Se ne ee ee a 
Magnetic Storm of May 14, 1878. 208 
Art. XXIII.—The Magnetic Storm of a 14, 1878, observed in 
North Amer 
[Communicated by Carlile P. Patterson, Superintendent United States Coast and 
Geodetic Survey. ] 
THE extensive magnetic disturbance of May 14, 1878, of 
which accounts have been given in ature,* and which was 
observed in China, Australia and England, also made its 
record in North America at our magnetic observatory, eee 
lished at Madison, Wisconsin, in the winter of 1876-1877. 
This observatory is in latitude 48° 04’ 29” ‘5, and in longitude 
5h 57™ 3655 west of give in it are mounted a set o 
changes in magnetic d ation and in the zontal and ver- 
tical forces have been seen te since wre “1877, and are 
intended to be kept up for some year he declination traces 
d 
westward, and in part of a great number of small and rapid 
encanto The characteristic Aten of the trace may be 
given as follows 
Madis Greenwich 
mean time. mean = 
dad. h.m d. h. 
The disturbance in declination repre about....14 0 00 A. u 145 58 A. M. 
i A principal westerly} extrem 1 05 703 
A principal easterly extreme reac au. £5624 8 a 
Range of motion 16”: ite after this a series of smaller oscilla- 
tions continue to past noon 
d. h. m. d. h, m. 
ximum westerly — is reached about... 0 16P.M. 6 14 P.M 
‘kad an easterly extre Oba." 6 51 = 
Extreme westerly deflecti n 326° 9 24 
A sharp motion to the eastward commences at__. 540 “ 11 38 
A principal easterly extreme reached at_-_---.--- 624" 16° 0 22 ee. 
Range of motion of principal disturbance 31’°7. 
There is also a westerly extreme about.----.-.---- 110.4 1 08 . 
And an easte tly extreme about e165.) a 4 2 
After 10 p. M. the irregularities gradually subside. 
Last extreme easterly position 151104. M. a 
It will be noticed that at the Greenwich observatory the 
storm commenced on May 14, at 6405" a. M., at Stonyhurst 
observatory at 64 04™, at Zi-ka-wei, near Changhai, also at 6% 
04™ (Gr. time), and at Melbourne supposed at 6 20™; the storm 
may therefore be taken as simultaneous at these places. At 
* Vol. xviii, Nos. 467, 468, 469. + Referring to north end of the magnet. 
