Things were really becoming very serious indeed, and I saw that something must be done at once to put an end to this disturbance. So, going over to M'Allister, I took him gently by the shoulders and pushed him out of the room, saying quietly, "Go to your own room at once; but for goodness' sake don't touch the machinery until the air has had time to put you right again. Leave me to deal with John." He rolled off through the doorway, still laughing "fit to split" as people say.
Returning to John, I tried to calm him down; but it proved a long and difficult task, though at last I succeeded in persuading him to go with me into our living-room and sit down quietly.
After sitting there some time, puffing away at his pipe, the fresher air began to have its effect; and soon I judged that he was calm enough to talk the matter over and discuss the situation more reasonably.
Then I said: "John, my dear fellow, please listen to me. You know we have now travelled quite 57,000,000 miles on our journey, and that all our arrangements have been made with a view to reaching Mars not later than the 24th of September, because it will then be at the point where it is in opposition to the sun as seen from the earth. It is merely a sentimental reason so far as the opposition is concerned, but there are substantial reasons for not delaying our arrival.
"You say we must go back, but please consider all that such a course must involve. Though the earth has been following us up pretty closely on a slightly different course it is at the present about 13,000,000 miles away from us. You will see it out there on our left hand towards the rear of the Areonal; but we cannot go direct across to where it is now, for by the time we reached that point the earth would have gone ahead several million miles. Our only course is to head it off, and, taking the shortest line, that means a journey of over 12,000,000 miles. Therefore, we cannot reach England until the 8th of September at the earliest, and as we shall require at least a week to lay in fresh stores, it will be the 15th before we can start again.
"Starting on the 15th September we should have to travel at least 54,000,000 miles before we could catch up Mars, and as that will take twenty-eight days, we could not arrive there before the 13th of October. (See the chart.) "Thus, we must sacrifice our chance of being upon Mars on the date of opposition, and also the opportunity of catching the first glimpse of our earth a few days later. If we continue our journey now and reach Mars on the 24th of September the earth will then be only 37,000,000 miles away; but by the 13th October it will be over 40,000,000 miles distant. There is the further objection that to get back again in reasonable time we must leave Mars by the 1st of December, and the loss of three weeks' time will deprive us of many opportunities of learning what there is to be found on the planet.
"Now, John, like a good fellow, just think over the matter quietly and reasonably; you will then realise that it is quite impossible to interrupt our journey and return to England as you suggest."
"I have thought it all out again and again," he replied, "and can only repeat, Professor, that it is quite impossible for me to go on minus my tobacco!"
"Was there ever such an obstinate and unreasonable man!" I thought to myself. "What can I do to put an end to this absurd difficulty?"
[Illustration: DIAGRAM showing the relative positions of the Earth and Mars at the various Oppositions of Mars, from 1892 to 1924.
Past Oppositions are shewn by the firm lines with the dates outside the Orbit of Mars. Coming Oppositions are indicated by the dotted lines with the dates inside the Orbit.
The distance between any two consecutive Oppositions represents the distance in excess of one complete revolution in its orbit passed over by the planet since the last preceding Opposition. These distances are greater on the left hand side because of the planet then being nearer the Sun and consequently travelling more rapidly.
Drawn by M. Wicks.
Resuming the conversation, and keeping as calm as I could in the circumstances, I placed the matter before him in all its aspects, and after we had been talking together for a long time, he seemed to be able to take a more reasonable view of the position. In order that something might be done to keep his mind from dwelling upon his proposal to return to England, I suggested that we should go to the store-room and thoroughly overhaul it.
He agreed to this, accompanying me to the store-room and pointing out the different places he had searched. The tins were in several sizes, but all were made square in order that not an inch of the available space might be wasted. We looked into a large number of tins which had not previously been examined, but without finding what we wanted.
At last a thought occurred to me, and I said: "You tell me, John, that you are quite certain you put up the tobacco and labelled the tin yourself, yet the tin so labelled was found to contain tapioca! Do you remember where the tapioca was stowed away?"
He pondered awhile, with his chin resting upon his fingers, then suddenly replied, "Yes, I think I know where it is," and, taking me over to another cupboard at the far end of the room, we made a further search and at last found the tapioca tin, opened it, and lo, there was the missing tobacco!
