Science at the Front

“All the scientific work of the country is organized; there is no lost motion. There is complete coöperation between the staff, the men of science, and the manufacturers. … It is wonderful. A whole nation at war is an awe-inspiring sight.”

I.

As one approaches the great battle-line of Europe, the most impressive fact is the existence of order. Every man has his definite work to do; there is no hurry, no confusion. At every crossroads there is a director of traffic, for all the world like Piccadilly Circus; every motor-truck, every field-gun, has its appointed road to follow. Chance is excluded as a factor. The same idea controls the actual fighting—on the land, in the water, in the air; everything is regulated by knowledge, that is, by science. This does not mean military science in its narrow sense—far from it. It means that the general staffs realize the possibility of making use of scientific knowledge and the desirability of consulting scientific men.

Other features of the Front are striking: the magnitude of the preparations for battle, calling for the services of great business men; the attention paid to the social and physical well-being of the soldiers; and many other facts; but, the more one goes up and down the battle-line, the more one is amazed at the vital part which science is playing; and, the more closely one is allowed to enter into the councils of the staffs, the more apparent it is that men of science have a field of usefulness never before opened to them.

A clear-seeing, clear-thinking American chemist, who was in Germany and England for many months in the year 1916, having unique opportunities for observation in both countries, summed up the situation in a few words, which I heard him say soon after his return to this country. The substance of what he said was this: ‘There is not the least uncertainty as to how this war will end. At its beginning, the German General Staff summoned the scientists of Germany into consultation on every step; each branch of the army called to its service professors from the universities and scientific experts from tis numerous factories; but, as the war continued, the policy changed, the regular officers of the army replaced the scientific advisers, and now the latter have little influence. In England, the course of events has been the reverse: in the beginning the Staff officers had their way; but, as the months passed, more and more were the men of science called to help in advice and in actual field duty, until now every man of note in the scientific life of England is at work for the country. No fact is more striking in the history of the war; none will have consequences so far-reaching.

I will add to this, that in France the work of scientific laboratories has always received due and proper recognition and does now. This fact was realized more or less clearly in this country, and in the spring of 1916 the National Academy of Sciences, at the request of President Wilson, organized a National Research Council, composed of engineers, university professors, and government officials, to make a study of the relation of science to war, and to be prepared to help the government in all scientific matters. Immediately after this country declared war, this Council decided to send to Europe a commission of six, who should see with their own eyes what the part of science in the war was. It was my privilege to be one of these. We reached France toward the end of April, and returned to America early in July. We were welcomed by the French government, and later by the English, and were given every opportunity to ask questions and to observe. M. Painlevé, the Minister of War, at our first official reception, said to us, ‘Every door in France is open to you’; and so we found.

In what follows I shall confine myself largely to my personal impressions and experiences; and I am sure that all of my associates could tell stories even more interesting. I cannot speak with any clearness of the hospital and sanitation service, of the work of the different medical research committees, of the scientific work in connection with food, of the wonderful institutions for the reeducation of the maimed and blinded, although all these were studied by some of us; but even I, a physicist, was conscious of the evidence of the astounding progress made by the French and English doctors and scientists.

We were placed in contact at once, both in Paris and in London, with the men we wished to see, many of whom were, of course, friends of long standing. We were shown laboratories, manufactories, testing-grounds, and given every imaginable help to get answers to questions and to see undreamed-of investigations. It was a most wonderful experience, to see the mobilization of a nation. There was no one, be he artist, merchant, scientist, or workman, who was not giving his service to his country. Office-hours and work-hours were from seven o’clock on; they had a beginning, but I never saw their end. Each week had seven days; for France and England know that they are at war, and modern warfare does not respect Sundays or festivals.

All the scientific work of the country is organized; there is no lost motion. There is complete coöperation between the staff, the men of science, and the manufacturers. The officer in the Army or Navy states his problem: he wishes to be able to locate the position of a batter of guns or a submarine; the scientific advisers instantly set to work. A geologist thinks his science can be of use to the general at the front; he is at once given an opportunity of proving the correctness of his idea. An airplane pilot thinks he can improve his machine; a manufacturer without a day’s delay, makes the alteration desired. It is wonderful. A whole nation at war is an awe-inspiring sight.

