144 
VICE-ADMIEAL SIE C. SHAD WELL ON TEEEESTEIAL MAGNETISM. 
Reducing the observations at Malta recorded in Table I. to the same epoch, we have, 
1873-52, mean dip 51° 40 ,, 7. Consequently we have 
1861-97 Dip 62° 17'-3 N. 
1873- 52 51° 40'-7 N. , 
Interval . . . 11-55 Change . . . 36'-6 
And iS= 3 '' 16 > mean annual change. North dip decreasing. 
3. Observations at Singapore on April 25, 1857, or 1857-31. — The mean concluded 
dip at Singapore was 13° 21'*2 S. The observations at Singapore recorded in Table II., 
reduced to the mean epoch 1874-45, give as the mean dip 13° 16' - 3 S. Hence 
1857-31 Dip 13° 21'-2 
1874- 45 13° 16'-3 
Interval . . . 17-14 Change . . . 4'-9 
4-9 
And jy-j^ = 0'-29 nearly. South dip decreasing. 
4. Observations at Hong Kong. — Former observations at Hong Kong on May 26, 
1857, Feb. 22, 1858, and Dec. 12, 1859, gave, as the values of the dip at the Wellington 
Battery at Hong Kong, 31° 26'-0, 31° 25'-3, and 31° 28'-5 respectively. 
Hence, reducing to the mean epoch, we have 1858-49, dip = 31° 26'-6 N. 
Similarly the observations noted in Table II. give 1873-50, dip 32° 18'-2 N. 
Interval 15 years. Change 51'-6. 
51*6 
And -jg- = 3'-44, mean annual change. North dip increasing. 
5. Observations at Canton on Jan. 19, 1858, or 1858-05. — The dip at Canton was 
32° 34'-5. 
Reducing the observations recorded in Table II. to the mean epoch, we have 1872-20, 
dip 33° 38' N. Interval 14-15 years. Change 6 3' *5. 
63-5 
And p 4 . 15 — 4' J 49, mean annual change. North dip increasing. 
6. Observations at Shanghai. — Former observations at Shanghai on June 10, 1858, 
and Nov. 24, 1858, gave as the values of the dip 45° 18'*3 and 45° 19'-4 respectively. 
Hence, reducing to the mean epoch, we have 1858-67, dip 45° 18 ,- 8 N. 
Similarly the observations recorded in Table II. give 1873-38, dip 46° 16'*9 N. 
Interval 14-72 years. Change 58'T. 
And y^ 7 ^ = 3'-95. North dip increasing. 
7. Observations at Woosung. — Former observations at Woosung on Nov. 28, 1858, 
gave the dip 45° 2' -5 N. 
On Nov. 16, 1872, the dip was 46° 4'. Hence in 13-97 years the total change by 
these observations has been 61 ,- 5. 
And “^=4'-40, the mean annual change. North dip increasing. 
