Chapter 1: My Early Days in the Bureau (continued)

Jack Hogan (1896–1970) taught me how to operate a theodolite. Tregenza and I did the theodolite observation and slide rule computation of winds together except when one of us was on the bulletin. What at first was considerably difficult with practice became almost automatic. A skilled observer could follow the balloon by theodolite and concurrently compute upper winds by slide rule as a solo effort. John Hogan (1896–1970) was an expert pilot balloon observer because of skill and long experience. He could make theodolite observations of the movement of cirrus cloud between theodolite observations of a pilot balloon. He would make a note of where the pilot balloon was, make observations of movement of cirrus cloud then return to observation of the pilot balloon. He would do all that during the flight of the pilot balloon.

Sometimes it would be possible to observe winds to sixty thousand feet using a pilot balloon as light as 10 grams. With such long flights commencing at 3.30pm it was often 5.30pm by the time the winds were calculated and the message sent to other offices by telegram. An experienced and skilful observer could have the slide rule calculations finished by the time the theodolite observation was finished, thus enabling the message to be sent earlier.

The pilot balloon network in the early 1930s included Melbourne, Sydney and, I think, Adelaide and Brisbane. Later, pilot balloon observations were made at Darwin when Walter Dwyer and Hutchinson were posted to that station with the establishment of the Empire air route between England and Australia. This had been developed after the original plans to develop a dirigible air service between England and Australia had collapsed when the English built airship R101 had crashed in France on its inaugural flight designed to demonstrate the feasibility of operating a regular air passenger service between England and Australia.

Bureau of Meteorology