OBSERVATION
What to look for . . . We may not see what we do not expect to see
. . . Lenses reveal worlds great and small otherwise unseen . . .
Observers of the heavens and of seashore life . . . Collections aid
discovery . . . Happy accidents turned to profit . . . Value of a
fresh eye . . . Popular beliefs may be based on truth . . . An
engineer taught by a bank swallow.
Ability to observe is an unfailing mark of an inventor or discoverer: it
is quite as much a matter of the mind as of the eye. A botanist, keenly
alive to varieties of hue, of form in leaves, tendrils, and petals may
not give a second glance to stratifications which rivet the gaze of a
geologist for hours together. Each sees what he knows about, what he is
interested in, what he brings the power and desire to see. When Faraday
was asked to witness an experiment he always said: “What is it that I am
to look for?” He knew the importance of concentrating his attention on
the very bull’s eye of a target.
How much goes to sound observing is thus stated by John Stuart
Mill,--“The observer is not he who merely sees the thing which is before
his eyes, but he who sees what parts the thing is composed of. One
person, from inattention, or attending only in the wrong place,
overlooks half of what he sees; another sets down much more than he
sees, confounding it with what he imagines, or with what he infers;
another takes note of the _kind_ of all the circumstances, but being
inexpert in estimating their degree, leaves the quantity of each vague
and uncertain; another sees indeed the whole, but makes such an awkward
division of it into parts, throwing into one mass things which require
to be separated, and separating others which might more conveniently be
considered as one, that the result is much the same, sometimes even
worse than if no analysis had been attempted at all.”
How an explorer of ability may witness a new fact without realizing that
it points to a great industry, is shown in the case of Lord Dundonald.
In 1782, or thereabout, near Culross Abbey in Scotland, he built a
tar-kiln. Noticing the inflammable nature of a vapor arising during the
distillation of tar, the Earl, by way of experiment, fitted a gun-barrel
to the eduction pipe leading from the condenser. On applying fire to the
muzzle, a vivid light blazed forth across the waters of the Frith,
distinctly visible on the opposite shore. Soon afterward the inventor
visited James Watt at Handsworth, near Birmingham, and told him about
the gas-lighting at the kiln, but his host paid no attention to the
matter. His assistant, William Murdock, however, was impressed by the
story, and some years later applied gas to the illumination of the Soho
works where Watt’s engines were built. This was the beginning of
gas-lighting as a practical business.
Professor Adam Sedgwick, of Cambridge University, famous as a geologist,
and Charles Darwin once took an excursion in Wales amid markings of
extraordinary interest which neither of them noticed. Darwin tells us:
“I had a striking instance of how easy it is to overlook phenomena,
however conspicuous, before they have been observed by any one. We spent
many hours at Cwm Idwal, examining the rocks with extreme care, as
Sedgwick was anxious to find fossils in them, but neither of us saw a
trace of the wonderful glacial phenomena all around us; we did not
notice the plainly scored rocks, the perched boulders, the lateral and
terminal moraines, yet these phenomena are so conspicuous that, as I
declared in a paper published many years afterward, a house burnt down
by fire could not tell its story more plainly than did this valley. If
it had been filled with a glacier, the phenomena would have been less
distinct than they now are.” At a later day when Darwin’s powers of
observation had become acute in the highest degree, he noticed a bird’s
feet covered with dirt. Rather a common fact, not worth dwelling on,
earlier observers had supposed. Not so thought Darwin. He carefully
washed the bird’s feet, and planting the removed solids he was rewarded
with several strange plants brought from afar by his winged visitor.
A cousin to Charles Darwin, Francis Galton, is an investigator of
eminence. In a study of visual memory, a faculty in which observation
bears its best fruits, he says:--
“It is a mistake to suppose that sharp sight is accompanied by clear
visual memory. I have not a few instances in which the independence of
the two faculties is emphatically commented upon; and I have at least
one clear case where great interest in outlines and accurate
apprehension of straightness, squareness, and the like, is unaccompanied
by the power of visualizing.”
A new instrument, machine or engine is imagined by its creator long
before it takes actual form; everything he sees that will be of help he
builds at once into his design, everything else, however interesting in
itself, he passes with a heedless eye.
Think Birds and You Shall See Birds.
“If we think birds, we shall see birds wherever we go,” says John
Burroughs. An observer faithful and accurate in noticing birds and
beasts, rocks and leaves, may come at last upon a flower which opens a
sphere of knowledge wholly new, as when the round-leaved sun-dew was
first observed to entrap and feed upon insects. Much, also, depends upon
comparisons such as occur only to a mind at once broad and alert. One
may notice in spring and early summer a few leaves growing directly from
the trunk of a tree, sometimes near the ground. In maples these leaves
are decidedly narrower than those growing from branches in the usual
way, and they often have a reddish tinge. Comparing a variety of such
leaves with fossil impressions of allied species, Professor Robert T.
