aware that blame did not rest with the Board o foreign, 20,426. Numerous bridges and light-houses deserved to be the labours of the editor of the Trade, but that the delay was attributable to the and other public works are in progress. A telegraphic" Horological Journal" were calculated to make circumstance that no penalty attached to dis- communication with Brequet's dial instruments it more popular in the future among the workmen regard of the repeated requests made by the Board has been laid between Yokohama and Yedo, and of Clerkenwell and elsewhere. The tendency of to the companies to send in the necessary infor- messages in both English and Japanese are re- the journal was to expand the mind of the workmation. We do not know whether the expendi-ceived and transmitted by Japanese operators, man, to create in him a taste for science, and byture on stationery in the Board of Trade offices is who acquire western arts with great facility. and-bye he apprehended that the institute would very profuse, but if the clerks use quill pens a They are excellent ship carpenters, clever printers be better supported for what it could do for the good many bundles must have been used, and and type founders, and adapt themselves most promotion of the art of horology. No man was many reams of paper and much time that ought readily to new modes of working. Great improve- doing more to promote a proper feeling or a proto have been put to better account, in entreating ments are being made in the towns and the settle- per respect for the science of horology than Mr. the companies to send in their returns. The issue ments. Districts are being drained, streets Strachan. The chairman then read the inscripof the basketsful of humiliating and importunate drained and paved, and, at Osaka, lighted with tion upon the watch, which was as follows:epistles commenced, probably, about a year and a kerosine lamps and adorned with trees. At Naga-"Presented by the members of the British Horohalf since, and many letters and reminders have saki, a patent slip has been opened, and thirty logical Institute to R. Strachan, Esq., as a mark been sent since, it may be supposed, to the same vessels docked in it in the course of the year. A of esteem and gratitude for many years' arduous railway offices, to be flung into the waste basket large dry dock is also in progress, 460ft. long, honorary services as editor of their journal. A.D. of the secretary or his assistant as soon as opened. 110ft. wide, and 76ft. at the entrance, with 26ft. 1870." The miserable result of all this expenditure of of water over the sill at high water spring tides. Mr. Strachan, who spoke at considerable time, stationery, and dignity is that the returns The natural products and the manufactures are length and with much feeling, said he had at for 1868, not 1869, have been issued towards the numerous, important, and valuable, and the inter- first discouraged the idea of presenting end of September, 1870. Not only so; the returns course with Europeans is producing the doubly him with a testimonial, well knowing that he was as published are "neither fish, flesh, nor good red valuable result of stimulating native produce and of very little intrinsic value to the institute, but herring." They purport to be for 1868, but have increasing a desire for the products of the west. when it was persistently adhered to by the council many returns for 1869 mixed up with those of Japan is an improving country-it may not be he considered that it would be unbecoming to stay 1868, and are not even partial returns applicable doubted; and it may be that the time may come, the progress of the movement. He was still, howto either the one year or the other. And besides, although it has scarcely arrived as yet, when the ever, at a loss to know what he had done to deserve in the first part of the return, which purports to words of a native worthy may be true-" Among so magnificent a present. The duties he had pergive an account of the share and loan capital of the 3,000 countries in the world, there is none formed for the institute were of a comparatively the railway companies of England and Wales, which excels Japan!" light character, and such as they were they had some companies send in their returns as stated as always been welcome to them. He had never at December 31, 1868, others as at December 31, songht or desired any tangible recognition of what 1869, and seventy companies send in no returns he did in connection with the institute, for which whatever. The columns are nevertheless carefully THE HOROLOGICAL INSTITUTE. all the members worked or contributed con amore, added up, and the results brought out at foot from the returns of 1868 and 1869 mixed up, and N December, 1867, at a meeting of the members merely desiring to assist in an association for useIN of this institute it was resolved that a testimo-ful aggregate results, such as affect societies and the "statistical department of the Board shows nial be presented to Mr. Strachan for his valuable, nations rather than individuals. He could only by the totals how 30 apples are the product of 16 gratuitous services as editor of the "Horological thank them most cordially for their handsome and apples and 12 pears! This division of the return, Journal," and it was suggested that a handsome valuable testimonial; and since "a thing of and all the others indeed, are utterly worthless, and valuable gold watch would be a very suitable beauty" is said to be " a joy for ever," a thing of and ought not to have been printed. Its prepara-present, and a committee was at once appointed utility and beauty ought to be doubly a joy. After tion and issue is a sheer waste of public money; to carry the proposition into effect. In an account sketching the causes which led to his association it had been better far to have sold the paper to the of the Horological Institute which appeared in the with the institute and reiterating his appreciation butter dealer without the intervention of the MECHANICS' MAGAZINE for May 22, 1868, this re- of the honour they had conferred upon him, both printer. solution was alluded to as follows:-" The journal as their guest and by their present, he resumed is ably edited by Mr. R. Strachan, who gives his his seat amid much applause. services gratuitously, and who does his work well -two conditions of things which we rarely find combined. We are happy to learn that a movement has been set on foot, and which, we trust, will be well supported, to present Mr. Strachan with a tangible recognition of his valuable services." We have now much pleasure in recording that the presentation of the testimonial took place on the 9th inst., when a number of the members met at dinner at the Angel Hotel, Islington. Mr. E. D. Johnson, F.R.A.S., vice-president, occupied the chair, Messrs. J. Jones, of the Strand, E. J. Thompson, member of the Metropolitan Board of Works, Holliday, Holdsworth, Warman, Mercer, Storer, and other leading members of the institute being present.

