Science as an aid to world culture and civilization

Denham, H. G. (Henry George), Cawthron Institute, Nelson, N. Z., 1938

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Title: Science as an aid to world culture and civilization

Author: Denham, H. G. (Henry George)

Published: Cawthron Institute, Nelson, N. Z., 1938

The Cawthron Institute

NELSON, NEW ZEALAND.

Cawthron Lecture 1937.

Science as an Aid to World Culture and Civilization

H. G. DENHAM, MA., Ph.D., F.1.C., F.R.S.N.Z.

R. W. STILES 4 CO. LTD.. PRINTERS, NELSON

1938

SCIENCE AS AN AID TO WORLD CULTURE AND CIVILIZATION.

BY H. G. Denham, M.A., D.Sc, Ph.D., F.1.C., F.R.S.N.Z.

The magnificent record of the Cawthron Institute makes one deeply conscious of the responsibility incurred when one is called upon to give the Annual Cawthron Lecture, commemorating the far-sighted generosity and public spirit of your founder, Thomas Cawthron. The high repute in the chemical world of both your late and your present Director gives an added responsibility to a lecturer whose own profession is that of Chemist. This evening I propose to traverse some of the outstanding contributions of science, especially by the very nature of things chemical science, towards world culture and civilization.

By long and painful travail, often by sending to the stake or the dungeon those who were over anxious to seek and to proclaim the truth, the human race has come to cherish all that speaks of scholarship and learning. The day of the stake and the dungeon has gone and in their stead broadminded men have created colleges, universities and institutes which serve as the focal point from which all knowledge emanates. Science which after all is merely organised knowledge, owes much to the inspiration which to be found in the many Research Institutes and Universities scattered throughout every country. Probably at no period in the earth's history has there been so rich a harvest of scientific achievements as during the past thirty years, so much so that the amazing labour-saving devices which the scientist and the engineer have perfected, have often had the finger of accusation pointed at them as being responsible in large measure for the grave world chaos. Not long ago a leading scientific journal remarked: "Nature is very wasteful and we are always interfering with the methods of nature; we spend immense sums in finding out how to prevent beetles from devouring timber, or preventing other insects from spoiling grain, potatoes and leather, and in increasing the yield of other products. We preserve tons of perfectly good fruit and vegetables which twenty years ago would have perished from lack of attention. Nature is prodigal of life; the weakly and the diseased die off speedily; we try to preserve to the

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uttermost limit the most useless and the least promising of lives. One result of all this departure from the conditions of nature is that we do not quite know what to do By preventing all the waste we have now a superfluity of almost everything and often we cannot use it Stainless steel that will not corrode, chromium-plated parts of motor-cars, wood that resists the furniture beetle leather that won't wear out, all such things are the curse of modern times. We shall soon have no end of books and magazines that no one will wish to keep at home unless some great genius, some far-seeing Pasteur or Faraday, sees fit to invent a new synthetic paper guaranteed to remain intact for twenty years and then suddenly to disintegrate."

Whilst many of us are prepared to concede that grave industrial unrest has often followed as the result of scientific discoveries, the difficulty has arisen not from the incapacity of the scientist to do his share, but rather from the inability of man to understand man. Modern developments have led to the turning loose of unlimited resources without regard to their social implications. A hundred years ago the power looms of England destroyed the cotton weaving industry, and during the early years of that impact misery strode over the countryside of England and there resulted an accumulation of wealth in the hands of the nouveaux riches who used their capital to exploit their gains over the entire world. That kind of thing has been done again and again in the past, and we have called it progress, because the power of man over nature was ever on the increase, and because in the long run the common man shared in the distribution in the way of reduced working hours and an improved scale of living. What happened to the common man in the short run was all too frequently nobody's concern—laissez faire at its worst. All too often we have overlooked the fact that creative science, capital and skilled labour, form three legs of the tripod upon which modern industrial development rests. There can be no real stability, no real progress, unless each foot rests firmly upon the ground of their common interest, unless each bears its share of the structure erected at their common desire. Without this triple alliance based on the mutual interest and the loyal cooperation of the investigator, the alert manufacturer and the willing, artisan, no scientific discovery will make a real contribution to the well-being of the world at large, nor can the people long remain in that happy contented frame of mind that speaks of real prosperity and of the realisation of sound ideals of civilization. Invention and discovery have unquestionably contributed their quota

FIG. IV. GENERAL ARRANGEMENT OF HYDROGENATION STALL.

FIG. I. BERGIUS' HYDROGENATION PLANT (PRE-WAR).

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towards an increased production both of goods and of services, and have done much to free mankind from his age-long slavery to the earth. If we have made it possible to grow more food with less land and labour, millions will have more leisure for other things. If we have found ways of producing clothing in richer abundance, has not this meant additional comfort to mankind? The high per capita production of goods which the scientist and the engineer have made possible has meant more goods, more comfort, more leisure than ever before.

SYNTHETIC OIL FUELS.

I propose at this stage to single out a few important products in the production or utilisation of which there have been notable advances during recent years. Probably no discovery has so completely revolutionised the world in so short a time as the internal combustion engine, and the provision of an adequate supply of fuel for our cars and planes is probably a sufficient justification for turning our attention to the fuel problem. Varying estimates have been given as to the life of the oil wells at present in sight, and these estimates rarely exceed twenty years, for one must remember that the rate of increase of fuel oil consumption has in recent years been stupendous, and is likely to be even greater. Additional supplies, whether natural or synthetic, are therefore of paramount importance to the civilization of to-day. Refined petrol consists of about 85 p.c. carbon and fifteen p.c. hydrogen. Coal is largely built of the same two constituents, but in the proportion of 95 to 5. The development of the modern hydrogenation process for obtaining petrol from coal involves so acting upon the coal with hydrogen as to increase this hydrogen ratio to that pertaining, in petrol.

