Chemistry and Physics. 425 
the 22d, and is completed in about ten days, after which the maximum 
daily variation is to the westward, and at a mean equal to the eastern 
variation of the preceding six months. 
(2.) There is an annual variation in the intensity of terrestrial magnet- 
a ism, of small amount indeed, but affecting both the northern and south- 
ern hemisphere i in oy same manner, the intensity being greatest when 
the ~< is in perigee, and least when it is in apogee. 
Pe It being wall’ known that all the i instruments in magnetic ore 
jon are from time affected by disturbances, or storms as the 
<a welled, these disturbances have been found to be mee. toa pei 
odie fluctuation. This period has been re ide orrespond with 
that assigned by Schabe,to the spots on the solar 
(4.) It has been clearly shown that there is a aia in magnetic de- 
clination dependent on the change of the moon’s position in relation 
to the meridian of the place of observation, and having, pee re, for 
its period the lunar day. This although first aot ing by Sabine from a 
single set of observations, was fully proved by Kriel from Sbenteaiinas 
made in the Austrian Slates before the: publication of the paper of 
which we are stating the substance 
Finally, the hypothesis which ascribes the variations in the phenom- 
ena of terrestrial magnetism to local variations of temperature is com- 
pletely igg 
not hope, that the relations of mp pee of the earth to 
the two hed wile bodies which exert the est influence in other res- 
pects upon our planet, having been thus sohaleaeels shown, a basis is 
now provided upon which to geen a science that wil be as simple in 
empiric propositions, which although true, have been founded on 
Zeneral law. Henceforth it would seat to be as closely within the 
reach of mathematical methods as the 
7. On the Stauroscope of Prof. Fr. von Kobell, (omnes om this 
Journal by S. W. Jounson, from a paper by von Kobell; a e Ge- 
lehrte Anzeigen, Mar. 30 and April 2, 1835)_—This sehen con- 
Sists of two peste as shown in 1 figure , one of which aaaa, is 
mirror of black glass, upon whiche by paler corals of the tourma- 
line, is seen the well known black cross. At its lower end, this cylinder 
has a graduated semicircle (fig. 2, half size) marking 90° either side of 
Phragms u which the crystals are mounted for observation. The 
Wiltion of the arysthle oe examined is shown at 3, fig. 1. Figure 3 
Tepresents one of the circular diaphragms upon which is accurately 
64 
Szconp fet Vol, XIX, No. 57.—May, 1855. 