Jackson of Boston came upon an interesting discovery. He found that
these sporadic leaves closely resemble those borne by the remote
ancestors of our present trees: they are the lingering reminders of a
far distant day.
An observation equally keen saved the orange groves of California from
destruction by the fluted scale insect. In 1890, or thereabout, the
orange growers in their extremity sought the advice of Professor C. V.
Riley, entomologist to the Department of Agriculture at Washington. He
asked: “Where did the pest come from?” “Australia,” was the answer. “Is
it much of a nuisance there?” “Not particularly.” “Then what keeps it
down, what preys upon it?” “Nothing specially,” was the response.
Dissatisfied with this answer, Professor Riley sent to Australia a
trained entomologist and acute observer, Mr. Albert Koebele, who
gathered various insects noticed as preying upon the fluted scale.
Distributing these upon his arrival in California he was fortunate
enough to find that one of his assisted emigrants, a lady bird, _Vedalia
cardinalis_, fed so ravenously upon the fluted scale as to restrict its
ravages to quite moderate proportions.
It was an equally disciplined eye which in the laboratory first noticed
that air is non-conducting until traversed by an X-ray, when it becomes
conducting in a noteworthy degree. The field of radio-activity, at which
we have glanced in this book, owes its cultivation to observers keen to
note phenomena utterly unlike those before dwelt upon by the human eye.
Often close observers learn what would never be imagined as possible: in
rifle-making the tendency of the drills, which revolve nearly a thousand
times a minute, to follow the axial line in a revolving bar is a fact
which may be accounted for after observation, but which no one would
predict.
One day on the Glasgow and Ardrossan Canal a spirited horse took fright;
it was then observed, with astonishment, that a boat, the “Raith,” to
which it was attached, for all its increased speed, went through the
water with less resistance than before. The vessel rode on the summit of
a wave of its own creation with this extraordinary effect. The “Raith,”
said Mr. Scott Russell, “weighed 10,239 pounds, requiring a force of 112
pounds to drag it at 4.72 miles an hour; 275 pounds at 6.19 miles an
hour, and but 268-1/2 pounds at 10.48 miles per hour.” Thus
paradoxically was reversed the rule that the resistance of a vessel
increases rapidly as she is moved through the water. Mr. Russell
added:--“Some time since a large canal in England was closed against
general trade by want of water, drought having reduced the depth from 12
to 5 feet. It was then found that the motion of the light boats was more
easy than before; the cause was obvious. The velocity of the wave was so
much reduced by the diminished depth, that, instead of remaining behind
the wave, the vessels rode on its summit.”
The Mississippi Jetties of James B. Eads.
One of the most difficult problems ever solved by an American engineer
was the making navigation safe for vessels of fairly deep draft in the
lower branches of the Mississippi. The difficulties were overcome by
James B. Eads, of St. Louis, in his system of jetties. He remarked, says
his biographer, Mr. Louis How, that other things being equal, the amount
of sediment which a river can carry is in direct proportion to its
velocity. When, for any reason, the current becomes slower at any
special place, it drops part of its burden of sediment at that place,
and when it becomes faster again it picks up more. Now, one thing that
makes a river slower is an increase of its width, because then there is
more frictional surface; and contrariwise, one of the things that makes
it faster is a decrease of its width. Narrow the Mississippi then, at
its mouth, said Eads, and it will become swifter there, and consequently
will remove its soft bottom by picking up the sediment (of which it will
then hold much more), and by carrying it out to the gulf, to be lost in
deep water and swept away by currents, you will have your deep channel.
In other words, if you give the river some assistance by keeping its
current together, it will do all the necessary labor and scour out its
own bottom. This sound reasoning, based upon observation as sound, was
duly embodied in a series of jetties which have proved successful.
Observation Suggests an Experiment.
Such a river as the Mississippi taking its source through an alluvial
plain, has bends which go on increasing by the wearing away of the outer
banks, and the deposition of mud, sand and gravel on the inner bank. In
1876 at the Glasgow meeting of the British Association for the
Advancement of Science, Professor James Thomson showed a model which
made the phenomena of the case perfectly clear. A stream eight inches
wide and less than two inches deep, flowed round a bend. As it turned
this bend the water exerted centrifugal force, while a thin layer of the
water at the bottom, representing a similar layer close to a river-bed,
was retarded by its friction with the remainder of the stream, exerting
less centrifugal force than like portions of the larger body of water
flowing over it farther away from the bottom. Consequently the bottom
layer flowed in obliquely across the channel toward the inner bank;
rising up in its retarded motion betwixt the fast flowing water it
protected the inner bank from scour. At the same time this retarded
current brought with it sand and other detritus from the bottom, duly
deposited along the inner bank of the stream.