Fig 1.

The initial steps in developing the technique of this process were made by Bergius in pre-War days, culminating in a small technical plant which operated at Rheinau till 1927. The Bergius patents were acquired by the I. G. Farben-industrie, and the first commercial plant was built at Leuna in 1927, capable of producing annually 100,000 tons of petrol from brown coal. The Standard Oil Company, quick to realise the possible application of the process for increasing the yield of petrol from crude petroleum linked up with the I.G. at this stage. Shortly after this the big British Chemical combine, the 1.C.1., turned their attention to the possible conversion of bituminous coal to petrol. With their unrivalled

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knowledge of the technique of high pressure-temperature reactions progress with their pilot plant was rapid, and within three years they announced a 60 p.c conversion of coal to petrol—roughly 140 gallons per ton of coal. The four major companies interested (including the bhell group) amalgamated in 1931, and since then the pooling of all technical resources has led to rapid improvements. The British Government has encouraged the 1.0.1. in their hydrogenation project by allowing them a total rebate of 36d. spread over a limited number of years, actually a tax-rebate of Bd. per gallon for 4A years has been agreed upon. The growth of these petrol plants can be gauged by the fact that in the Ruhr the Hiberma plant is being built to produce annually 125,000 tons of petrol from bituminous coal, while the Leuna plant has been extended to produce 325,000 tons per annum from brown coal. Two further plants, each capable of an annual output of 150,000 tons of petrol are also in course of erection. The British plant at Billmgham has an output of 150,000 tons, of which 10,000 tons comes from low temperature tar, 40,000 tons from creosote oil and the balance from bituminous coal.

The successful conversion of coal to petrol depends upon the accurate knowledge of the most suitable temperature, pressure and duration of the reaction, as well as of the catalyst necessary for the speeding up of the process. Actually the most suitable pressure is 200 atmospheres, whilst the temperature maintained m the converter is about 400° C, though a certain flexibility is necessary here to meet the requirements of the different types of coal. The reaction takes place with considerable heat evolution, so that the design of the plant must provide for the removal of this heat. The I.G. and the 1.C.1, companies have both carried out extensive work to determine the most satisfactory form of catalyst to employ in order to speed up the conversion. In practice compounds of tin are automatically injected into the converters where the coal-oil paste is being, hydrogenated, whilst grids of the catalyst are used where the middle oil, etc., is undergoing hydrogenation. Figure 2 gives a diagrammatical lay-out of the plant.

Fig. 2.

One of the most important discoveries of the research staff has revealed that the presence of considerable amounts of hydrogen chloride also aid the conversion of petrol. It is now the custom to introduce relatively large amounts of this gas as an additional catalyst, a specially designed oil-alkali washer removing this corrosive gas whilst the pressure is still 200 atmos-

FIG 11. DIAGRAMMATIC LAY-OUT OF HYDROGENATION PLANT.

FIG. 111. DIAGRAM OF BILLINGHAM PLANT

FIG. V. CONVERTER BEING LIFTED BY A TITAN CRANE.

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pheres. The acid gas has little corrosive action in the hot converters, but must be removed before it enters the cooler part of the plant. Fig. 3 gives the complete layout of the plant as it now operates at Billingham.

Fig 3.

The ground coal is worked into a thick paste with tar, heavy oil, etc., and after passing through the heat interchangers and preheaters, is fed into the converters with the requisite amount of catalyst. Here the reaction with hydrogen takes place, and from the converters there issue gases, petrol and oil vapours, and unreached sludge. Part of this sludge is returned to the unit, the balance is filtered in order to make the unchanged oil available for the preparation of fresh paste, the cokey powder filtered from the oil going off to the boilers. Of the volatile gases recovered from the converters the liquid fraction undergoes separation into petrol and middle oil, which is returned for further treatment with hydrogen. The gaseous products are burnt as fuel after the valuable butane has been removed as bottled gas for sale as an illuminant.

The burning of the gases under the furnaces is a false economy forced upon the Company by reason of its having developed a very suitable process for making hydrogen from water gas. Enormous quantities of hydrogen are required for the manufacture of ammonia, and the plant for making this hydrogen involves the passage of steam over heated coke. The carbon mon-oxide-hydrogen-steam mixture is then passed at a much lower temperature over a catalyst when an equilibrium mixture of carbon dioxide-hydrogen is formed. The former is readily removed together with traces of monoxide. For the purpose of ammonia production this is a most economic process for making hydrogen, and where additional supplies of this gas were needed for the coal plant an extension of the existing facilities supplied the new demand. Actually, however, a new plant, which has not been committed to the water gas process, has available in the exit gases from the converters the raw product for making hydrogen. These gases contain large amounts of hydro-carbons (methane, etc.) which when mixed with steam and passed over catalysts, yield all the hydrogen a hydrogenation plant requires at a much reduced cost. Figure 4 (Hydrogenation stall), Figure 5 (converter), and Figure 6 (Billingham works) give an idea of the enormous scope of a plant designed to produce 150,000 tons per annum of petrol. Recent improvements in technique have probably increased the yield per ton of coal treated to about 180 gallons, definitely well above the original 60 p.c. yield. From

