as, or colder than, our own, possessing a rich flora; and by taking the best hardy exotics and establishing them with the best of our own wild flowers in wild or half-wild spots near our houses and gardens, we may produce the most charming results ever seen in such places." On the ground of economy alone there is much to be said for a return to the old-fashioned garden. The hardy perennials, like the clematis, the jasmine, the honeysuckle, Virginian creepers, wild roses, aristolochias, and other climbers, once properly planted, may be left for years, rendering our cottages bowers of beauty and scenting the air with their perfume. Other subjects of similar nature, but of dwarfer habit, may be made to ornament the beds and borders, and, arranged with regard to their periods of blooming, will keep our gardens gay from one end of the year to another. The work is divided into four parts, and Mr. Robinson gives a list of hardy exotic plants, suitable for naturalization in our woods, semi-wild places, shrubberies, &c., with the native country, general characters, height, colour, time of flowering, mode of propagating, and the positions most suitable for each. Several pages are also devoted to the "Garden of British Wildflowers." The subject deserves the attention of landscape gardeners and of those who make horticulture their hobby or amusement. To these we can recommend the book as a guide to the selecting and placing of the various plants mentioned. TRUEG'S HELIORAMA. THE HE instrument herewith illustrated has been styled the "Heliorama." Its name signifies the spectacle of the sun, the application of which to this instrument implies that by its use the apparent relations of the positions of the sun and earth to each other may be determined, and the latitude of any given point upon the earth, and its true time by sun or its true time by clock, may be deduced from these relations. It is compounded of two distinct instruments, one called the "Helioclasis," by which latitude is determined, and the "Hemerophora," by which the time is determined. Instruments hitherto used for the determination of latitude from solar observations by seamen and astronomers can only be used to advantage at mid-day. Observations made before or after this time only approximate the true latitude. The helioclasis does this however at any time the sun is visible between the hours of 6 o'clock in the morning and 6 o'clock in the evening; a very slight adjustment only being necessary, so that, given one minute of sunshine between these hours, the mariner may determine the latitude with precision. A basement bed, A, Fig. 1, carries two side pieces, B, which support a revolving plate C, on which two ares, the one a semicircular brass plate, D, called the "Equatorial Gnomon," the other, E, an arc of 50°, called the "Cliseologet," are so adjusted that the TRUEG'S HELIORAMA. centre of each touches the periphery of the other hours in the summer season. from within, their radii being equal. The equatorial over, be shifted about its centre by moving the This arc may, moregnomon stands perpendicular on the plate, its pointer, G, so as to adjust the horologet to the time diameter touching the surface of it, and bisecting of a correct clock. The arcs, I K, over which the the cliseologet at right angles. The point of pointer, G, moves, have marked thereon days of bisection is degree 0, from which, on both sides, the year, to which if the pointer be placed, the degrees are counted up to 25. The plate bears a horologet, H, will be shifted to correspond with the throughout the whole year. When the instrument pointer is moved. L is the gnomon, placed perlist of the declination of the sun for every tenth day time of a correct clock for that day to which the is set up the basement bed must be level, and the manently at right angles with the horologet, as front directed towards the south, which purpose the shown, and made to give correction for refraction compass, F, in the basement is intended to serve; by making the radius of its arc one thirty-second then the list on the plate must be consulted. If we greater than that of the horologet. The effect of this have, for instance, April 1st, the list tells us that is to cast the shadow backward at morning, and foron that day the sun's declination is four and four-ward at evening, so that the shadow shall fall on the tenths degrees, the plate must be then turned until 6 o'clock mark on the horologet at precisely when the shadow of the sun, cast by the gnomon, falls on the sun rises and sets at the equinoxes. On the that degree. Look at the degree of latitude marked side piece, C, Fig. 2, is an are which shows by the to the pivot of the plate, B, and moving with it, the same time that the opposite hand or pointer, on the side pieces, facing the west. A hand attached pointer, M, the height of the celestial equator at of observation is actually situated. indicates that degree of latitude on which the place Fig. 1, shows the latitude. The invention has been instrument will be most serviceable if kept in its American Patent Agency. At sea, the patented in the United States, through the Scientific proper direction (with regard to north and south) by a large magnet. In order to make the correction for refraction, the graduation on the arc, on the side piece, C, is so made that in the distribution of degrees, 33' of arc are lost, so that on the place where 89° 27' would come, 900 would appear. The refraction of the sun's rays corresponds to this marking, as it is at 20°, 21"; at 30°, 33"; and at 90°, 33". disc, 16' may be made, if deemed necessary, by Another