NATURE 
[ApRIL 1, 1897 
LETTERS TO THE EDITOR. 
(The Editor does not hold himself responsible for opinions ex- 
pressed by hes correspondents. Netther can he undertake 
to return, or to correspond with the writers of, rejected 
manuscripts intended for this or any other part of NATURE. 
No notice zs taken of anonymous communications. | 
Early Arrival of the Swift. 
A FEW minutes before six o’clock in the afternoon of March 
26, my brother, Sir Edward Newton, saw, from the cliff near 
the high lighthouse at Lowestoft, what, at the first glance, looked 
like a Swallow, flying over the trees in the garden of the house 
known to many as that occupied more than thirty years ago by 
the late Dr. Whewell. As the bird turned and gave us a better 
view of it, we perceived it to be a Swift. Crossing the foot- 
bridge and getting to the edge of the Park overlooking the 
garden, we watched it pass backwards and forwards for about a 
couple of minutes, when it flew away to the northward, and, 
though we waited for some little while, it did not reappear. I 
may add that we were favourably placed as regards light, the 
sun being behind us. I do not recollect any record of the 
occurrence of the Swift in England so early as this by some 
weeks, and it would be interesting to kriow if the bird should 
have been observed elsewhere. ALFRED NEWTON. 
March 27, 
Red Dust of Doubtful Origin. 
On Tuesday morning, March 22, I noticed on the glass of 
our greenhouses, and on many of the shrubs, a sort of red dust. 
On making inquiries I found the same thing existed about two 
miles off, due west. I collected some, and, by the kindness of one 
of the directors of Messrs. Brunner, Mond, and Co., it was 
examined in the laboratory connected with their works. To-day 
I got the report, which is as follows :— 
“‘The dust, under high magnification, shows minute frag- 
ments of clayey matter mixed with quartz. Organic matter 
such as pollen grains are absent. The particles are about 
00001 millimetres in diameter, many of them less. 
“©The chemical examination shows clay mixed with a little 
carbonate of lime and a fair amount of fine sand. The reddish 
colour is due to oxide of iron.” 
We are surrounded by grass; the soil is a clayey loam without 
oxide of iron or quartz. 
Could any of your readers suggest where the dust can have 
come from ? : J. M. YATES. 
Davenham, Cheshire. 
Experiment on Interference. 
I HAVE successfully performed the following experiment on 
interference :— 
To the prongs of an electrically-driven fork are fastened the 
ends A and B ofan elastic string ; at the middle point, c, of this 
string another string, ¢ D, is fastened. is held ina clip, and 
the whole stretched. By properly adjusting the lengths and 
A 
Coen eer, 
B 
tension, A C and & c will vibrate in unison, while c D remains 
motionless; but if A c or BC be damped, c p immediately 
vibrates. 
This is a very pretty experiment when projected, and by flash- 
ing the light on it is easily demonstrated that A C and B € are 
always in opposite phases. JOHN WYLIE. 
ror University-street, Belfast, March 8. a 
D 
The Additional Colouring Matter of ‘‘ Fucus 
vesiculosus.” 
_ I do not know whether the following is likely to be of any 
interest to your readers. 
Having prepared a solution of the brown additional colouring 
matter of the common Bladder wrack, I placed it in the line of 
a beam of sunlight that had passed through a prism, with the result 
that the violet indigo and blue rays were entirely intercepted, 
whilst the yellow orange and red rays were practically unaffected. 
I repeated this test with vessels that, owing to their flatter form, 
presented varying quantities of the solution, and in one in which 
the rays had only to pass through about a quarter of an inch of 
NO. 1431, VOL. 55 | 
the liquid the green rays were slightly visible, but neither the 
blue nor the violet. To make sure that the vessels had nothing 
to do with the result, I filled them with plain water and passed 
the beam through them. 
Is it justifiable to conclude from this that the action of this 
additional colouring matter is to protect the chlorophyll from 
the relative increase of the blue rays, and 7zo/ to heighten the 
effect, save indirectly, of the others? 
Could any of your readers refer me to any papers upon the 
chemical nature of this additional colouring matter, &c. ? 
CLARENCE WATERER. 
* Ingleside, Northdown Road, Margate, March 8. 
Chinese Yeast. 
IN answer to Mr, C. E. Stromeyer’s query in NATURE, 
March 18, p. 463. 
An account of L&vzzve chinozse, with details on the manner in 
which it is prepared, and on the moulds, yeasts, and bacteria 
it contains, is given by Calmette in the Aznales de Plnst. 
Pasteur, t. vi., 1892, p. 604. A lengthy review of Calmette’s 
paper appeared in Centralblatt fiir Bakterologie, vol. xiii., 
1893, p. 273: IraLo GIGLIOLI. 
Agricult. Chem. Laboratory, Portici, near Naples. 
The Electric Eel. 
ON a recent expedition to the N. W. district of British Guiana, 
I was able to secure a specimen of the electric eel, which I 
believe to be the largest on record. The fish measured 7 feet 
2 inches in length. It was caught with hook and line ina very 
shallow and unfrequented branch of the Waini River. Theskin 
is now in the local museum. J. J. QUELCH. 
British Guiana Museum, March 3. 
The Utility of Specific Characters. 
I Ave followed the discussion on this subject with great 
interest ; and though I am at such a distance that my thoughts 
may come a little late, I wish to call attention to a few points. 
In Nature for October 22, 1896, p. 605, mention is made of 
a discussion on Neo-Lamarckism at the British Association. 
In opening the discussion, Prof. Lloyd Morgan referred to the 
importance of noting the bearing of certain cases that may be 
considered as crucial, or as nearly crucial as any that we are at 
present able to obtain, on the process by which specific instincts. 
are built up. As illustrating this class of cases, he refers to the 
drinking instinct in newly-hatched chickens, where the instinc- 
tive response begins at the point where the teaching of the 
parent bird would naturally be inadequate. 
The question I wish to raise is, whether such observations as 
this can do more than justify the conclusion that life-saving 
instincts are strengthened and established by natural selection. 
Are they sufficient to show that all permanently inheritable 
specific characters are wholly due to natural selection, or even 
that natural selection is always one of the factors by which any 
and every permanent character has been built up? It seems to 
me that there are large classes of facts, some of which may be 
found in almost every species we examine, which throw doubt 
upon there being any such inseparable connection between. 
natural selection and the inheritance of characters. 
The majority of the human species inherit right-handedness. 
Does this prove that right-handedness is better for the race than. 
left-handedness? The shells of most molluscs are coiled in a « 
way that is called dextral; but some groups of species are as 
constantly sinistral as most groups are dextral ; and of the dextral 
groups there are certain species that are persistently sinistral ;. 
others that are nearly equally divided between dextral and 
sinistral forms. Is it necessary to believe that for each species 
that is usually either dextral or sinistral, there is some vital 
necessity that would exterminate, or even diminish, the species 
if the character was reversed? A similar class of cases is found 
amongst the different species of flat-fish. One species persistently 
lies on the right side, another on the left, and I think it is Mr. 
Cunningham who has told the readers of NarureE that there 
are some species in which both forms may occur. In twining 
plants similar persistence is observed in the direction in which 
the vine encompasses the support. In each of these classes of 
cases I am unable to conceive of any advantage gained by the 
species that would not be equally gained, if the character under 
discussion was reversed. If the adaptation to the environment 
of a flat-fish that now lies upon the right side would be equally 