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tar, of course, close on 90 p.c. conversion by weight can be effected. The Billingham plant finds it necessary to use 4 tons of coal for the production of power, hydrogen, etc., in order to convert 1 ton of coal into its equivalent of petrol. With a new plant using the latest process of producing hydrogen, only 2.5 to 3 tons of coal are required for the purpose. The actual cost ot the Billingham works was £5,500,000. It is estimated that a similar plant erected in New Zealand at the present day would cost approximately eleven to twelve million pounds. The probable cast of production per gallon would be not less than lOd. and possibly as high as 1/-. In the erection of such a plant it must be remembered that the capital cost is so high, and the danger of explosion so great, that it is inconceivable that a location would be chosen which is not removed as far as possible from the risk of earthquakes.

When the oil industry had passed through its initial period of commercial exploitation, the scientist was called in to devise methods of production and refinement of the new oil. To-day the man of science reigns supreme in this industry. Every phase in the utilisation of crude petroleum is now under strict scientific control. Its location is determined by methods of geophysical and geological survey; wells are sunk no longer to a depth of fifty odd feet, but deep down to the reservoirs 11,000 ft. below the earth's surface; whilst to maintain the pressure necessary for forcing out the oil, the natural gas given off is in some cases stripped of its petrol and pumped back into the bowels of the earth. Indeed in some limestone areas, immense quantities of hydrochloric acid are pumped down in order that the evolved carbon dioxide gas may force out the oil. It is estimated that this process has increased the yield of some three thousand wells by 448 p.c. The first oil well is reported to have been accidentally discovered in 1829 when a pioneer in Burksville started drilling near the Cumberland River for salt water, with the determination, as he said, to "strike salt water or to strike hell." Suddenly there was a roar. The drilling tools shot high in the air, followed by a stream of oil and gas which caught fire from his forge. As the flood of burning oil flowed down the river, he cried in terror, "I've struck hell itself. May God have mercy on me." Fig. 7 shows the first commercial refinery erected in California some 47 years later. Perhaps no more striking evidence can be given of the development of the oil industry than by comparing this first commercial refinery with Fig. 8, which represents the solvent refinery part of a petroleum distillery devoted to the improvement of its lubricating oil.

FIG. VI. BILLINGHAM WORKS.

FIG. VII. FIRST COMMERCIAL REFINERY ERECTED IN CALIFORNIA.

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Figs. 7 and 8.

In the early days of the industry the really desirable product was the kerosene, and in fact the companies concerned were often hard put to it to get rid of the petrol fraction. Little wonder then that the technique was so adjusted to cut down the latter to the very minimum, in fact at the beginning of the century the kerosene yield was about 75 p.c, petrol a bare 10 p.c. Since then the process has been so adjusted to meet the market that the yield of petrol has risen to 44 p.c, whilst kerosene was fallen to 6 p.c. One of the main alterations in effecting this is the introduction of "cracking," that is to say, the distillation of the crude oil is so carried out that the hot heavy liquid is broken down to a greater volume of simpler and lighter hydrocarbons which constitute petrol. With this increased production of light oil came other changes. The new petrol had a much higher Octane-value, i.e., a definitely reduced tendency to knock, so much so that the automobile engineer had to re-design his engine in order to take advantage of this new property. The steadily improving quality of petrol from the octane rating point of view has undoubtedly acted as a real stimulant to the engineer in his desire to obtain ever increasing speeds, both by car and by plane. By a process of which I shall speak later the commercial production of iso-octane itself is now accomplished, and still greater speed developments may be anitcipated. In fact not long ago a specially prepared 100-octane fuel was tested in an army plane, and gave 35 miles per hour more speed than a motor fuel of 92-octane number. Fuel consumption is being, reduced to such an extent by these improved petrols that it has been estimated that in a 14 hour flight from New York to Los Angeles a plane with a properly adjusted engine would need only 427 gallons of 100-octane petrol as against 555 gallons of 87-octane petrol, a saving in fuel of 25 p.c. or approximately 1000 lb. weight. But with the advent of cracking came other difficulties—the increased tendency to gumming. For a while cracked spirit was .rightly looked at with grave suspicion, until the chemist was able to discover that the addition of very small quantities of anti-oxidants into the petrol practically completely removed this tendency to gum or to oxidise. Step by step the engineer and the chemist have progressed in order to meet the public demand for more smoothly running engines, greater speed, greater reliability. Another oil product that has undergone similar changes is the lubricating fraction. Most car drivers have vivid recollections of the difficulties of starting the motor in heavy frosts, in fact under these conditions the so-called lubricating oil was really not a

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lubricant at all. This was due to the separating out of certain waxes which completely destroyed the film of lubricant in the bearings. Much pains were taken to remove these waxes by freezing them out, but the newer method now coming into full operation is to remove them by means of various solvents. This effects the physical separation of the molecules of high oiliness and tough film strength from those poor in these qualities. Solvent extraction plants are either in operation or in process of construction at all the main distilleries, and the motorist may soon expect more mileage per gallon and less wear on his engine. The main solvents used for this purpose are chlorex (dichloro-ethyl ether), furfural, propane and cresol, sulphur dioxide and benzene.

