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 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 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 of the detection of the latter is still a 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 purpose has to be specified. Air-planes are used in this 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 or 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

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 me

1

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.

I

I HAVE had many strange meetings - strange in place and attendant circumstance in various and sundry odd corners of the world, but, everything considered, I am inclined to think my encounter with Radovitch, toward the end of last March, was of them all the strangest.

It was on the gorgeously flower-carpeted slope of a mountain-side in- but let that transpire in its proper place.

There had been hints of gathering activity in the marching troops on the roads, and I knew that some kind of a skirmish was on, from the scattering spatter of rifle-fire above and to my right; but that I had actually blundered in between the combatants was not evident until the staccato of a suddenly unmasked machine-gun broke out in the copse below. I did not hear the familiarly ingratiating swish of speeding bullets, and merely an occasional twitching in the oak-scrub told of a skirmish

ing soldier. But it was plain that, if the rifles were firing in the direction of the machine-gun, and the machine-gun was firing in the direction of the rifles, my shivering anatomy came pretty near to blocking a portion of the restricted little neck of atmosphere along which the interchanged pellets must make their way. One never learns it until he is under fire-especially rifle-fire-for the first time, but the faculty for taking cover is one of the few things in which the more or less degenerate human of the present day suffers least in comparison with that fine and self-sufficient animal, his primitive ancestor.

I hurdled neatly over a natural 'entanglement' of magenta-blossomed cactus, dove through a bosky tunnel in the gnarled oak-scrub, and landed comfortably in the matted mass of soft maiden-hair, where the water dripped from the side of a deep hole excavated by the village brickmakers in taking out clay. There was ample cover from anything but high-angle artillery-fire on either side; so, picking out a bed of lush grass with a cornflower and buttercup pillow, I stretched in luxurious ease to let the battle blow over.

The rifles spat back at the woodpecker drum of the machine-gun for a minute or two; then suddenly fell quiet and gave way to the crashing of underbrush and the chesty 'tween-the-teeth oaths that tell of charging men. Scatteringly, in ones and twos and threes, they began stumbling by above my head, now revealed by the quick silhouette of a set jaw and forward-flung shoulders and now by the glint of a bobbing bayonet, but mostly by those guttural swear-words which mark the earnest man on business bent. One of them, a gaunt-eyed Serb in the faded horizon-blue uniform of a French poilu, — who passed near enough to the rim of my refuge to allow of a threequarters-length glimpse of him, carried

a squawking golden-hued hen by the feathers of her hackle; and I was just reflecting how every other soldier that I had ever known would have put a period on that tell-tale racket by extending his grip around the wind-pipe, when Radovitch came down to join me. Not that he had anything of the ulterior intention of seeking cover which brought me there — quite the contrary, indeed. I saw him, running hard and low (as every good soldier goes in to grip with his foe), burst out of the thicket, saw him straighten up and try to swerve to the right as the hole suddenly yawned across his path, and, finally, saw the quick tautening of the scaly yellow loop of earth-running aloeroot which deftly caught the toe of his shambling boot and defeated the

manœuvre.

There was little of the fine finesse of my own soft landing in the whacking kerplump which completed the highdive executed by Radovitch after his contact with the aloe-root. His gun out-dove him and cut short its parabola with the bayonet spiking a fernfrond on the opposite bank; but his broad, bronzed Slavic face was the first part of Radovitch himself to reach the bottom, so that all the inertia of the bone and muscle in his firmly knit frame was exerted in driving the ivory crescent of the teeth of his back-bent lower jaw in a swift, rough gouge through the yielding turf.

He pulled himself together in a dazed sort of way, sat up, rubbed the grass out of his eyes, and kneaded gently the strained joints of his jaw to see that they were still swinging on their hinges. Reassured, he spat forth sputteringly asphodel and anemone and the rest of his mouthful of gouged flowerbed, completing the operation by running an index finger around between the lower teeth and lip, to remove lurking bits of earth and gravel.

There was something strangely familiar in that index-finger operation, and it was the sudden recollection that that was the identical way in which we used to get rid of the gridiron clods that had been forced under our football noseguards, which was reponsible for my fervent ejaculation of surprise. I don't recall exactly what I said, but it was probably something akin to 'I'll be blowed!'

The look of dazed resentment on Radovitch's grass-and-dirt-stained face changed instantly to one of blank surprise, the poor strained jaw relaxed, and he turned on me a stare of openeyed wonder.

'Where in 'ell 'd you come from?' he gasped finally; and then, 'You speak English?'

When, ignoring the former query, I grinned acquiescence to the latter, he came back with, 'Ain't 'Merican, are you? Don't know New York, do you?'

On my admission of guilt on both charges, he crawled over and gripped my hand crushingly in his grimy paw.

'My name's Radovitch. 'Merican citizen myself,' he said proudly. "Took out my last papers just 'fore I came over to fight for Serbia. Went to school five years in New York when I was a kid. Ever been in Chicago?'

'Of course.' 'Omaha?' 'Yes.'

'I worked in the stockyards in both burgs. Made good money, too. Never been in Jerome, Arizona, have you?'

'Hit a drill all of a college vacation in the United Verde,' I replied, with a touch of pride on my own part.

'I dumped slag in the smelter at twofifty per,' said Radovitch. 'Hot little old camp, Jerome; but, say,'-with a climacteric pause, 'hain't ever been in Aldridge, Montana, have you? Coal town up near the Yellowstone - five

sixty-five fare from Butte. I got a store there, and a half interest in a dancehall and the baseball grounds.'

Aldridge- the Yellowstone-Butte those names conjured up thronging memories of a delectably renegade summer of semi-professional baseball that I had once played around among the mining-camps of Montana; and especially lurid were those that clustered about that little sport-mad 'coal town,' straggling up its rugged mountain valley almost under the golden portals of the National Park.

'You bet I have,' I replied, speaking deliberately and confidently as one who has much knowledge in reserve. 'Your dance-halls were as merry and bright as any I remember; but your ball-ground was also the rottenest. Did you own the half that took in the lake which occupied most of left field, or the half which included the cañon that sliced off the best part of right? I have to laugh yet when I think of the man with a boat you kept to paddle after the balls that went into the lake, and the bunch of kids scattered about the cañon to shivvy up the ones that went that way. It may interest you to know that I was first base on the Livingston team that gave Aldridge such a walloping on Miners' Union Day of —'

Bristling like a hedgehog, Radovitch reared up on both knees and shook his fists in my face as he roared excitedly, 'Livingston never did lick Aldridge. Seen all the games myself. Guess I know. Trimmed 'em ten to eight in

It was my turn to be indignant, but, keeping my temper with an effort, I only cut in icily with, 'I beg your pardon but since it was my own threebagger- and off your imported “pro.” pitcher from St. Paul at that into the sage-brush in deep centre that started the procession; and since I cleaned up twenty-five dollars, on the field sports (first in the broad-jump and