Page:Proceedings of the Royal Society of London Vol 1.djvu/206

Rh the latter latitude across the equator, and from thence to lat. 25° S. Within the last-mentioned limits, the diﬁerence was very consider- able, being generally from ﬁve to nine hundredths of an inch, both in the day and the night.

When the ship arrived in lat. 28° S., long. 27° W. (June 7th), the mercury no longer performed the equatropical motions, but was irre- gular and ﬂuctuating until July 11th, when the ship was in latitude 27° S., long. 51° E. The equatropical motions then took place again, and continued with great regularity while the ship sailed up the Madagascar Archipelago, and across the equator, until the arrival of the ship at Bombay, on the 31st of July.

On the 6th of August the barometers were placed on shore, and, from that day to the 12th, the mercury appeared to have a small tendency towards the equatropical motions; from the latter day to the 22nd of the same month, that tendency was so much diminished as to be generally imperceptible.

On the 23rd of August the barometers were again put on board the ship, which left the harbour of Bombay on the 26th. The mer- cury then immediately began again to perform the equatropical mo- tions, and continued them, with great uniformity, down the Malabar coast, across the bay of Bengal, in the strait of Malacca, and through the China Sea, until the ship arrived in Canton river, on the 4th of October. The mercury then became nearly stationary, or, if it showed at times a small inclination towards the equatropical mo- tions, such inclination was not by any means so perceptible as at sea.

The ship remained at Canton till the 2nd of December, and, al- though there appeared at times a slight tendency in the mercury to perform the equatropical motions, the rise and fall was in general so small as to be frequently imperceptible; but, on the departure of the ship from Canton river, the motions instantly took place, and con- tinued until the ship arrived in Bombay harbour, on the 1 1th of J a- nuary 1803.

From that day to the 23rd of May, the ship remained at Bombay; and during the whole of that time, no tendency towards the equa- tropical motions worth noticing could be perceived. On the above- mentioned day, the instant the ship left the harbour, the motions of the mercury again took place, and continued, but not always with equal regularity, until the 2nd of July, when the ship again entered Canton river.

During the time the ship continued at Canton, no appearance of the motions here treated of, worth remarking, could be perceived; but as soon as the ship left the river, on the 13th of September, they again took place, and continued until the 13th of October; when, upon entering the Strait of Sincapore, they appeared to be diminished, but re-assumed their usual appearance as soon as the ship had passed the narrow part of the strait. On the 21st of October the ship arrived in the harbour of Prince of \Vales’s Island, and a great diminution again took place in the equatropical motions; but upon