1871.] Captain Belavenetz — Magnetic Observations, fyc. 361 



action it was not thought right to continue the experiments, which had, I 

 believe, sufficiently proved that force necessary for great muscular work 

 can be obtained by the muscles from fat and starch, though changes in the 

 nitrogenous constituents of the muscles also go on which have as one effect 

 an increased though not excessive elimination of nitrogen after the cessation 

 of the work. 



II. " Magnetic Observations made during a Voyage to the North 

 of Europe and the Coasts of the Arctic Sea in the Summer of 

 1870/'' By Capt. Ivan Belavenetz, I.R.N., Director of the 

 Imperial Magnetic Observatory, Cronstadt. In a Letter to 

 Archibald Smith, M.A., LL.D., F.R.S. Communicated 

 by Mr. Smith. Received February 4, 1871. 



Dear Friend, — Last summer I made a very interesting magnetic 

 voyage, being invited by Vice-Admiral Possiet to take part in the Arctic 

 Expedition with the Grand Duke Alexis, Lieutenant of the Navy. 



The first part of the voyage, from St. Petersburgh to Arkangeslsk (1 1 79 

 miles), by rivers and lakes, I made in a little screw cutter, 27| feet long, 

 7| feet wide, and 2| feet deep, belonging to the corvette ' Variage ; ' the 

 second part of the voyage (1716 miles) in the schooner * Sextant/ 



I visited the "White Sea and the coasts of the Arctic Ocean ; the end of 

 the voyage was in the clipper ' Jemchug' (2461 miles), from Norway to 

 Cronstadt. 



On the way I made magnetic observations, the result of which I inclose 

 in this letter. I will ask you to make them known to General Sabine and 

 to the Royal Society. 



The observations were made by a small compass which has the edge 

 needle, and which is able to turn from one side to the other. Each ob- 

 servation, the data of which are given, was made in different directions of 

 the instrument, turning the instrument on 120° in azimuth, by which the 

 eccentric errors were taken off. In each direction the needle was turned 

 on both sides for correcting the error of the magnetic direction in the 

 needle. Four observations were made for each position of the needle. By 

 this mode of observation the error does not exceed more than +1'. 



In the declination table are given the day and the hour of each observa- 

 tion in order to judge of the daily disturbances of magnetism. It would be 

 very interesting to compare these observations with those made at the same 

 time by photography at Kew, and thereby to deduce the magnetic disturb- 

 ance due to the change of magnetic latitude. 



The inclination was observed by a Kew Inclinometer belonging to the 

 Compass Observatory, made in London in 1865, and examined by Mr. 

 Balfour Stewart. No doubt it is the most useful instrument for this kind 

 of observation. 



The horizontal force was observed by " Captain Belavenetz's Instrument 