correction for the radius of the sun's subtracting that number of minutes in the graduation of the arc, on C, so that 90° are marked at a real distance from 0° of 89° 11'. The second instrument of the heliorama is the hemerophora, which is an improved sun-dial. It shows not only the correct sun time but also the mean time-that is, the time which a correct clock shows. In construction (Fig. 2) it is an inverted helioclasis, for that are which there casts the shadow is here inverted in order to receive it, while that arc which there receives the shadow, being inverted, is here made to cast the shadow. The deviation of the sun time from the clock time, is corrected by an apparatus which moves the arc that receives the shadow, called "Horologet," and sets it so as to show the time of a correct clock. A movable hand, G, points to the different dates of the year. No sundial until this has been able to show the exact sun time at every hour of the day, and at any season of the year. At any moment, when the sun shines, the hemerophora or heliorama shows what former sun-dials could only accomplish with accuracy at one moment of the day, and it indicates the mean time besides the sun time. The arc, H, which is called the "Horologet," is divided regarding the hours as follows:-From 6 o'clock a.m. to 6 o'clock p.m. is 180°. The intervening space is divided into 15° divisions for hours, and these divisions are subdivided into quarters. The horologet, H, is more than a semicircle, so as to gain space for the inscription of at least one hour more for the morning and one more for the evening, in order to mark time for longer than twelve A MAGNETIC PARADOX.* THE instrument I wish to describe I have called a "magnetic paradox" because the phenomenon presented by it is the apparent repulsion of soft iron by a magnet. The apparatus consists of a compound magnet in a box, and when pieces of soft iron are placed on the box over the poles they become magnetic by induction, and are attracted by the magnet, but if a bar of soft iron not by itself magnetic be brought near to the pieces of soft iron they will leap away from the inducing magnet and become attracted to the soft iron bar which is farther away from the magnet in the box, so the pieces of iron appear to be repelled. The explanation, which is simple, demonstrates the duality of magnetic force, and demonstrates also that magnetic force is transmitted by induction. If we place a piece of soft iron near to the pole of a magnet the magnet develops the magnetic forces resident in the iron by separating them, and the iron is attracted only by virtue of the forces resident in the iron itself, and to the extent to which these forces are separated by the inducing force to which they are subjected. If we bend the magnet, bringing the lower pole of the magnet around and over the piece of soft iron, the magnet forces resident in the iron will be more strongly developed, but the piece of soft iron if midway will not be attracted, as the forces on either side will be equal; but if the piece of iron be brought nearer to the one pole than to the other magnetic attraction will be exhibited. If we return to the previous case, and approach the piece of soft iron by an iron bar, the magnetic forces separated and rendered active in the piece of soft iron will develop the magnetic forces resident * Paper read before the British Association. in the iron bar, and if the bar opposed no resistance The iron bar also collects the magnetic lines of force issuing from the magnet, and consequently it exerts a greater amount of force than any individual magnet of which the compound magnet in the box is composed. This can be shown by placing a piece of iron direct on the pole of one of the bars and removing it from the magnet by the superior attractive force of the iron bar, and if only the thickness of a piece of paper intervene between the poles and the piece of soft iron, the piece of iron will leap from the magnet and become attached to the iron bar. In such the water; and it is well-known in practice that a part only of some indefinitely extended curve vessels have proved successful whose lines differ must be taken. In 1870 an improvement in the very widely from wave-lines. It is, therefore, construction of such curves was made by which that desirable that methods should be devised of con- defect was overcome; it consisted in the introduc structing by mathematical rules, based on the laws tion of one or more additional pairs of foci, involv of the motion of fluids, a great variety of curves ing the combination of at least five sets of coLS. possessing the requisite property of fairness, and ponent stream-lines. By this device it is possible not limited to the wave-line shape. Such has been to imitate the longitudinal lines of actual vessels the object of a series of researches that have been by means of complete closed curves without using communicated to the Royal Society at different portions of indefinitely extended curves; and thus dates since 1862. They relate to the construction the knowledge of the motion of the particles of of what it is proposed to call stream-lines. A water, as shown by the stream-lines that lie outside stream-line is the track or path traced by a particle the closed lines representing the form of the vessel, of water moving in a smoothly and steadily flowing becomes more definite and accurate. The lecturer current. If, when a ship is gliding ahead through mentioned that the idea of employing four foci and the water with a certain speed, we imagine the ship upwards had been suggested to him by the experito be stationary, and