The Discovery Of Lines Upon Mars-the Great Martian Controversy

: To Mars Via The Moon

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.

r /> "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.


In all these maps the south is at the top. The dark shaded portions are

vegetation, mostly on old sea-beds. The fine lines are the canals, and

the round dots the oases. The light areas are deserts. Longitude "0" is

seen on the Equator between the two forks of the "Sabaeus Sinus."]

"When Signor Schiaparelli's statements and drawings were first

discussed, it was declared by some to be quite impossible that these

fine lines could really have been seen by him: either his eyes must have

been overstrained, or he claimed to see more than he actually did see.

So warm did the discussion become that he soon withdrew from it

altogether, but devoted himself to his work. As time went on, he not

only verified his previous discoveries, but found numerous fresh lines,

all of which appeared to run straight and true over many hundreds of

miles on the planet.

"Milan then had a good clear atmosphere which was favourable for the

observation of delicate planetary markings, and other observers who were

well situated were able to see and draw many of the lines which

Schiaparelli had discovered.

"It was, however, contended that such lines could not have any real

existence, as it was asserted that they were too straight. It is quite

true that straight lines on a rotating globe would appear curved when

seen from some points of view, but if the objectors had carefully

studied complete sets of drawings, they would have seen that the lines

did assume a curved form in certain aspects of the planet.

"Then the very same people who denied the actuality of the lines because

they were too straight, eagerly took up a suggestion that they were not

actually narrow lines, but the edges of diffused shadings on the planet,

apparently quite oblivious of the fact that the same objections must

apply to them. Moreover, if there was difficulty in accepting the

actuality of narrow lines, there must be immensely greater difficulty in

believing that shadings could, in such a very large number of cases, all

end in straight lines many hundreds or thousands of miles long, and

always appear uniformly true, no matter upon what portion of the disc

they might be seen, and whatever might be the angle of illumination.

"Besides, only a small proportion of the lines are connected with

shadings. The shadings are more likely to be the result of the canals

than the cause of the formation of illusory lines in so many cases.

"I have listened to many of these discussions, and have often been much

amused at the tangle of inconsistencies in which some have involved

themselves, by taking up fresh theories without regard to their previous


"As time went on each opposition of Mars brought the discovery of fresh

lines, and numerous observers confirmed the reality of Schiaparelli's


"Professor Lowell, the well-known American astronomer, took up the study

of Mars in a most thorough and systematic manner, and has since

practically made it his life's work. An observatory was built at

Flagstaff, Arizona, far away from towns and smoke, at an altitude of

over 6000 feet above the sea-level, the site being specially selected on

account of the clearness and purity of its atmosphere; while the

observatory, being high up above the denser and more disturbed strata of

air, afforded the most favourable situation possible for the proper

observation of delicate planetary detail.

"There he continued the work which Schiaparelli had commenced, and,

together with the colleagues with whom he has been associated, has, by

long-continued and most systematic work, added greatly to our knowledge

of Mars. Year after year has seen the addition of more lines on our maps

of the planet, whilst many interesting discoveries have been made-one

being that some of the fine lines were double, the second line always

being equidistant from the first one throughout its whole length, no

matter whether the lines were straight or curved.

"This caused a further outcry of objection. The observers were told that

they had been overstraining their eyesight so that they 'saw double,'

and also that they had been using telescopes not properly focussed. Such

objections seem almost beyond argument, for no practical observer could

use an improperly focussed instrument without at once discovering the


"Besides, if the double lines were the result of eye-strain, or any

other defect which might cause such illusions, all the lines would have

been seen double, or at least all the lines running at the same angles;

but as a matter of fact only a very small proportion of the lines were

so seen, and it made no difference what position they occupied on the

disc, or at what angles they were presented. Some of the doubles were,

in fact, curved lines; and another point was that in some cases they

were only doubled at certain seasons of the year.

"Other observers who saw the lines were charged with having studied the

maps of Schiaparelli and Lowell until they had become obsessed with the

lines, and when they looked through the telescope simply fancied they

saw them!

"In England our atmospheric conditions are seldom really favourable to

the proper seeing of the finer detail, and the very faint lines cannot

be seen at all. The lines that are visible do not appear thin and sharp

as they do to observers in more favoured climes, but rather as diffused

smudgy lines, and so they are drawn by the observers. On a few

occasions of exceptionally good seeing they have, however, been seen and

drawn as finer and sharper lines.

