steel. The author's leading experiments are not detailed in the present paper, but the results are thus stated: Mag. Pow. 100 hard These ratios were obtained by observations made on two bars of each specimen, 2 feet long and 1 inch square; and the results are therefore, we presume, to be considered as exhibiting not an accidental but the absolute magnetic powers of these different kinds of metal. Mr. B. remarks: As it was obvious from these experiments, that the softer the iron the greater was its power, and the contrary, I was desirous of determining how nearly these different kinds of metal would approximate towards each other in their magnetic action, when rendered perfectly soft by being heated in a furnace. With this view, bars of equal size of cast iron, malleable iron, shear steel, &c. were rendered white hot, and being placed in the direction of the dip, as before, their powers, as was anticipated, agreed nearly with each other; but still the cast iron, which was weakest while the metal was cold, exceeded a little in power all the others when hot, and the malleable iron which had the greatest power cold, had the least when hot; but the difference was not very great, and might probably arise from some accidental circumstance. While carrying on these experiments, it had been observed, both by Mr. Bonnycastle and myself, that between the white heat of the metal, when all magnetic action was lost, and the blood-red heat, at which it was the strongest, there was an intermediate state in which the iron attracted the needle the contrary way to what it did when it was cold, viz. if the bar and compass were so situated that the north end of the needle was drawn towards it when cold, the south end was attracted during the interval above alluded to, or while the iron was passing through the shades of colour denoted by the workman the bright red and red heat.' The latter very remarkable case was not likely to escape without farther inquiry; and Mr. Barlow, possessing peculiar facilities for such experiments in the magnificent smithery in Woolwich Dock-yard, proceeded to make the course of experiments which forms the principal object of his communication to the Royal Society *: whence it appears that the بسيط The entire series is given at large by the author in a new edition of his "Magnetic Attractions," just published: which work now embraces terrestrial and electro-magnetism. magnetic power of iron is not only much modified by the dif ferent degrees of heat to which it is raised, but that with certain shades of colour its action is altogether reversed. We will select one experiment by way of illustration. Bar-malleable iron-same dimensions as above, viz. length 2 feet and 1 inch square. Mr. Barlow gives the results of thirty similar experiments, from which no doubt can be entertained that iron at the red heat possesses a magnetic power directly the reverse of its natural action: so that, if the north end of the needle be attracted in any position while the bar is cold, the same bar in the same place, but rendered red hot, will attract the south end and repel the north; and, if made white hot, it will attract neither. This very curious fact will no doubt excite the attention of those philosophers who are at present engaged in magnetical pursuits, and will perhaps be found to throw great light on the nature and state of the magnetic fluids in iron bodies. Observations for ascertaining the Length of the Pendulum at Madras in the East Indies, Lat. 13° 4' 9".1 N., with Conclusions drawn from the same. By John Goldingham, Esq.-It has been for some time admitted that experiments on the lengths of the seconds pendulum form the best data for determining the true figure of the earth; and they have accordingly been much extended in late years, and in situations at which we had before but little prospect of arriving. The experiments on this subject by Captain Sabine, in the late Arctic expedition, are invaluable on this account; and the great uniformity of compression, arising from a comparison of that gentleman's observations with those that were made in England and other places, has given an additional importance to this inquiry, which renders the more acceptable any accurate course of observations of this kind made in distant parts of the globe. We have already, in different volumes of the Monthly Review, explained the principles now generally adopted in carrying this species of observation into effect, and, in the present instance, Mr. Goldingham has adopted the same proceedings in every respect. It will therefore be quite sufficient for our purpose to quote simply the results, and to express our unqualified approbation of the ingenuity, perse verance, verance, and accuracy with which the experiments have been conducted. It may be proper to state, for the purpose of illustrating the concluding remarks of the author, that the experiments were made in two distinct series: the first from the 24th of March to the 2d of April, and the second series from April 18th to the 23d. According to the former, the number of observed vibrations in twenty-four hours was 86166-108; according to the latter, 86166-048; and the number made in England by the same pendulum, before it was sent out, was 86293-14. These particulars being premised, the following deductions will be easily comprehended: The height of the pendulum above the level of the sea was 27 feet; the distance in a direct line to the sea being about 4900 yards, or 2,784 miles. The country is flat; the nearest elevation being St. Thomas's Mount, which is 9950 yards, or 5,654 miles off, and rises but little above the ordinary level. * There is a range of low hills a short distance beyond St. Thomas's Mount; and the Pulicat Mountains, which are of considerable elevation, are 39 miles off. The soil about Madras is composed of sand and blue mud, and this to as great depths as the wells have been sunk. - I do not recollect any rock having been found. I have therefore used 0,66 as a multiplier to 0,095, the correction for 27 feet, which gives 0,06 to be added to the number of beats in 24 hours. The last correction required was for the buoyancy of the atmosphere. Having no information relative to the