads to the conclusion that these two 8ort8 SP Malt ate cotmected with’ the decomposition of water. The*decompdsition' of water which is so readily effected with the assistifidé’of the alkalies also occurs, but in a less ee di manner when brome acts upon it, with the assistance of the sun’s rays. An aqueous solution of brome which I had fora long time exposed to the rays of the sun, gave sensible indica- _ tions OF ‘the’ presence of bromic and hydrobromic acids, the’ format tar bt can scarcely be explained but by supposing ea se Ds that wat as been decomposed. yp . "Tt appeats to me frdm the facts stated in the last and preced- ing paragraphs, that brome acts less strongly upon the metals than chlorine;does,, but. with more energy than iodine; the evolpien of light and heat which accompanies combination. of the former with these bodies, shows that brome has more resem- blance to the action of iodine under similar circumstances. Although tin, combines with brome with rin Geshengement of light, which it does not with chlorine, it is, perhaps, dependant. . Pe sheneitencs of the brome being fluid, which allows of URAB the combination of greater masses... fi i eet are decomposed by brome, and the bromurets by chlo} i ,,lodine, which decomposes potash and soda very. readily at a.high temperature, does not so act upon, barytes, but. combines with it to form an iodide of an oxide; brome, on the contrary, effects. the decomposition of this base, and also o lime, .but, it does not act so efficaciously upon magnesia, while chlorine, exerts its decomposing action upon this oxide, : lantog Of the Bromic Acid and its Combinations. When brome is shaken with a sufficiently strong solution of potas ter are formed, as I have already mentioned, two very ifferent Compounds ;, the 2 abit of potash is obtained in solution,.and.a white crystalline precipitate settles at the bottom of the syesseln which appears to be bromate of potash, for it fuse uring coals like nitre, and is converted into bromu- ret..oL ; . ! Bape, f potash is very slightly soluble in alcohol; it dis-" solves in,considerable. quantity in boiling water, from which it separates by cooling, in the form of needles grouped together. When. itis, made.to.crystallize by evaporation, it is deposited in lamine of, pe eek ; It is decomposed by heat, deflagrates upon red-hot coals, and when mixed with sulphur, it detonates , bY. PEEGHISION-.siecrmoones yiae A, Gia Dov dnadVe . Rae sclntion.0F bromate. of potash forms a precipitate injope,, of nitrate of silver; this precipitate is white and pulverulent, — _ New Series, vol. x11. - 2E . potassium by, heat, giving out oxygen gas. - 48 M. Balard on a peculiar Substance [Drc. scarcely becoming black by exposure to light, and is thus distin- guished from bromuret of silver, which is yellow, curdy, and readily altered by the solar rays. Bromate of potash does not precipitate the salts of lead, whereas the Bye vprotuets of potash occasions a very abundant crystalline precipitate in them; with protonitrate of mercury the bromate of potash forms a yellowish white precipitate which is soluble in nitric acid. Bromate of otash possesses a property of which the chlorates are destitute, but which exists to a great extent in the iodates; its acid is decomposed by the influence of py depacnn Re causes, as if it were uncombined ; thus sulphurous acid, sulphuretted hydrogen, hydrobromic acid and muriatic acid, react upon the bromate of otash, and produce in the three first cases a disengagement of tase, and in the last instance a compound of brome and — chlorine. goa | . I ttied, but in vain, to obtain an oxide of brome by the decom- position of bromate of potash ; it is true indeed that the failure may be owing to the small quantity of the substances upon which I am able to make my researches. ea la Hydrobromic acid, when diluted with water, evolves brome by agitation with bromate of potash. Diluted sulphuric acid pro- duces at 212° Fahr. a disengagement of gas, which I attempted to collect over water, mercury, and oil. I always procured brome and oxygen gas, which seems to show, either that brome cannot form oxides, or that the compounds, if they could be procured, are less permanent than the oxides of chlorine. _ romate of potash may be obtained by a different process from that which I have described. It is sufficient to combine brome and chlorine, and to mix potash with the aqueous solution of the compound, and instantly there is produced the decompo- sition of water, a bromate and muriate of potash ;. these salts, on account of their different solubility, are easily separated. I employed this process for the preparation of bromate of barytes, which I obtained in the form of acicular crystals, soluble in boiling water, slightly soluble in cold water, and burning with a green flame upon red-hot charcoal. ie When dilute sulphuric acid is poured into an aqueous solution. of bromate of barytes so as to precipitate all the base, the remaining solution is one of bromic acid, from which the greater part-of the water may be separated by slow evaporation; it then. . acquires the consistence of a syrup: if the heat be raised so as completely to expel the water, a portion of the acid is vaporized, and another portion is decomposed into oxygen and brome ; similar effects appear to be produced by evaporating the fluid in vacuo with sul pint acid; water, therefore, appears to be requi- site to the constitution of bromic acid. | Bromic acid reddens tournsol paper strongly, and soon after decolorizes it; it has scarcely any smell, its taste is very acid, \ 1826.} “contained in'Sea Water. 419 but not-at all caustic... Nitric and sulphuric acids have no che- mical action upon it ; the latter indeed, when it is much concen- trated, liberates brome, and produces an effervescence, which is probably occasioned by the disengagement of oxygen. These effects, however, seem to be attributable to: the high tempera- ture which, sulphuric acid produces by combining with the water _ of the bromic acid, for they are not produced by dilute sulphuric acid. . ) The hydracids, and those acids which are not saturated with oxygen, act with great energy upon bromic acid ; the sulphurous and hydrobromic acids and sulphuretted hydrogen decompose it, and so also do the muriatic and hydriodic acids, In the latter case, compounds. of brome with chlorine and iodine are obtained, and these acids, when combined with bases, act simi- larly upon bromic acid., eee f shetiaic acid occasions a white pulverulent precipitate in the salts of silver, which appears to be a metallic bromate. It also precipitates the concentrated solutions of the salts of lead, but the compound obtained is dissolved by the addition of a small quantity of water, and it is distinguished by this solubility from that which the hydrobromates form in the solutions of the same metallic salts; it also gives a white precipitate, as the bromate of potash does, with protonitrate ofmercury. . The properties of bromic acid strongly resemble the analogous compounds of chlorine and iodine; but the impossibility of depriving it of water perfectly, and of boiling it without partial decomposition, most resembles chloric acid, and shows that the onygen is less strongly retained than in the iodic acid. » : The proportions of the principles which constitute. bromic acid show that it is subject to the same laws of composition as _ the chloric, iodic, and nitric acids ; 1°128 of bromate of potash is reduced by calcination to 0°790 of bromuret of potassium. The loss of weight derived from the disengagement of oxygen was consequently 0°338 ; 0°790 of bromuret of potassium contain, according to the analysis already stated, 0°27255 of potassium and 0*51745 of brome; this quantity of potassium requires 0:05563 of oxygen to convert it into potash, which, subtracted from 0°338, leave 0°28237 as the oxygen combined with 0°51745 of brome: bromic acid, according to this experiment, will con- sist of ' 7 BOM G SF aE wk OV OPI aE UM 64:69 Oxygen Lass Pe PRU bed 146 35°31 100-00 In representing the atom of brome by 93°28, derived from the - _ analysis of bromuret of potassium, and supposing the bromic acid to consist of five atoms of oxygen and one atom of brome, 100 parts of bromic acid should ae of | 2ER 420: M. Balard on a peculiar Substance [Dzc. _ Brome oa oooh ldrele nmin oebie’s os ae OUD OXYGEN.» oe:siere view sires wide oad eve ot90 100-00 These numbers differ so little from those deduced from direct analysis, thet the supposition from which they are derived may, it appears to me, be regarded as true. On the Combination of Brome with Chlorine and Iodine. Brome combines with chlorine at common temperatures’; this» combination may be effected by passing « current of chlorine: through brome, and condensing the disengaged vapours by means of a freezing mixture. Chloride of brome is a reddish ellow coloured fluid, much less intense than the brome itself ; it has a penetrating smell, and it causes the eyes to water; its! taste is extremely disagreeable; it is very fluid and volatile. its vapour is of a deep yellow colour, similar to the oxides of chlorine, but not at all resembling the orange vapour of: the brome itself; it causes the metals to burn, and probably forms: with them metallic chlorides and bromurets; chloride of brome: is soluble in water ; the solution resembles it in smell and colour, and, like it, rapidly decolorizes tournsol paper, without redden- ing it: consequently it dissolves in water without undergoing any alteration of properties ; but Py the influence of the alkalies, it decomposes water. Potash, soda, and barytes, poured into a solution of chloride of brome, produce muriates and bromates of these bases, a property Which exists in chloride of iodine, and. which proves that chlorine possesses greater affinity for hydro~ gen than brome does. | ¥ Bromuret of Iodine. Iodine appears to be capable of forming two. compounds with brome ; if these bodies be made. to act upon each other in’ cer- tain proportions, a solid compound is obtained, which, when.’ heated, yields a reddish brown vapour, condensible into small crystals of the same colour resembling fern leaves in form., An additional quantity of brome converts these crystals into a fluid, resembling in appearance hydriodic acid containing much iodine ; this compound is soluble in water, to which it imparts the power of decolorizing tournsole paper without reddening it ; when the alkalies are. poured into it, they form hydrobromates and iodates, as may be supposed from analogy. Bromuret of Phosphorus. Phosphorus and brome put in contact ina flask containing carbonic acid act suddenly upon each other, with the evolution of heat and light ; the result of the combination separates into two portions ; one of them is solid, sublimes-and crystallizes in -1826.] contained in Sea Water. 421 the upper part of the flask; the other is fluid, and remains in the lower part; this appears to contain less brome than the crystalline compound ; in fact it may be made to crystallize by adding a sufficient quantity of brome toit. The fluid compound I shall call the protobromuret of phosphorus, and the solid -deutobromuret. The protobromuret of phosphorus is fluid even at 12° centig. It reddens tournsol paper faintly ; it probably even owes this property to the imperfect dryness of the materials from which I prepared it. It vaporizes readily, and by exposure to the air emits penetrating vapours; like the protochloride it is suscepti- ble of dissolving an excess of phosphorus, and then acquires the property of inflaming combustible bodies, when put into contact with it: it acts very energetically upon water with the extri- cation of much heat, and produces hydrobromic acid, which may be collected in the state of gas, when a few drops only of water are added to it; but it is dissolved if a large quantity of water be used: this acid solution, when evaporated, leaves a residuum which burns slightly when it is dried, and is converted into phosphoric acid. . The deutobromuret of phosphorus is solid, of a yellow colour; when moderately heated, it is first rendered fluid, the colour of which is red, and by increasing the heat, it is converted into vapour of the same colour. ; , hen the deutobromuret of phosphorus is cooled after fusion, or when its vapour is condensed, it yields rhombic crystals in — the first case, and in the second, the crystals are needle-formed, and placed upon each other; the metals decompose it, and there are probably produced metallic bromurets and phosphurets; when exposed to the air, it emits dense penetrating vapours; it _ decomposes water with the extrication of heat, and produces hydrobromic and phosphoric acids. When chlorine is made to act upon either of the bromurets of phosphorus, red vapours of brome are disengaged, and ‘chloride of phosphorus is obtained. Iodine does not decompose these compounds; on the contrary, when brome is made to act upon iodide of phosphorus, violet vapours and a bromuret are pro- duced. ONY) ; ee Bromuret of Sulphur. This compound may be obtained by pouring brome upon sublimed sulphur ; it is converted into a fluid of an oily appear- ance and a reddish tint, which is much deeper than that of chloride of sulphur, and which, like that compound, is capable of emitting white vapours when exposed to the air, and of a. ‘somewhat similarsmell. — - | | : Bromuret of sulphur reddens tournsol paper faintly, but with water it reddens it strongly. Cold water acts slowly. upon bro- 422 M. Balard on a peculiar Substance [Dre, muret of sulphur, but at a boiling heat it produces slight deto- nation, and there are formed hydrobromic and sulphuric acids and sulphuretted hydrogen; whereas chloride of sulphur, under similar circumstances, would have yielded muriatic, sulphurous and sulphuric acids, without detonation. stadia: | iisehiantl Bromuret of sulphur is decomposed by chlorine with. the evolution of brome and the production of chloride of sulphur, Hydrocarburet of Brome. I have observed no appearance either of decomposition or _combination by exposing carbon to various temperatures in contact with brome; but I easily united it with bicarburetted hydrogen, Ifa drop of brome be poured into a flask of this gas, it is instantly converted into a substance of an oily appearance, and heavier than water, and colourless; and instead of the pene- trating smell of brome, it has an ethereal smell, which is sweeter than that of the hydrocarburet of chlorine. . ; The hydrocarburet of brome is readily volatized ; it is decom- posed by passing through a red-hot tube. I obtained in this experiment a deposit of carbon, and hydrobromic acid gas. It burns when presented to an inflamed body, and produces very acid vapours, and a thick smoke formed by very finely-divided carbon, I tried in vain to obtain bromuret of carbon, by expos- ing a mixture of thishydrocarburet of brome to the sun’s rays, , A compound, similar to that now described, may be obtained by distilling the mother-water of the salt works rendered yellow hy chlorine. The brome obtained in this mode is often mixed | with hydrocarburet of brome, from which it is separated by water. It sometimes~even happens, that in performing, this operation, all the brome is converted into this triple compound. This effect is probably produced by the action, of the brome upon a small quantity of organie matter which the salt-water contains, and which imparts to the residuum of evaporation the property of blackening when strongly heated, | Action of Brome upon some Organic Bodies, The great aflinity which brome possesses for hydrogen indi- cates beforehand its mode of action upon’ organic bodies. It decomposes the greater number of them, always forming hydrobromic acid, and sometimes separating carbon. | _ - Brome readily dissolyes in acetic acid, upon which it acts slowly ; it is very soluble in ether and alcohol, The coloured solutions which are formed lose their tint after some days, and hydrobromic acid is found in the liquor, The fat oils produce effects of this nature yery slowly, but they occur instantaneous] when brome is put into essential oils ; when a few drops of this substance are mixed with oi) of turpentine or aniseed, heat is extricated, attended with the production of the vapour of hydro- 1826.) _. contained in Sea Waters. | 423 bromic acid, and the essential oil is changed into a resinous ‘substance of a yellow colour resembling turpentine. Resin acts in the same way with brome; camphor dissolves perfectly well in this fluid, losing almost entirely its smell and volatility b the combination. ‘The compound of brome and camphor soli- difies and crystallizes by exposure to cold. __ The most permanent colouring substances are entirely changed by the action of brome, which takes away their tint, and, like chlorine, converts into a peculiar yellow substance. _ I did not perceive any remarkable action between brome and spat) starch, morphia, margaric acid, &c. : Lhe small quantity of brome which I could spare prevented me from examining how it would act with other organic bodies. ; Natural History of Brome. 1 Brome occurs in very small quantity in sea water; even the mother-water of the salt works contains but very little, although itis much diminished in volume by the evaporation which occa- . glons the separation of common salt, and which does not contain a sensible quantity of it, The nature of the methods by which brome is separated seems to indicate that it exists in the state of hydrobromic acid, and some circumstances induce me _ to suppose that this acid is combined with magnesia; for if the residuum obtained by evaporating the water of salt works be Strongly calcined, it loses the property of disengaging brome by mixture with chlorine; recollecting that the hydrobromates which I have examined are not decomposable by heat except- ing that of magnesia; it leads to the supposition that the water of the salt springs contains this Se Ath _. Marine plants and animals also contain brome. The ashes of the plants which grow in the Mediterranean all give a yellow tint when the soluble part is treated with chlorine. I have also seen the same colour produced by causing chlorine to act upon the solution of the ashes of the Lanthina violacea, a testaceous mollusca,; for which 1 am indebted to M. Auguste Berard, and which this distinguished: officer brought from St. Helena in his second voyage round the world. I have obtained a considerable quantity of brome from the mother-water of barilla employed for the preparation of iodine. = ‘To conclude, it appeared that the residuum obtained by evapo- rating a mineral water from the eastern Pyrenees, which was Strongly saline, became yellow by mixture with chlorine. If brome really exists in a water of this kind, we may expect to Meet with it in salt springs, properly so called, and especially in the mother-water of rock salt; I had not the means requisite for ascertaining this point. What has been stated renders it extremely probable that brome will be found in a great number of marine productions, or of submarine origin. : " 424 M. Balard on a peculiar Substance (Dec. If I have not been deceived as to facts which I have related, they fully authorise, as it seems to me, the opinion which I have stated as to the nature of brome, and which has served me in explaining its combinations. Any substance which, in its separate state, so effectually resists, as brome does, all attempts to decompose it ; which is expelled by chlorine from all compounds of which it forms a part, and always appearing with its original qualities; which, acting upon the combinations of iodine, always replaces that substance, to produce corresponding effects in the new com- pounds; which, notwithstanding this opposition of chemical action, is associated with chlorine and iodine by well supported | analogies, seems, on these accounts, to possess the same claim to be considered as a simple body. If this opinion should acquire confirmation by the subse- | quent examinations to which chemists may subject brome, the rank which it ought to occupy among simple bodies is between chlorine and iodine; it will not be uninteresting to see two substances so nearly allied as chlorine and iodine, admitting a new body between them, and serving, by more intimate relations, to connect a group of agents, the first two of which are already so remarkable. Such an approximation of properties and che- mical relations between these thrée simple bodies will acquire additional importance on account of their common origin. Whilst at the commencement of my researches, in examining the several combinations of brome, I almost always found in them the strongest points of resemblance with the analogous - compounds of chlorine; I confess I felt some scruples in admit- ting brome to be a peculiar substance ; but these scruples have not been able to withstand the power with which chlorine sepa- rates it from its compounds, while brome separates iodine from its combinations. — | I shall not conceal how much the materials which I have been able to collect in order to trace the history of brome have left still to be desired. I should indeed very willingly have deferred their publication until more numerous researches had allowed of my leaving fewer blanks, if I had not thought it, would be more useful in this important object of research to direct the attention of those chemists to it, who possess more power clearly to elucidate the subjects of which they treat. I do not for my own part intend to discontinue my attention to this substance, as soon as the waters of our salt springs are sufficiently concentrated to admit of my conveniently separating the brome from them, especially if this sketch should be so for- tunate as to interest the Academy ; and if fresh efforts should yield me results of sufficient importance, I shall hasten to sub- mit them to it, and shall do it with the most perfect confi- dence, A Wat 1826.] contained in Sea Water. 