Skip to main content
Hide Articles List

4 articles on this Page

------_-----MEETINGS OF THE…


MEETINGS OF THE BRITISH ASSOCIATION. THURSDAY. All the sections met to-day at eleven o'clock, in their re- spective rooms. SECTION A.—MATHEMATICAL AND PHYSICAL SCIENCE, Assembled at the Girls' School, York-street. Lord Wrottesley in the chair. The Secretary, Dr. Steveley, announced that the paper of Robert Mallet, Esq., on the "Reports of Earthquakes and the Scisometer," was not prepared on account of Mr. Mal- let's health. He recommended that the subject should be left open another year, when he hoped his health would enable him to devote his attention to the subject. A Catalogue of Lumi- nous Meteors from September, 1833, to July, 1848," by Pro- fessor Powell, was then explained, but not read on account of the numerous tables which it contained. It comprised a brief notice of the meteors antecedent to that period, and very full details from that date upwards. Professor Powell has under- taken the work with the view of carrying it on from year to year. A hope was expressed that persons in different parts of the country would record their observations and communicate with the learned professor. The present paper contained many interesting letters and extracts from newspapers bearing on the subject. The next paper, Observations of the Annular Eclipse of October 9, 1847, was from the pen of Professor Powell. Great preparations had been made by astronomers to witness this interesting phenomenon, but unfortunately the wea- ther turned out unfavourable. A few peculiarities had been observed at Rome and Bombay which were enumerated in detail. Sir W. Snow Harris called attention to the paper of Profes- sor Powell on meteors, and made a few interesting remarks on its contents. He stated that a remarkable meteor had been witnessed and recorded in the Philosophical Transactions for the year 1789. It was that of several sailors, seeing what they imagined to be a large ball of fire, like a millstone, descending by their ship and which exploded in coming in contact with the water, after which great heat and a sulphurous smell were ob- served. This phenomenon, he had no doubt, was an electric cloud carried by the'current of air, and which exploded on be- coming pressed on the surface of the water. A similar ap- pearance also had lately been observed in Cornwall, (where a ball of blue sulphurous fire had been seen passing down the river within a few yards to a ship, and proceeding to the open sea at Penzance. A smell of sulphur and a great heat accom- panied this meteor likewise. The wind at the time was in the direction from which it proceeded, which left no doubt of its being an electric cloud. Another paper by Professor Powell On a new case of inter- ference of light," was read and briefly commented upon by Sir David Brewster. The Secretary read a paper from the same learned Professor on "An explanation of the 'beads' and 'threads' in annular eclipses." A paper by Mansfield Harrison, Esq., On a self-registering thermometer with twelve months' tracing of its work was read by the Secretary. The thermometer appears to be con- sstructed on the principle of metallic contraction by the force of heat and cold. Dr. Lloyd, of Dublin, seemed to think that the action would be irregular on account of sudden starts from the influence of the weather that might be expected in its workings. Mr. J. Jenkins, F.R.A.S., made a few remarks on the irregu- larity ot thermometers. He had been making several experi- ments, by hanging several thermometers on a garden wall some time before sunrise, and he had found that they had va- ried from a temperature of 60 to 60'a. Upon examining them however, at intervals of fifteen minutes, he found that these variations were irregular. He wished to know the reason of this. Dr. Lloyd supposed that the variations must have been occa- sioned by small currents of the atmosphere. He thought the proper way to make experiments of the kind would be the placing of thermometers in water, and so securing an uniformity Qr temperature. After a short conversation on the same subject between Mr. Jenkins and Dr. Lloyd, the Secretary read a paper on a 11 Re- markable tide in the British Channel, Friday, 7th July, 1848 as it appeared at Lyme Regis, Dorset, as collected by George Roberts, Esq., who was absent." Weather warm and calm; dead neap tides fine for twenty-four hours before the pheno- iúllJn. About, two hours and a half before the phenome- non, at one and a half, A.M., it blew hard for ten minutes. The wind before and after this gust was gentle and had gone round to all points of the compass. At dead low water or just after the water had begun to now, at 4 A.M., the tide beo-an to run into the Oobb, so that a boat rowed with two oars could hot make head against it, but was carried with it. My inform- ant estimates the height of the water to have been about seven ieet, and that it took eight minutes to flow in, or almost ten minutes, and the same time to flow out. Then when out it began to flow in again, and so continued till eight o'clock, a space uf four hours, when the sea was quite calm, and so con- tinued all the day. The same was experienced at Dartmouth and Portland. Some of the sailors said it was a bore others i..iat it was caused by thunder weather; some said there had been earthquake in the ocean. Some sailors say the tide ran ten knots an hour.