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yfiKITISH ASSOCIATION av»A"NrSEA. ( Continuedfrnm our hrst.) y! Sir H. S. D- L1 Berhe read a.ptper on the Geology of oortions 01 South Wales. Gloucestershire, and Somer- setshire." Mr. Benson then read "A short description of the :ph- tive position of the various qualities of coal in Sooth Waies COIl fields Tla. varieties of coal found in the mineral basin of South Wiles may be divided under three character* 1. The Bi turn in us-tlie small of which win coke. 2. The Free-Burning—thesmall af which will not coke,? but winch burns with great rapidity, and a considerable volum" of flame. y. The Anthracite, or stone coal. Bat these three i rincipal characters of the coals of South a.es are not distinctly marked in their extent or limits; is in the same vein of co*l there is often a gradual change tntm the bituminous to the fre«-baming; so between the tree-burning and stone-coal en the north side of the basin is a considerable extent of culms, which iodine the free- ournmg quality of emitting fume, are still without the value and proportions of carbon of the true stone-oal. The accompanying man Tins been coloured merely with The accompanying man Tins been coloured merely with the view of illtistratin,- the position and extent of each quality of coal, as likely to be interesting to non-resident members of the Association. I n a district of the extent of the Welsh coal- field, where faults and anticlinal lines have materially shifted portions •ot wems from their original positions and of which so hree jt^proportion is yet unworked.it would be impossible to describe exactly the quantity of each vein of coal. I. therefore produce the map as affording only a .r. n.-rat cuH.ne of, at the same time I believe the description to be sufficiently accurate for the object desired. Yellow describes the bituminous coal, and, as a general ^Se„dTribe<i hi*h,y bituSoui ,on the south crop, gradually becoming less so as the veins approach the north. Thus in the five feet vein which has been exten!!ively worked in the neiJOthbourhood ot nmfj I ue south 8,<le ,he vein wa« 1'izhly bitumi- "f "womil«. "° r'Se free'burninS with»" a distance 1vtolihthJeU(7 mkrS *1^ ,he Pink' 80 the coalsgradual- ly thf Thirty «f coking In close ovens. Manv of adapted tCr 8 v°ng'-We11 a^aPted- perhaps better t and in »K 7!re brtu,n°us» for smelting purposes, Ply for the hla'gf f°Urhood-°f Merthyr« form l'le chief sup- or tt fc ^n?ces>rr.I,lcl! they are either used The niitlr 'fiJT ls.coa ln tbe °Pen air for use. winch ^ELJNJFJF Purer,8.orts « free-burning coal, •<outainlne!somp n P» for ™eh'n* purposes than when l tr«o of thp«JnnePor.tlon of the hi uminous quality. The iu eaL^ t PreKerTcd f°r marine «eam engines from Its readiness rf corubustion, and the absence of clink- erli in the ¡1;rate. -drawn'Lwhff "ap ,^as coloured my attention was not free-burnina coal" th,rouSh the basin which the Llanvenneph r t0 government contracts, viz., •nd Aberdare, ar^placed'. Brind°Wy' Resolven' 1*wC^hew«ethee"bt,r"'ng Cr°a'' tfle P'1 merging into POg,,non, 0,f vfrious cu,.ms» before we -near Hirwain hiit i? whilst the last, which commences ■true an hracTi; nntilT n0t appfar t0 attain the quality of ,he Ne*,h «Pmar to ronfef""0- thf re,?aininf? portion of coal would aKe of vXlen,irely,°f anthracite and culms. The "tion to the nmhiM j'1 ln- l',at district attracts atten- ~.i *« £ :fe,l''g,! F°r'io"°' ,he on the'eas^ancHC "IT3*?!the Coal he,d between Pontypool s"a woukl form ™ e,ly; ,?ere crops merge in the proportions Z,ia °f 750 1?uare mile*> °f which the coaFaTfree coal TMT t0^~c?Y^ coal, smelting •Wclusiv^ftf »HA P' I! I F- • 2-45; stone coal, 2-15; The remaiJdefoS portion of the coal-field, the coalTnd th/nlt PrPf re.ferred to t,le direction of Xillybebill After^U"d 0n the nor,h croP of •!» Ckw^^S2"V?eBTli7 Hof^ •i0 that he ventnr»i i L concluded by stating, that they would leadlo th suggestion8 with the hope the cause he d,scovery of a true solution of a of Cannel Coal found in a vein of common Bitu. minous Coal." Beeche' Sje Vlr rTquest of Sir "e"ry De la respectinge.xceetJm?'y interesting information Wales, and al«n\lijtlCS • Mineral Basin of South was written 25ft „ ad Coplo"S e?,'racts fro«> a paper which was wrttten 200 lears ago by a Welsitman, named George Owen, who was Lord of Cemaes, in Pembrokeshire. The given bv him of 8t y f Wr'ler* and 'be description ous ve-tJnoin i cour*e of the minerals, with the vari- the views takelThl,0nSr formed a strong confirmation of Mr. Benson • y,e.m,nent geologists in the present day. South Wales Ra n b,s Pa.Per'aken the gross area ot the few vears In-n^1*1? Mi,!eral!i at 750 square miles. A each sauare mll^r" ^?r".n h ,d stated tI,at the contents of coal filr I!], be estimated at 61,000,000 tons of Saremif«TU0n: fnd takir'8 the gross a^ea at 100 