Clouds, say the text-books of meteorology, are collections of partly condensed water vapour or of fine ice crystals. Clouds, mentioned in terms of the newspaper and the club, are dingy masses of nebulousness under which the dubious politician, company promoter, or other merchant of hot air is hidden from open attack and exposure. Clouds, to the flying officer on active service, are either useful friends or unstrafeable enemies. The hostile clouds are very high and of the ice-crystal variety. They form a light background, against which aeroplanes are boldly silhouetted, to the great advantage of anti-aircraft gunners. The friendly or water-vapour clouds are to be found several thousands of feet lower. If a pilot be above them they help him to dodge writs for trespass, which Archibald the bailiff seeks to hand him. When numerous enough to make attempts at observation ineffective, they perform an even greater service for him—that of arranging for a day's holiday. And at times the R.F.C. pilot, like the man with a murky past, is constrained to have clouds for a covering against attack; as you shall see if you will accompany me on the trip about to be described.

The period is the latter half of September, 1916, a time of great doings on the Somme front. After a few weeks of comparative inaction—if methodical consolidation and intense artillery preparation can be called inaction—the British are once more denting the Boche line. Flers, Martinpuich, Courcelette, and Eaucourt l'Abbaye have fallen within the past week, and the tanks have made their first ungainly bow before the curtain of war, with the superlatives of the war correspondent in close attendance. Leave from France has been cancelled indefinitely.

Our orders are to carry through all the reconnaissance work allotted to us, even though weather conditions place such duties near the border-line of possible accomplishment. That is why we now propose to leave the aerodrome, despite a great lake of cloud that only allows the sky to be seen through rare gaps, and a sixty-mile wind that will fight us on the outward journey. Under these circumstances we shall probably find no friendly craft east of the trenches, and, as a consequence, whatever Hun machines are in the air will be free to deal with our party. However, since six machines are detailed for the job, I console myself with the old tag about safety in numbers.

We rise to a height of 3000 feet, and rendezvous there. From the flight-commander's bus I look back to see how the formation is shaping, and discover that we number but five, one machine having failed to start by reason of a dud engine. We circle the aerodrome, waiting for a sixth bus, but nobody is sent to join us. The "Carry on" signal shows up from the ground, and we head eastward.

After climbing another fifteen hundred feet, we enter the clouds. It is now impossible to see more than a yard or two through the intangible wisps of grey-white vapour that seem to float around us, so that our formation loses its symmetry, and we become scattered. Arrived in the clear atmosphere above the clouds my pilot throttles down until the rear machines have appeared and re-formed. We then continue in the direction of the trenches, with deep blue infinity above and the unwieldy cloud-banks below. Familiar landmarks show up from time to time through holes in the white screen.

Against the violent wind, far stronger than we found it near the ground, we make laboured progress. Evidently, two of the formation are in difficulties, for they drop farther and farther behind. Soon one gives in and turns back, the pilot being unable to maintain pressure for his petrol supply. I shout the news through the speaking-tube, and hear, in reply from the flight-commander, a muffled comment, which might be "Well!" but it is more likely to be something else. Three minutes later the second bus in trouble turns tail. Its engine has been missing on one cylinder since the start, and is not in a fit state for a trip over enemy country. Again I call to the leader, and again hear a word ending in "ell." The two remaining machines close up, and we continue. Very suddenly one of them drops out, with a rocker-arm gone. Its nose goes down, and it glides into the clouds. Yet again I call the flight-commander's attention to our dwindling numbers, and this time I cannot mistake the single-syllabled reply. It is a full-throated "Hell!"

For my part I compare the party to the ten little nigger boys, and wonder when the only survivor, apart from our own machine, will leave. I look towards it anxiously. The wings on one side are much lighter than those on the other, and I therefore recognise it as the Tripehound's bus. There is ground for misgiving, for on several occasions during the past ten minutes it has seemed to fly in an erratic manner. The cause of this, as we find out on our return, is that for five minutes the Tripehound has been leaning over the side, with the joystick held between his knees while attempting to fasten a small door in the cowling round the engine, left open by a careless mechanic. It is important to shut the opening, as otherwise the wind may rush inside and tear off the cowling. Just as a short band of the trench line south of Arras can be seen through a gap, the Tripehound, having found that he cannot possibly reach far enough to close the protruding door, signals that he must go home.

I do not feel altogether sorry to see our last companion leave, as we have often been told not to cross the lines on a reconnaissance flight with less than three machines; and with the wind and the low clouds, which now form an opaque window, perforated here and there by small holes, a long observation journey over Bocheland by a single aeroplane does not seem worth while. But the flight-commander, remembering the recent order about completing a reconnaissance at all costs, thinks differently and decides to go on. To get our bearings he holds down the nose of the machine until we have descended beneath the clouds, and into full view of the open country.

