296 CAPTAIN ELLIOT’S MAGNETIC SURVEY OF THE INDIAN ARCHIPELAGO. 
last three curves of Plate I. are the Keemah curves of the latter end of June or com- 
mencement of July; their morning maximum and minimum at 19 hours, and at 
noon, correspond with the same periods at Singapore. 
At the top of Part 2 of Plate IV. containing the winter stations, the curves of the 
five declinometers are drawn to the same scale, viz. V of arc to 0'35 of an inch : there 
may be seen from these curves, the extreme difference likely to occur amongst instru- 
ments observed nearly simultaneously ; whilst these curves are similar, they are not 
identically the same ; the observations were not taken at the same instant, but one 
after the other in the order of the declinometers*. The curves of Pulo Peesang in 
the same Plate, are similar to the Singapore February curve. The Carimon and 
Booaya curves are similar to one another, but the maximum in the afternoon is 
earlier than the corresponding maximum at Singapore. Part 1 of Plate V. is the 
continuation of the winter curves; the curves of the three declinometers at all the 
stations of Nicobar, Penang, Pulo Binding, Batavia and Padang, agree wellVith the 
same winter period at Singapore. 
In Part 1 of Plate V., at the hours of 6 and 7, there is observable in some instances 
a want of uniformity in the progression of the curve ; in some instances no difference 
is perceptible, in others a minimum. On referring to Plate V. we find there is a mi- 
nimum at Singapore in January, exactly similar to the minima shown in some of the 
curves of Part 1 of Plate V., and at the same hours. 
In Part 2 of Plate V. are given the curves of the stations where the instruments 
were observed during the equinoctial months, both in spring and in autumn. The 
Madras curve, when compared with the Singapore curve, has its morning maximum 
and minimum at 20 hours and at noon; at Singapore at 18 and at 22 hours, two 
hours earlier. Madras is near the line of minimum intensity. 
The observations at Bencoolen were taken for a few days at the end of August and at 
the commencement of September, it is therefore difficult to say to which month they 
belong ; they agree well with the Singapore August curve. The next curves in the 
Plate are those of Batavia in March ; they are exactly similar to the Singapore curve 
in March. 
The Cocos curves taken in September agree well with the Singapore September 
curve ; the form of the morning curve is identical, and the time of the afternoon 
maximum ; but they differ in the afternoon maximum at the Cocos, having a greater 
range than the morning maximum ; the progression of the magnet westward being 
subsequently more rapid till between the hours of six and seven, when there is the 
same faint minimum expressed as in the January curve at Singapore. Noting therefore 
those curves which are in accordance or differing but slightly from the Singapore 
* The observation of No. IV. at 3 a.m. has been omitted in the curve, as on referring to the observation 
book the series was found to be broken on one day in November; but the observation at 3 a.m. was entered, 
and as the scale reading was unusually low, it has reduced the mean reading at 3 a.m., or at 15 hours lower 
than it should be. 
