377 378 379 380 381 382 383 384 385 386
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Observations of the doable displacement A. 1st Series. 1= 3*022 meters. 0 = 8*72 meters per second. A = double displacement; w = weight of observation.
If these results be reduced to what they would be if the tube were 10 Series. A. 1 *1858 2 *1838 3 *1800 The final weighted value of A for all observations is 4= *1840. From this, by substitution in the formula, we get x = *434 with a possible error of ±*02. The experiment was also tried with air moving with * a velocity of 25 meters per second. The displacement was about of a fringe; a quantity smaller than the probable error of — 1 observation. The value calculated from —— would be *0036. n It is apparent that these results are the same for a long or short tube, or for great or moderate velocities. The result was also found to be unaffected by changing the azimuth of the fringes to 90°, 180° or 270°. It seems extremely improbable that this could be the case if there were any serious constant error due to distortions, etc. Am. Jour. Sci.—Third Series, Vol. XXXI, No. 185.—May, 1886. 25 | The result of this work is therefore that the result announced by Fizeau is essentially correct; and that the luminiferous ether is entirely unaffected by the motion of ike matter which it permeates. Art. XXXYII.—Note on the Structure of Tempered Steel; by C. Barus and V. Strouhal. In view of the experiments oh the structure of steel by Dr. Hennig* now in progress in Professor Kohlrausch’s laboratory, we avail ourselves of the permission of the Director of the Geological Survey and of the Editors of this Journal, to insert a brief but typical example of our own results here. The complete paper will appear in Bulletin No. 35 of the Geological Survey, now in the hands of the Public Printer. The steel cylinder (length 6 cm., diameter 3 cm., weight 332 g.) to which the data refer was quenched glass-hard in the ordinary way. The consecutive cylindrical shells were then removed by galvanic solution, and the necessary measurements made to determine the density of each. Let A be the density (0° C.) of the consecutive cores. Let R, #, d, be the mean radius, thickness and density, respectively, of the consecutive shells. Then if the nth core be left after the removal of n shells, the table gives the digest in question. Shell or core No. A. 0 7-8337 0 7*7744 1 7-7734 2 7-7727 3 7*7742 4 7*7734 5 7*7750 6 7*7784 7 7*7813 8 7*7817 , 9 7*7841 10 7-7869 11 7*7894 12 7-7919 13 7-7911 14 7-7937 15 7-7979 16 7*7999 17 7-8017 18 7-8013 19 7-8027 20 7-8009 Warlington-Prague, *Wied. Ann., xxvii, 351, 1886.
April, 1886. Remarks. Before quenching. After quenching. Core perceptibly fileable. |