published his preliminary report. His conclusion is that no navigable channel is possible between the Tuyra and the Atrato without locks or tunneling.

Dr. A. Le Plongeon has been engaged for some time in researches in Yucatan among the ruins of Chichen Itza, Uxinal and Aké, and those of the once famous islands of Azumel and Mujeres, and has made many interesting discoveries. He has taken many valuable photographic views of ruins, structures and hieroglyphics, and discovered a remarkable statue which was buried twenty-one feet in the ground. He also discovered some other figures in the Island of Mujeres; he thinks that relations formerly existed between the people of Yucatan and the inhabitants of the islands on the west coast of Africa, as he finds many things resembling the Guanches, the early inhabitants of the Canary Islands, whose mummies are yet found in the caves of Teneriffe, and in other islands of the group.

In South America Major D. A. Rivara and M. A. Werthemen have been exploring in the mountains of Peru, M. Weiner in Bolivia, and Signor F. P. Moreno in Patagonia. They have been measuring the heights of mountains and seeking the sources of rivers. Many interesting facts have been learned.

There have been many explorers in Asia; in Palestine, Persia, Turkestan, Thibet, China, India and Japan. Herr E. Knipping has been engaged in extensive surveys in Japan, and has completed a large map of the country, which will soon be published. He was last surveying a route from Kobi to Tokio, a distance of over 3000 miles.

Mr. Wojeikoff completed his meteorological journey round the world, during the course of which it will be remembered we had the pleasure of seeing him at one of our meetings. His last visit was to India, Java and Japan, and he made an excursion into a part of the interior of Japan never before visited by Europeans.

When I referred to Mr. Stanley in my last address, he had finished his expedition to Lake Akengara, south-west of Lake Ukerewe, and was on his way to Lake Tanganika to explore the country south of the Mwutan Nizige, and north-west of that lake, in the hope of reaching the Mombutto country at the north, so as to connect his own discoveries with those of Schweinfurth, across the equator. It will be remembered that I mentioned last year that Lieut. Cameron circumnavigated Lake Tanganika, and concluded, from his own observations, that he had discovered the outlet of the lake in the River Lukuga, flowing from it on the western side. An ordinary traveler would have been satisfied with Cameron's survey and his conclusion as to the outlet, but Stanley, in the true character of a geographical explorer, determined to go round the southern part of the lake himself, and the result was that he ascertained by a detailed survey and careful soundings that the River Lukuga, instead of flowing out of the lake, flowed into it.

After completing this work, Stanley started with a force of 140 porters for Nyangwa, the farthest northern point attained by Livingston or Cameron, carrying his boat, the Lady Alice, with him. in sections. Stanley reached this place in November, 1876, after a journey of about 350 miles in forty days; in itself, a remarkable geographical feat. Those only who are acquainted with the dangers and difficulties of African exploration, know how frequently the most sagacious conclusions, founded upon what seemed to be the most trustworthy information, have not only been attended by failure, but with the most disastrous results, can fully appreciate what Stanley undertook, and the hazard he ran in determining to follow the Lualaba river in its northerly course. The river ran to the north, apparently in the direction of the sources of the Nile. He had Livingstone's conviction that it was the remote source of that river. To follow the river, however, in its northerly course, might lead him, if his theory should not be verified, into the interior of Northern Africa, where he would be, with a large body of followers, without supplies, and in a state of utter destitution. He appreciated the great risk he ran, but after fully considering it, he came to the bold determination to follow up his theory, and in this exhibited the same geographical instinct which he has referred to as such a remarkable faculty in Captain Speke, the discoverer of Lake Ukerewe. He accordingly started to follow the river to the north. He reached the Atlantic coast in August, 1877, having made a journey from Uyangwa down the river to its mouth, a distance of about 1,800 miles, passing on the way fifty-seven cataracts.

