Smerdon's Passage.-The new mouth is the external entrance, not only of the North Sally-port, but also of a previously unsuspected passage or undervaulting, which, so far as is at present known, varies from 4 to 10 feet in width, and extends in a north-westerly direction. It has received the name of "Smerdon's Passage." On abandoning the tunnel just spoken of, the workmen were directed to commence the exploration of this Passage; and at the end of last month (August 1870) they had advanced about 20 feet into it. The deposit it contains is the common typical cave-earth, having, here and there, a thin patch of stalagmite, but nothing like a continuous floor, and everywhere reaching the roof, or within a few inches of it. It contains a considerable number of pieces of limestone, none of which exceed 10 lbs. in weight, a few subangular and rounded pieces of red grit, and blocks of Old Stalagmite in abundance, some of which measure from 5 to 6 cubic feet. Numerous bones and upwards of 700 teeth were found, the latter of which may be thus apportioned: As in other parts of the cavern, some of the bones were gnawed, some discoloured, and some more or less covered with films of stalagmite. With them were found several agglutinated lumps of bones of very small animals*, coprolites, three limpet-shells, a bit of charcoal, and four good flint flakes. Amongst the foregoing facts there are some on which it is difficult to abstain from speculation. As has been already stated, the late Mr. M'Enery named the Sally-ports from a settled conviction that they led to external entrances in the hill-side. The facts on which he relied were, first, the direction in which they extended, and, second and chiefly, the tunnels, which he ascribed to burrowing animals. The first was obviously not very conclusive; for he could not but be aware that unless the so-called Sally-ports extended considerably beyond the point to which he could penetrate, and without much tortuosity-points on which no opinion could be formed-they must fall far short of the exterior. With reference to the tunnels, even if ascribable to burrowing animals, it by no means followed that they were commenced at, or connected with, the exterior of the cavern; for as there were well-known spots in each of the branches in question where there was no stalagmitic floor, there was no difficulty in supposing the animals to have commenced their burrows in these unprotected localities, to have sunk more or less vertically in the deposit, and at a suitable depth to have proceeded horizontally. In the Fifth Report, mention was made of vertical shafts of this kind+; and that this was the actual mode of operation is now rendered still more probable by the fact that no tunnels occur at or near the inner end of either of the two branches ‡. * One of these lumps was found to contain upwards of 1200 bones. + See Report Brit. Assoc. 1869, p. 203. The Committee are well aware that the cavern is still occasionally frequented by animals. In the Fifth Report they mentioned the annoyance which the visits of a rat had occasioned; bats are often seen flitting to and fro or suspended from the walls, and they sometimes make a meal on the candles; and in the summer considerable numbers of the As has been stated in previous Reports, the Committee have long been familiar with the presence of blocks of stalagmite in the cave-earth, and have inferred from them that an ancient floor of the cavern had been broken up by natural agency before or during the introduction of the cave-earth. There seemed no difficulty in conceiving of a machinery by which such a floor might have been destroyed in the comparatively lofty chambers. For example, it was known that the deposit which the old floor had covered, and on which it had been formed, had been, in some parts of the cavern, partially dislodged, or had subsided so as to leave the floor unsupported; it was also known that blocks of limestone, some of them scores of tons in weight, had from time to time fallen from the roof; and it was not difficult to see that such blocks would break into fragments any such unsupported floor on which they might fall. This, however, utterly fails to account for the destruction of the floor which once existed in at least some of the narrow passages of the North Sallyport. That such floors have been destroyed admits of no question, since, as has been already stated, remnants of them still adhere to the walls, to say nothing of their abundant fragments in the deposit below. That they were not destroyed by the fall of blocks of limestone is obvious from the facts that their remnants on the walls show that they were almost in contact with the roof even as it now exists, and that the roof itself presents no indications that such masses have been detached from them. This problem still awaits solution. Many of the potsherds in the North Sally-port were found in the overlying black mould considerably beyond the point where man could have actually placed or lost them, though not perhaps beyond the point where he might have thrown them, if he could be supposed to have had a motive for doing It seems not improbable, however, that, being, as they were, on a highly inclined plane of very contracted width, their presence in the spots where they were found was due to a participation in a slow and gradual movement of the black mould downwards and inwards, in consequence of the frequent passage of small recent animals. So. There is greater difficulty in accounting for the occurrence of keen-edged flint implements and flakes at and near the external mouth of