—GEORGE ROBERTS.—July 19, 1848. After the reading of a paper by the Rev. Thos. Rankin, on the recurrence of the November atmospheric waves at Iluggate, from 1810 to 1818, the business of the section concluded. Scno=r B.—.CHEMICAL SCIENCE, INCLUDING/ITS APPLICATION TO AGKIGFRLTUITE AND WliE JTK.T3. President, Phillips, Esq., F.R.S. ATr. Robert Hunt read a paper entitled, "Report of Pro, gress on the action of carbonic acid on the growth of plants/" Mr. Hunt, in commencing his paper upon this important subject, said—This investigation was committed by the Asso- ciation to the charge of a committee, and two sets of experi- Lio-,its have been established—one bv Dr. Daubeny, in the botanic gardens at Oxford, and the other by Mr. Hunt, upon ferns which have been supplied from the Royal Botanical Gar- dens at Kew. The arrangements are such that two sets of these plants, belonging to the same class, are made to grow under precisely the same circumstances, except that one set is supplied with measured quantities of carbonic acid. Numerous preliminary experiments had to be made, and several sets of plants have been destroyed in the progress of these experiments. No general results can be announced beyond the fact that the plants, by being gradually inured to the agency of the carbonic acid, can be made to bear a larger quantity than when a large per centage is given to them at once. The experiments, how- ever, must be continued over a long period before we can arrive at any decided result. Upon the finish of the paper an animated conversation took place, it being considered most important in this neighbour- hood, where from the smoke of the different copper works there was so much disengaged carbonic acid that its effects upon the vegetable kingdom should be perfectly determined. The discussion ended by a recommendation that the experiments should be continued on a larger scale, and that a grant should be made for that purpose. The following papers were also read at this section:—Dr. Edward Schunk, Report on colouring mattersj" Mr. W. S. Ward on a new Galvanometer;" and Professor F. Saee, on the chemical and physiological phenomena exhibited in fowls fed on barley, communicated by Capt. Boscawen Ibbetson." SECTION C.—GEOLOGY AND PHYSICAL GEOGRAPHY. Sir Henry De la Beche in the chair. Papers were read in this section by Professor James Buckman, on the plants of Insect Limestone of the Lias formation and by the same gentleman on the "Discovery of some Lepiaceous Remains in the Lias of Gloucestershire which were followed with a paper by Capt, Ibbetson, LL.B., On the position of Chloritic Marl or Phos- phate of Lime bed in the Isle of Wight." A very interesting discussion followed, in which Professors Owen and Phillips, and Mr. Hutton took part. Professor Oldham read a paper by Evan Hopkins, Esq., C.E., On the polarity of cleavage planes, and their influence on metalliferous deposits." '.L iie paper was drawn up in a very complicated form, and exhibited much research on" the subject. Professor Ramsay and Professor Oldham, however, differed en- tirely from its conclusions, and entered into very able explana- tions to show that in many instances Mr. Hopkins had en- tirely mistaken the direction of the angle of cleavage, as it was frequently found from east to west, and not from north-west to east, as stated by him. William Price Struve, Esq., C.E., of Swansea, then read the following paper on THE GREAT ANTICLINAL LINE OF THE MINERAL BASIN OF SOUTH WALES, FROM NEWBRIDGE, IN THE TAFP VALLEY, TO CEFN BITYN, IN GOWER. The object of the few observations which I have to offer on this subject, is to describe the great central uprise of the coal measures iii Glamorganshire, between the Yale of Taff and the estuary of the Burry, in Carmarthen Bay. In doing so, I will at the same time mention some of the govern- ing features of the South Wales coal-field, confining myself princi- pally to that portion of it situated between the Taif Valley and Carmarthen Bay. This district comprises Glamorganshire and portions of the counties of Carmarthen and Brecon, and occupies an area of about 5.30 square miles. It is intersected by six principal valleys, down which the mineral produce is conveyed byeanal or railway to the several ports of Cardiff, Porfchcawl, Port Talbot, Neath, Swansea, and Llanelly. In order that the remarks which I have to offer may be brief and intelligible, I have prepared, from my own notes and the informa- tion supplied by the Geological Survey, seven sectional representa- tions of the coal-field in the district alluded to, and shall at once refer to them for a description of the stratification. The base of our coal measures is carboniferous limestone, which, it will be observed, is basin-shaped, having a general rise from its centre towards the north and south, to which all the coal measures conform; and they may be described as consisting of the following convenient divisions:- Ft. In. In. Ft. Black Mine; Band, Coal. First. The farewell rock or Millstone grit, containing no coal, and averaging a thickness of 400 Secondly. Argillaceous and arenaceous shales, with some beds of sandstones 360 36 — Thirdly. Strata of a similar nature, containing several seams of coal, some of which are very thick, and associated