a long pause, during which the performer changed her shape several times. In the A condition, the curves of her body were approximately circular, and regular from side to side. At one time a flat margin was seen all round, and a bump in the middle. B shows this form in section, and it is something like the figure given by Mr. Buckton in his valuable work. Fig. C represents the appearance of a quiescent female surrounded by more than fifty eggs. A finally got back into this lumpish shape.

00

898%

B

In a day or two the egg-layers became scarce, and then vanished altogether, but scores of larvæ and pupæ continued their depredations on the hedge. Many oak-leaves were spotted all over with orange-red instead of the fresh greeny yellow first noticed. These exhibited no egglayers, and the change of tint was the result of more complete destruction of the chlorophyl and cell tissue. A winged form was common on these leaves.

The writer has oak in various hedges made on the Sussex plan, but only one hedge was conspicuously attacked by the Phylloxera, and the large oaks, so far as could be seen, were not affected. The eggs, when first laid, were smooth and glossy, but after a little while they become pitted. None hatched while under several hours' observation, and when, a few days later, more specimens. were wanted, none could be found. Buckton gives the size of the Queen Mother as 0.030 x 0.012, and describes her as very small and flask-shaped, which corresponds with A turned upside down. This form, however, was only exhibited in my specimens when the egg-laying was in process.

at the base, but the upper oval was certainly a walled depression, and appeared so with half-inch, sixth, and one-twelfth objectives. Two minute projections carry the hairs at the tip. The legs are short, with two claws and minute pulvilli. The visibility of the oval wall and depression depends upon its position under the microscope. A full-faced view is plain enough; a profile one at best looks like a very slight notch.

The antennæ are three-jointed. Fig. D shows two joints, the terminal one having a curious oval depression near the top, bounded by a raised wall. This does not exactly correspond with the description in Mr. Buckton's book, which, in describing the genus Phylloxera, says: "Antennæ three-jointed... The third joint much the longest, roughly imbricated, with a circular tubercle near its base, and a longer, somewhat inconspicuous, tubercle, towards its apex." The specimens I found had little projective "tubercles," from which a hair sprang,

These Phylloxera are, according to Buckton, "in a qualified sense, exclusively oviparous, for the true ovum applies only in strictness to the produce of the perfect sexes." The pseudo-eggs laid here in August are thus to be regarded as only more backward stages of the least advanced young excluded by the aphides with their limbs still folded up.

The ringed forms, now on the oak leaves, are imagoes— the Latin plural looks awkward, and the word may, I hope, be treated as English.

"Late in the autumn," says Mr. Buckton, "the second brood of a late (winged) female occur, and these contain eggs of different sizes, disclosing the true males and their females." The Queen, or founder of a new brood, "is the produce of the single egg laid by the true female." The various forms are depicted in Mr. Buckton's work. I do not know whether my specimens belong to the species punctata, as they do not exactly correspond with his figures.

It is satisfactory that hitherto the English representatives of the genus Phylloxera have not been guilty of any serious injury like their relatives on the continent, which played such havoc in the vineyards. Speckling some leaves of our oaks is very different from the underground assaults on the vine-roots, against which no complete defence has yet been found. The mouth of Phylloxera is like that of the aphis.

The possessor of a microscope, unless very busy with some special study, should always be on the look-out as an observer of what is going on in minute life. Something fresh and interesting is sure to be the reward. For example, a glance at a mushroom-bed made in a frame and kept dark with a cover, showed some small oddlooking brown bodies moving clumsily about as soon as the light was allowed to enter. They proved to be small green flies (dipters)-whose name I do not know-and they were so thickly covered with mites that they could scarcely waddle, and not a bit of their skin could be seen. Two sorts of mites were visible with a handglass

-one a Gamasid, like those common on bees and beetles, brown, with hard skins, and about as big as the heads of minikin pins. These were in clusters of half-dozen or more, and, beside them, were swarms of a smaller transparent and very lively mite. These last had their foremost legs longer and finer than the others, which is not uncommon. Watching their movements under an inch and a-half power sufficed to show that the motion of their legs differed somewhat from that of the others. They acted as pioneers, and rapidly changed the direction of motion, when, as often happened, they touched the legs of fellow-travellers. The antennæ being short, these legs did some of their work, as well as that of locomotion.

