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by carbonic acid gas escaping through the dough, making it light and porous. It is furnished for this process either by fermentation produced by yeast added to the dough, or by baking-powder from which it is set free by the moisture of the dough to which the powder has been added.

Like air the gas can be liquefied by cold and pressure. At 60° F. a pressure of 800 pounds will reduce it to a liquid. A cubic foot of the gas at this temperature and pressure is reduced to a cubic inch of fluid, the volume being decreased 1728 times.

The lower the temperature the less the pressure required to reduce it to a liquid, the pressure required being in direct proportion to the temperature. The gas thus liquefied is extensively sold in strong metal tubes for charging soda-water fountains, siphon bottles, etc.

When the liquefied carbon dioxide is allowed to evaporate it produces cold just as liquid air does. The cold is not so intense as that produced by liquid air, as it does not evaporate so rapidly, the intensity of the cold produced being greater where evaporation is more rapid.

The pressure

required to liquefy air being greater, and the temperature required lower, the evaporation of liquid air is more rapid, though in both it is instantaneous when the pressure is removed. Liquefied carbon dioxide is found in nature enclosed in quartz, granite, and coal. Carbonic acid gas can be made by pouring sulphuric acid on limestone, marble, or soda, the last being the method used to charge soda fountains when the liquefied gas is not used.

That the diamond and pure charcoal are composed of exactly the same thing carbon is proved by burning them separately in pure oxygen in closed vessels, allowing nothing to escape, the product in both instances being this gas. The greater part of all fuel being carbon, and combustion being the rapid oxidation of a substance, the chief product of combustion is carbon dioxide. When charcoal is burned with a free access of air, carbon dioxide is formed; when the supply of air is not free, carbon monoxide results from incomplete combustion. This carbon monoxide is a gas having active narcotic properties, and is the agent which produces death when illuminating-gas is inhaled, death from this cause being due, not to suffocation, but to the effect of carbon monoxide on the heart, lungs, and nerve

centres. Carbon dioxide, not being a supporter of respiration, produces death by suffocation, as, when breathed, it prevents the access of air. In deaths due to suffocation by carbon dioxide unconsciousness is very rapidly produced. When there is an excess of carbon dioxide in the blood of a person, as frequently happens at hangings when strangulation occurs, it produces, after unconsciousness, violent muscular spasms, the force of which is sometimes so great as to tear the muscles in two. The horrible twitching and contortions so often witnessed at executions are due to these spasms, yet they are painless, as unconsciousness precedes them. The origin of the gas in these cases is in the slow combustion or oxidation which goes on in the body, furnishing it with its normal heat. The oxygen of the air, when inhaled, is carried in the blood of the arteries to the tissues and given up to them; after being converted into carbon dioxide it is carried in the blood of the veins to the lungs and is thence given off in expiration. It is this gas that gives the dark color to the venous blood, which in the lungs is converted into the kind found in the arteries when it gives up this carbon dioxide and takes up oxygen. From the lungs this converted blood is carried back to the heart, to be again distributed to the tissues. The red blood, which is that of the arteries, carries oxygen; the dark or venous blood carries carbon dioxide.

The vitiation of the atmosphere of close and crowded rooms is due to the accumulation of exhaled animal matter and carbon dioxide added to by lamps and gas jets. An addition of more than two or three parts to the existing four parts of carbon dioxide in ten thousand parts of air is regarded as injurious. It is calculated, from the amount of carbon dioxide produced, that one gas jet consumes as much air as sixteen persons. The incandescent light is the only one which consumes no air and produces no carbon dioxide, and for this reason it may be considered the hygienic light.

In cigarette, cigar, and pipe smoking both carbon dioxide and the poisonous carbon monoxide are formed and inhaled with the smoke. It is probable that some of the narcotic and injurious effects of smoking tobacco are due to this monoxide. The monoxide differs from the dioxide in composition in having one part less of

oxygen, it being composed of one part each of carbon and oxygen. When the monoxide is burned it produces the dioxide. The presence of the monoxide in tobacco smoke can be detected by taking a full "draw" and blowing the smoke back through the pipe or cigar upon a lighted match. The gas will then be seen burning with a blue flame.

Accumulations of carbonic acid gas, present from local causes in caves, old wells, and brewers' vats, have frequently been the cause of death to persons entering them without testing for the gas. The test is made by lowering a lighted candle to the bottom of the well, as the gas sinks on account of its weight. If the light is extinguished entrance would be very unsafe. Tramps attracted by the warmth of burning lime-kilns, and sleeping near them, have been found dead from the effect of this gas, given off in the process of burning limestone into lime. The deaths of the prisoners in the "Black Hole" of Calcutta were due to the carbonic acid gas evolved from the prisoners' own bodies by respiration. No fresh air being admitted to the prison the gas accumulated until fatal results were produced.

