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nation or group of nations to arm themselves to such an extent that it or they can become a menace to the peace of the rest of the world.

Organisation.

There is another and more positive lesson for us in the present war. It shows the power of organisation. We see two Empires, but roughly one-the Germanic nation-at war with four other great nations, which has so developed its resources and organised them, that it can stand the strain of such a war that 25,000,000 picked men have already been in the field. However deplorable this may be from ethical and economic points of view, it at least does show what science and organisation can do to-day. I suppose that, one way and another, 50,000,000 of the human race are either fighting or supplying food and munitions of war to the combatants. And no sign of exhaustion is as yet clearly discernible. When we remember that war in the olden days was conducted with small armies and only during a portion of the year, we realise the maleficent power that science has placed in the hands of mankind. It needs careful regulation. This power for evil might only have been potential, it might have remained undeveloped; but we have found to our loss that at least one nation has developed and organised itself, by the aid of science, to such an extent that it dares to declare itself independent not only of the power, but even of the opinions of the rest of the world.

The lesson will not be lost. If the deliberate organisation of a single nation can result in such power, then every nation must organise. Not necessarily organise for war, for death; but organise for peace, for life.

Laissez faire passed into twilight when the great war commenced. We have to turn our eyes in the direction of the rising sun of an organised humanity, of which we perceive the dawn already. Then the advancement of science will surely have no sinister meaning. We pray that the advancement of science will be identical with the advancement of humanity.

Progress of Astronomy.

I am perhaps fortunate in belonging to a branch of science which has nothing to do with war. Therefore the astronomer can regard war with a sense of detachment; and to those who know the stars, the immensity, the eternity of the universe, its increasing grandeur, war seems trivial and foolish-the work of unbalanced minds.

I spoke of one of the aims of science as the enlargement of the human mind. Although every branch of knowledge-a word which I take to be nearly synonymous with science (science being co-ordinated knowledge)-leads to the extension of the human mind, today astronomy has no other real use. We know that clocks are corrected through the observations of the stars, and that the sun and stars must be observed by navigators, but preparation for these practical applications forms a very trifling portion of the activities of astronomers. The very perfection of that part of astronomy reduces it to a sort of automatism-it all but goes by itself. To-day the astronomer wants to find out the dimensions of the sidereal system-the extent of the universe-the structure and arrangement of the stars in space-their relations to each other-the interpretation of their spectra-the dynamics of the universe the cause of variable stars. The solutions of any or all of these questions can scarcely have any material effect upon mankind-the effect is spiritual and emotional-man is proud to find that he can plumb space to its uttermost depth; he presumes that the germ of the future which was conceived in the past

is taking its form to-day, and that the process is continuous, and that as to-day he can predict tides and eclipses, so with greater knowledge he will in the future be able to predict the course of the sun amongst the stars and the future conditions of the planet upon which he has his being.

The Distances of the Stars.

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The problem which will be more closely discussed in this address is that of the distance of the stars. The most direct way of finding these is by the parallactic displacement of the stars caused by the motion of the earth round the sun. In this inquiry the Union can have a local pride, as the first parallax 2 certainly found was that of a Centaurus by Henderson, the Cape Astronomer. The late Sir David Gill, our first president, continued Henderson's work, and perhaps one might say finished it in that form. Gill was an organiser, and when the parallax campaign, initiated by himself and completed with the aid of Dr. Elkin and others, had come to an end, it was apparent that the most direct method of finding parallaxes which was available would only yield a small crop, because the stars are at such enormous distances from the sun that the available base-line for measurement, the diameter of the earth's orbit, some 186,000,000 miles, or 300,000,000 kilometres, is vanishingly small at the distance of all but a few near stars. a Centaurus is the nearest known, and almost certainly the nearest to the sun, yet at its distance the diameter of the earth's orbit subtends an angle of but seconds of arc-an angle which is described by the minute hand of a clock in a four-thousandth part of a second of time. An angle so small is difficult to observe directly with accuracy, so that at best the measures must become differential-that is, the stars are measured from neighbouring stars supposed to be at a much greater distance away; such stars are called comparison stars.

Prof. Eddington estimates that there are thirty stars with a parallax of 0-20" or greater, of which nineteen are already known. This means that within a distance nearly four times as great as that of a Centaurus there are but thirty stars in all. This is the limit of visual work such as was done by Gill, but photographic methods, especially with the enormous telescopes used in America, carry the direct attack further.

