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_ROUGH WAYS MADE SMOOTH_




  ROUGH WAYS MADE SMOOTH

  A SERIES OF

  Familiar Essays on Scientific Subjects

  BY
  RICHARD A. PROCTOR

  [Illustration]

  _NEW IMPRESSION_

  LONGMANS, GREEN, AND CO.

  39 PATERNOSTER ROW, LONDON

  NEW YORK AND BOMBAY

  1903

  _All rights reserved_




  '_Let knowledge grow from more to more_'

  TENNYSON




PREFACE.


It is scarcely necessary for me to explain the plan of the present
work, because I have already--in introducing my 'Light Science
for Leisure Hours,' my 'Science Byways,' and my 'Pleasant Ways in
Science'--described the method on which, as I think, such treatises as
the present should be written. This work deals with similar subjects in
a similar way; but I think the experience I have acquired in writing
other works on the same plan has enabled me to avoid some defects in
the present work which I have recognised in the others.

The list of subjects indicates sufficiently the range over which the
present volume extends. Some of them might be judged by their names to
be in no way connected with science, but it will be found that none
have been treated except in their scientific significance, though in
familiar and untechnical terms.

  RICHARD A. PROCTOR.

  S.S. 'ARIZONA,' IRISH SEA
  _October 18, 1879._




CONTENTS.


                                                PAGE
  THE SUN'S CORONA AND HIS SPOTS                   1

  SUN-SPOTS AND COMMERCIAL PANICS                 26

  NEW PLANETS NEAR THE SUN                        32

  RESULTS OF THE BRITISH TRANSIT EXPEDITIONS      58

  THE PAST HISTORY OF OUR MOON                    81

  A NEW CRATER IN THE MOON                        98

  THE NOVEMBER METEORS                           111

  EXPECTED METEOR SHOWER                         117

  COLD WINTERS                                   125

  OXFORD AND CAMBRIDGE ROWING                    148

  ROWING STYLES                                  169

  ARTIFICIAL SOMNAMBULISM                        178

  HEREDITARY TRAITS                              205

  BODILY ILLNESS AS A MENTAL STIMULANT           236

  DUAL CONSCIOUSNESS                             259

  ELECTRIC LIGHTING                              289




ROUGH WAYS MADE SMOOTH.




_THE SUN'S CORONA AND HIS SPOTS._


One of the most important results of observations made upon the eclipse
of July 29, 1878, indicates the existence of a law of sympathy, so to
speak, between the solar corona and the sun-spots. The inquiry into
this relation seems to me likely to lead to a very interesting series
of researches, from which may possibly result an interpretation not
only of the relation itself, should it be found really to exist, but
of the mystery of the sun-spot period. I speak of the sun-spot period
as mysterious, because even if we admit (which I think we cannot do)
that the sun-spots are produced in some way by the action of the
planets upon the sun, it would still remain altogether a mystery
how this action operated. When all the known facts respecting the
sun-spots are carefully considered, no theory yet advanced respecting
them seems at all satisfactory, while no approach even has been
made to an explanation of their periodic increase and diminution in
number. This seems to me one of the most interesting problems which
astronomers have at present to deal with; nor do I despair of seeing
it satisfactorily solved within no very long interval of time. Should
the recognition of a sympathy between the corona and the sun-spots be
satisfactorily established, an important step in advance will have been
made,--possibly even the key to the enigma will be found to have been
discovered.

I propose now to consider, first, whether the evidence we have on this
subject is sufficient, and afterwards to discuss some of the ideas
suggested by the relations which have been recognised as existing
between the sun-spots, the sierra, the  prominences, and the
zodiacal light.

The evidence from the recent eclipses indicates beyond all possibility
of doubt or question, that during the years when sun-spots were
numerous, in 1870 and 1871, the corona, at least on the days of the
total solar eclipses in those years, presented an appearance entirely
different from that of the corona seen on July 29, 1878, when the sun
was almost free from spots. This will be more fully indicated further
on. At present it is necessary to notice only (1) that whereas in 1870
and 1871 the inner corona extended at least 250,000 miles from the
sun, it reached only to a height of some 70,000 miles in 1878; (2) in
1870 and 1871 it possessed a very complicated structure, whereas in
1878 the definite structure could be recognised only in two parts of
the inner corona; (3) in 1871 the corona was pink, whereas in 1878
it was pearly white; (4) the corona was ten times brighter in 1871
than in 1878; lastly, in 1871 the light of the corona came in part
from glowing gas, whereas in July, 1878, the light came chiefly, if
not wholly, from glowing solid or liquid matter. I must here point
out, that the evidence of change, however satisfactory in itself,
would be quite insufficient to establish the general theory that the
corona sympathises with the solar photosphere in the special manner
suggested by the recent eclipse observations. There are few practices
more unscientific, or more likely to lead to erroneous theorising, than
that of basing a general theory on a small number of observations.
In this case we have, in fact, but a single observed correspondence,
though the observations establishing it form a series. It has been
shown that so far as the special sun-spot period from the minimum of
1867 to the minimum of 1878 is concerned, there has been a certain
correspondence between the aspect of the corona and the state of
the sun's surface, with regard to spots. To assume from that single
correspondence that the corona and the sun-spots are related in the
same way, would be hazardous in the extreme. We may indeed find, when
we consider other matters, that the probability of a general relation
of this sort existing is so great antecedently, that but slight direct
evidence would be required to establish the existence of the relation.
But it must be remembered that before the eclipse of 1878 was observed,
with the special result I have noticed, few were bold enough to assert
the probable existence of any such relationship; and certainly no one
asserted that the probability was very strong. I believe, indeed, that
no one spoke more definitely in favour of the theory that the corona
probably sympathises with the sun-spots than I did myself before the
recent eclipse; but certainly I should not then have been willing to
say that I considered the evidence very strong.

We must then look for evidence of a more satisfactory kind.

Now, although during the two centuries preceding the invention of the
spectroscope and the initiation of the solar physical researches now in
progress, observations of eclipses were not very carefully conducted,
yet we have some records of the appearance of the cor