the nmoT.nt f y wo"ld have for the purposes of life the if th,T mnltL?1^,y u hundred millions of tons. But estimated^ on amount by 7j-to arrive at the whole amitaT Mintain 1,1 s<luare miles—the indeed M? R av^,Iab[e for exhaustion would be great was ll l .f the,n referred to the rate at which coal tbe ^esent day- Sir Jolln Guest used 1,400 inc dav= iPeV^y/^1',ch bein^ multiplied by 300 work- in a vlar «r? tons as the quantity used by him mineral k • 1-n *ere already within the confines of this basin log blast furnaces for smelting iron those furnilces produced 550,000 tons of iron a year; the coal 1 111 sme't,nK t'"1 quantity of iron amounted at iC j the coPPer works consumed about 200,000 le tm works about 150,000 tons the shipments irom different ports were—from Newport, 600,000 tons; from Cardilf 550.000 tuns; from Neath and Swansea, upwards of 500,000 tons; and from Llanelly, 100.000 tons; agricultural and domestic purposes consumed 750,000 tons, forming an exhausting process of about •.«J50,000 tons per year. If, then, tliey took the area of coal available for exhaustion at only 100 square miles, and estimated the amount to be obtMned at only the trl. ftittg quantity of 61 millions of tons, the supply would meet the demand at the present rate of consumption for 1409 years to come. Lord Northampton hoped Mr. Boker would, on Mon- attend the Statistical Section, and communicate to them tbe valuable d lta be bad that morning laid before this Section. SECTION D.-ZOOLOGY AND BOTANY. 44 (Sr;,Th2mas ^ams' M.D., of Swansea, read a paper „r.e structure and Functions ot the Branchial Organs tne Annalidoe and Crustacea." Professor Owen read a paper On the development and I • j be teeth in the Kangaroos; and on the homo- au,»noVnon ot lh.e tee,h in Mamalia." Likewise a paper On the eustachian tubes in the crocodiles." ,wei^ "On a peculiarity in Protococcus fl '.8' ,byJW- Moggridge, Esq.; "On vegetable mon- ••Mtties, by E. Lancaster, Esq., M.D., F.R.S.; and Esq 00 development of Pollen," by A. Henfrey, SECTION F.-STATtsTtCF. By Joseph Fletcher, barrister-at-Iaw—M Statistics of Srttany and the Bretons." By Col. Sykes, V.R.P.S. Statistics of the legal affairs of the Government of Bengal." Statistic&eSa0r e"—" Cwtfributions to Academical SECTION G.—MECHANICAL SCIENCE. « at tl,is Sect«o«» were by Mr. J. Glynn, .J1?". Pressure engines." Bv Mr. F. Wishaw, un the V elocentimeter, with its applications." The lecturer produced numerous specimens of gutta percha in t raape.of thread, cord pipes, bands, constable's staves, Sticks, vlnna ink«.L i • i i r -.—, ineuaiuons, snieias, water buckets, Mercotype plate, and almost every thing. He explained Ae nature of gutta pemha-the concrete juice of a large tree in Borneo, obtained by the Meiays. Its introduction onto this country was purely accidental- Dr. Montgomery having transmitted the first specimen to the Society of 'ritS c" to which Mr. Wishaw himself was secretary. I he first articles made of it were shown in 1844, consisting I a, atbem band, a short pipe, and a bottle case, which he had made by his own nand, having softened the sub- stance by immersion in hot water. Cast iron medals and surgical instruments also shewn at the time attracted much attention. I t was also adopted for commercial uses, and trom that petiod till July, 1848, nearly 700 tons had been imported for the Gutta Percha Company. Mr. Kene, cBemet to-the company, had shewn that it was not a sim- ple ear bo-hydrogenous substance, but in its ordinary state there were at teast in it distinct materials besides a metallic proportion of sulphur. Under the influence of heat and pressure, gutta percha would spread to a certain extent, especially if mixed with foreign substances. In its pure state, gutta pereha was an excellent non-conductor of electricity. Mr. J. Scott Russell then proceeded with the improve- ments which had been made in Steam Navigation, which ■«e explained by appropriate diagrams. The tint great improvement that had been made was in the boilers. For- merly the boiler flues were constructed of great length, so "tiist the STioke was kept winding round and round in the Hues, and at last was allowed to escape with diffi.culty. Now, however, they had adopted the plan of getting as much fire as possible in the shortest space of time, and this had been accomplished by imitating as nearly as they could the locomotive engine boiler, by having tubes of thin metal, which would evaporate a ranch greater quantity of •water in the same time as flues of the u*u*l thickness; now also, instead of taking the smoke a long dance as in the old fashion, they used short flues of four to six feet in length, and by having a great many of as thin metal as possible they heated the greatest quantity of water, and had the additional advantage of keeping the metal cool; in consequence of which, a boiler