Adolf William Isenthal
Adolf William Isenthal (1867-1957)
Founder of Isenthal and Co.
1957 IEE Obituary.
With the death of Adolf William Isenthal on the 31st March 1957, in his ninetieth year, the electrical industry has lost one of its pioneer engineers. Educated at Munich, Hanover and Nuremberg, he was apprenticed from 1887 to 1889 at the Neumarkt works in Nuremberg; he came to England in 1889 and helped to organize the Anglo-German Exhibition held at Earls Court the next year.
His early interest in electrical matters found expression in the importation and sale of such electrical goods as were then available from Continental manufacturers, including some of the early forms of electromedical apparatus. After Rontgen's discovery in 1896, Isenthal became well known as one of the earliest X-ray pioneers in this country. He was a founder member of the Rontgen Society, and was a member of its Council at the first meeting held on the 5th November 1897, under the Presidency of Silvanus Thompson.
As a result of his early work with X-rays and with radium, especially in connection with the wounded from the Boer War, he suffered severely, and his hands became so painful that skin grafting was resorted to in order to give him some relief. In 1954 he was elected an Honorary Member of the British Institute of Radiology—the successor to the Rontgen Society—and was in fact one of the only two non-medical members. He was joint author in 1898 of a textbook entitled 'Practical Radiography'.
His interests, however, were not confined to medical applications, and in 1898 he formed a private company to further many different electrical activities, including the introduction of several items of domestic electrical equipment, such as electric kettles, irons and cookers. Interesting the public in these appliances was, however, an uphill fight in the early years of the century, especially as they were by no means mass-produced articles, and in general the supply companies often had inadequate mains to feed them. Isenthal therefore gradually turned to heavier electrical equipment, while still continuing the manufacture of medical-type switchboards.
He was associated with the Swiss company which developed the Moscicki glass dielectric condensers, and by 1912 was manufacturing them in England. The First World War brought many changes to the Isenthal Co.: suitable glass for condensers could no longer be obtained, and the supply of adjustable resistors and rheostats was inadequate, which led to their extensive manufacture in this country. Subsequently he was associated with the development of the metallized cellulose-film capacitor, especially for use on high-voltage power lines as surge diverters. He also developed and manufactured outdoor 33 kV air-break switchgear required for the post-war expansion of h.v. overhead lines, many of which were also exported.
In collaboration with Dr. E. Pfiffner, he developed the vibratory contact regulator for generator voltage control, about 1923. This type is still in production to-day. At various times, his company manufactured electrostatic voltmeters, and ammeters and wattmeters.
In 1925, the Isenthal Co. was absorbed by the Dubilier Condenser Co., who were able to provide the capital needed for manufacturing developments; and in 1936 Isenthal became chairman of another manufacturing company, Isenthal Automatic Controls (I.A.C. Ltd.), for producing mercury-switch relays and automatic control apparatus. He remained intimately associated with this work until his death.
Isenthal's interests always had a scientific background, and he was a voracious reader of technical literature, for it was his long-established habit to keep an eye open for new discoveries that could be turned to manufacturing profit for the benefit of all.
He became a Fellow of the Royal Photographic Society in 1898, a member of the Royal Institution in 1930, where he used to delight in the opportunity of contact with so many aspects of science, and a Fellow of the Physical Society in 1935. He joined The Institution as an Associate Member in 1910 and was elected a Member in 1912.