the North Sally-port. There is every reason to believe that the cave-earth found in the successive chambers at the highest level of the cavern was introduced through the long-known North and South (or Triangular and Arched) Entrances; whence it seems to follow inevitably that at that time the bottom of the valley was but little below these entrances, and was therefore nearly 20 feet above the level of the opening just discovered. That the "implements" are of human origin there is every reason to believe; but it cannot be sup Common Shrew are occasionally observed near the door and in the adjacent thicket. On December 8th, 1869, one of the Superintendents found the workmen in a state of excitement, caused, no doubt, by an unwelcome visit of some infra-human marauder. They had that morning taken to the cavern a pound of candles, of sixteen to the pound, and hung them in the accustomed place. On going to cut one of them, at 3 o'clock, it was found that twelve of the pound were missing, and the condition of the remnants of the wicks was such as to indicate cutting rather than gnawing. Hence it would have been concluded that the loss was due to a human thief, had it been possible for one to have entered the cavern without the knowledge of the workmen. On examination, one of the missing candles was found between some large loose stones beneath the nail on which they were hung, but no trace of teeth-marks could be found on it. Before the men left work the remnant of the pound had been taken, so that not a candle was left; but by what agency, remains unknown; for though a gin temptingly baited was set at the spot, it failed to aid in the solution of the problem. posed that man placed them where they were found under the foregoing conditions; for the bottom of the valley being then far above the low-level entrance, the passages into which it immediately opens were probably inaccessible, and certainly not available for human resort. On the other hand, the hypothesis that the flints were washed there from the upper ehambers appears to be entirely negatived by the fact that, though lodged in a deposit largely charged with stones, they are entirely unrolled and retain their keen edges. It may be added that very few, if any, of the bones found with them show any marks of abrasion, that the implements are more numerous at and near its external entrance than elsewhere in the Sally-port, and that no such phenomenon presented itselt at or near the end of the other Sally-port, which has no external mouth. May not the following be the solution of the problem? The implements and animal-remains found at the new entrance and in the passages connected with it were deposited after it had been laid bare, and are chronologically separated from those in the high-level chambers by an amount of time sufficient to deepen the valley to the extent of 20 feet, but not sufficient to make any change in the fauna of the district, or in the character of the implements which its human dwellers employed. Mr. Ayshford Sanford has continued his identification of the fossils during the past twelve months, and has examined a large number of them. The present state of his health has unfortunately prevented his sending in a Report. Third Report of the Committee for the purpose of investigating the rate of Increase of Underground Temperature downwards in various Localities of Dry Land and under Water. Drawn up by Professor EVERETT, at the request of the Committee, consisting of Sir WILLIAM THOMSON, F.R.S., Sir CHARLES LYELL, F.R.S., J. CLERK MAXWELL, F.R.S., Prof. PHILLIPS, F.R.S., G. J. SYMONS, F.M.S., Dr. BALFOUR STEWART, F.R.S., Prof. RAMSAY, F.R.S., A. GEIKIE, F.R.S, JAMES GLAISHER, F.R.S., Rev. Dr. GRAHAM, E. W. BINNEY, F.R.S., GEORGE MAW, F.G.S., W. PENGELLY, F.R.S., S. J. MACKIE, F.G.S., and Professor EVERETT, D.C.L. (Secretary). MR. G. J. SYMONS, whose observations, extending to a depth of 1100 feet in a well at Kentish Town, were reported at last Meeting, has since repeated his observations at several depths. The first 210 feet of the well (which is 8 feet in diameter to the depth of 540 feet) are occupied by air; and in this portion of the well the second series of observations give temperatures exceeding those observed in the first series by from 2° to 5° F., the excess diminishing as the depth increases. The second series were taken in July and August, whereas the first series were taken in January. It is evident that in this portion of the well, in spite of the precautions taken to exclude atmospheric influences, by boarding over the well and erecting a hut over it, the temperature varies with the seasons, the variations being in the same direction as in the external air, but smaller, and diminishing as the depth increases, but still amounting to 2°.2 at the depth of 200 feet. We can feel no certainty that even the mean annual temperature in this portion of the well represents the temperature in the solid ground. On the contrary, the mean temperature in the well at any depth is probably intermediate between the temperature of the solid ground at that depth and the mean temperature of the external air. It is well that such observations should have been carefully made and recorded in this one instance, if only for the sake of warning; and they show that we cannot expect to attain the object for which the Committee has been appointed by observations in large shafts filled with air. Mr. Symons has also repeated the observations at 250 feet (which is 40 feet under water), and at the depths of 600 feet, 750 feet, and every 50th foot from this to 1100 feet, the