Balloon ascensions are quietly but frequently used by scientific men for the purpose of studying the upper parts of the atmosphere. Russian savants have lately paid especial attention to this work, but have been prevented from extending their examinations to any great height. Prof. Mendeleef of St. Petersburg now undertakes to accomplish this also, and devotes the profits of two books published by him to the construction of a balloon. This is to have a capacity of two or three thousand cubic yards, and will be filled by means arranged by him. France also pursues this path of investigation with great vigor. Count Bathyani recently took up a radiometer to a height of about a mile. At the earth it made in the shade thirty-five revolutions per minute. At the height of 5,000 feet it made sixty-four revolutions, also in the shade. In the sun, 2,300 feet above the earth, it made fifty-four revolutions. Count Bathyani also took up an ethereal apparatus for the purpose of condensing water vapor at various heights, in order to collect the microscopic particles floating in the air. This line of investigation will be continued by means of an apparatus filled with methylic ether. This will give a temperature of -20 deg. C., or -15 deg. Fahr. The moisture will condense as ice which will be scraped off the vessels. All the solid particles floating in the immediate neighborhood of the apparatus will also be obtained. THE LEAD PRODUCT. The mining of lead is a business in which Americans are successfully using the remarkable resources of this country. In 1866 the amount made here was only 14,342 tons, while we imported 23,330 tons. In fact the importation has exceeded the home product ever since 1850 with the exception of one year--1860. This improper "balance of trade" was due to the system and intelligence with which foreign smelting works are conducted, and the ignorance which prevailed in our own country where the mining resources are really superior to those of Europe. But this state of things has changed with the foundation of mining schools and the spread of mining knowledge in this country. In 1873 the "balance" turned the other way. The importations have been since then 22,114, 17,674, 7,305, and 4,685 tons; while the home product shows a rise corresponding closely to this falling off, being for the same years, 37,983, 46,500, 53,250, 57,210 tons. In fact we export as much as we import, for the 4,300 tons of pig lead imported is balanced by the quantity sent back to Europe in the form of bullets. This change in the business is traceable to the fact that refining has been found to pay in America, and our lead is thus in request by the white paint makers. For years our product lay under a stigma, and it was said that it was not suited to the manufacture of the best lead. This evident error has been corrected; the refined virgin lead of Missouri and Illinois makes the best white lead, and the mining of the metal is not likely to