For permanent preservation, the Phylloxera and mites were mounted in balsam. A small ring of stout paper was gummed on to a glass-slide, and a minute quantity of Canada balsam put in the middle. To this the insects were cautiously transferred, and more balsam added to fill up the shallow cavity, and a coverglass put on. This treatment sufficed for a small bit of oak-leaf with the Queen Mother and her eggs, as shown

in A. For quick treatment of dissected parts, such as antennæ or mouth-organs, a drop of saturated solution of potassic acetate answers, with a cover kept in its place by a ring of gummed paper.

FINDING THE WAY AT SEA. BY RICHARD A. PROCTOR. (Continued from p. 150.)

UNE

INFORTUNATELY, the longitude is not determined so readily. The very circumstance which makes the determination of the latitude so simple introduces the great difficulty which exists in finding the longitude. I have said that all places in the same latitude have the same celestial scenery; and precisely for this reason it is difficult to distinguish one such place from another, that is, to find on what part of its particular latitudecircle any place may lie.

If we consider, however, how longitude is measured, and what it really means, we shall readily see where a solution of the difficulty is to be sought. The latitude of a station means how far towards either pole the station is; its longitude means how far round, from some fixed longitude, the station is. But it is by turning round on her axis that the earth causes the changes which we call day and night; and therefore these must happen at different times in places at different distances round. For example, it is clear that if it is noon at one station it must be midnight at a station half-way round from the former. And if any one at one station could telegraph to a person at another, "It is exactly noon here," while this latter person knew from his clock or watch, that it was exactly midnight where he was, then he would know that he was half-way round exactly. He would, in fact, know his longitude from the other station. And so with smaller differences. The earth turns we know from west to east, that is, a place lying due west of another is so carried as presently to occupy the place which its easterly neighbour had before occupied, while this last place has gone farther east yet. Let us suppose an hour is the time required to carry a westerly station to the position which had been occupied by a station to the east of it. Then manifestly every celestial phenomenon depending on the earth's turning will occur an hour later at the westerly station. Sunrise and sunset are phenomena of this kind. If I telegraph to a friend at some station far to the west, but in the same latitude, "The sun is rising here," and he finds that he has to wait exactly an hour before the sun rises there, then he knows that he is one hour west of me in longitude, a most inexact yet very convenient and unmistakable way of speaking. As there are twenty-four hours in the day, while a complete circle running through my station and his (and everywhere in the same latitude) is supposed to be divided into 360 degs., he is 15 degs. (a 24th part of 360) west of me; and if my station is Greenwich, he is in what we, in England, call 15 degs. west longitude.*

But what is true of sunrise and sunset in the same latitudes and in different longitudes, is true of noon whatever the latitude may be. And, of course, it is true

*In this case, he is "at sea (which, I trust, will not be the case with the reader), and, we may suppose, connected with Greenwich by a submarine telegraph in course of being laid. In fact, the position of the Great Eastern, throughout her cable-laying journeys, was determined by a method analogous to that sketched above.

of the southing of any known star. Only, unfortunately, one cannot tell the exact instant when either the sun or a star is due south or at its highest above the horizon. Still, speaking generally, and for the moment limiting our attention to noon, every station towards the west has noon later, while every station towards the east has noon earlier, than Greenwich (or whatever reference-station is employed).

I shall presently return to the question how the longitude is to be determined with sufficient exactness for

safety in sea voyages. But I may digress here to note what happens in sea voyages where the longitude changes largely. If a voyage is made towards the west, as from England to America, it is manifest that a watch set to Greenwich time will be in advance of the local time as the ship proceeds westwards, and will be more and more in advance the farther the ship travels in that direction. For instance, suppose a watch shows Greenwich time; then when it is noon at Greenwich the watch will point to twelve, but it will be an hour before noon at a place 15° west of Greenwich, two hours before noon at a place 30° west, and so on-that is, the watch will point to twelve when it is only eleven o'clock, ten o'clock, and so on, of local time. On arrival at New York, the traveller would find that his watch was nearly five hours fast. Of course, the reverse happens in a voyage towards the east. For instance, a watch set to New York time would be found to be nearly five hours slow, for Greenwich time, when the traveller arrived in England.