Mining activity in various parts of the world induces the belief that the world's coal stores are about to be more freely drawn from in countries both far east and far west of Britain than they have been hitherto. In the far west, or connected with it, for instance, a Brazilian Collieries Company is being formed to work the colliery and other mineral property of the "Arroyo dos Ratos," in the district of San Jeronymo, Province of Rio Grande, South Brazil. The company, under their concession, expect to be able to secure mining rights over an area of 5,000 acres. A 4ft. 8in. seam is now being worked at a depth of 16 fathoms. Ironstone and limestone, it is said, also abound in the locality. Turning to the far east, Messrs. Glover and Co. are now working by the "western method" at Takashima, about five miles from Nagasaki, Japan, an 8ft. seam of excellent coal for steam purposes, which is reached at a depth of 150ft. The machinery they have erected will enable them to raise 500 tons a day. The following is an analysis of this coal: Specific gravity 1.231, carbon 77.59, hydrogen 5.28, oxygen 3.26, nitrogen 2.75, sulphur 1.65, approximate ash 8.49. Mr. Madden, chief engineer of H.M.S. "Ocean," reports it to be equal to English north country coal. Several of the native princes of Japan have also ordered European machinery for the improved working of their mines, and a decided impetus has been given in that country to mining enterprise. Now that the Japanese have emerged from the disastrous influences of civil war, they seem to be devoting themselves with spirit to the cultivation of the arts of peace. During the last year the Prince of Awa had a small steamboat built, of 80 tons, with 23-horse power engines. The Prince of Satzuma has been building a cotton mill, with 2,000 spindles, and a 12-horse power engine; and others of the princes are interesting themselves in like enterprises. The trade at the open ports is increasing steadily, and in all respects satisfactorily, as appears from the reports of the consuls just published. The foreign trade may be reckoned at about 10 millions sterling, employing 1,043,405 tons of shipping. Above half of the trade is in British hands, and British ships have by far the best share of the carrying. The increase in the British shipping employed in 1869, as compared with 1868, is at some of the ports quite marvellous. At Nagasaki in 1869, there were 384 British vessels entered and cleared, of 143,960 tonnage, with cargo of £666,763 value; foreign ships entered and cleared, 297, tonnage 286,821, value of cargo £433,499; crews, British and

We have not space to notice the other speeches of the evening, and we will merely express our satisfaction at the manner in which the committee of the institute very unostentatiously has carried out, though with considerable delay, the resolution of the members. The watch is a fine specimen of English work, having compensation balance and the most approved keyless mechanism, and the inscription is an excellent specimen of engraving. It has been made entirely by members of the institute, in this respect being unique of its kind.

