and sere,


The day draws in ; the mists of eve wax

chilly, When first the Nymph of Summer woke to

And fainter grow her footsteps and more pleasure

faint, The birds sang shrill and sweet in leafy

The graceful head droops like a faded lily bowers ;

Hung from the dead hand of a virgin Before her feet June shed her fairest treas

saint. And gemmed the untrodden grass with Night falls. An owl hoots from the fir

tree cover, nodding flowers.

A breeze sighs through the rushes dried By some lone fount, in forest dell secluded, Where thick ferns hung their tresses in and autumn clouds hang their dank tresses the stream,

over All the hot summer days she sat and

The Nymph of Summer on her lonely brooded

bier. Over sweet memories of a happy dream.


Longman's Magazine.
Men in the tangled forest glades benighted,
When the bright moon had hushed the

restless breeze,
Heard, with dazed mind and every sense

THE SPRING-TIDE COMES. Clear as a bell, her voice rise through the

THE Spring-tide comes along the way, trees.

And from her 'broidered kirtle gay The Nymph of Summer's song, serene and

She scatters daisies o'er the hills ; splendid,

Gold dust falls from the daffodils Cleaving the silence like an angel's wing, That crown her head on fell and brae. Rose glorious through the night, and fitly Her breath woos bloom on bough and ended

spray ; The slowly fading melodies of spring.

Bright the marsh-flower's golden ray,

When by the softly singing rills So summer sped. Sun unto sun succeed

The Spring-tide comes. ing Moved in a fair procession past her gaze, Till sadness seized her soul, as surely read- The young lambs round her footsteps play

The tassels on the larches sway ; ing

The blackbird's song the valley fills ; The fated end of all her pleasant days.

Above her head the skylark trills ; She saw the darkness wax, the daylight

The thrushes lilt a roundelay, waning,

The Spring-tide comes. Poor lovely child of summer and the sun !

Chambers' Journal. MAGDALEN ROCK. Each flower that withered, mute and un

complaining, Told that her days of life were nearly



SONNET. She feels Death touch her brow with icy finger,

For her gait if she be walking, And shrinks before him as the blossoms Be she sitting I desire her shrink ;

For her state's sake, and admire her She rises slow, no longer may she linger For her wit if she be talking : Beside her charmed fountain's mossy Gait and state and wit approve her ; brink ;

For which all and each I love her. But, wandering down the glades, ere death o'ercome her,

Be she sullen, I commend her Hears, through the silence of the autumn For a modest ; be she merry days,

For a kind one her prefer I ;
The sad-voiced robins singing out the sum- Briefly, everything doth lend her

So much grace and so approve her, And dead leaves falling thick in wood- That for everything I love her.




land ways.

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From The Edinburgh Review. observation. No criterion was, howTHE LIQUEFACTION OF GASES.1

ever, at hand by which to decide THE “ third state ” of matter was whether, in so doing, it constituted an formally recognized by Van Helmont, exception or followed a rule. Indeed, a Belgian alchemist, early in the seven- we are still ignorant of any abstract teenth century. But his discovery principle bearing on the subject.

. might have slipped back into oblivion Thus, apart from actual experience, bad he not emphasized it by the inven- there could be no well-grounded assurtion of a name. The unseen and un-ance that the behavior of water would felt, yet material, substances brought prove typical. Under altered condiinto notice by his researches were lions it even departs from its own called by him “ gases,

and are called standard. In a partial vacuum ice so still. Atmospheric air was not in- cannot be melted. When heated above cluded among them. For it ranked in freezing-point, in a vessel exhausted those days as an element in the of air to a certain degree, it passes Aristotelian sense. Boyle, however, directly into vapor. On a planet, in became aware of its composite charac- fact, possessing an atmosphere ter, though he failed to isolate the hundred and sixty-five times rarer than " vital

ingredient, the existence and our own, liquid water could not exist. functions of which he divined. It was Whether placed as near to the sun as not, indeed, until more than a cen- Mercury, or as far from him as Neptury later that oxygen was definitively tune, such a globe could show neither captured by Priestley and Scheele. seas nor streams. No rain could fall Carbonic acid, meanwhile, had been there, no dew be deposited ; aqueous investigated by Black;