The delicacy, or, if you prefer, the accuracy, of any measurement is limited by its probable error. The probable error of a parallax measured visually under good circumstances (such as with the Cape heliometer) is about 0.10" (a tenth of a second of arc), and this is already, small as it is, a quantity larger than the quantity to be measured except in the cases of a hundred or so stars. The same method of parallactic displacement of stars on photographic plates has a much smaller probable error. The most recent determinations made with the great telescopes of America, and in particular the 40-in. refractor of the Yerkes Observatory, have a probable error of about o-01", or ten times less than the usual visual method, and Dr. Van Maanen, using photographs taken with the 60-in. reflector of the Mount Wilson Observatory, has reduced this probable error to 0-006", or about a hundred and seventieth part of a second of arc. As regards the measurements of small quantities, this is a wonderful achievement, but delicate as these measure

2 But not the first announced. Bessel in 1833 announced the measurement of the parallax of 61 Cygnus two months earlier than Henderson, whose delay was caused by his removal to Europe.

3 The only direct parallax found was that of a Centaurus, by Henderson. All other parallaxes of any certainty depend on an indirect method involving the assumption, nearly true, that all the stars with a few exceptions have very minute parallaxes.

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The negative parallax in Van Maanen's list would mean that the star was actually more distant than its comparison stars, which is at least unlikely, and in two other cases it will be seen that the parallaxes found are smaller than their probable errors. Somewhat similarly, in the case of 61 Cygnus, although the two parallaxes found agree very well, they differ by much more than their probable errors.

(3) In the recent most considerable list of stellar parallaxes published (Slocum and Mitchell, Popular Astronomy, March, 1914), out of twenty-eight results, eight are negative parallaxes and another four are smaller than their probable errors; yet the list is one of stars selected for large proper motion or some other peculiarity which indicated a measurable parallax.

These three sets show us that, valuable as the photographic method is, it is to be feared that it will also soon work out its rich lodes. So it does not take us much further. In this way the direct attack by parallactic displacement will reveal perhaps some one or two hundred parallaxes; but we would learn nothing as to the distances of the great mass of stars, except what we already know, namely, that the distances are tremendous.

Fortunately there is an indirect method of attack which, in the course of time, will tell us the distances of all the stars.

Basically this method depends upon a knowledge of the proper motions of the stars. If by its annual motion around the sun, the earth causes the stars to be displaced, it is obvious that the progressive motion of the sun through space must cause a progressive displacement. If for the moment we assume the stars to be at rest, they will seem to suffer two displacements-one purely periodic in a year, the other progressive, due respectively to the earth's orbital motion and the sun's motion through space.

The earth's orbital motion being periodic has no cumulative effect, but the sun's progressive motion is cumulative. The amplitude of the earth's periodic motion is about 300,000,000 kilometres, and all the best and most recent results show that the sun is moving through space with a velocity of about 18 kilometres a second; hence in a year the sun, and with it, of course, the earth and the rest of the solar system, move over a distance of 550,000,000 kilometres; roughly this is already twice the earth's annual displacement, and, as already stated, it is cumulative; thus, in six years, the progressive displacement is already eleven times the earth's periodical displacement, and the gain is continuous. Hence the mere lapse of time will tell us the distance of the stars, but the problem is complicated because the proper motions

of the stars are not mere reflexes of the sun's proper motion; the stars themselves are also in motion, so that a process of unravelling is necessary. Without any unravelling, but by simple averaging, the elder Herschel found that the sun was travelling in the direction of the constellation Hercules. At Capetown, in 1905, Prof. Kapteyn announced his discovery that the proper motions of the stars divided themselves into two distinct drifts. The elder Boss found that the proper motions of a widely-spread group of stars converged to a point. The same astronomer also found, from a study of the proper motions, that there was a marked relation between the amount of proper motion and a star's spectrum.