the water to be flowing astern ments of Mr. Froude on the resistance of boats past the ship in a smooth and steady current with modelled so as to resemble the form of a swimming an equal average speed, the motions of the ship and bird, for which purpose stream-lines with four foc of the particles of water relatively to each other are especially adapted. It has been proposed to call are not altered by that supposition; and it be- such lines Cycnogenous Neoids; that is, ship-lis comes evident that if the form of surface of the curves of shapes like that of a swan. skin of the ship has the property of fairness, all the curves, when adapted to fine-ended ships, the out. tracks of the particles of water as they glide over foci-that is, the foremost and the aftermost, are that surface are stream-lines, and the surface it- situated in or near the stem and sternpost of the self is one containing an indefinite number of stream- vessel, which are represented in plan by small lines; or, as it has been called, a stream-line sur-horse-shoe-like curves, as if they were rounded off face. It is also to be observed that when we have at the corners, instead of being square, as in ordideduced from the laws of the motion of fluids, the nary practice. The inner foci are situated respecrelations which exist between the forms of the tively in the fore and after body. When the foci of stream-lines in different parts of one current, and the longitudinal lines of a vessel have been deter between those forms and the velocities of the par- mined, the proportion borne by the aggregate energy ticles as they glide along different parts of those lines, of the motion impressed on the particles of the we know the relation between the form and speed water to that of the motion of the vessel herself of a ship whose surface coincides with a certain set can be approximately determined. The lecturer NAVAL ARCHITECTURE. of those stream-lines, and the motions of the parti- next proceeded to explain the bearing of some of HE following is the substance of the lecture on cles of water in various positions in the neighbour- the mechanical properties of waves upon the deLiverpool:-The art of designing the figures of illustrated by diagrams the methods of construct- are taken in combination with those of stream-lines. ships has been gradually developed by processes ing stream-lines. These methods were based upon It has long been known that ships in moving resembling those called "natural selection" and the application to stream-lines in a current of fluid, through the water are accompanied by trains of the "struggle for existence," in the course of thou- of a mathematical process which had previously waves, whose dimensions and position depend on the sands of years, and has arrived in skilful hands at been applied by Mr. Clerk Maxwell to lines of speed of the vessel; but the first discovery of prea perfection which leaves little more to be desired, electric and magnetic force. A current of fluid is cise and definite laws respecting such waves is due when the object was to design a ship that should represented on paper by drawing a set of stream to Mr. Scott Russell, who published it about twentyanswer purposes and fulfil conditions which have lines so distributed that between each pair of them five years ago. The lecturer next described, in a previously been accomplished and fulfilled in the there lies an elementary stream of a given constant general way, the motions of the particles of water course of practical experience. But cases now volume of flow. Thus, while the direction of flow in a series of waves, and illustrated them by means frequently arise in which new conditions are to is indicated in any given part of the current by the of a machine contrived for that purpose. He showed be fulfilled, and purposes accomplished beyond the direction of the stream-lines, the velocity of flow is how, while the shape of the wave advances, each limits of the performance of previous vessels; and indicated by their comparative closeness and wide- individual particle of water describes an orbit in such cases the] process of gradual development ness apart, being evidently greatest where those of limited extent in a vertical plane. The by practical trials made without the help of science lines lie closest together, and least where they are periodic time of a wave, its length, the depth to is too slow and too costly; and it becomes neces- most widely spread. If, upon the same sheet of which a disturbance bearing a given ratio to the sary to acquire and to apply scientific knowledge paper, we draw two different sets of stream-lines, disturbance at the surface of the water extends, of the laws that regulate the actions of the vessel these will represent the currents produced in one and the speed of advance of the wave, are all on the water and of the water on the vessel. and the same mass of fluid by two different sets of related to each other by laws which he explained. Amongst the questions thus arising are the follow- forces. The two sets of lines represent a network; He stated that Mr. Scott Russell had shown that, ing:-What ought to be the form of the immersed and if through the angles of the meshes of that when the vessel moved no faster than the natural surface or skin of a ship in order that the particles network we draw a third set of stream-lines it can speed of advance of the waves that she raised. of water may glide smoothly over it? And the be proved from the principle of the composition of those waves were of moderate height, and added form of such a surface being given, how will it