APRIL 11, 1907 | 
NATURE 
istic determinant is of a very high order in all but 
the simplest possible cases, and certainly the purpose 
of the investigation, that of judging the unknown 
from the known, is best served by keeping the mathe- 
matics as simple as possible. Even when this is done 
the author obtains theoretical confirmation of the 
known results regarding the spectra of metallic 
haloid salts (Lecture 14, § 1), Lockyer’s long and 
short lines, and observations on the dissociation of 
the elements in the solar protuberances (Lecture 1, 
§ 7, and Lecture xiv., § 6), Kayser and Runge’s 
series of spectral lines, and the phenomena of sur- 
face colours (‘‘ Schillerfarben ’’), under which head- 
ing the colours of butterfly scales are discussed at 
some length, this application being illustrated by an 
excellent photograph of the scales of one of the 
““blues,’? in which the dimensions of the pigment 
granules are equal to the wave-length of blue light. 
This section deals, then, with the electromagnetic 
theory of spectroscopy of which Lecture 14 forms a 
general summary. In the fourth and last section 
many of the same results are established in a different 
way, by what the author describes as the electro- 
static theory. This theory is based on the study of 
moving charges, and regards the molecule built up 
of electrified moving particles. It is, in fact, the 
electron theory, and the first lecture contains a proof 
that in the cases considered the electromagnetic 
forces are negligible compared with the electrostatic 
ones. The succeeding chapters deal with Dr. 
Stoney’s theory of double lines, J. J. Thomson’s 
models of atoms, and conditions of stability with 
special reference to the periodic law. The last lecture 
(Lecture 20) is a summary of the electrostatic theory, 
and contains explanations of the phenomena referred 
to above, based on this theory. 
In summing up, Dr. Garbasso expresses the 
opinion that the electromagnetic and the electro- 
static theories, and in some cases even mechanical 
models, are equally competent to account for observed 
phenomena. The electrostatic method he considers 
to be the most complete, but the electromagnetic 
method possesses considerable advantages for teach- 
ing purposes; it possesses a peculiar heuristic value, 
and opens up the possibility of reproducing the 
electrical oscillations artificially. 
The book makes no claims to being a text-book, or 
in any way a complete account of all that might be 
said on the subject. It contains, no doubt, many 
proofs that are open to criticism, but experience has 
shown that objections are very generally raised years 
after a book has been written, and very often on 
work which has been accepted unchallenged by a 
large number of readers. The main points we have 
now to consider are whether the author has stated 
his case well and carefully, whether the book is calcu- 
lated materially to help us in unravelling the many 
curious puzzles revealed by the spectroscope, and 
whether the methods adopted are the best suited to 
the objects in view, and on each of these points we 
pronounce judgment in the affirmative. 
Goibiew: 
NO. 1954, VOL. 75] 
5) 
ORIGIN OF THE ENGLISH NATION. 
The Origin of the English Nation. By H. Munro 
Chadwick. Pp. viii+352. (Cambridge: The Uni- 
versity Press, 1907.) Price 7s. 6d. net. 
HE title of this work really conveys a more 
accurate suggestion of its scope than the first 
sentence of the preface, which describes it as ‘an 
account of the early history of the English nation.’” 
There was certainly room for such a work, in which 
all the available evidence should be carefully con- 
sidered, and Mr. Chadwick has done this with the 
greatest minuteness. In fact, his book suffers to 
some extent from over-minute discussion of questions 
which have at best a very faint bearing upon the 
main subject of his inquiry. This is especially the 
case with the later chapters in the volume, such as 
that on the ‘‘ Cult of Nerthus.”’ 
Another general criticism which might be made is 
that Mr. Chadwick is rather too much given to the 
common, but very unsatisfactory, process of drawing 
a strong conclusion from a series of very weak 
premises. Unfortunately, much of the evidence re- 
lating to the Germanic conquerors of England during 
the time before the invasion is so fragmentary and 
contradictory that hypotheses can hardly be avoided. 
It is therefore the more necessary that they should 
be used as sparingly as possible, otherwise they are 
apt to obscure the recorded facts. In particular, it 
is of little service in the end to set modern supposi- 
tion against ancient assertion; the former is at least 
as likely to be wrong as the latter, even when it 
appears to reconcile contradictions. The author, for 
example, seeks to cast doubt upon the express state- 
ment of Bede that the invaders came from three 
nations, the Saxons, Angles, and Jutes. On various 
erounds, such as similarity of language and customs, 
he comes to the conclusion that there is not sufficient 
evidence for separating the Saxons from the Angles, 
and that the invaders ‘‘ belonged not to three but to 
two distinct nationalities.” 
That the distinction cannot be clearly perceived 
now does not prove very much; it may have been 
clear enough to themselves and to Bede. It may even 
to some extent have become obscured through the 
migration to a new country, just as national differ- 
ences soon tend to disappear in modern colonies. 
Or the difficulties raised by Mr. Chadwick may 
simply lie in the meaning to be attached to “ nation ”” 
or ‘‘people.”” In Scandinavia of the tenth century 
we find four very distinct peoples who did not differ 
from each other in any essential respect. It is no 
argument against the reality of the Saxon element 
that Englisc and Angelcynn became the usual desig- 
nation of the language and the people. Where no 
great difference was felt, the convenience of a 
common name would soon be obvious. The use of 
national names is not stable enough to be valid 
evidence in doubtful cases. The lowland inhabitants 
of Scotland in the fifteenth century called themselves 
Scots and their- language English; and Snorri 
| Sturluson evidently saw nothing contradictory in: 
