386 Notices respecting New Books. 



known in connection with his epoch-making researches on the 

 behaviour of various substances at extremely high temperatures, 

 and the formation, at such temperatures, of previously unknown 

 compounds, possessing many remarkable properties, that an account 

 of his investigations will be full of interest to many readers who 

 do not intend making a special study of the subject", but who 

 would, nevertheless, like to acquire some knowledge of the methods 

 employed and the results achieved by the great French investigator. 



In Chapter I. the author gives an interesting account of the 

 various types of electric furnace devised by him, and of the special 

 class of work to which each type is best adapted. Chapter II. 

 contains a systematic and exhaustive account of the three varieties 

 of carbon. Chapter III. deals with the preparation, by means 

 of the electric furnace, of a number of elements — chromium, 

 manganese, molybdenum, tungsten, uranium, vanadium, zirconium, 

 titanium, silicon, and aluminium. Chapter IV. is devoted to an 

 account of the new class of compounds formed at these extremely 

 high temperatures — carbides, silicides, borides, phosphides, and 

 arsenides. Of particular interest in this chapter are the suggestions 

 put forward by the author regarding the origin of certain kinds 

 of petroleum and the cause of volcanic eruptions as being due to 

 the action of water on easily decomposable metallic carbides. 

 Chapter V. contains an account of the most recent researches on 

 carbides, silicides, and borides. 



Valuable as is the service rendered by the translator, we regret 

 to say that the work of translation leaves, in our opinion, a good 

 deal to be desired. The determination, on the part of the trans- 

 lator, to follow the original with absolute slavishness has in a 

 number of instances resulted in extreme clumsiness and obscurity 

 of expression, and on page 4 we actually read of " a force of 

 2000 H.P.," a phrase which is surely absolutely inexcusable in any 

 writer with the slightest pretensions to scientific accuracy. 



Index of Spectra. Appendix 0. By W. Marshall Watts, 

 D.Sc, F.I.O. Manchester: Abel Heywood & Son. 1904. 

 Pp. 40. 



This appendix to the author's Index of Spectra contains the arc- 

 spectrum of Molybdenum, and the spark-spectra of Calcium, Scan- 

 dium, Indium, Beryllium, Lithium, Thallium, Potassium, Caesium, 

 Antimony, Arsenic, and Eadium. 



Grundzuge der Theorie der Optischen Instrumente nacli Ahbe. Von 

 Dr. Siegfried Czapski. Zweite Auflage. Unter Mitwirkung 

 des Verfassers und mit Beitragen von M. von E-ohr, heraus- 

 gegeben von Dr. O. Eppenstein. Leipzig : Johann Ambrosius 

 Barth. 1904. Pp. xvi + 480. 



The first edition of this well-known standard work, which was a 

 reprint of the articles contributed by Dr. Czapski to Winkelmann's 

 Handbuch der Physik, appeared about eleven years ago. When a 

 pew edition of the latter work was called for, Dr. Czapski found 