motions that this third set of lines will represent little or nothing to her resistance; but, when that affect the motions of particles in its neighbourhood; the current produced in the same mass of fluid by limit of speed was exceeded, the waves, and the and what mutual forces will be exerted between the the combination of the forces which, acting sepa- resistance caused by them, increased rapidly in particles of water and that surface? Practical rately, would produce the currents represented by magnitude with increase of speed. Professor Ranexperience, unaided by science, answers the first the first two sets of stream-lines respectively. The kine's opinion regarding these phenomena is, that question by saying, that the surface ought to be- third set may be called the resultant stream-lines, when the speed of the vessel is less than, or equal to long to a class called "fair surfaces" (that is, sur- and the first two the component stream-lines. the natural speed of the waves raised by her, the resistfaces free from sudden changes of direction and of Suppose, now, that a third set of component stream-ance of the vessel consists wholly, or almost wholly, curvature), of which various forms have in the course lines are drawn representing the current produced of that arising from the friction of the water gliding of ages been ascertained by trial, and are known to by a third set of forces; this will form a network over her skin; and he considers that this opinion is skilful shipbuilders. That answer is satisfactory, with the previously drawn resultant stream-lines; confirmed by the results of practical experience of so far as it goes; but, in order to solve problems and a set of lines drawn through the angles of the the performance of vessels. The wave-motion, involving the mutual actions of the ship and the meshes of this new network will represent the being impressed once for all on the water during water, something more is wanted; and it becomes resultant current produced by the combination of the starting of the vessel, is propagated onward, necessary to be able to construct fair surfaces by the three sets of forces; and so on to combinations like the swell of the ocean, from one mass of water geometrical rules based on the laws of the motion of any degree of complexity that may be required. to another, requiring little or no expenditure of of fluids, and to express their forms by algebraic In order to draw a system of stream-lines suited for motive power to keep it up. But when a ship is equations. There have been many very early the longitudinal lines of a ship, three sets at least driven at a speed exceeding the natural speed of attempts to do this; but, not being based on the of component stream-lines must be combined. One the waves that she raises, the waves, in order to laws of hydrodynamics, they resulted merely in of these is a set of parallel straight lines, represent accompany the ship, are compelled to spread the finding of empirical rules for reproducing, ing a uniform current running astern with a speed obliquely outwards instead of travelling directly when required, forms that had previously been equal to the actual speed of the vessel. A second ahead; and it becomes necessary for the vessel, at found to answer in practice, and did not lead set consists of straight lines radiating from a point the expense of her motive power, to keep conto any knowledge of the motions of the par- called a focus in the fore part of the vessel, and tinually originating wave-motion afresh in preticles of water or of the forces exerted by and they represent the diverging motion that is pro- viously undisturbed masses of water; hence the upon them; and they had little or no advantage duced by the ship displacing the water near her waste of power found by experience to occur when over the old process of modelling by the eye and bows. The third set of component stream-lines a ship is driven at a speed beyond the limit suited hand, and of "fairing" the lines with the help consists of straight lines converging towards a to her length. This divergence, or spreading sideof an elastic rod called a "batten." As regards second focus in the after part of the vessel; and ways of the train of waves, has a modifying effect this process, indeed, the mathematical methods to they represent the motion of the water closing in on the stream-lines representing the motions of the be referred to are to be regarded, not as a substitute astern of the ship. The resultant stream-lines particles of water. It causes them, in the first for it in designing the form of a ship, but as a thus produced present a great variety of forms place, to assume a serpentine form; and then, means of arriving at a knowledge of the mutual all resembling those of actual ships, having instead of closing in behind the ship to the same actions between her and the water, which the old all possible proportions of length to breadth, distances from her course at which they had been process is incapable of affording. The earliest and all degrees of bluffness and fineness at the situated when ahead of her, they remain permamethod of constructing the figures of ships by ends, ranging from the absolute bluffness of a nently spread outwards. In other words, the parmathematical rules based on hydrodynamical prin. sort of oval to a bow and stern of any degree ticles of water do not return to their original dis ciples was that proposed by Mr. Scott Russell about of sharpness that may be required. It has been tance from the longitudinal midship plane of the twenty-five years ago, and since very extensively proposed to call