Instrumental Aids to Observation.
The powers of the eye, acute as they are, have narrow limits;
inestimable therefore is the value of the microscope, the telescope and
the camera which bring to view uncounted images otherwise unseen. Let us
remark how in the early days of instrumental aids a great observer just
missed noting a phenomenon of utmost importance,--the black lines of the
solar spectrum, upon which Fraunhofer, an optician of Munich, based his
spectroscope. In sending a solar beam through a lens and a prism Sir
Isaac Newton admitted the rays through an oblong slit at times as narrow
as one twentieth of an inch. He saw the familiar colors, from red to
violet, and nothing more. Even with a crown lens, such as he probably
used, four lines distinctly appear; that is, they appear to-day, to an
observer who is looking for them. In 1802 these lines were observed, as
far as we know, for the first time on record, by Dr. Wollaston, who drew
six of them in a diagram accompanying a paper in the Philosophical
Transactions. Four of these lines he regarded as boundaries of the
colors of the spectrum; of the other two lines he attempted no
explanation. He used prisms of various materials but found no alteration
in the lines while he studied a sunbeam. When he employed candles or an
electric light he found the appearances different, why, he could not
undertake to explain. In 1814, Fraunhofer observed these lines in
detail, mapped them, and proved that they identified elements long known
to chemists. As he built his spectroscope he gave the chemist, the
physicist and the astronomer an instrument of research worthy a place
beside either the microscope or the telescope.
Dr. Wollaston, in 1802, as we have seen stood upon the threshold of
spectroscopy without knowing it. During the same year he performed an
experiment which took him into the field of photography without his
recognizing the possibilities of that wonderful art. He took paper
which had been dipped in muriate of silver and caught on its surface
impressions of the ultra-violet light in a solar spectrum. These rays,
as rings, were reflected from a thin plate of air, as in the case of the
colors of thin plates, at distances corresponding to their proper places
in the spectrum. Thus was established the close analogy between rays
visible and invisible, and by a method destined to give mankind a
universal limner in light of all kinds, and in much radiance which is
not luminous at all.
Two Observers of the Skies.
Edward Emerson Barnard, of the Yerkes Observatory, Williams Bay,
Wisconsin, is in the first rank of living astronomers. Among his many
discoveries the most remarkable is that of the fifth satellite of
Jupiter at the Lick Observatory. His early work at the Vanderbilt
Observatory, Nashville, gave full promise of his later achievements. One
evening in November, 1883, he was observing an occultation of the
well-known star _Beta Capricorni_ by the moon. He had patiently waited
for his opportunity; such an occultation is best seen when the moon is a
small crescent, the star disappearing at the dark curve of the moon
where its beams do not overpower the feeble stellar ray. When the moon
passes between the eye and a fixed star, the disappearance of the star
is instantaneous. At the distance from which we look at it the star is a
point only, and as the moon has no atmosphere, the instant the edge of
the lunar surface touches the line joining the eye of the observer with
the star, it vanishes from sight. When the moon passed in front of _Beta
Capricorni_ Mr. Barnard noticed that instead of disappearing at once,
there was a sudden partial diminution of the light of the star, then a
total extinction of the remaining point. The interval between the
diminution and complete extinction of the light occupied only a few
tenths of a second, but it was long enough to put his keen mind upon
inquiry. Mr. Barnard in an astronomical journal called attention to the
phenomenon and suggested that instead of there being only one star, as
formerly supposed, there were really two stars so close together that in
an ordinary six-inch telescope, such as he had used, they appeared to be
one. He inferred also that one of the pair must be a good deal brighter
than the other, because at the beginning the change in brightness was
less than at the end. This surmise was soon afterward fully verified by
Mr. S. W. Burnham with the eighteen and one half inch equatorial of the
Dearborn Observatory at Chicago, revealing a close and unequal double
star which would have remained unresolved had he used a less powerful
instrument.
This Sherburne Wesley Burnham is the most successful discoverer of
double stars who has ever lived. “The extreme acuteness of vision,” says
Professor John Fraser, “which enables one to prosecute such research
with the highest success is a very rare gift; and the discovery of close
doubles, as in his case, is its severest test. To measure a star--that
is, to ascertain by means of the micrometer the distance and position
angle of the companion with reference to the principal star--is one
thing, and to find new and close doubles is a very different thing.