"Well, I'm blest!" said John, very slowly drawing out the words; then all his ill-humour suddenly vanished, and he burst into a most hearty laugh, in which I joined. Our laughter, indeed, was so mutually contagious, and so often renewed, that we had to sit down to finish it and recover ourselves.
Then John remarked, "Now, Professor, I think I can explain it all. You see I prepared and labelled those confounded tins before loading them up; so I suppose that when stowing away the parcels of tobacco I just glanced at the label on the tin and saw the letter T followed by the right number of other letters, and, taking it for granted that it was the tobacco tin, placed the tobacco in it. The only other tin left to pack was the one I supposed to be labelled 'Tapioca,' and no doubt, without troubling to look at the label at all, I put the tapioca into it; but, of course, it must really have been the tin labelled 'Tobacco.'"
Thus the matter was satisfactorily cleared up. John, having found his beloved weed and recovered from the effects of our patent Martian air, was now quite himself again, seeming very contrite, and apologising repeatedly for his rude conduct.
"That's enough, John," I said, as I laid my hand on his arm; "it is quite clear that what you did was mainly the result of the peculiar air you had been breathing, so I cannot blame you much. If I had not taken so many intervals in the purer air, I might perhaps have been equally affected; as it was, my temper was none of the sweetest."
M'Allister had also quite recovered by this time, and bore no ill-will towards John; indeed, I doubt whether he had any very clear recollection of what had occurred.
So that ended the matter; and this little explosion having cleared the air, we all settled down to our old amicable relationship. We, however, took the precaution of reducing the amount of nitrous-oxide gas in our mixture of air, with a view to preventing any similar untoward results in future.
A NARROW ESCAPE FROM DESTRUCTION--I GIVE SOME PARTICULARS ABOUT MARS AND MARTIAN DISCOVERY.
Things now went on quietly and, in fact, rather monotonously for several days; and then we met with another rather startling experience.
We were all sitting together in our living-room on the 9th of September, whiling away the time in a game of whist, and, as it was the final rubber and we were running very close together, we were quite absorbed in the play; although, of course, it was a dummy game.
Suddenly we heard a most tremendous crash, apparently from the right-hand side of the air-chamber, the vessel giving a violent lurch sideways, then shivering and trembling from end to end. The crash was immediately followed by a sharp rattling on the top and side of the Areonal, just as though a fusillade of good-sized bullets had been fired at us.
"My word! whatever's that?--one of the cylinders must have exploded," cried M'Allister, jumping up in alarm and running into the air-chamber. We followed him, and looked all round the room at the different machines and apparatus, but could find nothing wrong.
John, chancing to look up, however, at once noticed a large bulge on the inner shell of the vessel, high up on the right-hand side; and then, turning to me, pointed it out, saying, "I think, Professor, it is pretty clear now what has happened."
"Yes, that huge bulge explains itself," I replied; "undoubtedly a fair-sized meteoric stone has collided with our vessel. It is very fortunate that the stone was not much larger, or there would have been an end to the Areonal and to us as well. These meteorites travel at such tremendous speed that, on entering the earth's atmosphere, they become incandescent owing to the friction of the air, and, unless very large, are entirely consumed and dissipated into dust before they can reach the earth. Those that do fall are always partially fused on the outside by the tremendous heat generated by the friction of our atmosphere. These meteorites are what people call 'shooting stars,' and many are under the impression that they really are stars, until the difference is explained to them."
John said, "We ought to congratulate ourselves upon such a lucky escape from annihilation; for had our vessel been constructed of any metal less hard and tough than our 'martalium,' and without a double and packed shell, it must have been wrecked and entirely destroyed by the shock of the tremendous concussion it had sustained. Even the very metal of the casing might have been completely melted by the intense heat generated by the impact of the meteorite."
"Heh, mon!" exclaimed M'Allister; "it's all very well talking about our lucky escape, and putting it all down to your own cleverness in designing and constructing the Areonal; but you should rather give thanks to Providence for saving us, and for enabling you to take the precautions you did. I say, 'Thank God!'" he remarked, and he solemnly raised his right hand as he spoke.
"Quite right, M'Allister," replied John: "we are all too prone to credit ourselves with more than we are entitled to. At the same time, M'Allister, you must remember that we Englishmen recognise as fully as you do the over-ruling power of Providence, although we may not be quite so free in speaking about it in ordinary conversation."
