Otago Hands and Hearts.

Otago Witness, Issue 1650, 7 July 1883, Page 1 (Supplement)

Otago Hands and Hearts.

FNo. III.— A Visit to the Gasworks.

" Light, light, more light !"— the dying worda of an eminent man — may be taken as expressive not only of the sore need of man's spiritual nature, but also as representing the constant cry of the race even till the present day as concerns its temporal and physical needs. The good King Alfred rests one of his claims to the gratitude of posterity on the fact of his invention of a graduated, and therefore, presumablyv regularly-burning candle, which should mark the flight of time ; and among the inventors of to-day are there any that attract a greater share of the public notice than they whoaa every effort is directed to the production of an entirely satisfactory electric light? Coal gas— though the days of its sovereignty as an illuminating medium may be prognosticated to be reaching their end— is not yet deposed from its high position, and seeing how much the minda of one portion of the community at least have lately seemed to be exercised in connection with the cost of its production, and with other matters relevant thereto, it may not be out of place to give to the layman in affairs gaseoussome general idea of the process of manufacture as carried on in this vicinity. Ana for this purpose we will pay a visit to the Gasworks at Kensington or at Caversham at whatever hour of the 24 that maybest suit us; for, be it remembered, tha furnaces here, like the sacred fire, the vestals care, are never permitted to go out. And if our first approach be made in the " stilly hour of night," how strange the scene! But a. moment ago we were in the silent street, where no sign even of life itself was visible, and now we stand in the presence of flesh and blood commentaries on the primeval curse, In thfr sweat of thy face shalt thou eat bread. If. ever there was a spot calculated to arouse in the imaginative mind the fancies of the supernatural, then surely in this place at dead oi night may be found excuse for any lingering belief in ghouls and suchlike spirits of the dark. In front of him who at such an hour enters these mysterious shades are row on row of grim, and blackened pipes, as of some organ of Hades, whose music is set forth in periods by dull ana sullen " booms " that speak of rage repressed, and by the occasional " clink " of some falling tool. And while the ear attends these Acherontic sounds, and the eye is attracted tothe lambent flames that play around the crevices of these tubes, a new glamour is added to the scene by the appearance of several grimy giants, as, in the flickering light, they seem. These are, however, but the stokers, whose duty it is at regular intervals (of about three hours) to " draw the charges" and refill ther retorts, for it is to the " retort-house " that we repair to watch the initiatory processes in thia manufacture. From bolow each one of these upright pipes there extends rearwards a, cylinder constructed of fireclay 'to receive thecoal that furnishes our gas. Now these cylinders or retorts may either be single (or halfthroughs ") or they may be " through-retorts," 1 which means that they may have a door on mouthpiece at each end of a tube some ISffc long, or may be but one-half that length, in which case a substantial brick wall will close, up the farther end. It is practically admitted at the present day by all engineers of repute that the through-retort furnishes the best result where a large quantity of gas is being made*, but economic reasons with reference to tha amount of labour employed have often led to tha adoption of the other and older system. In the Dunedin Gasworks both kinds may be seen in use ; but it is unfortunate that the pipes constructed on the better principle are in several instances in a sadly dilapidated condition, and it may be feared whether even their repair by skilled and careful workmen will enable them, much longer to render effective service. To, return to our process : One man whose hands are usually encased in leathern gloves loosens