THE BRITISH ASSOCIATION.

OUR

NATION.

BY PROFESSOR TYNDALL.

UR readers were informed in our last issue that Professor Tyndall had been appointed to deliver the first lecture of the meeting at the Philharmonic Hall, Liverpool, on the 16th inst. this he did before crowded audience, Professor Huxley in the chair. The subject chosen was, "On the Scientific Uses of the Imagination." On entering the hall and taking his place on the platform Professor Tyndall was warmly welcomed, as was also the learned President of the Association.

Mr. Johnson proposed the health of Mr. Strachan ON THE SCIENTIFIC USE OF THE IMAGIin a very eulogistic way, saying that they would have to draw upon the generosity of their guest so far as to ask him to accept the little present which he was about to hand him without the slightest idea that they thought it even shadowed what should be called remuneration for his great services. The subscribers to the testimonial merely desired to tender it to him to show him that he did not serve a totally ungrateful constituency. They had so high an appreciation of the labours Mr. Strachan had bestowed upon the Horological Institute and its journal that it was a lively satisfaction for him to be the medium of presenting a slight testimonial to him. With regard to the production itself they hoped he would look upon it with affectionate regard as an exponent of their feelings towards him, while they themselves looked upon it as but a slight manifestation of those feelings. They felt that he could only be adequately remunerated for his services by a proper salary. He, however, was content to give them his time, talent, ability, and thought for the furtherance of the science of horology. He was not a practical horologist, yet he could find time from the mere love of science to superintend a journal, for the editing of which the Horological Institute was too poor to pay. It was to be hoped that he experienced some of those rewards which virtue was supposed to confer on its votaries. The watch of which he was about to become the recipient had not only engaged the council of the institute in its production, but he saw around him many friends who had been delighted to put into it their workmanship and materials. To name any one gentleman would hardly be right. If the institute was not supported at present as it

The President (Professor Huxley) then said :It is the custom of this association that the president should say a few words in the shape of introduction of the distinguished men who are good enough to take upon themselves the part of lecturers to the association. In the present case, happily for me, the task is one of the slightest character. The lecturer of the evening is known to you, not only by his name but by his works, and not only to you, but wherever this English language of ours is spoken; and I cannot do better than make as brief as possible the interval which separates your expectation of him from your actual acquaintance with his bodily presence by cutting my speech short at this point, and simply announcing to you that Professor Tyndall will now proceed to lecture.

Professor Tyndall thon delivered his discourse. He commenced by remarking that he carried with him to the Alps, this year, the heavy burden of the evening's work. In the way of new investigation he had nothing complete enough to be brought

The

which was demonstrated by the nobleness of the
men whom it sustained. Modern scientific thought
was called upon to decide between this hypothesis
and another; and public thought would generally
afterwards be called upon to do the same.
hypothesis just sketched, however, could never
be stormed, and it was sure, if it yielded at all, to
yield to a prolonged siege. But the process must
be slow and secular which commends the rival
hypothesis of natural evolution to the public mind.
Spirit and matter had ever been presented to us
in the rudest contrast-the one as all noble, the
other as all vile. But was this correct? Did it
represent what our mightiest spiritual teachers
would call the eternal fact of the universe? Upon
the answer to that question all depended. He did
not think that this evolution hypothesis was to be
flouted away contemptuously; he did not think it
was to be denounced as wicked. It was to be
brought before the bar of disciplined reason, and
"Two things,"
there justified or condemned.
"fill me with awe: the
said Immanuel Kant,
starry heavens and the sense of moral responsi-
And in his hours of health and
bility in man."
strength and sanity (Professor Tyndall said in con-
clusion), when the stroke of action has ceased and
the pause of reflection has set in, the scientific
investigator finds himself overshadowed by the
same awe. Breaking contact with the hampering
details of earth it associates him with a power
which gives fulness and tone to his existence, but
which he can neither analyse nor comprehend.