The latest tool of the oil technologist is what is known as polymerization—the building up of more complex molecules from the simpler—the antithesis of cracking. Under the action of heat such an unreactive substance as propane breaks down to propylene and ethylene, both of them highly reactive compounds from which many products may be derived. Incidentally, these light gases under suitable conditions of temperature and pressure produce more complex hydrocarbons forming an almost ideal motor fuel of very high octane number. In every oil distillery there are available millions of cubic feet of hydrocarbon gases (which were formerly burnt for the production of power), and furthermore, immense stores of these gases are also available in natural gas. It has been estimated that two trillion cu. feet of natural gas plus 300 million cu. ft. of refinery gases are yearly available for the purpose of polymerization, capable of yielding annually by the new process an additional 9 billion gallons of high quality petrol, i.e., 45 p.c. of the present annual total from the distillation plants proper. For the polymerization process two methods are available—thermal and catalytic. In the first the gases are sent through heated coils (1000' F.) under high pressure. The conversion into such unsaturated compounds like propylene is brought about by heat coils, whilst the effect of pressure is to convert these reactive substances into liquids suitable as oil fuel. A certain amount of the gases escapes reaction and circulates back to the plant. In the catalytic process lower temperatures (400° F.) and pressures (200 lbs. only) are employed. The catalyst, solid phosphoric acid, is packed in a series of towers through which the heated gases circulate and markedly facilitates the conversion. Eighteen gallons of petrol are procured from 1000 cu. ft. of gas with an octane number of 83, and an octane blending value as high as 132. Under specially controlled conditions iso-octane is made by this process.

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Just as coal and tar have long formed the raw product of the huge dye and chemical industry, so too it has long been the dream that a chemical industry may be built upon oil. During the past few years this has come to pass, and a definite swing-over of the chemical industry to the oil-fields of America is now under way. So long as the physical separation of crude oil into a large number of useful products of closely allied properties was the goal, nothing eventuated, for the mixture was too complex for such separation. The discovery that this mixture, both of oils and gases, can be readily broken down and resynthesised into any desired product has opened up a new line of attack. Just as around coal tar has grown up the coal-tar dye industry, so around oil is developing a major industry involving the production of numberless organic chemicals such as alcohol, ether, acetone, tetra-ethyl lead, acryloid resins, butyl alcohol, ethyl acetate, vinyl resins, synthetic rubbers and so on. An even more significant feature is the tendency to use some of the gases as a source from which cheap hydrogen may be derived for the production of fertilisers such as ammonium sulphate.

PLASTICS AND SYNTHETIC VARNISHES

One of the most important industries of the present day deals with the production of plastics or moulding powders, and closely allied with this, synthetic varnishes, gums and lacquers. An infant industry, born in 1907, it did not really assume commercial importance till after the War. Since then its development has been spectacular, so much so that the present age has often been referred to as the age of plastics. To mention but a few of the uses to which such substances may be put; we have synthetic gums capable of removing every trace of dissolved salt, acid or alkali, from water; table tops made from sawdust, aniline and furfural, and coated with a veneer of beautifully grained wood, fittings of the interior of cars made from soya bean meal plasticised with soya bean oil; an optical plastic glass eminently suitable for moulding into lenses which have all the properties of carefully ground lenses of optical glass; fabrics rendered creaseless by treatment with a plastic, others rendered waterproof; all types of electrical gadgets of high insulation and durability; lampshades, gramophone records, toothbrushes, internal house fittings, abrasive wheels, gears of cars, large chemical plant highly resistant to corrosive attack, food containers, non-shattering glass, varnishes and lacquers for motor cars, imitation new synthetic fabrics such as lanital, and so on.

The principle upon which the manufacturer works is to bring about such a change in the chemical character of

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the compound used, as to produce a complexity of molecule. After solidification the molecule or chemical unit may be 1000 times as large as ini the original powder, and this polymerization brings about a great change in physical properties-such as increased viscosity, hardness, inertness etc. Catalysts are used freely in order to control the rate of set whilst other compounds are often introduced in order to inhibit the development of some undesirable change for example bakelite is made from the action of formalin upon phenol (carbolic acid) but the resultant hard mass gradually darkens. For many purposes this was undesirable and the introduction of lactic acid as modifier was rendered necessary. As a result, this darkening has been prevented, and bakelite can now be coloured permanently to any desired tint. A useful type of plastic known as the alkyd resins is produced by the condensation together of glycerol or some similar alcohol with a dibasic acid such as phthalic acid. The resultant complex molecule develops a structure such as:

Fig. 9.

DIAGRAMMATIC REPRESENTATION SHOWING COMPOSITION OF GLYCEROL-PHTHALIC ACID RESIN.

where G stands for glycerol and P for phthalic acid. Bakelite has already been mentioned. When incorporated with a filler (asbestos, sawdust, flour, etc.) many new uses are opened up. Laminated sheets ot this material are being extensively used in theatre construction in fact houses are becoming increasingly decorated with plastics of the bakelite, vinylite type. Haveg. is an asbestos-bakelite mixture from which chemical plant is now being made, and owing to its lack of chemical reactivity is proving suitable for such purposes.

Fig. 10.

Pipe lines, too, are now being made of laminated sheets of synthetic resinous products, and for the handling of many liquids have a definitely longer life. The bronze propeller in a plant using zinc chloride solution was found to be consistently eaten out in 700 hours. The one made of a synthetic resin is still running after 12,000 hours. Even the metal industry appears threatened in certain phases by the new plastic materials.

FIG. X. PIPE LINE OF SYNTHETIC RESINOUS MATERIAL.