In Paris, which is now the centre of France, as never before, we received our theoretical instruction. We were interested in knowing about maps, for instance. We called, by appointment, to see the chief officer; he received us and at once gave us a lecture, with the clarity and breadth of view of a master, on the administration under his charge, telling us of each stage in the process of acquiring knowledge of the enemy’s country and putting this on the printed map. We asked for more details, and all were explained. Then we were shown the actual working of the machinery; all the instruments, the organization of the personnel, the printing processes themselves.

Or, we wished to know about airplanes. We were shown the experimental laboratories and wind-tunnels, the manufactories, the new engines undergoing their various tests, the aviation fields, and finally, as an illustration of how air-planes were used, we were shown the system for the defense of Paris against raids through the air.

So it was with respect to every subject. Nowhere were we more impressed than in Paris by the fact that the French are a serious people. Each man is keen in his profession, earnest in his work, eager to talk about it to any one like himself, anxious to be of help in any way, and frank in describing defects or lack of perfection. The French army officer is the most wonderful man I met in Europe.

In England, too, our experiences were similar, only different in ways one expected, knowing the English people. In that country we visited individuals, rather than departments. The attitude of an Englishman toward his work is so different from that of a Frenchman; on the face of things, he is not proud of his achievements, he would rather show you a series of failures than the final success.

One incident among many will illustrate this. We wished to see the great aviation field at St. Omer; and, on our arrival, the officer in charge asked me what I would like to see. I said, among other things, air-plane instruments. His reply was, ‘Right-o. Come over here. In this shed I have all of our broken-down instruments. What do you think of a government which would send us such things?’ Finally, after due effort on my part, we were shown the instruments with which he was satisfied.

After we had been taken all over the field, we were about to leave, when I saw, a hundred feet away, what looked like a new type of air-plane; and I asked what it was. He was delighted to show it to me; it was the very latest machine. He told me what a surprise it had been for the Germans, and what a great success. It was the machine actually used by Captain Ball in running up his record of destroyed German machines to over forty. Now, this young officer simply could not have shown me that machine on his own initiative; he was so proud of it that he would have considered it a form of boasting, of ‘side’; but the minute I asked questions, he was free of all responsibility. One can easily see that this quality of an Englishman makes it necessary for the visitor to know beforehand what he wishes to see. The latter is helped, though, by the intense frankness of an Englishman after his confidence is once secured, and by his deep pleasure in the fact that his brethren, the American people, are at war by his side, and share his ideals.

After several weeks of preparation we were taken to the actual battle-front, and shown how, in real hourly conflict, the methods and apparatus of science are applied. In Paris and London we learned the theory; at the front we saw the practice. Each confirmed the other. I was for five days the guest of a French army, passing from Rheims to Verdun; and for five days at the British headquarters, being taken along the line from Arras nearly to Ypres. I can truly say that the excitement, the mental stimulus, of seeing what the various applications of science to war meant rendered me unconscious of everything else. Shells often fell near us, they were nearly always passing over us eastward; we would fall and stumble into and out of shell-holes; we were in the midst of the horrors of a recent battlefield; none of these things made any real impression. No one, who has not had a similar experience, can picture the way in which one’s senses are all deadened except those being used for the purpose in hand.

II.

It is difficult to make a beginning in telling of what I saw of the uses of science. It must not be thought that I can in one article, or even a dozen, tell the whole story. I think it safe to say that there is no branch of science which is not being applied in this war. This was a most surprising fact to me. Take geology. I had heard that geologists were attached to the Staff; but I had pictured them as mining engineers rather than as professors of the pure science. Imagine, then, my surprise when I found in one of the rooms at Headquarters a world-famous geologist studying and marking areas on a geological map of Flanders. All this country through which the battle-line passes has been studied with care by geologists for many decades, and Belgium and France have both published sets of maps showing all the geological details. On the professor’s table was a map of the district directly east of Ypres; he was coloring certain areas red and others various shades of blue. He was also marking certain points and drawing a few straight lines.

