their petioles, we caused the current to traverse them; but the leaves did not fold up, the petioles did not fall, and the plants seemed insensible to the electric action. We then varied the experiment, and instead of employing the direct current of the battery, we used an induced current obtained by the aid of a very small Ruhmkorff's coil. The results were then quite different. Scarcely had the current commenced when the leaflets began to fold together, and the leaf-stalks drooped down along the stems. These movements were quickly propagated from one end to the other of the plants. According to this experiment the plants are sensible to electric disturbances, and behave under such conditions like animals.

We then wished to see whether the application of the electricity for a longer or shorter time would give rise to any special phenomena, and we exposed three of the plants to electric action for varying periods. The first plant received the current from the Ruhmkorff coil for five minutes, and was then left to itself. For more than a quarter of an hour it remained in a state of prostration, but gradually its leaflets reopened, the leaf-stems lifted themselves up, and in about an hour it reassumed its natural appearance, and seemed none the worse for the shocks it had received.

A second plant was similarly treated for ten minutes, and then left alone. The state of prostration in this case lasted for an hour, and it was not till the expiration of that time that the leaflets began to open, and the leaf-stalks to rise, and these movements seemed to be accomplished with greater difficulty than in the preceding case. The plant was evidently fatigued, and did not fully recover for two hours and a half. The third plant was electrified for twenty-five minutes and then left to itself. In this case we waited in vain for its restoration-the prolonged electric action had destroyed its irritability, and even its life, for the next day we found it withered, and blackened, as if struck by lightning.

The fourth plant was reserved for an experiment which proves that electric disturbance acts upon plants, as it does upon animals. It is known that man, and other animals, exposed to the anaesthetic action of ether, become insensible to induction currents, even when strong. We desired to ascertain if it was the same with the sensitive plant. With this object in view we placed a plant under a bell-glass with two openings, through which two copper wires could convey the electric current to it. A few drops of ether were sprinkled in the glass, and in a short time the plant experienced the anææsthetic action of that substance, for when shaken it did not close its leaves, or manifest any sensibility. In this state we passed the induction current through it, but it gave no sign of

sensitiveness. The petioles remained straight, and the leaflets continued open.

These fresh experiments came in aid of others which have been made on the same subject, and supply an argument in favour of those who consider the movements observed in these plants to be produced by the operation of organs analogous to those which animals possess.

ARCHEOLOGIA.

THE past month has witnessed the congresses, or annual meetings, of the three great ARCHEOLOGICAL ASSOCIATED BODIES, the British Archæological Association, the Archæological Institute (the branch, or rather division, from the former), and the Cambrian Archæological Association, which was formed on the model of the first. We have stated, on a former occasion, that the three Associations had, quite unknown to each other, selected the same place of meeting, Hereford, for the present year; but that, as the Cambrian Association, by the prior publication of its claim, had secured the right to Hereford, the two others were obliged to seek their fortunes elsewhere. The British Archæological Association announced its intention of meeting at Ludlow, in Shropshire; and its congress was accordingly held during the week, from the 29th of July to the 3rd of August, under the presidency of Sir Charles H. Rous Boughton, Bart., of Downton Hall, near Ludlow-an old member, and one of the Vice-Presidents of the Association. The Archæological Institute (very unadvisedly, we think) chose to meet at Hull during the same week which had been previously chosen for the meeting of the older body, the British Archæological Association. The Cambrian Association met at Hereford from Monday, August 12th, to Saturday, August 17th, under the presidency of Lord Saye and Sele, who was compelled, by unavoidable causes, to depute his authority to the Rev. Archer Clive, of Whitfield. As a tolerably numerous meeting, which everybody enjoyed, and which gave satisfaction to all concerned in it, that of the Archæological Association appears to have been the most successful. It may be questioned if any one of these meetings has added to our archæological knowledge, or even if such meetings generally have that effect; but they are pleasant reunions, in which people who are more or less attached to the same pursuits meet and commune together. They have the tendency, perhaps, to make people talk on antiquities instead of studying them, or rather before studying; but this inconvenience is somewhat compensated by the circumstance that they excite a local feeling of interest in the numerous monuments of antiquity which still exist, and many of which have been exposed to the risk of destruction through local ignorance.