"Yes," I added, "you may be quite sure, M'Allister, that we are equally as grateful as yourself for the mercy which has preserved us all from an awful death. My very first thought on realising our extremely narrow escape from destruction was to say 'Thank God!' but I did not say it aloud as you did. It is in matters like these that people differ according to their temperament and training; and it is not safe to judge another because, in any particular circumstances, he does not act in precisely the same way as we ourselves would."
Thus we travelled on and on, each day bringing us more than two million miles nearer to our destination. Mars was apparently increasing in diameter the nearer we drew to it, and the dark blue line around the south polar snow-cap, indicating the lake of water from the melting snow, was very conspicuous. The snow-cap had recently decreased rapidly, being now near its minimum and irregular in shape, for in the southern hemisphere it was now late in June. Pointing to the planet, I remarked, "There is our destination! We see it now as the poet pictured it for us, and the words of Dr. Oliver Wendell Holmes are very appropriate to the present circumstances: 'The snow that glittered on the disc of Mars Has melted, and the planet's fiery orb Rolls in the crimson summer of its year!'"
On the 18th of September we passed between the earth and Mars, nearly in a line with the sun. On that date Mars was in perigee, or at its nearest point to the earth during the present year. Its distance from the earth was then 36,100,000 miles, and it will not be so close again until the 24th of August 1924. We could not see the earth, as its dark side was turned towards us, and it was also lost in the brilliancy of the sun.
At this date we had travelled 88,000,000 miles since we left the earth, yet we knew it was there, level with our vessel, and only about 29,000,000 miles distant on our left hand, whilst Mars was only 7,000,000 miles from us on our right-hand side.
Our position now was as follows:--Taking an imaginary line drawn from the Areonal to Mars as the base line of an isosceles triangle, we were moving along the left side of the triangle, and Mars was moving in a slightly curved line along the right side. Our paths were therefore converging, and if all went well we should both meet at the apex of the triangle on the 24th September, as we had originally intended.
We therefore had six clear days to cover the distance of less than 12,000,000 miles, so we should have sufficient time to slacken speed at the end of the journey. (See the chart.) Mars was rapidly growing in size and brightness, for the distance between the planet and the Areonal was quickly diminishing as our paths converged, and the various markings on its almost full round disc formed the subject of continual observation and conversation. We had noticed on several occasions a mistiness on some parts of the planet, which I attributed to the vapours raised from the canals by the heated atmosphere.
On the 21st of September, when we were all enjoying a smoke in the "evening," and conversation had dragged somewhat, John started us off on a fresh tack and gave us something to talk about for a very long time.
He winked at M'Allister and, looking at me with a knowing smile, said: "Professor, as we are nearing our destination it might perhaps be well if you now gave us some detailed information respecting the planet, similar to that which you gave us when we were approaching the moon. It would be both interesting and useful; for we should learn much more from an orderly statement of the facts than we should from several long but desultory conversations."
"Yes, Professor," chimed in M'Allister, "I'm quite ready to learn something definite about Mars, for I can't say I really know much about it at present."
"Very well then," I replied, "it is upon your own heads, and if you are willing to listen to a rather long story, I am prepared to do the talking. Please remember, however, that it will require some time to make matters clear and understandable."
"Fire away, mon," cried M'Allister, "we will listen as long as you care to talk."
So I began--"Mars, as no doubt you are aware, is a much smaller planet than the earth, its diameter being only 4220 miles, which is a little less than twice the diameter of our moon.
"It would require nine and a half globes the size of Mars to make one globe the size of the earth; and even then it would not be so heavy, because the average density of Mars is only about three-fourths of that of the earth. Mars is the next planet outside the earth's orbit, so is the fourth from the sun. The orbit in which Mars moves in its journey round the sun is very much more eccentric than the earth's orbit; in fact it is more eccentric than the orbits of any of the larger planets. As a consequence, the planet's distance from the sun varies greatly according to the particular part of the orbit in which it may be moving. Its mean distance from the sun is 141,500,000 miles, its greatest distance over 154,000,000, and at its nearest approach to the sun, or 'perihelion,' as it is called, its distance is only 129,500,000 miles. Mars travels in its orbit at a mean rate of 15 miles a second.
