Miscellaneous Intelligence. dll 
On some observed changes in Vorticella; by A. H. Tuttle. 
Remarks on a Standard of Powers for Microscopical Objectives and Eye 
Pieces; by R. H. Ward. 
10. On the Microscopic Structure of Eozoon Canadense; by E. Bicknell. 
$2 99 
3. On the relation of the Auroras to Gravitating Currents ; by 
Pury Earze Cuase, Professor of Physics in Haverford College. 
___ (Read before the American Philosophical Society, May 5th, 1871.) 
—Prof. Loomis’s observations of the number of auroras in each 
: month of 1869 and 1870 (Amer. Jour. of Science, III, S., i. 309), are 
; specially noteworthy, both because of the careful accuracy of the 
rver, and because they are the first published observations 
which furnish satisfactory data for an approximate determination 
f : 
festations of terrestrial magnetism, it seems reasonable to look to 
hem for some additional evidence upon the question of the rela- 
i it e 
between hyetal and magnetic curves (see Proc. A. P.S., x, 368), 
eS 
=a 
nm 
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— 
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ye | 
S 
7) 
ede 
5 
co 
a 
foe] 
ee 
i] 
a 
= 
=) 
et 
fe) 
4 
ta 
ot 
a 
5 
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ic) 
is3) 
3 
or 
m 
ma in the morni g e ed gitud : 
tween Philadelphia and New Haven being less than 23°, It 1s no 
likely that there is any material difference in the daily ram-curves 
at the two places. : G 
order to make the curves fairly comparable, both in regar 
to the times and the magnitudes of deviation, I treated the auroral 
SE cat 
