The size and weight of the various parts are enormous.

The height of the head in the standing position reaches from 18 to 20 feet above the ground; the knee joint alone reaches 6 feet above the ground.

All the bones are massive; the pelvis, femur and skull are extremely heavy.

Experience with _Brontosaurus_ and with other large dinosaurs proves that it is impossible to design a metallic frame in the right pose in advance of assembling the parts.
Even a scale restoration model of the animal as a whole does not obviate the difficulty.
"Accordingly in preparing to mount _Tyrannosaurus_ for exhibition a new method has been adopted, namely, to _prepare a scale model of every bone in the skeleton_ and mount this small skeleton with flexible joints and parts so that all studies and experiments as to pose can be made with the models.
"This difficult and delicate undertaking was entrusted to Mr.Erwin Christman of the artistic staff of the Department of Vertebrate Palaeontology of the Museum, who has prepared two very exact models to a one-sixth scale, representing our two skeletons of _Tyrannosaurus rex_, which fortunately are of exactly the same size.

A series of three experiments by Mr.Christman on the pose of _Tyrannosaurus_, under the direction of the author and Curator Matthew, were not satisfactory.