this journey, a part of which has been made by very few persons before, has never been undertaken under better auspices. This party will explore the upper course of the Rio Doce, the Rio das Velhas, and the San Francisco, with the lower course of the Tocantins and its tributaries, as far as they can; making also collections of fossils in certain regions upon the route. Another party, starting at about the same time, is to keep nearer the coast, exploring the lower course of the Rio Doce and the San Francisco. Mr. Agassiz thus hopes to make at least a partial survey of this great water system, while he himself undertakes the Amazons and its tributaries.[35] In the mean time, the result of the weeks he has been obliged to spend in Rio, while organizing the work of these parties and making the practical arrangements for its prosecution, has been very satisfactory. The collections are large, and will give a tolerably complete idea of the fauna of this province, as well as a part of that of Minas Geräes. A survey of the Dom Pedro Railroad, made under his direction by his two young friends, Messrs. Hart and St. John, is also an excellent beginning of the work in this department, and his own observations on the drift phenomena have an important bearing on the great questions on which he hoped to throw new light in coming here. The closing words of a lecture delivered by him last evening at the Collegio Dom Pedro Segundo will best express his own estimation of the facts he has collected in their bearing on the drift phenomena in other parts of the world. After giving some account of the erratic blocks and drift observed by him at Tijuca and already described in his letter to Mr. Peirce, he added: “I wish here to make a nice distinction that I may not be misunderstood. I _affirm_ that the erratic phenomena, viz. erratic drift, in immediate superposition with partially decomposed stratified rock, exist here in your immediate neighborhood; I _believe_ that these phenomena are connected, here as elsewhere, with the action of ice. It is nevertheless possible that a more intimate study of these subjects in tropical regions may reveal some phase of the phenomena not hitherto observed, just as the investigation of the glacial action in the United States has shown that immense masses of ice may move over a plain, as well as over a mountain slope. Let me now urge a special study of these facts upon the young geologists of Rio, as they have never been investigated and their presence is usually denied. If you ask me, ‘To what end?—of what use is such a discovery?’—I answer, It is given to no mortal man to predict what may be the result of any discovery in the realms of nature. When the electric current was discovered, what was it? A curiosity. When the first electric machine was invented, to what use was it put? To make puppets dance for the amusement of children. To-day it is the most powerful engine of civilization. But should our work have