We find ourselves a mile or two beyond Arras. As soon as the bus appears it is bracketed in front, behind, and on both sides by black shell-bursts. We swerve aside, but more shells quickly follow. The shooting is particularly good, for the Archie people have the exact range of the low clouds slightly above us. Three times we hear the hiss of flying fragments of high explosive, and the lower left plane is unevenly punctured. We lose height for a second to gather speed, and then, to my relief, the pilot zooms up to a cloud. Although the gunners can no longer see their target, they loose off a few more rounds and trust to luck that a stray shell may find us. These bursts are mostly far wide of the mark, although two of them make ugly black blotches against the whiteness of the vapour through which we are rising.

Once more we emerge into the open space between sky and cloud. The flight-commander takes the mouthpiece of his telephone tube and shouts to me that he intends completing the round above the clouds. To let me search for railway and other traffic he will descend into view of the ground at the most important points. He now sets a compass course for ToutprÈs, the first large town of the reconnaissance, while I search all around for possible enemies. At present the sky is clear, but at any minute enemy police craft may appear from the unbroken blue or rise through the clouds.

The slowness of our ground speed, due to the fierce wind, allows me plenty of time to admire the strangely beautiful surroundings. Above is the inverted bowl of blue, bright for the most part, but duller towards the horizon-rim. The sun pours down a vivid light, which spreads quicksilver iridescence over the cloud-tops. Below is the cloud-scape, fantastic and far-stretching. The shadow of our machine is surrounded by a halo of sunshine as it darts along the irregular white surface. The clouds dip, climb, twist, and flatten into every conceivable shape. Thrown together as they never could be on solid earth are outlines of the wildest and tamest features of a world unspoiled by battlefield, brick towns, ruins, or other ulcers on the face of nature. Jagged mountains, forests, dainty hills, waterfalls, heavy seas, plateaux, precipices, quiet lakes, rolling plains, caverns, chasms, and dead deserts merge into one another, all in a uniform white, as though wrapped in cotton wool and laid out for inspection in haphazard continuity. And yet, for all its mad irregularity, the cloud-scape from above is perfectly harmonious and never tiring. One wants to land on the clean surface and explore the jungled continent. Sometimes, when passing a high projection, the impulse comes to lean over and grab a handful of the fleecy covering.

After being shut off from the ground for a quarter of an hour, we are able to look down through a large chasm. Two parallel canals cut across it, and these we take to be part of the canal junction below ToutprÈs. This agrees with our estimate of speed, wind, and time, according to which we should be near the town. The pilot takes the machine through the clouds, and we descend a few hundred feet below them.

To disconcert Archie we travel in zigzags, while I search for items of interest. A train is moving south, and another is entering ToutprÈs from the east. A few barges are dotted among the various canals. Bordering a wood to the west is an aerodrome. About a dozen aeroplanes are in line on the ground, but the air above it is empty of Boche craft.

Evidently the Huns below had not expected a visit from hostile machines on such a day, for Archie allows several minutes to pass before introducing himself. A black puff then appears on our level some distance ahead. We change direction, but the gunners find our new position and send bursts all round the bus. The single wouff of the first shot has become a jerky chorus that swells or dwindles according to the number of shells and their nearness.

I signal to the flight-commander that I have finished with ToutprÈs, whereupon we climb into the clouds and comparative safety. We rise above the white intangibility and steer north-east, in the direction of Passementerie. I continue to look for possible aggressors. The necessity for a careful look-out is shown when a group of black specks appears away to the south, some fifteen hundred feet above us. In this area and under to-day's weather conditions, the odds are a hundred to one that they will prove to be Boches.

We lose height until our bus is on the fringe of the clouds and ready to escape out of sight. Apparently the newcomers do not spot us in the first place, for they are flying transverse to our line of flight. A few minutes later they make the discovery, turn in our direction, and begin a concerted dive. All this while I have kept my field-glasses trained on them, and as one machine turns I can see the Maltese crosses painted on the wings. The question of the strangers' nationality being answered, we slip into a cloud to avoid attack.

The flight-commander thinks it advisable to remain hidden by keeping inside the clouds. He must therefore steer entirely by compass, without sun or landmark to guide him. As we leave the clear air a left movement of the rudder, without corresponding bank, swings the machine to the north, so that its nose points away from the desired course. The pilot puts on a fraction of right rudder to counteract the deviation. We veer eastward, but rather too much, if the swaying needle of the compass is to be believed. A little left rudder again puts the needle into an anti-clockwise motion. With his attention concentrated on our direction, the pilot, impatient at waiting for the needle to become steady, unconsciously kicks the rudder-controls, first to one side, then to the other. The needle begins to swing around, and the compass is thus rendered useless for the time being. For the next minute or two, until it is safe to leave the clouds, the pilot must now keep the machine straight by instinct, and trust to his sense of direction.

