of years, not only for the French and not only for the British, but for all nations. Therefore we here in England, we in this Society, will send forth a very hearty word of congratulation to the French, and especially to Colonel Tilho, for the great work which they are doing in Central Africa. He has made very important geographical discoveries, and has referred to new methods of geographical observation. Wireless telegraphy for the purpose of determining longitude is a comparatively new method, but one which is vastly valuable, because, as we who have tried to determine longitudes in far-away places know, in old days it was impossible to get the longitude at all exactly. We could get the latitude fairly accurately, within a few hundred yards, but longitude we could never get to within a few miles. Now by means of wireless telegraphy we are able to get longitude with almost complete exactitude, even in the heart of the French Sudan. Colonel Tilho has also made a slight allusion to another modern invention which I think in future will prove of great service, and that is the aeroplane. We shall hear more of that at our next meeting; but when you see those vast waterless regions, when you hear from Colonel Tilho of the enormous difficulty in getting across them with camels, then we see of what use the aeroplane might have been made for preliminary geographical reconnaissance. Those two inventions, I am certain, will be of enormous service to geography. I now wish on your behalf to tender to Colonel Tilho a most hearty vote of thanks for his lecture this evening, and also for his great kindness, at considerable personal inconvenience, in coming across from Paris to give us this paper. FOOTNOTES: [Footnote 1: A sort of camp-followers whose business in life is warfare in all its branches except that of fighting: experts in all manner of desert craft, scouts, flank-guards, finders of strayed camels or sorely needed wells. Swift to detect the incompetence or bad faith of local guides, they form the necessary complement to the fighting strength of any expedition in Central Africa.] [Footnote 2: This account will be published in the next number of the _Journal._—ED. _G.J._]