Having had occasion to mention the effects produced by volcanoes, I shall here insert, in compliance with the wish of a respectable friend, some observations on those of India and Africa. Though water has the superiority in _Malayala_, and the whole land is in a manner inundated, traces may be found amidst it of earthquakes; and also, though seldom, of the effects produced by electric fire. In the month of December 1784 a general agitation of the earth was perceived there in the night-time, which continued about two seconds. Such a phenomenon is called in the Malabar language _Bhumikulacam_, and in the Samscred _Bhucialana_. The mountains of _Barcale_ and _Kidàculam_, which contain a great deal of iron and other highly inflammable substances, are, in all probability, the principal reservoirs which give rise to such concussions in the earth. I never had an opportunity myself, during my residence in India, of observing a volcano; but we are told by Father Tiefenthaler, Anquetil du Perron, and Thevenot, that, in the province of _Nagaracotta_, the capital of which, having the same name, lies, according to Rennel, in the latitude of 32° 20′, and the longitude of 73°, (properly 72° 47′,) there is a hole below some rocks which throws out flames from time to time with a loud noise, and for that reason is called _Givàlamukha_ or _Shvàlamucha_, that is, the fiery mouth or fiery nostrils. The Indian worshippers of fire make frequent pilgrimages to this place. Another volcano is situated on the river _Sarayuva_, in the latitude of 3° 25′, and the longitude of 77° 27′, in the territories of king _Doulou Bassanaar_. This volcano throws up, at the same time, fire, air and water, and occasions frequent earthquakes, which are felt all over the province[256]. The circumstance of fire, air and water thrown up at once, induces me to adopt the opinion of those who believe that all volcanoes are connected with the sea, or at least some river, and that they never disengage electric matter, in a violent manner, except when it is concentrated and pressed together by water. My grounds for this opinion are as follows: all the volcanoes I ever had an opportunity of seeing, lie either close to the sea, or to some large river. Thus the before-mentioned volcano, in the territories of _Doulou Bassandar_, is situated, according to the account of Father Tiefenthaler, not far from the river _Sarayuvà_, called by others the _Sardjou_. The volcano in the Isle of France, which has thrown up flames for several centuries, has left on the island a grey, porous, ferruginous kind of lava, traces of which may be discovered in every part of it[257]. On various mountains of the island, which lie at a distance from the sea, there are found a great many calcareous substances, and different kinds of petrified muscles and shell-fish, which have nearly their natural form, so that they can be clearly distinguished from each other. To