136 Field Museum of Natural History — Reports, Vol. III. 



These columns are each made up of four angle-beams joined together 

 by means of solid "fillers," and all firmly riveted with flush-head 

 rivets. They vary in size according to the load which they are 

 designed to carry. Each column is braced at its base by four gussets, 

 which are bolted respectively to the four intersecting I-beams, and 

 riveted between the angle-irons of the column in place of the "filler." 

 The four vertical columns support a longitudinal T-beam, firmly 

 bolted to their upper ends. The angles formed by the two are tied 

 by short diagonal braces. The T-beam forms the support of the 

 vertebral column, and is bent so as to conform closely to its inferior 

 outline. It is tapered towards the rear end, so that its size is reduced 

 in proportion to the load it is intended to receive. The individual 

 bones are fastened to this framework by forgings of wrought iron. 

 These supports are bent to conform closely to the surface of the 

 bone in order to be as inconspicuous as possible. They attach to the 

 bones, in most instances, by being bent so as to clasp them firmly. 

 Work on the mount has progressed so that the greater part of the 

 vertebral column is now in place. Many of the bones were so dis- 

 torted as to require considerable modification before they could be 

 fitted into their respective positions in the skeleton. A missing 

 femur and ilium have been supplied by modeling them in plaster 

 from the corresponding bones of the opposite side, and several 

 ribs and chevrons have been restored as a whole or in part. As it 

 was found necessary to perform a large part of the shaping of the 

 steel contiguous to the skeleton, a gas forge was placed upon the west 

 porch of Hall 35, so as to provide facilities for heating the individual 

 steel pieces. A temporary sheet-iron shed erected over this permits 

 continuance of the work during the winter months. In the cases 

 left vacant in Hall 36 by removal of portions of the dinosaur skeleton 

 for mounting, there have been installed a sacrum and seven dorsal 

 vertebrae of Brachiosaurus, and some minor specimens. To the 

 series on exhibition in Hall 59, have been added during the year two 

 skulls of Promerycochcerus and single skulls of Merycochcerus, Hyasn- 

 odon, Hyracodon, Procamelus and Amphicyon. In Hall 61 a superb 

 complete skeleton of Promerycochcerus, worked out during the year, 

 has been placed upon exhibition. Some minor rearrangements of 

 exhibited series have been made in connection with these additions. 

 To the hall of meteorites, Hall 62, a wall case has been added, to 

 provide for increase in the collection, and new specimens received 

 have been installed. Additions to the systematic mineral collection, 