When we saw Mr. Stanley here in the society, his hair was black; it is now said to be entirely white. Of the 350 men with whom he left Zanzibar, in 1874, only 115 reached the Atlantic coast, and 60 of these, when at the journey's end, were suffering from dysentery, scurvy and dropsy. He was on the Congo from November 1, 1876, to August 11, 1877,-a period of over nine months; so that his promise to the native followers was fulfilled, that he would reach the sea before the close of the year.

It remains only to refer to the geographical knowledge which has been obtained by this remarkable exploration. The entire area drained by this great African river, Stanley computes at 860,000 square miles, 450,000 of which are taken up by the great basin and the maritime regions of the west. The source of the Congo, as now ascertained, is in the high plateau south of Lake Tanganika, in a country commonly called Beza, or Ubeza, but from Moesa Lake to the river Lualaba no European knows anything of its affluents. The Congo issues from Lake Bembo, called by Livingstone, who discovered it, Bangwelo. Descending beyond 17° E. longitude, the Congo spreads out into an enormous breadth, and then slowly contracts between hills, when it thunders down, steep after steep, for 180 miles, and then flows as the ma

jestic and calm Lower Congo. In this 180 miles it has a fall of 585 feet. Stanley found the people in this region very friendly. It is navigable for 110 miles from its mouth to the first rapids and beyond them for 835 miles, while the great affluents he estimates which flow into it from the north and south would give 1,200 miles and perhaps more. He estimates its greatest affluent, the Ikelemba, to be over 1,000 miles in length, the Nakuta or Kwango to be over 500 miles, while there are four or five others which, from their breadth, he thinks, should be navigable for great distances. The Nile, he says, has greater length than the Congo, but the Congo could furnish water for three Niles, and it is a much more valuable river for commerce than the Nile, as the Congo has its rapids concentrated in two places, and is not, like the Nile, frequently interrupted by rapids. The upper rapids, where all navigation westward on the Upper Congo terminates, has six great falls, while the lower series has sixty-two important falls and rapids, with many minor ones. Once above the lower cataracts, he says, we have the half of Africa before us, with no interruption like the desert regions of the Nile, but one vast populous plain, no part of Africa with which he is acquainted being so thickly inhabited. The term villages, he says, can scarcely be applied, for it is a collection of dwellings, and there are towns in some places two miles long, with one or more broad streets, and rows of neat and well-built houses, superior to anything to be found in Eastern Africa.

Fault has been found with Mr. Stanley, especially in England, for the warlike contests and destruction of savage life that attended his exploration, which it has been said will make it difficult for any future explorer to follow in the same direction, and which the objectors attribute to a too ready disposition on his part to employ fire arms instead of trying conciliatory measures. He was attacked in the beginning and continued to be attacked until he came to that part of the river where natives dwelt who had intercourse with the Atlantic coast, but as he has stated, and as there is every reason to believe, he acted throughout entirely on the defensive.

In no other way would it have been been possible for him to have followed the river as he did for 1,800 miles, and none but a man of his indomitable perseverance, courage, sagacity and tact could have carried through such an exploration, which is one of the most remarkable on record. When his exploration of the Congo is taken in connection with what he did in tracing the fardistant sources of the Nile, in the river that enters at the southern part of Lake Ukerewe (Victoria Nyanza); his successful circumnavigation of that great lake; the investigation of its tributaries, and what he ascertained in respect to Lake Tanganika, both on his first and his last examinations of it, it may be truthfully said that no man has ever, in explorations upon the land, done so

much for the acquisition of geographical information. In respect to the great water system of Africa, in its connection with the mystery of the Nile and the mystery of the Congo, he has solved an enigma that has attracted the attention of the world for ages, and fixed his name in the foremost rank of geographers, explorers and travelers.-Condensed from the New York Tribune.

MICROSCOPY.1

MICROSCOPICAL SECTION, TROY SCIENTIFIC ASSOCIATION.- A regular meeting of this section was held on the evening of April Ist, Dr. R. H. Ward, chairman of the section, in the chair.

Minutes of the last regular meeting and record of the subsequent soirée were read and approved.