7 425 M. Gay-Lussac’s Report upon the Memoir of M. Balard respect- ing a new Substance; extracted from the Process-verbal of Monday, Aug. 14, 1826. _ MM. Vauquelin, Thenard, and myself, have been commis- sioned by the Academy to report our opinion respecting a memoir of M. Balard’s, the object of which is to describe the properties of a new substance which he has found in sea water; and we have performed this commission. | M. Balard has given this substance the name of muride; but this denomination being liable to several objections, we have, — with the consent of the author, called it Brome, from Bewpos, a bad smell. Brome is fluid at the average temperature of the atmosphere, and even at 18° below 0° centig. In quantity its colour ts of a deep reddish-brown; in small quantity it is of a hyacinthine red ; the colour of its vapour exactly similar to that of nitrous acid ; it is very volatile, and is converted into vapour at'47° centig. Its smell is very strong, and much resembles that of chlorine ; its density is about 3. | Bs Brome destroys coloursin the same manner as chlorine ; it is soluble in water, alcohol, and ether. M. Balard has combined it with a great number of simple substances, and obtained very _remarkable compounds. Chlorine is more powerful than brome, but in its turn it is stronger thaniodine.. This property renders it very probable that brome is only a comp one of chlorine and iodine, as may be suspected from the affinity which it has for these two bodies. To form an exact idea of the properties of brome, it must be composed with chlorine; with hydrogen it | forms an hydracid, hydrobromic acid, and with oxygen, bromic acid, the compounds of which, with basis, have the strongest analogy with the chlorates. When heated, it decomposes like _ chlorine all the soluble alkaline oxides, and evolves oxygen; when cold, it combines with these oxides, and forms bromurets, which are readily decomposable by heat and the weak acids. It combines also with bicarburetted hydrogen gas, and produces an oleaginous fluid of a very sweet ethereal smell. _ The weight of its atom is 9°328, that of oxygen being unity. M. Balard, when sending his memoir to the Academy, accom- panied it with some small portions of brome, and of some of its combinations, with which we have made some experiments. We have also obtained brome by the process described by M. Balard, by treating the mother-waters of the salt marshes of the plain of Aven, which was sent to us by our colleague M. d’Arcet. : If the few experiments which we have been able to perferm has not afforded us that certainty of the existence of brome asa ~ very simple body, which, in the present day, is properly required, we consider it at least very probable that it isso, The memoir 426 Rev. Mr. Emmett on Combustion. 2 [Dxe. of M. Balard is extremely well drawn up, and the. numerous results which he relates would not fail to excite great interest, even if it should be proved that brome is not a simple body. | The discovery of brome is a very important acquisition to chemistry, and gives M. Balard honourable rank in the career ‘of the sciences. We are of opinion that this young-chemist. is . every way worthy of the encouragement of the Academy ; and we have the honour to propose that his memoir should be printed in the Recueil des Savans Etrangers. Signed VauQquELIN, THENARD, Gay-Lussac, Reporter. The Academy adopts the conclusions of this Report. ARTICLE V. On Combustion. By the Rev. J. B. Emmett. (To the Editors of the Annals of Philosophy.) . ! GENTLEMEN, Great Ouseburn; Nov. 15, 1826. Tue fact has long been established, that when condensation takes place during chemical combination, heat is evolved ;* sometimes the quantity is so small as to be barely sensible; at. others, intense heat is excited, accompanied with emission of light. The old chemists, supposing atmospheric air to be an elementary substance, and finding its presence essential to what is ordinarily termed combustion, gave the name of inflammable bodies to those substances which emit both light and heat when exposed to the air at an elevated temperature; and although cases where both light and heat are abundantly united during combination, where air is excluded, and is indeed unes- sential, are very numerous, yet they limited the signification of the term combustion to those cases which can take place only by the agency of air, which, in the language of modern che- mistry, was supposed to be the only “ supporter of combustion.” When the science of chemistry was reformed by the French philosophers, since the atmosphere was then known to be a mixturet of two gaseous bodies, of which, that which consti- * If any volume of water be mixed with an equal one of the sulphuric acid of com- meree, a great degree of heat is excited; when the mixture becomes cool, it will not occupy the measure of two. yolumes. Nitric acid excites less heat, and the union is attended with less considerable condensation. When water and alcohol are mixed, both effects are witnessed in a smaller degree. The law extends to all classes of bodies. + This limitation is strictly proper in the ordinary affairs of life ; for inasmuch as both life and fire are supported solely by the atmosphere, it is the sensible and obvious supporter of combustion, ~ , { A mixture, because by mixing the proper proportions of oxygen and azote, a com- poms resembling atmospheric air is produced (except that the small proportion of car- onic acid gas, aqueous yapour, and minute quantities of some other gaseous bodies, are wanting), yet neither expansion, compression, heat, cold, ox apy other symptom of ‘ 1826.) Rev, Mr. Emmett on Combustion. 497 tutes about four-fifths is almost inert, serving only to moderate the energy of the other, which consists of one-fifth part; they ascribed to this one-fifth part, which they denominated oxygen, all the properties formerly attributed to the whole atmosphere, which it possesses in a high degree. They followed up the old plan, limiting the cases of combustion to those which cannot take place without the presence of oxygen, which now began to be considered as the only “supporter.” On examining the products of combustion, Lavoisier was the first to determine with rigid accuracy, that oxygen becomes united to the inflam- mable body, that the sum of the weights of the oxygen which disappears, and of the combustible consumed, is precisely equal- to the weight of the product. Hence he inferred that at a cer-~ tain temperature, any one of the class of inflammables attracts the particles of oxygen so powerfully as to separate it from the caloric with which in its gaseous state it is combined: hence this caloric is liberated. Hence he supposed all the light and heat that are evolved to be separated from the oxygen gas.* The old doctrine which recognized in oxygen the only supporter of combustion, continued to prevail, until chlorine, iodine, and perhaps fluorine, were added to the list. Now all these are termed the “supporters of combustion,” Are the interests of science promoted by making this distinction between supporters - of combustion and inflammables? In the common affairs of life the distinction is useful; for the atmosphere is the only gaseous matter which comes under universal notice, and popularly it is with reference to it that substances are inflammable or unin- | flammable, But extend the distinction to the four “supporters,” and we find that carbon is inflammable, oxygen being the sup- porter; but it is uninflammable, in chlorine and (if I recollect facts distinctly) in iodine. Boron is in the same state: other examples might be quoted; but since they will be well known to your chemical readers, | shall not quote any others, particu- larly since these show that a body is inflammable when Cboce to one supporter, but inert when another is applied. Hence each supporter must have its own class of inflammables. | But I extend the application of the query. Were our atmo- sphere composed of hydrogen gas, then oxygen gas and chlorine ‘chemical action, presents itself : therefore it is merely a mixture. Besides, the proper- ties of oxygen gas are in nowise changed; they are only moderated ; and the azote pro- duces no positive effect, except that of moderating the otherwise too powerful energy of the oxygen. * When it is considered that-all bodies absorb much caloric during. their conversion into the gaseous state, which they evolve again during condensation, it is difficult to see how this most eminent philosopher could have made any other supposition; for the Science was just beginning to be framed; he had no means of ascertaining the quantity _of caloric remaining in the product of combustion. Hence, reasoning in a truly philo- Sophical manner, he concluded that, in the case,of phosphorus and iron especially, the Rest eyolyed is that which is required for the conversion of oxygen into a gaseous state ; and surely he made aright assumption, when the contrary could not be proved. | “ 428 Rev. Mr. Eminett on Combustion. Dire. gas would be inflammables.* Were it vapour of sulphur, then iron, copper, and many other metals, would be inflammables, and sulphur the supporter, while zinc{ and charcoal would be uninflammable. Were aqueous vapour our atmosphere, potas- sium would be, perhaps, almost the only combustible § fetes it appears that the terms (I speak of their philosophical applica- tion only) supporter of combustion, and inflammable substance, are merely relative; that which is a supporter in one case is inflammable in another; and vice versd. But again, in cases of combustion, why is one body a supporter of combustion rather than the other? When light and heat accompany chemical combination, the phenomenon is properly and truly styled combustion : each of the substances contains a definite portion of caloric ; during combination condensation takes place; there- fore, the sum of the content of the interstices between the parti- cles of the bodies combined is diminished, and consequently heat is excited. If this be accompanied with light, why is the term combustion to be confined to those cases which require the presence of oxygen, chlorine, or iodine? Is not the action which takes place between filings of copper, or iron and sulphur, as truly combustion? The action is the same; the phenomena are’ the same. However, if it be desired to place Hider one general head those substances which resemble oxygen in their general properties, this is to make a truly scientific arrangement ; but why limit the term combustion to those cases which require ‘their presence, whilst multitudes of examples, answering every requirement, can be produced, where they need not be present ? here is one class of phenomena which extends through, and exhibits itself in, every part of an extensive scale: whenever bodies enter into chemical union, a change of temperature accompanies the change which takes place in the properties of the substances. Metals become oxides; sulphur, phosphorus, carbon, and some other bodies, become acids; potassium, sodium, &c., alkalies, if oxygen be concerned as the supporter of combustion. In other cases, as the union of carbonic acid gas to hydrate of lime, a neutral salt results ; yet in all cases of this order, condensation takes place, heat is evolved in various degrees. Now since under the influence of oxygen, combustion _ * If.a stream of oxygen be admitted into a vessel of hydrogen gas, and an electric ssperk be passed just above the orifice, a cone of flame will immediately appear, and appearances will be the same as when the stream is hydrogen, and the surrounding medium oxygen. - | + A piece of copper foil inflames spontaneously in vapour of sulphur: if iron or copper filings be mixed with sulphur, on applying a moderate heat, violent ignition instantly takes place. t Zine cannot be made to unite directly with sulphur, § This may, perhaps, be controverted, since charcoal and iron, when ignited, decom- ‘pose water; but in this case, external heat is applied ; nor do I recollect to have seen po experimental proof that aqueous yapour alone.can support the combustion of char- oriron, ~ ; (is 1826.] Rev. Mr. Emmett on Combustion. 429 is that combination which is attended with the evolution of light and heat, may we not properly consider every similar act of combination in the same light? If we do, the scale is unbroken ; heat is excited by every such combination; when it becomes so intense as to be accompanied with light, it is am example of combustion: the light and heat are emitted by both or all the substances jointly ; no ote in particular is the sup- porter. Considering the subject in this light, we have a number of substances placed in regular order, whether galvanic, that of real chemical attraction, that of visible chemical attraction, - which makes no corrections for the effects of cohesion, temper= ature, elasticity, solubility, &c. or any other, and the combusti~ _ bility of substances combined, or the ratio of the quantity of heat excited during their combination, will be reciprocally as their distance from the extremes of the scale. If it could be praved that the light and heat arise and are derived from one ody only, that would properly be termed a supporter ; but since this is not the case, neither is a supporter, neither is an inflam mable (except popular language be used) ; but the union of the two produces both light and heat. If the term combustion be applied to.all cases where a temperature not less than that of ignition is excited, ultimately some force or forces will be deve- loped, whose operation may be seen in every case where conden- sation takes place, and to which it is ‘to be ascribed. If we examine the nature of the phenomenon, the rationality ‘of what I have stated will be more apparent. The Jaw seems to be universal, that condensation or reduction of volume excites heat.* If then the density of a compound exceed the mean density of its component parts, heat must be excited. Let m,n, be the weights of two substances; a and 6 their specific gravi- mb+na ties: the volume of the compound = ——— ; Its spec. grav. (= weight _m+n.ab = ac) ~~ mb +na : + if then its specific gravity exceed mt n-¢? heat is evolved during the process of combination, mb+na because condensation is accompanied by the evolution of heat. If the condensation be such that the temperature of ignition, at least, be produced, it is a case of true combustion. Why then arbitrarily limit it to the cases where the presence of one of the received ‘ supporters ” is requisite? It is surely more scientific to recognize one operation from the production of the most intense cold to the excitation of the most powerful heat, appli- cable to every operation and combination of “ undecompounded * The end of a rod of soft iron may be made red-hot by hammering; if a gas be suddenly compressed, heat is evolved ; stamping heats metals, &c. } + This excellent formula is taken from the Retrospect, and does not materially differ from Newton’s. ) 430 * Rev. Mr. Bminett on Combustion. (Dee. substances,” than to propose limitations, which make a number of laws of action out of one; and then we must consider every case of chemical combination which excites the temperature of ignition, as a case of combustion ; whether the resultant be an oxide, chloride, ioduret, sulphuret, phosphuret, or whatever else it may be. It is also universally allowed that the caloric results from, or is evolved in consequence of the condensation which ~ takes place ;* therefore its origin is not to be traced to either substance singly, but to a diminution of the specific heat which is produced by the condensation ; and hence the specific + heat of the product of combustion is less than the sum of the specifi¢e heats of its component parts. The capacity for heat is generally less than the sum of the capacities; and the difference between the sum of the specific heats before combustion and that of the product, whether oxide, chloride, sulphuret, &c. is a measure of the heat evolved during the combustion ; yet in the present state _ of chemical science, the change which takes place in'the capa- city cannot be made a measure of the intensity of the force, nor of the quantity of heat evolved: for let a be any very small interval of temperature ; at the first interval from the true zero, the temperature will be a, and let the capacity or quantity of heat absorbed in elevating the body to that temperature be c; when the temperature is a + a, or 2 a, let the capacity be ¢’; at tem- perature2a¢+a= 34, let the capacity be c”,f and so forth, to any assumed temperature. Now at any given temperature, n a, the specific heat is the sum of the quantities which have been absorbed, i. e. the sum of all the capacities =c +c’ +c” +e” + &c. + c’*~*; whilst the capacity at that temperature is simply e“—", Tf then we make the temperature the abscissa ofa curve, * Tam aware that the phenomena of gunpowder, of oxymuriate of potash (I use the old-fashioned words, not being able to discover any advantage of potassa over potash, platinum over platina) mixed with sulphur or other inflammables, and of similar come , pounds are apparently irreconcilable-with this statement. But we must remember that the same gas, as it exists in different solid compounds, has net a constant density (as - will appear towards the conclusion of this paper); and the quantity of heat remain will be the greatest where the gas is least condensed, i. e. when united with bodies whi have least attraction for it generally. Now in the manufacture of the oxymuriate, or hyperoxymuriate, or chlorate of potash, little heat. is evolved; hence the gas retains much of its elastic force, or is but slightly condensed; hence it retains much of its native energy. Similarly, nitrateof potash, or of copper, or silver, retains much of the energy of oxygen; but when united to iron or zinc, little remains. Here we’ recog- nise one law of action: when a gas, which is a supporter of combustion, enters into combination with solid matter, and is not highly condensed, it must retain much of its jar enetgy; and hence, much gas, containing but little specific heat, may be evolved, even by the combustion of a mixture of solid matters. Nitre must contain much specific heat; for azote is not inflammable: its union with oxygen requires the - aid of external heat: the union of the gaseous compounds of azote with oxygen evolve little heat; the gas is not highly condensed; therefore the acid in nitre retains much of its energy. ; . 4 + By specific heat I mean the whole quantity of caloric or latent heat which is con~ tained in a body. Imention this, because by many writers, specific heat and capacity for heat are made synonimous, | _ t c, ¢, c’, c'™=+ are supposed to increase or decrease according to some definite law. , \ 1896.) ss Rev. Mr. Emmeit on Combustion. 