Naturally I asked what it all meant. One color meant, ‘Here it is safe to make dug-outs’; another, ‘Here you will strike rock’; another, ‘Look out for quicksands’; and so forth. The points meant, ‘Dig for water.’ I asked him why he did not use a divining-rod expert (only I said a ‘dowser,’ as I was speaking real English). He laughed and said that unofficially he might do so. The straight lines meant, ‘Here you may make tunnels or burrow mines.’

I saw on the walls of the room vertical sections of the country, and inquiry brought the answer that they were for the study of underground water-systems; for the rise and fall of such might interfere with tunnels and mines, and so knowledge of them is necessary. Never have I spent a more interesting hour. It was said that one reason for the great success of the British operations at the Messines Ridge, when fifty or more mines were exploded, was the skill of the geologist who planned their location; for in some cases they were so surrounded by quicksands that the Germans could not countermine. I cannot vouch for the truthfulness of this, but, personally, knowing the men concerned, I believe it.

In this war the ‘weather man,’ the meteorologist, has come into his own. No one laughs at him now. His information is desired by the artillery officer who has to know the temperature of the air and its moisture-content, the strength of the wind at different levels, and the like, in order that he may aim his guns. When the temperature is hovering about the freezing point, the Staff wish to know if the improvised roads will be frozen sufficiently to permit the movement of guns or motor-trucks. The captains of the air-squadrons must know the condition of the atmosphere up to heights of 20,000 feet. The importance of the information may be judged from the fact that we were asked repeatedly if there was not some way by which the American weather reports could be kept from reaching Germany. Our reply had to be that, with Mexico where it was, nothing could be done.

At the beginning of the war the value of meteorological predictions was not recognized by the Allies. Two incidents produced a sudden change. One morning the batteries were ordered to resume firing at the same range as on the previous afternoon; no change in elevation was made, and the shells began landing in their own front trenches, whereas the day before they had reached the enemy’s lines. Such is the effect of marked changes in the air. In the early days the British weather reports leaked into Germany; and one week every condition reported indicated that for a few days ahead the weather would be such as the Germans desired for the dispatch of Zeppelins over England. The forecasters in London, however, did not, in their printed statements, tell all that they knew, and informed the Admiralty that a change was probable which would make the conditions favorable for attack on the Zeppelins. The latter came, and found the British read for them. From that time on the meteorologist came into favor. Now there are observing stations at short intervals all the way from the Channel to the Alps; and information is sent out, in the form of bulletins, several times a day.

Ever since gunpowder was introduced into warfare, chemistry has been recognized as the one science which was essential in preparations for war; but a new chapter was opened when the Germans introduced poisonous gases as an instrument of death, in place of bullets. This was at the second battle of Ypres, in which the Canadian soldiers suffered so cruelly. The plan then followed was to transport to the front-line trenches steel cylinders containing the liquefied gases, level down the edge of the parapet toward the British forces, letting the nozzles project over the top, and then wait for a favorable wind.

Of course, as soon as the idea of the Germans in planning this hideous mode of warfare was recognized, it became comparatively easy to block it; the preparations could always be seen; then a bombardment could be set up which destroyed the tanks where they were, much to the distress of the Germans themselves. Consequently, the manner of using poisonous gases had to be altered; and the plan adopted was to take the shells in use with the big guns and fill them with the liquefied gases instead of with shrapnel. Special guns were devised for use at short range; and these so-called gas-shells now form a most important feature of artillery.

The only protection against these gases is a mask which may be put on quickly, and which is so constructed mechanically that the man can breathe in and out without strangling. The part of the chemist was to determine what substance should be put in the passages through which the air is inhaled, so as to absorb the poisonous gases. The way in which the French and English chemists solved this problem—for it is solved—excites the admiration of the world; and the real scientific work done in connection with it is a great contribution to pure science.