of smaller extent and surface was of much greater efficiency, with less weight of metal. The next point of improvement was in the engine, in the construction of which, however, there had been less change than in other matters. The former Beon engine had been changed for the direct erection engine, which was of vario«i« kinds; but the greatest change which had Yn mad? within thela«t ten years consisted in the em- ployment of greater quantifies of wrought iron in the con- struction of the engines, instead of the mass of cast iron .i""u L wa* the °'jy chaiige for tne Halifax steamers, fitted up with the old fashioned lever enziotea. It was only within the last ten years that tbey had adopted this principle, the effect of was, that instead of coiaplrtcly filling the cylinder with stc.sm, they tilled it emly to the ctten t .;f one-tourth, 411.1 oiitainei*. ¡ a volune of steam, not of course of equal density, but by which they got two-thirds of the work done, and at one-fourth ttoe cost. The next iinprnve- ment had been made in paddles, not so much perhaps in the wheel itself, for lie was still inclined in favour ot the P^d«il«»-wl»eil, although tor short voyages he admitted advantage of the feather paddle which had been advo- eated by Mr. Price at their meeting som-years ago, and 4w bad then opposed him, but of this by .ittd.tiyf, the fcreat improvement which 'lid been made being the driving the paddle-vhcels tiistff. They had an old maxim, and a most important one, which was, whereas a good old horse going 21 miles all hour could not draw more than 200 tf-t P* r m)n"tf. and that as of, <'e'n) fngine was only a sub stitu'e or ho and rr ckoned as so Hi ich horse power, it t>ij|:ht not go a ser than 'IK miles per Iwur.. and this on* Wing had kept them hack fur half a century. "Me did not Wein that the result should be faster th .n 21 miles per ""ur» th it the pistcn s iou!d nut rise u.> .mil down ;n !jl '^er taster than "2J mites an 1 o ••, w Heii was only in a second, while the motion ot steam was l:tOu •<t iii a sccoiid. Fortuna'fl)-, however, i^is old nvixm oeenatyaiidQ led, «nd (lie pi-'on now mo^ed from 2 •»'). « k!"ri el lu,nute; an'' he k'-ew no reason why 8 u'(' 'V" attain the r.tte ot .*> • ;>r tins iuiprovemrrt Hey wer„- md bted to no new pau^i|>lt-, but to the i| ptu a tion of mathematical principles of science. He now cime to another great improvement, which WHS the change in the formation of which had been ra(iical; he meant the entire alteration in the form "f ships. A fe.v vears ago steam vessel which would go 10 or 12 miles an liour were deemed fltst ships now, however we had at- tained a much higher rate ot speed. Vessels were then built on the old fashioned piinciple that the water line should be nearly straight, and that the run of the vessel should be a line. and that there should never be a hollow line, except a little in the run of the ship, but that there most certainly should not be any hollow line in the bow, for there it should be straight or a little convex. Re- searches and inquiries were, however, made by a Com- mittee of the British Association as to the form of bow which would enable the vessel to go fastest through the water. These inquiries lasted for years, and they es- I tablished, by a series of experiments, a set of very curious facts. Formerly, every builder of ships had his notio.. of proportion, viz., that the length should be four times the I breadth; others, that it should be 41 or 5, and some went so far as to say that the length should be six times the breadth, but these were deemed innovations; so that, al- though the proportions of width as compared with breadth were said to be fixed ones, yet strarigley enoucr:; every one differed as to those proportions. Another question was, what part of the vessel should have the greatest width, and it was generally thought that the greatest width should be nearest the bow. Some daring persons had. however, put it back as far as the centre ot the ship. This was, how- ever, the exception, and not the rule. Then there was another great principle, which was, that the bow and stern should balance each other, that is, that the ves- sel should be equally balanced; but the new rules which the British Association had established were as fol- lows :-Tlu-y began by upsetting the old rule with respect to the proportions which the length should bear to the breadth, and showed that the greater the speed required the greater should be the length, and that the vessel snould be built merely of the breadth necessary to enable the engines to be put in, and to stow the requisite cargo. Then the second great improvement made bv them was, that the greatest width of water line, instead of being befere the middle, should be abaft the middle of the vessel, and in fact, two-fifths from the stern and three-fifths from the bow. The