In the following passage these effects are humorously illustrated by Mark Twain::

"Young Mr. Blucher, who is from the Far West, and on his first voyage" (from New York to Europe) "was a good deal worried by the constantly changing shiptime.' He was proud of his new watch at first, and used to drag it out promptly when eight bells struck at noon, but he came to look after a while as if he were losing confidence in it. Seven days out from New York he came on deck, and said with great decision, This thing's a swindle!' 'What's a swindle?' 'Why, this watch. I bought her out in Illinois-gave 150 dols. for her, and I thought she was good. And, by George, she is good on shore, but somehow she don't keep up her lick here on the water-gets sea-sick, maybe. She skips; she runs along regular enough till half-past eleven, and then all of a sudden she lets down. I've set that old regulator up faster and faster, till I've shoved it clean round, but it don't do any good; she just distances every watch in the ship, and clatters along in a way that's astonishing till it's noon, but them "eight bells" always gets in about ten minutes ahead of her any way. I don't know what to do with her now. She's doing all she can, she's going her best gait, but it won't save her. Now, don't you know there ain't a watch in the ship that's making better time than she is; but what does it signify? When you hear them "eight bells," you'll find her just ten minutes short of her score-sure.' The ship was gaining a full hour every three days, and this fellow was trying to make his watch go fast enough to keep up to her. But, as he had said, he had pushed the regulator up as far as it would go, and the watch was 'on its best gait,' and so nothing was left him but to fold his hands and see the ship beat the race. We sent him to the captain, and he explained to him the mystery of 'ship

*

*Because set to go fast." Of course, the other watches on board would be left to go at their usual rate, and simply put forward at noon each day by so many minutes as corresponded to the run eastwards since the preceding noon.

time' and set his troubled mind at rest."

"This young

man," proceeds Mr. Clemens, apropos des bottes, "had asked a great many questions about sea-sickness before we left, and wanted to know what its characteristics were, and how he was to tell when he had it. He found out."

I cannot leave Mark Twain's narrative, however, without gently criticising a passage in which he has allowed his imagination to invent effects of longitude which assuredly were never perceived in any voyage since the ship Argo set out after the Golden Fleece. "We had the phenomenon of a full moon," he says, "located just in the same spot in the heavens, at the same hour every night. The reason of this singular conduct on the part of the moon did not occur to us at first, but it did afterwards, when we reflected that we were gaining about twenty minutes every day, because we were going east so fast; we gained just about enough every day to keep along with the moon. It was becoming an old moon to the friends we had left behind us, but to us Joshuas it stood still in the same place, and remained always the same." Oh, Mr. Clemens, Mr. Clemens! In a work of imagination (as the "Innocents Abroad" must, I suppose, be to a great extent considered), a mistake such as that here made is perhaps not a very serious matter; but suppose some unfortunate compiler of astronomical works should happen to remember this passage, and to state (as a compiler would be tolerably sure to do, unless he had a mathematical friend at his elbow), that by voyaging eastwards at such and such a rate, a traveller can always have the moon "full" at night, in what an unpleasant predicament would the mistake have placed him. Such things happen, unfortunately; nay, I have even seen a work, in which precisely such mistakes have been made, in use positively as a text-book for examinations. On this account, our fiction writers must be careful in introducing science details, lest peradventure science teachers (save the mark!) be led astray.

It need scarcely be said that no amount of eastwardly voyaging would cause the moon to remain always "full as seen by the voyager. The moon's phase is the same from whatever part of the earth she may be seen, and she will become "new," that is, pass between the earth and the sun, no matter what voyages may be undertaken by the inhabitants of the earth. Mr. Clemens has confounded the monthly motion of the moon with her daily motion. A traveller who could only go fast enough eastwards might keep the moon always due south. To do this he would have to travel completely round the earth in a day and (roughly) about 50 minutes. If he continued this for a whole month, the moon would never leave the southern heavens; but she would not continue "full." In fact we see that the hour of the day (local time) would be continually changing,-since the traveller would not go round once in twenty-four hours (which would be following the sun, and would cause the hour of the day to remain always the same) but in twenty-four hours and the best part of another hour; so that the day would seem to pass on, though very slowly, lasting a lunar month instead of a common day.

(To be continued.)

LIABILITIES OF TELEPHONE COMPANIES.-According to exchanges, the telephone companies in the States may be held liable for injuries to passengers by the fall of their wires in the public street. In a recent case, in which this was decided, the wires gave way in consequence of the weight of the ice produced by water thrown upon them by a city fire department whilst extinguishing a fire.