The meeting of the Cambrian Association was made the occasion

of excavations into a very large TUMULUS at Thruxton, by the directions of the Rev. Archer Clive, of Whitfield, on whose estate it stands. Thruxton is a village about eight miles to the south-west of Hereford. The tumulus resembles the larger monument of the same class at St. Weonard's, farther to the south of Hereford, which was opened a few years ago under the direction of Mr. T. Wright, and an account of which will be found in the first volume of his "Essays on Archæological Subjects." Mr. Wright was at Thruxton two or three days before the meeting, after the men had been set to work excavating, and gave some directions, or suggestions, which seem to have been followed; but the examination has evidently been as yet very imperfect. There appears to have been in the centre of the mound a small dome of stones, which covered a mass of ashes, the result of the cremation of the dead body, just the same as was found to be the case in the great barrow at St. Weonard's. One or two pieces of pottery, Roman in character; parts of an iron horseshoe; and a portion of a glass vessel-the latter very improperly carried away by some accidental visitorwere among the remains found in the tumulus. It is to be hoped that whoever has the glass will immediately restore it, as it may be of very great importance in establishing the true character of the monument. All the evidence yet obtained leads us to believe that it belongs to the Roman period, and points to its identity of character with the tumulus at St. Weonard's, and several other large tumuli on this border. This at Thruxton, like many of the others, stands very near the parish church. This circumstance admits of an easy explanation. These barrows were, no doubt, in early times, looked upon with a large amount of superstitious veneration by the population of the neighbourhood, and people probably assembled at them at different periods. The early Christian missionaries sought to turn these assemblages of people to account by erecting their church near to the tumulus, and so draw the attention of the people assembled there to their preaching.

We are very glad to be able to announce that the excavations at Wroxeter, on the site of the ROMAN CITY OF URICONIUM, are recommenced. We owe this chiefly to the munificent liberality of Joseph Mayer, of Liverpool, who recently made a very handsome contribution of £50 to the excavation funds. It is to be hoped that others will follow his example, and that the good work will not again meet with so long an interruption; though it will never be carried to the extent which the history of our country requires, until the Government itself steps forward to supply sufficient funds. Through a mistake in the first measuring out of the land which the Duke of Cleveland granted for excavating, the greater part of the line of the Old Wall, or the wall which divided the Basilica from the Baths and other buildings to the south, was left out of the limits; the consequence of which was that some important buildings could not be explored in a satisfactory manner. This has now been remedied, and a large room has been opened, which fronted the Forum, and adjoined the room which has been called the enameller's shop. The portion of this room yet uncovered is of small

extent, for it was found necessary to withdraw the men for the requirements of the harvest; but enough has been done to show that it is possessed of very considerable interest. It appears also to have been a workshop, for the remains of erections built of stone, somewhat like forges, have already been found; and amongst the loose objects scattered about the floor was the bowl of an iron ladle, which appeared to have been used for pouring out melted metal. Among the other articles which have been gathered from the small extent of excavation yet made, are a great quantity of earthenware and glass-some of the latter of very interesting character; and, among the pottery, two handsome ornamental bowls of Samian ware; two iron rings; a very curious finger-ring, made of amber; a bronze fibula; an ornamented bone roundel; a bronze scale-pan, with three equidistant holes; two hair-pins; a small pellet of enamel; a white disk of bone, like a button, but without a shank; nine Roman coins; and a piece of sandstone, with a fragment of an inscription. The buried part of the Old Wall has also been uncovered, and all that has been yet done, though very small in extent, gives promise of important discoveries.