stream-lines of this sort Oogenous vessel, but are shifted laterally and left there, unch practised. It consisted in adopting for the longi- Neoids, that is, ship-like lines generated from an as the sods of earth are permanently shifted sidetudinal lines of a ship curves imitated from the out- oval; because any given set of them can be gene-ways by the plough. The place of the water which lines of waves in water. The motions which sur-rated by the flow of a current of water past an oval thus fails to close in completely astern of the vessel faces formed upon this model impressed on the solid of suitable dimensions. The properties of is supplied by water which rises up from below, water were known to a certain degree of approximaforming a mass of eddies rolling in the wake of the tion. Those "wave-lines," however, although they ship. The mathematical theory of the steadiness were fair curves in the sense already mentioned, of ships has been known and applied with useful were by no means the only fair curves, but were results for nearly a century; but in the course of only one class out of innumerable classes of curves the last few years it has received some important having the property of gliding smoothly through additions, due especially to the researches of Mr. Tthis subject delivered by Professor Rankine, at hood of that shiva The then explained and signing of vessels, especially when these properties these curves were investigated in 1862. They have, Froude on the manner in which the motions of the waves affect the rolling of the vessel. A stiff ship is one that tends strongly to keep and recover her position of uprightness to the surface of the water. A steady ship is one that tends to keep a position of absolute uprightness. In smooth water these properties are the same; a stiff ship is also a steady ship in smooth water. Amongst waves, on the other hand, the properties of stiffness and steadiness were often opposed to each other. A stiff ship tends as she rolls to follow the motions of the waves as they roll; she is a dry ship; but she may be what is called uneasy through excessive rolling along with the waves. The property of stiffness is possessed in the highest degree by a raft, and by a ship which, like a raft, is very broad and shallow, and whose natural period of rolling in smooth water is very short compared with the periodic time of the waves. In order that a ship may be steady amongst waves, her natural period of rolling should be considerably larger than that of the waves, and in order that this property may be obtained without making the vessel crank, the masses on board of her should be spread out sideways as far as practicable from the centre of gravity: this is called "winging out the weights." A vessel whose natural period of rolling in smooth water is only a little shorter or a little longer than that of the waves has neither the advantages of stiffness nor those of steadiness; for she rolls to an angle greater than that of the slope of the waves, and her condition is specially unsafe if her natural period of rolling is a little greater than that of the waves; for then she tends to heel over towards the nearest wave-crest, to the danger of its breaking inboard. This is called rolling "against the waves." The most dangerous condition is that of a vessel whose period of rolling in smooth water is equal to that of the waves which she encounters; for then every successive wave makes her roll through a greater and greater angle, and under these circumstances no ship can be safe, how great soever her stability. All these principles have been known for some years, through Mr. Froude's researches. The lecturer exhibited a machine which he had contrived for illustrating them, in which the dynamical conditions of vessels of different degrees of stiffness and steadiness were approximately imitated by means of a peculiarly constructed pendulum hanging from a pin, whose motions imitated those of a particle of water disturbed by waves. THE MANUFACTURE OF CHLORINE. Chemical Section of the British Association He had being equal, trade will gravitate to those places out by the clerk in attendance-and immediately where labour is the cheapest; and other countries opened. It contains a telegraphic message, sent are now so rapidly approaching England in facilities here for transmission to some other wire. This of transport and in the development of mineral pneumatic tube at present is only extended to offices wealth, that the time is at hand when any forced half a mile round, but as this half mile is in the increase in the price of labour would be fatal to the busiest part of the City, an area in which it is difficontinuance of our commercial supremacy. Sir cult to get along fast by foot-passengers, porterageWilliam then proceeded to point out the mischievous work is done in seconds as compared to minutes by effect of union rules for the destruction of a spirit this fleet mechanical messenger. Eventually all the of emulation among workmen, and said that the great district post-offices will be connected with the unions would pursue a much more rational policy central office by pneumatic tubes, thus vastly if, instead of repressing the ability and energy of accelerating the speed of the telegrams. In addiindividual members, they were to foster and encou- tion to the offices within half a mile of Telegraphrage such qualities with a view of organizing co- street, which are thus served by this aerial Meroperative manufacturing societies. With the aid of cury, the head office at St. Martin's-le-Grand is profrugal habits it would be quite possible to