458 
NATURE 
[| Marcu 14, 1907 
everyone who uses the petrol-driven motor-car is at 
the mercy of the kings of oil finance, who at present 
are masters of the situation. 
Another important matter, that of electrical motor 
vehicles, is dismissed in a single chapter, although, 
01 account of the recent reductions in the cost of 
electrical energy, the prospects of this class of vehicle 
are increasingly good. 
In the chapter devoted to the consideration of the 
efficiency of transmission gear, the matter is dealt 
with in an ingenious manner, and it is probable that 
the rough-and-ready method adopted by the author 
of calculating the transmission losses is within a 
narrow percentage of being correct. The objects of 
the tourist trophy race initiated by the Automobile 
Club are clearly explained, and the cars taking part 
in the first of these races are tabulated and their 
performances usefully compared. 
Altogether, the author, in this second volume, has 
been very reasonably successful in dealing with the 
difficult task of getting together sufficient descriptive 
matter to satisfy any reasonable inquirer, and has 
made his matter as short as was possible, consider- 
ing that he has been compelled to describe a mass of 
vehicles the bulk of which resemble one another very 
closely, as most of the designers have copied the main 
features of two or three Continental models, and only 
vary in certain details or special methods of 
cheapening or facilitating manufacture. 
THE SOLAR RESEARCH UNION. 
Transactions of the International Union for Co- 
operation in Solar Research. Vol. i. (First and 
Second Conferences.) Pp. 257. (Manchester : 
University Press, 1906.) Price 7s. 6d. net. 
i a previous number of this Journal a brief sum- 
mary was given of the proceedings of this Inter- 
national Union at its second conference, held at 
Oxford in September, 1905. The volume before us 
gives a complete historical account of the union 
from its origin in 1904 up to the end of the work 
completed at the Oxford meeting, and its appear- 
ance is due to the energy of the chairman, Prof. 
Schuster, who has brought all this useful material 
under one cover. 
The subject is dealt with under seven heads. The 
first shows that the origin of this union was due 
to Prof. George E. Hale, who issued a circular letter 
to a number of men of science interested in solar 
physics. The receipt of favourable answers led him 
to approach various societies and academies, with the 
result that a meeting was arranged and held in con- 
nection with the International Congress of Science 
at the St. Louis Exhibition. 
Part ii. deals with the proceedings of the first 
conference, which took place in September, 1904, and 
is followed by part iii., which contains in extenso 
the papers submitted to the conference. They include 
introductory remarks by Prof. Hale on the import- 
ance of international cooperation in solar research, 
and valuable reports by Henry Crew, A. Peérot, 
@)BRabry, EL. 
NO. 1950, VOL. 75 | 
Kayser, and Lewis Jewell on the 
importance of establishing a new system of standard 
wave-lengths. 
In part iv. we are made acquainted with the pre- 
parations for the second conference. A portion of 
this consisted in sending out circular letters to 
members of the union and others, relative to such 
subjects as the fixing of standards of wave-length, 
measurement of the intensity of solar radiation, work 
done with the spectroheliograph, and the spectra of 
sun-spots. In response to these, numerous valuable 
replies were received, and these are all included in 
the volume. : 
At the Oxford conference some important papers 
were communicated (part vi.), among which may be 
mentioned the compensating pyrheliometer, by K. 
Angstrom. At this conference the constitution of the 
union also was discussed, and we have in this volume 
(part viii.) the text in English, French, and German 
of the constitution as finally adopted, and the resolu- 
tions, also in the three languages, concerning the 
various important questions discussed. 
An important result of the Oxford conference was 
the appointment of committees to take in hand the 
work of preparation and organisation of investi- 
gations which have not yet been collected and co- 
ordinated. 
In connection with these, the present volume con- 
tains a very valuable memoir, drawn up by Prof. 
Fowler, on the observations of the spectra of sun- 
spots in the region b to E (part vii.). This paper 
brings together in a very admirable manner the main 
features of the spectrum-analysis of sun-spots, and 
will serve as a valuable guide to those observers 
who talke up this part of solar physics. 
The next meeting of the union will take place at 
Meudon in May of the present year. There is every 
probability, therefore, that a second volume of these 
transactions will make its appearance during the next 
twelve months. 
AGRICULTURAL ANALYSIS. 
The Principles and Practice of Agricultural Analysis. 
By Dr. H. W. Wiley. Vol. i. Soils. Second 
edition, revised and enlarged. Pp. xii+636. 
(Easton, Pa.: Chemical Publishing Co.; London: 
Williams and Norgate.) Price 18s. net. 
ee WILEY’S treatise on agricultural analysis 
has long been the chief resource of every worker 
in that domain, because it contained not merely the 
particular method in vogue, but to a large degree all 
| the methods that had been proposed or were in use 
in either American or Continental laboratories, very 
often in the words of the original. This did not 
make the book easy to use by the tyro, for Dr. Wiley 
rarely attempted any criticism or recommended one 
method beyond another, but the collection was ex- 
tremely useful to the investigator, and saved him 
much labour in trying over things which had been 
tested before. The gain is particularly apparent in 
dealing with soils, the subject of the present volume, 
for the analysis of a soil is not like that of a manure, 
where there is a definite element or elements to be 
: 