One of the most practical and effective applications of carbon dioxide is in the chemical fire engine. Here it is the agent which throws the stream and extinguishes the fire. The engine consists of two exactly similar tanks, each holding sixty gallons of water. In this twenty-five pounds of soda is dissolved, an agitator being used to facilitate its solution. the top of each tank there is a bottle containing eleven pounds of sulphuric acid.

In

The bottle is kept tightly closed until it is desired to use the engine, when by turning down the bottle the acid flows into the soda solution. The gas is very rapidly generated when the acid and the soda solution come together, and in a very short time a pressure of three hundred pounds to the square inch can be obtained, which will throw a half inch stream of mingled water and gas about ninety feet. The water is here used rather as a means of conveying the gas than for its own fireextinguishing properties, for the gas liberated from the water by the jar of the impact and by the heat covers the fire, excluding the air much more effectually than water, and thus smothers it. In some cities more than eighty per cent of the fires are extinguished by these chemical engines. Only one tank on the engine is used at a time, so that it can be kept going constantly by recharging the empty tank while the other is used. The method of charging the tank is exactly the same as that used to charge a soda fountain. Any one can demonstrate the feasibility of extinguishing fire by this gas by holding a lighted match close over a freshly drawn glass of soda water, or over a glass in which effervescence is produced by pouring vinegar on soda.

The reciprocity of animal and plant life with respect to carbon dioxide is interesting. Animals inhale oxygen from the atmosphere, and, having converted it into carbon dioxide, respire it. Plants inhale the carbon dioxide, and, having extracted the carbon for their own nutrition, give back oxygen to the air.

WYTHEVILLE, VA.

W. S. SAYERS.

Τ'

TENNYSON'S TWO SEA POEMS

ENNYSON loved all nature, but especially he loved the sea. From boyhood he had found delight in the study of its every mood and change, and over and over again its echoes sound through his verse. In two poems, however, his interpretation of the sea rises into a flood tide of poetic feeling and beauty.

The first of these is the fragment "Break, break, break!" When he wrote it the poet was still a young man, with his fame waiting in the unfolding years; with the ear of the world as yet but grudgingly accorded him; with his heart wrenched by

one of its first great sorrows in the death of Arthur Hallam, whose bride his sister was so soon to have been, and the closeknit friend of his deepest heart,—

"More than my brothers are to me,"

- for whom his love was to flower in that noblest of elegies, "In Memoriam."

It was while this sorrow in its freshness touched and shadowed all the world for Tennyson, that one spring day, as he walked the pleasant English lanes about his early home at Somersby, instead of the green grass under his foot, and the

blossom-starred hawthorn hedges at his hand, he saw a wide gray sea and a gray old church, and, above the song of thrush and skylark, to his inward ear there sounded the rush of incoming waves as they broke white and foaming against the low cliffs not a hundred yards from Clevedon church, under whose aisle Arthur Hallam had found his last resting-place. So, in that solitary walk, out of his saddened heart sprang the now familiar lines:

"Break, break, break,

On thy cold gray stones, O Sea!

And I would that my tongue could utter The thoughts that arise in me.

"And the stately ships go on

To their haven under the hill:

But oh! for the touch of a vanished hand, And the sound of a voice that is still!

"Break, break, break,

At the foot of thy crags, O Sea!

But the tender grace of a day that is dead
Will never come back to me."

A poem that voices, as hardly any other, the hopeless yearning, the longing of bereavement, the sob of all hearts that ache and eyes that weep. It is not as an expression of the sea, but because he has made the sea to stand for the sorrow, the mystery, the inexorableness of death, that the world has made it part of the literature of grief, and multitudes of hearts who never heard the murmur of a wave or watched the foam of a breaker have through it voiced a passion all their own.

Tennyson was an old man of past fourscore when he wrote the other poem which is to this the complement, the antithesis, the gloria for the threnody, "Crossing the Bar." In this the sea is no longer to the poet a lament for the dead, but has become the pathway to immortal life,— "When that which drew from out the boundless deep Turns again home."

Beyond the breakers he sees, not ships of human freightage, but the vision of the Pilot,-"that Divine and Unseen," to quote his words of explanation, "who is always guiding us."

In the long years that lay between the two poems Tennyson had known the best that life can give of love, and honor, and world-wide fame; the obscure young poet who so sadly paced the Somersby lanes had become England's laureate, the friend of England's queen, and one of England's peers. Rich also with heart experience, with high purpose, with fulfilled endeavor, had been these years that had now

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"For though from out our bourne of Time and Place The flood may bear me far;

I hope to see my Pilot face to face
When I have crossed the bar."