431° its fluxion will be a; make the area equal to the specific heat ; then the capacity for heat, i. e. fluxion of the abscissa x ordi- nate, will be the fluxion of the area: hence the capacity is the fluxion of the specific heat. When then the ratio of at least three capacities of a body shall be experimentally found, the nature of the curve will be known, since itis fy #. In all cases. the capacities of weights, proportional to the atomic weights, and which may be called atomic capacities, must be registered, as also the specific heats of the same; these will represent the capacities and specific heats of the atoms themselves. Thus, if the specific heats of two atomic weights A, B, be 8, s, the capa- cities will be S ands: during combination, if no change take place, the specific heat of the compound will be S + s; and the, capacity S + s; but ifa change take place in the capacity, the corresponding change in the specific heat cannot be known until fy ¢ is known. If we examine a number of cases, we shall, find that during combustion the capacity is generally diminished. Using Dalton’s table of capacities of equal weights, the atomic capacity (1 atom) of oxygen 88°00 + atomic capacity of hydro- gen (1 atom) 21-4 = 59:4; the capacity of aqueous vapour = 13°95 ; hence the diminution of capacity, measured by the same scale, is 45:45. 1 atomic capacity of charcoal 1:56 + 2 atoms. capacity oxygen 76:00 = 77°56; that of | atom of carbonic acid. == 23-1: hence the diminution is 54:46... The capacity is always diminished when heat is evolved during combination; but the change of capacity is not in the direct ratio of the heat evolved, except the capacity be proportioned to the specific heat, in which case the specific heat may be represented by the logarithmic curve. ; In all cases of combustion in oxygen, or of combination with gastous matter, an equal condensation of the gas does not take place. By the above-mentioned formula, having given the rela- tive weights of the elements of a binary compound, the specific gravity of one of the substances, as well as that of the compound, that of the other may be found; forc being the sp. gr. of the nmea.c compound, 6 = The oxygen being 6, its spe- m+n.ad—M.C cific gravity, as it exists in phosphoric acid, = 5:1; in black oxide of manganese 3°1, red lead 3:2, iron mica 2°28, glass of antimony 2°21, red copper ore 1-47, oxide of arsenic 1-4. From these examples, oxygen seems to be most condensed by those bodies which have the greatest attraction for it, i.e. by those. whose electric. state is most remote from that of oxygen, or ‘which have the least force of gravity ; and these are the bodies which evolve most heat during combustion. If chlorine be the supporter, the inflammables follow a different order ; another with iodine ; and another for sulphur, &c. according to their respect- ~~ 432 Rev, Mr. Emmett on Combustion. [Dzc. ive order in the galvanic series, or in the order of the force of gravity. = _ mi aoe The order of inflammability with regard to oxygen is nearly inversely as the atomic capacity: the capacity of gold is 10-0,” silver 8°8, copper 7:04, lead 4°16, tin 4:06, iron 3°64, zinc 3:4, charcoal 1°56, and oxygen being the supporter, those bodies which have the least atomic capacity have the most powerful attraction for it, and evolve most heat during combustion; whilst oxygen seems to have the greatest atomic capacity of all known bodies.’ | ; Since heat is evolved whenever condensation takes place, and - since when the combination of two or more bodies is attended with condensation, heat is evolved, if we consider every such case as an example of combustion, provided heat and light are both evolved, we recognise only one general law applicable to every case of chemical union, one extreme of which is termed combustion ; i. e. that where their electric states or forces of attraction are most remote from each other ; or rather when they differ most from some one substance, on either side, positive or negative, whose force with each is to be compared according to the electro-chemical law of Sir H. Davy. : Some cases of combustion are accompanied with flame, as in the example of sulphur, phosphorus, potassium in oxygen; others are not, as that of iron wire in oxygen gas; bismuth or antimony powder in chlorine. Here again we may trace the operation of a general law. When any part of the combustible: is volatilized, the combustion of its vapour produces flame; if not, flame is wanting. Ifa large flame be made by burning pitch or resin, a large reddish-white flame is produced; ifa large flame of olefiant gas be examined, the flame is whiter, yet red at the top ; if the common carburetted hydrogen gas be used, the flame is te brilliant ; if pure hydrogen, yet paler, and paler in proportion to the purity of the gases ; so that if the oxyhy- drogen blowpipe be used, the flame is faint and small. Newton (who, as was said of him, could see more clearly through a mist than others through a microscope) said, ‘ Flame is vapour heated red-hot.” Now if we examine the matter fairly, we shall find that he was not far from the truth. If much of the inflam- mable body, if solid, at a high temperature, as carbon, be volati- lized, as in the case of resin or pitch, the flame is brilliant, owing to the combustion of the volatifized particles ; but owing to their excess (for much soot is deposited) the flame is red. In a large flame of olefiant gas, less soot is produced, and the flame is whiter. In the case of common carburetted hydrogen gas, little or no carbon is deposited, and the flame is whiter: below this limit, the flame becomes paler; so that when very pure oxygen and very pure hydrogen gas are used, the flame is very pale; and the purer the gases, the paler the flame. Hence then it 1896.) ~ Rev. Mrs Emmmeti on Combustion. 483 appears, that when a solid which evolves much light during combustion is volatilized; the vapour (if it may be so called) evolves light, most probably in proportion to its quantity. When this is diminished, the quantity of light is reduced, until arriving at a state of purity in oxygen and hydrogen gases, the light and heat approach so nearly to the radiant state (owing to the want of a sufficient quantity of matter in the flame) that very little lisht is evolved. Hence we may infer, that the quan- tity of the light’ depends upon the quantity of solid matter in the flame ; for if there be no solid matter, heat sufficient to melt platina, and to produce most vivid light, may pass through a transparent medium without producing any sensible effect; yet if solid matter be introduced, it will be most vividly ignited. Hence a platina wire may slowly consume a mixture of oxygen and inflammable gas. The combustion is too slow to produce flame, yet it is sufficient to ignite the wire: this is analogous to an experiment of Wedgwood, and also to the ignition of spongy platina by a stream of hydrogen, which seems to be owing to the large surface of action and the great density of the metal. “Although the quantity of light emitted by gases of the same nature be nearly in proportion to the quantity of oxygen con- sumed, the law does not obtain with regard to different inflam- mables ; for hydrogen, which consumes the greatest quantity, evolves the least light: the light is in proportion to the quantity of oxygen consumed, the intensity of the heat, the quantity of unconsumed solid raised in vapour, its power of emitting light during combustion directly, and the quantity which escapes combustion in the flame, together with its power of obstructing light, inversely. Neti From the phenomena of combustion is derived a powerful ‘argument in favour of the materiality of heat or caloric. The smallest spark will set fire to phosphorus, and somé other sub- _ stances: from this combustion other combustibles may be inflamed without limit, If then heat be only a vibratory motion excited among the particles, since the cause is equal to the effect; or since the quantity of motion in the exciting body is equal to the whole elapsed; the quantity of motion in the smallest spark is equal to that in the greatest conflagration. Therefore a body of given magnitude can communicate its own force, quantity of force and velocity, to any assignable quantity of matter, which is absurd. New Series, vol. X11. 2 F 434 . Rev, Mr. Emmett on Gaseous: Bodies. {Dzc. Articie VI. On Gaseous Bodies. By the Rev. J. B. Emmett. (To the Editors of the Annals of Philosophy.) GENTLEMEN, In a former paper I committed a considerable error in deduc- ing the law of force in gases from Newtoni Princip. lib. 1, prop. 90, which I wish now to correct. Instead of taking that view of the subject, it ought to have been investigated by Props 90, lib. 2; for since the pressure upon the whole surface of a sphere is equal to that of a cylinder of equal density with the atmosphere of the sphere at all equal distances, whose base is equal to the surface of the sphere ; and the force upon an hemisphere is equal to that of a similar, cylinder whose base is equal to the area ofa great circle. Hence the elastic force of a gas will be nearly in proportion to its density. Many curious results relating to the properties of gases follow from the proportion ; but since I have not leisure to make an arrangement ready for the next number of the Annals, I shall content myself at present with giving notice of the discovery of the error; .and shall communicate the proposition, and trace some of its consequences, by the earliest possible opportunity. | Articte VII. . | Telescopical Observations on the Moon. By the Rev. J. B. Emmett... | (To the Editors of the Annals of Philosophy.) | GENTLEMEN, In the figure (see next page) your readers will find an outline of certain appearances of the moon’s surface, which I named in my last paper. The figure is not presented as a finished or even accurate drawing ; it merely represents the general appearance of those parts on the N boundary of Palus Mcestis, of Hevelius, Mare Crisium of Cassini, which have the appearance of rivers. I have not measured the parts with the micrometer, because I wish to trace the lines to their full extent; to obtain a more _ correct outline of the very numerous similar objects on the S part than I now possess. To free them from illusions, arising from the shadows of ridges and other objects of similar nature, will require observations continued for a considerable 1826.] Telescopical Observations onthe Moon. — 435. time before.the micrometer need be used. The figure here given y te: o § ia pe See Sor 8S 98 iv S S } S j 4A GF x =——T SS SSS =—E-es —————— er = 4A § _nesus. UU ail Ss. : is the result of a considerable number of observations... -I first obtained a view of the most prominent parts, with my. short . aerial, using a power of about 60. A similar view to what I. then obtained is given in Hevelius’s Map, entitled, ‘Tabula Selenographica Phasium Generalis,” (Selenographia, p. 202). The different views obtained at various ages of the moon are to be found in Maps Nos. 8 to 20, in some of which, parts of the broad line which runs almost parallel to the margin of Mceotis are most conspicuous; in others, some of the lines which con-. nect it with Mceotis are seen. In Cassini’s Map, given in Smith’s Optics (the only representation given by that astronomer which I possess), similar portions are to be seen. On applying my reflector with powers of 130 to 400, the Sperm. is asin the figure. A scientific friend of mine lately. observed a part of what is here delineated with an excellent five foot achromatic ; but having less power and light than my reflector, he did not see the finer lines; and from occasional oe I have had, I have not been able to trace them to their ull extent, although, on one occasion, I used a power of 800,,. which is very distinct, and has abundance of light. To see the appearances, the air should be in such a state that good and steady discs of the stars may be obtained; the telescope must have abundance of light, a high power, and be very steadily: mounted. Under these circumstances, it frequently happens, 2F2 : 436 | Mr: Faraday onthe ED Re: that thé wholé cannot be distinetly travéd at oe view: The best age of the moon I have found to be between eight and twelve days after conjunction. | About the § parts are similar appearances, but more compli- cated, for “hich reason I have not yet obtained a complete outline ; they run through Sarmatia to the W of Mare Caspium and towards Paludes, to which they seem to be joined ; forming in their course several spaces, which have the appearance of small lakes. There are similar appearances between § Extremus, Ponti Euxini, and Mare Caspium. | ARTICLE VII. On the Enistence of a Limit to Vaporization. By M. Faraday, FRS. Corresponding Member of the Royal Academy of Sciences at Paris, &c.* Ir is well known that within the limits recognised by experi- ment, the constitution of Vapourf in contact with the body from which it rises, is such, that its tension increases with increased temperature, and diminishes with diminished temperature; and, though in the latter case we can, with many substances, so far attenuate the vapour as soon to make its presence inappreciable to out tests, yet an opinion is very prevalent, and f ‘believe getieral,t that still small portions are produced; the tension being correspondéit to the comparatively low temperature of the substance. Upon this view, it has been supposed that every substance in vacuo, or surrounded by vapour or gas, having no. chemical action upon it, has an atmosphere ofits own around it; aiid that our atmospheré must contain, diffused t 1rough Abel, minute portions of thé vapours of all those substances with. which it is ii contact, even down to the earths and metals. [ pera that a theory of meteorites has been formed upon this. opinion. Pashia the point has never been aishnoHy considered ; and it may therefore not be uninteresting to urge two or three. reasons, in part dependant upon experimental proof, why this. should not be the case. The object, therefore, which I shall hold in view in the following pages, is to show that a /imit exists to the production of vapour of any tension by bodies placed in Ma or in elastic media, beneath which limit they are perfectly xed. * From the Philosophical Transactions for 1826. Ripiaebt hae + By the term vapour, I mean throughout this paper that state ofa body ii which it is permanently and indefinitely elastic, ) Minis. 9 { See Sir H. Desy's paper on Electrical Phenomena exhibited in Vacud. Philos, Trans. 1822, p. 70. - ~ , : 1826.j Existence of a Limit.to Vaporization. 437 .,/ Dr. Wollaston, by a beautiful.train of argument and observa- tion, has gore far to prove that our atmosphere 1s of finite extent, its boundary being dependant upon the opposing powers of elasticity and gravitation,*, On passing upwards from the earth’s surface, the air becomes more and more attenuated, in consequence of the gradually diminishing pressure of the super- incumbent part, and its tension or elasticity is proportionally diminished; when the diminution is such that the elasticity is a force, not more powerful than the attraction of gravity, then a limit to the atmosphere must occur. The particles of the atmo- sphere there tend to separate with a certain force; but this force is not greater than the attraction of gravity, which tends to make them approach the earth and each other; and as expan- sion would necessarily give rise to diminished tension, the force of gravity would then be strongest, and consequently would cause contraction, until the powers were balanced as before. Assuming this state of things as proved, the air at the limit of the atmosphere has a certain degree of elasticity. or tension ; and, although it cannot there exist of smaller tension, yet, if portions of it were removed toa farther distance from the earth, or if the force of gravity over it could im any other way be dimi- nished, then it would expand, and exist of a lower tension; upon the renewal of the gravitating force, either by approximation to the earth’s surface or otherwise, the particles would approach each other, until the elasticity of the whole was again equal to the force of gravity. , ) Inasmuch as gases and yapours undergo no change by mere expansion or attenuation, which can at all disturb the analogy existing between them in their permanent state under ordinary circumstances, -all the phenomena which have been assumed, as occurring with the air at the limit of our atmosphere may, with equal propriety, be admitted with respect to. vapour in general jn: similar circumstances; for we have no reason for supposing that the particles of one vapour more than another are free from the influence of gravity, although the force may, and without doubt does, vary, with the weight and elasticity of the particles of each particular substance. ‘, It will be evident also that similar effects would be produced by the force of gravity upon air or vapour of the extreme tenuity and feeble tension referred to, whatever be the means taken to bring it into that state ; and it is not necessary to imagine the portion of air operated upon, as taken from the extremity of our atmosphere, for a portion of that at the earth’s surface, if it could be expanded to the same degree by an air pump, would undergo the same changes: when of a certain rarity it would just balance the attraction. of grayitation, and fill the receiver . ¥. Phil, Trans. 1822, pi 89... 438 ! “Mr. Faraday on the (Dec. with vapour; but then, if half were taken out ofthe receiver, the remaining portion, in place of filling the vessel, would submit to the foree of gravity, would contract into the lower half of the receiver, until, by the approximation of their particles, the vapour there vraag, Hats have an elasticity equal to the force of gravity to which it was subject. This is a necessary consequence of Dr. Wollaston’s argument. | There is yet another method of diminishing the elasticity of vapour, namely, by diminution of temperature. With respect to the most elastic substances, as air, and many gases, the compa- ratively small range which we can command anes common temperatures: does nothing more at the earth’s' surface than diminish in a slight degree their elasticity, though two or thrée of them, as sulphurous acid and chlorine, have been in part con- densed into liquids. But with respect to innumerable: bodies, their tendency to form vapour is so small, that at common tem- peratures the vapour produced approximates in rarity to the air upon the limits of our atmosphere; and with these, the power “we possess of lessening tension by diminution of temperature may be quite sufficient to render it a smaller force than its opponent gravity ; in which case it will be easy to comprehend that the vapour would give way to the latter, and be entirely condensed. The metal, silver, for instance, when violently heated, as on charcoal urged by a jet of oxygen, or by the oxy- hydrogen, or oxy-alcohol flame, is converted into vapour; lower the temperature, and before the metal falls beneath a white heat, the tension of the vapour is so far diminished, that its existence becomes inappreciable by the most delicate tests. Suppose, however, that portions are formed, and that vapour of a certain tension is produced at that temperature, it must be astonishingly diminished by the time the metal has sunk to a mere red heat; and we can hardly conceive it possible, I think, that the silver should have descended to common ‘temperatures, before its accompanying vapour will, by its gradual diminution in tension, if uninfluenced by other circumstances, have had an elastic force far inferior to the force of gravity; in which case, that moment at which the two forces had become equal, would be the last moment in which vapour could exist around it; the metal at every lower temperature being perfectly fixed. . I have illustrated this case by silver, because, from the high temperature required to make any vapour appreciable, there can be little doubt that the equality ofthe gravitating and elastic forces must take place much above common temperatures, and therefore within the range which we can command. But there is, I think} reason to believe, that the equality in these forces, at or above ordinary temperatures, may take place with bodies far more volatile than silver; with substances indeed which boil under common circumstances at’600°. or: 700° F. » 1826.] | Evistence ofa Limit-to. Vaporization. 439 If; as I have formerly shown,* some clean mercury be put at the bottom of a clean def bottle, a piece of gold leaf attached ‘to the under part of the stopper by which’it is closed, and the whole left for some months at a temperature of from 60° to 80°, the gold leaf will be found whitened by amalgamation, in con- sequence of the vapour which rises from the mercury beneath ; but upon making the experiment in the winter of 1824-5, I was unable to obtain the effect, however near the gold leaf: was brought to the. surface of the mercury ; and I am now inclined to believe, ‘because ‘the elastic force of any vapour which the mercury could have produced at that temperature was less than the force of gravity upon it, and that consequently the mercury was then perfectly fixed. ~ Sir Humphry Davy, in his experiments on the electrical: phe- “nomena ‘exhibited in- vacuo, found, that when the temperature of the vacuum above mercury was lowered to 20° F. no further diminution, even down to — 20° F. was able to effect any change, asto the power of transmitting electricity, or. in the luminous appearances ; and that these phenomena were then nearly of the same intensity as in the vacuum made over tin.