Baron Dembowski, the most noted measurer of double stars, had no success
as a discoverer, and confessed his inability to find new doubles. When,
however, a new double had been found by another observer, and the
distance and position angle of the companion approximately estimated, he
could readily find and accurately measure it. When Mr. Asaph Hall, in
1877, had found the two satellites of Mars and described their
positions, it was not difficult for any astronomer who had access to a
large Clark telescope to find them and see all that Mr. Hall had seen.
The whole difficulty was in seeing them for the first time. Besides the
ability to see a difficult object, there is required an intelligence and
experimental knowledge of the subject, which are as rare as the visual
faculty itself. Some of the lower animals have more acute vision than
human beings; but they do not know all they see, or understand relations
to other facts. They have plenty of sight, but they lack insight. Mr.
Burnham’s powers in both these respects is extraordinary.”
At the Cape of Good Hope Observatory remarkable observations of double
stars have been recorded. Sir David Gill, the director, says:--“At the
Cape Observatory, as has always been the case elsewhere, the subject of
double star measurement on any great scale waited for the proper man to
undertake it. There is no instance, so far as I know, of a long and
valuable series of double star discovery and observation made by a mere
assistant acting under orders. It is a special faculty, an inborn
capacity, a delight in the exercise of exceptional acuteness of eyesight
and natural dexterity, coupled with the gift of imagination as to the
true meaning of what he observes, that imparts to the observer the
requisite enthusiasm for double star observing. No amount of training or
direction could have created the Struves, a Dawes or a Dembowski. The
great double star observer is born, not made, and I believe that no
extensive series of double star discovery and measurement will ever
emanate from a regular observatory through successive directorates
unless men are specially selected who have previously distinguished
themselves in that field of work, and who were originally driven to it
from sheer compulsion of inborn taste.”
The Eye of a Naturalist.
It is sometimes said that the faculty of observation is a special gift
with limitations, that the naturalist sees bones, feathers, shells
because he is looking for them, while the armorer or the engineer but
seldom gives a second glance to anything but guns, girders, or
machinery.
To this rule we find striking exceptions. Edward S. Morse, of Salem,
Massachusetts, is the foremost American expert in Japanese pottery. As a
youth he was a railroad draughtsman in Portland, Maine, where his
ambidexterity with the pencil and his discoveries in natural history
brought him to the notice of Louis Agassiz. As a boy he was greatly
interested in the shells of his native State; before he left school he
had discovered and described a new species of land snail, _Helix
asteriscus_, which the older naturalists had regarded as the young state
of another and well-known species. At the same time he determined the
distinct character of a most minute species, _Helix minutissima_, which
had been described as such thirty years before, but which the later
authorities had believed to be the young of another species. This
faculty for discrimination led him to demonstrate a new bone in the
ankle of birds which Huxley, and others, had supposed to be a process
and not a separate bone. This discovery added another to the many
reptilian characters which have been disclosed in the anatomy of birds.
He also established beyond question that the brachiopods, always
believed to be mollusks, are not mollusks at all, but are related to the
worms. In Mr. Morse’s case we have either a man with a universal power
of observation, or enjoying distinct faculties of perception, each
usually appearing alone in an observer. Noticing a Japanese shooting a
bow and arrow one day he took up the study of the attitude of the hand
in pulling the bow. His memoir on this subject, with illustrations, has
attracted world-wide interest. Pursuing this theme he examined an
ancient object of bronze having three prongs, labeled as a bow-puller in
European museums, showing that it had no relation whatever with the bow.
Keenly susceptible to the beauty and variety of roofing tiles in Europe
and the East, he has for the first time given them classification, and
shown their ethnological significance. While teaching natural history at
the University of Tokio he brought together the Japanese pottery now
exhibited at the Museum of Fine Arts in Boston, unsurpassed as a
collection in the world. His eye was as sharp in reading a potter’s
mark, however worn and blurred, as when as a boy in Maine he defined
minute species of land shells.
The Value of Collections.
Altogether commendable is the spirit which leads a boy or girl to
collect and arrange shells, common wildflowers, seaweeds, and the
diverse minerals brought to light in a railroad cutting. What is thus
gathered, compared, and studied will leave a much deeper impression on
the memory than what is seen for a moment in a museum or a public
garden. And yet, to the profound student the museum is indispensable: he
gives weeks or months to the contents of its cases, supplementing what
he has learned in the field, by the seashore, in the woods. Take, for
example, protective resemblances, one of the most fascinating provinces
of natural history. Here is a hornet clear-wing moth. What has made it
look like a wasp? Both share the same field of life, and while the wasp
does not prey on the moth or in any perceptible way compete with it, the
two insects have a vital bond. In its sting the wasp has so formidable
and thoroughly advertised a weapon that by closely resembling the wasp
the moth, though stingless, is able to live on its neighbor’s
reputation, and escape attack from the birds and insects which would
devour it if they did not fear that it is a stinging wasp. So far is the
resemblance carried that when the moth is caught in the hand it curves
its body with an attitude so wasplike as seriously to strain the nerves
of its captor.
