February 12th 1875.

  THE CHARITY BAZAAR: AN ALLEGORICAL DIALOGUE

  PERSONS OF THE DIALOGUE

  The Ingenuous Public

  His Wife

  The Tout

  The Tout, in an allegorical costume, holding a silver trumpet in his right hand, is discovered on the steps in front of the Bazaar. He sounds a preliminary flourish.

  The Tout. — Ladies and Gentlemen, I have the honour to announce a sale of many interesting, beautiful, rare, quaint, comical, and necessary articles. Here you will find objects of taste, such as Babies’ Shoes, Children’s Petticoats, and Shetland Wool Cravats; objects of general usefulness, such as Tea-cosies, Bangles, Brahmin Beads, and Madras Baskets; and objects of imperious necessity, such as Pen-wipers, Indian Figures carefully repaired with glue, and Sealed Envelopes, containing a surprise. And all this is not to be sold by your common Shopkeepers, intent on small and legitimate profits, but by Ladies and Gentlemen, who would as soon think of picking your pocket of a cotton handkerchief as of selling a single one of these many interesting, beautiful, rare, quaint, comical, and necessary articles at less than twice its market value. (He sounds another flourish.)

  The Wife. — This seems a very fair-spoken young man.

  The Ingenuous Public (addressing the Tout). — Sir, I am a man of simple and untutored mind; but I apprehend that this sale, of which you give us so glowing a description, is neither more nor less than a Charity Bazaar?

  The Tout. — Sir, your penetration has not deceived you.

  The Ingenuous Public. — Into which you seek to entice unwary passengers?

  The Tout. — Such is my office.

  The Ingenuous Public. — But is not a Charity Bazaar, Sir, a place where, for ulterior purposes, amateur goods are sold at a price above their market value?

  The Tout. — I perceive you are no novice. Let us sit down, all three, upon the doorsteps, and reason this matter at length. The position is a little conspicuous, but airy and convenient.

  (The Tout seats himself on the second step, the Ingenuous Public and his Wife to right and left of him, one step below.)

  The Tout. — Shopping is one of the dearest pleasures of the human heart.

  The Wife. — Indeed, Sir, and that it is.

  The Tout. — The choice of articles, apart from their usefulness, is an appetising occupation, and to exchange bald, uniform shillings for a fine big, figurative knick-knack, such as a windmill, a gross of green spectacles, or a cocked hat, gives us a direct and emphatic sense of gain. We have had many shillings before, as good as these; but this is the first time we have possessed a windmill. Upon these principles of human nature, Sir, is based the theory of the Charity Bazaar. People were doubtless charitably disposed. The problem was to make the exercise of charity entertaining in itself — you follow me, Madam? — and in the Charity Bazaar a satisfactory solution was attained. The act of giving away money for charitable purposes is, 215 by this admirable invention, transformed into an amusement, and puts on the externals of profitable commerce. You play at shopping a while; and in order to keep up the illusion, sham goods do actually change hands. Thus, under the similitude of a game, I have seen children confronted with the horrors of arithmetic, and even taught to gargle.

  The Ingenuous Public. — You expound this subject very magisterially, Sir. But tell me, would it not be possible to carry this element of play still further? and after I had remained a proper time in the Bazaar, and negotiated a sufficient number of sham bargains, would it not be possible to return me my money in the hall?

  The Tout. — I question whether that would not impair the humour of the situation. And besides, my dear Sir, the pith of the whole device is to take that money from you.

  The Ingenuous Public. — True. But at least the Bazaar might take back the tea-cosies and pen-wipers.

