Nov. 24, 1870] 
NATURE 
67 

a much larger quantity. Here again we may observe the in- 
stance Mr. Bennett quotes, the mimicry of Zeffa/is to Jthomia. 
Leptalis is normally a white insect, and as such, would be more 
liable to attacks from its persecutors, as shown by Mr. Wallace, 
while any variation which gave colour to the wing would make 
the insect less conspicuous, and being useful to it, would be pre- 
served. 
That we are quite ignorant of the laws regulating variation is 
quite true, and that when we do understand them it will throw 
much light on these questions is undoubted, and that we may 
probably find in them some additional explanation for many of 
the facts now accounted for by Natural Selection ; and Mr. Ben- 
nett does good service in the cause of truth in reminding us of 
what still has to be done, S. N, CARVALHO, JR. 
London, Novy. 17 

Four years ago I advanced the opinion that Natural Selection 
is insufficient to explain the ‘‘ Origin of Species,” and that, rather, 
the origin of the variations of which Natural Selection is said to 
avail itself must be looked to for this purpose. I may perhaps, 
therefore, be allowed to say a few words in examination of Mr. 
Wallace’s explanation of this point in last week’s NATURE. 
One of the objects of Mr. Darwin has been to show that the 
existence of species as an absolute entity is a mere idea of our 
minds ; that if we could at the same moment look around us in 
space, and also backwards in time, we should find the organic 
world connected together as one whole, one great mass of beings 
extremely closely allied to each other, and distinguishable only 
by an accumulation of small and perhaps scarcely appreciable 
differences. A second and closely-connected object has been to 
show that this great mass of beings has had a common origin from 
one primeval ancestor (or at most a few ancestors). These two 
points are the chief ones involved in the ‘‘ Origin of Species” 
question, @s 7¢ 7s ordinarily understood ; and if they be borne in 
mind, it will be seen that the doctrine of ‘‘ Natural Selection, or 
the Survival of the Fittest,” deals with only a small portion of 
the numerous problems involved in this great question. iam 
sure that Mr. Wallace, after having written as he has done about 
man, that in his case other influences than this survival of the 
fittest have been at work, may reasonably allow importance to 
other powers than Natural Selection in the case of other organic 
beings. 
If Mr. Darwin’s book had been entitled ‘‘ The Influence of 
Natural Selection on the Formation of Species,” some miscon- 
ceptions might, perhaps, have been avoided. Its present title 
undoubtedly tends to conyey the idea that Natural Selection is 
per se the Origin of Species. I believe Mr. Darwin, however, 
holds no such idea. 
The picture above alluded to, of a complicated mass of beings 
connected together by innumerable gradations, is so different from 
what we find existing around us, that one of the first questions 
suggested by it is, where are the connecting links? This first 
question has never yet been answered to any extent, or with any- 
thing like adequacy, The links produced are but few, and not 
sufficient to bear the great weight attached to them. For at no 
period of the geological record do we find any traces of the 
general and intimate connection of beings with one another that 
Mr. Darwin's views would lead us to look for, The creatures 
composing the organic world at any one given moment were, so 
far as the evidence of geology goes, separated from one another 
by lines of demarcation of similar value to those existing among 
animals now, 
What is wanted to explain the phenomena of various limited 
and defined species arising from one common ancestor is, then, 
first, a law, or group of laws, to throw light on the origin of 
yariation and dispersion ; and, second, another law or laws to 
explain the limitation and separation of the varieties so produced. 
It is quite out of the question to suppose that the theory of 
Natural Selection does all this. Those, however, who have 
studied Mr, Spencer’s work will be well aware that his theory of 
evolution may be applied to deal with the question in this its 
more extended light. And I believe that those who wish well 
for the survival of Natural Selection will do well to insist on its 
only being considered in connection with a more extensive 
doctrine of evolution, This is where I think Mr. Wallace errs 
in his advocacy. 
I will not here allude to the question of mimicry more than to 
say, that Mr. Wallace has never answered, but rather avoided, 
the chief difficulties I have advanced against it; and that his 
theories on the subject are undoubtedly open to the objection 



that he insists on seeing all the phenomena from the point of 
view of a natural selectionist, and nothing more. As Mr. Wallace 
has, however, already discovered that Natural Selection, though 
applicable to man, is not sufficient, unsupplemented, to account 
for him, we may hope that he will yet see this with regard to the 
rest of the organic world. D. SHARP 
Thornhill, Dumfriesshire 

