76 Scientific Intelligence. 



observed. He has given us his deductions from his observations, 

 and not the observations themselves, for the place of a radiant 

 cannot be directly observed. He should not be surprised if other 

 persons do not therefore at once accept his important deductions 

 as fully proven, and that they are waiting for additional evi- 

 dence. 



2. Washington Observations for 1885, Appendix I. Govern- 

 ment Printing Office. — The report of Lieut. Winterhalter, who 

 was sent to attend the astro-photographic congress in Paris, and 

 to visit certain European observatories, constitutes the Appendix I 

 to the volume of Observations of the U. S. N. Observatory for 

 1885. 



3. List of Obsei vatories and Astronomers ; by A. Lancaster. 

 (3d ed.) Brussels, 1890. — In this third edition of Mr. Lancaster's 

 exceedingly useful book, the position of the observatories and 

 the names of the astronomers in the observatories are corrected 

 to date. Special pains were taken by Mr. Lancaster to secure 

 the most reliable data for the geographical positions. 



4. Astronomical Pajjers prepared for the use of the American 

 Ephemeris and Ndutical Almanac, vol. iv, Washington, 1890. — 

 Mr. Hill gives in this volume his new theory of Jupiter and 

 Saturn, the labor upon which has covered a period of seven and 

 a half years. The method of Hansen is the basis of the develop- 

 ment by Mr. Hill, but the modifications of that method to meet 

 the demands of the problem are very considerable, so that the 

 expression "a new theory" is entirely appropriate. 



5. Publications of the Washburn Observatory ; vol. vi, parts 

 1 and 2. Madison, Wis., 1890. — Part 1 of this volume contains 

 the meridian observations made by Miss Lamb and Mr. Updegraff 

 in 1887. The second part contains observations of double stars 

 made by the director of the observatory, Mr. G. C. Comstock. 

 The observations were made with the fifteen and a half inch 

 equatorial during the years 1887-9. 



6. Terrestrial Magnetism. — In Bulletin No. 18, of the U. S, 

 Expedition to West Africa, Prof. F. H. Bigelow gives a sum- 

 mary of some preliminary results reached in an investigation of 

 the variations of the elements of Terrestrial Magnetism, undertaken 

 in connection with his work on the Solar Corona (see this Journal, 

 Nov., 1890, p. 393). After alluding to the inadequacy of present 

 theories to explain the facts observed, he adds that one cause of 

 vital importance has been omitted from the elements of the prob- 

 lem, namely, the motion of the Earth as referred to the ether in 

 its neighborhood, and he proposes to base an explanation of Terres- 

 trial Magnetism upon the dynamic effects produced by the induc- 

 tive action of the Earth in its motions of rotation and translation 

 through fields of force. In a word, the Earth may be regarded 

 as a cosmical dynamo. Whatever may be the real nature of the 

 ether, it possesses the property of transmitting directed influences 

 according to the laws of energy, which may be regarded as vector 

 potentials of various types. But two of these directed fields of 



