NATURAL PHILOSOPHY. 177 



their adhesive power. Still further to elucidate the subject, cubes of 

 exactly one inch were carefully prepared and loaded -\vith -weights till they 

 were crushed. The first cube, solidified under a pressure of 6,421 lb., 

 was crushed with 213 lb. Tin was then operated on, a quantity of pure 

 tin b3mg melted and then allowed to solidify, first at the pressure of the 

 atmosphere, and afterwards at a pressure of 908 lb. on the square inch. 

 The same quantity taken from the same ingot was subsequently sub- 

 mitted to a pressure of 5,698 lb. on the square inch. The bars, after 

 being solidified and allowed to cool for upwards of fourteen hours, 

 were subjected to the visual tests of tensile strains. From these experi- 

 ment , there was derived, as nearly as possible, the same law or meas- 

 ure of strength in regard to the effects of pressure as obtained from the 

 experiments on spermaceti ; for, with the same pressures of 908 lb. and 

 5,698 lb. upon the square inch, the breaking weights were 4,053 lb. and 

 5,737 lb., or in the ratio of 1 to .706, being an increase of nearly one-third 

 on the crystallized metal when solidified under about six times the press- 

 ure. From these facts, Mr. Fairbairn observed, it is evident that the power 

 of bodies to resist strain is greatly increased when solidified under press- 

 ure ; and he said he considered it highly probable that the time is not far 

 distant when the resisting powers of metals, as well as their densities, may 

 be increased to such an extent as to insure not only greater security, but 

 greater economy by solidification under pressure. He said he was borne 

 out in these views by the fact that the specific gravities of the bodies 

 experimented on were increased in a given ratio to the pressure. Sperma- 

 ceti solidified under a pressure of 908 lb. on the square inch, had a specific 

 gravity of 0.94859 ; whilst that solidified under a pressure of 5,698 lb. 

 had its specific gravity increased to 0.9549.5. The specific gravity of tin 

 solidified under a pressure of 903 lb. was 7.3063 ; and that solidified under 

 a pressure of 5,693 lb. was 7.3154, which gave .0091 as the increased 

 density from pressure. There are further experiments in progress to 

 determine the law that governs this increase of specific gravity, and to 

 determine the conducting powers of bodies solidified under severe pressure. 

 Experiments have also been made on such substances as clay, charcoal and 

 different kinds of timber. From the experiments on powdered dry clay, it 

 appeared that a bar of that substance 3k inches long and 1^ inches diame- 

 ter, after being hammered into the cylinder so as to become slightly consoli- 

 dated, was reduced in bulk with a pressure of 9,940 ib. on the square 

 inch to 2. 958; -with a pressure of 54,580 lb. to 2.3 ; with 76,084 ib. to 

 2.28S ; and with a pressure of 97,588 lb. to 2.195 inches. 



INVESTIGATION INTO THE THEORY OF THE PENDULUM. 



An important investigation of the theory of the pendulum, taking into 



account the rotation of the earth, has recently been published by the 



Physical Society of Dantzic, being a memoir on the subject by M. 



Hansen, which has been honored with the prize of the Society, The 



8* 



