104 ABSTRACTS 



time at the rate of 15,000 barrels daily. It is no slight task to keep 

 one of these deep-well records with the necessary care, since to be 

 reliable a sample of the drillings must be washed, dried, and properly 

 labeled every time the tools are withdrawn from the well. Then, too, 

 as all rope measurements are not reliable to within ten to fifteen feet, 

 steel-line measurements must be taken frequently, all of which was 

 done in the present instance, so that the 2342 feet of strata, penetrated 

 from eighty-six feet above the Pittsburg coal down to seven feet under 

 the base of the Fifth Oil Sand, is represented by 570 samples of drill- 

 ings and fifty-five steel-line measurements, from which data a very 

 complete account of the rocks from the Pittsburg coal down nearly to 

 the top of the Chemung may be obtained, for all of which geologists 

 are certainly under great obligations to Mr. Vandergrift. The writer 

 will publish the log of the well, as noted by the party keeping the 

 same, and also a condensed record in more strictly geological terms. 



A Note on the ''Plasticity'' of Glacial Ice. By Israel C. Russell. 



Experiments by McConnell, Kidd, and Miigge have demonstrated 

 that a bar of ice cut from a single crystal, with the optic axis perpen- 

 dicular to two of the side faces, when subjected to a bending stress, 

 will bend freely in the plane of the optic axis, but not at all in a plane 

 perpendicular to that axis. In the bent crystals the optic axis in any 

 part is normal to the bent face in that part. As stated by McConnell, 

 the crystals behave as if they were composed of an infinite number of 

 thin sheets of paper, normal to their optic axis, and attached to each 

 other by some viscous substance which allowed one to slide over the 

 next with great difficulty. The greatest freedom of movement was 

 found to occur when the ice experimented on was near the melting 

 point, and became less and less with a decrease of temperature. In 

 certain of the experiments referred to the freedom of movement at 

 — 2° C. was twice as great as at — 10° C. When thin sections of gla- 

 cial ice are examined by means of polarized light, as shown by Deeley, 

 Fletcher, and others, it is seen that the granules of which it is com- 

 posed are fragments of ice crystals, or perhaps imperfectly formed 

 crystals which interlock one with another so as to resemble the struc- 

 ture of coarsely crystalline dolomite. 



The optic axes of the granules are without definite arrangement, 

 but have all directions. Pressure brought to bear on such granular 

 ice in a definite direction would cause movement in the crystal frag- 



