464 



On the Swedish Polar Expedition. 



[June 18, 



the curves in terms of the Daniell's cells is shown for every value of the 

 charge of the reservoir. 



This apparatus has scarcely been in use for a sufficiently extended period 

 to allow of any reliable deductions being made as to the existence of laws 

 in the variations of the force of atmospheric electricity, or of any relations 

 that may exist between this and other meteorological phenomena. Some 

 facts, however, can be already gathered from the curves obtained. These 

 are, first, the periods of maxima and minima, which are most distinctly 

 shown. The former occurs at from 30^^ to 30^ a.m., the latter a^t 

 from 1 P.M. to 3 p.m. A second maximum at from 9 to 10 p.m., and a 

 second minimum at from midnight to 2 a.m. are also indicated. 



The greatest disturbances take place during our northerly winds, especi- 

 ally in dry hot weather, when a very great negative tension often occurs, 

 so strong as to be beyond the measuring-power of the instrument, in which 

 case sparks may be generally obtained from the air-electrode. The usual 

 turmng of the wind from N. to S.W. is always accompanied for a short 

 period by an almost equally high positive tension, but during strong and 

 hot northerly winds the high negative tension lasts as long as the wind 

 blows strong and dry. 



XII. ^' Further particulars of tlie Swedish Polar Expedition.^' In a 

 Letter addressed to the President, by Prof. A. E. Norden- 

 SKioLi). Communicated by the President. Received June 12, 

 1868. 



Stockholm, June 7th, 1868. 

 Sir, — I had last night the honour of receiving your letter, and hasten 

 to express my gratitude for the offer of some magnetical instruments. As 

 an able eleve of Prof. Edlund, Dr. Lemstrom, will join the expedition, ex- 

 clusively for studying the meteorology and terrestrial magnetism of these 

 remote regions, I hope that these instruments will be often and advan- 

 tageously employed. But the expedition will start from Gottenhurg the 

 \st July, or from Tromso the 9th July. The boxes can be addressed to 

 Count Ehrenward, Gottenhurg, or Consul Aagaard, Tromso. Excepting 

 myself and two officers of the Navy (Capt. Baron v. Otter and Lieutenant 

 Palander), the expedition will consist of — 



Doctor Malmgren, * 



Smitt, 



„ Nystrom, 



Mr. HolragreD, 



Doctor Fries, 1 ^ • z 

 -r, \ Botanists. 



Bergren, J 



Doctor Lemstrom, Physiker." 

 A Geologist, a Conservator, and about 20 Mariners. 



>■ Zoologists. 