next great improvement was, that instead of having the bow broad and bluff, or a cod's head bow, for the purpose of rising over the wave, that you might leave hollow water lines, or what were called wave lines from their particular form. and with that form the vessel would be propelled with less power and greater velocity and also that instead of keeping to the old line run abaft and cutting it away, you might with great advantage have a bluff line abaft, provided it was fine near the water. Thus by these improvements the form of the old vessel was pretty nearly reversed, to the great annoyance of the old school; by which plan the steamers were givpn large and commodious cabins and after-holds, instead of having cabins so pinched in that you could hardly stand in them. Another heresy, introduced by the British Assocition, was, that the principle as to the balance of the stern and the bow, upon which they now rested, was founded in a most singular, error; they left out something which was very material; they concluded that the wave acted equally on both ends of the vessel in striking it, but they did not take into consideration the impossibility of this, not having taken into calculation the velocity of the wave or of the vessel, and that from this circumstance the concussion from a wave stricking the bow would be a most powerful one, while it could not be so within the stern because, if the velocity or the wave meeting it was fifteen miles, the shock would be as of thirty miles; and, therefore, it be- came most plain that the bow should give the least resis- tance to the wave. He had examined all the fastest steamers which had accomplished fifteen to seventeen miles an hour—and in smooth water eighteen miles an hour-and he would venture to state that there was not one of them which accomplished from fifteen to seventeen miles an hour which had not all these alterations in every particular, and that the wave form and wave principle was now adopted by all the great steam-ship builders, and that all the fast steam-boats had what was called the wave bow. Now, of the eight boats on the Holyhead and Dublin sta- tions, if examined, it would be found that all were built on these principles, although in some of them there was still left a little of the old principle, some of the boats being made a little thicker and more straight; and if any one would look at one of these boats, it would be perceived that the moment they moved the very wave itself rebelled against them, dashed against their bows, and that conse- quently they were slower than any of the others. Mr. Joseph Price said that as his name had been men- tioned, he rose to say that he agreed with Mr. Russell in all that he had adduced. He rose, as it might be said, to endorse his bills. There was, however, one mode of steam navigation—one mode of propulsion to which he had not alluded, he meant the mode of propulsion by the screw pro- peller. He would, therefore, mention that they had built a little vessel called the Neath Abbey, which plied from Neath to Bristol, a distance of upwards of sixty miles, and which had only 2-12 inch cylinders-in fact a mere toy, of course using high steam. Now she could walk round the Hereford, which had two forty horse-power engines— the working her upon the high pressure steam principle necessarily increased the speed of the piston—with these engines they had stepped out of the old track. They had not adopted the American plan of a high pressure engine and piffing of the steam, but of a high pressure engine without piffing of the steam, and without using a drop of cold water. He confessed that when this plan was pro- posed by his younger coadjutors, he, as one of the old fashioned, hesitated, but at length consented. The Neath Abliey had a screw-propeller with three blades, which were immersed under the water—her propeller being about 31 feet in diameter. The vessel is built in the best form, allowing sufficient breadth for her engines. The 2-12 inch cylinders are placed diagonally, and slung up by wrought iron beams, and they lay hold of one crank pin like the hands ot two men working at a grind-stone. Mr. Price made several additional apposite observations on the sub- ject. Mr. J. C. Dennis read an interesting paper on the re- flecting circle, more particularly in reference to an instru- ment for the purpose of measuring regular distances and so great is the accuracy required in instruments of this kind, that it is necessary to distinguish to the 5940th part of an inch. The smallest error of construction, therefore, produces a serious error in the observation and to render the construction more perfect, the following suggestion is made:—Instead of attaching the circle (technically called an arc) to the parts which support it, let the whole be cast in one piece, and then placed, polised or