Jan., iqii. Annual Report of the Director. 33 



all the sash screws and in place of screws of ordinary type the sash were 

 all fitted with bronzed screws with an interrupted slot of the standard 

 Museum pattern. Both the appearance and safety of the cases have 

 been much improved by this change. In the same Hall considerable 

 rearrangement of the collections has also been made in order to permit 

 the introduction of new material. This material consisted chiefly of 

 series of the rare earths which are coming into increased notice and for 

 which inquiries are often made by visitors. In order to secure the 

 space needed, considerable selection was made among the iron ores, 

 especially those of Lake Superior, so that those of essentially similar 

 appearance might be represented by the smallest possible number of 

 specimens. It was thus found possible to reduce the space which this 

 collection occupied without lessening the educational value of the 

 series. In the readjustment selection was also made so that the series 

 illustrating the lesser metals, such as mercury, tin, aluminum, nickel, 

 cobalt, etc., should indicate as nearly as possible by their extent the 

 relative importance of these metals. Thus the symmetry of the collec- 

 tions has been much improved and space gained for addition of new 

 material. These changes have, however, been restricted to specimens 

 in the wall cases along the south and southeast walls. In one of the floor 

 cases the group of specimens presented by the Utah Copper Company 

 has been installed, space having been secured by the withdrawal of some 

 of the specimens of Lake Superior copper. The new material consists 

 of ^wo large specimens illustrating oxidized and sulphide ore and a 

 series of crushed specimens representing the several stages by which a 

 rich concentrate is obtained from the original low-grade material A 

 large specimen of martite from Utah has been installed in a floor 

 case, supplementing other large specimens of iron ores. Supplementing 

 this exhibit a series of models illustrating the modern blast furnace and 

 its evolution is in preparation for exhibition in this Hall. The discon- 

 tinuance of chemical work in the Museum building having been deemed 

 advisable, the portion of Hall 75 previously used as a chemical lab- 

 oratory has been dismantled and the hood, desks, and apparatus pre- 

 viously in use there have been removed to a building on Jefferson 

 Avenue where partial accommodations have been secured. In the ab- 

 sence of sufficient accommodations the Executive Council of Armour 

 j Institute very generously placed the facilities of the chemical lab- 

 l oratories of that institution at the disposal of the Department and an 

 appreciated use has from time to time been made of these facilities. In 

 j the paleontological laboratory the following vertebrate material has 

 been prepared during the year: One skull of Brontothcrium ramosum 