How came about so elaborate a masquerade? At first, ages ago, there was
a faint likeness between the moth and the wasp; any moth in which that
likeness was unusually decided had therein an advantage and tended to be
in some measure left alone by enemies. In thus escaping it could
transmit in an ever-increasing degree, its peculiarities of form and hue
to its progeny, until in the rapid succession of insect generations,
amid the equally rapid destruction of comparatively unprotected moths,
the present striking similarity arose. Instances of this kind abound,
forming some of the most attractive exhibits in the American Museum of
Natural History of New York, and other great museums. Mr. W. H. Bates,
who first explained these resemblances, did so as the result of
comparing many various examples preserved in his cabinets at home,
although, of course, his memory of habits observed in the field was
indispensable. His ample collections enabled him to bring into view at
once many captures separated by wide intervals of time and space. It was
the opportunity thus afforded of taking a comprehensive survey of
resemblances as a whole that led him to think out the underlying reason.
Accidental Observation.
Accident has played a noteworthy part in both discovery and invention.
Nathaniel Hayward long ago remarked that sulphur deprives rubber of
stickiness. Charles Goodyear one day combined some rubber and sulphur by
way of experiment; quite by accident he overturned part of the mixture
upon a hot stove. He saw in a moment that heat is essential to make
rubber insensible to both heat and cold: he had indeed discovered
vulcanization. Examples of this kind abound in the history of every art.
As far afield as the war on insect pests in France a priceless discovery
was hit upon unsought a few years ago. One autumn the vines were still
suffering from phylloxera when a mildew caused by a fungus began to do
serious damage to crops. Through the spraying of vines with blue-stone
to prevent pilfering of fruit, it was noticed that the fungus was
killed, leading to the most telling mode of attack on many of the pests
which assail leaves, flowers and fruit.
James Hargreaves once saw a spinning-wheel overturned, when both the
wheel and spindle continued to revolve on the floor. As he observed the
spindle thus changed from a horizontal to an upright position it
occurred to him that if a number of spindles were thus placed, side by
side, several threads might be spun at once instead of a single thread.
This was the origin of the spinning jenny; an invention which has
parallels in the multiple drills, the gang-saws, and other machinery
which take a task once executed by a single drill, saw or punch, and
simultaneously perform it with ten, twenty, or a hundred drills, saws,
or punches.
About thirty years before Josiah Wedgwood laid the foundation of his
future eminence, a chance observation gave rise to improvement in the
earthenwares of Staffordshire. A potter from Burslem, the centre of the
potteries and the birthplace of Wedgwood, in traveling to London on
horseback was detained on the road by the inflamed eyes of his horse.
Seeing the hostler, the horse-doctor of those times, burn a piece of
flint, and, having reduced it to a fine powder, apply it as a specific
to the diseased eyes, it occurred to the potter that this beautiful
white powder, if combined with the clay used in his craft, might improve
the strength and color of his ware. An experiment succeeded, and so
began English white ware, since manufactured on an immense scale.
More important than this discovery of a new use for flint powder was the
discovery, also accidental, of electro-magnetism by Professor Oersted of
Copenhagen. The incident is thus related in a letter to Michael Faraday
from Professor Christian Hansteen:--
“Professor Oersted was a man of genius, but he was a very unhappy
experimenter; he could not manipulate instruments. He must always have
an assistant, or one of his auditors who had easy hands, to arrange the
experiment; I have often in this way assisted him. In the eighteenth
century there was a general thought that there was a great conformity,
and perhaps identity, between the electrical and magnetical forces; and
it was a question how to demonstrate it by experiments. Oersted tried to
place the wire of his galvanic battery perpendicular (at right angles)
over the magnetic needle, but remarked no sensible motion. Once, after
the end of his lecture, as he had used a strong galvanic battery to
other experiments, he said, ‘Let us now once, as the battery is in
activity, try to place the wire parallel with the needle;’ as this was
done he was quite struck with perplexity by seeing the needle making a
great oscillation (almost at right angles with the magnetic meridian).
