Before leaving for India, in the end of 1876, it occurred to me that, as almost nothing seemed to be known about atmospheric electricity in the tropics, it would be well if I could take with me the apparatus necessary for making observations on it. I accordingly communicated with Sir William Thomson, who kindly obtained for me a grant from the British Association, for a portable electrometer. This instrument I took with me, and the following are the results of the observations made with it.