} Hence, in conjunction with the preceding reasoning, Iam led to conclude, that they were then produced independent of any vapour of the metals, and that under the circumstances described ; no: vapour of mercury: existed at temperatures beneath 20° F. id Concentrated sulphuric acid boils at about 600° F. but as the ‘ temperature is lowvered, the tension of its vapour is rapidly dimi- nished. . Signor Bellanit placed.a thin plate of zinc at the upper part of a closed bottle, at the bottom of which was some concentrated sulphuric acid. No action had taken place at the end of two years, the zinc then remaining as bright’as at first ; and this fact is very properly adduced in illustration of the fixedness of sulphuric acid at common temperatures. Here I should again presume, that the elastic force which tended to form vapour was surpassed by the force of gravity. Whetherit be admitted or not, that in these experiments the limit of volatilization, according to the principle of the baiance of forces before stated had been obtained, I think, we can hardly doubt that such is the case at common’ temperatures, with respect to the silver, and with all bodies which beara high temperature without: appreciable loss. by volatilization, © as platina, gold, iron, nickel, silica, alumina, charcoal, &c.; and ‘consequently that, at’ common temperatures,- no portion “of vapour rises from these bodies or surrounds them; that they are really and truly fixed; and that none of them can exist in the atmosphere in the state of vapour, : —* Quarterly Journal of Science, x. 354. : athe e, <4 Phil. Trans, 1822;pe Tl. 0 © $°Giornale di‘ Fisicayvy 197, 440 6 Mik Raraday on thes (Duc. But there is another force, independent of that of ptavity,) at least of the general gravity of the earth, which appears to me sufficient to overcome a certain degree of vaporous elasticity, and consequently competent to the condensation. of vapour of inferior tension, even though grayity should be suspended ;, I mean the force of homogeneous.attraction, .§ «) 92 Into a clean glass tube, about half an inch in diameter, intros duce a piece of camphor : contract the tube at the lamp about four inches from the extremity ; then exhaust it, and seal it her- metically at the contracted part ; collect the eamphor to one end of the tube; and then, having placed the tube in a convenient position, cool the other end slightly, as by covering it with a piece of bibulous paper preserved in a moist state by a basin of water and thread of cotton ; in this way, a difference in temper- ature of a few degrees will be occasioned between the ends of the tube, and after some days, or a week or two, crystals of camphor will be deposited in the cooled part; there will not, however, be more than three or four of them, and these will continue to increase in size as long as the experiment is undis- turbed, without the formation of any new crystals, unless the difference of temperature be considerable, | A little consideration will, I think, satisfy us, that, after the first formation of the erystals in the cooled part, they have the ower of diminishing the tension ofthe vapour of camphor, aloe that point at which it could have remained unchanged. in contact with the glass, or in spdce: for the vapour of the cam- phor is of a certain tension in the cooled end of the tube, which it can retain in contact with the glass, and therefore it remaing unchanged; but which it cannot retain in contact with the crystal of camphor, for there it is condensed, and continually adds to its mass, Now this can only be in consequence of a positive power in the crystal of camphor of attracting other jae ticles to it; and the phenomena of the experiment are such as to show, that the force is able to overcome a certain degree of elasticity in the surrounding yapour, There is, therefore, no difficulty in conceiving, that by diminishing the temperature of a body and its atmosphere of vapour, the tension of the latter may be so far decreased, as at last to be inferior to the force with which the solid portion, by the attraction of aggregation, draws the particles to it, in which’ case it would immediately cause the entire condensation of the vapour, The preceding experiment may be made: with iodine, and many other substances; and indeed there is no case of distinct crystallization by sublimation* which does not equally afford evidence of the power of the solid matter. to overcome a positive degree of tension in the vapour from which the erystals-are * Calomel, corrosive sublimate, oxide of antimony, naphthaline, oxalic acid, Sc» fcc ' 1826;] —_. Luistence of a. Limit to. Vaporization. .. 441 formed. The same power, or the force of aggregation, is also illustrated in crystallizing solutions ; where the solution has a tendency to deposit upon _a crystal, when it has not the same tendency to deposit elsewhere. . SHOE LO bi\s059T _ It may be imagined that crystallization would scarcely.go on from, these attenuated vapours, as:it does in the denser states, of the yapours experimented upon... There is, however, no good, reason for. supposing any difference in the force of aggregation. of a solid body, dependant upon changes in the tension of the vapour about it ; andindeed, generally speaking, the method I have assumed for diminishing the tension of the vapour, namely, by diminishing temperature, would cause increase in the force. of aggregation. | Whe i Such are the principal reasons which have induced me to, believe in the. existence of a limit to the tension of vapour. If 1 am correct, then there are at least two causes, each of which is sufficient to overcome and destroy vapour when reduced to a certain tension ;.and.both of Shich are acting effectually with numerous substances upon the surface of the earth, and retain- ing them:in a state of perfect fixity, I have given reasons for supposing that the two bodies named, which boil at, about 600°. F. are perfectly fixed within limits of low temperature which we. can command; and! haye.no doubt, that nearly all the present recognised metals, the earths, carbon, and many of the metallic. oxides, besides the greater number of their compounds, are per- fectly fixed bodies at common temperatures. The smell emitted by yarious metals when-rubbed may be objected to these con- clusions, but the circumstances under which these odours are produced are such as not to leave any serious objections on my mind to. the opinions above advanced. 3 aig é I refrain from extending these views, as might easily be done, to.the atomic theory, being rather desirous that they should first obtain the sanction or correction, of scientific men. I _ should have been glad to have quoted. more experiments upon the subject, and especially relative to such bodies as acquire their fixed point at, or somewhat below, common temperatures, Captain Franklin has kindly undertaken to make certain experi- ments for me in the cold regions to which he has gone, and. probably when he returns from his arduous undertaking, he may have some contributions towards this subject. 4, 442 Aécount of some Volcanic Eruptions, &c. [Dae. ARTICLE IX. © Account of some Volcanic Eruptions, &c. in the Islands of Japan. - Proressor DAuBeEny observes, in his Description of active and extinct volcanos lately reviewed in the Annals,* that “‘ in the islands of Japan, ten'volcanos have been enumerated, but little is known concerning them ;” and he’ only mentions . _ in particular three volcanos in Jesso, the northernmost of the Japanese islands, with two diminutive cones on islands near its south-western extremity, and one volcano in Satzuma Bay in the most southern island called Kiou-siou. In this deficiency of information. respecting so considerable a portion of the volcanic chain extending from the peninsula of Kamtschatka through the Kurule islands and those of Japan to the group of Loo Choo, and thence to Formosa, and the Phillipines, the sub- joined particulars of volcanic eruptions in Niphon, the central and largest island of the Japan group, and also’ in Kiou-siou, extracted from Titsingh’s Illustrations of Japan, may be accept- able to such of our readers as are interested in the subject. They have been derived from some collections relative to the seated of volcanos, made whilst engaged in studying the istory of Meteorites, with the immediate view of preparing the means for investigating the question, whether any important coincidences in point of time could be detected’ between the descents of meteorites and the eruptions of volcanos,+ and with the ulterior design of laying the foundation of ‘a treatise on vol- canic phenomena; this design, however, has been altogether superseded by the publication of Dr, Daubeny’s excellent work, which comprises nearly all the information on volcanos that the present writer had been able to collect. Butin a few instances, as in the present one, the collections alluded to afford particu- lars unnoticed by Dr. D. and these it may now’ be useful occa- sionally to give to the public in this Journal. The following extracts from M. Titsingh’s work + are written in a confused, and in some places in an obscure manner, and exhibit perhaps a degree of oriental hyperbole, or at least of * See the present vol. p. 215. > + Although the idea of the projection of meteorites from volcanos has been discarded by the best-informed writers on their nature and origin, yet there are many facts respecting the meteors from which they descend, and the mineralogical constitution of the substances themselves, which render it necessary in the thorough investigation of their history, to keep in view all the phenomena of volcanos. That meteorites cannot be emitted, as such, from volcanos, appears certain; but that the causes of volcanic phenomena are intimately allied to those of the phenomena of meteorites, if they are not actually the same with them, the present writer hopes to prove, in a work exhibiting the present state of our knowledge regarding meteorites, which will be published in the ensuing spring. . + Illustrations of Japan; by M, Titsingh, translated from the French by Frederic Shoberi, London, 1822, 4to, ; 1826:] 9 an the Islands of Japan.» . 443 exaggeration arising from the fears and sufferings of the nar- rators. They have also, it is probable, undergone some altera- tion in character, from their successive translation from the Japanese language into Dutch, and thence (perhaps through the French)’into English. Although they do not present any novel features in the history of volcanos, they may serve to show that those of Japan are among the most active on the globe; and the swallowing-up of the twenty-seven villages in the province of Sinano would appear to be a parallel case to the phenomenon exhibited by the mountain Papandayang ‘in Java, described by Dr. Horsfield.* : : . It is not easy to decide whether the convulsions recorded of the Mountains Unsen and Miyiyama in the island of Kiou-siou, were really of a volcanic nature or not: if they were, the descent of the water produced, as at Vesuvius, by the condensation of the vapours emitted by the crater, or, as in the Andes, by the melting of the snow upon their summits, caused by the erup- tions, has doubtless been mistaken in the narrative, for the ejection of water from the volcanos ; an error which has more than once been committed by describers of volcanic phenomena in Europe. _W. B. In the beginning of the month of Sept. 1783, M. Titsingh received from Yedo the following particulars of the dreadful ravages occasioned by the eruption of the ‘volcano, Asama-ga- daki, in the districts of Djozou and Zinzou. | ~~ On the 28th of the sixth month of the third year Ten-mio (July 27, 1783), at eight o'clock in the morning, there arose in the province of Sinano,} a very strong east wind, accompanied with a dull noise like that of an earthquake, which increased daily, and foreboded the most disastrous consequences. On the 4th of the seventh month (Aug. 1), there was a ‘tremendous noise, and a shock of an earthquake; the walls of the houses cracked, and seemed ready to tumble; each success- ive shock was more violent, till the flames burst forth, with a terrific uproar from the summit of the mountain, followed by a tremendous ‘eruption of sand and stones: though it was broad day, every thing was enveloped in profound darkness through which the flames alone threw at times a lurid light. Till the 4th of August, the mountain never ceased to cast up sand and dbo his 485 ey | (ON ~The large village of Sakamoto, and several others situated at the foot of-the volcano, ‘were soon reduced to ashes by the ignited’ matter’ which it projected, and by the flames which burst from the earth. The inhabitants fled; but the chasms every-where formed by the opening: of the ground prevented * See Daubeny’s Volcanos, p. 317. ‘gi ‘ + An extensive central province of the island of Nifon, to the northewest of Kai and. -of Mousasi, in which Yedo is gituated, 444 Account of some Volcanic Eruptions, 5c. [Des their escape, and in a moment a great, number of persons. were swallowed up, or consumed by the flames; yiolent shocks con- tinued to be felt till the 8th of the seventh month, and were per- ceptible to the distance of twenty or thirty leagues : enormous stones and clouds of sand were carried by the wind ae the east and north, + hg i ." The water of the rivers Yoko-gawa and Karousawa, boiled ; the course of the Yone-gawa, one of the largest rivers of Japan, was obstructed, and the boiling water inundated the adjacent country, doing incredible mischief, The bears, hyenas, an other beasts of prey, fled from the mountains flocked to the neighbouring yillages, where they devoured the inhabitants, or mangled them in a horrible manner. The number of dead eradually increased in violence. On the Sth, a shower of sand and ashes fell on all sides; and on the 6th, the volcano projector ich were re On the 7th, about one o’clock, several rivers became dry; at two a thick vapour was seen at Asouma over the oe gawa, the black muddy water of which boiled up violently, An immense quantity of red-hot stones Hoating on the surface gave it the appearance of a torrent of fire. Mokou, one of the life- guards, and a great. number of men and. horses, were swept away by the current, and cast on shore at Nakanose, or carried along by the riyer Zin-mei-gawa, | F preg tians | ~ On the 8th, at ten in the morning, a torrent of sulphur, mixed with rocks, large stones and mud, rushing from the mountain, precipitated its jnto the river Asouma-gawa, in the districts, 1896.] "the Wslands of Japan. 44s of Djozou and Gemba-kori, and swelled it so prodigiously that it overflowed, carried away houses, and laid waste the whole country. The number of persons who aA was immense. At Zinya-tchekou, on the road to Naya-kama, there were incessant and violent shocks from the 6th to the 8th. | At Sakamoto-tchekou, there was a continued shower of red- hot stones from the 5th to the 6th. “At Fonsio-tehekou, gravel fellin an incessant torrent. At Kourayé-sawa, there fell such a prodigious quantity of red-hot stones, that all the inhabitants Hetfield in the flames, with the exception of the chief magistrate : the exact number of thé dead is not known. “io ver *- On the 9th, about one o’clock, large trees and timbers of houses began to be seen floating on the river of Yedo, which was soon afterwards completely covered with the mangled car- easses of men aiid beasts. In the country of Zinzou, the devas- tation extended over a tract of thirty leagues. ! | ~ At Siomio, Asouma-kori, and Kamawara-moura, at the foot of Mount Asaina, all the inhabitants perished except seventeen. . Half of the village of Daizen-moura was carried away by the ava. | The villages of Nisikoubo-motra, Nakai-moura, Fao-moura, Kousaki-faramoura, and Matski-moura, totally disappeared. At the village of Tsoubou-moura, the warehouse of Souki- Sayemon was preserved ; all the other houses, with the inhabi- tants, were swept away by the fiery deluge: . 5 ae ~The villages of Tsoutchewara-moura, Yokokabe-moura, Koto- moura, Kawato-moura, Fa-motira, Kawafarayou-moura, and Farada-moura were likewise swept away. : ~ Fifty-seven houses of the village of Misima-moura were swal- ‘lowed up, and sixteen persons carried away by the torrent, he every where left a sediment of sand of the depth of ten eet. | iy At Gounba-kori, Kawasima ‘and Fara-moura, out of 153 houses, six only were left; the others were carried away. The whole village of Obasi-moura disappeared. e village of Ono-moura and the guard-héuse of Mokou were swept away by a torrent of boiling mud. The village of Yemaye-moura was completely buried by sand. _ Many other villages, besidés those here named, either partly disappeared with their inhabitants, or were swept away. It was impossible to determine the number of the dead, and the devas- tation was incalculable. P.97—100. ees _ On the 18th of the first month of the fifth year Kouansez (1793), about five o’clock in the afternoon, the whole summit of the mountain of Unsen fell in, and the cavity thus formed was so deep, that it was impossible to hear the noise made in falling by the stones that’ were thrown into it. Torrents of boiling water gushed from all parts, and the vapour which rose from it 446 Account of some Volcanic Eruptions, &c. [Dzc. neg eivie a thick smoke, _ The latter phenomenon ceased in a ew days. On the 6th of the second month, there was an eruption of the volcano of Bivo-no-koubi, about half a league from its summit. The flames ascended to a great height; the lava which ran down spread with rapidity at the foot of the mountain, and ina few days the whole country, for several miles round, was in flames. The fire consumed all the trees on the neighbouring heights, and the valley, in which it made the greatest havoc, was soon covered with relics of burnt matter, and filled. with stones and ashes. The fire was not like ordinary fire; it was sparkling and of areddish colour, interrupted from time to time by brown blazes. On the Ist of the third month, at ten o’clock at night, a tremendous earthquake was felt throughout the whole island of Kiou-siou,* but particularly in the province of Sima- bara. _ The first shock was so violent that people could scarcely keep on their legs; they.were seized at the same time with a corals stupefaction, so that. they had scarcely presence of mind to provide for their personal safety. Immense rocks were * precipitated from the mountain; the earth opened, the houses were shaken with such force, that the inhabitants durst not stay in them for fear of being crushed in the ruins. Neither could they venture to stop any where, from apprehension of the inun- dation which usually follows a violent earthquake; and the recollection of what had happened some years before in Sinano, | as already related in the proper place, heightened the terror of the inhabitants. Carrying the sick and the children in their arms, they set out in troops in quest of some place of refuge from ‘a similar calamity. Nothing was to be heard but cries, lamentations, and fervent prayers imploring the protection of heaven. The shocks having ceased, in afew hours they returned to their homes. Some houses were demolished, and their inmates buried in the ruins; but fortunately the mischief was not so great as had been feared. The mountain meanwhile continued burning, and the lava spread obliquely towards the castle; but being stopped in its » course by a great number of rocks, it turned slowly to the north. The inhabitants were in terrible alarm, because the shocks were incessantly recurring, though with less violence than at first. On the Ist of the fourth month, about noon, when every body was at dinner, a fresh shock was felt with a motion which lasted upwards of an hour and a half, and became more and more violent, threatening all around with instant destruction. It was not long before several houses beyond the castle were ingulphed with their inhabitants, which seemed to be the signal for the most dreadful disasters. The cries of men and animals aggra- * Kiou-sion, or Kidjo (the nine provinces) is thus named on account of its division into nine provinces. It is the second in extent and the. westernmost of the islands . composing the empire of Japan. | ‘ 1826:] in the Islands.of Japan. 