148 
“T mean that when, as I fully expect, a new edition is 
soon ca!led for, you may here and there insert an actual | 
case, to relieve the vast number of abstract propositions. 
So far as I am concerned, I am so well prepared to take 
your statements of facts for granted, that I do not think | 
the pieces justificatives when published will make much | 
difference, and I have long seen most clearly that if any 
concession is made, all that you claim in your concluding | 
pages will follow. 
“It is this which has made me so long hesitate, always | 
feeling that the case of Man and his Races and of other 
animals, and that of plants, is one and the same, and 
that if a vera causa be admitted for one instant, of a 
purely unknown and imaginary one, such as the word 
*creation,’ all the consequences must follow’’ (vol. ii. 
p. 325. | 
After the first publication of the “ Principles”? between 
the years 1830 and 1833, a great part of Lyell’s time and 
thought was given up to revising, enlarging, and re-writing 
portions of his book during the twelve editions through 
which it passed, Although many valuable corrections were 
made in the original work, its scope and arguments being 
extended, and the whole fortified with a great wealth of 
new illustrations, it may well be doubted whether this 
continual re-editing of the book was not attended with 
some loss in the symmetry of its arrangement and its 
literary excellence. Ina work relating to such a rapidly- 
advancing science as geology, this result, much as it is to 
be regretted, could scarcely be avoided ; but many disciples 
of Lyell, while they refer to the last edition as a store- 
house of facts, will delight to renew their acquaintance 
with an old favourite by reading once more the easily 
flowing periods of the first edition. 
We have dwelt at such length upon Lyell’s relations 
to his great work, as illustrated in the interesting volumes 
before us, that we must defer to a second notice some of 
the other interesting topics which are suggested by their 
perusal. JoHN W. JUDD 
ORGANIC CHEMISTRY 
Adolph Strecker’s Short Text-book of Organic Chemistry. 
By Dr. Johannes Wislicenus, Professor of Chemistry 
in the University of Wiirzburg. Translated and edited | 
by W. R. Hodgkinson and A. J. Greenaway. 8vo, 
(London: Kegan Paul, Trench and Co., 1881.) 
HE new edition of Strecker’s text-book by Prof. 
Wislicenus, published in 1874, is well known as 
giving a concise and comprehensive view of the state of 
organic chemistry at the time of its publication, and some | 
useful additions, relating to recent discoveries, have been 
made by the English translators. 
The classification of organic compounds in this, as in 
all recent works on organic chemistry, is based upon the 
hydrocarbons. All organic compounds of known consti- 
tution are divided into the two great groups, Fatty and 
Aromatic, and in each of these the saturated hydro- 
carbons—paraffins in the first, benzene and its homo- 
logues in the second,—are first described; next their 
mono-substitution derivatives: alcohols, ethers, amines, 
phosphines, &c.; then in succession the di-, tri-, tetra-, 
&c., derivatives. With regard to this matter Prof. 
Wislicenus says in his preface: “The most systematic 
arrangement would be found in the number of carbon- 
atoms in direct union. In each such group of equal | 
NATURE 
[Dec. 15, 1881 
carbon contents the paraffin would come first, next those 
derivatives in which only a single hydrogen-atom had 
been replaced, these being arranged according to the 
valency of the substituting element. Then would follow 
the di-substitution products. . . Next the tri-substituted 
paraffins. . . . This order of arrangement is very valu- 
able for the study of organic chemistry, more so however 
for those moderately acquainted with the subject than for 
beginners. 
early part of a text-book. In this way alone can the 
clear differentiation of the various categories be made 
evident, depending, as they do, not so much on the accu- 
mulation of carbon-atoms, as on the nature and amount 
of the other elements in union.” It is worth while to 
compare these remarks with those made by Roscoe and 
Schorlemmer in their lately-published ‘‘Treatise on 
Organic Chemistry,’ at p. 129 of which we read:— 
“Perhaps the most systematic mode of arrangement 
would be to commence each group (fatty and aromatic) 
with a discussion of the hydrocarbons, and then to follow 
on with a description of the series of substances obtained 
by the replacement of one, two, three, or more of the 
constituent atoms of hydrogen. Such a mode of classifi- 
cation, however, labours under the disadvantage that 
compounds which stand as a rule closely together, as, for 
example, the alcohols CnH,,+,0 and the acids C,H»,Qz, 
are thus found widely separated, whilst other groups pos- 
sessing but little analogy are brought into proximity. 
Hence it is desirable, alike for the sake of perspicuity as 
for the purpose of showing the genetic relationships 
between different bodies, to depart in many cases from 
such a systematic treatment, and arrange the compounds 
according as they are derived one from the other.” It 
will be seen from these quotations that each author re- 
gards the arrangement adopted by the other as the most 
systematic, but prefers his own as best adapted to the 
requirements of the student. 
The additions made to the work under consideration 
by the English editors belong chiefly to the aromatic 
group, but no mention is made of the recent investiga~ 
tions of Nevile and Winther, published last year in the 
Journal of the Chemical Society, on the Bromotoluenes, 
which are especially interesting on account of the light — 
which they throw on the influence exerted by the groups 
or radicles which have replaced certain hydrogen-atoms 
in a benzene nucleus, on the position taken up by other 
radicles which take the place of the remaining atoms 
of hydrogen. Inthe series of paraffins there is an omis- 
sion of the normal Heptane, lately discovered by Dr. 
Thorpe in the turpentine of Pinus Sadiniana; and 
amongst the nitroparaffins no notice is taken of the 
Nitrolic acids and Pseudonitroles. Under the organic 
compounds of boron we miss Dr. Frankland’s Ammonio- 
boric methide, (CH,),B—=N Hy, and Diboric ethopentethyl- 
ate, (C,H;O);B=B(C,H;)(OC,H,)s, in which boron figures 
as a pentad; and under guanidine there is no account of 
the Guanamines, C,+.H,,+,N;, a series of bases disco- 
vered by Nencki in 1874 and 1876, and formed by the 
action of heat on the guanidine salts of the fatty acids. 
The translation reads well, and, with the exception of 
a few instances of somewhat too close imitation of German 
forms, is expressed in good idiomatic English. There 
For the latter I think we cannot dispense 
with the study of homologous series, especially in the 
