trembled to its foundation. The mass thus moved has been considerable."-Times, April 17th, 1857.

The following is the 'Times' account of one of the explosions at the siege of Sebastopol :

"Thursday, Aug. 30, 1855. The whole of the camp was shaken this morning at 1 o'clock by a prodigious explosion, which produced the effects of an earthquake. A deplorable accident had occurred to our gallant allies as they were pursuing their works with accustomed energy. A tumbrel, from which they were discharging powder into one of the magazines near the Mamelon, was struck by a shell from the Russian batteries, which burst as it crashed through the roof of the carriage, and ignited the cartridges within; the flames caught the powder in the magazine, and, with a hideous roar, 14,000 rounds of gunpowder rushed forth in a volcano of fire to the skies, shattering to atoms the magazine, the tumbrels, and all the surrounding works, and whirling from its centre in all directions over the face of the Mamelon and beyond it 150 officers and men. Masses of earth, gabions, stones, fragments of carriages, and heavy shot were hurled far into our works on the left of the French, and wounded several of our men. The light of the explosion was not great, but the roar and shock of the earth were very considerable. The heaviest sleepers awoke and rushed out of their tents. The weight of powder exploded was about seven tons, or 1400 rounds of 10lbs. each."-Times, Sept. 13, 1855.

The following is part of the French account of the expedition against Kertch

"

May 26th, 1855.-Finally, before evacuating Yenikale, they blew up a powder magazine, containing about 30,000 kilogrammes of powder: the shock was so great, that many houses were destroyed, and vessels anchored ten miles out at sea felt it severely." Moniteur' quoted by 'Times, June 1855.

And the following of the great explosion in the camp before Sebastopol, on the 15th of November 1855:

"Shortly after 3 o'clock on Thursday afternoon the whole camp, from Inkermann to far beyond Cathcart's Hill, was literally shaken throughout every square foot of its area, by the most tremendous explosion that has ever echoed through these Crimean hills. A greater quantity of gunpowder itself may have been exploded in some of the magazines discharged for the destruction of the buildings and works after the abandonment of the ruined city and fortress; but this is doubtful, and certainly there were never fired at the same time so great a number and variety of deadly and explosive projectiles. The force of the blow from the impelled air, the stunning noise, the flashing of the fire, the suffocating smoke, arrested every reasoning faculty, and took away all sense, save the instinctive impulse to fly from the source of evil. Among the regiments themselves of the light division, whether in tents or huts, a sudden sensation was felt as if of an upheaving of the ground, at the same time that a violent shock was experienced from the concussion of the air. Almost instantly followed the loud report of the explosion; not sounding as if a single charg or magazine had been fired, and without the ringing tone or decided character of a salvo of artillery; but seeming rather as if a number of magazines had been discharged, one after the other, so rapidly, that all the reports were blended into one. As the thunder of the first report subsided, its place was occupied by the sharp cracking sounds of shells bursting high in the air, the rush of fragments falling to the ground, and the loud bangs of shells which had been scattered and were exploding on all sides. Simultaneous with these, almost from the very commencement, was the crushing of wooden huts, splitting of timbers, and noise of falling glass from the broken windows. The tents were violently agitated, and sometimes the cords or poles were snapped asunder. Then followed a continued succession of minor reports, and the roar of flames, and crackling of burning wood, as the fire advanced and increased among the huts and artillery stores of the siege train dépôts. To say that it equalled in violence the combined salvos of a thousand parks of artillery might seem extravagant; and yet the simile would but feebly convey an idea of the volume of thundering sound that shook the earth for miles around, tearing down the most substantial masonry and wooden huts, and levelling tents as by the sweep of some invisible giant-arm. I had seen the explosions on and after the 8th of September, which so many pens have since described; but no half-dozen of them together would have equalled this one, either in force or sound. Over an area of nearly half a mile from the spot of its occurrence, the air was one huge column of powder smoke and cast-up earth, up into and athwart which ignited or exploding shells and rockets ever and anon darted and flashed by hundreds, spreading destruction to nearly everything animate and inanimate, within a radius of more than a thousand yards. Heavy siege guns were wrenched from their carriages and thrown many perches from where they had been standing, whilst the carriages themselves were torn asunder."-London Express, Nov. 29, 1855.

