IW. F. D. A. lams find Dr. J. T. Xi 



into the tul>o when cold. The tube was then expanded by heat- 

 o as to allow the marble to pass completely into it and leave 

 sil unit 1'25 inch of the tube free at either end. On allowing the tube 

 to cool, a perfect contact between the iron and the marble was obtained. 

 In some experiments the tube was subsequently turned down, so as to 

 be somewhiit thinner immediately around the marble. Into either end 

 of the tube, containing the column, an accurately fitting steel plug or 

 piston was then inserted, and by means of these the pressure wa> 

 applied. The high pressure required was obtained by means of a 

 powerful press, especially constructed for the purpose, consisting of a 

 double hydraulic " intenbifier," the water pressure being in the first 

 instance obtained from the city mains. By means of this machine, 

 pressures up to 13,000 atmospheres could be exerted on the columns 

 having a diameter of 0*8 inch, and the pressures could be readily 

 regulated and maintained at a constant value for months at a time, if 

 required. 



It having been ascertained that the columns of the marble 1 inch in 

 diameter and 1 inch in height crushed at a pressure of from 11,430 

 to 12,026 Ibs. to the square inch, the column enclosed in its 

 wrought-iron tube, in the manner above described, was placed in the 

 machine and the pressure applied gradually, the exterior diameter of 

 the tube being accurately measured at frequent intervals. No effect 

 was noticeable until a pressure upon the marble, varying of course with 

 the thickness of the enclosing tube, but generally about 18,000 Ibs. 

 to the square inch, was reached ; when the tube was found to slowly 

 bulge, the bulge being symmetrical and confined to that portion of the 

 tube surrounding the marble. The distension was allowed to increase 

 until the tube showed signs of rupture, when the pressure was 

 removed and the experiment concluded. The conditions under 

 which the marble was submitted to pressure were four in number : 



1. At the ordinary temperature in the absence of moisture. (Cold 



dry crush.) 



2. At 300 C. in the absence of moisture. (Hot dry crush.) 



3. At 400 C. in the absence of moisture. (Hot dry crush.) 



4. At 300 C. in the presence of moisture. (Hot wet crush.) 



Eight experiments were made on marble columns at the ordinary 

 temperature, in the absence of moisture, the rate at which the pressure 

 was applied differing in different cases, and the consequent deformation 

 being in some cases very slow and in others more rapid, the time 

 occupied by the experiment being from ten minutes to sixty-four days. 

 The amount of deformation was not in all cases equal, as some of the 

 tubes showed signs of rupture sooner than others. On the comple- 

 tion of the experiment the tube was slit through longitudinally by 

 means of a narrow cutter in a milling machine, along two lines 