"As its orbit is also eccentrically placed in relation to the earth's orbit, it follows that its nearest distance from us in any particular years may vary greatly. The nearest possible approach it can make in regard to the earth is a little under 35,000,000 miles; when at the opposite point of its orbit its nearest approach is about 62,000,000 miles from the earth. As the years of Mars and the earth differ greatly in length, and the two planets move at different speeds, the very favourable oppositions can only occur about once every forty-five years; though a comparatively near opposition occurs about every fifteen years. Such a close approach we have just witnessed, and it will be fifteen years before Mars is again so near to the earth!
[Illustration: CHART: showing the Orbits of the Earth and Mars, and the relative positions of the two Planets, during the years 1909-10. Mars passed over the dotted portion of its Orbit in the year 1910.
The Outer Circle is the Orbit of Mars, and the inner Circle is the Orbit of the Earth. The Seasonal points on both Orbits show the Seasons in the Northern hemisphere. In the Southern hemisphere the Seasons are reversed, "Summer" occurring at the point marked "Winter," and "Spring" at the point marked "Autumn," &c. &c.
The dotted downward line on the left-hand side shows the course taken by the "Areonal", which left the Earth on the 3rd of August and arrived at Mars on the 24th of September. * Shows the point reached when John wished to turn back; and the lower dotted line, the alternative course then suggested.
The long dotted line running upwards to the Spring Equinox of the Earth shows the course taken on the homeward Voyage.
Drawn by M. Wicks.
"The Martian year is equal to 687 of our days, but as the Martian days are slightly longer than ours, this really represents 668 Martian days.
"The entire surface of Mars contains an area of about 56,000,000 square miles, which is about one-fourth of the area of the earth's surface.
"Its gravity is only three-eighths of the earth's gravity, thus everything upon Mars would weigh proportionately lighter than on the earth, and the amount of labour required to do such work as digging or lifting would be lessened. There would, for the same reason, be greater ease of movement in walking, jumping, or running, and large bulky animals like our elephants could move with almost the same ease and freedom as our goats.
"Theoretically, we should expect to find the atmosphere upon Mars very much thinner than our atmosphere, and actual observation proves this to be the case. We are able to see details on the surface of Mars with very much greater distinctness than would be the case if its atmosphere were as dense as ours. Moreover, clouds are comparatively rarely seen; and the majority that are observed present more the appearance of clouds of sand than rain clouds. Usually, also, they float very much higher above the planet's surface than our clouds are above the earth's surface; ten miles high is quite an ordinary altitude, and some have been estimated as quite thirty miles above the planet.
"Many theorists have attempted to prove that, owing to the planet's distance from the sun, and the thinness of its atmosphere, the temperature of Mars must be very low, probably below freezing-point even at the equator. Dr. Alfred Russel Wallace has gone further than this, and suggests that the temperature must be eighty degrees Centigrade below freezing-point; that there is no water or water vapour on the planet; and that it is quite impossible for life to exist there!
"However, as the result of delicate bolometric experiments, careful calculations, and consideration of conditions affecting the result which have not previously received so much attention, Professor Very has arrived at a different opinion; and actual observation has shown that there is very little indication of frost outside the frigid zones. Even in the polar regions it is at times evidently warmer than at the earth's poles, because during the spring and summer the snow-caps upon Mars not only melt more rapidly, but melt to a much greater extent than our polar caps do. In 1894 the southern polar snow-cap of Mars was observed almost continuously during the melting period, and it was actually observed to dwindle and dwindle until it had entirely disappeared. It is rather strange to think that we know more about the snow-caps of that far-distant world than we do about those on our own earth.
"Owing to the lesser gravity on Mars the snow and ice which forms the caps would certainly be lighter and less closely compacted than the snow and ice upon our earth; but it is quite clear that it could not melt to any extent unless the temperature remained above freezing-point for a considerable length of time.
"It has, however, seriously been contended that the Martian polar caps are not snow at all, but frozen carbon dioxide--the poisonous dregs of what once was an atmosphere. Carbon dioxide, however, melts and becomes gaseous almost suddenly, but these polar snow-caps melt gradually, exactly as frozen snow would; so this theory fails altogether to fit the circumstances.
"Moreover, the water which accumulates all round the base of the melting snow-cap has been carefully observed on many occasions, and in the early stage of melting it appears blue in tint, but later on, as upper layers of snow dissolve and those nearer the soil are reached, the water presents a turbid and muddy appearance; exactly what might be expected when water has been contaminated by the surface soil.