with mine, and are extensively worked at ail the iron-works 540 12 — 43 Fourthly. A similar stratification, but with some thick beds of quartz rocks, called the Coclsshuts, particularly well seen along the anticlinal line between Cwm Avon and Maesteg, and regarded by the miner as sure guides to some of the accompanying rich coal beds 420 12 3 Fifthly. Arenaceous and argillaceous shales, with occasional beds of sandstones and containing black bands, worked ex- tensively at Cwm Avon and Maesteg, and lately discovered at the Ystalyfera Iron- Works 540 — 18t036 11 Sixthly. A great accumulation of sand- stones, called the Pennant rock, inter- mixed occasionally with some argillace- ous shale, represented in this neighbour- hood by the Kilvey and Town Hills, measuring in thickness 3000 7 Seventh and last division, containing shales and some thick masses of sand- as stone, and measuring about 3000 37 Making a total average thickness of 8,230 60 36 ill In this statement I have only included the workable seams of coal and mine, my object being to convey a correct impression as to the available portion of the South Wales coal-field and in order that the geological arrangement of these divisions may be easily under- stood, I have distinguished them on the sections by various shades of colour. [The section was here explained.] An important governing feature of the coal-field is the Pennant rock its out-crop being nearly as well marked as that of the car- boniferous limestone. It may bo traced in nearly its whole thick- ness from Swansea to Carmarthen Bay, on the west, and eastward toward Briton-Ferry, Margam, Llantrissent, round by Pontypool, back to Merthyr, and across the tops of the valleys to Pembrey,' where it again disappears under Carmarthen Bay, On inspecting the section No. 1, from Hirwainto Llantrissent, it will be observed that the lower portion only of this deposit caps the hills about the Rhondda,and that it then bends oyer towards Liaiitris- sant, accumulating the whole of its thickness, and bringing in the Dyhewydd seams, which may be considered equivalent to Hughes's seam, near Swansea, or to the commencement of the highest divi- sion of our coal-field. The denudation from the Rhondda of this thick deposit of sandstone removes, as it were, an impermeable cover, which, in other portions of the district where it is found to prevail in its full thickness, must serve as a seal to shut out for ever from the uses of man the lower thick beds of coal and mine so extensively worked along the margin of the. coal-hold whereas in this locality, they lie within an attainable depth for mining, and as flat as can 1)3 desired by the minor. The next section, numbered 2, crosses Llangeinor raouiitaiii here the Pennant rock accumulates considerably. It is, however broken through at Maesteg, which lies one mile to the west, by the central uprise of the coal measures the lower divisions of which are brought up to the surface, and worked extensively for the supply of three large iron-works. As we proceed more to the west- ward, and approach the eastern confines of the Swansea Bay, the Pennant rock becomes more extensively broken through, so that the whole of the lower measures are brought to view, and workings of a most extensive kind have been opened upon them for the supply of a large iron-works, rolling mills, tin-plate mills, and copper- works. On inspecting section No, 3, it will be observed that the Pennant rock stands on the north and south side of Cwm, Avon, and that the lower measures must necessarily pass under Margam mountain, and crop out towards the sea. III conformity with this theory, pits are now being sunk in the neighbourhood of Port Talbot. The next section to which I shall refer is No.5, from Caswell Bay, in Gower, to the Great Mountain, in Carmarthenshire, con- structed by Mr. Logan and myself, and published in the Geological Survey. It will now be observed that the-uprise has completely removed the continuation of the southern portion of the coal-field which exists between Margam and Lkintrissant, and the limestone only is to be seen torn up and contorted in the manner described in the section. Proceeding still more westward through Gower, the limestone is found completely broken up, and the old red sandstone protrudes through from beneath, which is illustrated in section No. 6, constructed by Mr. Logan, and which shows a small portion of the lower shales reposing on the limestone at the western side of Oxwicli Bay. Section No. 4, also constructed by Mr. Logan, frora Port Ten- nant to Castle Cerrig Cennen, is introduced for the purpose of illus- trating, by an addition which I have made to the section, the pro- bable partial removal of the coal-measures under the Swansea Bay. It would appear, therefore, that the great central uprise of our coal-field, which has served so usefully to bring up the lower shales in various portions of it, is merely a continuation of what has actcd with so much more violence in Gower; and that this movement may perhaps be traced back into Pembrokeshire, where, from the evidence afforded by Sir Henry De la Beche's valuable surveys it appears that a gro it disturbance in the limestone and old red sand- stone has also takm place. I shall now close these remarks by some general observations. The annexed sections describe, with sufficient accuracy