Then he said, ‘Let us now invert the direction of the current;’ and the
needle deviated in the contrary direction. Thus the great detection was
made; and it has been said, not without reason, that ‘he tumbled over it
by accident.’ He had not before any more idea than any other person that
the force should be transversal.”
Granting that many important discoveries thus come about in ways beyond
human foresight, accident alone will not produce an invention. As Dr.
Ernst Mach reminds us, in every such case the inquirer is obliged to
take note of the new fact, to recognize its significance, to detect the
part it plays, or can be made to play, in a new structure, or in a novel
and sound generalization. What he sees before him, others also have
seen, perhaps many times; he is the first to notice it as it deserves to
be noticed, simply because he has an eye earnestly desiring to behold
just such a fact as this and use it to bridge a gap either in art or
explanation.
Let us take a case where an accident, well observed, has meant a golden
discovery. One day during a trip on the Thames in a steamer propelled by
an Archimedean screw devised by Francis Pettit Smith, the propeller
struck an obstacle in the water, so that about one half of the length of
the screw was broken off; it was noticed that the vessel immediately
shot ahead at a much quickened pace. In consequence of this discovery, a
new short screw was fitted to the vessel and with this new propeller the
steamer went uniformly faster than before.
Perforated Sails for Ships.
In craft built ages before steamers were designed, fishermen have
observed that sails torn in the middle, if the rents were not too big,
were more effective than when new and whole. What thus began in sheer
wear, or accidental damage, is now imitated of set purpose. Under the
equator one may often see small craft whose sails are matting woven with
large openings, as the sailors say “to let out the wind.” The mariners
of Carthegena, St. Thomas, and other islands of the West Indies, know
that a ship goes better thus than if her sails were each one continuous
breadth of canvas. Japanese junks of clipper builds have sails made of
vertical breadths laced together so as to leave large apertures free to
the air. Why is this breeziness of structure profitable? Because against
the concave surface of an ordinary sail the wind rebounds so as to
hinder its impulsive effect; through an aperture the air rushes in a
continuous current and no rebound takes place. For a like reason, and
with similar gain, Chinese rudders are made with separated boards or
planks. The stream of water passing through such a rudder would exert an
undesirable back pressure in a rudder of solid form.
[Illustration: Perforated sails.
1, jib. 2, stay-sail. 3, square sail. 4, top sail. 5, sloop with
perforated sails.]
It would be interesting, and might prove gainful, to experiment with
perforated sails in sail-boats, ice-boats and wind-mills. In large
kites, sent to the upper air by meteorologists, it has been found
helpful to give the fabric a few small perforations.
Observations Must be Remembered and Compared: The Value of a New Eye.
It is not only necessary to observe if one would learn, one must
remember and compare observations. In a cycle of 223 lunations all the
motions of the moon are repeated; it is astonishing that astronomers in
Chaldea detected this period, exceeding eighteen years as it does. On
the other hand, one of the most striking phenomena of a solar eclipse,
its revelation of the solar corona, does not seem to have been noticed
until comparatively recent times. The first known record of it is by
Lobatchevsky, July 8, 1842.
There is value in the teaching which teaches the eye what to observe; at
times there is gain in a freshness of view unwarped by ideas as to what
deserves to be inspected and what does not. Dr. Priestley, one of the
founders of chemistry, says:--“I do not at all think it degrading to the
business of experimental philosophy to compare it, as I often do, to the
diversion of hunting, where it sometimes happens that those who beat the
ground the most, and are consequently best acquainted with it, weary
themselves without starting any game, when it may fall in the way of a
mere passenger; so that there is but little room for boasting in the
most successful termination of the chase.” True, yet this discerning eye
will always be found beside a brain of uncommon force and sweep. Mr.
Edwin Reynolds, of Milwaukee, as related in this book, never saw a
mining stamp until the morning when he planned a bold and profitable
simplification of it. Professor Alexander Graham Bell, who invented the
telephone, came to his triumph not as a disciplined electrician, but as
a student, under his father, of articulate speech and its transmission.
He has told me that had he known the obstacles to be surmounted, he
would never have begun his attack.
Professor Ernst Abbe, of Jena, who more than any other investigator is
to be credited with the production of Jena glass, was at the outset of
his labors quite ignorant of practical optics. But he had a thorough
mastery of mathematical optics, and this in due season enabled him to
revise the theory of the microscope, and to prescribe the conditions
according to which the manufacture of totally new kinds of glass should
proceed. Every one of these men, every peer they have ever had among the
volunteer forces of research, is far removed in native ability, in
plasticity of mind, from Priestley’s “mere passenger.” If ignorance by
itself were the chief qualification for discovery, science would long
ago have entered upon its golden age.
Any Observation May Have Value.