A very remarkable discovery has recently been made on the site of WIGMORE ABBEY, in Herefordshire. In digging for some works of construction, the workmen came among some very extraordinary subterranean buildings, which soon assumed the form of a very large passage, wide and lofty, and was followed for, we believe, at least a hundred feet; and, with the old legendary notions about abbeys and castles, was assumed to be a passage for secret communication between Wigmore Abbey and Wigmore Castle, a distance of about a mile and a half. However, a little consideration was sufficient to convince us that it was simply the great drain of the important Abbey of Wigmore; and, as such, it is a very remarkable monument of the internal economy of these great medieval establishments. T. W.

PROGRESS OF INVENTION.

IMPROVED APPLICATION OF SUPERHEATED STEAM.-It is found more economical, as far as fuel is concerned, to increase the pressure of steam by superheating it, than by causing the evaporation of an additional quantity of water. There is a limit, however, to the degree of temperature to which the superheated steam can be raised since, if its temperature is too high, lubrication will be imperfect, or impossible, on account of the charring of the oil. Superheating is applied very effectually in a new engine recently constructed for the water supply of the city of Paris. This, like Woolf's engine, consists of two cylinders, the steam passing from one into the other; but instead of the steam passing directly from one cylinder to the other, after leaving the first, it is made to traverse tubes which are placed in the furnace near the chimney.

Thus, the steam is not only heated to the temperature it had when it entered the first cylinder, and therefore has no tendency to lose its vaporous form, but it is superheated, so as to have an increased pressure. And this restoration of heat, and superheating, is the source of the greater economy, as the heat required for the purpose costs nothing, being taken from the products of combustion just before they are about to escape into the chimney, and to carry off and waste any heat still remaining in them.

COMBINATION OF HORSE AND STEAM POWER FOR LOCOMOTIVES ON ORDINARY ROADS.-The great difficulty attending the introduction of steam on ordinary roads, as far as the public is concerned, is the danger of accidents of a most serious kind from the least interruption of attention on the part of the engineer in charge of the vehicle. On a curved or crowded road there must be constant changes of direction, without which collisions, or other dangerous effects, will certainly take place. With a vehicle drawn by horses, their intelligence, not less than that of the driver, is effective; and in cases in which the driver is negligent, or even incapable, from sleep, or some other cause, the horses may, and often do, bring the vehicle safe through every peril. This consideration has suggested the utilization of the intelligence of the horse-which, unlike that of the engine-driver, is undoubtedly ever occupied only with things present by a means which M. Séguier has recently brought under the notice of the Academy of Sciences. The horse is to be attached to the locomotive, not for the purpose of giving the least assistance in drawing the vehicle, but with the sole object of aiding in its guidance it will therefore undergo no fatigue. A shaft, which is placed in front of the steam-carriage, and to which the horse is yoked, is so connected with the steam machinery, that when the horse advances, the steam is turned on, when he moves back, it is turned off; and when he turns to either side, the mechanism required to turn the carriage in the proper direction is thrown into action.

RENOVATION OF THE POLISHED SURFACE OF GLASS.-Hydrofluoric acid in the form of gas, and that dissolved in water, has very different effects on glass. As a gas, it entirely removes the polish, rendering the glass incapable of transmitting the images of objects; as an aqueous solution, it removes the old surface, without destroying the polish, but, on the contrary, rendering it more brilliant. For this purpose a very dilute acid must be employed; if tolerably concentrated, it will eat a hole in the surface of the glass on which it is placed; but this hole will have a brilliant appearance. This property, possessed by hydrofluoric acid in solution, has suggested it as an excellent material for cleaning glass which has been tarnished by time or bad usage.

APPLICATION OF ELECTRO-MAGNETISM TO THE MANUFACTURE OF IRON. -It has been found by recent experiments that electro-magnetism can be used with excellent effect in the manufacture of iron; the process being facilitated, and rendered more perfect, while, at the same time, fuel is economized. An opening is made in the smelting furnace, and opposite to this opening is placed an electro-magnet,