"Dr. Alfred Russel Wallace declines to accept the blue tint as any proof that the liquid is water, and contends that shallow water would not appear that colour when viewed from a distance. You will, however, have observed that the water in all our shallow reservoirs appears intensely blue when observed from any distant and elevated point of view. It seems to me that when, as in the case of Mars, we have a very thin atmosphere laden with sand particles, we have exactly the conditions which would produce a very blue sky, and cause the water to appear a deep blue colour when viewed from a distance.
"It is also contended that water cannot be present on Mars, because none of our skilled spectroscopists has yet been able to demonstrate by the spectroscope that there is any water vapour in the Martian atmosphere.
"This, however, is generally acknowledged to be a very difficult and delicate operation; and, in any case, it is purely negative evidence, and cannot be accepted as final. I feel quite confident that sooner or later a means will be found of definitely proving the presence of water vapour upon Mars by the aid of the usual lines in the spectrum. There are too many evidences of its presence, such as clouds, hoarfrost, snow, and seasonal changes in vegetation, to warrant the rejection of the idea of its existence merely because it has not been detected by the particular means hitherto used by the spectroscopists.
"Mr. Slipher, of Flagstaff Observatory, has made many experiments with specially sensitised photographic plates. He has taken several photographs of the spectrum of the moon and others of the spectrum of the planet Mars. The plates of the lunar spectrum show a darkening of the 'a' band, which indicates the presence of water vapour, and we know that is due to the water vapour in our own atmosphere. The plates of the spectrum of Mars show a much more definite darkening of the 'a' band, and Professor Lowell contends that this can only be due to water vapour in the atmosphere of Mars.
"Professor Campbell has, however, made similar experiments, and is of opinion that Professor Lowell has been deceived by the water vapour in our own atmosphere. Thus the matter stands at the present time, and we must await the result of further investigation before we can consider the matter settled.
"I, however, regard it as a certainty that improved means will definitely show that water vapour undoubtedly exists in the Martian atmosphere, and it is not unlikely that other constituents of that atmosphere may also be identified, and possibly even the relative quantities may be ascertained."
John here remarked that he had read of it being contended that life could not exist on Mars because as water would boil at a temperature a hundred degrees lower than it did on the earth, it would be impossible to boil a potato properly, or make a good cup of tea. He thought, however, that if water boiled at such a low temperature, then the proportion of water vapour in the air would be increased, as evaporation would be more rapid than on the earth.
"Undoubtedly so," I replied. "The first argument, however, is very weak. For many thousands of years the people on the earth not only managed to live, but attained a high state of civilisation, yet we have no reason to believe that they ever ate potatoes or drank tea! Even in England we have only known and used these articles for about three hundred years! The inhabitants of any world would be suited to their environments.
"The polar-caps on Mars are shown on very early drawings of the planet; but, up to the year 1877, little was known of the general surface details beyond the fact that the general colour was orange-red, diversified by dark patches of blue-green in some parts, and some narrow, serpentine markings here and there. All these markings are now much more accurately drawn, as the result of more careful and continuous observation. Sir William Herschel suggested that the red colour was attributable to the vegetation of Mars being red, instead of green as on our earth; but it was generally considered that the red areas indicated land and the dark areas water. The work of our modern observers has, however, resulted in a general revision of our ideas on these points.
"It had long been reasoned that, as the earth was accompanied by a moon, and Jupiter had at least four, Mars, the intermediate planet, might be expected to possess a satellite. The planet itself being small, its moon would probably be very small, and likely to be overlooked when observing with the telescope, because its light would be overpowered by the light of the planet, which would make the telescopic field of view very bright. Up to the year 1877 the most powerful instruments had been used without success in the search for the supposed satellite.
"In that year Mars made an exceptionally near approach to the earth, and Professor Asaph Hall, of Washington Observatory, took up the search, using a splendid refracting telescope having an object-glass 26 inches in diameter. The methods he adopted were rewarded with success, for he discovered not only one, but two satellites of Mars, and they were given the names of Phobos and Deimos.
"Both these satellites are very close to the planet and extremely small, Phobos being less than 4000 miles from the planet's surface, and Deimos only 12,300 miles from it. As seen in the telescope, they are very faint points of light which cannot be measured by ordinary means, and the estimation of their size was a matter of great difficulty.
