abstracts: terrestrial magnetism 31 



The tides in Baffin Bay and in Robeson Channel consist largely of 

 stationary waves. 



One of the most remarkable results established by the Peary expedi- 

 tion is that the semidaily tide wave progresses eastward, and not west- 

 ward, along the northern coast of Grant Land, which shows that the 

 progressive wave from Lancaster Sound and Jones Sound, which passes 

 west of Axel Heiberg Island, governs this tide. 



The fact that-the range of tide coming from the west can be as large 

 as 0.8 foot at Point Aldrich, near Cape Columbia, indicates that land is 

 not far distant towards the northwest. 



In high latitudes the diurnal forces are large; and so if there exist a 

 deep uninterrupted polar ocean, the diurnal tide should approximately 

 follow the equilibrium theory for an inclosed sea. For certain arctic 

 coasts this is the case while for others either the times or ranges depart 

 considerably from the theoretical values. 



Some of the facts tending to establish the existence of land situated 

 between the Arctic Archipelago and the Arctic coast of eastern Siberia 

 are as follows: (1) At Point Barrow the flood comes from the west and 

 Dot from the north; (2) the range of the semidaily tide at Bennett 

 Island is 2.5 feet while it is only 0.4 foot at Point Barrow and 0.5 foot 

 at Flaxman Island; (3) the times of the semidaily tide on the north 

 coast of Alaska do not indicate that the tide, propagated from the Atlan- 

 tic Ocean to Alaska, crosses a deep and uninterrupted polar basin; 

 (4) the diurnal tides at Teplitz Bay, Bennet Island, Pitlekaj, Point Bar- 

 row, and Flaxman Island have less than one half of their equilibrium 

 values, which fact makes the supposition of an uninterrupted polar 

 basin improbable if not impossible; (5) the westward drift of the Jean- 

 nette and the westward drift observed by Mikkelsen and Leffingwell 

 indicate an obstruction in the polar basin. R. A. H. 



TERRESTRIAL MAGNETISM.— Directions for magnetic measurements. 

 D. L. Hazard. Pp.131. Government Printing Office. 1911. 



This publication aims to present the subject so that an observer 

 familiar with the use of instruments but without experience in magnetic 

 work may make observations for determining magnetic elements with- 

 out other assistance than the book itself. The first part is devoted to 

 definitions, explanations of principles, and the derivation of formulas. 

 The three other sections of the book give specific directions for absolute 

 observations on land and at sea and general directions for the operation 

 of a magnetic observatory. At the end of the volume are standard 

 forms of record and tables for use in computation. The volume can be 

 easily carried in the field. R. L. Faris. 