by Black; Cavendish condensations would invariably take gave, in 1766, the earliest description of the form of snow. Sublunary experi

inflammable air,” alias hydrogen ; ence, too, makes us acquainted with and nitrogen was made known by many complex substances which cannot Priestley in 1772. Then Lavoisier, ex- change their state, because the applicatricating these valuable discoveries tion of heat very quickly tears their from the misapprehensions in which innermost structure to pieces. Who, they lay involved, and bringing them for instance, would attempt to melt into logical connection with the results wood or leather ? The very idea seems of his own inquiries, shaped the new absurd, because every one knows that science of pneumatic chemistry. they char or burn while still solid.

Matter in general was thenceforward That is to say, they cease to be, as systematically studied under its solid, wood or leather, long before their liquid, and gaseous forms. But there respective ideal fusivg-points was as yet no certainty that every indi- reached. Elementary bodies cannot, ridual kind of matter was capable of of course, be decomposed ; but some assuming each in turn. One example resist liquefaction, if not absolutely,

. of this versatility had, it is true, been at yet at least so far as to sublime without all times familiar, Water undergoes melting, like ice in a vacuum. One of its cycle of changes from ice to steam these is arsenic. And carbon volatilnaturally, and as a matter of common izes only at an enormously high tem

11. The Chemical Work of Faraday in relation perature, and has never been liquefied. to Modern Science. Lecture delivered at the possibly the intermediate state might Royal Institution, June 26, 1891. By Professor

be forced

upon it by accompanying Dewar, M.A., F.R.S.

2. Magnetic Properties of Liquid Oxygen. Lec- great heat with high pressure ; but the ture delivered at the Royal Institution, June 2, idiosyncracies of chemically distinct 1992. By Professor Dewar, M.A., F.R.S. 3. Liquid Atmospheric Air.

substances are so peculiar that its reat the Royal Institution, January 20, 1893. By luctance may represent real inability to Professor Dewar, M.A. Y.R.S.

liquefy. 4. The Scientific Uses of Liquid Air. delivered at the Royal Institution, January 19,

The law, however, of Ube three states 1894. By Professor Dewar, M.A., F.R.S.

of matter is most probably universally


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Lecture delivered


valid both for simple bodies and for | influences of licat, light, electricity, or stable compounds. The power by chemical affinity ; but the operation is which it is enforced resides in heat. destructive of the body originally conNear the bottom of the scale of tem- posed by them, and the new ones by perature, solidificatiou reigns supreme ; which it is replaced are often wholly towards the opposite extreme, vapor- diverse from it in their qualities and ization. The moon exemplifies the relationships. Thus, each of the ultifirst condition, the sun the second. mate particles of water consists of at Between the two stands our earth, in least three unimaginably minute porwhich solids, liquids, and gases co- tions — two of hydrogen and one of exist. It is composed, in other words, oxygen — the separation of wbich inof the three antique "elements," volves the demolition of water and the earth, water, and air. Now, the fact substitution for it of its gaseous conthat, under the same circumstances, stituents. Conversely, oxygen is condifferent substances are differently ag- verted into ozone when its molecules gregated is none the less remarkable are compelled, through the action of for being tritely familiar. It seems a electricity, to annex each a third atom matter of course that our atinosphere of the stuff itself. Yet ozone, though should, at all times and seasons, remain nothing but oxygen chemically conimperturbably ethereal — that rigid densed, possesses highly characteristic rocks should enclose a heaving ocean, qualities of its own. and that mercury, alone among metals,