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Investigations based upon proper motions-the thwart or across the line of sight motions—were powerfully aided by spectroscopic results, especially by the application of the Doppler principle, which tells us almost directly the radial velocity of the star, or its motion in the line of sight. The interpretation of stellar spectra is far from complete, and its problems will not be discussed to-night. The broad facts are that stellar spectra, with a few exceptions, fall into four great classes, which may be called the helium stars, the hydrogen stars, the metallic stars, and the carbon stars, in which the gradation from one class to another is so well marked that it is very plausibly assumed that a star of one class can in the course of time change into its contiguous class, and from that into its next class. At present it is assumed that the helium class is degrading or cooling into the hydrogen class, and that the hydrogen class is similarly approaching the metallic class (in which our sun is), and that later the metallic class will degrade into the carbon class, and that, finally, the carbon class will cool down and become dark stars. This continuous degradation is a convenient memoria technica, but it is not based upon any facts. Sir Norman Lockyer, by a closer study of spectra, asserts that there is both a descending and an ascending scale. The assumption that there are the dark stars above referred to is unsupported by any fact. But to-night we are only concerned with spectrum analysis as an aid to interpreting the proper motions of the stars. Radial velocities fully confirm the motion of the sun through space as disclosed by the proper motions. The recent spectroscopic determinations of the direction and amount of the solar motion made by Dr. Campbell in America and by Messrs. Hough and Halm at the Cape, agree within a reasonable margin with the determinations of Newcomb and Boss, which are based on proper motions. Further, as with the proper motions, it is found that as the stars degrade from helium to hydrogen to metallic to carbon spectra, their velocities increase. Prof. E. C. Pickering and others have shown how certain species of stars aggregate in certain parts of the sky. Thus the helium stars are only found near the Milky Way, that great girdle of stars which is the framework of the sidereal system. The direct measurement of parallaxes, and the smallness of their proper motions, both indicate that the helium stars are enormously distant; and conversely, that stars near us are generally of the metallic spectrum class. Besides the Taurus group of converging stars found by Boss, several other groups, with members spread all over the sky, have been found. The stars in these groups appear to be moving with nearly equal and parallel velocities through space. It is evident that once a star is grouped correctly, and the parallax or distance and velocity of any one star in its group is known, we can also determine its distance. Unfortunately the Doppler principle, by which astronomers determine the radial velocities of the stars, is somewhat limited in its application. In the helium and hydrogen classes the lines of the spectrum are

few and are difficult to measure, and in all classes it is only possible to measure the displacements of the lines of the bright stars. Even if we anticipate improvements in the art of spectrography, it would seem impossible to obtain spectroscopic data in the form required for more than twenty or thirty thousand of the brighter stars. Therefore, although spectroscopy will be a useful ally, its help is limited.

Let us now collect the data which are at the astronomer's disposal for finding the distance of the more distant stars. The most important datum is the star's proper motion. This is compounded of the reflex of the sun's motion and of the star's own proper motion, which latter may be eliminated by a process of judgment by assuming that the star is an average member of its group and spectral class, or that it belongs to one or other of Kapteyn's two drifts. Although in individual cases these indications may be very erroneous, yet in the gross they are permitting astronomers to classify the stars into manageable

groups.

What is wanted is a better knowledge of the proper motions of the stars. Unfortunately at present these are not well known except for perhaps 10,000 of the brighter stars. Hitherto, the finding of the proper motions of the stars has been slow, arduous, and expensive work. At least ten meridian observations, spread over half a century, were essential, and each meridian observation cost about 20s., and meridian observations can only be made of the brighter starsof perhaps 100,000 out of 1,000,000,000 stars now within the reach of the largest telescopes, or of one star in every 10,000. This proportion is altogether too onesided. Hence astronomers hailed the advent of the photographic dry plate. An organisation for a Carte du Ciel was formed, in which our first president, the late Sir David Gill, was one of the chief promoters, and this scheme has now been at work for twenty-eight years; but, so far, the first Carte is far from complete. When completed in ten or twenty years' time, we may expect it to furnish us with precise positions of some 3,000,000 stars (or of about 1 star in 300, still a very small proportion). We will not know the proper motions of these stars. To achieve that, another Carte du Ciel must be prepared, so that we must expect another half-century to elapse before we are in possession of these 3,000,000 proper motions. Again, the labour, and with it the cost, involved is enormous, and will probably be in the neighbourhood of 10s. a

star.

The drawback to these two methods of obtaining proper motions is the necessity for defining the exact position of each star at different epochs, whilst what we want is not its exact position, which is difficult to define, but its change of position-that is, its proper motion. At the beginning of this century it had been suggested that there was no necessity to measure the places of all the stars on photographic plates, but that if pairs of plates were examined in the stereoscope. those stars which had moved relatively would stand out in relief; alternatively, that if pairs of plates were superimposed, those stars which had moved by proper motion would easily be picked out. These suggestions were tried, and led to the discovery of a few proper motions, but the method was not workable on a large scale, mainly because of fatigue or strain upon the eves. A third alternative was discovered by Dr. Pulfrich, of Jena, and described by him as a blink method. By this method the pair of plates to be examined is placed side by side, like the pictures in a stereoscope, but they are examined with one eye through an optical and mechanical arrangement which rapidly lets the eve rest first on one plate and then on the other, so that in one second the eve has looked This at each plate separately three or four times.