divided, to suit the purposes of modern astronomy. At four o'clock, the Ordinary took place at the Assembly Rooms, which was attended by about 100 gentlemen. On this occasion, the chair was taken by Sir Henry Dc la Beche, and the vice-chair by Starling Benson, Esq. From the Ordinary, the members repaired to Singleton, the seat of our esteemed J. H. Vivian, Esq., M.P., to witness Lieut. Carte's rocket experiments, which were seen to great advantage in front of the house, and produced a thrilling effect amidst the trees. SATURDAY. On this day the weather was tolerably fine, which enabled parties to make, according to arrangement, excursions to the various attractive localities in the neigh- bourhood and visit the extenoive manufactories of the place. The works and manufactories accessible and gra- tuitously opened for the members on the occasion were— The Potteries of Messrs. Dillwyn and Co. The Copper Ore Yards on the Banks of Swansea River. The Warlick Patent Fuel Company (by special order)." r The Hafod Copper Works and Rolling Mills of Messrs. Vivian and Sons. The Middle Bank Copper Works and Spelter Rolline Mills of Messrs. Greenfel. The Chemical Works of Messrs. James and Son. The Zinc Works of Messrs. Vivian and Sons. The Colleries of the Swansea Coal Company. The Tin Works of Messrs. Parsons. The Ystalyfera Iron Works; J. P. Budd, Esq. The Anthracite Colleries of Abercrave and Cwm Twrch. The Yniscedwin Iron works of P. M. Crane, Esq.; and The Briton Ferry Iron Rolling Mills. The places selected for the excursions were up the Swansea Valley; Cerrig Cenen Castle; the ValeofTawe; the Caves and Waterfalls of Llan-yr-Ogof, in the limestone hill of Cribbath; the Waterfdt of Ischoed-yr-Henrhyd; the Lamb and Flajt, and the Caves and Cliffs of Gower Singleton Abbey, and Penellergare. ELECTRICITY A MOTIVK POWER FOR VESSBLS.—One of the most interesting of the excursions was that to Penel- lergare, the mansion of J. D. Llewellyn, Esq., about five miles from Swansea. The boat, which was impelled by the electrical current, was the principal object of attrac- tion. It was not constructed for the purpose, but was the boat ordinarily used on the lake for pleasure ^purposes, capable of conveying six persons, and the construction of which is due to J. D. Llewellyn, Esq. (the host of this scientific party), and to our talented countryman Mr. B. Hill. A reference to a similar attempt made some years since in a far distant country (Russia), may prove not un- acceptable to such of our readers as feel an interest in the history of scientific pursuits—in watching the successive steps by which men's minds progress in the cause of im- provement :— In 1838 Professor Jacobi of St. Petersburg, at the ex- pense of an imperial commission, tried the grand experi- ment of propelling a boat by the agency of electro-mag- netism. The vessel was a ten oared shallop, equipped with paddle-wheels, to which rotary motion was given by means of an electro-magnetic engine. The boat was 24 feet long by seven and a half feet beam, and drew two or three-quarters feet of water. In general there were 12 or 14 persons on board. The voyage on the Neva was con- tinued during entire days. The then difficulty of managing the batteries and the imperfect construction of the engine were sources of frequent interruption, and could not be well remedied on the spot After these difficulties were in some degree removed, the Professor gives us the result of his experience, that a battery of 20 square feet of surface of platinum, five will produce a power equivalent to one steam horse power; he hoped, however, to be able to ob- tain the same amount of power with half the amount of battery power (a surface). The vessel went at the rate of four miletl per hour, which is certainly more than was done by the first" little boat propelled by steam. In 1839 Jacobi tried another experiment in the same boat, the engine being the same, and which occupied but little space; it was worked by a battery of fit pairs ot pla- tinum plates, each having 36 square inches of surface (this battery, it must be observed, being only one-fifth the size of the one previously employed in the experiments of 1838), and was charged, according to Professor Grove's plan, with concentrated nitric and sulphuric acids. The boat attained an average speed of three miles per hour, with some 12 or 13 persons on board.