for general purposes, the governing features of the South Wales coal-field; vil-xicli, from the description I have given, has been shown to con- tain enormous mineral wealth. Section No. 1, for instance, ex- hibits 57 feet thick of workable coal; 60 inches of workable argil, laceous mine and from 18 to 36 inches of Black Band, all within an attainable depth, averaging a distance by the Taff Vale railway L, y of about 20 milc8.from the port qf Cardiff. One square mile of such a coal-field ought to produce, according to ordinary calculations, 4O,OQO;OO0 tons of coal, 8,000,(100 tons of mino, and 3,000,000 tons of Black Band. The Swansea section contains the coal-measures above the Pen- nant rock, which may be estimated at 25,000,000 tons of coal per square mile; and to this may be added the last estimate for the ooal and mine below the Pennant, which is available for many square miles at the tops of the valleys, where they are found tocrop out in proximity with the limestone, and on which all the great iron- works of South Wales are established. The extent of coal-field, therefore, which may be considered available chiefly to the ports of Swansea and Cardiff, may be esti- mated at about 400 square miles. The South Wales Railway will pass at the foot of all the valleys, so that on its completion the whole extent of this country will be in a condition, with the aid of short branches, to send its produce to either of these ports. As regards the qualities of the coals, they may be classed in the following order :—Bituminous coal, free burning coal, culm, an- thracite culm, anthracite for all of which there is an extensive con- sumption. The boundaries of these various qualities I have endea- voured to sketch out on the annexed sections. The bituminous and free burning coal appear to occupy the largest portion of the coal-field, and the anthracite and anthracitie culm the least. The anthracite commences slightly at Hirwain, and increases as it advances into Carmarthenshire and in Pem- brokeshire the whole of the coal-field partakes of that quality. The other qualities take a similar direction, and gradually and imper- ceptibly pass into each other till they become bituminous coals on the south side of the coal-field. The paper was illustrated by reference to sectional maps of the district, which had been very ably prepared by Mr. Struve. Dr. Buckland, Dean of Westminster, highly commended the paper, and dwelt at considerable length on the vast advantages that would follow to science and the economic arts from the experience of such men as Mr. Struve. In reply to questions from J. T. Price, Esq., Neath Abbey, and Sir 1. J. Guest, Mr. Struve entered into several explana- tions of his paper, contending that it was highly probable that posterity would work such parts of the mineral basin as were now thought too deep to be worked. He saw no engineering difficulties in the way of having pits of a mile or a mile and a half in depth. It was all a question of money. After referring to Owen, the first historian of the South Wales coal field in the time of Queen Elizabeth, and commend- ing the work of Dr. Buckland and Dr. Connybeare, Sir Henry De la Beche highly eulogised the paper just read, and the sec- tion adjourned till Friday. SECTION D.—NATURAL HISTORY. Several papers were read in this section among others there was one on the recent species of odostomia, a genus of gastro- podous mollusks, inhabiting the seas of Great Britain and Ire- land, by J. G. Jeffreys, F.R.S., L.S. The author, after a few preliminary remarks, gave an histo- rical account of the genus, and proposed the coalition of all the species now composing the separate genera of odostomia, the- muitzia, and eulimella, in one genus, treating the others as sub- genera and he founded this view upon his observations of the animals, as well as on the shells, of each of those so-called ge- nera. After describing the characters and habits of these mollusks he gave a synoptical view of the species, thirty-two in number. Of these, nine—viz., onotata, dubia, acuta, dia- phana, dolioliformis, fcnestrata, clathrata, and formosa,—he described for the first time. The author then proceeded in his notes on the different species to an elucidation of their syno- nyms, which was previously in a state of great confusion; and the following is the result of his researches :—Out of the thirty- two species enumerated and described by him, nine were new and hitherto unpublished; nine had been described and figured by Philippi as Sicilian shells one by Reelug as French ten by Loder as inhabiting the Scandinavian coasts seven by Searles Wood as crag fossils; and one (for which the author proposed to restore the Linnean name of lactea for elen-antis- sirna) as indigenous to the middle and south of Europe. ° Dr. Thomas Williams read a paper on the structure and for- mation of the bronchial organs of the annelida and crustacea. The author for introduction remarked that he had subjected the ciliary variety of epethelum in nearly all classes of inverte- brate animals to careful microscopic examination, with a view to determine the variation of structure, conformation, and size which these inanimate elements of organisation undergo in the i 10 lowest grade of the zoological scale. The general physiologi- cal law was then announced; that tenacity of