blinking makes the eye wonderfully sensitive to the slightest shift upon the plates. If one star relatively to its neighbours has shifted a hundredth of a millimetre upon a Carte du Ciel plate, the change is not only unmistakable, it is obtrusive. This blink-method revolutionises astronomy of position as regards the stars. Both with the meridian observations and the Carte du Ciel measurements, each star had to be dealt with separately. In the blink method the stars are dealt with in groups. Indeed, one can say that it is easier to deal with 1000 stars by the blink method than with one by the other methods. All that the blink method requires is pairs of plates separated by as long intervals as possible. A few weeks ago Mr. Hough (H.M. Astronomer at the Cape) placed in Mr. Voute's and my hands a pair of plates with a time interval of nearly twenty-three years. There were about 10,000 stars on the two plates; in a few hours we were able to announce that only twenty of these showed proper motion-the rest were fixed stars-and we were able to find the proper motions of many stars which were so faint that even the great Carte du Ciel would not have included them. Since then further pairs of Cape plates have been placed at my disposal with intervals of sixteen to eighteen years; the results confirm the earlier experience. We can therefore clearly state that astronomers have now a weapon of attack which will in the course of time reveal to them, without arduous or expensive labour, the proper motions of all classes of stars from the brightest to the faintest. This will lead to a knowledge of the structure of the sidereal universe which a few years ago seemed unattainable. The immensity of the task when tackled by the old methods seemed so great, and the consequent delay so inevitable, that Kapteyn proposed that astronomers should concentrate their attention on certain selected areas which might be taken as representative samples of the whole sky.

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A rude analogy will perhaps help us. The old way was something like studying the condition of England by means of a Burke's Peerage" or a "Who's Who." Kapteyn proposed as better a limited number of selected areas, some urban, some rural; but the blink method, will easily cover the whole area and permit an exact census to be taken.

The present state of astronomical science is one of great activity, but I have only time to make some brief references. The activities of the Union Observatory, an institution originally started by our association, call for some mention. The late Mr. FranklinAdams planned a photographic chart of the whole sky, and more than half of the plates were taken at the Union Observatory. These were forwarded to the Astronomer Roval at Greenwich, and are undergoing examination. Some of the first results of this examination have been published in the Memoirs of the Royal Astronomical Society. Counts of the stars on these plates have been made by Messrs. Chapman and Melotte, from whom the following figures are taken :

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ing the total number of stars in the sky, arranged universally applicable we see in the solar system in according to magnitudes :

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So actually, the Franklin-Adams plates locate for reference at any time about 100 million stars, and these may be said to be all the stars known to astronomers. Special plates taken with the largest telescopes indicate a much larger number of stars-perhaps ten to fifteen hundred million in all. It will be noticed that the ratio from one magnitude to another, which is larger than 3 at the beginning of the table, progressively decreases, and is already less than 2 for the 15-16 magnitude; hence the authors conclude "that modern photographic telescopes penetrate to a distance at which the stars begin to thin out fairly quickly either really or by absorption."

Variation of Latitude.

Since March, 1910, and until December, 1914, the Union Observatory has, aided for some years by a subsidy from the International Geodetic Bureau, taken part in a scheme of observations for measuring the variation of latitude. I must be brief, and will only say that the question at issue was: "Is this variation common to the whole globe, or is it in part or wholly due to the elasticity of the earth, so that the deformation in the northern hemisphere might be different from that of the southern hemisphere?" The result of our observations to March, 1913, proves that in the variation of latitude the earth moves as a solid. In Dr. Albrecht's own words :

"From this series of observations we can deduce an interesting confirmation of the result, previously obtained, that the values of the quantities x, y, and z deduced from observations made in the northern hemisphere, can be applied without any modification to the variation of the latitude in the southern hemisphere." 5

Gravitation.