duced

before them, so that all that remained to him was of small particles on the waves of ether. What to fall back upon such residues as he could find in artists called "chill" was, no doubt, an effect of the depths of consciousness, and out of them to spin this description. Through the action of minute the fibre and weave the web of his discourse. For particles, the browns of a picture often present the a time, Mr. Alexander Bain's work on "Logic appearances of the bloom of a plum; by rubbing the became his principal companion, and it interested varnish with a silk handkerchief, optical continuity him most when it became the mirror of his own was established, and the chill disappeared. In condition. Neither intellectually nor socially was the atmosphere we had particles which defy both it good for man to be alone, and the griefs of the microscope and the balance, which do not thought were more patiently borne when we found darken the air, and which exist nevertheless in that they had been experienced by another. multitudes sufficient to reduce to insignificance Speaking of the ebb of intellectual force, which we the Israelitish hyperbole regarding the sands upon all from time to time experienced, Mr. Bain had the seashore. The president, whom untoward said:"The uncertainty where to look for the circumstances had made a biologist, would excuse next opening of discovery brought the pain of con- him to his brethren, if he said that some of them flict and the debility of indecision." Such was his seem to form an inadequate estimate of the dis(Professor Tyndall's) condition in the Alps, and it tance which separates the microscopic from the was under those evil circumstances that he had to molecular limit, and that as a consequence they equip himself for the hour and the ordeal that had sometimes employ a phraseology which is calcunow come. He wished if possible to take them behind lated to mislead. When, for example, the contents the drop-scene of the senses, and to show them of a cell were described as perfectly homogeneous, the hidden mechanism of optical action. It was as absolutely structureless because the microscope possible to uncover, to some extent, the unseen failed to distinguish any structure, then he thought things of nature, and thus to give, not only to pro- the microscope began to play a mischievous part. fessed students, but to others with the necessary Had the diamond, the amethyst, and the countless bias, industry, and capacity, an intelligent interest other crystals formed in the laboratories of in the operations of science. How were those nature and of man no structure? Assuredly they hidden things to be revealed? Bounded and con- bad; but what could the microscope make of it? ditioned by co-operant reason, imagination became Nothing. It was plain that beyond the present the mightiest instrument of the physical discoverer. outposts of microscopic inquiry lay an immense The outgoings of the imagination were guided and field for the exercise of the imagination. It was controlled by the known analogies of science; only, however, the privileged spirits who knew without this power our knowledge of nature would how to use their liberty without abusing it, who be a mere tabulation of co-existences and were able to surround imagination by the firm NAVAL ARCHITECTURE. sequences. Scientific men had made use of this frontiers of reason, that were likely to work with PROFESSOR RANKINE also read an address at the power of imagination in relation to the disturb- any profit here. In more senses than one, Mr. same Hall on naval architecture, taking as the ances caused by the falling of heavy rain-drops Darwin had drawn heavily upon the scientific title of the subject "Stream Lines and Waves in into a tranquil pond; to the vibrations of tolerance of his age; he had drawn heavily upon connection with Naval Architecture." The chairthe air, both in harmony and discord; in time in his development of species, and adven-man, Professor Huxley, in very brief terms, intromastering the cause and mechanism of sound, turously upon matter in his theory of pangenesis. in their desire to know the cause and mechanism From the examination of the solar system, Kant Professor Rankine, who stated that his object of light. In accounting for the colour of the sky, and Laplace came to the conclusion that its various was to give a brief summary of the results of some the first question suggested by analogy would un- bodies once formed parts of the same undislocated applications of the mathematical theory of hydrodoubtedly be-Is not the air blue? The blueness mass; that matter in a nebulous form preceded dynamics to questions relating to the designing of the air had in fact been given as a solution of matter in a dense form; that, as the ages rolled of the forms of ships, and to the mutual actions the blueness of the sky. But reason, basing itself away, heat was wasted, condensation followed, between a ship and the water in which she floats. on observation, asked in reply-How, if the air be planets were detached, and that finally the chief The art of designing the figures of ships had been blue, can the light of sunrise and sunset, which portion of the fiery cloud reached, by self-compres- gradually developed by processes resembling those travels through vast distances of air, be yellow, sion, the magnitude and destiny of our sun. The called "natural selection and the " struggle for orange, or even red? The passage of the white earth itself offered evidence of a fiery origin; and existence," in the course of thousands of years, solar light through a blue medium could by no in our day the hypothesis of Kant and Laplace re- and had arrived in skilful hands at a perfection possibility redden the light. The hypothesis of a ceived the independent countenance of spectrum which left little more to be desired, when the obblue air was therefore untenable. In fact, the agent, analysis, which proved the same substances to be ject was to design a ship that should answer purwhatever it was, that sent us the light of the sky common to the earth and the sun. Accepting poses and fulfil conditions which had previously exercised in so doing a dichroitic action. The some such view of the construction of our system been accomplished and fulfilled in the course of light reflected was blue, the light transmitted