Michael Faraday, that consummate observer, held that at times the
observations of comparatively untrained men are well worth attention. In
one of his note-books he wrote:--“Whilst passing through manufactories
and engaged in the observance of the various operations of civilized
life, we are constantly hearing observations made by those who find
employment in these places, and are accustomed to a minute observation
of what passes before them which are new or frequently discordant with
received opinions. These are frequently the result of facts, and though
some are founded in error, some on prejudice, yet many are true and of
high importance to the practical man. Such of them as come in my way I
shall set down here, without waiting for the principle on which they
depend; and though three fourths of them ultimately prove to be
erroneous, yet if but one new fact is gathered in a multitude, it will
be sufficient to justify this mode of occupying time.”
Folk Observation Foreruns Science.
Often a conviction widely held by the plain people of a countryside is
based on many and sound observations, long before a scientific theory
accounts for the facts. For many generations there was a saying among
German peasants that when a storm is approaching a fire should be made
in the stove, with as much smoke as possible. Professor Schuster has
shown that this saying and the custom founded upon it are rational, as
the products of combustion and the smoke act as an effective conductor
to discharge the atmosphere slowly but surely. He quotes statistics
showing that out of each 1000 cases of lightning stroke, 6.3 churches
and 8.5 mills were struck, and but 0.3 factory chimneys. Only the
factories had fires burning.
A mighty work has been wrought by glaciers on the surface of our globe.
Long before this fact was discovered by professional geologists it was
clear to many of the plainer people. Jean de Charpentier, one of the
first propounders of the theory of glacial action now fundamental in
geological science, relates:--“When in the year 1815, I returned from
the magnificent glaciers of the valley of the Rhone, I spent the night
in the hamlet of Lourtier, in the cottage of Perraudin, a
chamois-hunter. Our conversation turned on the peculiarities of the
country, and especially of the glaciers which he had repeatedly explored
and knew most intimately. ‘Our glaciers,’ said Perraudin, ‘had formerly
a much larger extent than now. Our whole valley was occupied by a
glacier extending as far as Martigny, as is proved by the boulders in
the vicinity of this town, and which are far too large for the water to
have carried them thither.’” Charpentier adds that he afterward met with
similar explanations on the part of mountaineers in other sections of
Switzerland.
Cowpox was long observed by English country folk to be a preventive of
smallpox. It was in hearing a servant woman say so that Dr. Jenner was
drawn to the study which ended in his successful vaccinations, in all
the triumphs since won in this department of medical science. For two
thousand years the peasants of Italy have suspected mosquitoes and other
insects to be concerned in the spread of malarial and other fevers. It
remained for Dr. Ronald Ross in our day to prove that the suspicion was
founded in truth. In “The Naturalist in La Plata,” one of the best books
on natural history ever written, Mr. W. H. Hudson says:--“The country
people in South America believe that the milky secretion exuded by the
toad possesses wonderful curative properties; it is their invariable
specific for shingles--a painful, dangerous malady common amongst them,
and to cure it living toads are applied to the inflamed part. I
dare say learned physicians would laugh at this cure, but then, if I
mistake not, the learned have in past times laughed at other specifics
used by the vulgar, but which now have honorable places in the
pharmacopœia--pepsine, for example. More than two centuries ago, very
ancient times for South America, the gauchos were accustomed to take the
lining of the rhea’s (a large ostrich’s) stomach, dried and powdered,
for ailments caused by impaired digestion; and the remedy is popular
still. Science has gone over to them, and the ostrich-hunter now makes a
double profit, one from the feathers, and the other from the dried
stomachs which he supplies to the chemists of Buenos Ayres. Yet he was
formerly told that to take the stomach of the ostrich to improve his
digestion was as wild an idea as it would be to swallow birds’ feathers
in order to fly.”
Snake poison has long been used by the Hottentots as an antidote to
snake poison. With aid from the Carnegie Institution of Washington, Dr.
Hideyo Noguchi, of the University of Pennsylvania, has succeeded in
producing antivenins, to use the medical term, for the venoms of the
water-moccasin and _Crotalus adamanteus_ snakes, using the venoms
themselves in preparing his antidotes. He is continuing his researches
in this remarkable field of the healing art.
Kelp, as it drifts and sways in the Atlantic, attracts from the sea both
the iodine and the bromine dissolved in minute quantities in the
sea-water. This trait of fastening upon a particular and rare element is
displayed by plants on land as well as by sea-weeds. In the Horn silver
mine of Utah, the zinc mingled with the silver is betokened by the
abundance of a zinc violet, _Viola calaminaria_, a delicate cousin of
the pansy. In Germany this little flower was believed to point to zinc
deposits long before zinc was discovered in its juices. The late Mr.