"Professor Langley gives an interesting account of the endeavour to estimate their size by the amount of light reflected, as compared with the light afforded by our own moon when full. It was a most difficult task, as the comparison had to be made by means of tiny holes drilled in metal plates; and for a long time it was impossible to find a workman who could drill a hole sufficiently small for the purpose, although one of those employed had succeeded in drilling a hole through a lady's thin cambric needle from end to end, thus converting it into a tiny steel tube. One would have thought such a feat impossible; yet what was now required was a hole smaller than the one thus made through the tiny needle."
"My word!" said M'Allister, "I would like to see the mon who did that piece of work, and shake hands with him; he must be a rare clever fellow!"
"Yes," said John, "and I would like to see the drill he used; for such a long and extremely slender tool, to be effective, must be as clever a piece of work as the steel tube."
"I may tell you," I proceeded, "that success was at last attained; and as a result of the comparison of our moon's light with that of Deimos, it was shown that if the general surface brightness of the latter were equal to that of our moon, then Deimos must be only 18 miles in diameter, or about a 15,000th part of the area of our moon's disc.
"To state the matter in another way--supposing our moon were only 18 miles in diameter, and was removed to the same distance as Deimos is from us, then it would appear only the very faint point of light that Deimos appears when viewed through the telescope.
"By the same means Phobos, the satellite nearest to Mars, was estimated to be about 22-1/2 miles in diameter. These dimensions, however, depend on the brightness of these satellites being exactly the same as the general brightness of our moon; and later experiments have fixed the sizes as 36 miles for Phobos, and 10 miles as the diameter of Deimos.
"I will not detain you much longer on this subject, as we shall be able to discuss it further when we arrive upon Mars; but I may now mention that, in one respect, the little satellite named Phobos is unique. It is the only satellite we know of which revolves round its primary planet in less time than it takes the planet itself to make one revolution on its axis.
"Mars revolves on its axis in 24 hours, 37 minutes, and 22 seconds, thus the 'day' on Mars is nearly 38 minutes longer than our 'day.' Phobos revolves round the planet in the very short period of 7 hours, 39 minutes, and 14 seconds, and therefore makes more than three complete revolutions round the planet in the course of a single Martian day. The peculiar phenomena to which this very rapid motion gives rise, and the numerous eclipses which occur, will be matters of great interest to us all when we reach Mars. Our moon, as you know, takes a month to make one revolution round the earth."
"Professor," said John, "when we get to Mars, it will be rather a curious experience for us to see two moons shining in the sky at the same time!"
"My word!" exclaimed M'Allister, "two moons shining at once! If I go out and see such a sight as that, I shall think the whisky has been a wee bit too strong for me!"
"Well," replied John, "if your usual drink has the effect of making you see double, take good advice, and leave the whisky severely alone when you are on Mars, or else you will be seeing four moons all at once, and receive such a shock that you will never get over it!"
M'Allister laughed pleasantly as John said this. He is a real good fellow, and takes all John's chaff with the utmost good-humour; but, in justice to him, I must say that, although he sticks to his national drink like a true Scot, I have never once seen him any the worse for it. He knows his limitations, and always keeps within them.
THE DISCOVERY OF LINES UPON MARS--THE GREAT MARTIAN CONTROVERSY.
After the little interlude with M'Allister, I resumed my remarks by saying that "The year 1877, so memorable for the near approach of Mars and the discovery of its two tiny satellites, was also the year in which a still more important discovery was made--a discovery, in fact, which has much enlarged our knowledge of the planet, and has also resulted in an entire revision of our conceptions respecting it.
"An Italian astronomer, Signor Schiaparelli, took advantage of the favourable position of Mars to observe it very carefully, and some time afterwards announced that he had seen upon its surface a number of very fine lines which had not previously been noticed, and these he had carefully charted upon his drawings and maps.
"This announcement started one of the most acrimonious discussions that the astronomical world has ever known; and although it is now over thirty years since it commenced, astronomers are still divided into two parties--one accepting the lines as demonstrated facts, the other either denying their existence, or endeavouring to explain them away by various more or less ingenious or fanciful theories.
[Illustration: From a Globe made by M. Wicks Plate VIII MARS. MAP I.