was as probable, a desire immediately arose to connect practical experience. But cases now frequently orange or red. By the force of imagination and the present life of our planet with the past. We arose in which new conditions were to be fulfilled, reason combined we might penetrate this mystery. wished to know something of our remotest ancestry. and purposes accomplished beyond the limits of Were reflecting foreign particles small in compa- On its first detachment from the central mass, life, the performance of previous vessels; and in such rison to the size of ether waves sown in our at- as we understood it, could hardly have been pre- cases the process of gradual development by pracmosphere, the light scattered by those particles sent on the earth. How, then, did it come there? tical trials made without the help of science was would be exactly such as we observe in our azure The thing to be encouraged here was a reverent too slow and too costly; and it became necessary skies. When this light was analysed all the colours freedom-a freedom preceded by the hard disci-to acquire and to apply scientific knowledge of the of the spectrum were found. The white light pline which checks licentiousness in speculation laws that regulate the actions of the vessel on the which passed unscattered among the particles, by-while the thing to be repressed, both in science water and of the water on the vessel. Amongst its successive collisions with the particles, was and out of it, was dogmatism. Clergymen had as the questions thus arising were the following:— more and more robbed of its shorter waves; it strong a leaning towards scientific truth as other What ought to be the form of the immersed surtherefore lost more and more of its due proportion men, only the resistance to this bent-a resistance face or skin of a ship in order that the particles of of blue. The result might be anticipated. The due to education-was generally stronger in their water may glide smoothly over it? And the form transmitted light, where short distances were in case than in others; they did not lack the positive of such a surface being given, how will it affect volved, would appear yellowish. But as the sun element, namely, the love of truth, but the the motions of particles in its neighbourhood, and sank towards the horizon the atmospheric dis- negative element, the fear of error, prepon- what mutual forces will be exerted between the tances increased, and consequently the number of derated. Did the introduction of life belong to particles of water and that surface? Practical exthe scattering particles. They abstracted in suc- what we called matter; or was it an independent perience, unaided by science, answers the first cession the violet, the indigo, the blue, and even principle inserted into matter at some suitable question by saying that the surface ought to belong disturbed the proportions of green. The trans- epoch? There were the strongest grounds for to a class called "fair surfaces "-(that is surfaces mitted light under such circumstances must pass believing that during a certain period of its his- free from sudden changes of direction and of curfrom yellow through orange to red. This was tory the earth was not, nor was it fit to be, the vature) of which various forms have in the course exactly what we found in nature; thus, while the theatre of life. Whether this was ever a nebulous of ages been ascertained by trial, and are known reflected light gave us at noon the deep azure of period, or merely a molten period, did not much to skilful shipbuilders. That answer is satisfactory, the Alpine skies, the transmitted light gave us matter; and if we reverted to the nebulous condi- so far as it goes; bnt in order to solve problems at sunset the warm crimson of the Alpine tion it was because the probabilities are really on involving the mutual actions of the ship and the snows. Could small particles be really proved its side. Did creative energy pause until the water, something more is wanted; and it becomes to act in the manner indicated? No doubt of it. nebulous matter had condensed, until the earth necessary to be able to construct fair surfaces by Professor Brucke had shown us how to obtain a had been detached, until the solar fire had so geometrical rules based on the laws of the motion blue medium by dissolving resin in spirit. A trace far withdrawn from the earth's vicinity as to per- of fluids, and to express their forms by algebraic of soap in water gave a tint in blue. London, and mit a crust to gather round the planet? Did it equations. There were many very early attempts he feared Liverpool milk, made an approximation wait until the air was isolated, until the seas were to do this; but, not being based on the laws of hyto the same colour through the operation of the formed, until evaporation, condensation, and the drodynamics, they resulted merely in the finding same cause; and Helmholtz had irreverently dis- descent of rain had begun, until the eroding forces of empirical rules for reproducing when required closed the fact that a blue eye is simply a of the atmosphere had weathered and decomposed forms that had previously been found to answer in turbid medium. The action of turbid media the molten rocks so as to form soils, until the practice, and did not lead to any knowledge of the upon light was fully and beautifully illustrated sun's rays had become so tempered by distance motions of the particles of water or of the forces by Goethe, who, though unacquainted with the and by waste as to be chemically fit for the de- exerted by and upon them; and they had little or undulatory theory, was led by his experiments to compositions necessary to vegetable life? Having no advantage over the old process of modelling by regard the blue of the firmament as caused by an waited through those Eons until the proper con- the eye and hand, and of "fairing" the lines with illuminated turbid medium with the darkness of ditions had set in, did it send the fiat forth, "Let the help of an elastic rod called a "batten." As space behind it. Professor Stokes was probably life be?" These questions defined a hypothesis regards this process, indeed, the mathematical the first to discern the real nature of the action not without its difficulties, but the dignity of methods about to be referred to were to be regarded,

