172 



Sobescianum, fein ^crnrol)r an,^uitjcnben unb burc^ ©palts 

 Öffnungen ju beobachten, fallet} mi)nte 1679, alö er ©anjig 

 befucfete, biefen JPeobacfcfungen, beren ©enauigfeit er iibrigenö 

 übermäßig anrill)inte, bei. .Sodmoö 93b. III. @. 60, 106 (3lnni. 

 2 unb 3), 154, 317 unb 355 ("Uwm. 13.) 



** (@. 60.) ©puren ber taglicijen unb ftiinblidjen SSeränber^ 

 liebfeit ber tnagnetiWen 9tbJveict)un9 Ratten bereite in 2onbon 

 ^eüibranb (1634) unb in @iam ber «Pater ^acl)arb (1682) erfaunt. 



" (@. 61.) sßergl. Äoömoö 93b. I. @. 432— 435 «Unm. 29. 

 2)ie »ortrefftidje Souftruction ber, mdf 58orba'>-< Stngabe juerft »on 

 2enoir angefertigten Boussole d'lnclinaison, bie 9)?öglirf?feit freier 

 unb langer Schwingungen ber 9?abel, bie fo febr »erminberte 

 Oieibung ber Rapfen, unb bie richtige Slufflellung beö mit gibellen 

 »erfeljenen 3n|lrumentö ^aben iie genaue g)?e(Tung ber örbfraft 

 unter verfcf)iebenen ^onen juerjl möglicb gemacbt'. 



«* (S. 63.) Die ^c^iiUn, mit welc^jen bie folgenbe ^afel aiu 

 ^ebt (j. 93. 1803—1806), beuten auf bie @poc()e ber gSeobacbtung; 

 bie in klammern bem 2;itel ber ©cferiften beigefügten j?ablen aber 

 auf bie, oft fe^r »erfpatete «ßeröffentlic^ung ber 58eobarf)tungen. 



•"• (@- 66.) «Waluö (1808) unb 9Irago'ö (1811) einfarbige unb 

 cbromatifcbe «Polarifation beö Siebtel, f. .Äo^moö 93b. 11. a. 370. 



"* (@. 67.) Äoömo^ 93b. l. ®. 186 unb 429 Olnm. 17. 



'' (®. 68.) »Betöre the practice was adopted of delcrmining 

 absolute values, ihe mosl generally iised scale (and which still 

 conlinues to be very frequently rcferred lo) was founded on 

 Ihe time of Vibration observed by Mr. de Humboldt about the 

 commencement of the present Century at a Station in the Andes of 

 South America, where the direction of the dipping-needle was 

 horizontal, a condition which was for sorae time erroneously 

 supposed to be an indication of the minimum of magnetic force 

 at the Earth's surface. From a comparison of Ihc limcs of 

 Vibration of Mr. de Humboldt's needle in South America and 

 in Paris, the ratio of the magnetic force at Paris to what was 

 supposed to be its minimum, was inferred (1,348); and from the 

 results so oblained, combined with a similar comparison made 

 by myself belween Paris and London in 1827 with scveral niag- 

 nets, the ratio of the force in London to that of Mr. de Hum- 

 boldt's original Station in South America has been inferred to 



