306 Field Museum of Natural History — Reports, Vol. IV. 



ment was made in order to improve sequences and permit of the introduc- 

 tion of new material. The new material was in part illustrative of the 

 uses of the metals and in part illustrative of ores and ore dressing. 

 Among new series so added may be mentioned that received from 

 Francis C. Nicholas illustrating the development of hematite from 

 pyrite and that from the Oliver Mining Company showing the con- 

 centration of iron ores by washing. New illustrations of uses of metals 

 added include series illustrating nickel plating, nickel steel, fracture and 

 color of different alloys of copper and zinc, and glass tinting and making. 

 The suites of six slabs of Georgia marbles, 13 slabs of Vermont marbles, 

 and three slabs of Canadian marbles received during the year were in- 

 stalled in their appropriate places in the marble collection in Hall 34, 

 some readjusting of space and specimens having been necessary for this 

 purpose. Some additions to the collections of abrasives, asbestos, and 

 vein formations were installed in Hall 31, and rearrangements of the 

 series already on exhibition were made for this purpose. Nine floor 

 cases of clays and sands have been installed in Hall 63. These 

 cases include six cases illustrating the classification of clays, one case 

 showing effects of different components on clays, one case of refractory 

 materials and one case showing uses of silica. A floor case of petroleum 

 products has also been installed in this hall and a wall case showing 

 varieties of soils in Hall 61. Two cases of graphite and asphalt in Hall 

 35 were rearranged in order to add a collection illustrating the uses of 

 graphite. A model of a coal mine, prepared for the uses of the Harris 

 Extension Fund, was installed in Hall 34 pending its use in the schools. 

 This model represents both the above-ground and underground equip- 

 ment of a large colliery, the features shown being typical of those gener- 

 ally employed. Above ground are shown in miniature a tipple and fan, 

 boiler house, machine shop and a village of miner's houses. In front of 

 these the ground is represented as cut away to a depth of 200 feet in 

 order to uncover the underground system of galleries and chambers. 

 Hoisting and air shafts connect the two portions. The underground 

 portion is worked on the panel-retreating system. Three panels are 

 shown; one worked out and caved in, one in active production, and one 

 just being opened. Other exhibits to the number of 20 have been pre- 

 pared for the use of the Harris Extension. These include series illustrat- 

 ing the origin of coal, coal plants of Illinois, invertebrate fossils, ores of 

 iron, ores of several metals, useful minerals, abrasives, glass manu- 

 facture, steel manufacture, graphite, asbestos, salt, etc. Floor cases 

 have been placed in Halls 35 and 59 for the installation of the Dolichor- 

 hinus mount and the skeleton of the fossil camel Oxydactylus. The 

 Dolichorhinus mount is the most nearly complete skeleton of this form 