The Chromosphere 
WHILST mapping down, in preparation for the coming eclipse, 
all the bright lines that have so far been observed and accurately 
measured in the chromosphere or solar prominences, I was struck 
with the absence of a faint yellow line, which I have myself 
several times observed whilst examining the contour of the sun’s 
disc. This line is probably identical with Angstrom’s absorp- 
tion line 58830 (spectre normal du soleil), D" lying almost mid- 
way between D’ and the line in question. There is no danger 
of mistaking it for the bright yellow line seen in every solar pro- 
minence, and lying near Angstrom 5865"1, since the two yellow 
lines were seen on each occasion at the same time on the more 
refrangible side of D”. 
I suppose the D'’, mentioned in a late communication from 
Dr. Young, to be identical with the bright yellow line, for it is 
most improbable that he could have failed either to see or to 
record the bright line whilst mentioning the faint one, since the 
latter, as far at least as I have observed, is never visible unless 
in company with the former. 
The only observation that I can at all identify with my own is 
that mentioned in NATURE, December 16, 1869, where Mr. 
Lockyer, speaking of the absorption line, which corresponds to 
the orange line of the chromosphere, says that Padre Secchi’s 
bright line is less refrangible. 
Stonyhurst Observatory S. J. PERRY 
From London to Catania 
A FEW practical details as to the best way of getting to Sicily, 
the accommodation to be found there, &c., may be of use to 
many readers of NATURE who are thinking of going there next 
month. 
We have first the sea passages from London, Southampton, or 
Liverpool, to Messina or Malta, of which if any be chosen 
it will probably be that from Southampton to Malta by the 
P. and O. steamers, which start every Saturday at 2 P.M., 
and are nine days on the voyage. (Fares 20/. and 10/7.) From 
Malta there are steamers twice a week to Messina; they touch 
at Catania when the weather permits them to enter the small 
harbour, otherwise they go on to Messina, so that passengers 
for Catania must in that case avail themselves of the railway. 
Few probably will wish to go the whole way by sea, the land 
route therefore by which the Indian mails are now sent will be 
taken; viz., over the Brenner Pass. The night mails leave 
Charing Cross at 8.45 p.M., Cannon Street at 8.50 P.M., Victoria 
and Ludgate Hill at 8.30 p.M., and arrive in Dover in time for 
the Calais and Ostend boats; the line from Calais to Brussels 
may not be practicable, and so the longer passage to Ostend 
may be preferred ; by going straight on one ought to arrive at 
Cologne at 4 P.M. the next day (if one goes by Calais one has 
three hours’ rest at Brussels). The day service train, first and 
second-class, leaves all the stations at 7.40 A.M., and one should 
arrive at Cologne via Ostend at 10.55 P.M. (va Calais at 
4.50 A.M. next day.) From Verviers to Cologne there are only 
first-class carriages in this train, The fares to Cologne by Ostend 
are 3/. 8s. 1od. first, and 2/, gs. 5a. second-class, by Calais they 
are 3s. or 45. more. 
Those who like to go from London to Ostend or to Antwerp 
direct can leave St. Katherine’s Wharf by steamer on Sunday, 
Tuesday, or Thursday mornings for Antwerp, or on Wednesday 
or Saturday mornings for Ostend, and proceed by rail to Brus- 
sels, the fares from London to Brussels being 3os. first and 
22s, 3d. second class, via Antwerp ; 26s. 8d. first and 2os. 10d. 
second class, via Ostend. The fare from Brussels to Cologne is 
about 25 francs first and 18 francs second class by the ordinary 
trains ; express about three francs more. 
The way then is by Coblentz, Mayence, Darmstadt, and 
Aschaffenburg to Munich. By leaving Cologne by the 6 A.M. 
express, one ought to get to Munich at 9.10 P.M. In times 
when through-tickets are granted the fare by Ostend and Cologne 
to Munich is 6/ 7s, 3d. om London (first class), and 54 10s, 