447 vated the horrors of the catastrophe. Prodigious rocks rolling from the mountain overthrew and crushed every thing that hap- pened to be in their way. A tremendous noise, resembling loud and repeated discharges of artillery,, was heard under ground and in the air: at length, when the danger was supposed to be over, a horrible eruption of Mount Miyiyama took. place: the greatest part of it was exploded into the air, fell into the sea, and by its fall raised the water to such a height as to inundate both the town and country. At the same time, an enormous quantity of water issuing from the clefts of the mountain, met the sea-water in the streets, and. produced whirlpools, which, in some places, washed away the very foundations of the houses, so as to leave not a vestige of habitations. The castle alone remained uninjured, because the water could not penetrate its strong massive walls: several houses near it were so completely destroyed, that not one stone was left upon one another. Men and beasts were drowned by the flood. _ Some were found. suspended from trees, others standing upright, others kneeling, and others again on their heads in the mud; and the streets were strewed with dead bodies. Out of all those who fled for the purpose of seeking refuge in the castle, a. very small number effected their escape, and all these had received more or less injury. The cries of those who were. still alive beneath the ruins pierced the heart, and yet no assistance could be rendered them. At length recourse was had to the expedient of sending fifty criminals from the castle to remove the rubbish, for the purpose of extricating such of the miserable wretches as were still living, and of interring the dead. Of those who were taken out of the ruins, some had their legs, others their arms, or other members, fractured. The tubs which are used in Japan, instead of coffins, for burying the dead, were uncovered in the cemeteries, or broken, the large stones laid over them having been carried away by the torrent. Thus the whole country was all at once trans- . formed into a desert; but the province of Figo, opposite to Simabara, is reduced to a still more deplorable state. : Its form seems to have been entirely changed; not the least trace of what it was formerly is now to be discovered. A great number of vessels which lay at anchor in the neighbourhood went to the bottom ; and an incredible number of carcases of men and beasts and other wrecks, were brought down by the current, so that the ships could scarcely force a passage through them. The-wretchedness that every where prevails is inexpressible, and fills the spectator with horror. The number of those who are known to have perished exceeds 53,000; and it is impossible to | describe the consternation produced by this catastrophe. P. 109—112. 448 “Heights of Motintain’ Pee. ARTICLE X. Altitudes of the Stations, and of several other Remarkable Hills - in England and. Wales, in English Feet above the level of the Sea, with Occasional Notices of their constituent Rocks; com- puted from the Observations made in the Course of the Trigo- nometrical Survey.™ | * Feet Agnes Beacon (St.) Cornwall ...4..Clay-slate wisi. 621 Allington Knoll, Kent ......00..566.Weald clay ...:53 829 Allport Heights, Derbyshire .....+++.Millstone erit’ os 980 Alnwick Moor, Northumberlandsicscicccceiscceccceys 808 Aiin’s Hill (St.) Surrey wees ec eeese aioe Marine évvs!' 240 Arbury Hill, Northamptonshire ......Oolité 6.3.0.6. .° 804 Arran Fowddy, Merionethshire ......Greywacke slate. . 2955 Arrenig, Merlonéthshive socvcsasees Creywacke slate... 2809 Ash Beacon, Somerset os iso. see Cea eee ee EE 665 Ashley Heath, Staffordshire eee ee eee eee oe ee ee oe 801 Axedge, Derboshite 2b. 6 P35% SEER EE, PE TAGE POT88 Bagborough, Somerset..............Greywacke slate... 1270 Bagshot Heath, Surrey ossceeeeeess Upper Marie ....° 463 Banstead, Surrey’....ceceesceecvee blastic clay 2.3... 576 Bar Beacon, Staffordshire ..........Newred sandstone, 653 Bardon Hill, Leicestershire ..........Greywacke ..6.5, 853 Barnaby Moor, Yorkshire ever eeeercen eves USS te. ee 784 Beacon Hill, Weesnee 5s Ce ORS PESO Beacons of Brecknock, Brecknock ,. ..Old red sandstotie, 2862 Beachy Head, Susser ........ PERT he See Vea te | Beeston Castle (Top of) Cheshire ......... PES UITERAL Wk oid Belle-field Hill, Cheshire........ ORT PETA FUE a) Beryl Hill, Lancashire ..... Coe ne CEE See Coke OEE REUSE ROO Billing Beacon, Lancashire .......ceeesees ocsceeses OBO indown, Cornwall ........ Wvaeress eee be CS gk: 658 Black Comb, Cumberland ........6. Clay-slate ..:... 1919 Black Down, Dorsetshire ...... i OME ec bareus ta ORT Black Hambleton Down, Yorkshire .,Oolite .......... 1246 Blackheddon, Northumberland ....0 2. .cecessee acy S29 620 Bleasdale Forest, Lancashire ........Millstone grit .... 1709 Bodmin Down, Cornwall ...cc.cccccedeccsccecessce 045 Bolt Head, Dev0senere’. oo cs ccedtceccsatacecs eSeceas | Cou Boulsworth Hill, Lancashire ......'..Millstone grit .... 1689 Botley Hill, Surrey....... aa sks COLS Chalk oo... tes. O80 Botton Head, Yorkshire .......+.+..Oolits ........... 1485 * Oiitlines -of Mineralogy and Geology, comprehending the Elements of those Sciences ; intended principally for the Use of Young Persons, Fourth Edition, 1826. .1826.] | in England and Wales. Feet Bow Brickill, Bucks ......+0+s0e+-Jtronsand ...... 683 ‘Bow Fell, Cumberland ........+.+. ...Clay-slate ...... 2911 Bbw Fs, Susseva winds occ fave CATR ME wii’ 702 Dradfieid: Point,. Yorkshire ..-.icviiiiie es 08 ee Fe weles eisai 1246 ‘Bradley Knoll, SrMMERDNGG. osicraiaacenutnudenbwens 26 973 Brandon Mount, BI UERAIA. a cieci~sie sore ee ge pee Wie abe 875 Brenin Fawr, Pembrokeshire Sisistclag! SARL OME ot sbi BOD Brightling Down, Susser. .....0eesceesscoceeecess 3. 646 Broadway Beacon, Gloucestershire... iQolite’ ..cia08. »» 1086 Brown Clee Hill, Shropshire ..... iets , Trap 5 SA 2 1805 Brown Willy, Cornwall ..s6ceccevee Granite ........ 1368 Bull Barrow, Dorsetshire ...cccceceeees POV ORS 2 Beets 927 - Burian (St.), Cotnwalbids. ccna aedieDs tank. wots 415 Gtirleiah Noor, Yerkeehtre.. .... cusses see's vdeissed on i 6 ale OOD Butser Hill, Hampshire ......e0006- Chak 3.3.7 ves “RA -‘Butterton Hill, Devonshire ........65 Granite ......... 1203 Bwlch Mawr, Caernarvonshire ... . .Greywacke slate.. 1673 Cader Ferwyn, Merionethshire ......Greywacke slate.. 2565 Cader Idris, Merionethshire ........ Green st.and slates 2914 Cadon, Barrow, Cornwall .......... Clay slate 1011 . Caermarthen Vau, Caermarthenshire ........0eeeereees 2596 Calf Hill, Westmoreland ......... PreGame ed os 2188 Capellante, Brecknockshire . » Old ved sandstone, 2394 Capel. Kynon,: Gubbietesishive’ 4 Howl Geen. joo 5) ie 1046 Carn Bonellis, Cornwall..........+.. Granites sii k .28 822 hie Minis; Corsunall . os canad. sale sck SORTA. eig » 805 Carnedd David, Caernarvonshire. ....Greywacke ...... 3427 - Carnedd. Llewellyn, Caernarvonshire . .Greywacke ...... 3469 Carraton Hill, Cornwall .......4.. GORDO TUL pal UG Wa; 1208 Castle Ring, ‘Staffordshire a ae et \Newreddandatone, 715 Cawsand Beacon, Devonshire ...... Grantee eee: 1792 © Cefn Bryn, Glamorganshire. ........ Old red sandstone, 583 Chanctonbury. Hill, Sussex ........0- Challgs ito sf. cs 814 Charton Common, ‘Dorset NG's 14s 8 OPUS. oc bore Cheviot, Northumberland. .......... Greenstone? .... 2658 Clifton Beacon; aR os oat os Mare RIWL cowed. 417 Cleave Down, Gloucestershiré........ Odhtersidaecd el 1134 Collier.Law, Durham ........0.600% Millstone grit .... 1678 Coniston Fell, Lancashire ........4. Greywacke ...... 2577 Cradle Mountain, Brecknockshire ....Old red sandstone, 2545 . Cross Fell, Cumberland .......0000 Coal measures.... 2901 Crowborough Beacon; Susser. ...... Iron sand........ 804 Cern y Brain Mountain, Denbighshire, Mountain limest,? 1857 Danby Beacon, Yorkshire ...seesee Oolit6s seed ibe .. 966 ‘Deadman, Cornwall .... CUE wag rately! oc widie WA 018 sb, metstieg New Series, VOL. XII. 26 . 450 Heights of Mountains [Drc. Feet Dean Hill, Hampshire .....++0+++.++Plastivclay ...... 639 Delamere Forest, Cheshire ...... ...Newredsandstone, 596 Dent Hill, Cumberland ............Greywacke ...... 1116 Ditchling Beacon, Sussex ....0+..+sChalk .......... 858 °— Dover Castle, Kent 1... voce veews iow ORB 4 dues wa! > AED Dum don Hill, Dorset...... oe eeeee ee ee ee er 2 2 7 879 Duhdon Beacon, Somerset . 20... ses Oosivdawsl pee eee” Dunkery Beacon, Somerset.......... Greywacke ...... 1668 Dundry Beacon, Somerset .......... Oolite iowesd. yew dh OO Dunnose, Isle of Wight ...........lron sand........ 792 Dweggan, near Builth, Brecknockshire . Old red sandstone, 2071 Easington Heights, Yorkshire ......LiaS s.sssseseees 681 Epwell Hill, Oxford sseneceseeees Oolite eeoeteeeoves 836 Fairlight Down, Susser. ........2.5.Chalk ...c...005 699 Farley Down (near Bath) Gloucestersh.Oolite .......... 700 Firle Beacon, Susser ....... pdivrel Chath sss. ave ee Folkstone Turnpike, Kent .........sChalk .......... 575 Frant Steeple (Top) Susser..........Jron sand........ 659 Purland (near Dartmouth) Devon ....Greywacke ...... 589 Garteg Mountain, Flintshire ...... » aie’ ‘ viet, i : 835 _ Garth (The) Glamorganshire. ... 2... 03 svevivowed. eel 1981, Gerwyn Goch, Caernarvonshire ......Greywacke ...... 1723 Go Hill, Lancashire...... TEPPTETETT i es Goudhurst, Kent ......... osoo soo on s eeu ebiciigan ier Grassmere Fell, Cumberland ...eucveece cece ~wuode tees QRS Greenwich Observatory, Kent ......Plastic clay...... 214 Gringley on the Hill, Vonlaksie PPE errs rae sel wers. Gwaunysgaer Down, Lintshire ......M. limestone?.... 732 Haldon (Little), Devonshire ........Greensand ...... 818- Hanger Hill (Tower), Middleser v.sscscesceescesevevee 251 Hathersedge, Derbyshire.....<......+Millstone grit .... 1877 Hawkeston Obelisk (Top) Shropshire. ........ ey a eo) Hedgehope, Northumberland ...,....Greenstone? ..,. 2847 Helvellin, Cumberland ..........6 . Clay slate ...... 3055 Hensbarrow Beacon, Cornwall. ......Granite ........ 1034 Heswell Hill, Cheshire.......+..+...New red sandstone, 475 Highbeech, Essex ................sLondon clay ....° 750 Highclere Beacon, Hampshire ......Chalk .......... 900 Highgate Down, Pembrokeshire......Old red sandstone, 294 High Nook, near Dimchurch, Kent oe... sce. eeeeees 28 High Pike, Cumberland .........,..Clayslate........ 2101 Hind Head, Surrey ...........+....Green sand ...%.. 923 Holland Hill, Nottinghamshire .,..,,.Newredsandstone, 487 1826] im England and Wales. = 451 Feet Holme Moss, Derbyshire ...»+++++.»Coal measures,... 1859 Hollingborn Hill, Kent .+++++e0+++sChalk yeye0+,+-. 616 Holy-Head Mountain, Anglesea .......Clay slate?....... 709 Hundred Acres, Surrey ..sesecceeee Plastic clay...... 443 Hunsley Beacon, Yorkshire ....+++++sChalk. ..peecee0» Od] Ingleborough Hill, Yorkshire ..,.,...,Mountain limest. . 2361 - Inkpin Beacon, Hampshire eceeeeree »Chalk ‘ he ee 4 i 1011 Kensworth, Hertfordshire ,..++++++sChalk .ve-.--++5 904 Kilhope Law, Durham _....+++++++»Mountain limest., 2196 King’s Arbour, Middlesex .,..,.,,--London clay’ ..., 132 Kit Hill, Cornwall. .iseecoercscecs Gtanite ¢seseee, 1067 Lansdown, Somersetshire...+ese2e++-Oolite seeseeeree 813 Ledstone Beacon; Norkshire . .seineser tense vawriscrenie 208 Leith Hill, Surrey) ssdsreeeree+ee Greensand ...... 993 Lillyhoe, Hertfordshire .+4+.0+r+2¢+Chalk ...452-+.- 664 Llandinam. Mountain, Montgomerysh. Greywacke ...,., 1898 - Llanelian Mountain, Denbighshire ....Transition limest.. 1110 Llangeinor Mountain, Glamorganshire, Coal measures..,. 1859 Llannon, Caermarthenshire ..,,......Greywacke slate... 912 Liwydiart Mountain, Anglesea .......Clay slate? ...... 5238 Lone Mount Forest, Shropshire .....,Greywacke ...... 1674 - Long Mountain, Montgomeryshire... .Greywacke ....,. 1330 Loosehoe, Yorkshire .. haseeeeeea -Oolite ec eee 4 ¢oee 1404 Lord’s Seat, Yorkshire,..,.++++++-.-Millstone grit.,.. 1715 Maker Heights, Cornwall .,.,.«+...Greywacke? ..+. 402 Malvern, Hills, Worcestershire ...,.,.-Hornblende rock, 1444 Marros. Beacon, Caermarthenshire .,..cseecrsesesecere O14 Margam Down, Glamorganshire . ....Coal measures .... 1099 May Hill, Gloucestershire ..,,..+,..Lransition limest., 965 Moel Famman, Denbighshire, ,.,.+,.-Greywacke .,.,,, 1845 Moel Morwith, Denbighshire .,..,.+.Greywacke ....., 1767 Moel Issa,, Denbighshire .....++++».-Monntain limest. , 1037 Moel Rhyddlad, Anglesea .,..++-+»+»Clay slate? ,..... 4065 Moor Lynch (Windmill) Somerset eee Lias ee ee ee) 30 Motteston Down, Isle of Wight ....,,Chalk ..... ver a ORS Mow Copt, Cheshire, ......004. ... Coal measures.... 1091 Muzzle Hill, Bucks ......... = ig se pip bpp BMURMLE I 8 a1 OE Nettlebed (Windmill) Oxfordshire... puving eed Fin peuodken New Inn Hill, Caermarthenshire..cs.ecceeseseeesseecie 1168 | Newton Down, Pembrokeshire ......Old red sandstone 322 Nine Barrow Down, Dorsetshire,.....Chalk ...s+¢s+2 642 Nine Standards, Meemmckeleed . ov. ++Millstone grit ....,2136 452 Heights of Mountainsin England and Wales. [Dxuc. Feet North Berule, Isle of Man ..........Greywacke .....: , 1804 Norwood; Surrey......55 seeeeeesssLondon clay’ ...,)' 389 Nuffield Common, 1140 aie SOV Ohalen Gg. ds eee Ogmoor- Down, Glanorganshivess «S00 olbdead x’ 299 Paddlesworth, Kent......seeeeeee.sChalk. .....e..05 9 642 Pen Hill, ego ase Say Sp ea SOV OS a Pendle Hill, Lancashire ...«.. Millstone grit .... 1803 Pengarn, Merionethshire vvsuvs sees es Greywacke? ..... 1510 Penmaen Maur, Caernarvonshire .....cceee cece dees . 1540 Pennigant Hill, Yorkshire. ..........Mountain, limest, . 2270 Pertinney, Cornwall CRSA > ww RAA DEVENS COU hee Gee Pillar, Cumberland .. 2... 00+ cieokied:S 2 CS Ob wie banger . 2893 Pilsdon Hill, Dorsetshire... ....+4. ..Green sand? os... 984 Plumstone Down, Pembrokeshire. ....Greenstone ...... °° 573 Plynlimmon, Cardiganshire -...+04. + sGreywacke eeesee 2463 Pontop Pike, Durham ...... ....+-Coal measures,... 1018 Portsdown Hill, Hampshire ........ merge SONS: PAA Precellx aint Pembrokeshire ...sscecsescvesvueeevees VT64 Radnor Forest; Radnorshire ...s... syGreghianiare 4 2% 2163 Rhiw Mountain, Caernarvonshine ....Greywacke? .... 1018 Rippin Tor, DEO Vey 053 ees sGranite!) 3.006. (1649 Rivel Mountain, Caernarvonshire ....Greywacke? .... 1866 Rivington Hill, Lancashire . . .Millstone grit . . 1545 Rodney’s. Pillar (Base of) Hontgom.. Trap PES + bTG 2 EOD Rook’s Hall, Sessessd vv ieiaiels on ae.ee po ueele ri. Susis aoe 902 Roseberry Topping, Yorkshire. -...... Oolite...i5 30. 322022 Rufflaw, Northum erland -... é oie SEU TTURIGT F BELG sy 695 .. Rumbles Moor, Yorkshire ..........Millstone grit .... 1808 Saddleback, Cumberland .........++. Greywacke’ B) dW Q2FBT Sarum (Old), WVSIEG EF nS écsen sence siGhaiko.. et es 309 Sca Fell.(Low Point), Cumberland . ..Clay slate’ ...... 3092 Sca Fell (High Point), Cumberland. ..Clay slate ...... 3166 Scilly Bank, Cumberland ...ccescccvecseseee SEO DUET 2600 Scutchamfly Beacons Berks. i539) ble sa Qs ik Mosel. BES Sennen, Cornwall... occcveseceabee Granite SOV GING 387 Sherwood Forest, Nottinghamshire ....Newred sandstone, | 600 Shooters Hill, Kanha vis 3 vee beeens . Plastic clay ..... 446 Shunnor Fell, Yorkshire .........4+. Millstone grit .... 2329 Simonside Hill, Northumberland ......Coal measures.... 1407 Skiddaw, Cumberland .......+. . Greywacke 1 Qf, see, 3022 ' Saea Vell’ aia Ja.,0et. «60 o ASPERROS Teed vieieeees, 2004 Snowdon, Caernarvonshire....+.0005 . Greywacke Whey. BEAL Staincross Heights, Yorkshire ..ssceceeeucsveveeoese O14 1826.] Analyses of Books. | 453 : Feet Stathern Point, Leicestershire......+-Oolite ..sseeeess 490 Stockbridge Hill, Hants ..... SHAG wees ane ae ere 620 St. Stephen’s Down, Cornwall ......Granite ....2... 605 Stow Hill, Herefordshire.......... be chlor poigeaieas? $417 Stow on the Wold, Gloucestershire. ...cccccsecnecsoens 883 Swingfield Steeple (Top), Kent ... 002+. soho melt hie ahad ie eO Symond’s Hill, Gloucestershire .....+++05 Sb eos te yore EDD Talsarn, Cardiganshire ..... vereeesGreywacke....... 1143 Tenterden Steeple, Kent ......... te PEE SR Si SURE RA 322 Thorney Down, Somerset ....eeeee- Mountain limest.. 610 Tregarron Down, Cardiganshire ...... Greywacke ...... 1747 Trellez Beacon, Monmouthshire......0.ccencseecccees 1011 Trevose Head, Cornwall ...... APE Khe vind ph ivene nbdeiinat Winters @ race... Vorkehtnt i. once yiwies « vtlin W889. « avy er 2186 Weaver Hill, Staffordshire .......... Millstone grit .... 1154 Wendover Down, Buckinghamshire ........ aah sleiele 905 Westbury Down, Wilts ......... aise Avice hee Spa R a 775 Whernside (in Ingleton Fells) Yorksh. Mountain limest. .. 2384 Whernside (in Kettlewell Dale) Yorksh.Millstone grit .... 2263 ‘White Horse Hill, Berkshire ........ Chatk soya ice a's 893 Whiteham Hill, Berkshire ...... Va lactie, 0 bal hae gti Re 576 Wilton Beacon, Yorkshire ......... ii Tae Beh e'a's we . 809 | Wingreen Hill, Dorsetshire........ WEEK 5 Cee Heine: Ek Wittle Hill, Lancashire ....... bic e-hiaddahy etek lee vie in ine eee 1614 Wordeslow Hill, Durham .......0.005 ode ele W ale peer 632 Wirekin, SAropehige iii cis ose Wein cae Sa bee RE SSeS) 4920 Ynaliog Mountain, Caernarvonshire .. Jes Uvies Wariner aes ARTICLE XI. ANALYSES OF Books. Memoirs of the Astronomical Society of London, Vol. II, Pari 11.* The contents of this part of the Memoirs of the Astronomical Society are as follows :— XX. On the Latitude of the Royal Observatory of Greenwich. By John Pond, Esq. Astronomer Royal. * XXI. On the Determination of Latitudes by Observations of Azimuths and Altitudes alone. By M. Littrow, Director of the Imperial Observatory at Vienna, Assoc. Ast. Soc. &c. (Tran- | slated by the Foreign Secretary.) : XXII. Mémoire sur différens Points relatifs ad la Théorie. des ® For the: contents of vol, iis Part 1. of these Memoirs, see Annals for April last. 454 Analyses of Books. [Dec. Perturbations des Planétes exposée dans la. Mécanique Ceélesie. EXIT, My. John R D of his Reflecting Ill. Mr. John Ramage’s Description'o arge Reflectin Telescopes. (With Plates.) dan if Faia > i ‘ d XXIV. On Parallaxes: By J. J. Littrow, Director of the Imperial Observatory, and Professor of Astronomy at Vienna, Associate of the Astronomical Society of London, &c. ' XXV. On the Co-latitude of the Observatory of Stephen Groombridge, Esq. at Blackheath ; determined by his own Obser- vations of Circumpolar Stars, reduced by the Constant of Refrac- tion 58, 133 at 45°. + XXVI. Observations of the Eclipses of Jupiter’s Satellites, made at Futty Ghur, on the Ganges (N. Lat. 27° 21’ 35”) in 1824-5. By Major J. A. Hodgson, Revenue Surveyor General. Communicated in a Letter to the Secretary of the Astronomical ‘Society. XXVIL. A Comparison of Observations made on Double Stars. By Professor Struve. Communicated in a Letter to J. F. W. Herschel, Esq. Foreign Secretary of this Society. , XXVIII. Obisrvadiiie of the Occultation of Saturn on the 30th Ocrober, 1825. By R. Comfield, Esq. and J. Wallis, Esq. | Communicated in a Letter from the former to Dr. Gregory, Secretary of the Society. nas whe adv re XXEX. Account of some Observations made with a 20-feet Reflecting Telescope. By J. F. W. Herschel, Esq. For. Sec. Ast. Soc : comprehending, pene: ae 1. Descriptions and approximate Places of 321 new Double and Triple Stars. ‘Ai | 2. Observations of the-second Comet of 1825. = 9 3. An Account of the actual State of the Great Nebula in ‘Orion compared with oye former Astronomers... 4. Observations of the Nebula in the Girdle of Andromeda. _ - XXX. Explanation of the Method of observing with the two Mural Circles, as practised at present at the Royal Olservatory of Greenwich. By John Pond, Esq. Astronomer Royal. ; XXXI. Extracts from three Letters, addressed by M. Gambart, _ Director 4 the Royal Observatory at Marseilles, to James South, Esq. MAS. respecting the Discovery, and Elements of the Orbit, y, a Comet, which appears to be the same with that of 1772 and 805. Communicated by James South, Esq. XXXII. Report of the Cominittee appointed by the Council of the Astronomical Society of London, for the purpose of examining the Telescope constructed by Mr. Tulley, by Onder of the Council.* XXXII. Micrometrical Observations of the Planet Saturn, made with Fraunhofer’s large Refractor, at Dorpat. By Prof. Struve, Associate of the Astronomical Society off eidde XXXIV. Summary of the Observations made for the Deter- * See Annals, N. Ss vols xis pi 1440, ses 1826.] — Memoirs, &c. of the Astronomical Society. 455 mination of the Latitude of the Observatory of Wilna, By J. Slawinsky, Associate of the Astronomical Society of London. : XXXV. Supplement to a former Paper “ On the Latitude of the, Royal Observatory of Greenwich.” By John Pond, Esq. Astronomer Royal. | Report of the Council of the Society to the Sixth Annual Gene- ral Meeting.