FIG. VIII. SOLVENT REFINERY PART OF A PETROLEUM DISTILLERY, DEVOTED TO IMPROVEMENT OF LUBRICATING OIL.

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The essential point in connection with the commercial development of a plastic is the cheapness of the raw product. The vinyl and acryl resins were first reported about IS 10. but they only become commercially possible where the coal distillation and petroleum refinery plants made available immense stores of unsaturated products such as ethylene. The same remarks apply to bakelitc which really assumed importance after the War when the American Government made available to industry 40 million pounds of phenol at 12 cents per lb. which had been acquired at a cost of 55 cents per lb. As an illustration of the type of problem the plastics chemist has to overcome, may be mentioned the case af the acryl resins. Methyl acrylate, when polymerised, is tough and elastic, stretching ' 1000 per cent, of its length before it breaks; the ethyl compound is still softer and more elastic. On the other hand methyl meth-acrylate gives a resin so hard that it will resist the blow from a hammer and in fact it can be worked freely on a lathe. At first it was hoped to get the desirable properties by blending resins of the two types of acrylate compounds in the forms of their various esters, but the result was unsatisfactory. It was. however, found that a mixture of the acrylates and the methacrylates could be polymerised or resinified together, forming a conjoint polymer which had just the properties required. This method of co-polymerisation or polymerising after mixing is now frequently used and gives a wide range of products. Different grades of vinylite are produced by a slight change in the original mix, suitable either for safety glass, or a lacquer or dentures as required. The urea-formaldehyde plastic is of recent discovery and now finds an increasing use for the production of creaseless fabrics, table ware, bottle caps, etc. Lanital, the new Italian synthetic wool, is a casein-formaldehyde plastic which has been made more manageable by the incorporation of a suitable plasticiser, enabling threads of suitable elasticity, etc., to be produced. The casein-formaldehyde compound has long been used for the production of buttons, umbrella handles and so on, but its adaptation to fibre production is a further step in the plastic world. Similar attempts to plasticise artificial silk in order to confer upon it properties closely associated with wool have already been reported, and there is really no doubt that before many years a synthetic fibre possessing the crimp and elasticity of wool will be on the market, in all probability produced by the action of a plasticiser on the cellulose fibre.

ARTIFICIAL FIBRE INDUSTRY.

A third modern industry that is having a far-reaching impact on the cultural and economic life of the community

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is that of the synthetic fibres. Thirty years ago artificial silk was almost a joke. The early product was admittedly harsh to the touch, and readily weakened by water. But whereas the silkworm is bound by Nature to produce its fibre under closely unalterable conditions, the methods of the chemist are subject to change. The early process has undergone modification and every step has been a step onward. In the early stages the standard size of yarn contained 12 threads; this rose progressively to 18, 24, 30, 40, 60, 90, 150, each increase giving greater opportunity for finer and more luxurious fabrics. Complaints too were made against the unduly brilliant lustre of rayon fabrics. This was first overcome by incorporating into the spinning solution small qantities of titanium oxide and other such compounds. This gave the dull, matt finish required, but the fibres were unduly heavy, hence the organic chemist has been called upon to produce inert synthetic compounds of good covering power, which can be produced of a uniform particle size. This he has done and the manufacturer can now control to the fullest degree the lustre of his fibre. The process of manufacture is very simple. Purified cellulose is converted into a soluble compound, which is then forced through fine nozzles in the spinneret to form threads. These are either coagulated by the action of some suitable medium such as acid, or in the case of the acetate the volatile solvent is evaporated away, and the residual coagulated cellulose acetate fibre remains. In the above wet process of coagulation the fibre is of cellulose itself. The rise in production of cellulose fibres has been astonishing. In 1913 the infant industry produced 24 million lbs. of fibre, ten years later this had risen to 100 million, last year saw the 1,000 million lb. mark passed, about a 1,000 per cent, increase in ten years. The original quest that led to the establishment of the rayon industry was a synthetic silk, but it was not long before it was realised that such a natural fibre was too complex a substance to synthesise readily, and hence the search developed for a substance which possesses many of the properties of silk. The research chemist has given us a unique fibre produced in greater quantity than silk itself, the first new fibre in 4,000 years. The great advantage possessed by a synthetic product is the uniformity with which it can be produced. Nature's products, on the other hand, are less uniform than man's, and they cannot in any way be modified in the making. The silk worm cannot control the lustre of its product, but the rayon expert can produce any lustre from metallic to chalky. The filament? may be finer than silk or coarser than horsehair, and the predetermined size can be maintained day in, day out. Surelv it is a unique performance to convert with absolute control a pound of

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rayon into a thousand miles of fibre alike in dye absorption, cross-section, size, lustre, and other physical properties.

Another great advantage which the chemical manufacturer generally possesses over the man who is using the natural product is the ease with which by a slight change in operation he can convert part of his main product into a different side line. Thus rayon can by a special process be treated so that it acquires a strength equal to a steel thread of the same dimensions. This new fibre is now being used in the making of tyre linings and will undoubtedly add several thousand miles to the life of the average tyre. Again, one of the forms of artificial silk, cellulose acetate, made by the action of acetic acid on wood pulp, can easily be converted into cellophane, now so extensively used for the wrapping of foodstuffs, into noninflammable films and into a flexible glass. Thousands _of tons of this material are also used as a plastic from which artificial tortoise shell, onyx, amber, fountain pens, etc., are made. It is but a short step to the production of an artificial leather in which a suitably coloured plastic mass of cellulose material is applied to a woven fabric of cotton, and then given the desired pattern by means of embossed plates.

