April 7, 1870] 
NATORE 
581 
branches of trees, which cannot possibly be the natural 
method. For several centuries the common swallow 
has disported itself in our crowded cities, and with its 
friendly masonry attached itself to our houses. The 
chimney swallow, still more familiar and audacious, 
often builds in the smoky shafts of our domiciles, or 
even in the noisiest factories, undisturbed by the din or 
the fires or the movement around them. Such habits must 
form a strong contrast with those of their predecessors in 
times long gone by. When we ourselves wandered un- 
tutored savages in the prehistoric times, or when still 
later we constructed Jacustrine towns, or megalithic 
monuments, the habits of the birds can scarcely have been 
identical with those of to-day, for such human edifices 
afforded little security or shade. They must then have 
built amongst rocks. Nearly the same remarks apply to 
the storks, which have not remained stationary, but have 
preferred to their less commodious dwellings those offered 
to them by man. These changes in the industry or the 
manners of birds are perhaps even more rapid than we 
might at first sight suppose ; and M. Pouchet’s observa- 
tions have demonstrated to him that notable improve- 
ments have been adopted by swallows in their modifica- 
tion during the first half of the present century. Having 
directed a number to be collected for the purpose of 
having drawings made from them, M. Pouchet was 
astonished to find that they did not resemble those he had 
collected some forty years ago, and which were still pre- 
served in the museum of Rouen. ‘The present generation 
of swallows have notably improved on the architecture of 
their forefathers, amongst those still building in the 
arches and against the pillars of the churches. Some, 
however, still adhere to the old methods, or such nests 
may possibly have been old ones which have undergone 
reconstruction. In the streets, on the other hand, all the 
nests appeared to be constructed on the new method. 
And now for the differences observed. The old nests 
show, and all ancient writers as Vicillot, Montbrillard, 
Rennie, Deglaud, &c., describe the nest of the house- 
swallow as globular, or as forming a segment of a spheroid 
with a very small rounded opening, scarcely permitting 
the ingress and egress of the couple that inhabit it. The 
new nests, on the contrary, have the form of the quarter 
of a hollow semi-oval (le quart d’un demi-ovoide creux), 
with very elongated poles, and the three sectional sur- 
faces of which adhere to the walls of edifices throughout 
their whole extent, with the exception of the upper one, 
where the orifice of the nest is situated ; and this is no 
longer a round hole, but a very long transverse fissure 
formed below by an excavation of the border of the 
section, and above by the wall of the building to which 
the nest is attached. This opening has a length of nine 
or ten centimetres and a height of two centims. M. 
Pouchet considers this new form affords more room for 
the inmates and especially for the young which are not 
so crowded, whilst they can put out their heads for a 
mouthful of fresh air, and their presence does not inter- 
fere with the entrance and exit of the parents. Lastly, 
the new form protects the inhabitants of the nest better 
than the old one, from rain, cold, and foreign enemies. 
THE ROTUNDITY OF THE EARTH 
RECENT number of the /ve/d contains an account of 
a very amusing investigation which has been recently 
conducted on the Bedford Level to settle the question 
whether the earth is a globe or not! It appears that 
a Mr. Hampden threw out a challenge by which he 
offered to pay, 500/. to anyone who would prove the 
rotundity, which challenge has been taken up by Mr. 
A. R. Wallace, who has lodged a similar sum with the 
Editor of the Fze/d. To test this point, six miles of 
the Bedford Level were used, three signals, each 
13 feet 4 inches above the water level, being put up 
three miles apart. Mr. Wallace asserted that if he were 
correct the central signal would appear elevated about 
5 feet above the line joining the other two; Mr. Hampden 
holding, of course, that they would all be in the same 
straight line. It is needless to say what the result was, 
but we now come to a part of the story which is not 
so amusing, and here we quote from the #7e/d :-— 
Both Mr. Hampden and Mr. Carpenter assented to the 
details of this experiment in our presence as conclusive, although 
we regret to say that Mr. Carpenter alleged his opinion was 
founded upon theory alone, and that it had never, as far as 
he knew, been tried. Now, the fact really is, that in a little 
treatise published by ‘‘ Parallax,” and which we have now in 
our possession, with Mr. Carpenter’s name on the title-page, 
in his own handwriting, an experiment similar in its nature is 
described as having been made on the very same piece of water 
as that on which we were then occupied, with a result exactly 
the reverse of that which recently occurred. Mr. Carpenter 
was, in fact, engaged to decide a disputed question of which 
he and his principal professed to be practically ignorant, 
although it was in print on the authority of the head of their 
sect that it had already been tried in the same locality ; and 
this must have been then known to Mr. Carpenter, and has 
since been admitted by him in our presence. he good faith 
and perfect fairness of Mr. Carpenter were not, therefore, quite 
of the nature we then believed them to be, and we have no 
hesitation in affirming that he was a most improper person to 
be selected to act as referee in such a matter. The deception 
was, to say the least of it, ‘‘unscientific;” yet Mr. Carpenter 
and his master, “Parallax,” both profess to be ardent in the 
cause of science; and that it has recoiled upon their heads 
can cause no regret to anyone who values the truth. 
Although the diagrams of what was seen by the tele- 
scopes used at both ends, and acknowledged to be correct 
by Mr. Carpenter and Mr. Hampden, show the central 
signal more than 5 feet above the line of the two extremes, 
these gentlemen coolly claim the victory, and threaten to 
bring an action against the Editor of the /7ze/d (who was 
appointed umpire by Mr. Hampden himself) for fraudu- 
lently deciding against them. 
LETIERS LO THE EDITOR: 
[The Editor does not hold himself responsible for opinions expressed 
by his Correspondents, No notice 7s taken of anonymous 
communications. | 
On Prof. Tyndall’s Exposition of Helmholtz’s Theory 
of Musical Consonance 
In Narure for March 3 you published a letter of mine, in 
which I stated that the exposition of Helmholtz’s theory of 
musical consonance given in Prof. Tyndall’s lectures on Sound 
was both ‘‘ radically different from the original, and erroneous.” 
I supported my assertion by a series of arguments which, both to 
myself and to other competently informed persons, appeared 
conclusive. 
Prof. Tyndall has taken no notice, public or private, of my 
letter, although he has since its publication written in your 
columns on another subject. 
Your readers, as well as myself, are surely justified in calling on 
Prof. Tyndall either to rebut my argument or admit my conclusion. 
Trinity College, Cambridge, March 29 SEDLEY TayLor 
[Prof. Tyndall’s Lectures on Sound have been translated into 
German, and the following is a verbatim copy of the “ Vorwort 
des Herausgeber ”’:— 
“Die Vorlesungen welche Herr Tyndall als Nachfolger der 
grossen Naturforscher Davy und Faraday in dem Winter- 
monaten yor den gebildesten Kreisen Londons in der Royal 
Institution iiber die verschiedenen Theile der Physik zuhalten 
pflegt, haben in England allzeitige Anerkennung gefunden. 
Herr Tyndall besitzt in ungewohnlichem Grade die Gabe, 
durch die gliickliche Vereinigung einer eben so klaren wie ele- 
ganten Darstellung, mit vortrefflich ersonnenen und schlagen- 
den Versuchen selbst die schwierigeren Lehren der Physik dem 
gebildeten Publikum zuganglich zu machen. Eine Herausgabe 
seiner Vorlesungen in deutscher Bearbeitung diirfte desshalb auch 
bei uns nicht wenig zur Verbreitung physikalischer Kenntnisse 
in weiteren Kreisen beitragen. Die Unterzeichneten haben 