That same autumn evening he wrote out the poem and showed it to his son, who at once said, "That is the crown of your life work." It was a well-rendered verdict, and a fruitage worthy to crown Tennyson's ripened years: as simple as the language of a child; as noble as his own great genius; as devout as the faith which had been the cornerstone of his character. That he himself felt it to be the fitting finale of all he had written is shown by the fact that but a few days before his death he charged his son, "Mind you put 'Crossing the Bar' at the end of all editions of my poems."

A little later, and to the music of the great organ of Westminster Abbey a white-robed choir sang. the beautiful words as they laid the poet in his honored grave: and again and again it has been heard beside still forms, where life has passed with that outgoing tide.

As "Break, break, break" has become part of the literature of sorrow, so "Crossing the Bar" has entered into the literature of faith, and many a heart looking to that hour when it in turn shall drift beyond the "bourne of Time and Place" shall voice its own inspiring assurance,—

"I hope to see my Pilot face to face
When I have crossed the bar."

CLEVELAND, O.

ADÈLE E. THOMPSON.

Τ

HAT photography is in these days. making great strides is manifest not only by the many exhibits to be seen in our chief towns and by the founding of Salons where choice specimens of the photographic art are placed permanently on view, but by the appeal of the profession for artistic judgments on the results of its individual and collective work. The desire for criticism is in itself an evidence of progress, while the increasing attractions of the exhibits entitle the profession to the recognition in art circles which photography is now receiving, to the extent even of being accorded space on the walls of the Royal Academy of England and other notable galleries. Those who deem photography merely an interesting pastime and refuse to treat as artistic what they consider only a mechanical "snap-shot" device, will doubtless frown upon the attempt to coquet with camera work and will reject the claim made for it to rank among the fine arts. This attitude, however, is inconsiderate and even unfair, when we note not only how much pictorial and decorative value there is in a modern photograph, but recognize its many delicate beauties, and, in the hands of a clever practitioner, the high distinction reached in skilled photography, with its delightful surprises and numberless subtle pictorial effects. Nor, aside from our interest in its charmingly varied products, would it be just to shut our eyes to the fact that photography has exerted an important influence upon art, which

has thus been cheapened to its students and lovers, or to the further fact that, as has been claimed for it, the work of the camera has largely influenced the artist in the choice of a subject. It is a cheap-a superciliousway of treating it to think of it only as a mechanical device - a matter of putting in a glass plate or a film in a black box, focusing, and then pressing the button. There is, of course, this mechanical labor in photography, as there is in much else

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of machine-made work; but the product, nevertheless, is often art, since brains and art taste and feeling have to do with it; and, where there is an artist at work, there are the qualities that go to make an artistic production.

Much, obviously and necessarily, depends upon the operator. What differ

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AN IDEALIZED PORTRAIT FROM LIFE

ences there are, both among amateurs and professionals, may be seen at a glance at the displays in some photographic exhibition, even where only excellent work is exhibited. What contrasts there are, even in the better class of work, it does not take a professional to note. In one exhibit we sometimes detect a certain quality which we find missing in its neighbor, while in portrait work one artist will give a character and individuality to his (425)

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siasts, but have attracted also trained and well-equipped artists, numbers of whom have sought out and highly commended his work. In the Salon several notable examples of his art have been given a place on the walls. These include both landscape and portrait work, and each possesses the strong and distinctive qualities characteristic of high art. Some examples of Mr. Minns's work will be found in these pages, though in the half-tone reproductions not a little is necessarily lost, both of the portrait strength and, in the case of landscapes, of their subtle atmospheric beauty. The out-of-door subjects consist of scenes in and near the valley of the Cuyahoga River, in the vicinity of Akron. The feeling and sentiment in these examples are as apparent as are the skill and judgment which have enabled Mr. Minns to seize the conditions of light and atmosphere most favorable to the making of an artistic picture. Strong and realistic is Mr. Minns's work in portraiture: this is specially seen in the head designed

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H. W. MINNS (Photographed by Eva Gamble Walborn) subject which another utterly fails to impart. Nor are these differences those alone inherent in the picture-subjects exhibited, be they portrait or landscape. They are due chiefly to the educated taste and feeling of the manipulator and to the intelligent study of his profession and the high ideal he has of his art. A notable example of this we have recently had the pleasure of meeting with in the person and work of a clever Ohio photographer, many of whose excellent pictures have received commendation in high art circles and been received with distinction in the photographic Salon lately founded in the State, as well as at the national conventions of the profession held at Celeron, on Lake Chautauqua, and at Put-in-Bay, on Lake Erie.

The photographer to whom we refer is Mr. Harvey W. Minns, of Akron, Ohio; a true artist, who possesses not only great enthusiasm for his work, but has the nous, the intelligent perception of his art, which enables him constantly to elevate his ideals and artistically to increase the high character of his productions. Mr. Minns's exhibits have caught the eye not only of many amateur and professional enthu

A PORTRAIT

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