For upwards of half a century it has been known that the law of gravitation seems to be insufficient to account for all the planetary motions-the most conspicuous exception being the motion of the perihelion of Mercury's orbit-and it has been found more recently that it is impossible to reconcile the moon's motion with gravitation. Recently Sir J. Larmor and Mr. H. Glauert have proved that a certain amount of these irregularities are due to variations in the length of the day; Glauert finding that the length of the day has increased by a hundredth of a second in a third of a century. This means that as compared with a third of a century ago, the year will appear to be about 3 seconds longer. Such a change, because of our methods of determining time, will be most clearly reflected in the motion of the first satellite of Jupiter, the eclipses of which can be observed with an accuracy of about one second, and the motion of which is the most purely periodic that is known. Since 1908, every visible eclipse of this satellite has been observed at the Union Observatory, so that in the course of time we may expect that our observations may assist in the solution of an obscure problem. In dealing with the structure of the sidereal universe, or in a smaller way with the dynamics of a starcluster, it is often tacitly assumed that gravitation is the only force at work. That gravitation is not 5 Rapport sur les Travaux du Beau Central en 1914, p. 6.

the phenomena of comets' tails, and even more so in the disintegration and disappearance of periodic comets such as those of Biela and Holmes. Many double stars are undoubtedly subject to the law of gravitation in all its purity, but in far many more gravitation appears to be at most only a secondary (thus in the case of double stars of which both components are of the helium type, there do not appear to be any signs of gravitative action between the two stars). It is true that stars with variable radial velocities have been found spectroscopically, and their orbits deduced by purely gravitational principles, but in many of these cases it is not indubitably certain that the shift in the lines of the spectrum is due to recession or approach. The difficulty is that in the so-called earlier type of stars, it is found that the H and K lines of calcium do not share in the variable motion on which the binary orbit is based. The interpretation of spectrathe contradictory behaviour of different lines, their thickness and intensities-still provides problems to be solved. In this connection one must refer to the illuminating papers by Dr. Nicholson on the relation between atomic structure and the lines in the spectrum. Nicholson's work makes much use of the spectra of nebulæ, in which we see matter under simpler conditions than is possible on earth. At this meeting Prof. Malherbe is reading a paper upon Atoms, Old and New," which will go further into this subject than is possible here.

Organisation of Astronomy.

In the earlier part of this address I dwelt upon the power of organisation under scientific direction. I am tempted to develop the subject, limiting my example of organisation to the science of astronomy, which is truly international in its aims. Astronomers are scattered all over the world, and pursue their work independently of the people amongst whom they live, and who provide the money necessary for their existence. The people are not ungenerous, but they cannot be critical. The astronomer is on his honour as it were, and this is nearly good enough, but not quite. If the astronomer is a man of sufficient initiative and energy with a regulated imagination, he will not require much supervision, but he may feel that without the co-operation of his colleagues spread over the world his work may be one-sided. He sees the need for organisation, and such organisation is not quite unknown, and has been found beneficial. Such occasional events as the transits of Venus and total eclipses of the sun generally lead to some loose co-operation. More organised affairs were the Star Catalogue of the Astronomische Gesellschaft (a society having its headquarters in Germany, but with international aims). It divided the sky into zones, and allotted these to certain observatories, which were willing to co-operate. The catalogues actually published have been contributed by Austria, England, Holland, Germany, Norway, Sweden, Russia, and the United States. This organised efført, started in 1858, is still going on. The other and more important organisation is that of the Carte du Ciel, started in 1887, and in which our first president took a leading part-he was connected with it from its inception, and when he died he was the president of the Commission. The scheme for the variation of latitude observations is also an international organisation. All these organisations were voluntary. In every way they were useful. The problem is whether we can extend the organisation to the whole body of astronomers, and yet not destroy their initiative. A control, however light, which would destroy initiative would be fatal. At present many observatories furnish annual report. Thus the Royal Astronomical

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Society in London publishes reports from most of the observatories in the Empire; the Astronomische Gesellschaft does the same for all the German, many Continental, and a few American observatories; the French Government publishes the annual reports of all French observatories. Other observatories furnish annual reports to their own Governments or controlling bodies, and some of these are printed and circulated. Still other observatories, and these in no small number, publish no reports. The change I advocate is a very small one; it is that every observatory should furnish an annual report to its authority, and that these authorities should transmit the reports to an international association of astronomers, for comment and return. The report should be divided into sections somewhat as follows:-(1) Working staff of observing astronomers, non-observing astronomers, comprising computors and ordinary assistants; (2) detailed list of instruments which cost more than 250l. apiece; (3) how many observers have permanent quarters in the grounds? how many non-observers have ditto?; (4) efficiency of those instruments in past years in percentage of hours available for work; (5) observations secured in past year; (6) observations published, being prepared for publication, etc.; (7) unpublished observations made in previous years reason for non-publication; (8) projected lines of work; (9) general notes and explanations.