raise the vided with a tube. The great submarine cables, necessary capital. The sum annually spent in this such as the Atlantic, the Indian, and all the marine country in the payment of labour amounts to lines wishing to use the central office as a means of hundreds of millions; and a small percentage saved forwarding messages, will have lines of tube to this out of that amount would quickly raise large capi- room for that purpose. If the reader remembers tals for investment in co-operative trade. Sir his old pea-shooter days, he will understand their William glanced at the prospect that better educa- principle of action in a moment. If he blows he tion in the future would render workmen better impels the pea, if he sucks he draws it up into his fitted than at present for such enterprises, and re- mouth. Pressure and suction are the two forces ferred then briefly to the acts of violence and used in this pea or message-shooter of our maturer coercion occasionally committed under the sanction days. The telegraph message comes in a round of trade-unions. He considered such practices plug-box, covered with carpet or flannel, so as just to be the exception and not the rule. Passing on to the consideration of the law of patents, which he propulsive power lies in the depths of the establishto make it fit loosely the tube. The suction and described as another kind of restrictive legislation, ment, in the shape of a steam-engine. Sir William expressed his own opinion as being adverse to patents, and said that, whatever difference there might be about the propriety of abolishing them, there could be no doubt that the present law with regard to them is disgraceful. Patents are granted without inquiry or discrimination; and the result is that they exist by thousands. Many of them are untenable, and others of doubtful by Mr. Walter Weldon. validity; but, as they cannot be set aside without a process was one for the manufacture of chlorine by lawsuit, a bad patent often answers its purpose just means of a perpetually-regenerated reagent conas well as a good one, and a spurious protection is sisting mainly of a compound containing the acquired in defiance of law and justice. In a great elements of peroxide of manganese and lime, number of cases the invention is so imperfectly and which was previously unknown. developed that the patent remains inoperative and described the process last year at the Exeter dormant, and simply blocks the way of other inven- meeting, when it was in operation at only two tors; for no one will labour to give value to an in- works. It is now either in operation or on the vention when a patentee is lying in wait to reap the point of being adopted at almost all the works in advantage as soon as the practical difficulties are this country, and at a number of works in France surmounted. As to the alleged analogy between and Germany. In consideration of the fact that copyright and patent right there is none whatever the production of chlorine will probably be com in regard to obstructive effect. Copyright involves pletely revolutionized by the Weldon process, and no monopoly of ideas, and does not narrow the considering, likewise, that chlorine is largely prefield of authorship, but patent right most seriously pared in the neighbourhood of Liverpool and in narrows the field of invention. Having thus glanced other parts of Lancashire, the author had agreed at the impolicy of protection, whether applied to to the request of Prof. Roscoe that he should subcommerce, to labour, or to invention, Sir William mit to the section a brief account of the practical T before ting social substan Conga under more extended experience, and of the developHE following is the substance of a paper read concluded by deprecating all interference with results which the process had been found to yield Newcastle last week:ment which it had undergone during the year. The author first described the apparatus employed, and exhibited a small model of it, and then proceeded to state that the chloride of manganese, which results in the ordinary preparation of chlorine, and which is generally acid, is neutralized by adding to the liquor finely divided carbonate of lime. The liquor then consists of a neutral mixed solution of chloride of manganese and chloride of calcium, and contains, in suspension, a large quantity of sulphate and smaller quantities of of iron alumina. The clear solution, after settling, is oxidized by passing into it a blast of atmospheric air from a blowing engine, and heated, if necessary, by a current of steam. Milk of lime is then run into the oxidizer until the liquid ceases to give a manganese reaction with solution of bleaching powder. A further quantity of milk of lime is added, and ultimately from 80 to 85 per cent. of the manganese is converted into peroxide. mixture is allowed to settle, the chloride of calcium solution forming the supernatant liquid is run off, and the residual black mud containing the manganese peroxide is used in the stills where hydrochloric acid is decomposed and chlorine gas produced. A residual liquor, such as was commenced with, results, and the round of operations is begun again; and so on, time after time indefinitely. After giving an outline of his mode of treating still liquor, Mr. Weldon described at considerable length the details of the process, both as to quantities of materials employed and obtained, and the nature of the chemical compounds formed at different stages of the process. As explained by Prof. Roscoe, the principle upon which the process depends is that, although when alone, the lower oxides of manganese