Vertical Component of Magnetic Force. 



377 



TABLE XLI. — Means of the Diurnal Kanges of the Vei-tical Component of Magnetic Force, with 

 reference to the Moon's Age, Declination, and Distance from the Earth, for 1844. 



Table XLI. has been formed from Table XL. in the manner described for Table II. 



Variations of the Diurnal Range of the Vertical Component tvith reference to the Moon's Aye. — ^The means 

 in the first portion of Table XLI. shew that the diurnal range of the vertical component is a minimum about 

 conjunction and a maximum about opposition. The follomng are means of gi'oups: — 



14 days to 16 days. Full Moon, 0-001238 



17 20 ... 0001149 



21 24 ... 0-000544 



25 28 ... 0-000446 



29 days to 1 day, New Moon, 0-000540 



2 5 days, 0-000463 



6 9 ... 0-000688 



10 13 ... 0-001221 



Here also, as in the case of the horizontal component, there is an appearance of a secondary maximum at 

 New Moon, but it is not by any means distinct. 



Variations of the Diurnal Range of the Vertical Component with reference to the Moon's Declination. — This 

 result is also well marked in the means in the second portion of Table XLI. The diurnal range of the vertical 

 component is a minimum when the moon has its greatest north and south declination, and it is a maximum 

 when the moon is near, but north of, the equator. The following are means of groups : — 



27 days to 1 day, Moon farthest North, 0-000578 



2 5 days, 0-000930 



6 8 ... 0-000850 



9 12 ... 0-000657 



13 days to 15 days, Moon farthest South, 0-000626 



16 19 ... 0-000773 



20 22 ... 0-000872 



23 26 ... 0-000946 



MAG. .\.ND MET. OBS. 1844. 



6c 



