Abstract :
A PAPER under the above title was presented by the writer at the Pacific Coast Convention of the Institute in the summer of 1922, and was printed on page 740, Vol. XLI, 1922 Transactions of the Institute. This article and the included curves comparing the frequency of failure of the various disks of the assembly with the voltage gradient curve has been of sufficient interest to engineers connected with the high-tension insulator industry for the author to be requested to bring his investigation up to date by including the results of insulator tests of 1923 and 1924.