R

RAMBLES WITH A HAMMER.

BY W. JEROME HARRISON, F.G.S.・・・
THE ROCKS OF THE LICKEY.
(Continued from page 135.)

ETRACING our steps to the Lickey ridge-and here the New Rose and Crown offers the only chance of refreshment for some distance round-we continue our south-easterly walk over the camel-backed hills which succeed one another in that direction. To the east the Triassic sandstones and clays form a plain extending to Birmingham, while on the west lies a narrow valley above which rises the Bromsgrove Lickey, a parallel chain of hills to that upon which we are walking, but of much greater altitude-the highest point of the "Lower Lickey" (upon which we are now, in imagination, standing) being about 500 feet above sea-level, while the height of the "Bromsgrove Lickey" is about 900 feet. At one spot on the road where a little lane branches off to the right, another patch of the breccia at the base of the Llandovery sandstone is seen, showing that this rock once extended right over the hills, although it has now been almost entirely denuded off them. The quartzite supports but a scanty vegetation, conspicuous amongst which are the bilberry bushes, which in the autumn furnish an abundant harvest of blue berries to many busy gatherers. Rabbits

flit among the ferns, watched by a kite which hovers overhead, and the whole scene causes us to envy the occupiers of the trim villas which are springing up here and there round the Lickey, but to hope that the ridge itself too steep and bare for cultivation-will long be preserved as a free and "happy hunting-ground" for the lover of nature.

Turning to the left, when we arrive at a steep, almost precipitous descent, we once more reach the main road, at the eastern foot of the hills at Rednal. Continuing southwards, we note a quarry in which the quartzite is grandly bent and contorted, showing that we are here close to the line of fault which runs along this edge of the ridge. A mile more and we reach Kendal End, where a divergence to the right, past the farm-house, should be made to examine a patch of Wenlock limestone, which must owe its position here to a system of faults. It lies in an old quarry, now planted over with trees [see Map (3), ante, p. 134]. The high road now must be regained, and in ten minutes we reach Barnt Green House, close to the railway-bridge, the residence of Mr. Thompson, agent to Lord Windsor, who owns much land about here. We have to thank this gentleman for the permissionwhich would doubtless be accorded to any respectable visitor to examine the interesting rocks exposed along the brook-course which traverses the grounds [see Map (4)]. In many districts the sections of the strata exposed by running streams afford the only plain indications of the succession of the rocks, and in a new district it is always well to first walk up the available brooks and rivers. Pursuing this plan, we find forming the bed and banks of the purling brook a singular dark-grey rock, which readily breaks into rhomboidal blocks, being traversed by many joints. Sometimes this rock is of a red or yellowish colour, and it is frequently more or less spotted. It has an earthy. look, and altogether reminds one of a compacted volcanic ash, such as forms many square miles of the country round Vesuvius. But if active volcanoes once existed in this corner of Worcestershire, and erupted the mass of ashes which now, hardened into solid rock, lies beneath

our feet, it must have been at a very early geological period, for these old volcanic ashes can be proved to underlie, and therefore to be older than, all the other rocks here visible. The quartzite, we know, is of great anti

FINAL OPERATIONS FOR THE REMOVAL OF FLOOD ROCK.

underlie the quartzite. Now, at Nuneaton

at the Wrekin, volcanic rocks are also found beneath the quartzite. Moreover, in Wales, in Charnwood Forest, and elsewhere, a great mass of bedded volcanic rocks-ashes, lavas, &c. are found to underlie the Cambrian strata, and are assigned to a Pre-Cambrian period, which includes the oldest stratified rocks of which we have any knowledge.

Thus it seems that, peeping out in this little corner of the Lickey at Barnt Green, we have a representative of the earliest-formed series of rocks known upon the globe -the great Pre-Cambrian Formation-which are everywhere unfossiliferous. Above them, and constituting the ridge called the Lower Lickey, comes the Cambrian quartzite, whose thickness is probably between 300 and 400 feet. Resting unconformably on the quartzite are Upper Silurian strata; above them come the coalmeasures, which form the extreme southerly termination of the South Staffordshire coal-field; next we get Permian rocks, crowded with fragments of the older beds beneath; and, above all, the Trias, or New Red Sandstone, in whose Bunter pebble-bed we see a great conglomerate of quartzite pebbles, many of which were undoubtedly derived from the ridge of the Lickey, or its extension.

