one of the "International Scientific Series," and fits in well with what is perhaps the most important work of the author's life; for it records the development and present position of a doctrine which he has had as large a part as, if not a larger part than, any other man in bringing to the shape in which it is now generally received by chemists. It embraces an historical introduction, containing a concise, accurate, and complete history of the theory of atoms from the times of the Greek philosophers and Lucretius, and from the revival of the doctrine by Dalton to the present time. A second part includes a full exposition of the theory as it is now held and applied. It is described, by the critic in "Nature" from whom we have quoted, as "at once a scientific treatise and an artistic work, . . . marked with a distinct individuality and self-completeness," and as conveying a sharp impression, "without making any great sacrifice of accuracy."
All of Professor Wurtz's later works are characterized by the marks of his strong faith in his own conception of the atomic theory, and for this he has been criticised perhaps by some one whose theory is a little different as too much inclined to treat theoretical considerations as identical with facts, and as, seemingly, supposing facts to be explained when they are only stated in the language of his theory. He has himself given an illustration of the manner in which this may be brought about, by explaining in his Faraday lecture that, whenever we attempt to make well-observed facts and their immediate consequences—the only certain things in the physical sciences—the basis of any general theory, "hypothetical data are apt to mix themselves up with our deductions."
Professor Wurtz has been President of the Academy of Sciences in Paris since 1881. His merits have been recognized by the French Government by the bestowal of the decoration of the Legion of Honor in 1850 and by promotion to the rank of officer in 1863, and to that of commander on the occasion of his acting as a member of the French section of the International Jury at the Great Exhibition in London, in 1869. In July, 1881, he was appointed a Senator for life in the French Senate, by a large majority, and became the third member of the Academy of Sciences who was in the enjoyment of a seat in that body, his two scientific colleagues being M. Robin and M. Dupuy de Lome.
