OBSERVATIONS OF THE MAGNETIC DIP IN THE UNITED STATES. 183 
These observations indicate, that at Hudson, Ohio, the Dips of the Magnetic Needle re- 
mained sensibly stationary from 1838 to 1844; and, that since the latter date, the Dip 
has slightly increased. : 
In order to determine whether the instrument had sustained any injury, I requested 
Prof. C. A. Young, of Western Reserve College, to make a series of observations similar 
to those which I have published in the Transactions of the American Philosophical So- 
ciety, Vol. VIII., page 66. This he accordingly did, and the following are his results. 
The observations were made from April 19th to May 2d, 1859, and each number in the 
two columns headed “ Poles Direct,” “Poles Round,’ is the mean of twenty readings, 
making a total of 1360 readings, besides a double set of readings for azimuths and 180 
degrees. 
Magnetic Dips observed at Hudson, Ohio, by Prof. C. A. Young. 
aaa Poles Direct.| Poles Round. Mean. Dips Deduced. i ae remotes Direct Poles Round. Mean. | Dips Deduced. 
° 7 ° 0 ° 7 ° 7 j ° 7 ° 0 ° 0 ° ’ 
1073 16.0|73 181 re o | 140176 29.5/76 F281 og ae 72 45.7 
OE Tae Heo aah | UMM aR TE ag. 
980/86 41.586 47.95|°° 6 240 81 29.2/81 35.0 eee ata th 
20/74 _6.7/78 eae 60) 150,75 13.8)75 A Nis us eee 
ON te | aaa 
290/84 7.7|84 oir f (84 16.2 J 25084 15.0184 9.9 | (84 TS Niles 
(30/75 19.574 380145 7 | 160/74 6.5)74 7 es aA BG 
Ost STL O8t1k, ago tl? OT |) Canes seaes tual 
300/81 1.83/80 36.6 | [Sl Be) OO Mise BOA; Ie OH) 
{i076 46.9 76 oc We 17073 81.9173 18.6) |r, ae . 
eh is Peis pee o 455 850/73 + 12.5)73 3.1 | 
310/78 7.9178 343} (78 35.2 J : General Mean. 72. 57/1 
As these observations did not agree as well as was expected, a second series of observa- 
tions was undertaken. The whole number of readings in the second series was 2880, 
(being ten of each end of the needle in every position,) besides some 500 or 600 more in 
the re-examination of all readings that seemed either too discordant with the former re- 
sults or suspicious in themselves. The observations were all taken between the hours 
72 and 10 A. M., and the readings for the azimuth 60, 70 and 80 degrees, were all made 
between the hours 84 and 93 A. M. 
The following is the summary of the second series of observations made between May 
4th and June 30th, 1859. 
Magnetic Dips observed at Hudson, Ohio, by Prof. C. A. Young. 