For although this quartzite of the Lickey is now only exposed as a tiny range of hills, yet in carboniferous times it formed part of a land-barrier which extended across central England from the hills of Charnwood to the Malverns. Of this old land, the Hartshill range, Dosthill, the Lickey, the Silurian bosses at Dudley Castle and the Wren's Nest, the Wrekin range, and the Longmynd hills of Shropshire, are isolated fragments which owe their present position to the combined action of the volcanic forces by which they have been upheaved, and the forces of denudation by which they have been laid bare. But various deep borings-more especially those in Leicestershire, and between Leicester and London— have revealed the presence of a continuation of these old rocks beneath the surface at no great depth, and they form the floor of all the country between the Thames Valley on the south, and a curved line joining the Malvern with the Charnwood hills on the north.

It is an interesting task to search in the newer stratathe Permians and the Trias-for the relics of this old land, which reared its head proudly above the waters in which they were deposited. In Bangham-lane, leading to Northfield, two or three miles north of the Lickey, there is a section of Permian breccias from which quite a suite of Silurian fossils may be collected, showing that Silurian rocks formed the margin of the sea in which the Permian strata were laid down.

If the geologist can devote a whole day to the examination of the Lickey, he may, instead of returning from Barnt Green station, walk along the western side of the Lickey ridge back towards Rubery. At the northern end of the ridge several fine boulders are to be seen lying

on the roadside or in the waste corners of fields. These boulders are mostly blocks of rock which have been transported from North Wales by ice during the last Glacial Period. Such blocks lie thickly, too, over the country round Northfield, where the "Great Stone Inn" takes its name from the mass of Welsh felstone which now rests near its door.

of a mile from

is one of the most formidable of the many obstructions by which all the commerce passing through Hell Gate has been menaced. This rock forms a very irregular obtuse cone, only a small portion of the apex of which comes above water. This formation and its location in the bend of the river almost in the centre of a swift current at each change of the tide make it an object of great dread to pilots. The work of removing this rock was begun in 1875, and after unnecessary and costly delays caused by the failure of Congress to appropriate sufficient from the entire excavation to year year has been completed, all the drill-holes have been bored, and all that remains to be done is the charging of the holes with explosives, removing the plant, and dredging the broken rock after the firing. The total cost of the improvement will be about 1,000,000 dols.

money

The method pursued may be briefly described, the familiarity of our readers with the undertaking rendering a detailed account uncalled for. A shaft was sunk at the highest point of the rock to a depth of sixty feet below water level, and from this shaft galleries were extended parallel with and at right angles to the current. These galleries are twenty-five feet between centres, and extend under all the rock to be removed. It was not the design to remove the rock as much as possible by means of these tunnels-owing to the fact that it would be cheaper to dredge the broken rock after the explosionwhich were only expected to serve as passageways honeycombing the rock and through which access could be had to all parts in order to place the powder. Absolute regularity in the spacing of the galleries could not be maintained owing to inequality in the texture and formation of the rock. The plan view in the accompanying illustrations shows the present condition of the excavation, and, being drawn to scale, it presents a good idea of the magnitude of the work.

Thus was formed an immense chamber, averaging about 10 ft. from floor to ceiling, having a stone roof averaging about 15 ft. in thickness, and supported by 467 rugged and massive columns. In this chamber, running parallel with the East River, are twenty-four galleries, the longest measuring 1,200 ft., and running at right angles to the stream are forty-six galleries, the longest of which is 625 ft. The area covered by the chamber is about nine acres. The aggregate length of the galleries

is 21,670 ft.

The mining operations were not attended with unusual risk either to the men or the work; the main danger was from the flooding of the mine through the opening of a fissure, or the meeting with a rock "keyed the wrong way," which would admit the water in quantities too great to be handled by the pumps. Fissures were frequently encountered, but fortunately none of excessive size; the large holes were plugged with wood, loose filling, such as cement, being unavailable because of the great pressure of water, some 26 lb. to the square inch. To escape the drippings, and in some cases the pourings, from the roof, and to enable the visitor to walk dry-shod through the small brooks running down some of the galleries, he is, through the kindness of those in charge of the work, encased in rubber from head to foot.

The north-eastern portion of the excavation, having an area of about one acre, was through rock very irre