Another important invention was made in 1792 in America by the widow of General Nathaniel Green. It was the so-called cotton gin by which the difficult work to separate the seed from the lint was greatly simplified. To pick the seed from one pound of cotton had been formerly considered a good day’s work. With the aid of the cotton gin, which consists of a series of saws revolving between the interstices of an iron bed upon which the cotton is placed so as to be drawn through whilst the seeds are left behind, several hundred pounds of cotton can be cleaned in the same time. This invention stimulated enormously the cultivation of cotton and the manufacture of cotton goods in America. In the South, where so far cotton had been produced only in small quantities, it now became the main product. While in 1792 the quantity exported from the United States was 138,324 pounds, it increased by the year 1800 to nearly 18,000,000 pounds. In the North it led to the establishment of cotton mills and factories on a large scale. As only few countries have taken the trouble to prepare statistics about inventions made by women it is impossible to give reliable facts about what women have contributed to human culture in this line. Their most intensive activity has been observed in the United States, especially since with the founding of woman’s colleges and the opening of the universities, the education of the female sex became a more careful and broader one. The U. S. Patent Office at Washington, D. C., has published “Lists of Women Inventors,” in three volumes, covering the period from 1790 to March 1, 1895. From these lists it appears that till 1849 only 32 inventions by women have been registered at the Patent Office. This number increased to 290 during the period from 1850 to 1870; during 1870–1890 to 2568, and up to 1910 to 7942. These numbers prove that with the increase of woman’s knowledge and with the closer contact with modern industrial life her inventive spirit has likewise developed. Also the inventions became more manifold. While prior to 1850 they were almost exclusively confined to dress and household, they now cover all fields of human activity. This fact became most evident during the terrible years of the World War. Some time ago the “Women Lawyer Journal” reported that of all the many inventions registered since 1914, fifty per cent. have been entered by women. Among these inventions have been such for the better protection of soldiers and aeronauts as well as for the greater comfort of the wounded and crippled. Other inventions meant improvement in wireless telegraphy, gas masks, submarine boats and hundreds of other objects. [Illustration] EMINENT FEMALE SCIENTISTS.