When the moral question involved in this use of gas as a weapon in war was settled and the Allies determined also to adopt it, chemists were again appealed to. The result has been a study of hundreds upon hundreds of gases, their toxicity, their density, their liquefaction, and the ease of manufacture; and here again the purely scientific side of the subject will be of permanent value. The work is going on unceasingly. Chemists are attached to all the armies, and chemical laboratories are in operation; so that, if the Germans send over any new shells, — and a certain proportion always fail to explode, — they may be investigated instantly. If the British line receives this favor from the Germans, the gas is studied, and the French chemists are told; and vice versa. There is complete coöperation. All the time, too, great laboratories in Paris and all over England are at work; all the chemists of both countries are government servants to-day. The men employed in actual scientific work, including testing, are numbered by tens of thousands.

Among the other ways in which chemists are helping to win the war is one which will probably strike an American as semi-amusing, although it is far from it. This is by the investigation of invisible inks. The subject sounds reminiscent of detective stories. As a matter of cold fact, England and France are thoroughly penetrated by the German spy system; and the Secret Service officials of both countries are kept busy to the utmost of their ability in order to cope with the situation. It is much easier to devise an invisible ink that it is to discover the method by which the writing may be revealed. For, imagine a piece of apparently blank paper being found under suspicious circumstances: what should one do with it? Expose it to some gas or liquid which might bring out the written words? How can one be sure that the gas or liquid thus used may not obliterate the traces sought? This is the exact difficulty. Many inks are in use, of such a character that the obvious tests would result in a destruction of the evidence. The moral is, do not use the obvious tests. One can easily see what a field there is here for chemical investigation; and it is satisfactory to know that they have been made, and are continuing.

Other ways in which chemistry is being applied in warfare are numerous, indeed, abut are almost obvious to one who asks himself how it could be used. The all-important fact is that the professional soldier has come to recognize the value of the chemist, and the latter has welcomed the opportunity for service.

Whether or not camouflage is a part of science, I cannot decide. What is certain is that the French government included it as a part of our programme of investigation of the scientific work of France. The word itself, I was told, was adopted form the stage, meaning the art of making something look different from what it really is—hiding reality in the guise of innocence. This art is surely a science now, in its perfection. I was walking—struggling rather—up the hill on whose summit is the tiny abri known as the Fort of Douaumont, when I heard a battery of French ‘seventy-five’s’ operating very near; the shells were flying within a few feet of me. I looked around to see where the guns were, and I could not discover anything. The hill-side, as far as I could see, was simply a desolate waste of pock-marked earth, one shell-hole after another. Finally I saw wisps of faint smoke, that was all. My companion smiled, and asked if I couldn’t’ see the guns. I said I could not, and he replied that he was glad, because then no enemy could either. As I was then shown, the battery was about one hundred feet away. Such is camouflage.

We saw the whole process at another time. Great nets are suspended in a shed, and bunches of dried grass, stained to suit definite conditions, are tied on; when the net is spread over the ground and elevated slightly where necessary, forming inconspicuous humps over the batteries. If the neighboring earth is reddish, so are the bunches of grass tied to the nets. When two front-line trenches face each other for some time, the observers on each side get to know each minute feature of the territory between. Then some day a photographer and an artist come to the front trench, and note with scrupulous care some object, a branchless tree, a dead horse, even a dead soldier; within a few hours an exact copy is made, having a steel framework sufficient to conceal a man; in the night the real tree or horse or man is removed, and the steel image is substituted, with is observer of listener inside. Stories are told of the two enemies trying to replace the same object at the same time, with fatal consequences to one. Other illustrations of camouflage were shown us, but I hesitate to describe them, because I am convinced that the Germans do not as yet know them all. When it comes to a combination of imagination, artistic ability, and scientific ingenuity the French people cannot be equaled.