- The following is a description of the electro-motive power used at Penellegern. It consists of a stationary electro-magnet of a rectangular form, the ends of which are about ten inches apart. Around this magner there are coiled about 800 yards of covered copper wire (No. 15 guage) in one continuous coil. The ends of this wire are in connection W:t'1 Grove's battery of eight platina ptate* Nith double zincs, each platina being about six tnehes square, or exposing altogether eight square feet of platina in the w'io!e battery. The rotating magnet is made of two pieces of soft iron '■velded in the middle (each piece being ten inches in length), so as to form four radii or arms, around each of which wi re coiled 50 yards of covered copper wire, which terminated in two circles ot copper, each circle being inslI- hited fr.itti the othf-r. and divided into two equ.il parts. These circles are acted upon by two springs connected with the battery above referred to; the division in con- nection with the rotating being at such a point that the division and the pole of the rotating maiwrt shall coincide with the p-<le of the stationary magnet; inasmuch as inng- lets ot the polarity epcl eaeh other, and magnets of a eintrary polarity attract each other, it is evdfnt that at ach revolution of the magnet the polarity is ehanyd, cou- equently a continuous rotary motion is ubtained. By i action i f the rotating magnet on a screw pro- peller, by moans of a cog wheel at,. ch. d to the axie ot the rotating m igr.et, and another who. I on the axle of the s;rew propeller, the boat was pllt in motion. This b, at -bl,- of carrying seven person. but on this o<casionj 3 ,.ot w Ire than five were in at one tim WiAa this carg ] the speed at which it was propejled was miles an h ui -a speed some of our readers may think not very great. but it must b? recollected that. the boat w is not constructed for fast sailing. The contrivance for recovering the motion and s'npping the same, is most complete, ^nd may thus be described A circle of copper is divided into eight equal parts, and placed at three quarters of an inch apart, each of which is in connection with the w;re coiled round the rotating magnet, and also with the poles of the battery. A piece of copper in the form of a cross, each end of which, when in contact with the first four pieces of copper, makes the magnet revolve (say trom riflit to left), hilt when in con- tact with the secondYour, the magnet revolves from left to right; and when the cross is in such a position as to be on the space between the above described eight pieces of cop- per, the magnet becomes stationary. The large body of visitors who witnessed this ingenious contrivance expressed the greatest satisfaction at the lestilt of this trial of electro-motive power. The first promenade and soiree took place on Saturday evening, and the last on Tuesday evening, at the National School Rooms, and we cannot but congratulate the mem- bers on their brilliant success on boili occasions. On Sunday morning the Bishop of St. David's preached in St. Mary's Church on behalf of the National Schools. MONDAY. SECTION A.—MATHEMATICAL AND PHYSICAL SCIENCE. Sir David Brewster said that he would confine himself to the physical and optical aspect of the subject. In so far as it had become a metaphysical question, it was out of the sphere of his own studies. After stating that he had been called upon officially to deliver a course of lectures on the philosophy ot the senses, he had been under the necessity of perusing, with some caie. Bishop Berkeley's ingenious essay, entitled "A new theory of vision." He had done so without being desirous to question the Bishop's result, or to criticise his speculation. The great object of the new theory of vision was to prove that distance is not seen di- rectly by the eye—that all objects appear in one plane- that even outness is not seen; and that it is by experience alone that we learn to see the form and distances of ex- ternal objects. These opinions, which have been consi- dered as demonstrated, have been adopted by the most distinguished philosophers of the last and present century, and lie (Sir David) was not aware that they had been called in question by any writer who had made the subject of vision his particular study. The fundamental proposi- tion on which the new theory of vision rested, according tp Dr. Berkeley, was, that distance was represented by a line stretching lengthwise from the eye but as the image of that line on the retina or bottom of the eye is a point distance, or the line which represents it, has no linear re- presentatition in the eye, or is not visible. He (Sir David Brewster) considered the proposition as not true. It was true when the section of the line was equal to or greater than the diameter of the pupil, or when the pupil of the eye is reduced to the^mallest possible dimensions. In the hu- man eye the line representing distance is distinctly repre- sented on the retina, and it is visible throughout the whole of its length. Sir David then referred to the figures on the demonstrating board as explanatory of his views. He proved that distance was represented by a line on the re- tina, when vision is performed by one eye; he had conse- quently disproved every proposition which Dr. Berkeley had founded on the