368 
PROFESSOR F. D. ADAMS AND DR. J. T. NICOLSON 
having some device standing out from its surface, was placed face upwards. On this 
was laid a circular disc of marble. Oil was then poured in to fill up all vacant spaces. 
The piston was then inserted, and by it pressure was brought to bear upon the 
marble, which pressure was gradually increased to 13.000 atmospheres. The oil, 
which could escape only through the very narrow space between the piston and the 
casting, served to maintain a considerable pressure on all parts of the apparatus and 
the marble to which it had access, while the raised portions of the die coming in 
contact with the marble were pressed against it with great force. It was found that 
a well-marked, although not very perfect, reproduction of the device upon the die was 
impressed upon the marble. He also placed a small marble sphere in a stout copper 
box, filling the space between the marble and the sides of the box with alum or 
sulphur, poured in while molten. A heavy cover was then placed upon the box, and 
the whole was squeezed down to a fraction of its former height by means of a powerful 
press. After compression the alum or sulphur was dissolved away, setting free the 
enclosed marble, which was found to have been considerably flattened in a direction 
at right angles to the pressure. # In another experiment he enclosed a marble 
cylinder in an iron tube, and having filled the intervening space with water, bent the 
whole transversely by the application of a high pressure. When the tube was sawn 
open, the marble was found to have acted “ like a plastic body/' without having 
“ altered its original characters.’ t In connection with these experiments, however, 
it must be mentioned that the marble, as will be seen later, could not have preserved 
its original character in all resjjects, although it retained its coherence, and Peyek 
in referring to the experiment says that the marble was crushed, and 4i nur massig 
zementirt/'l It is doubtful in the case of the deformed spheres of the first-mentioned 
experiment in how far the deformation obtained is traceable to plastic flow. Three of 
these deformed spheres were presented by Professor Kick to the University of 
Zurich, and are preserved in the Geological Museum of the University. Two of them, 
each about 2 centims. in diameter, certainly show a decided flattening, such as might 
be produced by plastic flow; but the third, which is considerably larger, and is so 
flattened that the length of the smallest diameter is about two-thirds that of the 
greatest, shows in its surface a series of fine cracks crossing obliquely, as if the rock 
had undergone some sort of complicated shearing, and where cracked across in one 
place the interior is seen to present a shelly structure, resembling in appearance the 
successive coats of an onion. 
Daubree§ also obtained some very interesting results bearing on this subject, in 
* “ Die Principien der mechanischen Technologie und die Festigkeitslehre,” ‘ Zeit. des Vereines 
Deutscher Ingenieure,’ Bd. 36, p. 919, 1892. 
t ‘ Das Gesetz der proportionalen Widerstaiide,’ p. 76. 
i 1 Theoretische Geologie,’ p. 444. 
§ “Reeherches experimentales sur le role possible des gaz a halites temperatures,” ‘Bull, de la Societe 
Geologique de France,’ 3e serie, tome 19, p. 340. 