We felt sure when we reached France that there was at least one branch of science in which there would be but few surprises for us, if any That was map-making. But pride met its usual fate. We saw things of which we had never dreamed, largely, I must say, because we had never visualized this war. Parenthetically I may add that no one can who has not been in the midst of it. The French had enormous difficulties in the first months of the war. This must sound surprising to any one familiar with the wonderful maps of France which we all used when motoring or walking there in the years before the war. But war-maps must be drawn on a huge scale, showing minute details; so that existing maps must be magnified greatly; further, the accuracy required is the utmost limit attainable in the science of topography.

The Germans in their rapid sweep over northeastern and eastern France destroyed the marks of reference used on the existing maps! Consequently new surveys were necessary along the line of contact of the armies; old survey records of fields and villages on record in the district offices, corresponding to our county court-houses, were hurriedly obtained, and in a moment the new maps were ready; only the fine details had to be added gradually. But this was only the beginning; for the fighting up to now has been trench-warfare; and the progress of a battle-line forward or back is measured by feet. So that a map must show, not simply roads, churches, and bridges, but the enemy batteries, the service railroads, the trenches, shelters, food-depots, and all the rest.

Further, different types of maps are required for different services: the Staff must have one kind, the artillery officer another, the trench-commander another, and so on, almost without limit. The complication and difficulty are increased by the fact that the details supposed to be revealed by a map are changing every day: new rails are laid, new trenches are dug, the positions of new batteries are discovered. As a consequence, new maps for large stretches of the front are necessary every day of the year! The facts discovered to-day must be on the maps in the hands of the officers to-morrow; and it is done. It is easier to imagine the organization than to describe it; but the demands upon the engineering forces of the armies call for and receive the utmost skill and scientific training.

In this rôle of aiding in making maps, air-planes are essential. Information is desired as to the enemy’s country over a certain sector; up goes flight after flight of air-planes, a thousand photographs are taken, the plates are developed within a few minutes, trained observers with microscopic care compare these with the existing maps, new features and alterations are noted, and corresponding changes are made on the maps. Then reports are received from the observation-posts and the gun-locating stations, and their information is recorded; within a few hours everything is ready for the lithographing; and in twelve hours the officers at the front have their maps. The great variety of maps furnished and the rapidity of their preparation are entirely novel features of this war.

Another science which has come to the front of the stage is metallurgy. Of course, this was expected, and both France and England were prepared, in the sense that they had the men and the methods. But many novel problems have arisen and have been solved. Chief of these were the substitution of some metal for ordinary steel, and the preparation of alloys having a light weight. Fortunately, it has been the practice in all countries to employ in connection with the great steel works, groups of scientific men, chemists and physicists; and the realization of their importance is no new feature of the war.

III.

Physics is a science which covers many subjects. Of these, acoustics is one to which in recent years less and less attention has been paid, owing to the apparent growth in importance of other subjects, notably electricity and temperature measurement. In fact, I know several institutions—one is the greatest school in England—where acoustics has been omitted altogether from the one-year course in Physics. And now, to a physicist, the most striking feature of this war, so far as science is concerned, is the wide use of the phenomena concerned with sound. Yet, when one stops to think, there is nothing in this to cause surprise. One of the needs of a combatant is to detect the presence and position of one’s enemy: air-planes are very noisy; when a gun expels a shell there is a sound; and submarine engines cannot be made noiseless. Again, sound-waves may be emitted from any such source as a horn or a whistle, and may be used for signals on a dot-and-dash system, or use may be made of their echoes.

Here was a wide field at once for physicists; and both in France and in England we saw the results of their work. Perhaps the most interesting of these was the method of locating the position of a gun of large caliber. When a shot is fired from a German gun toward the Allies’ line, the observer in the latter hears three sounds. The first of these is the sound due to the passage of the shell through the air—this is because the velocity of the shell is greater than that of sound-waves; the second sound to be heard is the boom of the gun itself; and the third is that due to the explosion of the shell. So, if there are two or more ‘receiving stations,’ at each of which some such apparatus as a simple microphone is installed, and if each of these is connected by wires to a central station where there is a recording device, each microphone will register the arrival of the three sound-waves; but, since the receiving stations are at different distances from the gun, any one type of waves, for instance, the ‘boom,’ will reach them at different instants of time. In order to know the time-intervals, all that is necessary is to make an extremely accurate clock record its indications on the same strip of paper that receives the microphone signals. Then knowing the velocity of sound-waves, as we do, and also the exact situation of the receiving stations and their relative distances, it is a simple matter to work out graphically the position of the gun.

