FEBRUARY 18, 1904] 
NATURE 
369 
which it has imposed upon itself. However much we may 
marvel, we must allow that this is a fact of experience, and 
as inductive science is founded on all the facts that can be 
obtained, the spontaneous movement of living protoplasm 
can»no more be omitted than the absence of initiative in 
non-living matter. So that, although we cannot explain 
how mind influences protoplasm, we must acknowledge that 
it does do so. Wariations may depend upon the amount of 
stimulus received by the mother cell, and they may be de- 
veloped automatically by selection, but neither selection nor 
stimulus can originate new processes or new structures. 
It is impossible to suppose that the external physical 
agencies, when they act upon protoplasm, antagonise their 
actions by forming chemical or physical combinations, for 
this is so different from what happens with dead matter. 
Dead protoplasm can no longer resist the attacks of other 
organisms, and it is only by undergoing the process of 
assimilation that it can be revivified. If there is any truth 
in Mr. Herbert Spencer’s definition of our conception of 
life as the continuous adjustment of internal to external 
relations, it follows that living protoplasm must be free 
to adjust itself. But whether these adjustments were 
intelligent and purposive or whether they were due to 
haphazard gropings after change is a separate problem 
which still requires solution. All that we can say at pre- 
sent is that while dead matter is subject altogether to fixed 
laws, living protoplasm is, to a certain extent, free to act. 
To it has been given the power of adaptation or antagonism 
to the physical laws which the rest of nature obeys 
implicitly. 1 
a constant war has been waged between dead and living 
matter, and mind has won, the result 
evolution. Chemical affinity has been taken advantage of 
by mind to protect itself from enemies. Physical energy 
has been used to break down chemical affinity, and then 
mind has been able to lay up a store of potential energy. 
But it has overcome the physicochemical laws only by obey- 
ing them, and this has given rise to the illusion that it is not 
free but subject to fixed law, like dead matter. This, how- 
ever, cannot be the case. At first mind was free to act, but 
constant repetition of the same experiences made it an 
apparent slave to the physical forces, although when atten- 
tion. was occasionally called into action by new external 
irritants it again reasserted itself. But this was followed 
by relapse. The cooperation and concentration of nervous 
matter, however, still went on until, in the brain-cortex, 
attention developed into consciousness, and in the large 
cerebrum of man, mind has once more passed into its 
original free state. It is this form of volition that we call 
free-will. 
Such I believe to be the full scope of Prof. Hering’s 
theory. I must confess that I have gone beyond his 
address, and I do not know that he would agree to all 
that I have said. But it is evident that we must either 
assume a freely acting mind as the mainspring of organic 
development, or we must try to explain it on a purely 
mechanical basis, a task which appears to me to be quite 
hopeless. F. W. Hutton. 
Canterbury Museum, Christchurch, New Zealand. 
Curious Shadow Effects. 
I ruink that the following is probably the explanation of 
the phenomenon referred to in Nature of February 4—the 
seeing of more shadows than your own. 
A and B are neighbouring observers; their shadows make 
dark tunnels in the illuminated mist. 
Usually, the eye cannot penetrate far, and if A is to see 
his neighbour’s shadow he has to look across it, as along 
ACD, and the layer CD is too thin to be noticeable. Or, if 
he can see further, as along AEF, the glare of the illumin- 
ated mist between A and E may prevent him from noticing 
the thicker dark layer EF. He sees his own shadow because 
he looks more or less along it. But under suitable con- 
ditions his eye may be able to penetrate so far that he can 
see the thicker layer EF of his neighbour’s shadow, while 
yet there is not much glare near at hand, i.e. in the part 
AE, to dazzle him; the mist in this region may be very 
thin. [The diagram does not represent clearly the way in 
which the shadows “tail off’? and vanish at a certain 
NO. 1790, VOL. 69] 
distance owing to the finite angular magnitude of the 
sun.] 
If the angle GAE be not too great, A will see B’s shadow 
within his own halo. 
This halo I have always taken to be the ordinary rain- 
bow. It may look small, but the true criterion is its angular 
This would not, however, explain the oval bow 
W. LaRDEN. 
magnitude. 
spoken of in Nature, January 28. 
Devonport, February 5- 
It is obvious that the bow seen by Mr. Warner and de- 
scribed in Nature of January 28 (p. 296) was the ‘‘ Ulloa’s 
ring,’’ the ‘‘ Nebelbild’’ or * Brockengespenst ’’ of the 
Germans, fully explained by Fraunhofer. The oval form 
is a necessary consequence of our seeing the sky as a de- 
pressed vault or segment of a hollow sphere, as I have 
demonstrated it in my ‘‘ Meteorologische Optik,’ I. 
Abschnitt, p. 29 ff.; see especially p. 33, Fig 5. 
I beg to answer also Mr. John A. Harvie Brown’s ques- 
| tion on shadows in the ‘‘ Brocken,”’ asked in your issue of 
Ever since living matter appeared on the earth | 
being biological | 
February 4. He says :—‘* How was it that more than one 
image was visible to each of our party? » Mr. Harvie 
Brown states that ‘‘ not one of us saw more than one 
set of concentric rainbow bands or circles.’? The answer 
seems to be simple. The shadows are objective, and there- 
fore visible to everyone; the coloured circles are only sub- 
jective, and consequently one person sees only one set of 
rings. I know that in text-books cne reads the statement, 
‘“ the observer of a ‘ Brocken’ cannot see his companion’s 
shadow,”’ as, for example, in Miiller’s “‘ Kosmische Physik ”” 
(even in the edition of 1894), but this is evidently erroneous. 
Wien, Hohe Warte. J. M. PERNTER. 
Tue staff of the Ben Nevis Observatory have had frequent 
opportunities of observing the coloured shadows formed 
round shadows thrown on mist or fog-banks; notes de- 
scriptive of these ‘‘ glories,” as we termed them, with 
measurements of their diameter, will be found in the ex- 
| tracts from the log-book printed with the other Ben Nevis 
observations (see Transactions Royal Society Edinburgh, 
vols. xxxiv. and xlii.). In each ring of these glories the 
red of the spectrum colours was outside and the blue inside, 
as in the primary rainbow, and as many as five successive 
rings of colours have been observed. 
The outside diameter of the largest ring never exceeded 
12°, and was more usually about half that amount. Glories 
are thus of the same order of size as the corone frequently 
seen round the sun or moon, and are distinctly smaller than 
halos, the ordinary halo having a diameter of about 44° 
(radius 22°), while rainbows and fog-bows are, of course, 
larger still. 
In respect to Mr. Warner’s letter, I may say that no oval- 
shaped glories have been seen on Ben Nevis, but other 
observers have described them, and a possible explanation 
may be that a circular ring is formed on a surface at right 
angles to the sun’s rays, but the observer assumes that the 
ring is formed on a vertical surface, and therefore it appears 
oval to him. However, the low angle of the sun’s rays at 
Christmas time does not differ sufficiently from the hori- 
zontal to cause in this way the elongated oval shown in 
Mr. Warner’s sketch; there must be other factors to 
consider. 
With regard to the shadows of other persons, our ex- 
perience on Ben Nevis was that if the fog-bank was a con- 
siderable distance away, the shadows of others could be seen 
just as on a wall; but if the fog was close to the observers, 
the only shadow seen resembling a human figure was one’s 
own. Sometimes, however, when a thin fog was close to us 
on one side, and bright sunshine on the other, I have seen 
the shadow of a man standing 10 or 20 yards away as a dim 
dark streak running back into the fog. The shadow, in 
fact, was not formed on any definite surface, but was a 