William Dorn, of South Carolina, had faith in a bush of unrecorded name,
as declaring that gold veins stood beneath it: that his faith was not
baseless is proved by the large fortune he won as a gold miner in the
Blue Ridge country--his guide the bush aforesaid. Mr. Rossiter W.
Raymond, a famous mining engineer of New York, has given some attention
to “indicative plants” of this kind. He is of opinion that their
unwritten lore among practical miners, prospectors, hunters, and Indians
is well worth sifting.
He says:--“Judging from the general laws of the distribution of plants,
and from the analogy furnished by _Viola calaminaria_, we may expect
that an indicative plant will be, not a distinct species, but a variety
of some widely distributed species, the range of the species as a whole
being determined by general conditions of climate, altitude and soil,
while the characteristics of the variety are affected by causes peculiar
to the mineral deposit. Temperature and moisture, as Agricola long ago
pointed out, are among these causes, and color is one of the most
sensitive of their effects. It is quite reasonable to believe the soil
may affect the color of the plant absorbing it. On the other hand, it
is not certain, even if a plant is proved to indicate by color or other
peculiarities the presence of silver, that silver is the substance
actually entering into and altering the plant. The effect may be due to
some other mineral substances associated with the silver-ores; and our
silver-plant may be indicative of silver in a silver region only.”
Mr. Raymond remarks that a general relation between the flora and the
geological formation of any given district is a fact familiar to
field-geologists. Many plants, too, indicate the neighborhood of water.
A botanist knowing the root-length, water-requirements and habits of
different species can often determine from the surface vegetation, he
tells us, the nature, amount and distance of the underground
water-supply.[33]
[33] In his paper on “Indicative Plants,” published in the
Transactions of the American Institute of Mining Engineers, 1886,
Mr. R. W. Raymond illustrated in natural size _Viola calaminaria_,
_Amorpha crescens_, and _Erigonium ovalifolium_. His paper is
followed by the interesting discussion it called forth.
How observation may lead to a bold and successful experiment is told by
Mr. L. E. Chittenden, Register of the Treasury under President Lincoln,
in his Personal Reminiscences:--
A Lesson from a Bank-Swallow.
Between the Winooski Valley and Lake Champlain, north of the city of
Burlington, lies a broad sand plain high above the lake level, through
which the Central Vermont Railroad was to be carried in a tunnel. But
the sand was destitute of moisture or cohesiveness, and the engineers,
after expending a large sum of money, decided that the tunnel could not
be constructed because there were no means of sustaining the material
during the building of the masonry. The removal of so large a quantity
of material from a cut of such dimensions also involved an expense that
was prohibitory. The route was consequently given up and the road built
in a crooked ravine through the centre of the city, involving ascending
and descending grades of more than 130 feet to the mile. When the
railroad was opened these grades were found to involve a cost which
practically drove the through freights to a competing railroad.
There was at the time a young man in the engineers’ office of the
railroad who said that he could tunnel the sand bank at a very small
cost. He was summoned before the managers and questioned. “Yes,” he
said, “I can build the tunnel for so many dollars per running foot, but
I cannot expect you to act upon my opinion when so many American and
European engineers have declared the project impracticable.” The
managers knew that the first fifty feet of the tunnel involved all the
difficulties. They offered him, and he accepted, a contract to build
fifty feet of the structure.
His plan was simplicity itself. On a vertical face of the bank he marked
the line of an arch larger than the tunnel. On this line he drove into
the bank sharpened timbers, twelve feet long, three by four inches
square. Then he removed six feet of the material and drove in another
arch, just inside the first one, of twelve-foot timbers, took out six
feet more of sand, and repeated this process until he had space enough
to commence the masonry. As fast as this was completed the space above
it was filled, leaving the timbers in place.
Thus he progressed, keeping the masonry well up to the excavation, until
he had pierced the bank with the cheapest tunnel ever constructed, which
has carried the traffic of a great railroad for thirty years, and now
stands as firm as on its completion.
The engineer was asked if there was any suggestion of the structure
adopted by him in the books on engineering. “No,” he said, “it came to
me in this way. I was driving by the place where the first attempts were
made, of which a colony of bank-swallows had taken possession. It
occurred to me that these little engineers had disproved the assertion
that this material had no cohesion. They have their homes in it, where
they raise two families every summer. Every home is a tunnel,
self-sustaining without masonry. A larger tunnel can be constructed by
simply extending the principle, and adopting masonry. This is the whole
story. The bank-swallow is the inventor of this form of tunnel
construction. I am simply a copyist--his imitator.”