384 Analyses of Boohs. [Nov. 



an instrument which he has constructed upon similar principles, and 

 which may be termed the volume barometer. The peculiarities of 

 his contrivance depend upon having the surface of the liquid in the 

 tube, and that surrounding it, on a level : that the liquid shall be of 

 such a nature as to have no perceptible tension at common tempera- 

 tures : that it shall not perceptibly adhere to the glass, lest a portion 

 remain hanging in the tube, and the enclosed volume of air be under- 

 valued : that all the observations be taken at the same temperature, 

 or that the influence of the temperature upon the enclosed air be 

 taken into account. 



He recommends it as being very convenient for making the neces- 

 sary reductions for gas mixtures. 



On altitude barometers of the most complete construction, by 

 George Breithaupt, of Cassel. 



The writer states that he has devoted much time to the perfecting 

 of these important instruments. He describes his precautions for 

 purifying the mercury, which he prepares from cinnabar, by distilla- 

 tion with lime. It is then strained through card paper many times, 

 heated nearly to the boiling point, and filtered into the tube. The 

 nonius scale he forms of the most delicate kind, extending to j^ 

 millimetre and ^^ line and adjusts a microscope to it. 



Description of an apparatus for assaying silver, in the wet 

 wa'jy by E. Jordan, of Cassel. This is somewhat similar to the 

 apparatus described by Gay Lussac, in his work upon the assay of 

 silver. It differs in this respect, however, that by the proceeding of 

 Jordan the contents of an alloy are determined in the direct way. 



Observations on the declination and daily variation of the 

 needle at Pekin, 6y Hr Kowanko, member of the Imperial Rus- 

 sian Mission at Pekin, communicated by A. T. Kupffer. The 

 observations were made with Gambey's declination compass. The 

 westerly declination was found to be for March 1832, 2" 15' 42". 

 The westerly progress of the needle from December 1831 to March 

 1832, was 12'. At Petersburgh, during the same time, the easterly 

 deviation was 3', where the total deviation was on the 22d and 

 23d December,' 60 27' 5", and on the 20th and 2 1st March, 6^ 23' 

 58". Hrn. G. Fuss, who preceded Kowanko at Pekin, found the 

 declination there in December 1830, 1° 38' W, in May 1831, 1° 55' W, 

 and in June 1831, !« 48' W. 



The needle reached its easterly variation on 21 st December at 9 a.m. 

 On 22d December at 10 a.m. On 20th March at 9 a.m. , and on 21st 

 March at 9 a.m. While its westerly daily variation was as follows : 

 21st December, 2 p.m. var'=:4' 10' 22d December 2 p.m. var. =2' 

 20th March . 2 p.m. var. =5' 41" 21st March . 2 p.m. var. =6' 



Magnetical Observations at Nertschinsk, communicated by 

 A. T. Kupffer. — Cancrin found the inclination of the needle at this 

 place, on the 5th August 1832, at 10 a.m. GQ'* 33 4'. The declina- 

 tion on 5th August, 2 to 4 p.m., was 4° 14 15" W. 22d September 

 4o7 43 W. 



On the Magnetism of the Earth, by Prof. L. Moser, of Konigs- 

 berg. lu a previous paper, Moser endeavoured to prove, from vari- 



