The organizing committees of the Congresses of Aëronautics and Meteorology--these being cognate subjects--of the Exposition of 1900 have decided to hold the meetings of these bodies in such a manner that all members can attend the sessions of both. The programme arranged for the Aëronautical Congress contemplates the discussion, under aspects which are set forth in detail, of “problems” relating to free balloons, their management and use; captive balloons, steerable balloons, and aviation; and the scientific applications of balloon observations to problems in astronomy, meteorology, and physiology; also of their use for purposes of reconnoissance and topographical surveys, and of photography from balloons. In a different order of ideas, the congress may occupy itself with questions of legislation and international law which concern aëronauts in times of peace and of war. * * * * * Three State catalogues of Ohio plants have heretofore been issued. The first, by J. S. Newberry, was published in the State Agricultural Report in 1859; the second, by H. C. Beardslee, was published in 1874, and was reprinted in the Agricultural Report for 1879; and the third, by W. A. Kellerman and W. C. Werner, was included in the State Geological Report for 1893. This work contains a bibliography, and gives the names of the first known collectors of the less common species. A fourth catalogue, consisting of a checklist of the _Pteridophytes_ and _Spermophytes_, recently published by Prof. W. A. Kellerman, contains the species and varieties numbered serially, as in the State Herbarium of nearly ten thousand sheets, with the sequence of groups as by Engler and Prantl, and the nomenclature as used by Britton and Brown. NOTES. The committee of the St. Petersburg Astronomical Society for the revision of the Russian calendar, to make it agree with the Gregorian, has found it necessary to move slowly. The festivals prove a formidable obstacle to the desired reform, and the people will have to be prepared for the change before it can be instituted. The plan now is to use both dates, Russian and Gregorian, together till the new style can be made familiar, and it is proposed to make the double use compulsory on private as well as on public documents and papers. * * * * * A steamboat company is placing its little vessels on the canals of Venice, and the gondolas, which were one of the charms of the city to travelers, are destined to disappear--unless a few may be reserved to gratify the curiosity of tourists. * * * * *