opposite conclusion. He thought it was not easy to understand how Dr. Berkeley could have ventured to deduce general propositions regarding vision from a fact, which, if it were true, was true only when a single eye was used. Man was not an animal with one eye. Mankind were not the offspring of Polyphemus. The intant obtained its first glance of the visible world by opening upon it both its eyes. And in whatever school it was tsught, whatever were the lessons of experience which it learned, each eye must be considered to be equally pro- ficient in the knowledge which it received. He did not consider it of importance to consider how single vision was produced by two eyes. It might be from the images falling on corresponding points of the retina—a doctrine now ex- ploded. It might be from the decussation of the filaments of the optic nerves-a doctrine also exploded. Or it might be the necessary result of the line of visible direction, as certainly it was. But from whatever it arose, it was a fact which must be admitted. They had therefore to determine when, and at what distance, an object would be seen with two eyes when it was seen single. Sir David then adduced a number of facts in support of his views. It was admitted on all hands by naturalists, and even those who maintained the Berkeley theory, that the young animab saw distance at their birth. The duckling ran to the water as soon as it was extricated from the shell, and in like manner the boa constrictor would bite at and seize an object presented to it. He had never known or heard of an instance where an infant mistook a single object for two; but he had, on the contrary, had innumerable proofs of the fact that the infant had the knowledge of distance, and applied that knowledge practically when it wished to seize any object that it desired. He said, in conclusion, after citing several cases referred to by Bishop Berkely in support of his theory, after a minute and careful analysis of them all they Croved unequivocally that persons born blind, and who ave had their sight restored by the depression or extrac- tion of the crystalline lens, or by the formation of an arti- ficial pupil, see objects at different distances from the eye. He did not conceive them, as had been alleged, either to touch the eye or to be placed within it. Dr. Whewell, after expressing his sense of the value and ability of Sir David Brewster's remarks, considered the views he so ably enunciated were confirmatory of the theory of Bishop Berkeley, rather than undermining the old doc- trines. With reference to the vision of animals, he said that could not be adduced against the Berkeleyan theory, as it was an exhibition merely of instinct, of the value of which we know nothing. It might as well be said that children do not walk by experience and practice, because some animals run about from the moment of their birth. Dr. Whewell maintained that experience showed that children have little or no distance, for if they do not try to catch the sun or the moon, they frequently attempt to take hold of the flame of a distant candle. Mr. Esling also came in support of the Berkeleyan theory, with the case of a young man born blind, who, when couched, had no idea of the distance of objects; he put his hands to his eyes and preferred feeling for what he wanted, as he had been accustomed to do. Dr. Lee next communicated his further Meteorologi- cal observations at Altona, in Finland;" after which Col. Sykes read two extremely interesting papers; the first "On the fall of rain at Ultree Mill lay, Travancore, as observed by General Cullen;" and the second On at- mospheric disturbances, and a remarkable storm at Bom- bay." The gallant Colonel, in commencing, alluded to the extraordinary coincidence, during the last year, be- tween the political commotions in Europe and the very disturbed state of the atmosphere throughout the world; and Col. Sabine afterwards made the same observation in regard to the state of terrestrial magnetism. The thermo- metrical, barometrical, and magnetic records adduced by Col. Sykes were of a very remarkable character, not only shewing extraordinary vicissitudes, but also giving indica- tions the very opposite to those which, a priori, should have been expected; e.g., the magnet perfectly quiescent during a gale, but for5f. hours after its cessation, in a very disturbed state. Similar instances were adduced respect- ing the indication of the thermometer. Dr. Siljestrom, On the aurora borealis of Norway, in the winters of 1838 and 1839." The locality from whence Dr. Siljestrom had had the opportunity ofobserving the aurora may be said to be its home. This communication elicited remarks from Col. Sabine and Dr. Loyd, who both differed from Dr. Siljestrom in respect of his mode of cal- culating some of the indications of the magnetic needle. Dr. Loyd