Molecular structure, then, and the should flow like water. And it is easy forces of which the niodes of action are to see that the prevalence of such like modified by it, determine the properincongruities is essential to the scheme ties of matter. A molecule is a subof things to which we ourselves belong. microscopic piece of mechanism of Unanimity among the various kinds of exquisite flexibility, conjoined, in many matter in freezing, melting, and boil- cases, with a high degree of stability. ing, would obviously exclude the possi- An organic whole, complete in itself, it bility of life. The question, then, why is nevertheless sensitive to manifold it is excluded, answers itself; but if influences from without. It is all alive we go on to ask how it is excluded, we with energy in the shape of motion, the meet with no truly articulate response. motive power being supplied by heat. All that can be said is that the ob- Apart from this stimulus it would be as served wide diversities of melting and inert as a locomotive with the steam boiling points result from an equally shut off. Matter in this state of hiberwide diversity in the conditions affect- nation, however, lies outside the scope ing the molecular equilibrium of the of terrestrial experience. Even at the substances severally concerned. As an lowest temperatures attainable by artiexplanation this is evidently unsatis- ficial contrivances, its particles thrill factory. It amounts to little more than with varied movements, which, as they a restatement of the same fact in differ- gain intensity through increase of heat, ent words. Yet the difference of word- tend to separate the molecules in oppoing is instructive ; it implies a good sition to the cohesive force drawing deal. Let us consider and draw out its them together. Cohesion acts with meaning

enormous power, but over a narrowly The word "molecule” – equivalent limited range. M. Quincke calculates to little mass — was employed in 1811 that the mutual attraction of two wolby an Italian physicist named Avoga- ecules is insensible at distances exdro, to designate the smallest particles ceeding one twenty-thousandth of a of any substance - solid, liquid, or millimetre ;? yet within that minute gaseous - in which its distinctive qual- interval its action is of amazing vigor. ities are preserved in their integrity. The irresistible energy of leat can, Molecules are not indivisible. They can be severed into 66 16 atoms


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1 Glazebrook, Properties of Matter, p. 119,

by the

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it is true, unlock the grip of the belongs to heat. Thermal energy immolecules ; but only when lavishly parts the movements by which cohesion expended. The force consumed in is overcome. There is no substance so melting one pound of ice would suffice, obdurate but that it gives way before if mechanically applied, to lift it about the persistent attacks of the "drudging lwenty-one miles from the ground; goblin” of our laboratories. Even and the vaporization of the resulting platinum volatilizes in the electric arc pound of water would be a piece of at a temperature of about 4500° of work nearly seven times more arduous Fahrenheit. Intense cold, however, is again. Yet the large stores of heat much more difficult of production than thus employed in overcoming cohesive intense heat. And only by means of bonds produce no thermometric effects. extraordinarily intense cold can truly They remain “latent” in the bodies aëriform substances be brought to subthey serve to modify, and are given mit to the yoke of internal attractions. out again in undiminished quantity Nor can they be mechanically comduring the inverse processes of lique- pelled to do so. Pressures up to twenty faction and solidification.

tons per square inch were, by Natterer, The differences betweeu solid, liquid, in 1853, brought to bear upon large and gaseous bodies depend mainly upon volumes of hydrogen, oxygen, and nichanges in the relative mobility of their trogen, without the slightest effect in ultimate particles. These little sys- changing their state ; and air has been tems, which are crowded by quadril- quite fruitlessly, so far as liquefaction lions into every cubic inch of matter, was concerned, condensed until beayare in all cases animated by movements ier, bulk for bulk, than water.1 Therof vibration, perhaps also of rotation mal activity must, in fact, be reduced and even of orbital circulation ; but below a certain definite point before under the strict rule of solidity they lle passage of a gas into a liquid bepossess no proper motions; each has comes possible. This general principle its own place and keeps it. Liquefac- was recoguized by Faraday in 1826, but tion, however, confers a translatory its detailed development by Andrews faculty. The molecules of fluids travel in 1869 constituted a fresh discovery of indefatigably. Let any one who doubts the highest importance. He showed this to be a fact introduce a few drops that above a certain fixed temperature, of some colored tincture into a glass of proper to each, aëriform Nuids caunot water, and observe, after a time, the assume the liquid state. Many of these equable diffusion of the tint. He will " critical temperatures were deterno longer hesitate to admit the prog- mined by him. That of carbonic acid, ress of incessant, undirected intersti- for instance, he found to be 88° F. tial movements. Yet the qualified Above that point no compulsion avails freedom of liquidity is bondage com- to bring about liquidity ; below it, pared with the unrestricted license of pressure is effectual, and more readily the gaseous state. Here the last link with diminution of heat. In other of cohesive constraint is broken. Each words, this substance is, in the techminutest particle of an aëriform fluid nical sense, a gas when hotter, a vapor is not only virtually independent of the when colder, than 88o. No less than others, but strives towards definite sep-144° of frost are, however, needed to aration from them. Hence a gaseous liquefy it under ordinary atmospheric mass forms of itself no definite surface. pressure. At the sea-level, that is to If distributed in the shape of an atmo- say, carbonic acid boils in open vessels, sphere it may be coerced by gravity. at -112o. Water, as everybody knows, When evolved on the earth's surface it reaches the corresponding stage 324° can be preserved only by being impris- higher, at 212° ; but its boiling point oned; for its inner principle is one of can, by means of continually increased limitless dispersion.

