LEAD 



3356 



LEAD POISONING 



paints; red lead, a compound of lead and oxy- 

 gen, is also used as a paint; litharge, another 

 oxide of lead, is used in making plate glass and 

 glass for lenses. Lead chromate is used as a 

 pigment under the name of chrome yellow. 

 It is of interest to note that although white 

 lead and red lead are lead compounds, black 

 lead is not lead at all, but a form of carbon 

 (which see). 



The United States produces more lead than 

 any other country. The leading states, in the 

 order of their production, are Missouri, Idaho, 

 Utah and Colorado. Canada is rapidly devel- 

 oping a lead industry of importance, and, to 



.Missouri 



i Colorado 

 V 40 



Arizona 

 68 



OKIahoma 



figures Represent Thousands of Short Tons 



PRINCIPAL UNITED STATES SOURCES 



encourage the operation of silver-lead smelt- 

 ers, the government pays a bounty of fifty 

 cents per ton on all the lead produced. The 

 annual output is about 20,000 short tons. 



Lead Tree. If a rod of zinc is suspended in 

 a solution of lead acetate, lead will precipitate 

 on it in branching crystals, forming what is 

 fancifully called a lead tree. J.F.S. 



Consult Kemp's Ore Deposits of the United 

 States and Canada; Hoffman's Metallurgy of 

 Lead. 



LEAD, leed, S. D., a city famous for its 

 gold mines, which are among the largest in 

 the world. It is situated in Lawrence County, 

 about midway between the northern and 

 southern borders of the state, and thirty miles 

 east of the Wyoming state line. Pierre, the 

 capital, is 250 miles east. The Chicago, Bur- 

 lington & Quincy and the Chicago & North 

 Western railways serve the city. Lead was set- 

 tled in 1877; it was incorporated as a city in 

 1890, and it adopted the commission form of 

 government in 1912. The word Lead is a 

 miner's term, which denotes the discovery of a 

 lode. About thirty-five per cent of the popula- 

 tion is comprised of English, Italians, Austrians 

 and Finns. Population, 8,392 in 1910; it had 

 increased to 9,763 by 1916 (Federal estimate). 



By the single industry of gold mining, Lead 

 has been converted from a vast mining camp 

 into a modern mining city, with well-lighted, 

 well-paved streets and handsome buildings. Its 

 setting is in the heart of the Black Hills, in 

 the midst of some of the wildest scenery of the 



West. Such an abundance of pure sparkling 

 water is furnished by the mountain streams 

 that it is available for public and for private 

 use. Here is located one mining company 

 employing over 2,200 men; about 5,500 are 

 employed by the other mining companies. 

 The city has a Federal building, constructed in 

 1910 at a cost of $90,000; a high school in 

 which domestic science, domestic art, business 

 and technical courses are provided; the Hearst 

 Free Library, the gift of Mrs. Phoebe Hearst; 

 a business school, and a kindergarten. An 

 institution worthy of mention is the Recreation 

 building, which contains an auditorium, a gym- 

 nasium, a swimming pool, bowling alleys and 

 billiard rooms; it was erected by one of the 

 mining companies for its employees and cost 

 a quarter of a million dollars. Besides the 

 mining industry, the city has machine shops, 

 mining-tool works and one of the most exten- 

 sive cyanide plants in the world. E.C.T. 



LEAD, SOUNDING, upon which sailors once 

 depended for determining the depth of water, 

 is a tapered leaden cylinder attached to a 

 lead-line of rope or wire. Since shores and 

 harbors have been charted, and instruments 

 have been invented which will accurately meas- 

 ure depths from ships in motion, the lead is 

 seldom employed in navigation, though still 

 used in explorations of shallow waters (see 

 SOUNDING). The underside of a lead is hol- 

 low and contains tallow, that it may bring up 

 ooze or mud to prove that it has touched the 

 sea bottom. The hand lead, for use in less 

 than twenty fathoms (120 feet) of water, 

 weighs from five to fourteen pounds. 



LEAD POISONING, a serious disease caused 

 by lead entering the system. It usually af- 

 fects painters and persons employed in white- 

 lead factories. The most common result is 

 lead cplic, or painter's colic. The trouble may 

 also attack other persons who drink water which 

 has pulsed through new lead pipes; from eat- 

 ing candy which has been colored with chro- 

 mate, chloride or carbonate of lead; or by 

 living in rooms which have been freshly 

 painted with lead colors. Sometimes it results 

 in kidney disease, muscular palsy, epilepsy or 

 serious brain trouble. Lead poisoning is first 

 detected by a change of color in the counte- 

 nance of the sufferer, which turns to a sallow, 

 earthy hue. The skin becomes dry and harsh; 

 the digestion becomes disordered, and a sweet- 

 ish, metallic taste is felt in the mouth. The 

 margin of the gums turns blue or violet, due to 

 the formation of a sulphite of lead. 