* : uy. _ Addresses of Francis Baily, Esq. ERS. President of the Astro- nomical Society of London, on presenting the Honorary Medals of the Society to the several Persons to whom they had been awarded.+ The remainder of the General Catalogue of the principal Stars New Tables for facilitating the computation of Precession, Aberration, and Nutation of 2881 principal fixed Stars, together with a Catalogue of the same reduced to January 1, 1830; com puted at the expence and under the direction of the Astronomical Society of London; to which is prefixed an Introduction expla- natory of their Construction and Application. By Francis Baily, Esq. President of the Society. 1 y } From this work we extract the following, as the severest test of its merit, ee © The preceding Catalogue having been finished, it became desirable to ascertain how far the mean places of the stars, (which had been brought up from the observations of Bradley and Piazzi by means of the proposed formula) could be de- pended upon. With this view a comparison was made with the places of the 36 Greenwich stars, that: have been observed and _ reduced at different times by Messrs. Bessel, Brinkley, and Pond: and which is inserted at the end of the work. | ‘“« There are two Catalogues of the Right Ascension of the 36 Greenwich stars published by M. Bessel in the Konigsberg _ Observations: one (which may be considered as Dr. Maske- lyne’s catalogue of 1805) reduced to 1815, and the other (de- pending on M. Bessel’s own observations) reduced to 1825. Both these eatalogues were brought up to 1830 by means of the annual variations attached to the catalogue of 1825. The catalogue of the same stars by Dr. Brinkley was taken from M. Schumacher’s Astronomische Nachrichten, No. 78: it is there reduced to 1824, but was brought up to 1830 by means of the annual variations annexed thereto. The /irst catalogue, in AR, of Mr. Pond, was taken from. that (reduced to 1819) which is inserted in the Nautical Almanac for 1822 ; and was the last that was published prior to his important alteration of the posi- tion of the equinoctial points by the addition of 0*31 to all the stars. ‘The second catalogue of Mr. Pond was that (reduced to 1825) which is published in the Nautical Almanac for 1829, and contains the latest corrections, to August 1826. Both * See Annals, N.S. vols xis ps 295. + See Ibid. p. 454, 456 Memoirs of the Astronomical Society. (Dre. these catalogues were brought up to 1830 by means of the an- nual variations annexed to the datter catalogue. | ‘*On a comparison of these several catalogues it appears that, as to the Right Ascensions, the catalogue of the Astronomical Society falls far within the limits of the errors of observation : since more than two-thirds of the stars there compared are between the mean places as severally given by these eminent observers: and in those instances where this is not the case, the position does not differ so much from that of some one of the observers, as those observers do from each other, and from themselves. tah “ With respect to the North Polar Distances recourse was had to the two catalogues of Mr. Pond: one reduced to 1818, (being the last correction of his Standard Catalogue of 1812-13, . prior to the derangement of the mural circle) and published in the Nautical Almanac for 1820: the other reduced to 1825, and taken from the Nautical Almanac for 1829, above mentioned. . These were brought up to 1830 by means of the annual varia- tions annexed to the latter catalogue: and which differ, in some instances very considerably, from the values annexed ‘to the catalogue of 1818. Out of the 70 comparisons made, it will be found that in nearly one half of them the difference is below one second ; that in 16 others the difference is below two se- conds; and that in 7 others the difference is below three seconds : whilst the difference in the remainder (which in five cases, only, _ exceeds four seconds) may be considerably reduced by the adoption of the annual variations annexed to the catalogue of | 1818 ; the difference of which will in fact, in many of the com-. parisons, amount to a quantity equal to the whole of: the differ- ence in question. Indeed, a difference in the mode of reduction will frequently account for differences, as great as any that. occur in these comparisons.” . ; The mean difference of each catalogue: from that of the As- tronomical Society is inserted at the bottom of the respective columns’: and will be found as follows : | Bessel, 1815 = — 0%004) 1825 = + 0:15] | do Brinkley, 1824 = + 0-017 re Ascension. Pond, 1819 = + 0:°025 1825 = + 0°351 Pond, ‘eS eo 64) North Polar Distance. ~ 1826.f Proceedings of Philosophical Societies. 457° | Articte XII. : _. Proceedings of Philosophical Societies. apa ROYAL SOCIETY. THE meetings of the Royal Society commenced for the present Session on the 16th of November; when the following business was transacted : | ine | The President announced that his Majesty had presented to the Society the suite of apartments in Somerset House, lately occupied by the Commissioners of the Lottery: he also announced the resignation of Mr. Brande, as one of the Secre- taries of the Society. ) Lieut.-Col. D. Denham, Capt. W.H. Smyth, RN.and Nicholas Brown, Esq. were respectively admitted Fellows of the Society. ‘The Croonian Lecture, On the Generation of the Common Oyster, and the River Muscle; by Sir E. Home, Bart. VPRS.. was read; anda paper was begun, On a Percussion Shell, to be fired from a common Gun; by Lieut.-Col, Millar: commu- nicated by R. I. Murchison, Esq. PRS. Nov. (23.—Charles Bell, Esq. was admitted a Fellow, and MM. Bouvard, Chevreul, and Dulong, were respectively elected Foreign Members of the Society; and the reading of Col. | Millar’s paper was concluded. : , , LINNEAN SOCIETY. - The meetings of this Society were resumed on Nov. 7, when the reading of Dr. Hamilton’s Commentary on the fourth part of the Hortus Malabaricus was continued. : ROYAL GEOLOGICAL SOCIETY OF CORNWALL. Thirteenth Annual Report of the Council. - In’ performing this annual duty, the Council have again the pleasure of announcing the continued prosperity of this Institu- tion. Its progress is indeed slow and unattended by any brilliant transactions ; but it is silently and unostentatiously advancing - in the acquisition of a geological knowledge of our county. - More considerable ‘and valuable additions to our cabinet of native minerals might, from time to time be made, and much useful information might be obtained by minutely exploring various interesting localities, but the limited state of the Society’s funds opposes an insuperable obstacle to the speedy completion of these important undertakings. If therefore this unscientific, but real difficulty, be taken into consideration, the wonder will then be, not how little, but how much has been accomplished. Another year has again elapsed, but the school. of mines is not established: and there appears at present'little probability of the then proposed plan being carried into execution. The Council regret its failure, since the hope of the speedy removal “ 458 Proceedings of Philosophical Societies. [Dre. of a national reproach has been thereby postponed ; but they will not yet despair of the eventual accomplishment of a mea- sure, first suggested by this Institution, and which it has never ceased to recommend. This Society, enrolling amongst its members a great portion of the rank and wealth of the county, should be foremost in promoting an Institution of the first im- portance, both in an economical and. scientific point of view;) and for the establishment of which ‘ one and all” should unite, who are interested in the honour and prosperity of Cornwall. | The Museum, which in the foremost place commands the Council’s attention, has been enlarged by the addition of another Cabinet extending the whole length of one of the galleries: this has afforded sufticient-space for the exhibition of several series of Foreign specimens, which have been arranged by the Curator with his usual neatness and judgment. The attainment of this object will afford but little interest to the scientific stranger ; but to our native students it is of great im- portance, as displaying examples of the various and dissimilar mineral productions of our gone: To our constant and liberal correspondent William Maclure, Esq. of Philadelphia, we are indebted for another donation of minerals from the United States of America ; consisting of various modifications of Ser- pentine, of Augite, Maclurite, Franklinite, Red Oxide of Zinc, and other interesting specimens. - Doctor Jer. Van Rensselaer, of New York, has presented to the Society several earthy and metallic minerals, which are particularly specified in the Cura- tor’s Report of donations, i | wit) Captain Wallis, of Bodmin, has also presented a series of specimens illustrative of the geology of the country between Hydrabad and Madras, accompanied by a descriptive account of the same, together with a map of this part of the penin- sula of India. , : To the kind contributions of several members, in compliance with the request made at the last annual meeting, the geological department has been recently indebted for many specimens of eranite ; but the varieties of this interesting formation are so _ numerous, that many more would be equally acceptable. | The department of simple minerals has also .been enriched by the purchase in Cumberland of a series of splendid minerals, consisting of variously crystallized galena, blende, fluor spar, sulphate of barytes, arragonite, and_other substances. Before concluding, the Council take this opportunity of so- liciting further donations from those members who have private collections : many may have refrained from presenting their spare duplicates on the ground that our Museum already possesses better specimens of. the same kind; these however would be very acceptable, and would enable the Society. to, comply. with the repeated applications that have been made by institutions both at home and abroad, for anexchangeof minerals. ._- 7 \ 1826] Proceedings of Philosophicai Societies. 459 Lastly, the Council propose for the consideration of the general meeting the propriety of expending a portion of their — income in the collection of geological specimens : thereby pro- moting the Society by enlarging the knowledge of our rock- formations and collecting several pieces of the same rocks for the purpose of exchanges. Simple crystalline minerals cannot be obtained to any great extent, but at prices very far exceeding our funds, and indeed such Cornish minerals may be: found in the collections of all extensive mineral dealers. Rock-specimens, however, are not to be met with in such places; but- they can be collected with comparatively little expence; and a series of granite, slate, and serpentine rocks would be the most valuable return the Society could make in their exchanges with scientific institutions. Moreover such intercourse cannot fail of being highly advantageous to both parties, and may be instrumental in the advancement of the science of geology. , . By order, H.S. Boasz, Secretary. - October 13, 1826. i The following Papers have been read since, the last Report :— | On the Granite of the West of Cornwall. By Joseph Carne, Esq. FERS. &c. Member of the Society. ~ On the Sand Banks of the Northern Shores of Mount’s Bay. By H.8. Boase, MD. Secretary of the Society. 3 ~ Some Account of certain Ancient Circles and Barrows on the Summit of Botrea Hill, in the Parish of Sancreed, By T. F. Barham, MD. Librarian of the Society. On the Changes which appear to have taken place in the rimitive Form of the Cornish Peninsula. By John Hawkins, Esq. FRS. &c. Honorary Member of the Society. On the Temperature of Mines. -By Henry Boase, Esq. Trea- surer of the Society. ie! An Account of some Circumstances connected with the Heave of a Copper Lode by a Flucan Veinin the Consolidated Mines, in the Parish of Gwenap. By Mr. W. J. Henwood, Member of the Society. - / On the Geology of the Coast from Sennen Cove to the Land’s | End. By Joseph Carne, Esq. FRS. &c. On asingular Exudation of Gas in the Union Mines, in the Parish of Gwenap. By Mr. W. J. Henwood. | Observations on the Suspension of the Stannary Courts. By Henry Boase, Esq. ee On the Importance of a Deep Adit from the Northern Coast. By R. Edmonds, Esq. Member of the Society. ' A Notice relative to a new Fusee for the Blasting of Rocks. By R. Collins, Esq. Member of the Society. _' An account of the Quantity of Tin produced in Cornwall in the Year ending with the Midsummer Quarter 1826, By Joseph Came, Esq. FRS. , 460 Scientific Notices—Chemistry, (Dec. An account of the Produce of the Copper Mines of Cornwall, ‘in Ore Copper, and Money, in the Year ending me 30th June, 1826. By sINr: Alfred Jenkyns. | Among the presents is the following :— A metallic Pan and Cover, about 15 inches in diuineter, perc ’ atthe depth of 12 feet in an old Stream Work, near St Columb. The metal is very good tin nearly equal to grain. This vessel. was probably used for culinary purposes, and at a period previous to the introduction in this country of the alloys of tin —_ copper and with lead. By H.S. Boase, MD. At the Anniversary Meeting held on the 13th of Oct. 1826, Davies Gilbert, Esq. MP. VPRS. &c. President, in the Chair ; the Report of the Council being read, it was resolved :— That it be printed and circulated amongst the Members : That the thanks of the Society be presented : 1. To the Authors of the various Papers. 2. To the Donors of Minerals, Books, &c. 3. To the Officers of the Society : Lastly,—That another Volume of Transactions be forthwith — . published, and that the new Council be requested to take immediate measures for that purpose. The following members were then elected Officers and Coun- cil for the year ensuing :— President,—Davies Gilbert, Esq. MP. &e. Ke. Vice-Presidents.—Sir John St, Aubyn, Bart.; Sir Charles Lemon, Bart.; William T. Praed, Esg.; Rev. Uriah Tonkin: Secretary. —Henry S. Boase, MD. Treasurer.—Henry Boase, Esq. Librarian.—T. F. Barham, MD. Curator.—Edward C. Giddy, Esq. Assistant Secretary.—Richard Moyle, Esq. Council. —George S. Borlase, Esq.; Joseph Oeiniat Esq. ; Stephen Davey, Esq. ; Richard Edmonds, Esq.; William M. Tweedy, Esq.; Robert W. Fox, Esq.; George Grenfell, Es Michael Williams, Esq.; Humphry Gryils, ais ‘ George B, John, Esq. ArticLeE XIII. SCIENTIFIC NOTICES. CHEMISTRY. : : 1. Method of purifying Crystals. By M. Robinet. Every practical chemist knows how difficult it often is, parti- cularly in the analysis of organic substances, to clear away from crystalline products the mother water, and other heterogeneous. matters, which collect in their interstices. 'Whenthe erystals 1826] Scientific Notices— Chemistry. GG are very fine, and still more when they are soluble in the ordi- nary menstrua, it is sometimes impossible to clear them; although perfectly pure, by any other method than repeated crystallization and digestion with animal charcoal; both of which processes are troublesome, and occasion considerable loss. M. Robinet has proposed a new and very simple method, which was suggested to him, in consequence of observing, that when a parcel of crystals came into contact with the mouth of the prpette during the act of suction, they were instantly and perfectly cleaned. The process depends on the transmission of a current of air through the crystals. He has suggested various forms of apparatus for the purpose. The simplest consists of a double-mouthed bottle, with a funnel in one mouth, and a bent tube in the’ other; the lower opening of the funnel being obstructed by a ball of cotton-wool, and the crystals placed above the cotton. On sucking the air through the crystals by -a bent tube, they are cleaned in a few seconds ; and, if necessary, the operation may be repeated after previously introducing a little water into the funnel. A convenient way of constructing the apparatus so as to work of itself, is to make the second tube reach the bottom of the bottle with one limb, and with the other a vessel of water situated on a lower level. The whole bottle and tube being filled with water, the funnel is to be introduced, and the water then allowed to run off by the syphon. On the large scale a more suitable apparatus will be a tube. from a steam-boiler, by which the bottle may be filled with steam from time to time. petit 3 f - The steam communication being shut off, and the steam in the bottle condensed, the stream of-air will immediately carry through with it the whole of the mother-water from the most silky crystals.—(Journal de Chimie Medicale.) 7 2, On the Decomposition of Cyanate of Silver, by Sulphuretted Ifydrogen. By Dr. Liebig. neces M. Gay Lussac and I have already shown, observes Dr. -Liebig, that sulphuretted hydrogen decomposes cyanate of sil- ver; the cyanic acid is not, however, separated in a pure state ; one part of it combines with the sulphuretted hydrogen, and peculiar compounds are formed which have in genefal the cha- — racters of acids. When cyanate of silver is decomposed by hydriodic and muriatic acid, hydrocyanic acid is evolved, and new acids are obtained which contain iodine and chlorine, and which have the property of giving deep red coloured solutions with the salts of peroxide of iron, after having been neutralized. with a base. With sulphuretted hydrogen no hydrocyanic acid is obtained, and the new acid immediately produces a deep red coloured fluid with the persalts of iron, without previous neu- tralization with a base. 462 Scientific Notices—-Chemistry, - (Dz, - It was also shown in the memoir above alluded to that cyanic acid is composed of an atom of cyanogen, and one of oxygen, and it appeared to us that in the acid obtained with the cyanate of silver and sulphuretted hydrogen, that oxygen was exactly replaced by sulphur, and that we had obtained a compound of sulphur and cyanogen. Such are the results which haye been stated in the memoir; sometime since I undertook some expe- riments to determine with more precision the nature of the acid obtained by decomposing cyanate of silver with sulphuretted hydrogen, The results of these observations are slightly dif- ferent from those which we had-previously obtained, but we have not paid minute attention to these several acids. If vdipbunsised hydrogen gas be passed through water, hold- ing cyanate of silver in suspension, and if the liquor be strongly agitated before the cyanate is totally decomposed, an extremely penetrating smell is perceived, and ammonia, when exposed. to the mixture, produces a white cloud. As soon as the salt is entirely decomposed, which happens when the fluid becomes clear, this atilis no longer perceptible, The liquid separated by the filter from the sulphuret of silver has an acrid. taste, and reddens turnsol ; when mixed with lime ammonia is expelled, it precipitates muriate of barytes after being heated with nitrie acid, gives a bulky precipitate with nitrate of silver, and changes the persalts of iron to a deep red colour; it appears from this that the cyanic acid, decomposed by the sulphuretted, — is converted into a cyanite (?) of ammonia, and. a peculiar acid containing sulphur, but different from the sulpho-cyanic acid. The fluid, when left for some time exposed to the air, deposits a yellow powder, and then the smell of. hydrocyanic acid is perceived ; the solution by spontaneous evaporation yields a deliquescent salt, which, with acid, gives the penetrating smell of sulpho-cyanic acid. | As it is extremely probable that the formation of ammonia had been determined by the affinity of the acid, I made another experiment to decompose the cyanate of silver with sulphuret of barium, obtained by decomposing sulphate of barytes with lamp black; the sulphuret of barium was gradually added to the cyanate suspended in boiling water, as long as sulphuret of silver was formed; the filtered liquor was very alkaline, but it gave no sulphuretted hydrogen on the addition of an acid ; nitrate of silver gave a yellow precipitate, which became black on drying. A current of carbonic acid gas passed through the solution, produced only a small quantity of carbonate, and by | evaporation a yellow salt was procured, which heated to 100° cent. burnt without giving light, till it lost all its moisture, and it became grey: it was then treated with water, which dissolved a sulpho-cyanuret of barium, and carbonate of barytes re- mained: the acids separate sulpho-cyanic and carbonic acids, and lime evolves ammonia. ‘When heated in glass tubes after a Scientific Notices—Chemistry. ; 463 being dried, it fuses, gives carbonate of ammonia and cyanogen, and sulphuret of barium remains. ' 7 When nitrate of silver is precipitated by the freshly prepared barytic salt, a bulky precipitate is obtained, which, after being well washed and heated in boiling water, is converted into sul- phuret of silver, and produces carbonate of ammonia. It ap- pears from this that the acid which is united with these oxides must contain oxygen, besides carbon, hydrogen, and azote. _ When the barytic salt is decomposed with sulphuric acid, a fluid acid is obtained which very readily decomposes. If the salt be pure then no other product is. obtained, but if it contain even a trace of silver, hydrocyanic acidis formed. If the liquid — in which cyanate of silver has been decomposed by sulphuret of bariun. be filtered, before all the cyanate is decomposed, cyanate of silver and of barytes crystallizes upon cooling; this shows that the cyanate of silver loses half of- its oxide, before the eyanic acid itself undergoes any change. Ae If the cyanic acid gives half of its oxygen to the sulphuret of barium, and takes in exchange an equivalent portion of sulphur, the new acid would be formed of two atoms of eyanogen, one of sulphur, and one of oxygen, and the salt of silver, when decomposing at a boiling heat, with six atoms of water would produce one atom of sulphuret of silver, four atoms of car | bonic acid, and two of ammonia. A | r Although these results do not possess all the certainty that is desirable, they prove at any rate, that, during the decomposition of cyanate of silver by sulphuretted hydrogen, or sulphuret of barium, different. products are formed from those which had ~ been supposed, and that the red colour assumed by a solution of a persalt of iron, is not a sufficient proof of the existence of sulpho-cyanic acid, since there are several other substances, differing totally from this acid, which possess the same pro- perty—(Ann. de Chimie et de Physique.) - GT 3. Analysis of Tymp Cinder. In the blast furnaces of the iron works at Merthyr Tydvil, a scoriaceous matter is produced below the opening of the pipes, which is. rich in alkali, and is collected by the workmen, and is used instead of soap. This substance has been analysed by M. Berthier, who states that it consists of small scoriaceous particles, which are black and magnetic, and occasionally inter- spersed with grains of mamellated-scoria; all these are enve- loped in a.very deliquescent alkaline substance; this matter, treated with water, gives : ‘Soluble salts. .......0.6.. 