Magnetic Dip. 



391 



Variations of Magnetic Dip with reference to the Moon's Age. — An examination of the mean variations in 

 the first portion of Table LIV. will shew that the magnetic dip is a maximum when the moon is in opposition, 

 and a minimum when in conjunction. This result is also evident in the following means of groups : — 



14 days to 16 days, Full Moon, 0'-456 



17 20 ... 0'-540 



21 24 - 0'-328 



25 28 ... 0'-085 



29 days to 1 day, New Moon, 0'-064 



2 5 days, 0'-062 



6 9 ... 0'-215 



10 13 ... 0'-511 



This result agrees generally with that obtained from the incomplete series of observations for 1843. In 

 1843 there was the appearance of a secondary maximum at conjunction ; in 1844 there is the appearance of a 

 secondary minimum at opposition. 



Variations of 3Iagnetic Dip with reference to the Moon's Position in Declination. — The general appear- 

 ance of the quantities in the second portion of Table LIV. is that of a ma.xinium of magnetic dip when the 

 moon is near the equator, and a minimum when it is farthest noi-th and farthest south. The following are 

 means of groups : — 



27 days to 1 day. Moon farthest North, 0'-176 

 2 5 days, 0''245 



6 8 ... c-sgo 



9 12 ... 0'-222 



13 days to 15 days, Moon farthest South, O'llO 



16 19 ... 0'-156 



20 22 ... 0'-342 



23 26 ... 0'-404 



Both maxima occur when the moon is fi'om one to tlu-ee days north of the equator, 

 partially obtained from the incomplete series of observations for 1843. 



This result was only 



TABLE LV. — Diurnal Variations of Magnetic Dip for each Month in 1844, as deduced from 



Tables XXVII. and XLIII. 



