M. KreiPs Magnetic Observations, 
The minimum of inclination was at 8 a.m. in the winter 
months (i.e. November to March) and at 11 p.m. in the re- 
maining months, with the exception of June and July, when 
it took place as early as 7. 30' p.m. 
These results are deduced from the general or monthly 
means of the different hours of observation. Another com- 
bination of the observations in daily means, i. e. the averages 
of all the observations taken on the same day, ought to show 
those alterations which have a period longer than a day and 
less than a year: a monthly period is thus shown; but as yet 
it is only in the horizontal elements that it can be recognised 
with certainty. The observations with the inclinatorium have 
not been brought into the calculation, because they were 
frequently interrupted, and because at first the axis of oscilla- 
tion of the needle was too far removed from its centre of 
gravity. 
12. If the daily means of the times of vibration of the 
horizontal needle reduced to the temperature of 0, are com- 
bined together in such series that the middle of each shall 
coincide with a phase of the moon, and if the means of these 
series are freed from the influence of the loss of magnetism 
of the needle by being reduced to the same epoch, we then 
see that the total means of all the times of vibration observed 
near the new moon, and during the first quarter, are less than 
those near the full moon and in the last quarter. If we 
compare the different months with each other, we see that 
the phsenomenon, as it is here enounced, is only found in the 
eight months from November to June, and that in the four 
remaining months, i. e. July to October, the contrary takes 
place ; for in the latter interval the longest times of vibration 
coincide with the new moon and the first quarter, and the 
shortest times of vibration with the two other phases. 
13. This phenomenon might be thought to be an effect of 
the rotation of the sun round its own axis, which, supposing 
the sun to be magnetic, would cause sometimes one and some- 
times the other of the poles of its magnetic axis to be turned 
towards the earth ; and this hypothesis would also explain 
the alternations of the phaenomena according to the different 
seasons of the year, as the earth is opposite to one or the 
other of the solar hemispheres according as she is in the 
summer or in the winter half of her orbit : but this will not 
hold good. The epoch of the least value of the intensity is 
open to the objection that the time of rotation of the sun is 
two days shorter than the time of the synodic moon, and this 
difference of time combined with the different positions of the 
earth relatively to the sun, would cause the phaenomenon to 