0385 Insoluble matter ........++ O°615 ee 1:000 ~ 464 Scientific Notices—Chemisiry. [Dec. The soluble salts were found to consist of er Carbonate of potash ........ 0°63 Sulphate of potash. ........ 0°37 Silica... .eeeveees »+»a trace “100 There was no muriatic. nor phosphoric acid. The insoluble matter gave by analysis : . da ISIOG.« Sinise sabe 4 ¢ bs hb: cme o., 0 ae Protoxide of iron.......... 0°260 Alumina..... eevee 0040 EGE «cies 1s saws ce ae 0:052 Potash ..-.. ‘dies be Ras 4 4 0°205 Mamellated scoria ........ O°100 1-000 — The alkali is undoubtedly derived from the earthy matter, with which the carbonate of iron occurring with coal is always intimately mixed.—(Annales des Mines.) | 4, Spontaneously Inflammable Metallic Powders. M. Magnus has observed that when the pure oxides of iron, cobalt, or nickel, are reduced by hydrogen.gas at temperatures but very little above that of boiling mercury, metals are ob- tained, which, when allowed to cool in the hydrogen gas, inflame spontaneously by exposure to the atmosphere. If the reduction has been effected at a red heat, this does not take place. | When the same oxides are mixed with a little alumine, the | metals obtained as before inflame spontaneously’ in the atmo- sphere, even though the heat used has been that of redness, and yet from the quantity of oxygen disengaged, it has been eyident that the alumine has not been de-oxidized. _ Hea); ,When a metal, thus competent to inflame in the air, is heated in carbonic acid gas, it loses its peculiar property, but re-assumes “ apes being re-heated in hydrogen gas, and ‘allowed to: cool.as efore. a te oF f Nevertheless, the hydrogen is not the cause of this inflamma- bility ; for when oxalate of iron is heated in a vessel with a narrow neck, so that the acid may be decomposed.and the - whole allowed to cool, the metallic iron-powder obtained in- flames spontaneously in the atmosphere. No other metal. but the three mentioned have presented this phenomena... - is It results from these experiments, that when the difficulty- fusible metals are in a state of extreme division, and. have not aggregated either from adhesion or softness, they have the pro- perty of inflaming in the air. This effect is probably due to a 1826] Scientific Notices—Chemistry. 465 power possessed ‘by these metals of condensing ‘such: quantity of oxygen on.their extended) surface, as’ to occasion the con- ditions necessary to the oxidation of; the metal. . pes The inflammability. of Homberg’s pyrophorus, :prepared. by heating to redness’ a mixture oftsalioen and flour, depends: pro- bably on the same cause; for the: inflammation doesnot, take - place, except when the heat has been so moderated as to be-in- sufficient for the fusion of the sulphuret of potassium. i These phenomena‘are’analogous to those observed by M. Do- bereiner, as belonging to platina, and with the faculty which silicium and zirconium have of oxidating under certain circum- stances, as M. Berzelius has shown. Perhaps, also, they may assist. in discovering the causes of the formation of nitric acid in artificial nitre-beds.—(Annales des Mines, xii.-210.) ‘With these effects should be ranged the remarkable one ob- served by Dr. Gobel, as produced by the residue left upon igniting the tartrate of lead in close vessels. See vol. xvi. ~ p- 385, of this Journal.—Ep.—(Institution Journal.) — 5. Precipitation of a Metal from Solution by other Metals. Professor Fischer, of Breslau, remarks that the reduction of - a metallic oxide from its solution in an acid or alkali by a metal, depends upon the following causes :— 1. Principally the relative affinity of the two metals. for oxygen. 7 ; | | 2. The affinity of the oxide of the reducing metal for the acid, or alkali :—for this reason tin, bismuth, and iron. only reduce a small number of salts, whilst zinc reduces a great number. It - is for the same reason that there are but few alkaline solutions reduced by metals : silver dissolved: in ammonia is not reduced by zinc ; copper dissolved in ammonia is, not reduced: by tin, antimony, bismuth, or/iron. | 3. The electric tension which may exist between the precipi- tating and precipitated metal. 4. The affinity of the metals for each other :—copper is pre- cipitated by iron in a state of purity; precipitated by zinc, a kind of brass is formed. 3 8. The state of saturation and concentration of the solution : —the precipitation is more rapid as the fluid is more acid and concentrated. If the metal is required in fine dendritical crys- tals, the solution should be dilute. Many metallic salts, redu- cible by certain metals when dissolved in water, are not so when dissolved in alcohol. : SE 6. The tendency of the precipitated metals. to assume the gra- nular or crystalline state :—lead, silver, and tin are precipitated from. their solutions more readily than gold or platina. 7. The position of the reducing: metal, relative to, the solu- tion :—when the metal is in plates or wires offering, a large sur- New Series, vou. xit. Qu 466 - Scientific Notices—Zoology. = [Déc. face, the ‘precipitation is rapid’; but when: it \is’ placed atthe surface of the liquor, touching «it only:by a point, it requires'«a long time. Two’ equal’ quantities of solution of silver were taken: a plate of copper was plunged ‘into one;eand a bar of copper made merely to: touch the surface of the other; the:first ‘was entirely freed from silver in‘one hour, the latter not in three months. © Bi Sd abd ts o#S Bost When a zine rod is put ihto a solution of acetate, or nitrate of lead, the first large crystals’ of lead aftera time fall ‘off, and are replaced by smaller, which in turn fall, and are succeeded Piero and this alternate production continues a long time. he cause of this effect appears to be in the power which most metallic solutions have, when saturated with base, of dissolving small quantities of other: metals: thus the ‘saturated ‘nitrate, muriate, and acetate of zinc slowly dissolve a notable quantity of lead; the muriates of zinc and tin and ‘the’ acetate of lead dissolve'a little copper, and the nitrate of copper dissolves finely- divided silver. sca: therefore, a piece of zinc is’ placed’ at the surface of a solution of lead, ‘the latter metal falling to the bottom of the fluid is in part dissolved ‘by the salt of zinc formed ; and ‘the solution of lead'thus formed spreading through the liquid, thus places the zine in constant contact with it; and hence the successive precipitation of the lead which is found to take place. 7 ; OMIT T OSE - If finely-divided silver is put at the bottom of a narrow tube, arid about two inches in depth of a solution of copper saturated With oxide be poured upon it, then a copper-wire plunged to"the depth ofa couple of lines will soon become covered with silver, and in three or four weeks fire crystals of the metal will appear, which will be larger as the tube is narrower.’ ‘It appears, that in all these circumstances double subedity ave! fornaed ; crystals of subnitrate of copper almost always appears mixed with those of silver—Ann, des Mines, xii. 197.—(Institution Journal.) MINERALOGY... thy 6. Bitberg Meteoric Iron. .. According to Stromeyer, it contains iron 81:8; nickel 11°9 ; cobalt. 1-0; manganese 0:2; sulphur 5-1 = 100-0. Bipmeer did not examine it for chrome, but intended to do so.—(Edin New Philos. Journ.) : ZooLocy. . sn ubsiweset ds 7. On Female Pheasants assuming the Male..Plumage: ~The Editor of “ The Edinburgh New Philosophical Journal,” has annexed the following interesting note to a translation’ of M. Isidore Geoffroy Saint Hilaire’s memoir “‘ On Female Pheasants assuming the Male Plumage,” published in the present number of that valuable journal. 1826.] Scientific Notices Zoology. 467 o The interesting fact, of female, birds assuming, the plumage of the male was in. modern times. first attended to by, the cele-, brated. I. Hunter, who; in a memoir-on this subject.in, the Philo- sophical Transactions of London, describes a hen pheasant.and pea hen which had in old age.assumed:the male plumage. . Mr. G,|St. Hilaire, in the preceding memoir, says, that of the many pea hens in the menagerie, in,Paris; no instance occurred of the pea hen assuming the male plumage, a fact which shows sucha, changeiis rarely met with in the peacock. ..In the Museum, of this: University, there is a fine specimen of the pea hen with the male»plumage, presented to: the Museum by the Duchess.of Buccleugh. In theynote accompanying the gift, it is said the change. was effected during the course of a few years. The following description will convey. an idea of the degree of change experienced in this individual. ..The head and neck,;have assumed the same green and blue tints which characterise, the male; the breast and belly also have the same deep colour. . As in the male, the primaries are pale-brown, and a patch upon the wing bright green.;.'The dorsal feathers, however, are still more or less mottled with grey; and the green which they: have, par- tially assumed is lighter than in the male, and not blended with the coppery hue which in his plumage extends ‘from the middle of the back to the rump. The rump feathers are elongated, some of them to the length. of 18 inches, but the train formed by them is. scanty,,and the ocellar spots are neither so,large nor so varied.asin the male. The ordinary tubercles on the tarsi of the female have been developed into thick, regular conical spurs, about half the length of those of the male. In short, the change is so much advanced, that after another month, it would probably have been complete. Ni erpit: Sal pnts Ha In the museum of the, University, thereiis.a-specimen of the female pheasant with the male plumage, presented some, years ago by Dr. Hope.* The only ‘differences which the plumage of this individual exhibits, when contrasted with the tiie bird, are the following : first; the tail feathers are shorter than those ofan adult male, although,considerably longer than those of an ordi- nary female; secondly, the lustre of the colours in general is “not quite so vivid.as in the male, especially on the back ‘of the wings. There isno appearance of spurs. ay te Sometimes the same sort of, apparent change of ‘sex is observed among domestic poultry. Mr. Neill,-at Canonmills, had a black hen, of what is called the French breed, which in her twelfth year ceased to lay eggs, and gradually ‘assumed somewhat the appearance, and, to a considerable degree, the manners ofacock. The principal change of plumage consisted * Inthe British Museum are several similar specimens, particularly two remarkably fine ones, lately shot in Kent, by Thomas Law Hodges, Esq. of Hempsted Place, near ~ Cranbrook, and'by him presented to the Museum,—cC. yo Be" 468 Scientific NoticesZoology.. (Dic. _ in the tuft on the head becoming thinner, and showing some uprignt stray feathers, and in a single elongated feather project- ing from-the tail. The spurs were larger than usual in hens, but these had probably been increasing for some years.. The change: of manner.of the bird was quite remarkable: she strutted about in an overbearing way, with a firm pace and raised tail. She formed a party among the fowls, which she led separate from the ¢ock; and she roosted apart from him. She became very voracious ; and when food was set down (losing all resemblance in this instance, to’ the generous male), she beat off the other hens: when, in these ‘cases, she came in contact with the cock, she stared at him, but without making any attack. . She soon became very fat, and) died within a few months seemingly of - over fatness. _Her-cry was altered, but had little resemblance to the crowing of the cock ; less indeed than is sometimes noticed in young hens. > — | , Le tn a valuable paper, by Dr. Butler, of Plymouth, in the third volume ‘of the Memoirs of the Wernerian Society, there are. many interesting facts on this subject, and from which we extract the‘following table : Table of such Birds as have, in advanced Life, assumed the Plu- mage of the. Male, with the Names of those Authors who have noticed the Fact... he old ) : Orper 4.—Gauin &.—Domestic Brrps. Gen..1. Pavo, Pea-hen .:.... Hunter, Jtirg - 2. Meleagris, Turkey. .. Bechstein. | _. 3. Phasianus colchicus.. Pheasant common: Hunter. ¥ pictus ..... —————— golden: Blumenbach. ; : - Fowl. domestic: Aristotle ott gallus ft _ Tucker, Butler. oe 4. Ley Ton Par- Mester 5. Columba, Pigeon.... Tiedemann. | OrvER 6.—GRALLHE.—WADERS. | | Gen. 1. Otis Busand. Tiede- mann. | 3 Tribe, Gen. 4. Platalea, Peli- can of American: Catesby. 2. Family Pressirostres 3. Cultrirostres <_ Orper 6,—PaLMiIPEDA.—WEB-FUOTED. | 2. Family, Lamellirostres, soft skin on the beak. 1. Anas, Duck, common and wild: Tiedemann. 1826.) —-- Setentific Notices— Miscellaneous. 469 ‘MISCELLANEOUS. “fj joey”. 8. Remarkable Rainbow, : On the 18th. May of. this year (1826), at six o’clock, p.m. lightning appeared in the eastern part of the heavens, and‘‘a little rain fell... There, where it was darker, I, and many of the inhabitants of Lengsfeldst, in Eisenach, observed a very remark- able rainbow. We saw not only, as is commonly the case, the feebly coloured interior rainbow, and the darker coloured exte- rior rainbow, with all their transition of colours, but among these also the following threefold repetition of ‘them in the fol- lowing order: Most exterior rainbow, violet, blue, green, yellow, and red; under a dark layer, and below those with diminished . intensity of colour, first the’ common interior bow, with red, orange, yellow, green, blue, violet; then the following three ; purple, orange, green, violet; purple, orange, green, violet ; purple, orange, and finally, a dull green arched stripe. Karsten _ Archiv.—(Edin. New Phil. Journ.) , | 9. The Moon and its Inhabitants. Olbers considers it as very probable that the moon is inha- bited by rational creatures, and that its surface is more or less covered with a vegetation not very dissimilar to that of our own earth. Gruithuisen maintains that he has discovered, by means of his telescope, great artificial works in the moon, erected by the Lunarians; and. very lately another observer maintains, from actual observation, that great edifices do exist in the moon. Noggerath, the geologist, does not deny the accuracy of the . descriptions published: by Gruithuisen, but maintains that all . these appearances are owing to vast whin dykes, or trap veins, - rising above the general lunar surface. . | Gruithuisen, in a conversation with the great astronomer Gauss, after describing the regular figures he had discovered in the moon, spoke of the possibility of a correspondence with the inhabitants of the moon. _He brought, he says, to Gauss’s recollection the idea he had communicated many years ago to Zimmerman. Gauss answered, that.the plan of erecting’a geo- metrical figure on the plains of Siberia corresponded with his opinion, because, according to his view, a correspondence with the inhabitants of the moon could only be begun by means of + such mathematical'contemplations and ideas, which we and they must have in common. ‘The vast circular hollows in the moon have been by some considered as evidences of volcanic’action, but they differ so much in form and structure from volcanic craters; that many are now of opinion,-and with reason, that - they are vast circular valleys:—(Edin. New Phil. Journ.) : | Is the preceding extraordinary piece of Sctentific Intelligence 470 Scientific Notices—Miscellaneous. [Drc. (under which head it appears as above) a quiz, or are Messrs. Gruithuisen, another Observer, and Noggerath, downright luna- tics? As to the alleged conversation between MM. Gruithuisen and Gauss, the latter must, we conclude, have intetided to laugh in his sleeve at the strange speculations of the former, whilet he seemed to enter into his wild, extravagant views.—E 10. Transmission of Sound. The extreme facility with which sounds are heard at a consi- derable distance in severely cold weather, has often been a sub- ject of remark; but a circumstance occurred at Port Bowen, which. deserves to be noticed, as affording a sort of measure of this facility. Lieutenant Foster having occasion to send a man from the Observatory to the opposite shore of the harbour, a measured distance of 6696 feet, or about one mile and two- tenths, in order to fix a meridian mark, had placed a person half-way between to repeat his directions; but he found on trial that this precaution was unnecessary, as he could, without difficulty, keep up a conversation with the man at the distant station.—(Parry’s Voyage.) » ; | “11. Unprecedented Cold. | Plattsburgh, Feb. 22, 1826.—On Tuesday and Wednesday of last week, was the coldest weather probably ever experienced in the United States.. We did not ascertain how low the thermo- meter sunk in this place; but at Fort Covington, fourteen miles distant, a thermometer sunk to 40° below zero, and the mercury froze! How much lower an alcohol thermometer would have sunk is not known; probably, however, not more than one or’ two degrees, as mercury exposed at the same time was a long time in congealing. A degree of cold sufficient to freeze mer- cury was never before noticed in the United States, and probably never in so low a latitude as 45°, The coldest weather that we recollect to have heard of im this country was 32° below zero.— (Intelligencer. ) ise : gore 12, The Heat of July, 1825. The heat of July, 1825, seems to have been as oppressive in England and France.as in this country, and to have been attended in. some: instances with the same fatal effects, as a number of sudden deaths are mentioned in the papers. ‘The thermometer stood at Bath on the 19th, in the shade, at 89° ; and the number of horses that had died is supposed to be greater than at any former period. The effects of continued hot weather were seriously felt... Brooks and ponds were become quite dry, and vegetation was suffering from the scorching heat of the sun. The weather in Paris was most intensely hot, and such a season has scarcely ever been remembered there. Nearly a period of twelve weeks elapsed without a single drop of)rain, and the 1826.] 3 : New Patents... 