Miscellaneous Intelligence. 405 



10. Elements of Mineralogy, Crystallography and Blowpipe 

 Analysis from a practical Standpoint ; by Alfred J. Moses 

 and Charles Lathrop Parsons. New enlarged edition, pp. vii, 

 44. New York, 1900 (D. Yan Nostrand Company). — This new 

 edition of the Mineralogy by Professors Moses and Parsons 

 appears in an enlarged and much improved form. The special 

 features of the original work which made it particularly suitable 

 for the use of the technical student, or the worker in the field, — 

 as the classification of species and their clear and concise descrip- 

 tions — have been retained, while the crystallographic portion has 

 been rewritten and developed so as to conform to the modern 

 method of treatment and classification. Other parts have also 

 been revised and improved, so that the work as a whole may well 

 commend itself to a wider range of students and readers than 

 heretofore. 



III. Miscellaneous Scientific Intelligence. 



1. Latitude-variation, Earth-magnetism and Solar activity. — 

 The following conclusions are reached by J. Halm after a discus- 

 sion of the above subject. 



(1) The changes in the motion of the pole of rotation round the 

 pole of figure are in an intimate connection with the variations of 

 the earth-magnetic forces. 



(2) Inasmuch as the latter phenomena are in a close relation 

 with the state of solar activity, the motion of the pole is also 

 indirectly dependent on the dynamical changes taking place at 

 the sun's surface. 



(3) The distance between the instantaneous and mean poles 

 decreases with increasing intensity of earth-magnetic disturb- 

 ance. 



(4) The length of the period of latitude-variation increases with 

 increasing intensity of earth-magnetic disturbance. 



(5) In strict analogy with the phenomena of aurorae and of mag- 

 netic disturbance, the influence of the eleven-year period of sun- 

 spots, as well as of the "great" period, is clearly exhibited in the 

 phenomenon of latitude-variation ; and the same deviations from 

 the solar curve as are manifested by the aurorse are also evident 

 in the motion of the pole. 



(6) The half-yearly period of the earth-magnetic phenomena 

 influences the motion of the pole of rotation in such a way that 

 its path, instead of being circular, assumes the form of an ellipse, 

 having the mean pole at its center. 



(7) The half-yearly period also explains the conspicuous fact of 

 a rotation of the axes of the ellipse in a direction opposite to that 

 of the motion of the pole.— Nature, No. 1610. 



2. The location of the South Magnetic Pole. — The October 

 number of the Geographical Journal contains an interesting 

 account by C. E. Borchgrevink on the " Southern Cross " Expe- 

 dition to the Antarctic in 1898-1900. The party wintered at 

 Cape Adare on South Victoria Land, in latitude 71° S. and car- 