cannot be oxidized by air and steam under the ordinary pressure to the state of dioxide, yet this is possible when one molecule of lime is present to each molecule of oxide of manganese. The manganons oxide is precipitated from the still liquors with the above excess of lime, and by the action of steam and air on this, a black powder, consisting of manganese dioxide and lime, or calcium manganite (MnO2 Ca O), is formed. This compound is again capable of generating chlorine from hydrochloric acid, and thus the chlorine process is made continuous with a working loss of only 23 per cent. of manganese. SIR WILLIAM ARMSTRONG ON THE Sir William commenced by saying that if men legislated only for the common good of the human race, industry and trade would be left as free as air; but that unfortunately local and class interests assert themselves in the fabrication of laws which under the specious plea of protecting home industries have for their object to benefit particular sections of the community at the expense of others. The immediate of Trice of the protected article,tion is to increase the posed on the consumer, and every industry is prejudiced in which the article is required. After pointing out the uselessness of the demand for so-called "reciprocity" among nations in respect of free trade, he went on to say that the restrictions imposed on particular industries by trade-unions were closely allied, both in nature and effect, to restrictive laws on commerce; and that when these societies attempt, by their rules, to give fictitious value to labour, they commit the error of contending with natural laws, which cannot be violated without very injurious consequences. Labour, physical and mental, is the creative element of our nature, and is the foundation of all value. Therefore, the price of labour determines the price of commodities, and whether commodities are raised to a fictitions price by protective enactments of the Legislature, or by protective rules of tradeunions, in both cases the consumers suffer for the benefit of producers. The workers in any trade have, indeed, a right to combine for the purpose of raising the price of their labour; but they should remember that the policy of raising wages by combination will operate against themselves when adopted by workers in other trades. If all kinds of labour were by this means artificially enhanced in price, the effect would be that wages would be universally higher and commodities universally dearer, and the receivers of wages, even if the trade of the country suffered no diminution, would be little better off than before. It is only by stealing a march on other classes of labourers that those of any particular trade can improve their position by raising the price of their labour beyond the limits imposed by the natural laws of supply and demand. We can scarcely expect that trade societies should be restrained by considerations of political economy from using every means in their power to make the most of their labour; but the liability to drive away trade bears so directly on their interests that it cannot be too carefully considered. Other things and by maintaining that the greatest good to the THE "INSTRUMENT ROOM" OF THE HIS room, the most sensitive spot in the whole transmits intelligence from all quarters of the the visitor is listening to the clatter of one-half of The A short discussion followed the reading of the paper, in the course of which Mr. Gossage stated that his experiments on the improvement of the chlorine process had extended over thirty-five years, and he was glad Mr. Weldon's efforts had been attended with such a large measure of success. AN ACCOUNT OF THE SILVER COINS OF ENGLAND FROM THE DEPARTURE OF THE ROMANS TO THE CONQUEST. AF FTER the final departure of the Romans from England, about 450 A.D., the Britons being in a defenceless state were compelled to ask the assistance of the Saxons, who, having once got a footing here, brought the Britons into subjection to their laws and customs, and after a time formed the country into seven kingdoms, or, according to some reckonings, eight. Until the establishment of these petty kingdoms, it is probable that the Roman money circulated in the island, and was imitated by the Saxons, as coins are occasionally found which can scarcely be attributed to any other Source. Of the Saxon period the earliest coins are known as sceattæ, which is a pure Saxon term, being used by them as we use the term money. Considerable doubt exists as to whether the sceatta were brought over with them or struck by them after their arrival. Some of them were obviously struck before the introduction of Christianity, or they would probably have the cross in some part of their type (see engravings of Sceattæ I. to V.) Others having the cross as a distinguishing mark, were struck in all possibility after (see VI. to X.). That a great many are clearly copied from Roman coins is very evident. The meaning of the few letters on them has never been explained. It is not easy to state their value, but they probably passed at a little less than a penny. They weigh from 12 to 20 grs. troy, and were in all probability issued between the beginning of the sixth and end of the seventh century. We will now proceed to the coins of the various kingdoms of the Heptarchy, struck by the respective monarchs, bearing their names, and in some instances the place of mintage, which may be attributed with some degree of surety to their localities and proper personages. Each kingdom will be taken by itself, and Kent being the earliest established, with that we will begin. KINGS OF