  The Tout. — I have no doubt, if you were to ask it handsomely, that you would be so far accommodated. Still it is out of the theory. The sham goods, for which, believe me, I readily understand your disaffection — the sham goods are well adapted for their purpose. Your lady wife will lay these tea-cosies and pen-wipers aside in a safe place, until she is asked to contribute to another Charity Bazaar. There the tea-cosies and pen-wipers will be once more charitably sold. The new purchasers, in their turn, will accurately imitate the dispositions of your lady wife. In short, Sir, the whole affair is a cycle of operations. The tea-cosies and pen-wipers are merely counters; they come off and on again like a stage army; and year after year people pretend to buy and pretend to sell them, with a vivacity that seems to indicate a talent for the stage. But in the course of these illusory manœuvres, a great deal of money is given in charity, and that in a picturesque, bustling, and agreeable manner. If you have to travel 216 somewhere on business, you would choose the prettiest route, and desire pleasant companions by the way. And why not show the same spirit in giving alms?

  The Ingenuous Public. — Sir, I am profoundly indebted to you for all you have said. I am, Sir, your absolute convert.

  The Wife. — Let us lose no time, but enter the Charity Bazaar.

  The Ingenuous Public. — Yes; let us enter the Charity Bazaar.

  Both (singing). — Let us enter, let us enter, let us enter, Let us enter the Charity Bazaar!

  (An interval is supposed to elapse. The Ingenuous Public and his Wife are discovered issuing from the Charity Bazaar.)

  The Wife. — How fortunate you should have brought your cheque-book!

  The Ingenuous Public. — Well, fortunate in a sense. (Addressing the Tout.) — Sir, I shall send a van in the course of the afternoon for the little articles I have purchased. I shall not say good-bye; because I shall probably take a lift in the front seat, not from any solicitude, believe me, about the little articles, but as the last opportunity I may have for some time of enjoying the costly entertainment of a drive.

  The Scene Closes

  * * *

  THE LIGHT-KEEPER

  I

  The brilliant kernel of the night,

  The flaming lightroom circles me:

  I sit within a blaze of light

  Held high above the dusky sea.

  Far off the surf doth break and roar

  Along bleak miles of moonlit shore,

  Where through the tides the tumbling wave

  Falls in an avalanche of foam

  And drives its churnèd waters home

  Up many an undercliff and cave.

  The clear bell chimes: the clockworks strain:

  The turning lenses flash and pass,

  Frame turning within glittering frame

  With frosty gleam of moving glass:

  Unseen by me, each dusky hour

  The sea-waves welter up the tower

  Or in the ebb subside again;

  And ever and anon all night,

  Drawn from afar by charm of light,

  A sea-bird beats against the pane.

  And lastly when dawn ends the night

  And belts the semi-orb of sea,

  The tall, pale pharos in the light

  Looks white and spectral as may be.The early ebb is out: the green

  Straight belt of sea-weed now is seen,

  That round the basement of the tower

  Marks out the interspace of tide;

  And watching men are heavy-eyed,

  And sleepless lips are dry and sour.

  The night is over like a dream:

  The sea-birds cry and dip themselves;

  And in the early sunlight, steam

  The newly-bared and dripping shelves,

  Around whose verge the glassy wave

  With lisping wash is heard to lave;

  While, on the white tower lifted high,

  With yellow light in faded glass

  The circling lenses flash and pass,

  And sickly shine against the sky.

  1869.

  II

  As the steady lenses circle

  With a frosty gleam of glass;

  And the clear bell chimes,

  And the oil brims over the lip of the burner,

  Quiet and still at his desk,

  The lonely light-keeper

  Holds his vigil.

  Lured from afar,

  The bewildered sea-gull beats

  Dully against the lantern;

  Yet he stirs not, lifts not his head

  From the desk where he reads,

  Lifts not his eyes to see

  The chill blind circle of night

  Watching him through the panes.This is his country’s guardian,

  The outmost sentry of peace.

  This is the man,

  Who gives up all that is lovely in living

  For the means to live.

  Poetry cunningly gilds

  The life of the Light-Keeper,

  Held on high in the blackness

  In the burning kernel of night.

  The seaman sees and blesses him;

  The Poet, deep in a sonnet,

  Numbers his inky fingers

  Fitly to praise him:

  Only we behold him,

  Sitting, patient and stolid,

  Martyr to a salary.

  1870.

