AT TWENTY-ONE STATIONS IN EUROPE. 



93 



The numbers assigned for the horizontal intensities at Rome and Naples, by 

 M. QuETELET, are, respectively, 1.2471 and 1.2869, differing very considerably 

 from my results. My total intensities agree, however, very nearly with those 

 found by Humboldt and Gay Lussac, which were, for Rome, 0.945, and for 

 Naples, 0.938. 



FLORENCE AND MILAN. 



The observations at Florence were made in the Boboli Gardens; those at 

 Milan in the garden of M. Kramer, near the Porta Nuova. The chronome- 

 ter was compared, at both places, with the observatory clock. 



The same data at Paris, which were referred to under the the head of Rome 

 and Naples, were used in the calculations in the following table. 



Observations at Florence and Milan. 





For Horizontal Intensity 



• 







Place. 



Needle. 



Date. 



Temp. 



m 

 d 



c 



t« o 



. td 



o 



Time of 



Ten 



OsciU'ns 



at 60°. 



Sees. 



Coeffic't 



of 

 Corr'n 



for 



Loss of 



Magn'm. 



Horizontal 

 Intensity. 



Year. Month. 



D. 



H. 



Fah. ° 



Paris 1. 



Florence 



Cylinder 

 Bar 



1838 



May 



28 



21, P.M. 



31, " 



68.2 

 67.0 



2 



2 



700 



32.395 



34.838 



.9947 

 .9985 



Mean, 



1.164 

 1.176 



1.170 



Milan 



Cylinder 

 Bar 



1838 



June 



10 



1,P.M. 

 2, " 



73.7 

 72.1 



2 



2 



600 



33.269 

 35.765 



.9964 

 .9989 



Mean, 



1.106 

 1.117 



1.112 



For Dip. 



Fl( 



)rence, 1838, May 28tli, Needle No. I, 62° 06'.. 



No. 2, " 04 .( 



5 



Mean, 62° 05'. 5 





I 



/[ilan, 1838, June 10th, Needle No. 1, 63° 54'. 1 



No. 2, " 55 .4 





Mean, 63° 54'.7 







Total Intensity at Florence, compared witli Pa 

 " Milan, " " ' 



ris as 



unity, 0.965. 

 " " 0.972. 





The same numbers for Paris being employed as in the preceding calcula- 

 tions, and referring to 1838, 1 thought it might be satisfactory to ascertain if any 

 part of the differences of horizontal intensity, as shown by the two needles, 

 (amounting, in the results at Florence and Milan, to .012 and .011,) could be 

 explained by an erroneous correction for loss of magnetism. Referring the 

 horizontal intensities to 1837, however, when the correction has the contrary 

 effect from that in the table, the same difference results. 



VII. 