"The visibility of the lines was, however, confirmed by so many

observers of known integrity, and from so many different parts of the

world, that the objectors were at last compelled to abandon the position

they had occupied. Then a new theory was started, viz. that the lines

were actually seen but did not actually exist, being really optical

illusions arising from the apparent integration, or running together in

linear form, of various small disconnected markings which were viewed

from beyond the distance of clear seeing.

"The manner in which it was sought to prove the correctness of this

theory appeared to me at the time (and still does so) as most weak and

fallacious, and certain experiments I made only strengthened that

opinion. However, scientific people accepted it as proof.

"In making this experiment schoolboys were seated in rows at different

measured distances from a map of Mars, which they were told to copy. The

map showed all the well-known dark patches and markings, but no fine

lines. About the places where some of those lines should have been,

dots, curls, wisps, &c., were inserted at irregular distances, and not

always exactly where the lines should have been shown. The inevitable

result was that the boys who were too far away to see clearly saw these

small markings as continuous straight lines, and so drew them. In the

circumstances they could not do otherwise; for if sufficient marks were

inserted nearly in alignment, they would necessarily produce the effect

of lines.

"These drawings were then acclaimed as proving that the lines seen on

Mars were only discrete markings viewed from beyond the distance of

clear seeing, and that the network of lines seen and drawn by so many

skilled and careful observers of Mars had no actual existence upon the

planet. Thus all their work was completely discredited.

"Experiments like these could not possibly prove any such thing, because

it would be easy to insert in a map various markings which, when viewed

from a distance, would appear to form almost any design that one might

choose to depict. Any desired effect might thus be obtained; and I have

seen many pictures so formed in which the illusion was perfect. When

viewed from a distance each appeared to be a picture of something

entirely different from what was seen when it was viewed from a near


"The linear illusion could not arise from a mere multiplicity of faint

scattered markings, but all the more conspicuous markings must be in

alignment. It seems impossible to imagine that so many hundreds of lines

on Mars could thus fortuitously be formed by illusion, and every line

be connected to some definite point at each end.

"To argue that because illusory lines can be formed as in these

experiments proves that the Martian lines are also illusions is claiming

far too much. For instance, if I drew what was actually a map of South

Africa, and was so seen at close quarters, yet in consequence of the

insertion of numerous small marks and shadings formed a portrait of Lord

Blank when viewed from a distance, it would be very far indeed from

proving that every map of South Africa was a portrait of the noble lord,

or that his portraits were all maps of South Africa.

"Moreover, as I myself saw, some of the boys were so unskilled that they

had not even drawn correctly the outlines of the dark patches about

which there was no dispute.

"It is obvious that such erroneous and unreliable work as this could not

be regarded as evidence upon which truly scientific argument could be

founded for the purpose of deciding such a contentious question; yet

mainly upon this very slender and unreliable evidence meetings of two of

our leading astronomical associations endorsed the illusion theory, and

for a long time it held the field.

"M. Flammarion made some similar experiments in Paris, and even inserted

spaced dots along the sites of canal lines on the map put up as a copy,

yet not one boy drew a canal. M. Flammarion evidently was rather too

sparing with his dots and marks.

"A long series of experiments was carefully carried out by Professor

Lowell and his colleagues, from which it was deduced that if in any line

on Mars there was a gap of sixteen miles in length, our present

telescopes would suffice to discover it. It is most improbable that in

so many hundreds of lines, several of which are over two thousand miles

in length, there would not be numerous gaps over sixteen miles long if

the lines were made up of separate markings.

"Yet it is found that every line is perfect in its continuity, and not

only so, but uniform in width throughout its whole length, which would

be impossible if the lines were made up of separate markings not in


"The illusion theory may, however, to a certain extent be correct, but

this will prove exactly the opposite of what its supporters contend. It

appears to have been quite overlooked that as there are so many

thousands of miles of canals it is utterly impossible to suppose that

the vegetation, which is all that we really see, is continuous and

without breaks. It would indeed be most extraordinary if there were not

very many long stretches of land which, for some natural or utilitarian

reasons, were either bare of vegetation or so sparsely covered as to

appear bare when viewed from the earth through a telescope. Some parts

of the canals in hilly or rocky ground may pass through tunnels, and

thus cause apparent gaps in the lines; or ground may be incapable of

bearing vegetation, or purposely left fallow.