life muscles of vertebrate animals exemplified especially by the deep sea mollusea, bore uniformly an inverse proportion to the quantity or amount of the respiratory process, for those classes whose habitations lie remote from the surface of the sea, and therefore from the sun and the atmosphere, vibritile cilia re- place a circulatory blood system as an instrument of breathing. Dr. W. described the cilia as angular points which mechani- cally separate the oxygen in solution in water, aided by the at- traction subsisting between the solid acute point and gases dissolved in fluids; and that the oxygen thus disentangled from the surrounding water afforded by its stimulating pro- perties the cell supporting the cilia, and sustained in constant vibritile motion. He would therefore venture to explain the phenomena of ciliary vibration, by regarding them as the re- Z" suit of the unmixed agency of unmixed oxygen upon the epi- z;1 thalium, the organic processes in these organismie being vigo- rous and active in the proportion in which they were exposed to the direct influence of the atmosphere. The author stated that he had arrived at the following conclusions after an ex- tended investigation into the characters of vibritile epithelia in invertebrate animals. 1. That cliiary epithelium is not universally present on the breathing organs of invertebrtea animals. 2. That as far as his researches into the subject have ex- tended, no anatomical conditions can be accurately defined as co-existing with and indicative of the presence of ciliated epe- thelium on the bronchial organs. 3. That the principle is invariably observed except only in those examples in which the respiratory organs are not ex- pressly localised, of reducing in every practical manner the thickness of all structures, and, therefore, that of the stratum intervening between the external air and the circulating fluids, and that this principle necessarily involves the flilttening of the true bronchial and pulmonary epithelial cells. '4. That comparative anatomy establishes the fact that the invertebrate animals, the figure of the mucliated cells, is not z, distinctive of the several structures of the organisation, and that the oval form of cell, which is the predominant variety in molluscous animals, is the product merely of mechanical forces acting from the interior and caused by the accumulation of the fluid contents, and is significant of an inferior degree of forma- tive power and that the prismatic order of cells common on the mucous structures of vertebrate animals by the preserva- tion of their own peculiar figure are denotive of a higher grade of organised energy. 5. That in consequence of the immediate agency of atmo- spheric oxygen upon the contents of superficial E., under which class the ciliated order was of course comprehended, no consti- tuents could accumulate in the chambers of the cells, and that with reference to the vibritile E. the glandular character of the cell as indicated by the presence of molecules and oily parti- cles, was sacrificed to the development of its motive appen- dages. 6. That some of the internal surface of the lungs of air breathing vertebrate are lined by a layer of mucus more or less dense, the oxygen of the air in passing into the blood is fluid- ified by solution in the mucus, or if the idea of gaseous signifi- cation be disallowed, dissolved before the penetration of the vascular parietes, it follows in every essential respect that a pulmonated air-breathing animal presents no exception to the general physical laws which govern the prowess of aquatic respiration. 7. That the presence of ciliary vibration, as proved by recent observation on the lungs of batrachian, ophidian, chelonian, and saurian reptiles, being air-breathing animaL, establishes the importance and probable necessity of motive epethelium as an clement of structure in the respiratory organs of all verte- brate animals, and that analogy strongly supports the belief that in the lungs of birds of mammalia ciliary vibration will be eventually discovered. The author then proceeded to a minute account of the vascu- lar system of the respiratory organs, of which it would be dif- ficult to present an adequate account without the assistance of a diagram. The blood system was reducible to three leading systems, in which the vessels piojected out from the cephalic or lateral portions of the body to a distance more or less consi- derable, after the bronchial iflaments or threads variously sub- divided. In these organs, Dr, W, maintained that contrary to the description of all systematic writers, the blood vessels con- sisted of an apparent channel in which the blood respectively flowed and returned, and that it did not consist of a single conduit in which a flux and reflux of the fluid had been sup- posed to occur. In the N'ereidse exemplifying the second type, the vessels were subdivided into a system of parallel capilla- ries, which enclose after the manner of a framework of the branchial mammiUary protuberances by the laetorial anne- lides 5 the respiratory and.recall were furnished with a system of rcteform, capillaries, ui pf the crustacea, third, the author grouped the respiratoiy organs, under the two principal divisions of external and inter- nal, which respectively again were distributed under a laiiie"- u lar and tubular order. The dense corneous integument of the Crustacea was described as investing in all cases the respiratory organs and intervening between the blood and the external mcchum. The motive appendages are ilabcHn, were described j as in all orders presenting a mechanical configuration, best adapting them to maintain in constant motion the branchire. This description was illustrated by beautiful preparations obtained from animals inhabiting the coasts near Swansea. SECTION G.