May 13, 1915] 
NATURE 285 

called prehistoric times were skilled in  stone- 
working, as is shown by the great megalithic 
ruins at Tiahuanaca, described by Sir Clements 
Markham in his book, “‘ The Incas of Peru.”’ Since 
the building of this city, geological changes seem 
to have been in action which caused the elevation 
of the plateau and the shrinkage of the body of 
water now known as Lake Titicaca. 
These changes brought about the present con- 
ditions: a very dry atmosphere, with a small per- 
centage of oxygen and a high range of tempera- 
ture, inducing nervousness and mental instability, 
a lack of forethought and industry, an over- 
weening contempt of foreigners, and a perfervid 
patriotism. Many physiological facts indicate this 
retrogression, resulting in administrative  in- 
capacity, and neglect of regularised education. 
The poorness of the food supply, ill-cooked 
potatoes and maize-flour cakes, promotes physical 
degeneration and leads to over-indulgence in 
stimulants. The writer takes, perhaps, too gloomy 
a view of a people whom he dislikes and despises, 
but he appears to write with adequate knowledge, 
and his monograph, if his conclusions be accepted, 
furnishes a good example of the action of an 
unfavourable environment upon a race exposed to 
its influence. 
A Pilgrim’s Scrip. By R. Campbell Thompson. 
Pp. xii+345. (London: John Lane, 1914.) 
Price 12s. 6d. net. 
THESE slight, discursive sketches of the life of a 
wandering archeologist in the Nearer East are 
interesting and instructive. The studied archaism 
of the style, a trick which may have been learned 
from Mr. Doughty’s famous ‘Travels in Arabia 
Deserta,” becomes, after a time, a little mono- 
tonous, but it gives a piquant flavour to his 
accounts of eastern life and character. The writer 
is one of the school of scholarly antiquaries, 
trained by the British Museum, who, in spite of 
many hardships and the necessity of making 
scanty funds go a very long way, have done noble 
service in adding to our national collections. 
Mr. Campbell Thompson’s experience has given 
him a considerable insight into the back of the 
oriental mind,and his hints for dealing with these 
races and conducting excavations will be service- 
able to those who may follow his tracks. His 
wanderings have extended widely: Mosul, Behis- 
tun, the Sinaitic Peninsula, the Sudan, Angora, 
and Carchemish, are some of the stages. Perhaps 
the most interesting episode is his excursion, in 
company with Mr. L. W. King, to make a fresh 
copy of the famous inscription of Darius at 
Behistun, the riddle of which was solved by the 
genius of Sir H. Rawlinson. Swung from cables 
suspended over the precipice the explorers collated 
Rawlinson’s copies, which proved to be wonder- 
fully accurate, and succeeded in photographing, 
from a five-foot range, the splendid head of the 
warrior king—a fine piece of work told modestly 
and clearly. 
The book is well illustrated by photographs and, 
which is unusual in popular works of travel, is 
provided with an excellent index. 
NO. 2376, VOL. 95| 

Morale Fondée sur les Lois de la Nature. By 
M. Deshumbert. Cinquiéme et Sixieme Mille. 
Pp. tg1. (London: Watts and Co., n.d.) 
Tue Comité International de Propagande pour la 
Pratique de la Morale fondée sur les Lois de la 
Nature has representatives in eighteen countries. 
Its Bureau Central is at Dewhurst, Dunheved 
Road West, Thornton Heath, England. It issues 
a propagandist volume on the subject of a natural 
morality, written by the secretary, M. Deshumbert, 
which has been translated into eight languages. 
Much has been written on morality “according to 
nature,’ since the Stoics invented the idea, but 
this book, partly because the author understands 
both physiology and biology, has a freshness of 
appeal. ‘Good is all that contributes to the con- 
servation and increase of life .” by co-opera- 
tion and mutual aid of individuals each of: whom 
is thus aided towards complete self-realisation. 
Evil is all that diminishes life. The end of Nature 
is life and more life. 
These and connected axioms are well illustrated 
by examples of anti-natural human superstition 
and of the importance in the animal world of 
intellectual and moral qualities. The way in 
which, e.g. the tiger depends for existence upon 
observation, judgment, patience, — self-corftrol, 
decision, and perseverance, is quite a fresh object- 
lesson. A collection of practical rules of personal 
hygiene and a detailed list of physiological func- 
tions are useful, and might form the nucleus of 
a modern scheme of individual morality. Some 
quotations from J. Payot are interesting here. A 
set of parallels between the intelligence of nature 
and of man is interesting, and might be aug- 
mented. “Man in many cases is inferior to 
nature,” but this simply points the truth that man 
is part of nature. 
LERRERS» NO” RHE 2 DIOR. 
[The Editor does not hold himself responsible for 
opinions expressed by his correspondents. Neither 
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 is 
taken of anonymous communications. | 
Ultra-Violet Excitation of the D Line of Sodium. 
Ir is well known that the D line of sodium is the 
first member of a series of lines, the other members 
being in the ultra-violet region of the spectrum. It is 
known also from the investigations of R. W. Wood 
that sodium vapour at a moderate temperature illu- 
minated by D light gives rise to a secondary emission 
of D light. This secondary emission is appropriately 
called by him resonance radiation. It has been further 
investigated by Dunoyer. 
The first ultra-violet line of the series is situated 
at wave-length 3303. It is very probable for a num- 
ber of reasons that this or any other line of the 
series would give rise to resonance radiation, though 
I do not know of any experiment directly establishing 
the fact. 
A more doubtful question is whether stimulation 
by the line 3303 would give rise to D light. The 
question is not new. It has been proposed by Prof. 
Wood, and he has looked for the effect, but without 
success. The matter seemed important enough, how- 