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All these reports should be examined and analysed by a committee of the international association and then published. The committee would then make its suggestions to the controlling bodies, leaving these to act on them or not. In this way the careful minister or even the conscientious member of Parliament could find out the opinions which an expert body holds concerning the institution for which he is asked to vote money. The advisory body could suggest to those astronomers who have sufficient equipment, but make no use of it, useful lines of research. The ardent astronomer who cannot persuade his Government to provide funds would find himself in a stronger position when he has behind him an international body. lethargic astronomer would find that his colleagues elsewhere look to him to do his share. Better than all, it might be possible to arrange that research students could visit and work at observatories the equipment of which is not in full use. It would be invidious to give examples of observatories not working up to their potentialities-few can-but several make no attempt at any work, and have become little better than sinecures it must suffice to say that at least two of the observatories possessing exceptionally large refracting telescopes have not contributed one month's work from them in the last twenty years-their expensive equipment is idle and slowly deteriorating-the output from many others is disappointingly small. If some international association had the power to recommend that these great telescopes were put into commission, or, better still, to assign research students to their use, it would be a good thing.

In ancient days princes and men of wealth founded religious institutions called abbeys and monasteries. They did so because they considered they were helping the cause of humanity-and for centuries these bodies did respond to a real need-but the need passed, and only effete institutions remained-ultimately to be swept away-and to-day princes and men of wealth do not found abbeys. In modern times-the most ancient observatory is not old-princes and men of wealth found observatories because they consider they are helping the cause of humanity. It is unnecessary 6 They may provide a time or meteorological service of some local importance, but as institutions for research work of any kind their efforts are negligibly small. At least 33 per cent. of the observatories listed in the Nautical Almanac publish nothing.

to push the analogy. The ardent astronomer will not permit it to be pushed too far; he will organise with his colleagues for the advancement of his science, and the consequent enlargement of man's intellectual horizon.

I have only dealt with the organisation of a branch of science somewhat widely detached from the current activities of the world. It would have been too ambitious to sketch the organisation of a State or of humanity at large. But such organisation must come. The war every day is showing us how necessary it is to organise for production-even if only in the munitions of war-and not for profit. We are living in dangerous times, times in which it behoves the man of science, who is actuated by no selfish interests, to exert his power in remoulding the new society when the time, now near at hand, comes.

The notable discussion in the House of Commons on May 13 last (reprinted in NATURE of May 20) on the motion of the Government to form an Advisory Council on Industrial Research, sets an example, which is sure to be followed by other British communities. All the debaters spoke of the extraordinary example of Germany rising to great material power through the spread of technical education and scientific research. No country can afford, or would be justified, in lagging behind, but a more ethical objective should be the ideal.

In South Africa several problems have suggested themselves, but the experimental work would be very costly, and might, after all, be insufficient, so that their solutions do not appeal to private enterprise. The local production of liquid fuel is one of these problems. Liquid fuel can be made both from lowgrade coals and from agricultural produce, and it is within the range of probability that what to-day are considered noxious weeds, such as the prickly pear, might have an economic value in the production of alcohol. Again, the extraordinarily favourable duration of sunshine in the Union invites the trial of sunpower boilers, especially for pumping. A census of the water power "white coal" is also desirable, because if we have no great falls of water excepting the Victoria Falls, we must remember that our high veld rivers have a descent of 6000 ft. to sea-level, some of which is probably economically available.

If science is co-ordinated knowledge, what is the man of science? The true type is a man of faith, believing in the power of co-ordinated knowledge to make the world a purer and a better one. If the object of science was only the material conquest of nature it would be unworthy, and sooner or later it would be rejected by mankind. The faith of the man of science is unlimited-he might declare his creed in words somewhat as follows:—

"I believe in the ultimate distinction between Good and Evil, and in a real Process in a real Time. I believe that it is my duty to increase Good and to diminish Evil. I believe in doing so I am serving the purpose of the World. This I know and I do not know anything else; I will not put questions to which I have no answer, and to which I believe no one has an answer. Organic Action is my creed, Abstract speculation weakens Action. I do not wish to speculate; I wish to act; I wish to live."

Or, he says, using the words of Bacon:

"The knowledge of Truth, which is the Presence of it; and the Beleefe of Truth, which the Enioying of it; is the Soveraigne Good of Humane Nature. The first Creature of God, in the workes of the Dayes, was the Light of the Sense; The last, was the Light of Reason; And His Sabbath Worke, ever since, is the Illumination of His Spirit."

7 Adapted from "Appearances," by G. Lowes Dickinson (1914).

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