26 NATURE 
ing the application of thermodynamics to electro- 
chemistry, and the “Nernst Theorem.” In 
part ii. the author discusses photo-chemistry, 
the theory of radiation, and the application of the 
theory of Quanta to the problems of photo- 
chemistry, radiation, and the kinetic theory of 
matter. These highly important aspects of what 
one might term the “newer physical chemistry” 
are dealt with in a very simple and clear fashion, 
and this part of the book will be exceedingly valu- 
able to students of chemistry. 
During the last decade the scope and import- 
ance of physical chemistry have become enor- 
mously increased. To write within moderate 
compass a good text-book on the subject has 
become a task of rapidly increasing difficulty. 
Nevertheless Prof. Lewis has achieved this task 
with an admirable success. One might say of 
him, “Jeunesse savait, jeunesse pouvait.” 
F. G. Donnan. 
THE FLORA OF ALL AFRICA. 
The Flowering Plants of Africa: An Analytical 
Key to the Genera of African Phanerogams. 
By F. Thonner. Pp. xvi+647. (London: 
Dulau and Co., Ltd., 1915.) Price 15s. net. 
HE work under notice is a translation of the 
author’s “Die Blitenpflanzen  Afrikas,” 
which appeared in 1908. The preface is dated 
Vienna, Austria, 1913, and the work was issued by 
the Burleigh Press, Bristol, in 1915. Dr. A. B. 
Rendle revised the translation, which includes 
“diagnostic characters of the genera, the approx- 
imate number of African species described up to 
the end of the year 1910; their geographical dis- 
tribution, their uses, and their more important 
synonyms.” So far as tested, it is up to the date 
named; but six years’ additions are very con- 
siderable, Kew alone having published at least 
300 new species, leaving new genera out of the 
question. But comprehensive compilations neces- 
sitate supplements if they are brought as nearly 
as possible up to date of publication; and Thonner 
gives six pages of corrections and additional 
genera, chiefly from the years 1911 and 1912. 
The descriptive part of the work occupies about 
550 pages, and the general distribution of the 
genera enumerated is set forth in a_ statistical 
table. It should be understood that only families 
and genera are described, and the classification is 
Englerian. The area embraced includes all the 
African islands, from the Azores to Tristan da 
Cunha, and Secotra, the Mascarenes, and Mada- 
gascar to Kerguelen. And the geographical 
divisions of the mainland are physical rather than 
political. Thonner’s enumeration and estimates 
afford a record of 226 families of flowering plants 
indigenous in the African region, and represented 
therein by 3551 genera and 39,800 species, or say 
40,000.. His estimate for the world is 10,055 
genera, with a total of 144,500 species, and his 
figures are certainly not too high. The table also 
shows the numbers for North, Central, and South 
Africa, and the Malagasy Islands. 
NO. 2446, VOL. 98] 
[SEPTEMBER 14, 1916 
Other features of the book are: a condensed! 
bibliography, a glossary, indexes to the popular 
and botanical names, and a list of -the plates. 
and the abbreviations of authors’ names. The 
plates are excellent, and represent members of 150: 
families, and the letterpress is clear and idiomatic. — 
Wherever possible the author has chosen as dis- 
tinctive characters such as are visible to the naked 
eye in a plant in flower. First comes a key to the 
families, followed by descriptions of the same, and’ 
under each a key to its genera, including a con-- 
siderable number of introduced plants. The plan 
and scope of the work have been somewhat fully 
explained, because that seemed a more useful 
course than a technical criticism. Its full value 
can only be determined by actual use; but an ele-- 
mentary knowledge of external morphology and 
descriptive terminology would be necessary and 
sufficient to enable the student to understand the 
treatment of the subject. As a book of reference: 
only it answers many interesting questions. 
W. Bortinc Hemstey. 
CHRISTIANITY IN PARTIBUS. 
Monument in China. By Prof. 
P. Y. Saeki. Pp. x+342. (London: Society 
for Promoting Christian Knowledge, 1916.) 
Price ros. 6d. net. 
The Nestorian 
HIS volume deals with one of the most inter- 
esting romances of literature ever known. 
The story has often been told before; but it will 
bear repetition, on the chance of reaching some 
whose reading may have lain in other directions. 
The Christian religion, under the guise of what 
is now known as the Nestorian heresy, was. 
carried to China early in the seventh century A.D. 
by a mission dispatched under the auspices of 
adherents who had been for some time seeking 
in the Far East the development which was denied: 
to them in the West. Nestorius had been ap- 
pointed Patriarch of Constantinople in a.p. 428, 
but in an evil moment for himself he conceived 
the idea that all difficulties as to Christ’s birth 
would vanish if it were understood that He had 
distinct human and divine persons. 
was deposed in 431, and a few years later he 
disappeared. ; 
Nestorianism survived its founder for many 
centuries. Reaching China in the year 631, its. 
advance was so rapid that by 635 Nestorian mis- 
sionaries were allowed to settle at the capital, 
where for a couple of centuries they enjoyed 
Imperial protection and even patronage. In 781 
the Nestorian Church of the day set up a huge 
stone tablet, more than g ft. in height, more than 
3 ft. in breadth, and about a foot thick. On this 
tablet an inscription was carved, in Chinese and 
Syriac, explaining and glorifying the Christian 
religion, and celebrating the praises of the great 
and good Emperors who had permitted this teach- 
ing to take root and flourish. For flourish it un- 
mistakably did, and so it was found in the 
thirteenth century by Marco Polo. Then, during 
the fourteenth century, it faded away, leaving no: 
For this he - 
