In the July number of the MONTHLY Dr. H. C. Bolton gave an account of the radio-active substances which have been found in pitchblende, the chief ore of uranium. The subject continues to excite the interest of both chemists and physicists, though just at present the largest amount of work is being done by the chemists, to whom the question is of extraordinary interest as to whether these substances are or are not real chemical elements. Béla von Lengyel, of Budapest, as Dr. Bolton explained, has attacked the problem from the synthetic side, and by fusing inactive barium nitrate with uranium nitrate, he has obtained a barium sulphate which has more or less radio-activity. From this he concludes it is probable that the radio-activity is due rather to a peculiar state of the barium than to a new chemical element. On the other hand, Becquerel has in a somewhat analogous way mixed inactive barium chlorid with uranium chlorid, and from the solution has obtained likewise a radio-active barium. But he finds that the increased activity in the barium salt is attended by a corresponding decrease in the radio-activity of the uranium. Hence it cannot be settled from these experiments whether the uranium salts possess a radio-activity of their own, which can by certain methods be communicated to barium salts, or whether the radio-activity is due to an impurity in the uranium which has thus far eluded isolation. * * * * * The director of the Blue Hill Meteorological Observatory, Mr. A. Lawrence Rotch, writes to ‘Science’ that the highest previous kite-flight was exceeded on July 19, when, by means of six kites attached at intervals to four and three-quarters miles of steel wire, the meteorograph was lifted 15,170 feet above Blue Hill, or 15,800 feet above the neighboring ocean. At the time that the temperature was 78° near the ground, it was about 30° at the highest point reached, the air being very dry and the wind blowing from the northwest with a velocity of twenty-six miles an hour. The altitude reached in this flight probably exceeds the greatest height at which meteorological observations have been made with a balloon in America. The highest observations that have been published were made by the late Professor Hazen, of the Weather Bureau, in an ascent from St. Louis, June 17, 1887, to a height of 15,400 feet. * * * * *