RUBBER AND ITS SUBSTITUTES.

Closely allied to plastics is the rubber industry. For many years investigations into the composition of this substance have been going on, and to-day there are at least four synthetic rivals in the field., However, there seems little danger of serious competition except under certain unusual circumstances such as exist in the U.S.S.R. The main reason for this is that those in charge of the rubber industry have shown themselves possessed of real vision and have spared no effort to maintain the position of the natural product. As a result of biological research the yield per acre from plantations planted with the best available stock has risen from 400 to 1200 lbs. Every step is being taken to ensure that, in spite of the effect of such factors as the age of the tree, the season of the year, the rainfall and the soil, the biological liquid which flows from the tree is as nearly constant in composition as if it were made in a chemical factory. Furthermore, the manufacturer has introduced into the rubber small quantities of vulcanising accelerators which enable the vulcanisation to be carried out under more exact control than hitherto. Over-cured rubber is likely to become more and more a thing of the past. Then, again, in order to combat the tendency of rubber to crack when exposed to light and air, he has learned to introduce small quantities of anti-

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oxidants. Hence the good quality tyre has now an average life of 20,000 miles as against 8,000 m 1920.

The synthetic rubbers on the market aim at imitating the properties of rubber rather than its exact chemical composition. In Russia the country has for political and economic reasons been made almost entirely dependent on the artificial article, made from butadiene via the catalytic decompositions of ethyl alcohol. The cost of production is high as the conversion yield appears to be less than 25 per cent. Still, the output is increasing, 11,300 tons in 1934, 20,000 tons in 1935. The quality appears to be definitely inferior to natural rubber and to the synthetic American forms. Duprene, the chief U.S.A. synthetic rubber, is made from acetylene by a series of condensations with hydrochloric acid. The acetylene is first converted into mono-vinyl acetylene by means of the cuprous chloride catalyst. The mono-vinyl acetylene condensed with hydrochloric acid produces chloroprene (2 chloro-1, 3-butadiene), which on polymerisation gives duprene. Again the production cost is high, 12/- per tb., but in compensation for this duprene clearly surpasses ordinary rubber in its resistance to heat, oil, petrol. For certain special jobs where a tight, oil-petrol resistant joint is required, the additional price is no handicap, and large amounts of duprene are being sold for such special purposes. Owing to its being practically non-combustible it is also much favoured for electric wire insulation if there is any danger of fire. It has also been demonstrated that a tyre tread of duprene will give a 20 per cent, better result than the best rubber.

Another valuable rubber-substitute is thiokol. As in the case of plastics the essential step is the building up of large molecules by the linking together of simple ones, and with this polymerisation comes greater rigidity, and other changes in physical properties. Ethylene is the raw product, being first converted into the dichloride, and by condensation with the poly-sulphides of the alkalies a lengthy molecule results. Thiokol also undergoes a change analogous to vulcanisation. The change is effected by heating to 140 D C. generally in the presence of a curing agent such as zinc oxide. The earlier forms of thiokol possessed a highly obnoxious odour, but the newer modifications are much freer from this defect. The material is being extensively used for the lining of petrol hose pipes and similar purposes where resistance to oil and petrol is desirable. A somewhat kindred synthetic is A X F, made from ethylene dichloride by condensation with an aromatic hydrocarbon. The properties of A X F are very similar to those of thiokol and duprene, whilst its greater plasticity

Fundamental Operations of Segregating the Atmospheric Gases FIG. XI.

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enables it to find extensive use as a plasticiser for hard rubber, duprene and thiokol.

NITROGEN AND THE RARE GASES OF THE AIR.

Fifty years ago the atmosphere in which we live had little direct industrial use. It was Crookes who first directed attention to the growing need for nitrogen fertilisers of which there appeared to be a world shortage in sight. Soon after came the first commercial exploitation of liquid air, as a means of supplying both nitrogen and oxygen. Almost contemporaneously Ramsay undertook his brilliant investigation into the gases of the atmosphere. Aided by supplies of newly available liquid air, he was soon able to unravel the tangle as to the constituents of the air. His research showed that, not only does the atmosphere contain oxygen and nitrogen, with various adventitious impurities such as carbon dioxide, but that there were also present traces of certain hitherto unknown gases, argon, neon, helium, krypton and xenon. The delicacy of the experimental methods devised and used by Ramsay in the isolation and identification of these gases forms one of the epics of our science. He showed that air contains 0.94 per cent, of argon, one part in 65,000 of neon (1 lb. in 44 tons), one part in 200,000 of helium (1 lb. in 725 tons), one part in a million of krypton (1 lb. in 173 tons), and one part in eleven million of xenon (1 lb. in 1208 tons, or .00000002 per cent.). Small wonder that these gases should have escaped detection when present in such minute amounts, and, withal, when endowed with an utter lack of chemical properties. For twenty years these rare gases remained chemical curiosities, a monument to the unrivalled skill of one of the world's greatest experimenters, but recently several of these gases have assumed technical importance.

Fig 11.

