68 NATURE 
still to persist. With a view of showing how far such 
an opinion is out of touch with the actual facts the 
authors have by repeated distillations of potassium 
got rid of the large amount of hydrogen dissolved in 
the metal, and have shown that the reduction of the 
gas is accompanied by a decrease of the photo-electric 
action. After the fourth distillation the effect was 
reduced from a current giving 850 mm. deflection to 
one too small to detect. The result amply confirms 
the view that the effect is due to the gas absorbed by 
the metal. 
THE inaugural lecture delivered by Dr. W. C. McC. 
Lewis, the successor of Prof. Donnan in the Brunner 
chair of physical chemistry at the University of Liver- 
pool, has been issued in pamphlet form, with the title, 
‘Physical Chemistry and Scientific Thought.” It is 
mainly devoted to the significance of research from the 
purely scientific aspect, especially in connection with 
some of the problems of physical chemistry. 
SincE Wohler’s first synthesis of a natural organic 
compound, the chemist has succeeded in building up 
nearly all the natural compounds from their constituent 
elements in his laboratory; indeed, the synthesis of the 
sugars, the polypeptides, the alkaloids, uric acid and 
its derivatives are some of the greatest triumphs of 
the chemist. Much of the success in this field is due 
to the genius of Emil Fischer, and though he has cele- 
brated his sixtieth birthday he shows no signs of relax- 
ing his labours, being now responsible for another 
great achievement. The importance of the nucleus in 
the cell needs no emphasis, and therefore the value of 
the recent work, more particularly of Levene and his 
collaborators, in America, on its chemical composition 
has been widely recognised. In brief, the nucleic 
acids are composed of glucosidic compounds of purine 
derivatives combined with the carbohydrates to which 
phosphoric acid is also coupled. The synthesis of such 
a glucosidic compound of sugar and purine has long 
been essayed, but it is only now brought to a success- 
ful conclusion. Once the principle of the method of 
making them has been made clear all kinds of purine 
derivatives can be coupled with the carbohydrates, and 
when phosphoric acid has been introduced into the 
molecule the complete synthesis of the nucleic acids 
will have been achieved. 
Engineering for March 13 gives an_ illustrated 
account of the new water supply scheme for New 
York. The actual water supply is derived from the 
Croton River by impounding this river and_ its 
tributaries thus providing 325 millions of gallons 
a day. The population has increased very rapidly, 
and the present consumption amounts to more than 
500 millions of gallons daily. The additional water 
supply system, now under construction, is derived 
from the various watersheds of the Catskill Moun- 
tains, from which 800 millions of gallons daily could 
be obtained. The Esopus watershed is the only one 
to be developed at present, and has necessitated the 
construction of a great dam at Olive Bridge. This 
dam consists of a central masonry portion 1000 ft. 
long, and rising to a height of 210 ft. above the bed 
of Esopus Creek. Each end of the masonry is flanked 
NO, 2306) VOL, 393] 
[MarcH 19, 1914 
by an earthen wing, which together are about 3600 ft. 
in length. The greatest thickness at the base is 
200 ft., while the top, which is traversed by a road- 
' way, is 26 ft. in width. The up- and down-stream 
faces are formed by concrete blocks of large dimen- 
sions, while the great bulk of the interior masonry is 
made of cyclopean concrete. Expansion joints are pro- 
vided, and run through the entire thickness. The 
roadway on the top of the dam will be 20 ft. higher 
than the water level, and thus will be free from the 
action of ice and waves. 
Tue directors of Messrs. Pathé Fréres have agreed 
to permit the Research Defence Society to hire any 
nine of their excellent medical and biological films for 
the modest fee of two guineas. Nine films afford 
ample illustration for a lecture of an hour’s duration, 
and as a kinema machine can be hired in most large 
towns, it should prove possible, in view of the generous 
concession of Messrs. Pathé Freres, to arrange lec- 
tures in support of the work of the Research Defence 
Society at a comparatively small cost. Further par- 
ticulars of this promising scheme for educating the 
public in the value of modern medical research can be 
obtained from the honorary secretary to the society, 
Mr. Stephen Paget, 21 Ladbroke Square, London, W. 
Messrs. LonGMANS AND Co. announce as in pre- 
paration, ‘* Principles of General Physiology,” by Prof. 
W. M. Bayliss. In the volume special attention will 
be given to reactions in colloidal systems, oxidation, 
action on surfaces, secretion, excitation, inhibition, 
nutrition, etc. Messrs. Longmans and Co, also give 
notice of a new series of monographs on_ physiology 
which will be under the editorship of Prof. E. H. 
Starling. The following volumes are in preparation :— 
‘The Involuntary Nervous System,” Dr. W. H. Gas- 
Ixell; ‘‘ The Physiology of Reflex Action,” Prof. C. S. 
Sherrington; ‘‘The Conduction of the Nervous Im- 
pulse,” Dr. K. Lucas; ‘‘The Physiological Basis of 
the Action of Drugs,’ Dr. H. H. Dale; ‘‘The Secre- 
tion of Urine,” Prof. A. R. Cushny; ‘‘The Contrac- 
tion of Voluntary Muscle,’’ Dr. W. M. Fletcher; 
‘“The Cerebral Mechanisms of Speech,” Dr. F. W. 
Mott; ‘‘The Chemical Mechanisms of Integration in 
the Animal Body,” Prof. E. H. Starling. 
OUR ASTRONOMICAL COLUMN. 
ELECTRIC WAVES AND THE ComING ToTaL SOLAR 
EcLipsE.—It is hoped that the forthcoming total solar 
eclipse of August 21 will be fully utilised to study the 
effect of the propagation of electric waves, as this 
event affords an exceptional and important opportunity 
of adding to the existing knowledge of the propaga- 
tion of electric waves in sunlight and in darkness and 
across the boundaries of illuminated and’ unillumin- 
ated regions. The total eclipse track passes across 
Greenland, Norway, Sweden, Russia, and Persia to 
the mouths of the Indus; in Russia the duration of 
totality will be a little more than two minutes. A 
circular, distributed by the British Association 
committee for radio-telegraphic investigation sets 
forth details of this special kind of investigation 
and this committee would be greatly aided in the 
organisation of this piece of research if those possess- 
ing the necessary facilities and willing to make ob- 