not as a substitute for it in designing the form of a gitudinal lines of a ship three sets at least of com- regarding these phenomena was, that when the ship, but as a means of arriving at a knowledge of ponent stream-lines must be combined. One of speed of the vessel was less than, or equal to the the mutual actions between her and the water, these is a set of parallel straight lines, represent- natural speed of the waves raised by her, the rewhich the old process is incapable of affording. ing an uniform current running astern with a sistance of the vessel consisted wholly, or almost The earliest method of constructing the figures of speed equal to the actual speed of the vessel. A wholly, of that arising from the friction of the ships by mathematical rules based on hydrody-second set consists of straight lines radiating from water gliding over her skin; and he considered namical principles was that proposed by Mr. Scott a point called a focus in the fore part of the vessel, that this opinion was confirmed by the results of Russell about twenty-five years ago, and since very and they represent the diverging motion that is practical experience of the performance of vessels. extensively practised. It consisted in adopting for produced by the ship displacing the water near The wave-motion, being impressed once for all on the longitudinal lines of a ship curves imitated her bows. The third set of component stream-the water during the starting of the vessel, was from the outlines of waves in water. The motions lines consists of straight lines converging towards propagated onward like the swell of the ocean, which surfaces formed upon this model impressed a second focus in the after part of the vessel, and from one mass of water to another, requiring on the water are known to a certain degree of they represent the motion of the water closing in little or no expenditure of motive power to keep approximation. Those "wave-lines," however, astern of the ship. The resultant stream-lines it up. But, when the ship was driven at a speed although they were fair curves in the sense already thus produced present a great variety of forms, all exceeding the natural speed of the waves that she mentioned, were by no means the only fair curves, resembling those of actual ships, having all possi- raised, those waves, in order to accompany the but were only one class out of innumerable classes ble proportions of length to breadth, and all de- ship, were compelled to spread obliquely outwards of curves having the property of gliding smoothly grees of bluffness and fineness at the ends, ranging instead of travelling directly ahead; and it became through the water; and it was well known in from the absolute bluffness of a sort of oval to a necessary for the vessel, at the expense of her practice that vessels had proved successful whese bow and stern of any degree of sharpness that may motive power, to keep continually originating lines differed very widely from wave-lines. It be required. It has been proposed to call stream-wave motion afresh in previously undisturbed was, therefore, desirable that methods should be lines of this sort Oogenous Neoids, that is, ship- masses of water; and hence the waste of power devised of constructing by mathematical rules, like lines generated from an oval, because any found by experience to occur when a ship was based on the laws of the motion of fluids, a great given set of them can be generated by the flow of driven at a speed beyond the limit suited to her variety of curves possessing the requisite property a current of water past an oval solid of suitable length. This divergence, or spreading sideways of fairness, and not limited to the wave-line shape. dimensions. The properties of these curves were of the train of waves, had a modifying effect on Such had been the object of a series of researches investigated in 1862. They have, however, this the stream-lines representing the motions of the that had been communicated to the Royal defect, that the absolutely bluff ovals are the only particles of water. It caused them, in the first Society at different dates since 1862. They curves of the kind that are of finite extent; all the place, to assume a serpentine form; and then, related to the construction of what it has been finer curves extend indefinitely in both directions instead of closing in behind the ship to the same proposed to call stream-lines. A stream-line is the ahead and astern, and in order to imitate the distances from her course at which they had been track or path traced by a particle of water moving longitudinal lines of a fine-ended vessel a part situated when ahead of her, they remained in a smoothly and steadily flowing current. If, only of some indefinitely extended curve must be permanently spread outwards. In other words, the when a ship