@cTOBER 27, 1899. ] 
face, the most interesting chapter of the vol- 
ume, is a graceful memorial to his predecessor 
at the Sorbonne; it discusses the methods of 
Laplace, Gauss and Olbers, together with other 
possibilities in the determination of orbits, and 
concludes with a concise résumé of the method 
followed in Tisserand’s exposition. 
In the first chapter Tisserand presents the 
method of Olbers for the determination of par- 
abolic orbits. By this method the calculations 
fall into two parts: 1°. No hypothesis is made 
as to the nature of the orbit, and the six equa- 
tions are combined in such a manner as to 
yield a unique equation ; this combination can 
be made in an infinite number of ways and 
thus yield an infinite number of equations ; 
Olbers effected it in such a happy manner that 
the unique equation assumes a remarkably 
simple form whose simplicity is conserved in 
the second approximation if the observations 
are equidistant. 2°. In the second part the 
condition for a parabolic orbit is introduced, 
thus reducing the number of unknowns to five : 
to the four equations given by the two extreme 
observations is joined the unique equation ob- 
tained in the first part. Four equations in 
four unknowns are to be solved; resort must 
be had to successive approximation. The 
chief advantage of Olber’s method is that the 
only equations which present difficulties of 
computation contain only two unknowns; 
tables of single entry give one of these as func- 
tions of the other. 
The second chapter presents the well-known 
method of Gauss for the determination of the 
orbit of a planet from three observations elab- 
orated in his Theoria motus. 
M. Perchot has increased the usefulness and 
convenience of the book by appending general 
résumés of the formule in definitive form for 
computing together with the numerical calcu- 
lation of the orbit of the asteroid, 1897, DJ., in 
which no detail has been omitted ; this model 
computation and reproductions of Oppolzer’s 
tables VIII. and IX. conclude the work. 
EK. O. Loverr. 
Lexikon der Kohlenstoff-Verbindungen. Von M. 
M. RicHTEerR. Zweite Auflage der ‘‘ Tabellen 
der Kohlenstoff-Verbindungen nach deren 
SCIENCE 
613 
empirischer Zusammensetzung geordnet.’’ 
Hamburg und Leipzig, Verlag von Leopold 
Voss. 1869. 
The work bearing the above title is another 
product of the indefatigable energy and pains- 
taking care of a German chemist. In 1883 Dr. 
Richter gave out his ‘ Tabellen der Kohlenstoff- 
Verbindungen’ arranged in accordance with 
empirical formulas. While that edition con- 
tained 16,000 compounds, and the third edition 
of Beilstein now reaching completion has some 
57,000 compounds described within its spacious 
pages, this dictionary says something about 
67,000. 
The work is conveniently divided into the 
following parts: Introduction, System and No- 
menclature ; List of about 67,000 compounds 
and their percentage composition; Register of 
Proper Names; Table of Numbers for finding 
the Percentage Composition. 
The dictionary is to be issued in about thirty- 
five numbers, the first eleven of which are at 
present in hand. Each number contains sixty- 
five pages and is of the same size, style and 
print as the Lieferungen of Beilstein’s ‘ Organ- 
ische Chemie,’ 3 Auflage. 
In the Preface, which, with the Introduction 
to the system and nomenclature, is given in 
four languages (German, English, French and 
Italian), Dr. Richter states that the work was 
begun ten years ago. Three causes are ascribed 
for the length of time required to complete the 
work: viz., changes of nomenclature at the 
Geneva Convention, the immense number of new 
facts made known in the time and his own 
business engagements. Professor Beilstein’s 
desire to exhibit the percentage composition of 
additional types CHO, CHN, and CHON, 
thereby adding some 20,000 formulas, has been 
complied with. 
The alphabet of the system shown in the suc- 
cession of the elements combined with carbon, 
as determined by the frequency of their occur- 
rence is as follows: 
(PEE OSENE CIB reli h ais Sib 
(2) All the other elements are placed in al- 
phabetical order: A—Z. 
The elements follow each other in horizontal 
and vertical rows according to the number of 
atoms. 