the bolt that screws the furnace door, and swiftly applies to the thus-made orince a, live cinder, which kindles the escaping remnant of gas, and passes on to the next in the row. After a brief interval the -closing plate is altogether removed, and forth Tushes the angry yet impotent flame, impotent because, to use a metaphor of Irish construction "the wind has been taken out of its sails" by the prompt ignition of the gas whereon it might otherwise have fed. Into the opened tube is thrust an iron instrument that looks like a toothpick 10,000 times magnified, the crook at the end of which grips with resistless hold what once was coal but now is coke, and at the bidding of a stalwart pair of arms drags it swiftly ts the mouth, from which it "tumbles more than red hot upon the floor or into Ibarrows placed beneath the mouths of the xetorts. Upon these fiery masses buckets of "water are dashed, and out into the adjacent -yard they are wheeled and overturned in heaps. But the water notwithstanding, " still in their ashes live their wonted fires," and around the base of the great heap of coke there burn and smoke at intervals miniature volcanoes. Immediately after the clearing of the letorts the new charges are put in by means of iron scoop 3, that strongly resemble enormous ■cheese-tasters, or in the case of the smaller Tetorts, as at Oavereham, by the use of the shovel only. One man takes hold of the cross handle of this scoop, and other two insert beneath it a rod curved in the middle, which supports the weight ; then with quick «tcp they advance to the open door and thrust their burden in ; a quick turn of the wrists, and the scoop is reversed, and as speedily •withdrawn, leaving the fuel behind. So dexterously is this feat performed that it looks almost easy ; but one must not judge by appearances in this case, for the streaming brows «f the workmen show, as does their scanty attire, how toilsome is their labour. In some of the works in England a mechanical contrivance known as "the iron man" bas been introduced to save much of this expenditure of strength, but whether proved to be a complete success o** no, it has anot yet been introduced here. Once within these glowing receptacles, the coal is fast deprived of its gas and tar, and the former product passes up the tubes at the front of the furnaces into what is called "the hydraulic main," which serves to shut off the gas from all chance of escape, and also to receive and retain some of the impurities with which it is admixed. Hence the gas, .still in a very crude condition, is conveyed to the condenser, the object of which machine is to reduce to a liquid form the tarry and ammoniacal vapours which -eriously affect the illuminating power, md to preserve, moreover, substances which, as thus reduced, are not without a marketable value. The condenser, as originally constructed, consisted of a number of "vertical tubes of considerable height, connected by smaller ones running in a slanting direction ; but in addition to this may also be seen another machine, in which the main pipes run horizontally, and this bears the name of the present engineer of the Dunedin Gasworks. ■Our gas passes next into the "washer," whose water performs the first of the cleansing operations proper, and from this to the " scrubber," "which in its old-fashioned form was a towering cylinder, filled with layers of ammonia, wood in short lengths, and brushwood, but which, by means of comparatively recent improvements, has bee^ reduced to much less cumbersome proportions. After passing through this, it is then carried into the " purifiers," usually four in number, containing lime, oxide of iron, or some similar agent, which tends to remove the particles of sulphur, icarbonic acid, &c. From this the gas finally emerges fit for consumption, and, through the " governor," passes into the gigantic " holder" that distributes it along the various mains into our streets and highways. The meter-room, with several clever contrivances, now claims our attention, and here we take the opportunity of testing, by means of an elegant little machine, the illuminating power of our newly-manufactured gas, which we find to give the very fairly satisfactory result of 18 J candle-power. The neatly-kept engine and beilers are also not without their interest to the visitor, and the various operations carried on in the yards, such as the screening of coke for making asphalt, and the packing of coke in bags for private use. There seems to be a tremendous waste of space in the Dunedin works, and surely the retort-houses might, with regard to economy of labour, have been placed in closer iuxtaposition. Before tho • price of gas is likely to be very materially reduced it •would F"em that some few alterations must necessarily be effected, as it cannot be said that the works are convenient in structure. The floors, for instance, are terribly irregular, and surely at a level that brings them too much under the influence of the damp vapours which arise from the morass below. The directors, however, appear to be awake to this fact, and a few new retorts are now being "set" by a skilful workman, who was but a year or two since engaged on a job at the works in Ramsgate, Engai; 6 .which have since proved themselves one of the most profitable concerns of the sort. ~"TheBO new retorts are to be of what is loiown as the "D" shape. By the use of these, with some other little improvements, it is hoped that something will be effected towards the reduction of the quantity of naphthaline now deposited in the retorts. A most unpro--fitable compound this, chemically known as >Cio Hg, for the illuminating power of gas depends chiefly on the proportion of carbon it -contains, and this is therefore so much loss. The works at Oaversham are too young to allow of very special mention, though it may be stated that in some particulars they have very special merit. It is to be hoped that the man who here undertakes the special toils and risks of a solitary charge of the works from 6 p.m. to 6 a.m. is adequately remunerated for his uuonviable task. And now let us home and to bed, but not " by the struggling moonbeams' misty light"; we will turn up the "gas."