lowest point attainable, on account of the mud, which extends 200 feet lower. The differences from the results obtained last year are 2, -—·3, —·4, —·2, —·2, 0, −1, −1, 0; which upon the whole strongly confirm the correctness of the observations. The temperature at 1100 feet is 69°.8, which, if we assume the mean temperature of the surface of the ground to be gives a mean increase downwards of { { 50° { 55.5 feet. 52.9 ⚫0180 ⚫0189 The curve in which temperature is the ordinate and depth the abscissa, exhibits considerable irregularities till we reach the depth of 650 feet, beyond which it is nearly a straight line, and represents an increase of 0187 of a degree per foot. The strata penetrated by the well to the depth to which our observations extend consist of clay, sand, chalk, and marl, besides flints. (See tabular list appended.) Mr. Symons in his Report calls attention to the anomalous position of a column of water increasing in temperature and consequently diminishing in specific gravity downwards, and suggests the inquiry why the warmer and lighter portions do not ascend to the top. The proper reply seems to be that the diminution of specific gravity, amounting to less than 1 part in 50,000 per vertical foot, does not furnish sufficient force to overcome liquid adhesion, and the water is thus able to remain in unstable equilibrium. Mr. Symons intends, during the remainder of the present year, verifying those of his observations which have not yet been repeated, and concludes his Report by remarking that it appears desirable to ascertain, by observations from year to year, whether the temperature at a given depth (say, 1000 feet) remains constant or is subject to minute changes periodical or otherwise—a suggestion which appears fully worthy of being carried out. Mr. Wm. Bryham, Manager of Rose Bridge Colliery, Ince, near Wigan, has taken very valuable observations during the sinking of that Colliery, which is now the deepest excavation in Great Britain. The pricipal results have already been given, in a paper to the Royal Society, by Mr. Edward Hull, Director of the Geological Survey of Ireland, who had previously published some important contributions to our knowledge of underground temperature, and has now consented to become a member of this Committee. Some of the depths, however, have been remeasured since Mr. Hull's paper was read, and I am now enabled, through the kindness of Mr. Bryham, to furnish a rather more accurate report. The temperatures observed and the depths at which they were taken are as follows: Depth in yards. Temperature Fahrenheit. | Depth in yards. Temperature Fahrenheit. All these temperatures, except the first two, were observed during the sinking of the shaft, by drilling a hole with water to the depth of a yard in the solid strata at the bottom. A thermometer was then inserted, the hole was tightly plugged with clay so as to be air-tight, and was left undisturbed for half an hour, at the end of which time the thermometer was withdrawn and read-a mode of observation which appears well adapted to give reliable results. With respect to the temperatures at 161 and 200 yards* (which I have enclosed in brackets to indicate uncertainty), Mr. Bryham informs me that he has some doubt as to the correctness of the thermometer with which they were taken, and that they were not taken in the shaft at the time it was sunk, but in the seams at the depths named. Assuming the surface-temperature to be 49°, we have, on the whole depth of 815 yards or 2445 feet, an increase of 45°, which is at the rate of 0184 of a degree per foot, or a degree for every 54.3 feet. On plotting the temperature curve, including the two observations marked as doubtful, we find that it naturally divides itself into four portions, which are approximately straight lines. The most remarkable of these portions is the second from the top, extending from the depth of 161 yards to that of 605 yards. It embraces 1332 feet, and shows an increase of only 1° for every 86 feet. The third portion, extending from the depth of 605 yards to that of 671 yards, covers only 198 feet, and shows an increase of 1° for every 33 feet. The lowest portion extends from the depth of 671 yards to 815 yards. It covers 432 feet, and shows an increase of 1° in 54 feet. The topmost portion will be affected by the assumption we make as to surface-temperature. Assuming this as 49°, it shows an increase of 1o in 31 feet. It is interesting to compare the Rose Bridge observations with those previously made by Mr. Fairbairn at Astley Pit, Dukenfield, Cheshire, which have been described by Mr. Hull in The Coalfields of Great Britain,' and by Mr. Fairbairn himself in the British Association Report for 1861. The results have been thus summed up by Mr. Hull : "1. The first observation gives 51° as the invariable temperature throughout the year at the depth of 17 feet. Between 231 yards and 270 yards, the temperature was nearly uniform at 58.0. And the increase from the surface would be at the rate of 1° F. for 88 feet. "2. Between 270 and 309 yards, the increase was at the rate of 1° for 62.4 feet. * Further inquiry has shown that these two temperatures must be rejected, as the thermometer with which they were taken was afterwards found (by comparison with other thermometers) to be in error by some degrees. No note was taken of the amount of the error, and the thermometer itself is destroyed. Assuming the surface-temperature as 49°, we have an average increase downwards of 1° in 57.7 feet for the first 558 yards, and of 1o in 48-2 feet for the remaining 257 yards. |