. Carnegie Institution of Washington publication. 114 DISPLACEMENT INTERFEROMETRY APPLIED TO indicated by the little circles. The evidence is of the same nature, remember- ing that, quantitatively, the effect must depend on the rapidity of exhaustion, etc., which is kept low to avoid influencing the needle by a current of air directly and also to avoid large temperature decrements. There are thus two radiation effects, respectively positive and negative, which pass continuously into each other. One of these may be ascribed to the change of pressure into kinetic energy on the hotter side or sid
. Carnegie Institution of Washington publication. 114 DISPLACEMENT INTERFEROMETRY APPLIED TO indicated by the little circles. The evidence is of the same nature, remember- ing that, quantitatively, the effect must depend on the rapidity of exhaustion, etc., which is kept low to avoid influencing the needle by a current of air directly and also to avoid large temperature decrements. There are thus two radiation effects, respectively positive and negative, which pass continuously into each other. One of these may be ascribed to the change of pressure into kinetic energy on the hotter side or side of convection excess; i. e., there is pressure deficiency on the hotter side. The other, at higher vacua, is the radiometer effect, which is of opposite sign; i. e., there is pressure excess on the hotter side. Hence, between the two, somewhere near 65 cm. here, the two phenomena are in equilibrium and the effect of exhaustion is The investigation resulting in figure 144 was merely made for practical purposes and the deflections depend on many subsidiary details. It will be carried out under standard conditions presently. There is a correlative test for the effect of radiation, from without, on the needle in an exhausted case. To apply this, the case was exhausted to above 70 cm. and a ball heated to 60° or 70° placed outside. No discernible effect was produced, or, in other words, the effect of external radiation is now small. Consequently the drift of the needle must vanish and the triplets become static repetitions of each other. That this is the case the experiments of the next paragraph will show. It follows, also, that the resistance encountered by the needle is now referable to the viscosity of air and therefore possibly open to computation. At a later opportunity I returned to these interesting phenomena again, with the object of obtaining more definite results. The case of the needle was, as above, exhausted in steps of 10 cm. of mercury, successively and qui
Size: 2489px × 1004px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1900, bookyear1902