471, papers represent the country as absolutel burnt up. The ther- mometer of Fahrenheit was daily as high as 90°, even in cool parts of the city, and was in many places between 90° and 100° throughout the day, The waters of the river Seine were extremely low indeed, —(American Journal of Science. Srp -ArticLe XIV, — NEW SCIENTIFIC BOOKS. | PREPARING FOR PUBLICAT ION. Early in December will be published the Zoological Journal, No. 1X. consisting of papers in various departments of Zoology,’ with ‘some Account of the Life,’ and Writings, and Contributions to Science, of the late Sir’T.’S. Rafiles, Knt. FRS. &e. President of the Zological Societ Mr. Varhday hi has in the press an octavo volume, entitled, ‘* Chemical “Manipulation,” containing Instructions to Students in Chemistry rela- tive to the Methods of performing Experiments. Mathematical and Astronomical Tables, for the Use of Studente.i in Mathematics, Pens Engineers; Naragatorys &e. ey W. Gal- braith, M A. | JUST PUBLISHED, : Genlogttal ‘and Historical Observations on the. Bastem Valleys of Norfolk ; by J:.G. Robberds, jun. 8vo. 4s., Dewhurst’s Dictionary of Anatomy. 8vo. ‘Part lL 5. 6d. Hamilton’s Outlines of Midwifery. 8vo. 7s. 6d. Burrow’s Conchology. 8vo. 16s. plain, or 1/. 11s. 6d. adh"! ‘ Lamarck’s: Lencholagy illustrated. Part IV. 1. 11s, 6d. pai or 31. 3s. coloured. , Illustrations in Ornitholog by Sir W. Jardine, Bart. FRSE. ‘&e. and Prideaux John Selby, F ELS. &c. Part I. “yen Daubeny's Description of Volcanos, 8vo. 16s. : Phillips's Outlines of Mineralogy and Geology. 8vo, 8s. Gds> Memoirs of iio London Astronomical Society, Vol. im. Kons T1.$0s / ee XV. _ NEW PATENTS, B. Newmarch, Cheltenham, for improvements on fire-arms. Q1\, 29:55 | 29°52 29535 | 60 }.50| 550] - NW |Showers. | 29°93} 29-98 |29- 980 56 | 50 | 53°0°| 060 | NW [|Fair. ~~ 29| 29-98] 29-97 29-975, 60 | 50 | 55:0 NW |Fair. “6 80} 29-96] '29-90]29-930 |) 58° }.53. | 0555 /'W |Misty rain, . $1).29°98| 29-96|29-970, 55 | 48. -5i-5-| | | NW-|Fair 3: showers. - Noy: 1) 29°71] 29-70|29°705) 50 | 57.) 53:5 _..| NW. |Showers. 3 29-78| 29-74|29-760| 52 | 47-| 49-5 | N__|Fair.. 3} 29-16] 29-76|29°760' 55] 44} 49:5 |) NE Fair. 2 A) 29°76| 29°68|29°720) 54] 48°) 51-0) ©) NE Pair ; showers, 5] 2971 29°70|29°705| 54 | 48 | 51-0 NE_ |Fair ; showers. 6} 29°T2} 29°70|29°710| 54°) 48s 51-0 fie. N {Fair ;> showers. 7| 29:92] 29:30]29-860 48 | 36 | 42:0|. - | -N ;|Showers. 8} 29-96] 29-94|29-950!' 51 | 36'| 43-5 | | NW [Fair. ‘ 9| 29-99] 29-98|29-985 |'52-|.38 | 450.) °° | NW [Fairs ‘showers. | 10| 30:00} 29:98 29-990... 54. | 38°/:46°0 |. 0 vo NW» {Fair ; showers. 11} 29°70] 29°68 |29°690) 54.1 40 |..47°0)100 5 fo Wy {Raine ose 12] 29°49] 29-4) |29°450, 54-| 47 | 50-5.| 0°15 .| W..|Showers... , 13} 29°10] 28°70|28'900 55 | 46 | 50-5 “| SW |Rain. 14} 29-50] 29-10]29-300 52] 44 | 48-0 |) N {Hail showers. 15| 29-70] 29°62|29°660 | 52 | 46 | 49-0 | 0-20 | NW |Showers. 16} 29°68| 29°66|29-670; 51 | 38 | 44:5 SW |Rain. ~ 17| 29°74] 29°73|29°735| 50 | 44 |..47-0 'W_ |Showers. - 18} 29°92] 29-91|29-935 50 | 38 | 44-0 | 0-08 | W_ |Showers. 19| 20-00] 29-92|29-960! 50 | 42 | 46-0 | © NE .|Clear 5. fair. 20 30-15] 30°14|30:145| 49 | 43 | 46-0 | NE |Fair. 2i) 30-22]. 30:20 |80°210 48 | 43°) 0455 © |) NE: |Pair. 22] 30°20] 30°15|30-175 | 48 | 38 | 43:0 NE |Fair. | 0-22] 28-70|29-758 64 | 36 | 50-0! 1-130] NW RESULTS. Barometer, méan Reight 2. .vueLeteadoelodes oiibis ‘4 Register Thermometer, ditto .....0se.e,s0++ ++ 500°C Rain, No. 1, 4-130, No.2, 3°020. : Prevailing wind, NW. BS en; ee No. 1. This rain guage is fixed on the-top ofthe Museum |of the Royal zi Geological sf of Cornwall, 45 feet above the ground, ‘and 143 above the level of the sea. No. 2. Close to the ground, 90 feet above the level of the sea. ; Penzance, Nov. 24,1826. > , : EDWARD C, GIDDY. 1826.) ~° Mr. Howard’s Meteorological Journal. 473 ArTICLE XVII. METEOROLOGICAL TABLE, a BAROMETER, THERMOMETER, . 1826, Wind. Max. Min. ‘Max. | Min. | Evap. | : Rain. 10thMon. i Oct. 1} Var. 30°09 29°96 | 68 39 — 04: 2, FE 30°09 30°04 68 45 — . 3) W: 30°04 ~ 29°93 62 45° os 4i\N.. W] .29°95 29°93 ‘68 135 —_ 5IN Wi 30°27 29°95 6° | 29| — ' 6\S Wi 30°27 30°96 55 28 — 71S Wi 30:27 30°08 64: 4:4 — — 8iS Wi 30°07 29°97 63 50 — 16 9| W 29°97 29°86 57 43 — Q7 10S W 30:18 29°86 65 55 co 07 118 W| 30°23 30°18 66 59 — 12:58 W| ‘30°23 30°17 66 —_ _ 1318 . "Wy 3020 | 295 | —4-— | — 14, § 29°95 29°63 — _ — 15S E 3017 29°78 67 40 _ 16S E| 30°14 30°79 67 34 "90 a 1718 E} 30°14. 30°11 61 42 — he EB | 80°13. | 80712. 7 62 bi Be hee Le 19)S E| 30°13 30°11 62 58 — ‘iad as 20\S E| 30°11 30°10 62 55 _ 2118 E} 30°10 30°09 71 51 _ 22/8 E| 30°09 30°05 65 53 — 53 23\58 E| 30°07 30°05 | 65 50 — 20 94S Wi 3007 | 2960 | 62 | .53 | — 29° 2558 Wi 29°60 | 29°60 59 42 _ 05 26IN. W| -29°77 29°60 51 37 — — 2715 Wi 30°25 ITT | BA 40 — 25 23IN Wi 30°32 30°25 54 41 — : 29IN Wi 30°32 30°28 53 49 oe 02 30|S E} 30°28 | 30°24 55 47 _ 31IN W|. 30°24 29'94 53 40 65 30°32 29°60 71 28 1°55 | 2°05 ‘The observations in each line of the table apply to a period of twenty-four hours, the result is included in the next following observation. beginning at 9 A. M. on the day indicated in the first column. A dash denotes that 474 Mr. Howard’s Meteorological Journal. [Dec. REMARKS. Tenth Month.—1, A heavy shower about'two, p.m. 2—5. Fine. 6, Foggy morning: day fine, .7. Day fine: rain at night. 8. Cloudy: rain at night. 9. Cloudy and fine: night rainy. - 10. Morning rainy : afternoon cloudy. 11. Cloudy. 12. Cloudy. 14, 15. Fine, - 16. A heavy shower of rain, with thunder, about two pm. 17—19. Cloudy. 20, 21. Fine. 22. Rainy., (23. “A thunder storm about one, p.m. : lightning in the evening. 24. Fine day: rain atnight. 25. Cloudy and fine. 26. Fine. 27. Rainy. 287 Cloudy. (29, 30. Cloudy. 31, Fine. ac A a ey C< - Nm RESULTS. Winds: E,2; 8,1; SE,9; SW, 10; W,2; NW, 6; Var. 1. Barometer : Mean height For thermnnth. £2. .dve.k | Beane htc Gs oome eencove 30-064 inches. Thermometer: Mean height For the Ogee lati pall. 277 MPa dig B ye NS 53°105° Evaporation, 22. 5}.0c5ttse'd ss ee veadeve’ vo cceccboedas eeres eerecte 1°55 in. petted SSS ff eeee @ereeeerererrere e@ere-weee Oe occccoes vedédoccets eee 2°05 Laboratory, Stratford, Eleventh Month, 24, 1826. | R. HOWARD, INDEX. yee * Sega suiangaly on, Academy of Sciences. at Berlin, plan for making a minute survey of the bisa under the direction of, 124. : Acetic acid, on the production of, bake Acid, bromic, its combinations, 417, Acid, new, produced by the mutual action of sulphuric acid and naphthaline, 201 —— sulpho-napthalic, analysis of, 215." Acorns, analysis of,,.43. 1)... Africa, Southern, on the serpents of, 237. Aikin, Mr. on the geological structure of Cader Idris, 145. Air, atmospheric, method of determining ' the quantity of vapour in it, 97. Air-pump without artificial valves, 153. Alcohol, derived from the fermentation of bread, 363. Ammonia, hydrobromate of, 413. Analysis of acorns, 43, ——- of halloylite, 391, of. polygminite, 117. of some minerals, 116... ‘ ‘Analyses of Books, 52, 134, 215, 226, Animal magnetism in France, 135. Seales ae on the PURI WIOS and boring of, Apparatus, electro-magnetic, pani one, 357. Arctic expedition, intelligence from, 149. Arsenic, detection of, 391. Astronomical observations, 52. Atmospheric. air, method of determining the quantity of Ni they ati 97. B. » Babbage and Herschel, Messrs. on the magnetism manifested by various sub- . Stances during rotation, 183, 246. Balard, Mr. on a peculiar substance con- tained i in sea water, 381, 411. Henny, Col. astronomical obetrvations, Bell, Mr, on the nervous. circle which : connects the voluntary muscles, with the brain, 226. Berhiee M. analysis of tymp ie Berzelius, M. analysis of. miierals by, _116-—analysis of hosphate of ttria, _116—analysis of polygminite, 17. Biographical notice of iM. Proust, 241. —-- Dr, aE iff Bitberg’ meteoric’ iron, , 466." ; Bog, butter in, 75. : Bonnington, near Leith}! fodine found i in the mineral spring of, ” 390. - Books, analysis ¢ of, 52, 134; 215,226, 453. new scientific, 76, "156, 239, 316, 394,471. ° k Boulders, remarks on, 314. ' Brayley, Mr. on the rationale of the form- ation of the filamentous and mami varieties of carbon, and in the probable existence of but two distinct states of aggregation in ponderable matter, 192. oat » baking of, chemical essay on, 161, 263. fermentation of, alcohol derived from, 363. Brome, a peculiar substance contained i in sea water, 381, — action of; ; ‘it metallic ‘ oxides, 16 Brome and chlorine, compound of, 420. ——— hydrocarburet of, 422, natural history of, 423. Bromic acid, its combinations, AlT. Bromuret of gold, 416. iodine, 420, —————— phosphorus, 420. Bromuret of platina, 416. ———-—— potassium, on, 412. — lead, 414. —__ ——— mercury, 415. silver, 415. sulphur, 420. Butter in a bog, 75. C. 2 Cader Idris, on the geological structure of, 145. Cafein on, 354, 889—composition of, 3 e 476 Carbon, on a new form of, 1. filamentous and *mamiilai ¥> OL, &e. 192. — Sis: on the inspiration of hydro- Pa sD ag new, of the fall of stones, iron, dust, and soft substances, dry or moist, in chronological order, 83. Chladni, M. catalogue of the fall of stones, iron, dust, and soft substances, dry or moist, in chronological order, 83. Chlorine and olefiant gas, spontaneous combustion of, 312. Chlorine and brome, compound of, 420. Christie, Mr. on the magnetism “of iron arising from its rotation, 27, 106—on the magnetism developed in copper and ‘other substances during rotation, 253. Christison, Dr. reply to Mr. Phillips, 23 er Phillips’s answer to his reply, Cinder, tymp, analysis of, 463. Circle, luminous, round the moon, 236. nervous, which connects the volun- tary muscles with the brain, 226. Col profuced by the combination of 3 e : Cold, unprecedented, 470, ee Mr. on cutaneous absorption, Colquhoun, Dr. on a new form of carbon, 1—chemical essay on the baking of bread, 161, 263, Combustion, 426. Combustion, s 2 ea of a mixture of __ chlorine and olefiant gas, 312. Copper, on the magnetism developed in, ‘ during rotation, 253. Croonian lecture, by Sir E, Home, 134. Crawford, Dr, on the semi-decussation of the optic nerve, 315, Crystallization of sulphur, 148, Crystals, on the pu tion of, 460. Cutaneous absorption, on, 154. “Dp. Daubeny, Dr. analysis of his work on active and extinct volcanoes, &c. 215. Davy, Sir H. on the relations of electrical and chemical changes, 62. De France, on a recent species of the genus hinnita, 103 Devtosbuieinnds of tin; 414. Dies, steel, on the burdening of, 154. Dobereiner, on the cold produced by the combination of metals, 392. . Index. . Dobson, Mr. remarks on bowlders, 314. Drummond, Lieut, on station lights, 74. E. eee strata of, on the consolidation of, Edueation, chemical, ‘suggestions for phe improvement of, 369. et ates apparatus, improved, on; Emmett, Rev. Mr. account of a curious phenomenon observed in the moon, 81 —telescopical observations on the moon, 335, 434—on oy ean rae 426—on ga- seous bodies, 434. Encke, M. letter to Mr. Herschel, 129, quoter, length of the pendulum at, 281, 4 FEF. “Fallowes, Mr. on the small transit instru- ment, 230. Faraday, Mr. on the confinement of dry gases over mercury, 388—on fluid’ sul- phur at common temperatures, 390—on the mutual action of sulphuric acid and napthaline, and on a new acid produced, 201—on a limit to vaporization, 436. Fermentation of bread, alcohol derived from, 363.. Fossil megalosaurus and didelphia, okdar - rence of, 155. Fractions, continued, on the use of, with restricted numerators in gore a of series, 48." Franklin, Capt. and Dr. Richardson, in- telligence from the land arctic expedi- tion under, 149. i Friction, on the heat of, 260. _ Frog, heart of, used’as a poison, 156. «he Garot, M. on the peepantinnce of yon oid 889. ° ; "Gaseous bodies; on, 434. Gases, dry, on their confinement over mer- 388. —=— ‘method of determining their spe- cific gravity when mixed with moisture, 97. oe , Index. Gate on the absorption of, by liquids, Piso pas M. report upon the memoir of M. Balard, 425. Geckoes, used in catching flies, 237. Genus hinnites, further observations on,’ ; 361. - Giddy, Mr. meteorological table, 78,158, 240, 318, 396, 472. Glass-making, ’ on the use of sulphate of | soda and common salt in, 148. Gold, bromuret of, 416. Goldingham, Mr. on the length of the pendulum at the equator, 281, 342. Graham, Mr. on the absorption of gases by liquids, 69—on the alcohol derived from the fermentation, 363—on the heat of friction, 260. Gray, Mr. further observations on the genus hinnites, with the addition of another recent species, 361—on the digéstive organs of the genus Comatula of Lamarck, &c. 392—on a recent spe- cies of the genus hinnita of De France, - and some. observations on the shells of the monomyaires of Lamarck, 103, Gypogeranus,. its manner of destroying serpents, 237. ~ H. Hall, Sir James, on the consolidation of the strata of the earth, 299. Halloylite, analysis of, 391. Haslan, Dr. on a new species of American quadruped, 238—on a new species’ of salamander, | inhabiting sion 815. Heat, excessive, of 1825, notice “of, at Brooklyn, New York, 120. —— of friction, on the;. 260. — of July, 1825, account of, 136, 470. _ —— radiant, on its eer ‘through’ glass screens, 61. - — remarks: on Mr Ritchie’s experiments on, 13, ——-— remarks on the Rev. Mr. Powell’s paper on, 122... Heavens, survey of, plan for making a minute one, 124. Heberden, Dr. account of the heat of July, 1825, 136. Herapath, “Mr. © method of determining experimentally the quantity of vapour in the atmosphere, and the specific gra- vities of gases mixed with moisture, 97. Herschel, Mr. account of a series of obser- vations ‘made in the summer of 1825, for the purpose of determining the differ- ence of the méridians of the Royal Ob- 477 servatories of Greenwich and Paris, 138 —letter to, from M. Encke, 129, Home, Sir E. Croonian lecture on- the "structure of a muscular fibre from which is tie its elongation and coritraction, 134, Horner, Mr. on the use of continued frac- tions with unrestricted numerators in summation of series, 48. Howard, Mr. R. meteorological tables, 79, 159, 319, 397,473. ' Hydrobromate of ammonia, 413. barytes, 414. magnesia, 414. Hydrocarburet of brome, 422. Hydrogen, inspiration of, effects of, 149. Japan, islands of, account of volcanic eruptions in, AAS, Inspiration of hydrogen, effects of, 149, Institution, Royal, proceedings of, 67. Todine and brome, compound of, 490. Todine, found in the mineral spring of Bonnington, near Leith, 390. Treland, NE of, geological position of some "rocks, 67. Tron, magnetic effect produced in, and ~ in other metals by rotation, 27, 106, : 183, 246, Tron, meteoric, Bitberg, A66. . K. Kater, Capt. abstract of his paper on the _construction and adjustment of the new standard weights and measures, 53. L. Lamarck, observations on the shells of the ° monomyaires of, 103. Lead, bromuret of, 414. Lead, tungstate of, 364. Lecture, Bakerian, on the relations of electrical and chemical changes, 62. ---—--— Croonian, by Sir E. Home, 134. Leslie, Prof. on the light and heat of the solar spectrum, 234. Levy, Mr. on the tungstate of lead, 364, Levyine, analysis of, 117. 478 Liebig, Dr. on the decomposition)of cya- = « silver by pulptanatian hydrogen, Lal ‘on the freshwater strata of ep, the Beacon and Barton ert Hone 68. Maenenees ssa in LF rane, 183... the,, darslaped: ‘during the rotation ee copper, 253. ———- produced by rotation, on, 27, 106, 183, 246. ~— M. on spontaneously inflamma- metallic powders, 464. Meconiate of morphia, 148, ene Aidelphis, fossil, occur. “ion on..the law, of ccaPA 3i32 anes Mercay, bromaretsof 415... cath Mera, the pa eee i Metal, precipitation ,of, by ‘other metals, Metallic powders, spontaneously, inflam- mable, 464. aoe combination, cold inch by, ues luminous, 15. Meteorological table, 78, 79. Miller, Mr. addition to the list of sub- stances that cause a coil platinum wire to remain red-hot when ignited in their bag 20—on the oxidation of palla- its faite the, union of eye bi Piss otmon og re uc- Minerals, analysis of some, 116. Moon and its inhabitants, 469. Moon, curious Foeygnenn observed in, 8l. —— telescopical observations on, 335, 434. —— luminous circle round the, 236, Morphia, meconiate of, 1484::0) 9 Muride, a supposed elementary substance; properties of, 311, see Brome. N. ah iG ‘i Ua Napthaline and alginate acid, on their mutual action, 201. Index. ef or? ols: eds .q y t Gu, i) wogu joges Be, } Ghesrvatories of isha, Bass, difference of the longitudes of, 138. :«\ Olefiant igas_.and_ chiorine,. spontaneous combustion of a mixture of, 312... © Opie netve, aE TE: of, Osler; Mr. on the burrowing and borin of antinale; 1GEE ifae 10 , ae seated action of brome. on, P. itt oomeane _ iw Palladium, on the oxidation of, during its its _ effecting the union of h cand ogen gas‘from ether, alcohol, &c.:20.. Patents, new, 17,0156, 289, a 395, Pelletier, M. on-eafain, 354... Pendulum, length of, at the equator, 81, 342. Pheasants, female, on their assuming the male plumage, 468) Phillips, Mr. R. reply to him by Dr. Christison, 23—his answer to Dr. noes - tison’s replys: 335. - x14 Mr..W. altitudes of hills and, ie tions of England and. Wales, and Ee the nature of their constituent em 6 1 Phosphate of yttriayanalysis of, 16e\. a Plan for er a uninate eter coin ie sno (oe J8 ° pres ignited nat; Poison, onokaneteten poste ajx 156. Polygminite, analysis of, 117.— bape Lieut. notescon«the geological of some rocks of the inane of Ireland, 67. Sao of; 412: abt eds" ow Rev. Mr. on some. ts - gelative to the: passage of. experimen _ through glass:screens, 61—remarks on - his:paper on radiant heat, 122—remarks on Mr. Ritchie’s expenimnanty on radiant - heats 13, >» Printing, stereotype, improved method of, a M. biographical notice of, 24. Index. P ut, Dr.) rematks on: the observations of essrs,) Levitet) and: ‘Lassaigne, and » Professors Tiedeman and Gmelin, 405. Pump, air, without artificial valves, 153. @ Quadruped, American, new species of, 238. OR. Radiant heat, on its passage through glass screens, 61. Rainbow, remarkable, 469. Rattle snakes, taming of, 156. Ritchie, Mr. remarks on his experiments on radiant heat, 13—remarks on the Rev. Mr. Powell’s paper on «radiant heat, 122—on an air-pump without ar- tificial valves, 153. . Robinet, M. on purifying crystals, 460. Rotation, on magnetism priduced by, 27, 106, 183, 246. Ss. Salamander, new species of, i Pennsylvania, 315. Salt, common, on the use’ of, in glass making, 148. ° Sea water, peculiar substance contained in, 381. Serpents, of Southern. Africa, on the, 237. Silver, promurét’ of, 415. : Silver, cyanate of, decomposition of, by sulphuretted hydrogen, 461. Society, Astronomical, proceedings of, 141, 230. notice of the papers contained in the memoirs of, 453. Geological, ‘proceedings of, 67, 145, ——. Linnean, seasosedings of, 143, 457. 147, 387. Royal, analysis of Tranaiowons of, 52, 136, 226. proceedings of; 61, 457. Medico-Botanical, proceedings of, . 479 Society, Royal, Geological of Cornwall, report of, 457. Wernerian, proceedings of, 147. Soda, ‘bicarbonate of, its reaction on'sul- phate of magnesia, 403%. «::: Js Soda, sulphate of, on hie use of in plas ov making, 148, HLL 4 OP iio Ya irqati ‘ «anhydrous ADL.) 20 Solar spectrum, onthe light and heat of, 23 Sound, transmission of, 470. Spectrum, solar, on the light and heat of, 23 Station lights, on, 74. Steel dies, on the hardening of, 154. Stephens, Mr. suggestions for the i improve- ment of the British system of chemical education, 369. Serer printing, improved method of, ' ’ $52. Strata, freshwater, on, 68. Sturgeon, Mr. account of an improved electro-magnetic apparatus, 357. Substance, peculiar, contained in sea water, 381. Sulpho-napthalic acid, analysis of, 215, Sulphur, bromuret of, 421, Sulphur, crystallization of, 148. — fluid, at common temperatures, 390. Sulphuric acid and napthaline, on their mutual action, 201. Survey of the heavens, plan for making a minute one, 124, T. Table, meteorological, 18, 79, 159, 240, 318, 319, 396, Temperature, law of, on the, 366. Thenardite, a new mineral salt, 313. Thomson, Dr. on anhydrous sulphate o of soda, 401. Tin, deutobromuret of, 414, Transit instrument, small, on the, 230. Tungstate of lead, on the, 364, Turner, Dr. on the detection of arsenic, 391. Tymp cinder, analysis of, 463. V. Vaporization, ona 5 limit to, 436. Vapour in atmospheric air, method of de- termining the quanity of, 97. Ww. ee ec teevernrannayt 27 Index. _ Woodhall, Rev. Dr. notice of the ature at Willitm’s ( )» . during the summer: 5 121—notice . of the excessive heat: at Brooklyn, New York, 120. 4 ‘1 - Ye '¥ttria, phosphate, analysis of, 116. — END OF VOL. XII. _» Printed-by C, Baldwin, New Bridge-street, London, oii Bre aoa pean any me be ees Be « “2 . Sa re ee ee od od _ ~~ 8 S53 a ke Te ‘Cais - E ay, As SKE he d fi ~~ NAS Peet =v %. < re a a ba) a ca tee Ps “ Le a hates . : a>: a neat . | . Sie ANAS ASSIS Seon LUE EE