is gliding ahead through the water taken. In 1870 an improvement in the con- particles of water did not return to their original with a certain speed, we imagine the ship to be struction of such curves was made, by which distance from the longitudinal midship plane of the stationary, and the water to be flowing astern past that defect was overcome; it consisted in the vessel, but were shifted laterally and left there, the ship in a smooth and steady current with an introduction of one or more additional pairs of much as the sods of earth are permanently shifted equal average speed, the motions of the ship and foci, involving the combination of at least five sideways by the plough. The place of the water of the particles of water relatively to each other sets of component stream-lines. By this device it which thus fails to close in completely astern of are not altered by that supposition; and it becomes is possible to imitate the longitudinal lines of the vessel is supplied by water which rises up from evident that if the form of surface of the skin of actual vessels by means of complete closed below, and forms a mass of eddies rolling in the the ship has the property of fairness, all the tracks curves without using portions of indefinitely ex- wake of the ship. This was illustrated by a diaof the particles of water as they glide over that tended curves; and thus the knowledge of the gram. Lastly, the lecturer explained the prinsurface are stream lines, and the surface itself is motion of the particles of water, as shown by the ciples according to which the steadiness of a ship one containing an indefinite number of stream stream-lines that lie outside the closed lines re- at sea is affected by waves; and the difference belines; or, as it has been called, a stream-line sur- presenting the form of the vessel, becomes more tween the properties of steadiness and stiffness. face. It is also to be observed that when we have definite and accurate. The lecturer mentioned The mathematical theory of the steadiness of ships deduced from the laws of the motion of fluids the that the idea of employing four foci and upwards had been known and applied with useful results for relations which exist between the forms of the had been suggested to him by the experiments of nearly a century; but in the course of the last few stream-lines in different parts of one current, and Mr. Froude on the resistance of boats modelled so as years it had recived some important additions, due between those forms and the velocities of the to resemble the form of a swimming bird, for which especially to the researches of Mr. Froude on the particles as they glide along different parts of purpose stream-lines with four foci are specially manner in which the motions of the waves affect those lines, we know the relation between the adapted. It has been proposed to call such lines the rolling of the vessel. A stiff ship is one that form and speed of a ship whose surface coincides Cycnogenous Neoids; that is, ship-like curves of tends strongly to keep and recover her position of with a certain set of those stream-lines, and the shapes like that of a swan. In such curves, when uprightness to the surface of the water. A steady motions of the particles of water in various posi- adapted to fine-ended ships, the outer foci-that ship is one that tends to keep a position of tions in the neighbourhood of that ship. The is, the foremost and the aftermost, are situated in or absolute uprightness. In smooth water these prolecturer then proceeded to explain and to illus-near the stem and sternpost of the vessel, which are perties are the same; a stiff ship is also a steady trate by diagrams the methods of constructing represented in plan by small horse-shoe-like curves, ship in smooth water. Amongst waves, on the stream-lines These methods were based upon as if they were rounded off at the corners, instead other hand, the properties of stiffness and steadithe application to stream-lines in a current of of being square, as in ordinary practice. The inner ness were often opposed to each other. A stiff fluid, of a mathematical process which had previ- foci are situated respectively in the fore and after ship tends as she rolls to follow the motions of the ously been applied by Mr. Clerk Maxwell to lines body. When the foci of the longitudinal lines of waves as they roll; she is a dry ship; but she may of electric and magnetic force. A current of fluid a vessel have been determined, the proportion be what is called uneasy through excessive rolling is represented on paper by drawing a set of stream-borne by the aggregate energy of the motion im along with the waves. The property of stiffness lines, so distributed that between each pair of pressed on the particles of the water to that of the is possessed in the highest degree by