The following notices of the Great Blast at Seaford Cliff are extracted from 'Saunders's Newsletter' of September 15, 1856 :

"The great explosion at Seaford. There has been a great concourse of visitors in this little town today to witness the operation of 'blasting,' by the explosion of gunpowder, an immense mass of chalk cliff from the heights down upon the beach, there to form a barrier which may check the drifting of the shingle towards Beachy Head and the east. The ground about Seaford for two miles to the west lies low, and there is nothing to protect it from the inroad of the sea at high tides but a narrow beach bank of shingle. This barrier is becoming gradually weaker in consequence of the tendency of the shingle to drift away, and it has become a matter of urgent moment that this should be stayed. Close to Seaford, on its eastern side, rises a noble line of cliff, in some places 300 feet high, and averaging above 200. It was determined to project a huge slice of the cliff on to the beach, with a view thereby to constitute a groin for the purpose of retaining the shingle and preventing its leaving the bay. The operations have been conducted by the Board of Ordnance. The spot selected is not much above half a mile to the east of Seaford. At a height of about 50 feet above high-water-mark there was driven into the cliff, or excavated, a tunnel or gallery 70 feet long, 6 feet high, 5 feet broad, ascending with a slope of 1 in 3. At the inland extremity it turned right and left in the heart of the cliff, above 50 feet one way and above 60 the other, with a more gentle ascent, the two smaller galleries being 4 feet 6 inches high, and 3 feet 6 inches broad, and the three being in the form of a capital T. At the utmost end of each of the side or cross galleries was a chamber, 7 feet cube, lined with wood; and in each chamber a charge of no less than 12,000 lbs. of gunpowder was deposited; making the distance of the centre of the charge 70 feet from the face of the cliff towards the sea, and about 70 feet above high-water mark. The galleries were 'tamped,' that is, stopped up, with bags of sand, and chalk in bags and loose, to within 50 feet of the mouth, both branches being tamped up, and 20 feet down the large gallery. It was not till 12 minutes past 3 o'clock, that suddenly the whole cliff, along a width or frontage of some 120 feet, bent forwards towards the sea, cracked in every direction, crumbled into pieces, and fell upon the beach in front of it, forming a bank down which large portions of the falling mass glided slowly into the sea for several yards like a stream of lava flowing into the water. The whole multitude upon the beach seemed for a few moments paralysed and awe-struck by the strange movement, and the slightly trembling ground; everyone sought to know with a glance that the mass had not force enough to come near him, and that the cliff under which he stood was safe. There was no very loud report; the rumbling noise was probably not heard a mile off, and was perhaps caused by the splitting of the cliff and fall of the fragments. There seemed to be no smoke, but there was a tremendous shower of dust. Those who were in boats a little way out state that they felt a slight shock. It was much stronger on the top of the cliff. Persons standing there felt staggered by the shaking of the ground, and one of the batteries was thrown down by it. In Seaford, too, three quarters of a mile off, glasses upon the table were shaken, and one chimney fell. At Newhaven, a distance of three miles, the shock was sensibly felt. The mass which came down is larger than was expected; it forms an irregular heap, apparently about 300 feet broad, of a height varying from 40 to 100 feet, and running 200 or 250 feet or more seaward, which is considerably beyond low-water mark. It is thought that it comprises nearly 300,000 tons."

These meagre and most imperfect accounts, as respects the object here in view, will however, it may be hoped, direct future attention to more precise observation of the data required.

Report on Observations of Luminous Meteors, 1857-58. By the Rev. BADEN POWELL, M.A., F.R.S., F.R.A.S., F.G.S., Savilian Professor of Geometry in the University of Oxford.

DURING the year which has elapsed since my last Report to the British Association, I have received a considerable number of communications of meteor observations from various observers, especially, as on so many former occasions, from Mr. E. J. Lowe, as well as from other friends, to whom I am happy to add on this occasion the names of Dr. J. H. Gladstone and Mr. G. J. Symons. The last-named observer is the only one who has recorded any remarkable number as seen at the August period. He has communicated many seen on the 10th of August, 1856, and a still larger number about the corresponding time in 1858, few, however, on the 10th, but a great number on the 13th. In some parts of England the 10th was cloudy.

Of the various theories which have been proposed to explain the nature of luminous meteors, some were alluded to in the Report of last year. At the meeting of the British Association at which that Report was presented, a paper was also communicated by Mr. Daniel Vaughan, of Cincinnati, U. S., in which he proposed another hypothesis which seems to have considerable claims on our attention; it has also been given at large in his recent work entitled "Popular Physical Astronomy."

The main principle of this theory is, that the author conceives the luminiferous ether diffused through space, but in obedience to the law of gravitation condensed round large bodies, in a more intense degree in proportion to their mass. Hence in our system it is immensely condensed round the sun, but feebly round the planets. When in this state of condensation, it is capable of being acted upon so as to produce the most intense light and heat. As existing round our earth, it can only be sufficiently condensed to produce such effects by the immense local compression arising from the rapid motion of meteorites. Hence their luminosity, even when far above the atmosphere; but on entering it, the compression is so great, according to the author's calculation, as to crush them to pieces.

The details of this theory are given in the Appendix (No. 1), by some extracts from the author's work, and also in a letter addressed by him to the author of this Report, with the view to correct some misapprehensions of the theory which have been entertained.

In the Appendix (No.2) there is given a statement which has appeared in print, of a very singular luminous phenomenon, the nature of which it is difficult to conjecture; but it has the appearance of being the account of a plain matter-of-fact witness, who offers no comment or conjecture. To these, one or two other communications have been added.

List of Meteors observed up to August 1857, by G. J. Symons, M.B.M.S., at Camden Town, London.