thinks that India is the country best calculated for affording data upon which to form a general magnetic law; and that we are now coming upon a magnetic crisis. The magnetic observations were commenced in 1839; therefore he thought it too soon to attempt to generalise. Papers "On the aurora at Swansea, in ] 844," and On meteorological observations at Swansea," followed by Mr. J. Jenkins. These meteorological observations would have been of value, had they afforded the means of ascertaining the mean temperature of the locality. Sir D. Brewster informed Mr. Jenkins how he should Droceed in future in making his observations, and suggested the de- sirableness ot taking the temperature of the spriugs of the neighbourhood about two or three times a month; and Dr. Lee said that Mr. Glazier, of London, had prepared tables, one of which he, Dr. Lee, then exhibited, in order that any one having a desire to register, might do so, properly; and that Mr. Glazier himself was ready to reduce such ob- servations, on their being sent to him. The last paper was one by Mr. Moggridge, On two cases of uncommon atmosphereic refraction." The first case occurred near Aberavon, when a schooner, situated considerably below the line of a direct vision, and which line was obstructed by a sand hill, was still completely seen. The second case was a reflection in the Mumble range of rocks, seen from Swansea. In both these cases the images were not inverted as such images are for the most part.—Professor Rogers mentioned that Lake Su- perior, in America, afforded frequent and most distinct instances of these mirages; and Sir David Brewster said that an hour's reading of Dr. Vincent's p"per in the third vol, of the Edin, Pllil. Transactions would put any one in possession ot all the most remarkable instances of mirage. Sir David thinks that some how or other the air for the time assumes the form of a huge lens, and thus produces these effects. SECTION B.—CHEMICAL SCIENCE WITH ITS AFPLI-! CATION TO AGRICULTURE AND THE ARTS. The first discourse this day was delivered by the Rev. Thomas Exley," On the laws of Chemical Combtnationsand the Volumes of Gaseous Bodies." Mr. Richard Phillipa, F.R.S., followed with a very elabo- rate paper, On some properties of Alumina." Mr. Phillips disproved the opinion that alumina assumes the chrystalised form of having been kept. Mr. W. S. Ward then re<d a paper, "On the Electro- motive Force; Dyanmic Effect and Resistance of various Voltaic Combinations." Professor Grove next brought before the Section his ex- periments and researches, On the peculiar cooling effects of Hydrogen and it Compounds in cases of Voltaic Ignition." Mr. Nasmyth read a paper on a peculiar property of coke hitherto undiscoverad, namely that it will cut glass like a diamond. The audience were much amused by seeing several pieces of glass cut with what was apparently a piece of ordinary coke. He also read a paper on the chemical properties or steel. A Glass Manufacturer observed, that, as they expended from iJ200 to £ 400 per annum in diamonds for cutting glass, they wcii'd gladly recognise any efficient substitute; but after a fair trial, it was found that roko could not answer the purpose. The last paper of interest was read by Ur. D»ubeny, being a report of the progress of his investigation On the influence of carbonic acid on the growth of ferns." Mt. W. It. Randall read a paper, On Common Salt as a Poison to Plants." SECTION C.—GEOLOGY Professor A. C. Ramsay proceeded with his discourse "On the submergence of ancIent land in Wales the accu- mulation of new strata around and about it; and the reap- pearance of the same land by denudation and elevation." Professor J.imes Buckman then read a paper on some experiments, and borings in search of coal. The object of this paper was to give an extract of two instances of boring for coals, which came under the author's own observation", and in both of which his geological were sought tor. The P esident remarked that the instance adduced by VIr. Bu.'kman added another to the many illustrations of persons fo ling aw iy large sums of money in boring for coa! in places where, as must be known by persons pos- sessing the slightest geological information, coal could not have existed. There was hat.ily a locality in which such] instances were not found. It was often the case in dis- tricts like Swansea, surrounded bv roal, that persons often b r d in places oul^ £ which, from the character of the stratification, coal p¥ not be obtained. j Dr. Buckland remarked, had Lord Northampton been present lie might have told them of a case in w'deh UD- •v;,rJs of £ 20,000 ba$lpee" co expended near Northamplo v

ISECTION D.—BOTANY, ZOOLOGY,…

A G R I C U L TURK, & c.

CUltRENi l'lilCES OF UllAIN…

SMITHFIELD MARKET.—MONDAY.…

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