—MECHANICAL SCIENCE. At the meeting of this section the first paper read was a very able one by Mr. (jlyn upon water-pressure engines, in which he described the method of applying water-power cheaply and efficiently where watcr-wlieels could not be used, by means of a pressure from above upon an engine working with pistons and Z, -S valves, and allowing of the gradual inlet and outlet of the water, so as to secure uninterrupted motion without any shock in the raising or depression of the piston. Mr. Glyn described one of these engines, which was equal to 168-horse power, and which had been working for years at a cost ofoniv £ 12 a year which was conclusive as to its utility, value, and power ;r ana the improvement in these engines was that the stroke of the piston, while working seven strokes a minute with a 200 foot fall of water, and an immense pressure, worked as gradually and as easily at the end as at the commencement of the stroke- the ingress and the egress of the water being so regulated as to prevent the shock or rush of the water, so dangerous hi- therto, and the motion is rendered as any mechanic can desire whilst at least 70 per cent. of the whole power employed is rendered available. Some persons had, however, tiloug-Tic ti, t these engines would be uncontrollable, which would be a ^reat them if it were so. This, however, was not the case, for he had seen the same engine working seven strokes per minute of a piston of 20-feet stroke, or 140 feet in a minute and had seen the same engine reduced to a single stroke in 40 minutes, so that it was evident that it was not only not un- controllable, but was adopted to a season of drought as well as to floods. The great importance of such engines in this mineral neigh- bourhood was then shown, and the reading of the paper g;tva great satisfaction. On the improved Velocentemeter, a paper by 1fr. Wishaw was then read as follows:- In 1839, when engaged in making a general survey of the railways of Great Britain and Ireland, I invented he first ve- locentemeter for the purpose of taking more readily than bv an ordinary watch furnished with a second hand the tinier occupied in passing over measured distances are usually marked by posts or standards at each quarter of a mile along a railway. The novelty and use of the first velocentemeter consisted first in the substitution of a central decimal hand for that of the ordinary second hand, whether placed centrally or excentrally- so that the time could be taken to the 100th part of a minute and, second, in surrounding the dial by an annular space conl taiuing the velocities tabulated from 12'60 miles per hour to 75 miles per hour—taking for a basis the fixed distance of a quar- ter of a mile. If the distances are in half miles, then half the tabulated velocity must be taken. In making a single observa- tion by this plan it was necessary to note the decimal division at the time of passing the first standard, and also the decimal division at the time of passing the next standard, and hanii)- subtracted one from the other to look at the table for the result By the improved velocentemeter, which has the addition of a moveable annular plate, on which the table of velocity is en- graved instead of on a fixed dial as by the first plan-a single experiment may be made by one observation. In passing the first quarter of a mile standard the centre hand is made to co- incide therewith, and also with zero (100) on the table, and when the next quarter of a mile is passed, the tabulated figures opposite to the central hand give the velocity required? If, however, a series of experiments are to be made, I take a book ruled with fov.r columns, having in the first distances in cuar- ters of a mile previously marked down next note down in the second column the minutes and decimals at the intersection of the central hand with each quarter of a mile standard in suc- cession then in the third column I place the differences ob- tained by subtracting the minutes and decimals given at each quarter of a mile's observation from those of the previous one and lastly, in the fourth column, the results are written down as obtained from the velocities already described. In addition to the noting down the velocities. for each quarter of a mile I regularly register the exact times of stopping and startino- at each station, S3 that the time absorbed by such stoppage is ascertained as well as the result of the actual travelling when the locomotive is at its full speed—a fifth column with tie gradients of the line marked down, and a sixth for observa- tions, &c., render the book complete. The instrument was then shown, and resembled a handsome watch; and it was stated that it had tabulated upward- of 1,000 miles without being out the 100th of a minute." Papers were also read on several other interesting subjects in this section. c. j