Obituary
Dr. C. Coleridge Farr, F.R.S. (1866–1943)

New Zealand for the epoch 30th June, 1903. Mr Baird, at present in charge of the Observatory, is carrying out a re-survey of many of the stations established by Dr. Farr and Mr. Skey.

From 1904 until 1910 Dr. Farr acted as lecturer in Physics at Canterbury College, and when a chair in Physics was established in 1910 he was appointed professor. Under his direction the present Physical Laboratory at Canterbury College was built in 1916. After a long apprenticeship in ante-rooms and a tin shed it seemed palatial, but it is proving inadequate for modern requirements.

While at Sydney University Dr. Farr published a paper in the Royal Society Proceedings entitled “Some Expressions for the Radial and Axial Components of Magnetic Force of a Solenoid.” During the time he was at the magnetic observatory he published two papers entitled “Some Observations on the Rate of Dissipation of Electric Charges in Open Air.” and “Interpretation of Milne Seismograms,” the former in the Proc. Roy. Soc. and the latter in the Phil. Mag.

The present observatory in Christchurch was established by Dr. Farr under the New Zealand Government to carry on the work begun in the field. The scope of its operations has been extended from time to time. It constitutes an important link in the chain of world observatories, and through it, Christchurch in particular and New Zealand in general have figured prominently in assisting the scientific staffs of the various famous Antarctic expeditions, setting out from here as their last important place of call. It has also proved a valuable training place for a number of men who later filled important posts in magnetic and meteorological work. Dr. Farr retained a strong interest in magnetic research throughout his life. After his retirement from the Professorship of Physics he undertook further investigations for Sir Douglas Mawson.

While acting as lecturer in Physics Dr. Farr, with the assistance of Professor Florance, measured the radioactive content of typical rocks collected from various parts of New Zealand and from the Sub-antarctic islands. The radioactivity of the local artesian waters was also measured. Papers on this work were published in the Phil. Mag. and the Transactions of the N.Z. Institute. Dr. Farr maintained that there was strong evidence that the trouble experienced in breeding trout fry in the waters, direct from the wells, in Christchurch was due to their radioactivity. As the waters were also deficient in oxygen, it was difficult to come to a definite conclusion. Aerating, which seemed to remove the trouble, at the same time reduced the deficiency of oxygen and caused the waters to lose their radioactivity. The high radioactive content of the local waters was definitely established.

An early association with Professor Threlfald, of Sydney University, interested Dr. Farr in the physical properties of liquid sulphur. Much time and effort was spent with the author of this article in carrying out investigations on this subject. Two papers, “The Viscosity of Liquid Sulphur” and “Some Physical Properties of Gas-freed Sulphur,” were published in the Proc. Roy. Soc.

Meantime, considerable trouble had been experienced with the Lake Coleridge installation, due to the breaking down of insulators. Dr. Farr designed and had constructed a large steel container capable of holding a full-sized insulator and retaining a pressure of 1000 lbs. per sq. inch over a period of a month. Insulators were placed in this pot in coloured water and subjected to this heavy pressure for a long period. Subsequent examination showed that the class of insulator breaking down was porous. Papers entitled “Tests and Investigations on High Tension Insulation” and “Porosity of Porcelain, with Special Reference to High Pressure Insulators for Electric Transmission Lines” were published in the Jour. Amer. Inst. E. E. and in the N.Z. Journ. Science and Technology. This work pointed the way to improved methods of manufacture, and was a guide to the Government in buying insulators from various firms.

With the assistance of Mr N. M. Rogers, Dr. Farr carried through a laborious survey of the helium content of New Zealand's natural gases. Samples were collected in bottles from all over New Zealand and analysed in the laboratory. Dr Farr, travelling on a motor cycle with side-chair, personally collected the samples from many parts of the North Island, and, needless to say, had many adventures in the process. This work and other researches that were being carried out in the laboratory would have been impossible but for a liquid air plant which Dr. Farr installed in the workshop. Incidentally, the liquid air provided the material for many excellent lectures and demonstrations. The results of the helium survey were published in the Journ. of Science of Technology of N.Z. in a paper entitled “Helium in New Zealand.” It is interesting to note that the highest helium content came from Hanmer, but that nowhere was there sufficient to be of commercial interest.

In the latter part of his term as Professor of Physics. Dr. Farr was engaged with Mr C. T. Banwell on an investigation on the possible effect of a transverse magnetic field on the velocity of light. Two papers on this work were published in the Proc. Roy. Soc., one in 1932 and a subsequent one in 1940. Though the results of the experiments seemed to indicate that the field caused a slight increase in the velocity of light, the issue remained uncertain, and any increase was not greater than one part in one hundred million.

Dr. Farr retired from the Chair in Physics in 1936.

As a teacher, Dr. Farr was very popular with his students and his associates. His method of lecturing, often unconventional, and well interspersed with analogies and jokes, was stimulating and effective. His public addresses on the progress of his subject were notable. As a personal friend and keen admirer of Lord Rutherford, Dr. Farr gave Canterbury College students every opportunity to be acquainted with the progress in atomic physics as it unfolded through the years.

Dr. Farr was closely associated with the Canterbury Branch of the Royal Society from the time of his arrival in New Zealand. He was secretary of the local Society in 1903, 1904, 1907, and 1912, and President in 1905 and 1919. He represented the Canterbury Branch on the Council of the Society for a long period of years, and was President of the New Zealand Society in 1929-30. He was Hector Medallist in 1922.