Dr. Ward announced an invitation from the microscopists of Indianapolis to their fellow-workers throughout the country, to attend a National Congress of Microscopists in that city, commencing on Wednesday the 14th of August next, and adjourning in time for members to attend the meeting of the American Association at St. Louis, one week later. The biological section of the Indianapolis Lyceum of Natural History, assisted by many influential citizens, will make ample arrangements for the comfort and economy of visitors from abroad, both in obtaining reduced rates of travel and in the most liberal entertainment while in the city. A detailed statement of the proposed work of the congress and of the facilities offered by the local management will be given to the public, within a few weeks, in the form of a circular. The committee of arrangements, consisting of Prof. E. T. Cox, chairman, Mr. E. Sharpe, Dr. Henry Jameson and Dr W. W. Butterfield, secretary, have received the individual endorsement and promise of coöperation of leading microscopists, and now formally extend an invitation to the microscopical societies and workers throughout the country, with the assurance of a successful meeting. Such a congress, with its opportunities for stimulating microscopical work, discussing questions of general importance, and cultivating personal acquaintance among fellow-workers in the science, has been under consideration for some time, and the present year is believed to be an unusually favorable opportunity for the meeting, on account of the facility with which scientists from the eastern and southern sections can visit Indianapolis on their way to St. Louis, with no additional expense and no delay save the time spent at the congress. Microscopists desiring to attend should apply to the secretary of the committee for circulars giving further information, and should send notice of any important business to be offered for consideration, and titles of papers proposed to be read, accompanied by a copy of the papers or by abstracts of the same, to the secretary of the committee at 1 This department is edited by Dr. R. H. WARD, Troy, N. Y.

least two weeks before the time of the meeting, in order that a correct programme may be prepared.

The invitation to the congress at Indianapolis was, on motion, accepted, and it was resolved that members finding themselves able to attend should give early notice to that effect to the secretary of the committee, at No. 413 N. East street, Indianapolis.

Mr. Joseph McKay gave a demonstration of Prof. H. L. Smith's method of dry mounting by means of a background of wax and a curtain-ring cell, showing the facility and elegance with which this method may be carried out.

Rev. A. B. Hervey described a New Method of Fluid Mounting which he had recently devised. In his study of the algae and lichens he had been troubled, as others have been, by the difficulty of permanently mounting specimens while studying them, without waste of time or change of arrangements. Most of the methods of mounting either ruin such objects entirely or else require considerable time, care, and special appliances that are troublesome to a busy student; and therefore instructive specimens are often neglected and lost. The objects may be transferred from water to Farrant's solution of gum and glycerine and mounted without delay, but the structure is not well preserved and air bubbles are likely to be obstinately present. The objects show best in distilled water, sea water, camphor water, etc.; and to mount them instantly and with uniform success he prepares cells of the gum and glycerine solution put on by means of the turn table in the usual way. Having made cells of the required depth, and laid them aside until thoroughly dry, the inner half of the width of the cell is varnished on the turn table with gold size, which is also allowed time to dry perfectly. Objects in water are arranged and covered in these cells with ease, and are ready after lying aside for a time varying from a few minutes to a few hours, to receive a coat of gold size or other varnish, the fluid that exudes from the cell in pressing down the cover glass having dissolved enough of the gum cell to hold the cover in position. It has not been found that the cell is too much affected by the fluid; but if it should be so the cell could be made of the usual cements, insoluble in water, and then coated with a thin layer of gum.

Mr. C. E. Hanaman demonstrated the use of the Nachét camera lucida, and quoted opinions from discussions at the Queckett Club to confirm its superior facility of use as compared with the other forms of camera.

Dr. Ward presented the New Self-centering Turn-table recently contrived by W. H. Bulloch, of Chicago, and remarked that this table seemed to combine all the really radical improvements that have been made in the turn-table up to the present time. The early tables were more or less satisfactory varieties of the original Shadbolt form, and were arranged to be whirled in a variety of