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Lieut. Elagin/s Determinations of the Dip. [Feb. 11, 



by the English makers Troughton and Simms ; two needles about 8 inches 

 long are observed, and the observations are made in the usual manner, 

 in the magnetic meridian. The dip is observed at the beginning of each 

 year, in the month of March or April ; thus for the year 1868 there was 

 one observation made with two needles the 30th of March, and the dip 

 obtained was 67° ll'-l. The 5th of September Professor Quetelet's son, 

 according to my wish, was so kind as to observe the dip, and obtained 

 almost the same result (that is, 67° 11''0), whilst from observations with 

 the Kew Circle I obtained the dip =67° 6'*77, being 4'*2 smaller. 



Utrecht Meteorological Department. — The observations were made 

 with an instrument not differing much from instruments of this class 

 formerly used in England. It was constructed by Olland, a maker at 

 Utrecht ; the dip is observed every fortnight, in the middle and at the end 

 of each month, with two needles about 8 inches in length. The results of 

 the separate needles are very close to one another, and the dip is generally 

 observed about 9 o'clock in the morning. Simultaneous observations 

 were made by Mr. H. Welers Bethink and myself, each observing his own 

 instrument. The dips obtained are as follows : — 



"With the Observatory instrument. ... G7° 4 7'" 7 



With the Kew Circle 67° 43''3, being 4'*4 less. 



Vienna Meteorological Department. — The Dip Circle was made by Rep- 

 sold, and a description of it is given in the 'Magnetische und meteorologische 

 Beobachtungen zu Prag bei Karl Kreil, sechster Jahrgang, vom Januar 

 bis 31. December 1845/ The instrument is provided with eight needles, 

 whose lengths are about 9 inches each ; the axis of the needle is perforated, 

 and can be turned round the centre of the needle through a definite angle ; 

 each dip is deduced from eight separate sets of observations, by turning 

 each time the axis of the needle through an angle of about 45°. The sepa- 

 rate results derived in this way differ sometimes about 1° from each other, 

 and the means for separate needles differ in some cases about 20' ; so that 

 the determinations of dip with this instrument are very uncertain, whilst 

 the labour to obtain a pretty good result is very great ; at the same time a 

 single determination with one of the Barrow's Circles gives a result nearer 

 to the truth. I must say here that the present Director of the Meteoro- 

 logical Institution in Vienna, Professor Yelynak, was so pleased with the 

 instrument I had from Kew, that he asked me to order one for him of 

 Mr. Barrow. 



The mean result derived from the observations from January 1 to Sep- 

 tember 18, 1868, is =63° 32'-06 ; the result obtained with the Kew Circle 

 is 63° 38'*80, being larger by 6'-/. 



Munich. — Regular observations of absolute dip are not made at the Ob- 

 servatory. The last determined dip was in 1866, in September, and was 

 64° 1 6'*8. The dip for the present time is deduced from the variation of 

 horizontal force and the constant relation between it and the dip as found 

 by Dr. Lamont from a large series of observations ; according to this the 