Fig. 11 indicates how in the process of the liquefaction of air it is possible to isolate these gases and make them available for use. The light helium, generally isolated from certain natural gases, finds a use in filling airships with a non-inflammable gas, as well as for making a synthetic atmosphere for divers which enables the time of decompression on returning to the surface to be reduced to one half. Argon on account of its inertness is now introduced into electric light bulbs in place of nitrogen, thereby giving a greater efficiency. It is also used with other rare gases in luminous tubes, whilst rectifying tubes for delivering D.C. from an A.C. source also contain argon. Neon, so modest a constituent of the atmosphere, has completely altered the character of evening illuminations in every large

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city of the world. Its high electrical conductivity and light emission make it an ideal gas for advertising signs especially as its characteristic orange glow can be markedly altered by the addition of other gases. Krypton and xenon too may yet find a place in the electric light industry. The replacement of nitrogen by argon brought down the electric light bill of the U.S.A. by $125,000,000, and it has been shown that the use of a krypton xenon mixture would effect a further $200,000,000 annual saving. In viewing the academic discovery of Ramsay in retrospect one sees again a perfect example of the old story associated with the name of Franklin. When demonstrating to an audience a simple experiment which really gave Faraday the key which led to the development of the modern dynamo, he was asked by a bystander, "But of what use is this?" The scientist's reply was simple but crushing. "Of what use," he replied, "is a new-born child?"

In outlining Ramsay's work I have referred to the process of liquefying air. This is now a great industry, for nitrogen is required in thousands of tons for the production of synthetic ammonia. Some years before the War a German chemist succeeded in working out the conditions under which nitrogen can be brought into combination with hydrogen to produce ammonia. It took years of patient work to find the best conditions of temperature, and pressure, and the most suitable catalyst for effecting the conversion. Most of this synthetic ammonia appears on the market as sulphate of ammonia, a most useful fertiliser, whilst additional sources of nitrogenous manures are also bringing the nitrogen and oxygen of the air into combination as an initial step in the formation of nitrates. In 1913 some 7,000 tons of nitrogen were fixed in the form of ammonia, in 1928 this had risen to 400,000 tons. The development of the synthetic nitrogen fertiliser industry is best given in the statement that in 1914 Chile supplied more than 60 per cent, of the nitrogen consumed in the world, in 1924 this had fallen to 36.4 per cent., and by 1932 to 9.6 per cent. At the moment the world's annual producing capacity for synthetic nitrates and ammonia is nearly four million metric tons, whilst the maximum annual consumption of nitrates from all sources is less than two million tons. Prices of these commodities are therefore, never likely to rise much above present prices.

INDUSTRY AND PHYSICAL RESEARCH.

The world of science is a very complex structure, each science dove-tailing one into the other, each ever ready to help a sister science in difficulty. To physics in particular the world owes a deep debt for the extraordinary precision with which methods of measurement, devised by the

FIG. XII. PHOTO-ELECTRIC CELL, CONTROLLING AUTOMATIC MACHINE FOR CUTTING WRAPPERS.

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physicist, enable effective control of temperature and pressure to be maintained in chemical industry. The extreme sensitiveness of modern methods of physics can best be illustrated by a few illustrations. Thus if a sixtieth of an ounce of radium were equally divided among all living human beings, the physicist would have no difficulty in detecting whether a particular individual was actually in possession of his share. Methods of precision have enabled him to determine with uncanny accuracy the infinite number of molecules present in any given volume. If a tumblerful of water is poured into the sea, and in the course of time this becomes uniformly distributed throughout every river, lake and sea, and if a tumblerful of water is then dipped out of any such river or sea, the physicist has taught us that it will contain no less than 1000 of the molecules originally present in the tumbler. One more example. If an ordinary electric light bulb be taken and a tiny hole made in the side just large enough to let through a million molecules per second it will take a million years before the bulb is filled with air at atmospheric pressure. These examples show us the extreme accuracy with which measurements of all kinds can now be made whether in purely scientific or in industrial undertakings. Most of us are aware of the light sensitive cell, the current from which varies with the strength of the light falling upon it. Until comparatively recent times such a cell was an object of interest and wonder, to-day many industrial operations are automatically controlled by it. In an up-to-date freezing works an accurate count of the number of carcases is made by an automatic record of the number of times the carcases interrupt a beam of light falling upon the cell, each such interruption causing a change of current which is registered. Fig. 12 shows a photo-electric cell controlling an automatic machine for cutting wrappers in a factory.

Fig 12.

Wherever a decrease in intensity of a colour can be effected, such a photo-electric cell may be usefully employed. Many exceedingly sensitive analytical methods depend for their effectiveness upon the accurate measurement of colour intensity. An illustration lies close at hand. The very fine work which the Cawthron Institute has done in disentangling the role played by cobalt in the animal metabolism depends upon the accurate estimation of small amounts of cobalt in pastures, soils and animal organs. This has been done by converting the cobalt into a coloured compound, and an estimate made of the depth of the colour. But whereas Heinz has found it worth while to control his machines by means of a photo-electric cell, it has not been possible for the staff to use such a ready means for the

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rapid estimation of cobalt required in the course of their work A generous gesture from a friend of Canterbury College has brought such an instrument into our hands, and I commend to the many well-wishers of the Cawthron Institute the suggestion that this and other instruments would make the analytical work of your staff more rapid and effective, and aid materially in carrying out that very fine research work in the field of Animal Health which has recently brought to the Cawthron Institute world-wide praise.

SCIENTIFIC CONTROL IN INDUSTRY.