  ON A NEW FORM OF INTERMITTENT LIGHT FOR LIGHTHOUSES

  The necessity for marked characteristics in coast illumination increases with the number of lights. The late Mr. Robert Stevenson, my grandfather, contributed two distinctions, which he called respectively the intermittent and the flashing light. It is only to the former of these that I have to refer in the present paper. The intermittent light was first introduced at Tarbetness in 1830, and is already in use at eight stations on the coasts of the United Kingdom. As constructed originally, it was an arrangement by which a fixed light was alternately eclipsed and revealed. These recurrent occultations and revelations produce an effect totally different from that of the revolving light, which comes gradually into its full strength, and as gradually fades away. The changes in the intermittent, on the other hand, are immediate; a certain duration of darkness is followed at once and without the least gradation by a certain period of light. The arrangement employed by my grandfather to effect this object consisted of two opaque cylindric shades or extinguishers, one of which descended from the roof, while the other ascended from below to meet it, at a fixed interval. The light was thus entirely intercepted.

  At a later period, at the harbour light of Troon, Mr. Wilson, C.E., produced an intermittent light by the use of gas, which leaves little to be desired, and which is still in 221 use at Troon harbour. By a simple mechanical contrivance, the gas jet was suddenly lowered to the point of extinction, and, after a set period, as suddenly raised again. The chief superiority of this form of intermittent light is economy in the consumption of the gas. In the original design, of course, the oil continues uselessly to illuminate the interior of the screens during the period of occultation.

  Mr. Wilson’s arrangement has been lately resuscitated by Mr. Wigham of Dublin, in connection with his new gas-burner.

  Gas, however, is inapplicable to many situations; and it has occurred to me that the desired result might be effected with strict economy with oil lights, in the following manner: —

  Fig. 1.

  In Fig. 1, AAA represents in plan an ordinary Fresnel’s dioptric fixed light apparatus, and BB’ a hemispherical mirror (either metallic or dioptric on my father’s principle) which is made to revolve with uniform speed about the burner. This mirror, it is obvious, intercepts the rays of one hemisphere, and, returning them through the flame (less loss by absorption, etc.), spreads them equally over the other. In this way 180° of light pass regularly the eye of the seaman; and are followed at once by 180° of darkness. As the hemispherical mirror begins to open, the observer receives the full light, since the whole lit 222 hemisphere is illuminated with strict equality; and as it closes again, he passes into darkness.

  Other characteristics can be produced by different modifications of the above. In Fig. 2 the original hemispherical mirror is shown broken up into three different sectors, BB´, CC´, and DD´; so that with the same velocity of revolution the periods of light and darkness will be produced in quicker succession. In this figure (Fig. 2) the three sectors have been shown as subtending equal angles, but if one of them were increased in size and the other two diminished (as in Fig. 3), we should have one long steady illumination and two short flashes at each revolution. Again, the number of sectors may be increased; and by varying both their number and their relative size, a number of additional characteristics are attainable.

  Fig. 2.

  Colour may also be introduced as a means of distinction. Coloured glass may be set in the alternate spaces; but it is necessary to remark that these coloured sectors will be inferior in power to those which remain white. This objection is, however, obviated to a large extent (especially where the dioptric spherical mirror is used) by such an arrangement as is shown in Fig. 4; where the two sectors, WW, are left unassisted, while the two with the red 223 screens are reinforced respectively by the two sectors of mirror, MM.

  Fig. 3.

  Fig. 4.

  Another mode of holophotally producing the intermittent light has been suggested by my father, and is shown in Fig. 5. It consists of alternate and opposite sectors of dioptric spherical mirror, MM, and of Fresnel’s fixed light apparatus, AA. By the revolution of this composite frame about the burner, the same immediate alternation of light and darkness is produced, the first when the front of the 224 fixed panel, and the second when the back of the mirror, is presented to the eye of the sailor.

  Fig. 5.

