DECEMBER 31, 1896| 
NATURE 
201 
Attempts to obtain other similar relations in the 
spectra of gases have not so far led to any results. If 
the differences between the frequencies of the funda- 
mental and the higher members of the principal series 
are taken, we obtain numbers not far distant from the 
frequencies of the first subordinate series, but this is only 
a consequence of the facts that the value of B in Kayser’s 
_formula does not vary much, and no importance can be 
attached to these coincidences, which are only very 
approximate. A few reflections concerning Kayser and 
Runge’s equation may not be out of place here. The 
different periods of the same series have every appearance 
of having the same relation to the fundamental vibration 
as the overtones have to the fundamental of a sounding 
body. A word is much wanted to express for molecular 
vibration what corresponds to an overtone in sound. 
The term “harmonics” is sometimes used, but is not 
appropriate, as an overtone may or may not be harmonic 
to the fundamental. I suggest the expression “ over- 
period.” In a sounding body the frequency of the. over- 
tones gradually increases without limit, but the’ over- 
periods observed in the spectra of elements gradually 
approach a definite limit, which we have called the con- 
vergence frequency. We may imagine a number of 
particles in a row, and raise the question whether we 
can imagine some connection between them such that 
they should be able to vibrate in a ‘series of periods 
similar to those observed in the spectra of gases. 
If the particles are detached like those of 
Reynolds’ disconnected ,pendulums, all overperiods 
would be equal, and it does’ not seem impossible 
to imagine some connection such that for the lower over- 
periods the connecting forces regulate the frequency, 
while for the higher overperiods the frequency tends to 
become equal to that of the separate particles. Looked 
at from a different point of view we may say that, if we 
could imagine a rod having elastic properties such that 
the relation between the velocities of a wave along it and 
the wave-length is 
V=aa — bn3 
it would, if vibrating freely, give out a number of notes, 
the relative frequency of which would be the same as 
that of the luminous vibrations given out by a hydrogen 
molecule. ARTHUR SCHUSTER. 
THE EARLY LIFE OF NANSEN:} 
pats volume was compiled at a time when the early 
confidence in the success of the great Arctic effort 
had given place in Norway to a feeling of anxiety, if not 
of alarm. The translation is. now published when the 
preliminary narrative of Nansen’s triumphal procession 
across the polar area has cast his former exploits into 
the shade, and the expectancy with which the complete 
account of the expedition is awaited by the public will 
not be appeased by the book before us. It comes, in 
fact, a trifle inopportunely. To modify a wearied 
metaphor, the play of Aamz/et is cut short before the 
central scene ; the Scandinavian Prince has just begun 
to absorb attention when the curtain falls. The book 
is also heterogeneous in a high degree; no less than 
six authors are concerned in it, and the fact that all the 
varied contributions are translated by the same hand, 
robs them of some of their original freshness, although 
the translation is really done very well. Perhaps the 
unifying principle of the ill-arranged chapters may be 
found in “‘ Peer Gynt,” copious quotations from which 
are scattered over the pages. An abstract of that 
famous work would have proved no bad substitute for 
the tedious chapter on the Great Ice-Age. which, even 
1 “*Fridtiof Nansen, 1861-1893. By W. C. Brégger and Nordahl 
Rohlfsen. Translated by William Archer. Pp. x +402. (London: Long- 
mans, Green, and Co., 1896.) 
NO. 1418, VOL. 55 | 
when abridged by the translator, has little to do with 
the other subjects considered. The chapters on the out- 
fit of the /vam, her voyage to the Kara Sea, and Baron 
Toll’s adventurous sledging expedition to the New 
Siberian Islands, should have been left for the forthcoming 
work on the polar expedition, a fact which will make 
them none the less interesting to the general reader. The 
chapter devoted to an interview with Mrs. Nansen is a 
clever piece of journalism, but of doubtful taste. 
So far as the work is biographical it is welcome and 
fairly satisfactory. It is natural that the world should 
wish to know something of the personal life of the men 
who perform great achievements, and it is proper that 
this wish should be gratified. 
No one has ever met Nansen without being struck by 
his remarkable personal charm. This happened to be 
the first fact I knew about him. A friend, who had been 
spending a holiday in Norway nine years ago, told me, 
on his return, that what most impressed him there was 
the appearance and the kindness of a stranger who had 
shown him the way while lost in the tortuous lanes of 
Bergen, and who, on saying good-bye, mentioned that 
his name was Nansen. When Nansen came to this 
country after the Greenland expedition, the curious 
magnetism of, his presence at once recalled the forgotten 
remark heard two years before. A similar experience, 
occurring to many people, is frequently referred to in 
the biography. 
Nansen was not the first Arctic hero of his family, the 
record of his ancestry beginning appropriately with an 
account of old Hans Nansen, who, born in 1598, explored 
the White Sea, and spent many years in command of a 
vessel in the Iceland trade. He combined literary work 
with his navigation, and wrote a “Compendium Cosmo- 
graphicum,” wherein he treated of the heavens and the 
earth, and described Arctic routes so well that a copy 
of the book was found in use in the year 1841, in) pre- 
ference to more modern sailing directions. More im- 
mediate ancestors on both'sides were persons of strong 
character, although their interests and activity lay in 
other departments ; and the authors trace to them, with 
some skill in the application of the laws of heredity, the 
blending of poetic and esthetic feelings with the reckless 
daring and unalterable determination of Fridtiof Nansen’s 
character. ; 
Born in 1861 at Great Fréen in. West Aker, near 
Christiania, Nansen was not long in showing his love 
for adventure, carelessness of danger, and disregard of 
pain. His father, a member-of the legal profession, was 
a stern disciplinarian, but the discipline was judicious 
and directed to the development of character ; his mother 
was remarkable for her determination and practical re- 
sourcefulness ; she was, also an: enthusiastic snow-shoe 
runner, before that pastime became the common sport 
for ladies it now is. ; Vaal 4 
Nansen’s school-life is briefly traced, and his enthusiasm 
for athletic exercises and sport of every kind_ treated 
more fully and sympathetically, with extracts from his 
own early letters. Entering the Christiania University 
in 1880, he decided, after some hesitation, to take up 
zoology as his special study. Two years later he made 
his first acquaintance with the Arctic regions during a 
cruise on the Vz&éng, which, while unfortunate from the 
owner’s point of view, was full of opportunities for zoo- 
logical observations and, above all, for polar-bear hunt- 
ing on the east of Greenland. The story of this voyage 
is graphically told from the unpublished diary kept by 
Nansen. Immediately on his return to Norway, the 
curatorship of the Bergen Museum was offered to him, 
and eagerly accepted, as it afforded exceptional oppor- 
tunities for zoological research. Here Nansen was under 
the direction of Dr. Danielssen, the founder of the 
museum, a tireless worker, and a true friend. In his 
farewell letter in 1893, Nansen wrote :— 