In chemical industry the principle of automatic control especially of such factors as temperature, pressure and humidity is in everyday use, but recently conductivity cells and other devices of this nature have come into their own. A remarkable example of automatic control of chemical plant is its application to solvent recovery in the Shoe Industry. The process involves absorbing a mixture of acetone and hexane in activated carbon, then comes the recovery of the mixed solvent by steaming, the separation of the hexane, and finally the fractional distillation to recover the acetone from the water. The plant is entirely under automatic control. The attendant merely starts up in the morning and switches off at night. Fourteen valves supplying air, steam and vapour are automatically controlled by water pressure as the result of changes of temperature, steam pressure and the rate of flow of steam and air. A time-switch effectively controls the correct sequence of operations.

A little over two years ago a large chemical factory in the States turned its attention to the commercial separation of bromine from sea-water. True, the amount present is almost infinitely small, 67 parts per million, but they have achieved success. A suitably situated spot on the East Coast of America was chosen where the intake was sufficiently removed from the effluent spot, and the sea-water is passed through the bromine extraction plant. About 26,000 gallons of sea-water per minute are forced through the plant, and 15,000 lbs. of bromine extracted per day. By the application of automatic control throughout the plant the process has been made a commercial success—an interesting example of securing traces from tons practically without the aid of a workman on the plant.

BOTANICAL RESEARCH.

One interesting example of the impact of science upon civilization may be chosen from the biological side. The introduction of the potato to Europe was the result of the action of a sea-farer, not a botanist, and was of an entirely

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random nature. From this limited material all our present day varieties have sprung. A few years ago a group of Soviet scientists visited Central America in the hope of finding new varieties of potato which might be useful for plant breeding purposes. They combed the district from the equator to 40° S., from sea-level to the snowline, and found as they expected many new varieties quite different from the European cultivated potato—in all 15 new cultivated species and thirty new wild species. One species is resistant to wart-disease, another to blight, a third will tolerate 14° frost without incurring damage, a fourth is rich in protein and very low in starch. These new species open up new avenues of development in potato culture. A few of these potatoes are in New Zealand, but steps are under way for a big Empire expedition to visit the same area in order to secure fresh plant-breeding material. Several species too, are short-day forms, i.e., will form no tubers under ordinary conditions of cultivation in the temperate zone, unless steps are taken to control the length of the day. These varieties may prove a great boon to tropical countries such as Kenya, India, where the potato is not at present available as a staple article of diet.

CHILLED BEEF INDUSTRY.

About fifty years ago Professor Linde, of Munich, laid the foundation of the modern commercial developments of refrigeration in his invaluable memoirs on the theoretical aspects of evaporation and condensation. What refrigeration has meant to New Zealand in the past I need not dwell upon, but I do remind you that this work is continuing. The Low Temperature Research Station at Cambridge has in very recent years perfected the process whereby chilled beef can be sent overseas from Nw Zaland and Australia and landed in really first class condition. This is done by the use of a synthetic atmosphere, containing roughly 10 per cent, carbon dioxide, this preventing the development of moulds, etc., at the chilling temperature. And here is the commercial response. In 1933 New Zealand sent home 1,600 cwt. of chilled beef, in 1934 33,400 cwt, in 1935 110,600 cwt., and in 1936 up to July 159,000 cwt. Similar work is going on in order to improve the transport of apples and it should not be long before our first commercial shipment of fresh asparagus is sent overseas, to land at a time when the ruling price under present conditions is in the neighbourhood of 7/6 to 10/- per bunch.

SCIENCE AND CIVILISATION.

Finally may I refer to the charge often levied against science that the world would be the better had many of the inventions and discoveries of recent years never been

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made. It is true that, as the result of scientific discoveries, there have been sudden and at times catastrophic changes in the labour situation. Thus the magnetic crane, worked by one man, can lift in one operation a load of pig iron which formerly had to be moved, pig by pig, by the muscles of 60 brawny men. One brick making machine will make 40,000 bricks per hour, once made at the rate of 450 bricks per day per man. But on the other hand new industries have sprung into existence at the call of the scientist and the engineer, for example the automobile industry which in itself probably employs at least 20,000,000 workmen throughout the world. An invention is just what we make of it. To the statesman must be left the task of integrating scientific discoveries into industry so as to give the maximum benefit to mankind. Not long ago a prominent scientist wrote: "For the first time in the world's history man has gained, through the advance of science and its application, the capacity to produce and to distribute more food than he can eat, more clothes than he can possibly wear, more automobiles than he can possibly ride in ... . Modern science has shown us how to load a large part of the grinding labour upon the backs of the soulless, feelingless machines to such an extent that, though routine things will still have to be done by us, yet the productivity of that labour is so great that the leisure for higher things is now a possibility for everyone." The coming of the machine and of scientific control should be a glorious blessing to mankind provided society will exercise as much intelligence in fashioning them to their aid as engineers and scientists have given to the conception of their intricate discoveries. To the charge that our civilisation as expressed in terms of scientific achievement has been grossly materialistic, allow me to quote in conclusion the words of an eminent Chinese philosopher, Hu Shih. "To me," he said, "that civilisation is materialistic which is limited by matter and incapable of transcending it, which feels itself powerless against its material environment, and fails to make full use of human intelligence for the conquest of Nature, and for the improvement of man. On the other hand, that civilisation which makes the fullest use of human ingenuity and intelligence in the search for truth in order to control Nature, and transform matter for the service of mankind, to liberate the human spirit from ignorance, superstition and slavery to the forces of Nature, and to reform social and political institutions for the benefit of the greatest number such a civilisation is highly idealistic and spiritual." This I claim is what Science has done for mankind.

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