specific gravity of the pendulum, I was obliged to determine it in the best way the limited means in this country afforded. This was done with a balance at a dispensary, and with the aid of Mr. Bruce, the proprietor of the establishment. The Madras water drawn from wells in the Black town here, and conducted into the cisterns in the fort, is considered among the purest in the world. This was boiled, and strained into a tin trough prepared for the purpose; the pendulum also was securely and properly slung by means of brass wire, with the assistance of Mr. Gordon, jeweller, of this place. The water was at the same temperature with the atmosphere, and the experiments were made with every care. It may be unnecessary to detail them here; I shall therefore proceed to the result, which was as follows: Thermometer 88°, barometer 30,064 inches, specific gravity of the pendulum 8,1085. Hence the specific gravity of the pendulum for the mean of the first series of observations, the thermometer being 830,48, and barometer 30,121, was 8,02096, and the correction for the buoyancy of the atmosphere is + 6,2075 vibrations. For the second series, the thermometer having been 85°,49, and barometer 30,258 inches, this correction is 6,220 vibrations. These corrections being applied to the number of vibra * About 150 feet above the level of the sea.' tions before found, will give the true number of vibrations of the pendulum in 24 hours in vacuo at the level of the sea, the thermometer being 70°, and are as follow: By the first series of observations, 86172,3755. By the second series, 86172,328. The mean being 86172,352. The length of the seconds pendulum in London, (latitude 51° 31′ 8′′,4 N.) at the temperature of 70°, according to Captain Kater, is 39,142213 inches. Now, the pendulum of experiment used at Madras, made 86293,44 vibrations in 24 hours in London, latitude as before, and 83 feet above the level of the sea, the mean height of the thermometer being 67°,6, of the barometer 29,97 inches. The correction for the height above the sea is 0,22, and that for the buoyancy of the atmosphere 6,566, both to be added: these corrections being applied, will give 86300,226 for the number of vibrations of the pendulum of experiment in 24 hours in vacuo at the level of the sea, the temperature being 70°. Now, 86300,2262: 864002: 39,142213: 39,232772 the length of the pendulum of experiment. Then 86172,3752 : 864002 :: 39,232772 : 39,026323087, the length of the seconds pendulum at Madras by the first series of observations. Also, 86172,3282: 864002:: 39,232772 : 39,026280447, the length of the seconds pendulum at Madras by the second series. The mean of both is 39,026302 inches, being, according to Sir George Shuckburgh's scale, the length of the seconds pendulum by these experiments at Madras in lat. 13° 4' 9",1 N. at the level of the sea, in vacuo, and at a temperature of 70° of Fahrenheit. Then comparing this length with 39,142213 inches, the length in latitude 51° 31' 8,4 N. as before stated, the diminution of gravity from the pole to the equator will be ,0052894, and the ellipticity 1 nearly.' 297,56 Communication of a curious Appearance lately observed upon the Moon. By the Rev. Fearon Fallows. This seems to us to be a very unimportant paper; for it merely states that, on a certain night at the Cape of Good Hope, a bright spot was observed on the disc of the moon: the exact place is not pointed out; nor is any indication of its position given in such a way as to enable us to judge of its particular situation. It would appear to have been discovered merely from the circumstance of the extreme brightness of the lunar disc; and an expectation is intimated that it might be observed again in another lunation. We think, then, that the author would have done well to have waited the event before he made his communication. ART. VIII. A Journey from Merut in India to London, through 19 Ir may 事 Boards. T may be premature to assert, but not premature to discuss, the practicability and expediency of instituting a regular conveyance over-land between London and Calcutta. During the continuance of the present peace, certain conventions might be made with the respective sovereigns of the intervening countries, in order to smooth the rugged tracts of road, guard the intervals exposed to robbers, and found the necessary inns of refreshment and relays of horses. There can be no difficulty in landing the passenger from a steam-packet at Ostend with sufficient punctuality, nor in sending him forwards with convenience to Vienna, and no great additional accommodation to provide for the purpose of reaching Odessa. Here, however, the obstacles would multiply travelling establishments and workmen are scanty along the Russian roads; and it would be necessary to proceed slower, or at least to make longer pauses, in order to 'allow for accidental detentions, and to depart from every imAs far as Bataiskaia, portant city at a given day and hour. the extreme city of Europe, a contractor would know how to realize his agreement. We may remark here, en passant, that Mr. Lumsden's text speaks of Bataiskaia as on the western bank of the Don, and that his map erroneously places it on the eastern or left bank. The quarantine-precautions usual at the Asiatic frontier do not delay the European who is journeying eastward, but are often productive of inconvenient stoppage to the Asiatic who is journeying westward. These precautions are unskilfully arranged in the Russian empire, and would require a revisal by negotiation, if any regular celerity of progress is to be observed. In Asia, the roads become harassingly bad, and on the Persian frontier dreadfully unsafe. A troop of pioneers, therefore, must be engaged to mend them, and to guard them but this is an expense which it would be worth the while of the Russian, Persian, and British sovereigns to concur in dividing. The roads, however, are as yet so bad in Persia, that Lieut. Lumsden informs us, (p. 85.) there are no wheeled carriages in the country.' Another route from Odessa to Bushire might be explored, by crossing the Euxine in a steam-boat to Trebizond, thence reaching by land the nearest bend of the Euphrates, (at Erzeram, perhaps,) and |