A similar mishap often happens when flying through cloud. Pilots have been known to declare that all compasses are liable to swing of their own accord when in clouds, though the real explanation is probably that they themselves have disturbed the needle unduly by a continuous pressure on each side of the rudder-bar in turn, thus causing an oscillation of the rudder and a consequent zigzagged line of flight. The trouble is more serious than it would seem to the layman, as when the compass is out of action, and no other guides are available, one tends to drift round in a large circle, like a man lost in the jungle. Should the craft be driven by a rotary engine, the torque, or outward wash from the propeller, may make a machine edge more and more to the left, unless the pilot is careful to allow for this tendency.

Such a drift to the left has taken us well to the north of a straight line between ToutprÈs and Passementerie, as we discover on leaving the clouds for a second or two, so as to correct the error with the aid of landmarks. But the compass has again settled down to good behaviour, and we are able to get a true course before we climb back to the sheltering whiteness.

A flight inside the clouds is far from pleasant. We are hemmed in by a drifting formlessness that looks like thin steam, but, unlike steam, imparts a sensation of coldness and clamminess. The eye cannot penetrate farther than about a yard beyond the wing tips. Nothing is to be seen but the aeroplane, nothing is to be heard but the droning hum of the engine, which seems louder than ever amid the isolation.

I am bored, cold, and uncomfortable. Time drags along lamely; five minutes masquerade as half an hour, and only by repeated glances at the watch do I convince myself that we cannot yet have reached the next objective. I study the map for no particular reason except that it is something to do. Then I decide that the Lewis gun ought to be fired as a test whether the working parts are still in good order. I hold the spade-grip, swing round the circular mounting until the gun points to the side, and loose five rounds into the unpleasant vapour. The flight-commander, startled at the sudden clatter, turns round. Finding that the fire was mine and not an enemy's, he shakes his fist as a protest against the sudden disturbance. Even this action is welcome, as being evidence of companionship.

When the pilot, judging that Passementerie should be below, takes the machine under the clouds, I feel an immense relief, even though the exit is certain to make us a target for Archie. We emerge slightly to the west of the town. There is little to be observed; the railways are bare of trains, and the station contains only an average number of trucks. Four black-crossed aeroplanes are flying over their aerodrome at a height of some two thousand feet. Three of them begin to climb, perhaps in an attempt to intercept us. However, our bus has plenty of time to disappear, and this we do quickly—so quickly that the A.-A. batteries have only worried us to the extent of half a dozen shells, all wide of the mark.

We rise right through the white screen into full view of the sun. Apparently the sky is clear of intruders, so we turn for three-quarters of a circle and head for PlusprÈs, the third point of call. The wind now being behind the machine in a diagonal direction, our speed in relation to the ground is twice the speed of the outward half of the journey. The sun is pleasantly warming, and I look towards it gratefully. A few small marks, which may or may not be sun-spots, flicker across its face. To get an easier view I draw my goggles, the smoke-tinted glasses of which allow me to look at the glare without blinking. In a few seconds I am able to recognise the spots as distant aeroplanes moving in our direction. Probably they are the formation that we encountered on the way to Passementerie. Their object in keeping between us and the sun is to remain unobserved with the help of the blinding stream of light, which throws a haze around them. I call the pilot's attention to the scouts, and yet again we fade into the clouds. This time, with the sixty-mile wind as our friend, there is no need to remain hidden for long. Quite soon we shall have to descend to look at PlusprÈs, the most dangerous point on the round.

When we take another look at earth I find that the pilot has been exact in timing our arrival at the important Boche base—too exact, indeed, for we find ourselves directly over the centre of the town. Only somebody who has been Archied from PlusprÈs can realise what it means to fly right over the stronghold at four thousand feet. The advanced lines of communication that stretch westward to the Arras-PÉronne front all hinge on PlusprÈs, and for this reason it often shows activity of interest to the aeroplane observer and his masters. The Germans are therefore highly annoyed when British aircraft arrive on a tour of inspection. To voice their indignation they have concentrated many anti-aircraft guns around the town. What is worse, the Archie fire at PlusprÈs is more accurate than at any other point away from the actual front, as witness the close bracket formed by the sighting shots that greet our solitary bus.

From a hasty glance at the station and railway lines, while we slip away to another level, I gather that many trains and much rolling stock are to be bagged. The work will have to be done under serious difficulties in the shape of beastly black bursts and the repeated changes of direction necessary to dodge them. We bank sharply, side-slip, lose height, regain it, and perform other erratic evolutions likely to spoil the gunners' aim; but the area is so closely sprinkled by shells that, to whatever point the machine swerves, we always hear the menacing report of bursting H.E.

