612 SUMMARY. 



2. Temperature and thickness of ice, and the wind and 



weather. 



3. The barometer. 



4. The temperature of the sea and currents. 



5. The tides. 



6. Specific gravities of salt water. 

 Geodetic measurements. 

 Astronomical observations along the coast. 

 jClagnetic observations for the three magnetic elements. 

 Remarks on the Aurora Borealis. 



Measurement of the velocity of sound. 



Measurement of the motion of glacier in Franz -Joseph- 

 Fiord. 



XIV. The second Swedish Expedition under Professor Norden- 

 skiold. 



In the first Swedish Expedition to Spitzbergen in 1868, in 

 addition to the meteorological, magnetic, and other observations, 

 attempts were made by M. Lemstrom to determine the spectrum 

 of the Aurora, and also the electrical state of the air. His apparatus 

 was not sufficiently delicate to give satisfactory results ; but to 

 M. Lemstrom we owe the discovery of a spectroscope which has 

 revealed several of the lines of the spectrum of the Aurora, not 

 only to himself at home, but also to M. Wijkander in the Arctic 

 regions, on the second Swedish ExjDedition. An account of these 

 results will be found under Aurora (p.737). 



Among the general results of this Expedition, which are not yet 

 published, are contained : 



I. Hourly Meteorological observations. 

 II. Astronomical positions of stations, &c. 



III. Pendulum and refraction observations in great cold. 



IV. Hourly Magnetic observations^ besides observations every 



five minutes on two term days a month in connexion 

 with observations at Upsala. 

 '■ V. Tides and Currents, 



The record of the meteorological observations will be ready very 

 shortly. 



XV. Austro-Hungarian Expedition under Lieut. Weyprecht : 

 Meteorological observations, winds, and ice-drifts. 

 Formation and melting of ice. 



Astronomical observations. 



Magnetic observations, including disturbances of all three 

 magnetic elements. 



The Aurora. 

 The "Manual " also contains an account of a discussion of the 

 temperatures of places in the Arctic regions by M. Dove, to which 

 more recent observations have been added. It also treats somewhat 

 fully of the Aurora, and its relation to the earth's magnetism, to 

 the electrical state of the air, and to observed phenomena of sun 

 spots. 