The only uncertain element in the process is the velocity of the sound-waves, because it varies with the temperature of the air—fortunately in a known matter; and it is affected by the wind, fi this is strong. But corrections can be made, and the accuracy obtained is truly surprising. One way of verifying the result is to send up an air-plane and photograph the region. When this is done, it is found that the two methods agree so closely that, if on the largest scale maps a gun’s position as determined by one is marked by a pin, the position as found by the other cannot be marked by a second pin—there is not space. This means roughly that the location of a gun at a distance of six miles can be determined definitely within some fifty feet, which is sufficiently close. The English officer who had charge of the sound observations at the Messines fight told me that in one day sixty-three large German guns were located, and all sixty-three were destroyed. Naturally, the receiving stations have to be close to the front line, and the central station cannot be far back. One day I visited such a station in a French town. It had been under bombardment only a few hours before; the house next to the one in which I was making my visitor’s observations was still smoking; and the men in charge of the apparatus were just working out the position of the gun which had been worrying them.

Another way in which the situation of a gun is revealed is by the flash it emits, which of course can be seen for a long distance at night, if the observing post is sufficiently high above the ground. All that are required for this purpose are several such posts, and a knowledge of their positions; then simple triangulation methods give the desired result. The only trouble arises from possible uncertainty as to whether all the observers are looking at the same flash: but due care is taken of this.

Wireless telegraphy is used in numerous ways: for signaling from airplanes, and for sending messages for small or great distances. Listening apparatus, involving telephonic principles, is installed in the very front-line trench. One day I was taken to see such an apparatus in the French lines running across the Argonne Forest. It was a beautiful day: the air was full of the fragrance of apple-blossoms, the scenery was lovely and peaceful. We turned off the main road, and our speed doubled. I asked why, and my staff-officer said, ‘This road is in full view of the Germans, and if they see civilians they may take a shot at you.’ Soon we were over this bit of road, and after passing one or two burned châteaux and what had been a lovely town, with its hall, its church, and every house a mass of ruins, we reached the actual front line, or at least a point as close as a motor could approach, even in the shelter of a deep ravine. On climbing up to the listening post, I was interested to see recorded, upon the last page of notes of the soldier in charge, this whisper from the German lines (not in English, naturally): ‘There is a staff automobile on —— road, with apparently some civilians in it.’ Perhaps a second look told the Germans we were not worth shooting at; anyway we had no ‘events,’ coming or going.

Physics includes in its scope the phenomena of light; and one of the important questions our commission had to ask in Europe was what progress had been made in getting optical glass, because before the war this had been nearly a complete monopoly of Germany’s. We found that the French and English both were getting good glass, though not in large quantities; and what was even more satisfactory was to see the development in optical instruments, especially lenses for photography and telescopes for the use of the artillery. I am absolutely sure that I have never seen as good lenses as those now made in Paris; when tested in any way, their results are unequaled.

While speaking of glass another fact may be of interest. Clinical thermometers have, in the past, been a feature of Germany’s trade; and so, when the German prisoners in France were being sorted out last year, they were asked if any of them were thermometer-makers, and if so, would they care to work at their trade. A large number stepped out; and now nearly all the thermometers for use in France are made by these German prisoners. Their workshop is in one of the old dismantled forts near Paris, and apparently they are most happy in their work. Possibly this is in part due to the fact that they are teaching their art to a number of French women.

