LXXXIX. On the application of alternating currents to the calibration of capacity-boxes, and to the comparison of capacities and inductances
W. Stroud, J. H. Oates · The London Edinburgh and Dublin Philosophical Magazine and Journal of Science · 1903
0~ the Calibration of Capaclty.boxes.707 was made tight by a mercury seal.The tube, with the radium beside it, was placed in a large box lined with lead.In making the experiments the tube was sealed to a threefall Sprengel pump and exhausted, being gently warmed at intervals during the process.When the McLeod gauge showed a high vacuum had been obtained dry air was slowly admitted through a series of drying-tubes until atmospheric pressure was reached.The glass tube giving connexion with the external air was then sealed off and observations of the potential-difference were commenced.The pump was ~tarted and kept workino'~, for about six hours, readings of the electrometer being taken from time to time.When the highest vacuum attainable had been reached dry air was once more admitted to the testing-vess@ but no alteration in the deflexion co,,ld be perceived.The series of operations was repeated with the same result.It was estimated that an alteration of 5 per cent.could be detected.In conclusion we must express our great indebtedness to Lord Kelvin and Dr. J. T.