It is no easy matter to observe accurately while in my present condition of "wind up," created by the coughing of Archie. I lean over to count the stationary trucks in the sidings. "Wouff, wouff, wouff," interrupts Archie from a spot deafeningly near; and I withdraw into "the office," otherwise the observer's cockpit. Follows a short lull, during which I make another attempt to count the abnormal amount of rolling stock. "Wouff—Hs—sss!" shrieks another shell, as it throws a large H.E. splinter past our tail. Again I put my head in the office. I write down an approximate estimate of the number of trucks, and no longer attempt to sort them out, so many to a potential train. A hunt over the railway system reveals no fewer than twelve trains. These I pencil-point on my map, as far as I am able to locate them.

A massed collection of vehicles remain stationary in what must be either a large square or the market-place. I attempt to count them, but am stopped by a report louder than any of the preceding ones. Next instant I find myself pressed tightly against the seat. The whole of the machine is lifted about a hundred feet by the compression from a shell that has exploded a few yards beneath our undercarriage. I begin to wonder whether all our troubles have been swept away by a direct hit; but an examination of the machine shows no damage beyond a couple of rents in the fabric of the fuselage. That finishes my observation work for the moment. Not with a court-martial as the only alternative could I carry on the job until we have left Archie's inferno of frightfulness. The flight-commander is of the same mind, and we nose into the clouds, pursued to the last by the insistent smoke-puffs.

When the bus is once again flying between sky and cloud, we begin to feel more at home. No other craft come within range of vision, so that without interruption we reach Aucoin, the fourth railway junction to be spied upon. The rolling stock there is scarcely enough for two train-loads, and no active trains can be spotted. We hover above the town for a minute, and then leave for Boislens.

The machine now points westward and homeward, and thus has the full benefit of the wind, which accelerates our ground speed to about a hundred and fifty miles an hour. The gods take it into their heads to be kind, for we are not obliged to descend through the clouds over Boislens, as the region can be seen plainly through a gap large enough to let me count the R.S. and note that a train, with steam up, stands in the station.

As Boislens is the last town mentioned by the H.Q. people who mapped out the reconnaissance, the job is all but completed. Yet twelve miles still separate us from the nearest bend of the trench line, and a twelve-mile area contains plenty of room for a fight. Since the open atmosphere shows no warning of an attack, I look closely toward the sun—for a fast scout will often try to surprise a two-seater by approaching between its quarry and the sun.

At first I am conscious of nothing but a strong glare; but when my goggled eyes become accustomed to the brightness, I see, or imagine I see, an indistinct oblong object surrounded by haze. I turn away for a second to avoid the oppressive light. On seeking the sun again I find the faint oblong more pronounced. For one instant it deviates from the straight line between our bus and the sun, and I then recognise it as an aeroplane. I also discover that a second machine is hovering two thousand feet above the first.The chief hobby of the flight-commander is to seek a scrap. Immediately I make known to him the presence of hostile craft he tests his gun in readiness for a fight. Knowing by experience that if he starts manoeuvring round a Hun he will not break away while there is the slightest chance of a victory, I remind him, by means of a note-book leaf, that since our job is a reconnaissance, the R.F.C. law is to return quickly with our more or less valuable information, and to abstain from such luxuries as unnecessary fights, unless a chance can be seized over British ground. Although he does not seem too pleased at the reminder he puts down the nose of the machine, so as to cross the lines in the shortest possible time.

The first Hun scout continues the dive to within three hundred yards, at which range I fire a few short bursts, by way of an announcement to the Boche that we are ready for him and protected from the rear. He flattens out and sits behind our tail at a respectful distance, until the second scout has joined him. The two separate and prepare to swoop down one from each side.But we are now passing the trenches, and just as one of our attackers begins to dive, a formation of de Havilands (British pusher scouts) arrives to investigate. The second Boche plants himself between us and the newcomers, while his companion continues to near until he is a hundred and fifty yards from us. At this range I rattle through the rest of the ammunition drum, and the Hun swerves aside. We now recognise the machine as an Albatross scout or "German spad," a most successful type that only entered the lists a fortnight beforehand. Finding that they have to reckon with five de Havilands, the two Huns turn sharply and race eastward, their superior speed saving them from pursuit.

We pass through the clouds for the last time on the trip, and fly home very soberly, while I piece together my hurried notes. The Squadron Commander meets us in the aerodrome with congratulations and a desire for information.

"Seen anything?" he asks.

"Fourteen trains and some M.T.," I reply."And a few thousand clouds," adds the flight-commander.

By the time I have returned from the delivery of my report at G.H.Q., the wing office has sent orders that we are to receive a mild censure for carrying out a reconnaissance with only one machine. The Squadron Commander grins as he delivers the reproof, so that we do not feel altogether crushed.

"Don't do it again," he concludes.

As we have not the least desire to do it again, the order is likely to be obeyed.