In a paper on the Temperature of Man, which I had the honour to submit to the Royal Society in 1845, and which was published in the Philosophical Transactions for the same year, I expressed the hope of being able to continue the inquiry in the West Indies, to which I was then about to proceed. In the present communication I propose to lay before the Society the results of the trials made whilst there, viz. during a period of about three years and a half, exclusive of trifling interruptions, and of one prolonged through several weeks, between June 1847 and October of that year, owing to illness.