No one can think of this war without having somewhere in the picture an air-plane and a submarine. The problem, at least, it was when I was in France in June; but it is pleasant to record the fact that the latest word I have received from Europe—from a keen American physicist—is, ‘I think they have at last got it.’ This is not the place to describe the attempts made by the physicists of France, England, and America to devise a method to determine the approach of a submarine; but it is worth noting that the very best men in all three countries are at work, new physical methods of great scientific importance at least have been developed; and whether or not the solution of the submarine question is more, and ever more, destroyers, pure science has gained enormously. We now have new methods and new apparatus of great power.

As to air-planes, where can one begin, and having begun, how can one stop? The time has gone by when the village blacksmith can make one, and when the inventor, who is tired of trying to persuade a banker to become interested in perpetual motion, turns his hand to an air-plane ‘on an entirely new principle.’ The air-plane of to-day is the very last word of the physicist, the engineer, and the manufacturer. The physicist has designed the planes of the machine and the shape of the body; the engineer has used the utmost of his skill in calculating the structural strength of its parts, and in furnishing an engine of unheard-of power in proportion to its weight; the manufacturer uses the same refinements in his work that he would in making a piano for an exhibition. The finished product is a real work of art. The workmanship to-day is nearly perfect. A great French manufacturer, whose factory turns out its thousands of machines each month, told me with pride that since the beginning of the war not one of his machines had broken in the air. And the engines. No one who is not an expert, and I am not, can appreciate the progress made within three years; progress in lightness, in power, in durability.

I am often asked which country has the best air-plane. Such a question has no meaning except ‘as of —— date’; because the machines are perfected every week, every month; further, the purposes has to be specified. Air-planes are used in the war for so many purposes—bomb-dropping, photography, spotting the fire of big guns, attacking land forces, and protecting other machines. There are machines made to carry a dozen men, or their equivalent weight in bombs; there are ‘two-seater’ machines for observation purposes of various kinds; there are the scouts of fighting planes. These last are the most beautiful, the most graceful machines one can imagine. Their speed is at least 135 miles per hour, and their ease of control is such that, if a pilot simply thinks of turning to the left or right or up or down, the machine does it. If a bird were to be conscious of knowing what a modern pilot does daily, hourly, with his air-plane, it would look upon him the way we look upon a bird. The use of air-planes in taking photographs has been referred to; and every one is familiar with the results.

The spectacle of a combat between two air-planes is, I suppose, the most thrilling spectacle man can witness. It is a tournament of the Middle Ages, with the course in three dimensions instead of one, and with a space of thousands of feet in which to manœuvre. Almost as thrilling to me was the sight of an air-plane spotting the fire of big guns: the monster 13-inch guns, the swift air-plane, the firing of the guns in order, by directions from the air, the speedy reaching of the target, and the consequent destruction of the enemy battery twelve miles away! Science was used every second: signals to the air-planes, wireless messages back, and the aiming of the guns with all the accuracy of geodesy.

I cannot resist the temptation to add a statement which has no connection with my subject, but which should be of interest. When I was in France in June, the Allies had a definite superiority in the air, better air-planes of all types, and more pilots of the highest quality. In ten days at the Front, I did not see one German air-plane in the Allies’ territory, and each hour the French and English machines were sailing where they wished.

Almost as beautiful a sight as an airplane is a modern captive balloon of the oblong type floating majestically high above one. The impression of a battle-line with these aerial observation posts every ten miles or so, will always stay in one’s memory. Their design is due to the French, and a profound knowledge of wind-resistance is shown. As an accomplishment in mechanics, I saw nothing in the war so extraordinary as the apparatus for hauling down these huge creatures; it is a powerful winch, and it lowers the balloon at the rate of one thousand feet a minute.

These are only a few of the ways in which science is helping the Allies to win the war; for it was evident to a lay observer like myself that in all these applications of science the Allies have a marked superiority. I have not said anything in regard to engineering as such. To me it is impossible to draw any line between this science and the so-called pure sciences. All applications of science are based directly upon experiments and investigations in scientific laboratories; and there is no discovery either of fact or of method which may not be used in connection with daily life. This is specially true of this abnormal life which we call war.