  One advantage of the method that I propose is this, that while we are able to produce a plain intermittent light; an intermittent light of variable period, ranging from a brief flash to a steady illumination of half the revolution; and finally, a light combining the immediate occultation of the intermittent with combination and change of colour, we can yet preserve comparative lightness in the revolving parts, and consequent economy in the driving machinery. It must, however, be noticed, that none of these last methods are applicable to cases where more than one radiant is employed: for these cases, either my grandfather’s or Mr. Wilson’s contrivance must be resorted to.

  1871.

  Read before the Royal Scottish Society of Arts on 27th March 1871, and awarded the Society’s Silver Medal.

  ON THE THERMAL INFLUENCE OF FORESTS

  The opportunity of an experiment on a comparatively large scale, and under conditions of comparative isolation, can occur but rarely in such a science as Meteorology. Hence Mr. Milne Home’s proposal for the plantation of Malta seemed to offer an exceptional opportunity for progress. Many of the conditions are favourable to the simplicity of the result; and it seemed natural that, if a searching and systematic series of observations were to be immediately set afoot, and continued during the course of the plantation and the growth of the wood, some light would be thrown on the still doubtful question of the climatic influence of forests.

  Mr. Milne Home expects, as I gather, a threefold result: — 1st, an increased and better regulated supply of available water; 2nd, an increased rainfall; and, 3rd, a more equable climate, with more temperate summer heat and winter cold. As to the first of these expectations, I suppose there can be no doubt that it is justified by facts; but it may not be unnecessary to guard against any confusion of the first with the second. Not only does the presence of growing timber increase and regulate the supply of running and spring water independently of any change in the amount of rainfall, but as Boussingault found at Marmato, denudation of forest is sufficient to decrease that supply, even when the rainfall has increased instead 226 of diminished in amount. The second and third effects stand apart, therefore, from any question as to the utility of Mr. Milne Home’s important proposal; they are both, perhaps, worthy of discussion at the present time, but I wish to confine myself in the present paper to the examination of the third alone.

  A wood, then, may be regarded either as a superficies or as a solid; that is, either as a part of the earth’s surface slightly elevated above the rest, or as a diffused and heterogeneous body displacing a certain portion of free and mobile atmosphere. It is primarily in the first character that it attracts our attention, as a radiating and absorbing surface, exposed to the sun and the currents of the air; such that, if we imagine a plateau of meadow-land or bare earth raised to the mean level of the forest’s exposed leaf-surface, we shall have an agent entirely similar in kind, although perhaps widely differing in the amount of action. Now, by comparing a tract of wood with such a plateau as we have just supposed, we shall arrive at a clear idea of the specialities of the former. In the first place, then, the mass of foliage may be expected to increase the radiating power of each tree. The upper leaves radiate freely towards the stars and the cold inter-stellar spaces, while the lower ones radiate to those above and receive less heat in return; consequently, during the absence of the sun, each tree cools gradually downward from top to bottom. Hence we must take into account not merely the area of leaf-surface actually exposed to the sky, but, to a greater or less extent, the surface of every leaf in the whole tree or the whole wood. This is evidently a point in which the action of the forest may be expected to differ from that of the meadow or naked earth; for though, of course, inferior strata tend to a certain extent to follow somewhat the same course as the mass of inferior leaves, they do so to a less degree — conduction, and the conduction of a very slow conductor, being substituted for radiation.

  We come next, however, to a second point of difference. 227 In the case of the meadow, the chilled air continues to lie upon the surface, the grass, as Humboldt says, remaining all night submerged in the stratum of lowest temperature; while in the case of trees, the coldest air is continually passing down to the space underneath the boughs, or what we may perhaps term the crypt of the forest. Here it is that the consideration of any piece of woodland conceived as a solid comes naturally in; for this solid contains a portion of the atmosphere, partially cut off from the rest, more or less excluded from the influence of wind, and lying upon a soil that is screened all day from isolation by the impending mass of foliage. In this way (and chiefly, I think, from the exclusion of winds), we have underneath the radiating leaf-surface a stratum of comparatively stagnant air, protected from many sudden variations of temperature, and tending only slowly to bring itself into equilibrium with the more general changes that take place in the free atmosphere.