NATORE 
447 

THURSDAY, JUNE 24, ro15. 

CHEMISTRY. OF PETROLEUM. 
The Chemistry of Petroleum and its Substitutes. 
By Dr. C. K. Tinkler and Dr. F. Challenger. 
Pp.. xvi+352. (London: Crosby Lockwood 
and Son, 1915.) Price 1os. 6d. net. 
BOOK on the chemistry of petroleum, 
HN written for English students, arouses a 
special interest if only by the fact that, although 
it is largely used, the raw material is neither 
found nor refined in this country. In short, the 
industry, except as a matter of buying and selling, 
does not exist. 
The title is, however, unintentionally mislead- 
ing. Although it is called a practical handbook, 
the term does not imply any technical details of 
production, such as one finds in the volumes of 
Sir Boverton Redwood. It is concerned only with 
the chemistry of the subject—that is to say, its 
theoretical side—and such simple practical experi- 
ments and tests as can be performed in a labora- 
tory. Moreover, “the substitutes’ monopolise a 
large share of the volume. For example, the 
descriptive portion of the petroleum industry 
occupies less than one-twentieth of the total 
number of pages, and about the same amount 
of space is aecorded to the distillation of bitu- 
minous shale, of coal, and of coal-tar, and to 
the production of ethyl alcohol and wood spirit, 
whilst tests of various kinds, including the deter- 
mination of physical constants and a few simple 
organic preparations, fill up the rest of the volume. 
The book is actually a treatise on the chemistry 
and valuation of liquid fuels, and is intended to 
serve as a text-book for a part of the curriculum 
which, together with the course on petroleum 
mining, forms one of the subjects for the diploma 
or B.Sc. degree of the University of Birmingham. 
Having briefly indicated the scope and object 
of the book, we can only express our full agree- 
ment with the writer of the introduction (Sir B. 
Redwood) that, in providing a text-book for stu- 
dents who desire to become proficient in the 
chemical technology of petroleum, the authors 
properly consider that no man can become a suc- 
cessful technologist until he has fully mastered 
the underlying scientific principles of the subject. 
There is no doubt that, at the present time, 
when such large quantities of liquid fuel are used 
for motive power and where so much ignorance 
of the methods of estimating the value of these 
substances prevails, a book of this character, 
the aim of which is to teach technical methods of 
analysis, ought to, and no doubt will, command 
general interest. If we have one criticism to offer 
NO. 2382, VOL. 95 | 

it is that an attempt has been made to combine 
the study of organic chemistry with that of tech- 
nology. The whole range of organic chemistry 
is run through in the first 62 pages, followed at 
intervals by the description of a few substances 
| which the student is supposed to prepare in the 
laboratory. 
As a preparation for the future expert tech- 
nologist in so complex and so important a branch 
as the chemistry of liquid fuel, we should consider 
this wholly inadequate, and that a substantial 
course of theoretical and practical organic 
chemistry ought to precede its applications. 
Apart from this, we can cordially commend the 
volume and the excellence of the information it 
J. B.C. 
contains. 
SIGNIFICANCE OF SEXUAL 
REPRODUCTION IN PLANTS. 
The Evolution of Sex in Plants. By J. M. Coulter. 
Pp. ix+140. (Chicago: University of Chicago 
Press; London: At the Cambridge University 
Press, 1914.) Price 4s. net. 
ROF. COULTER gives a luminous sketch 
of the probable history of sexual re- 
production in plants. He deals with the 
origin of pairing gametes from spores, with 
the differentiation of (1) eggs and sperms, 
(2) specialised sex organs, and (3) sexual in- 
dividuals (such as the male and female gameto- 
phytes of Equisetum), and with the special pro- 
blems of alternation of generations and partheno- 
genesis. In the case of plants it is plain that the 
function of sex is not to secure reproduction, but 
to secure something in connection with reproduc- 
tion which is not attained by the asexual methods. 
is added on to the older 
does not them. 
The sexual method 
asexual methods, and replace 
| Before sexual reproduction was established there 
were three stages :—The primal capacity for cell- 
division led on to spore-formation by vegetative 
| cells, and that to spore-formation by special cells. 
The origin of sex was marked by the appear- 
ance of minute, motile gametes—reproductive 
cells that pair and fuse. If the material of a 
protoplast is divided only a few times there is 
spore-formation ; if the divisions are more numer- 
ous the cells produced are probably gametes. 
Perhaps the ageing of cells stimulates the numer- 
ous divisions and the production of cells incap- 
able of functioning as spores. Whether the pair- 
ing gametes appear similar (isogamy) or dissimi- 
lar (heterogamy) there is certainly physiological 
unlikeness. They are the bearers of sex-deter- 
miners and corresponding sex-inhibitors, which 
are passed on through generations of vegetative 
cells until conditions favour their expression in 
Ss 
