528 



MINERAL WOOL. 



MINNESOTA. 



by a small majority over all. The Republicans 

 also gained control of the City Council. The 

 Democrats had just secured the State govern- 

 ment for the first time in thirty years, and the 

 Detroit split was of the deepest moment to the 

 State at large, inasmuch as it tended to jeopard 

 the supremacy of the party. 



MINERAL WOOL OR MINERAL COT- 

 TON, a filamentous substance produced from 

 furnace slag, resembling wool or cotton in ap- 

 pearance, useful, by reason of its low conducting 

 power, as packing to prevent the freezing of 

 water pipes and the cooling of steam pipes -and 

 boilers, and also to keep out dampness, and as a 

 protection against fire, it being incombustible. 

 The spray from the slag emitted from the vol^ 

 cano of Kilauea is blown by the wind into 

 glassy fibers called the " Hair of Pele," which 

 have the same nature and character as artificial 

 slag wool, the process of manufacturing which 

 was invented by John Player, and was patented 

 at the United States Patent Office on May 31, 

 1870, and the patent was renewed on Feb. 1, 

 1876. The liquid slag issuing from a tap in the 

 pig-iron furnace is conducted through a runnel 

 formed by coal ashes on iron plates to the point 

 where it is to be blown and allowed to fall in a 

 stream about 1 centimetre thick for a distance 

 of 15 centimetres, where it is met by a powerful 

 blast of steam, which separates it into long fila- 

 ments, as fine as hair and as white as wool, in 

 which form it drops into the room constructed 

 for its reception. This chamber is about 100 

 feet from the place where the jet of steam strikes 

 the falling stream of slag. In some furnaces 

 the slag is brought on cars in a molten state to 

 the place where it is tapped and blown into the 

 wool house. In the Krupp works at Essen, 

 Germany, a blast of cold air is used, instead of a 

 jet of steam, to blow the slag into filaments. 

 Ordinarily, pellets of slag of various sizes are 

 found mingled with the wool-like mass. These 

 are larger drops of the slag that the blast fails to 

 divide thoroughly, and must be separated from 

 the product. A' process for preventing them 

 from falling into the chamber by means of a 

 second blast of steam or air striking the blown 

 slag in its passage through the air transversely 

 from below was patented in Germany by A. D. 

 Elbers in 1877. The light wool, blown upward 

 by this second blast, falls into a basket, while 

 the heavier pellets and lumps are not deflected 

 from their original course. The long filaments 

 are broken up into short ones, and the substance 

 when ready for use has the appearance of wool 

 waste. The handling of mineral wool is attended 

 with some danger to the health, as the fine 

 threads penetrate the skin easily, producing in- 

 flammation, and the dust when inhaled irritates 

 the respiratory organs. In some furnaces, after 

 the manufacture of this by-product was intro- 

 duced it was afterward abandoned on account 

 of the injurious effects on the health of the 

 workmen. The uses of mineral wool are many. 

 As a packing and insulating material for steam 

 pipes, boilers, and cylinders it rivals asbestus. 

 It is used for the insulating layer in ice chests 

 and ice cellars. As a protection against damp 

 and for deadening sound it is used in board 

 floors, and also in roofing. To guard materials 

 exposed to damp and decay it finds various em- 



ployments. In making telegraph cables a pro- 

 tective layer of mineral wool is often used. 

 Another application is for the filtration of the 

 corrosive fluids used in the manufacture of paper 

 and pasteboard. For purposes of insulation 

 cotton or linen hose filled with mineral wool is 

 sometimes wrapped round the pipes or cylinders. 

 Another method is to mix it with dissolved 

 borax or alum, forming a soft mass like mortar 

 that hardens and adheres to the parts that are 

 to be insulated. 



MINNESOTA, a Western State, admitted to 

 the Union May 11, 1858 ; area, 83,365 square 

 miles. The population, according to each decen- 

 nial census since admission, was 172,023 in 1860 ; 

 439,706. in 1870; 780,773 in 1880: and 1,301,826 

 in 1890. Capital, St. Paul. 



Government. The following were the State 

 officers during the year : Governor, William R. 

 Merriam, Republican; Lieu tenant -Governor, 

 Gideon S. Ives ; Secretary of State, F. P. Brown ; 

 Auditor, Adolph Bierman ; Treasurer, Joseph 

 Bobleter ; Attorney-General, Moses E. Clapp ; 

 Superintendent of Public Instruction, D. L. 

 Kiehle ; Insurance Commissioner, C. P. Bailey ; 

 Railroad and Warehouse Commissioners, John 

 P. Williams, John L. Gibbs, George L. Becker; 

 Chief Justice of the Supreme Court, James Gil- 

 fillan ; Associate Justices, Loren W. Collins, 

 William Mitchell, Daniel A. Dickenson, and 

 Charles E. Vanderburgh. 



Finances. The estimated receipts and dis- 

 bursements for the fiscal years 1892 and 1893 are 

 as follow : 



RECAPITULATION. 



Receipts, 1892 $2,001,000 



Disbursements, 1892 1,524,500 



Surplus. 1 892 $476,500 



Receipts, 1893. $2,050,000 



Disbursements, 1893 1,766,500 



Surplus, 1893 $283,500 



Total surplus, 1892-'93. $760,000 



