fairly good mortar, without calcination or other previous preparation. The lignite found near the Colorado line makes a valuable domestic fuel. Natural gas, oil, zinc and lead have been discovered in south-east Kansas and have given that section an extraordinary growth and prosperity. Indications of gas were found about the time of the Civil War, but only in the early 'seventies were they recognized as unmistakable, and they were not successfully developed until the 'eighties. Iola, in Allen county, is the centre of the field, and the gas yields heat, light, and a cheap fuel for smelters, cement-works and other manufacturing plants throughout a large region. The pools lie from 400 to 950 ft. below the surface; some wells have been drilled 1500 ft. deep. The value of the natural gas produced in the state was $15,873 in 1889, $2,261,836 in 1905 and $7,691,587 in 1908, when there were 1917 producing wells, and Kansas ranked fourth of the states of the United States in the value of the natural gas product, being surpassed by Pennsylvania, West Virginia and Ohio. Petroleum was discovered about 1865 in Miami and Bourbon counties, and about 1892 at Neodesha, Wilson county. There was only slight commercial exploitation before 1900. The production increased from 74,714 barrels in that year to 4,250,779 in 1904; in 1908 it was 1,801,781 barrels. Chanute has been the most active centre of production. The field was prospected here in the 'nineties, but developed only after 1900. In 1877 an immense deposit of lead was discovered on land now within the limits of Galena. Rich zinc blendes were at first thrown away among the by-products of the lead mines. After the discovery of their true nature there was a slow development, and at the end of the century a notable boom in the fields. From 1876 to 1897 the total value of the output of the Galena field was between $25,000,000 and $26,000,000; but at present Kansas is far more important as a smelter than as a miner of zinc and lead, and in 1906 58% of all spelter produced in the United States came from smelters in Kansas. In 1908 the mines' output was 2293 tons of lead valued at $192,612 and 8628 tons of zinc valued at $811,032. Pottery, fire, ochre and brick clays are abundant, the first two mainly in the eastern part of the state. Coffeyville has large vitrified brick interests. In 1908 the total value of all the mineral products (incompletely reported) of Kansas was $26,162,213.