The mastery over the states of matter 1 Barker, Text-Book of Physics, p. 319


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pressure, be pushed up the scale as far | furnishing the pressure to which these as 773°. Red-hot water is thus a pos- results were due. The assistance of sibility ; although in approaching, eveu cold was not invoked ; aud, indeed, the distantly, the critical temperature above difficult art of refrigeration was then in which it cau only subsist as a gas, it its infancy. Its wonderful progress in becomes dangerously explosive. Vol- recent times may be said to date from canic outbursts are often, it is believed, Thilorier's production, in 1835, of solid immediately due to the sudden flashing carbonic acid. “ Snow" of this peculinto steam of superheated water. iar description might, so far as appear

The critical temperatures of the va- ances go, have come from an Alpine rious kinds of matter extend over a nevé. Although cold enough to give a wider range than has yet been thermo- severe burn, it can be lightly handled metrically explored. Those of some of with impunity, and is tolerably permathe metals, as well as of carbon and nent even in warm air. Mixed with silicon, must represent an enormous ether, it enabled Faraday to resume in degree of heat; those of several gases 1844 his efforts towards condensation have been ascertained to verge towards with the aid of temperatures as low as the lowest limit of cold. Their several –166° F. Six gases, nevertheless, positions depend upon the way in which continued to hold their own. The the balance, in each particular case, in- chief of these were hydrogen, oxygen, clines between the antagonistic forces and nitrogen ; but the resistance of all of heat and cohesion. For, however except hydrogen has since been overclosely the particles of a body may be come. constrained to approach each other, The liquefaction of oxygen by two they will not cohere while in extra independent investigators, Pictet of rapid motion. This doctrine is of Geneva, and Cailletet of Paris, was grave significance to physical theory ; announced to the French Academy of and the guidance afforded by it is indis- Sciences on the same day of December, pensable to the success of practical re- 1877.2 Unknown to each other they searches into the transformations of had been working for several years matter.

along parallel lines.

Their success Lavoisier divined the not too obvious was, indeed, determined by the use of truth that the “ state ” of any material an identical method. The gas, loaded substance is a mere question of temper- with the weight of five or six hunature, and that consequently the so- dred atmospheres at a temperature of called "

permanent” gases might, by about —130° F., was then suddenly extreme cold, be reduced liquids, and allowed to escape through a these again to solids. And Dalton aperture. The ensuing violent expanwrote, in 1801 : “ There can scarcely sion consumed a large quantity of beat, be a doubt entertained respecting the the abstraction of which froin an adjareducibility of all elastic fluids, of what- cent portion of the same substance ever kind, into liquids; and we ought cooled it to the point of condensation, not to despair of effecting it in low and liquid oxygen was for the first time temperatures, and by strong pressure seen on our planet. But only in a thin exerted upon the unmixed gases.” 1 jet and during a few seconds. Its cap

The experimental verification of this ture for examination was out of the forecast, vow all but complete, was question. begun by Faraday. In 1823 he an- More tangible results were obtained nounced the liquefaction of chlorine ; in 1883 by the Russian chemists and he was similarly successful with Wroblewski and Olszewski.

Their carbonic acid, nitrous oxide, cyanogen, liquid oxygen was no mere momentary ammonia, and some other gases, their vision, but submitted to rule and meascontinued evolution in closed vessels ure in a capillary tube. Its qualities

1 Quoted by Dewar, Proceedings Royal Institution, vol. viii., p. 657.

? Comptes Rendus, t. lxxxv., pp. 1214, 1217.


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