THE PHOTOGRAPH IN ASTRONOMY 
occurring in the peculiar network of 
markings which geometrically thread 
the planet’s surface. Critical and serial 
observations embracing years of study 
of the planet by the keen eye of Dr. 
_ Lowell have revealed a close connection 
between the melting of the polar snows 
and the intensification of the canal sys- 
tem. This development of the marks of 
vegetation follows the passing of the 
sun from one hemisphere of the planet 
over the other and is most intense during 
the Martian spring and summer seasons. 
Mars is in a more advanced stage of 
planetary evolution than the earth and 
it has but a meager supply remaining of 
either air or water. Dr. Lowell believes 
that the numerous linelike markings seen 
there are those of vegetation growing 
by an enforcedly constructed irrigation 
system. Two significant facts found by 
observation support his theory: first, 
the marked geometric directness of the 
lines — no natural causes can account for 
them; second, the characteristic manner 
in which they develop with the seasons 
and the melting of the snow-caps. 
That the canals and oases do change 
markedly in intensity from time to time, 
is evidenced, directly and indirectly, by 
the observations of a number of astron- 
omers. The photographs of the planet 
also prove this. As far back as 1877 
Schiaparelli observed their disappear- 
ance and subsequent reappearance which 
he attributed to the presence of Martian 
clouds but it is now known that clouds 
never occur on Mars sufficient to obscure 
such surface details. In fact clouds are 
very rarely indeed observed there and 
when they do appear, they are seen only 
as dust storms along the planet’s termi- 
nator. It is clear therefore that the 
changes he saw in the intensity of the 
canals were not apparent and due to 
clouds as he thought, but real and due 
to seasonal variations in the vegetation. 
219 
Ever since Schiaparelli discovered 
the canals a spirit of skepticism, although 
not general, has existed regarding their 
reality and the observations of those who 
have seen them have met with consider- 
able criticism. Various theories have 
been advanced to explain them as illu- 
sions, but these theories suffered sure 
and sudden destruction when in 1905 
Mr. Lampland with camera and methods 
of his own design first succeeded in 
photographing them. Subsequent im- 
provements of the method brought better 
results and during the succeeding oppo- 
sitions of the planet a majority of the 
canals and oases have left their imprint 
on the photographic plate. However it 
is to be remembered that seeing with the 
eye is almost instantaneous, while with 
the photographic emulsion frequently a 
time exposure is required. Because of 
this, and the fact that even in the most 
tranquil air the telescopic image remains 
quiet but for a very short period of time, 
the photographic image stands at a 
great disadvantage, being a poor average 
picture of the planet at that moment. 
The importance of these Martian 
discoveries has been indicated and em- 
phasized by the denunciation they have 
called forth. It is the old story over 
again of the reception of an advanced 
idea, the same intellectual inquisition 
which scouted the discovery by Roemer 
of the velocity of light, and refused 
publication to Mayer’s and then Helm- 
holtz’s detection of the law of the con- 
servation of energy. Every new idea 
in science, Huxley said, starts as a myth 
to end as a superstition. The very same 
cast of mind that rejected the conserva- 
tion of energy for publication in the best 
physical magazine of Berlin because of 
its supposed absurdity, when it was 
young, is proclaiming it, now that it is 
old, the greatest scientific advance of 
the nineteenth century. 