"It would, therefore, be no matter of surprise if more powerful

instruments should, in moments of perfect seeing, reveal numerous

apparent gaps in the lines. So far from proving they were not canals,

such gaps are exactly what we should expect to find in connection with

canals; and the lines would probably appear as irregular light and dark

patches in alignment, because we do not see the canals themselves, but

only the vegetation on the land which they traverse. Probably there are

also many oases yet to be discovered along the canal lines.

"As I have already stated, it was asserted that the double lines were

illusions arising from the causes already mentioned, with the probable

addition of eye-strain and bad focussing. Assuming that the single lines

are, as it is declared, illusions, we are confronted with the

assumption that the doubles are illusions of illusions, and this is more

than I can follow, it seems so improbable.

"Professor Lowell has devoted some sixteen years to close and continuous

observation of Mars whenever it has been in a position to be observed,

and many thousands of drawings have been made, the results being plotted

down on a globe. In reply to the statements of occasional observers that

the lines cannot be seen, he testifies that they are not difficult to

see; and that any one who saw them in his exceptionally good atmosphere,

and through his instruments, could have no doubt of their actuality. He

rather caustically, but very justly, remarks in one of his books that

his many years of personal experience in viewing these lines almost

entitle him to an opinion on the subject equal to those who have had

none at all!

"The proof of their existence, however, no longer rests only on the

corroborative evidence of other observers, for, after years of

experiment, Professor Lowell and his staff have succeeded in taking

direct photographs of Mars, which show several of the disputed lines.

One would have thought that would settle the question, but, although

some of the more reasonable of the objectors have been convinced by the

evidence of the photographs, many others still maintain their attitude

of scepticism, especially those who have not themselves seen the

photographs. They declare it to be quite impossible for any such

photographs to be taken, because our atmosphere would prevent any

photographic definition of fine detail on such small pictures; yet about

ten thousand of these tiny photographs were taken during the near

approach of Mars in 1907.

"As I possess a number of these photographs I can testify that they do

show some of the lines, and persons who disbelieved have expressed

surprise at their excellence. Success was only obtained by means of

specially sensitised plates, for the ordinary photographic rays and

ordinary plates were found useless, whilst the process of photographing

so small and distant a planet is surrounded with difficulties.

"Even when attached to a telescope giving an equivalent focal length of

nearly 150 feet, the camera only gives a very tiny image of the planet.

The lighting of the small image is faint, but if additional power were

used on the telescope to obtain a larger image, then its light must be

still fainter, and thus a longer exposure would be required to obtain a

picture on the plate. As Mars moves in its orbit and rotates on its

axis, and our atmosphere is subject to continual movement and

disturbance, any long exposure would result in a blurred picture, which

would show no fine detail. So, as a short exposure is essential, only a

small picture can be taken. Nothing is gained by any subsequent great

enlargement of the picture, because the grain of the film of a quick

plate is coarse; and, if enlarged, this also blurs out the detail.

"Having regard to all the difficulties which had to be surmounted, it

was a great and undoubted triumph to secure detail on such tiny

photographs of this distant world. As time goes on improvements will

probably be effected and still better pictures secured; but enough has

now been accomplished to prove that the lines cannot be illusions, but

really exist upon the planet. If the eye can be deceived in this

respect, the camera cannot.

"When Professor Lowell first took up the work of Martian observation

only 113 lines had been discovered by Schiaparelli, but the number has

gradually been added to from time to time, as the result of the work

done at Flagstaff Observatory and elsewhere, and has now reached a total

of considerably more than 600, the lines forming a fine network

extending all over the planet.

"Mr. Slipher, who accompanied Professor Todd's expedition to Alianza in

Chili, at the opposition of 1907, together with the observers at

Flagstaff, discovered no less than 85 new canals, including some

doubles, nearly all being in the more southern portions of the southern


"In addition to the discovery of so many fine lines, we also owe to the

acumen of Professor Lowell a reasonable explanation of what they really

are. Schiaparelli termed them 'canali,' an Italian term for 'channels,'

but, popularly, this soon became corrupted into the term 'canals,' and

this has turned out to be a much more appropriate word than such

corruptions usually are.


The Solis Lacus is seen as an oval patch near the top, and many long

canals, some double, are shown. A very large proportion of the area on

this map is desert land.]