a raft, and them there lies an elementary stream of a given motion of the vessel herself, can be approximately by a ship which, like a raft, is very broad and constant volume of flow. Thus, while the direc- determined. The lecturer next proceeded to explain shallow, and whose natural period of rolling in tion of flow is indicated in any given part of the the bearing of some of the mechanical properties smooth water is very short compared with the current by the direction of the stream-lines, the of waves upon the designing of vessels, especially periodic time of the waves. In order that a ship velocity of flow is indicated by their comparative when these properties are taken in combination may be steady amongst waves, her natural period closeness and wideness apart, being evidently with those of stream-lincs. It had long been known of rolling should be considerably larger than that greatest where those lines lie closest together, and that ships in moving through the water were of the waves, and in order that this property may least where they are most widely spread. If, accompanied by trains of waves, whose dimensions be obtained without making the vessel crank, the upon the same sheet of paper, we draw two dif- and position depended upon the speed of the masses on board of her should be spread out sideferent sets of stream-lines, these will represent vessel; but the first discovery of precise and defi- ways as far as practicable from the centre of the currents produced in one and the same mass nite laws respecting such waves was due to Mr. gravity; this is called "winging out the weights." of fluid by two different sets of forces. The two Scott Russell, who published it about twenty-five A vessel whose natural period of rolling in smooth sets of lines represent a network; and if, through years ago. The lecturer next described, in a water is only a little shorter or a little longer than the angles of the meshes of that network we draw general way, the motions of the particles of water that of the waves has neither the advantages of a third set of stream-lines, it can be proved from the in a series of waves, and illustrated them by stiffness nor those of steadiness; for she rolls to an principle of the composition of motions that this means of a machine contrived for that purpose. He angle greater than that of the slope of the waves, third set of lines will represent the current pro- showed how, while the shape of the wave advances, and her condition is specially unsafe if her duced in the same mass of fluid by the combination each individual particle of water describes an orbit natural period of rolling is a little greater than of the forces which, acting separately, would produce of limited extent in a vertical plane. The that of the waves; for then she tends to heel over the currents represented by the first two sets of periodic time of a wave, its length, the depth to towards the nearest wave crest, to the danger of stream-lines respectively. The third set may be which a disturbance bearing a given ratio to the its breaking inboard. This is called "rolling called the resultant stream-lines, and the first two the disturbance at the surface of the water extends, against the waves.' The most dangerous concomponent stream-lines. Suppose, now, that a and the speed of advance of the wave, are all dition is that of a vessel whose period of rolling in third set of component stream-lines are drawn, related to each other by laws which the lecturer smooth water is equal to that of the waves that representing the current produced by a third set explained. He then stated that Mr. Scott Russell she encounters; for then every successive wave of forces, this will form a network with the pre- had shown that, when the vessel moved no faster makes her roll through a greater and greater viously drawn resultant stream-lines, and a set of than the natural speed of advance of the waves angle, and under these circumstances no ship can lines drawn through the angles of the meshes of that she raised, those waves were of moderate be safe, how great soever her stability. All these this new network will represent the resultant cur- height, and added little or nothing to her resist-principles have been known for some years, rent produced by the combination of the three sets ance, but, when that limit of speed was exceeded, through Mr. Froude's researches. The lecturer of forces; and so on to combinations of any degree the waves, and the resistance caused by them, in- exhibited a machine which he had contrived for of complexity that may be required. In order to creased rapidly in magnitude with increase of illustrating them, in which the dynamical condidraw a system of stream-lines suited for the lon- speed. His own (Professor Rankine's) opinion tions of vessels of different degrees of stiffness and