Characteristic equations of tungsten filament lamps and their application in heterochromatic photometry

• Publisher: Elsevier Science
• Year: 1915
• Tongue: English
• Weight: 134 KB
• Volume: 179
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(15)91159-6

✦ Synopsis

barometer at the time. This result does not depend upon the rate at which pressure is changing.

From experiments made at Kew Observatory with two marine barometers it is shown that, in fact, the effect of lag is much greater than according to Stokes's formula, and that it depends partly upon the rate at which the pressure is changing. Thus the ratio of the observed to the calculated lagging-time varies from IO or 12 when the rate of pressure-change per hour is 0.0058 inch to 5 or 6 when the rate is 0.0242 inch per hour. On the other hand, readings made at sea on board the steamship Hesperian with the same two barometers appear to indicate that on board ship the effect of lag is exceedingly small, even smaller than it should be according to Stokes's formula.