KENT. ETHILBERHT I., from 568 to 615. Only one coin is known of this king; it is a sceattæ of silver, weight nearly 19 grs. (see 1); it is extremely rare; it is without the Christian symbol, and was struck in all likelihood before Ethilberht's conversion, which is said to have taken place about the end of the sixth century. It should be observed that the attribution of the above coin is not at all sure, and it may belong to some other personage. ETHILBERHT II., from 725 to 760. Of this king only one coin is known; it is a penny, but it is doubted; if genuine, it is the first known penny (see 2). King's head to right, and name "Ethilberht." Reverse: the wolf suckling Romulus and Remus, with the title "Rex." The next king of whom any certain coins are known, is EADBERHT OR ETHELBERHT, from 794 to 798, whose coins are pennies, having the king's name and titles in three lines on the obverse. Reverse: Moneyer's name, with ornaments (see 3 and 4). CUTHRED, from 798 to 805. The coins of Cuthred have the king's head to right with "Rex," or "Rex Cant" (for Kent), others are without the head, and have in the centre a small cross within an inner circle. Reverse: Moneyer's name. There are four different types known (see 5, 6, and 7), all pennies. BALDRED, OR BELDRED, from 805 to 823. Of this king there are five types of pennies as follows. On them he is styled "Rex," or "Rex Cant." 1. King's bust to right. Reverse: "Drvr Cits," for Doroverina Civitas (Canterbury). This is the first place of coinage mentioned on a Saxon coin (see 8). 2. Reverse: a small circle from whence issue five to seven rays (see ENGLISH MECHANIC, page 190, Vol. XI., query 3750). 3. Cross with pallet in each angle. Reverse: The same four limbs issuing, ending in Saxon Y (see 9). 4. Cross crosselet. Reverse: plain cross (see 10). 5. Plain cross on each side, The kingdom of Kent terminates with Baldred, who was conquered by Egberht in the year 823. MERCIA. Mercia is the next kingdom of which any coins are known; all are silver pennies, and commence with coins bearing the name of Eadvald, who is supposed to be the same personage as Ethelbald. Opinions are divided, and it is very likely that the coins attributed to this king belong to some other person, of whom no records exist. IMPROVED BRICK-MAKING MACHINE. EADVALD, from 716 to 757. The types of the coins bearing his name are1. The name "Eadvald," with the title "Rex," in three lines. Reverse: Moneyer's name in a quatrefoil (see 11). 2. Reverse: Moneyer's name between the limbs of an ornamental cross. OFFA, from 757 to 796. Is the first king of Mercia to which any coins can with certainty be ascribed. His types are very various, too much so to be described here; but enough of his coins will be engraved to give the reader a fair view of his types, and enable him to distinguish any coins belonging to this king. Some of the types are very beautiful, and the heads are engraved with some view as to the light and shade required to produce a good portrait. To his having been a resident in Rome, and to the works of Italian artists supposed to have been brought home with him, the fineness of his types are usually ascribed. 1. The king's head, with or without an inner circle: usually with his name and title, and moneyer's name (see 12 and 13). Sometimes the moneyer's name is placed on the obverse, when the king's name is placed on the reverse, which are very various (see 14). 2. The king's name and title in two or three lines. Reverse: The moneyer's name, also in two or three lines, accompanied with some ornament. COENWLF, from 796 to 818. His coins present a great many varieties of types, somewhat like unto Offa's, but muchinferior in work manship. They usually bear a head on the obverse, but with some exceptions; no place of mintage is stated on the coins. The reverses are occupied by various ornaments and the moneyer's name. The obverses having no head have invariably the Saxon y within a circle, see 22 for these and 23 for those having his head. CEOLWLF, 819. This king reigned only a little more than a year and considerable doubt exists amongst collectors in their views of distinguishing the coins of this monarch from those of Ciolwlf, but those given here are those generally attributed to him:1. Obverse: The king's head. Reverse: Moneyer's name in three lines (see 25). 2. Obverse as No. 1; reverse, two long crosses, &c. (see 26). 3. Obverse, as No. 1; reverse, square enclosing five pellets, a cross issuing from each angle (see 27). His style is Rex, with M. for Merciorum. The reverses have the moneyer's name, but no place of mintage. BEORNWULF, 820 to 824. The coins of this king are pennies. His style is Rex or Rex M. No place of mintage occurs on his coins. His types are: 1. Obverse: the king's head. Reverse: Cross crosslet, moneyer's name (see 28). 2. Obverse: as No. 1. Reverse: Moneyer's name in three lines (see 29). LUDICA, 824 to 825, who reigned some eighteen months, has left u two specimens of his coinage. 1. Obverse: king's head. Reverse: Cross crosslet and moneyer's name (see 30). 2. Reverse: Moneyer's name in three lines (see 31) He is styled on his coins, which are of very bad workmanship, Ludica, Rex, or Rex Me.* IMPROVED BRICK-MAKING MACHINE. THIS machine was patented February 23, 1970, TH of Chicago, Ill. The machine can be driven by a lever by the United States Brick Machine Company sweep propelled by horses as well as by steam of water power, though when driven by horses it can not, of course, be worked up to its full capacity *This notice of a portion of the silver coins of Eng land will be continued at intervals till completed. |